Pixel structure, display device and driving method

Patent metadata

Field	Value
Publication number	US-2018182284-A1
Application number	US-201615501421-A
Country	US
Kind code	A1
Filing date	Apr 26, 2016
Priority date	Feb 4, 2016
Publication date	Jun 28, 2018
Grant date	—

Abstract

A pixel structure is disclosed which includes a first light-emitting device, a second light-emitting device, a common driving unit, a first driving transistor, a second driving transistor, a first switch unit operably coupled between the first driving transistor and the first light-emitting device, and a second switch unit operably coupled between the second driving transistor and the second light-emitting device. The second driving transistor has a channel width-to-length ratio smaller than that of the first driving transistor. The first switch unit and the second switch unit are configured to turn on time-divisionally. Also disclosed are a display device and a method for driving the pixel structure.

First claim

1 . A pixel structure comprising:
a first light-emitting device; a second light-emitting device having a different driving requirement from the first light-emitting device; a common driving unit; a first driving transistor operably coupled to the common driving unit for driving the first light-emitting device; a second driving transistor operably coupled to the common driving unit for driving the second light-emitting device; a first switch unit operably coupled between the first driving transistor and the first light-emitting device; and a second switch unit operably coupled between the second driving transistor and the second light-emitting device, wherein the second driving transistor has a channel width-to-length ratio smaller than that of the first driving transistor, the channel width-to-length ratio of the second driving transistor being adapted to the driving requirement of the second light-emitting device; and wherein the first switch unit and the second switch unit are configured to turn on time-divisionally.

2 . The pixel structure of claim 1 , wherein the first driving transistor and the second driving transistor are independent from each other.

3 . The pixel structure of claim 1 , wherein the first driving transistor has a first channel region, the second driving transistor has a second channel region, and the first channel region is reused as a part of the second channel region.

4 . The pixel structure of claim 3 , wherein the first driving transistor and the second driving transistor have a common gate electrode and a common first electrode, the first driving transistor has a second electrode, the second driving transistor has a second electrode, the first channel region provides an electrical connection between the common first electrode and the second electrode of the first driving transistor when being conductive, and the second channel region provides an electrical connection between the common first electrode and the second electrode of the second driving transistor when being conductive.

5 . The pixel structure of claim 4 , wherein the first driving transistor and the second driving transistor are of a bottom gate type.

6 . The pixel structure of claim 4 , wherein the first driving transistor and the second driving transistor are of a top gate type.

7 . The pixel structure of claim 6 , wherein the common gate electrode comprises a first part and a second part that are spaced from each other in a length direction of the first channel region and the second channel region, wherein the first part defines an effective length of the first channel region, and wherein the first part together with the second part defines an effective length of the second channel region.

8 . The pixel structure of claim 1 , further comprising:
a third light-emitting device having the same driving requirement as the first light-emitting device; and a third switch unit operably coupled between the first driving transistor and the third light-emitting device, wherein the first switch unit, the second switch unit and the third switch unit are configured to turn on time-divisionally.

9 . The pixel structure of claim 8 , wherein the first light-emitting device is a red OLED, the second light-emitting device is a blue OLED, and the third light-emitting device is a green OLED.

10 . A display device comprising the pixel structure as recited in claim 1 .

11 . A method for driving the pixel structure as recited in claim 1 , the method comprising:
controlling the first switch unit and the second switch unit to turn on time-divisionally; driving, by the common driving unit and the first driving transistor, the first light-emitting device to emit light when the first switch unit is turned on; and driving, by the common driving unit and the second driving transistor, the second light-emitting device to emit light when the second switch unit is turned on.

12 . The method of claim 11 , wherein the pixel structure further comprises a third light-emitting device having the same driving requirement as the first light-emitting device and a third switch unit operably coupled between the first driving transistor and the third light-emitting device, the method further comprising:
controlling the first switch unit, the second switch unit and the third switch unit to turn on time-divisionally; and driving, by the common driving unit and the first driving transistor, the third light-emitting device to emit light when the third switch unit is turned on.

13 . A display device comprising the pixel structure as recited in claim 2 .

14 . A display device comprising the pixel structure as recited in claim 3 .

15 . A display device comprising the pixel structure as recited in claim 4 .

16 . A display device comprising the pixel structure as recited in claim 5 .

17 . A display device comprising the pixel structure as recited in claim 6 .

18 . A display device comprising the pixel structure as recited in claim 7 .

19 . A display device comprising the pixel structure as recited in claim 8 .

20 . A display device comprising the pixel structure as recited in claim 9 .

Assignees

• Boe Technology Group Co Ltd

Inventors

• Chung Chiehhsing

Classifications

• G09G2300/0852

  being a dynamic memory with more than one capacitor · CPC title

• G09G2300/0847

  being a dynamic memory without any storage capacitor, i.e. with use of parasitic capacitances as storage elements · CPC title

• G09G2310/0235

  Field-sequential colour display · CPC title

• G09G3/3233 Primary

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