Driving method of pixel circuit and driving device thereof

• US 9,881,554 B2
• Filed: 09/16/2015
• Issued: 01/30/2018
• Est. Priority Date: 02/11/2015
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: BOE Technology Group Co., Ltd.
• Inventors: Meng, Song, Song, Danna
• Primary Examiner(s): Chow, Van
• Application Number:
  US14/907,448
• Publication Number:
  US 20160232848A1
• Time in Patent Office: 867 Days
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element

Abstract

Embodiments of the present disclosure relate to a technical field of display technology, and provide a driving method for a pixel circuit and a driving device thereof. A problem of cost increase can be solved which is caused by an increase in a number of storages when adjustment is made by way of Gamma curve and table lookup, by means of the technical solutions according to embodiments of the present disclosure. The driving method of the pixel circuit includes acquiring brightness information of a display screen in a light-emitting phase (S101); determining a duty cycle of a pulse signal according to the brightness information (S102); inputting a high level to the first voltage terminal, and inputting the pulse signal with the duty cycle to a gate of the first switching transistor by the first gate line (S103).

Claims

1. A driving method for a pixel circuit, the pixel circuit including a driving transistor, a light-emitting device having an anode connected with a second electrode of the driving transistor, and a first switching transistor, the first switching transistor having a first electrode connected with a first voltage terminal, a second electrode connected with a first electrode of the driving transistor, and a gate connected with a first gate line, wherein, the driving method comprises:

in a light-emitting phase, acquiring a brightness information of a display image;

determining a duty cycle of a pulse signal corresponding to the brightness information from a table storing a correspondence between the brightness information of the display image and the duty cycle of the pulse signal;

inputting a high level to the first voltage terminal, and inputting a pulse signal with the duty cycle to the gate of the first switching transistor by the first gate line, to control luminescence time of the light-emitting device.

2. The driving method for the pixel circuit of claim 1, wherein the brightness information includes a brightness value of the display image.

3. The driving method for the pixel circuit of claim 1, wherein the brightness information includes a display mode corresponding to a brightness value of the display screen.

4. The driving method for the pixel circuit of claim 2, wherein in a case that the brightness value is a percentage value, the determining a duty cycle of a pulse signal according to the brightness value includes:

a percentage value of the brightness value being equal to that of the duty cycle.

5. The driving method for the pixel circuit of claim 4, wherein the pixel circuit further includes a second switching transistor, a first capacitor and a second capacitor,

the second switching transistor has a first electrode connected with a data line, a second electrode connected with a gate of the driving transistor, and a gate connected with a second gate line;

the first capacitor has one terminal connected with the gate of the driving transistor, and another terminal connected with the anode of the light-emitting device;

the second capacitor has one terminal connected with the anode of the light-emitting device, and another terminal connected with the second voltage terminal.

6. The driving method for the pixel circuit of claim 5, wherein

the driving transistor, the first switching transistor and the second switching transistor are all N type transistors;

or,

the driving transistor, the first switching transistor and the second switching transistor are all P type transistors.

7. The driving method for the pixel circuit of claim 6, wherein

the driving transistor, the first switching transistor and the second switching transistor are all enhancement mode transistors or depletion mode transistors.

8. The driving method for the pixel circuit of claim 7, wherein, in a case that both the first switching transistor and the second switching transistor are N type enhancement mode transistors,

the first electrode of the driving transistor, the first electrode of the first switching transistor and the first electrode of the second switching transistor are drains, and their second electrodes are sources.

9. The driving method for the pixel circuit of claim 8, wherein the driving method includes:

in a reset phase, inputting a low level to the first voltage terminal, inputting a high level to the first gate line, the first switching transistor being turned on, inputting a high level to the second gate line, the second switching transistor being turned on, and inputting a reference voltage to the data line;

in a compensation phase, inputting a high level to the first gate line, the first switching transistor being turned on, inputting a high level to the second gate line, the second switching transistor being turned on, inputting a reference voltage to the data line, inputting a high level to the first voltage terminal, storing a threshold voltage of the driving transistor in the first capacitor;

in a writing phase, inputting a high level to the second gate line, the second switching transistor being turned on, a low level being input to the first gate line, the second switching transistor being in OFF state, writing the data voltage input to the data line into the gate of the driving transistor;

in a light-emitting phase, inputting a high level to the first voltage terminal, inputting a low level to the second gate line, the second switching transistor being turned off, and inputting a pulse signal with the duty cycle to the first gate line.

10. The driving method for the pixel circuit of claim 3, wherein in a case that the brightness value is a percentage value, the determining a duty cycle of a pulse signal according to the brightness value includes:

a percentage value of the brightness value being equal to that of the duty cycle.

11. The driving method for the pixel circuit of claim 10, wherein the pixel circuit further includes a second switching transistor, a first capacitor and a second capacitor,

the second switching transistor has a first electrode connected with a data line, a second electrode connected with a gate of the driving transistor, and a gate connected with a second gate line;

the first capacitor has one terminal connected with the gate of the driving transistor, and another terminal connected with the anode of the light-emitting device;

the second capacitor has one terminal connected with the anode of the light-emitting device, and another terminal connected with the second voltage terminal.

12. The driving method for the pixel circuit of claim 11, wherein

the driving transistor, the first switching transistor and the second switching transistor are all N type transistors;

or,

the driving transistor, the first switching transistor and the second switching transistor are all P type transistors.

13. The driving method for the pixel circuit of claim 12, wherein

the driving transistor, the first switching transistor and the second switching transistor are all enhancement mode transistors or depletion mode transistors.

14. The driving method for the pixel circuit of claim 13, wherein, in a case that both the first switching transistor and the second switching transistor are N type enhancement mode transistors,

the first electrode of the driving transistor, the first electrode of the first switching transistor and the first electrode of the second switching transistor are drains, and their second electrodes are sources.

15. The driving method for the pixel circuit of claim 14, wherein the driving method includes:

in a reset phase, inputting a low level to the first voltage terminal, inputting a high level to the first gate line, the first switching transistor being turned on, inputting a high level to the second gate line, the second switching transistor being turned on, and inputting a reference voltage to the data line;

in a compensation phase, inputting a high level to the first gate line, the first switching transistor being turned on, inputting a high level to the second gate line, the second switching transistor being turned on, inputting a reference voltage to the data line, inputting a high level to the first voltage terminal, storing a threshold voltage of the driving transistor in the first capacitor;

in a writing phase, inputting a high level to the second gate line, the second switching transistor being turned on, a low level being input to the first gate line, the second switching transistor being in OFF state, writing the data voltage input to the data line into the gate of the driving transistor;

in a light-emitting phase, inputting a high level to the first voltage terminal, inputting a low level to the second gate line, the second switching transistor being turned off, and inputting a pulse signal with the duty cycle to the first gate line.

16. A driving device for a pixel circuit, the pixel circuit comprising a driving transistor, a light-emitting device having an anode connected with a second electrode of the driving transistor, and a first switching transistor, the first switching transistor having a first electrode connected with a first voltage terminal, a second electrode connected with a first electrode of the driving transistor, and a gate connected with a first gate line, wherein, the driving device comprises an acquiring unit, a duty cycle determining unit and a pulse signal triggering unit,

the acquiring unit is used for acquiring brightness information of a display screen in a light-emitting phase of the pixel circuit;

the duty cycle determining unit is used for determining a duty cycle of a pulse signal according to the brightness information;

the pulse signal triggering unit is used for inputting the pulse signal with the duty cycle to the gate of the first switching transistor through the first gate line when a high level is input to the first voltage terminal, to control luminescence time of the light-emitting device.