Pixel circuit and organic light emitting display

Patent metadata

Field	Value
Publication number	US-2021390905-A1
Application number	US-202017129689-A
Country	US
Kind code	A1
Filing date	Dec 21, 2020
Priority date	Jun 12, 2020
Publication date	Dec 16, 2021
Grant date	—

Abstract

A pixel circuit includes a first scan thin-film transistor (TFT) receiving a first data voltage, a first storage capacitor maintaining a first gate voltage corresponding to the first data voltage, a first driving TFT having a gate connected to the first storage capacitor and controlling the amount of a first driving current based on the first gate voltage, a first light-emitting device emitting light according to the first driving current, a second scan TFT receiving a second data voltage in response to an emission control signal, a second driving TFT having a gate connected to the gate of the first driving TFT and a source receiving the second data voltage and controlling the amount of a second driving current based on a difference between the first gate voltage and the second data voltage, and a second light-emitting device emitting light according to the second driving current.

First claim

What is claimed is:

1 . A pixel circuit including a first pixel circuit and a second pixel circuit, wherein the first pixel circuit comprises:
a first scan thin-film transistor (TFT) receiving a first data voltage in response to a first scan signal; a first storage capacitor maintaining a first gate voltage corresponding to the first data voltage; a first driving TFT having a gate connected to the first storage capacitor and controlling the amount of a first driving current based on the first gate voltage; and a first light-emitting device emitting light according to the first driving current, and the second pixel circuit comprises:
a second scan TFT receiving a second data voltage in response to an emission control signal;
a second driving TFT having a gate connected to the gate of the first driving TFT and a source receiving the second data voltage through the second scan TFT and is controlling the amount of a second driving current based on a difference between the first gate voltage and the second data voltage; and
a second light-emitting device emitting light according to the second driving current.

2 . The pixel circuit of claim 1 , wherein the first pixel circuit comprises:
a first compensation TFT connecting a drain and the gate of the first driving TFT to each other in response to the first scan signal; a first gate initialization TFT applying an initialization voltage to the gate of the first driving TFT in response to a second scan signal; and a first anode initialization TFT applying the initialization voltage to an anode of the first light-emitting device in response to a third scan signal.

3 . The pixel circuit of claim 2 , wherein the second pixel circuit further comprises:
a second anode initialization TFT applying the initialization voltage to an anode of the second light-emitting device in response to the third scan signal.

4 . The pixel circuit of claim 2 , wherein the second pixel circuit further comprises:
a second anode initialization TFT connecting an anode of the second light-emitting device to the anode of the first light-emitting device in response to the third scan signal.

5 . The pixel circuit of claim 1 , wherein the first pixel circuit comprises:
a first emission control TFT applying a first driving voltage to a source of the first driving TFT in response to the emission control signal; and a second emission control TFT transmitting the first driving current from the first driving TFT to the first light-emitting device in response to the emission control signal.

6 . The pixel circuit of claim 1 , wherein the second pixel circuit further comprises:
a first current transmission TFT transmitting the second driving current from the second driving TFT to the second light-emitting device in response to the emission control signal.

7 . The pixel circuit of claim 1 , further comprising a third pixel circuit,
wherein the third pixel circuit comprises: a third scan TFT receiving a third data voltage in response to the emission control signal; a third driving TFT having a gate connected to the gate of the first driving TFT and a source receiving the third data voltage through the third scan TFT and controlling the amount of a third driving current based on a difference between the first gate voltage and the third data voltage; and a third light-emitting device emitting light according to the third driving current.

8 . The pixel circuit of claim 7 , wherein the third pixel circuit further comprises:
a third anode initialization TFT connecting an anode of the third light-emitting device to an anode of the first light-emitting device in response to a third scan signal.

9 . The pixel circuit of claim 7 , wherein the third pixel circuit further comprises:
a second current transmission TFT transmitting the third driving current from the third driving TFT to the third light-emitting device in response to the emission control signal.

10 . The pixel circuit of claim 1 , wherein the second pixel circuit comprises:
a second compensation TFT connecting a gate of the second driving TFT to the gate of the first driving TFT in response to the first scan signal; and a second storage capacitor connected to the gate of the second driving TFT and maintaining the first gate voltage.

11 . The pixel circuit of claim 10 , further comprising a third pixel circuit, wherein the third pixel circuit comprises:
a third scan TFT receiving a third data voltage in response to the emission control signal; a third compensation TFT receiving the first gate voltage in response to the first scan signal; and a third driving TFT having a gate receiving the first gate voltage through the third compensation TFT and a source receiving the third data voltage through the third scan TFT and controlling the amount of a third driving current based on a difference between the first gate voltage and the third data voltage; a third storage capacitor connected to the gate of the third driving TFT and maintaining the first gate voltage; and a third light-emitting device emitting light according to the third driving current.

12 . An organic light-emitting display comprising:
a substrate on which a first display area and a second display area are defined; first pixels arranged in the first display area and each implemented as a first pixel circuit; and second pixels arranged in the second display area and including two pixels each implemented as the first pixel circuit and a second pixel circuit, wherein the first pixel circuit comprises: a first scan thin film transistor (TFT) receiving a first data voltage in response to a first scan signal; a first storage capacitor maintaining a first gate voltage corresponding to the first data voltage; a first driving TFT having a gate connected to the first storage capacitor and controlling the amount of a first driving current based on the first gate voltage; and a first light-emitting device emitting light according to the first driving current, and wherein the second pixel circuit comprises: a second scan TFT receiving a second data voltage in response to an emission control signal; a second driving TFT having a gate connected to the gate of the first driving TFT and a source receiving the second data voltage through the second scan TFT and controlling the amount of a second driving current based on a difference between the first gate voltage and the second data voltage; and a second light-emitting device emitting light according to the second driving current.

13 . An organic light-emitting display of claim 12 , wherein the second display area includes a transmission area between the second pixels.

Assignees

• Samsung Display Co Ltd

Inventors

• Kim Keunwoo

Classifications

• G09G3/3233 Primary

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

• G09G2320/0233

  Improving the luminance or brightness uniformity across the screen · CPC title

• G09G3/3258 Primary

  with pixel circuitry controlling the voltage across the light-emitting element · CPC title

• G09G3/3266

  Details of drivers for scan 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