Pixel circuit, organic electroluminescent display panel and display apparatus

• US 9,741,288 B2
• Filed: 11/28/2014
• Issued: 08/22/2017
• Est. Priority Date: 08/15/2014
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd., Hefei Xinsheng Optoelectric Technology Co. Ltd. (BOE Technology Group Co., Ltd.)
• Original Assignee: BOE Technology Group Co., Ltd., Hefei Xinsheng Optoelectric Technology Co. Ltd. (BOE Technology Group Co., Ltd.)
• Inventors: Zhang, Yuting
• Primary Examiner(s): Haley, Joseph
• Application Number:
  US14/773,491
• Publication Number:
  US 20160203761A1
• Time in Patent Office: 998 Days
• Field of Search: None
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0852 being a dynamic memory with more than one capacitor
• CPC Class Codes: G09G 2300/0861 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 Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/0262 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 Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0295 by monitoring each display pixel
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

A pixel circuit, an organic electroluminescent display panel and a display apparatus are provided. The pixel circuit comprises: a light-emitting device (D1), a drive control module (1), a reset control module (2), a charge control module (3) and a light-emitting control module (4). The reset control module (2) is used for resetting the light-emitting device (D1) in an internal compensation mode, and exporting a current signal of the drive control module (1) for driving the light-emitting device (D1) and comparing the same with a preset standard current value to determine a compensation factor in an external compensation mode. The charge control module (3) is used for charging and writing a data signal (Data) into the drive control module (1) in the internal compensation mode and writing the data signal (Data) into the drive control module (1) in the external compensation mode. The light-emitting control module (4) is used for charging the drive control module (1) and controlling the drive control module (1) to drive the light-emitting device (D1) to emit light in the internal compensation mode, and controlling the drive control module (1) to drive the light-emitting device (D1) to emit light in the external compensation mode. Therefore, a same pixel circuit can be shared for both internal compensation and external compensation.

Claims

1. A pixel circuit, comprising:

a light-emitting device, a drive control module, a reset control module, a charge control module and a light-emitting control module, wherein,

the reset control module has a control terminal connected with a reset signal terminal, an input terminal connected with a first level signal terminal, and an output terminal connected with an output terminal of the drive control module and an input terminal of the light-emitting device respectively;

the reset control module is used for resetting the light-emitting device in an internal compensation mode, and exporting a current signal of the drive control module for driving the light-emitting device and comparing the same with a preset standard current value to determine a compensation factor in an external compensation mode;

the charge control module has a control terminal connected with a scan signal terminal, an input terminal connected with a data signal terminal, and an output terminal connected with a first input terminal of the drive control module;

the charge control module is used for charging the drive control module and writing a data signal into the drive control module in the internal compensation mode, and writing the data signal into the drive control module in the external compensation mode;

the light-emitting control module has a control terminal connected with a light-emitting signal terminal, an input terminal connected with a second level signal terminal, and an output terminal connected with a second input terminal of the drive control module;

the light-emitting control module is used for charging the drive control module and controlling the drive control module to drive the light-emitting device to emit light in the internal compensation mode, and controlling the drive control module to drive the light-emitting device to emit light in the external compensation mode;

an output terminal of the light-emitting device is grounded, wherein, in the Internal compensation mode, at a reset stage, the reset control module is in an ON state under control of the reset signal terminal, the first level signal terminal is connected with the light-emitting device, the first level signal terminal resets the light-emitting device;

at a charging stage, the charge control module is in an ON state under control of the scan signal terminal, the data signal terminal is connected with the drive control module, the light-emitting control module is in an ON state under control of the light-emitting signal terminal, the second level signal terminal is connected with the drive control module, the data signal terminal and the second level signal terminal charge the drive control module;

at a compensation stage, the data signal terminal writes a data signal into the drive control module under control of the scan signal terminal;

at a light-emitting stage, under control of the light-emitting signal terminal, the second level signal terminal controls the drive control module to drive the light-emitting device to emit light.

2. The pixel circuit according to claim 1, wherein, in the external compensation mode, under control of the scan signal terminal, the data signal terminal writes a data signal into the drive control module;

under control of the light-emitting signal terminal, the second level signal terminal controls the drive control module to drive the light-emitting device to emit light;

under control of the reset signal terminal, the first level signal terminal exports a current signal of the drive control module for driving the light-emitting device, and the exported current signal is compared with a preset standard current value to determine a compensation factor of the data signal.

3. The pixel circuit according to claim 1, wherein, in the external compensation mode, under control of the scan signal terminal, the data signal terminal writes a data signal into the drive control module;

under control of the light-emitting signal terminal, the second level signal terminal controls the drive control module to drive the light-emitting device to emit light;

under control of the reset signal terminal, the first level signal terminal exports a current signal of the drive control module for driving the light-emitting device, and the exported current signal is compared with a preset standard current value to determine a compensation factor of the data signal.

4. The pixel circuit according to claim 1, wherein, the drive control module includes a driving transistor and a capacitor, wherein,

a gate of the driving transistor is connected with the charge control module, a source of the driving transistor is connected with the light-emitting control module, and a drain of the driving transistor is connected with the light-emitting device and the reset control module, respectively;

the capacitor is connected between the gate and the drain of the driving transistor.

5. The pixel circuit according to claim 1, wherein, the drive control module includes a driving transistor and a capacitor, wherein,

a gate of the driving transistor is connected with the charge control module, a source of the driving transistor is connected with the light-emitting control module, and a drain of the driving transistor is connected with the light-emitting device and the reset control module, respectively;

the capacitor is connected between the gate and the drain of the driving transistor.

6. The pixel circuit according to claim 2, wherein, the drive control module includes a driving transistor and a capacitor, wherein,

a gate of the driving transistor is connected with the charge control module, a source of the driving transistor is connected with the light-emitting control module, and a drain of the driving transistor is connected with the light-emitting device and the reset control module, respectively;

the capacitor is connected between the gate and the drain of the driving transistor.

7. The pixel circuit according to claim 3, wherein, the drive control module includes a driving transistor and a capacitor, wherein,

a gate of the driving transistor is connected with the charge control module, a source of the driving transistor is connected with the light-emitting control module, and a drain of the driving transistor is connected with the light-emitting device and the reset control module, respectively;

the capacitor is connected between the gate and the drain of the driving transistor.

8. The pixel circuit according to claim 4, wherein, the reset control module includes a first switching transistor, wherein

a gate of the first switching transistor is connected with the reset signal terminal, a source of the first switching transistor is connected with the first level signal terminal, and a drain of the first switching transistor is connected with the drain of the driving transistor and the light-emitting device.

9. The pixel circuit according to claim 5, wherein, the reset control module includes a first switching transistor, wherein

a gate of the first switching transistor is connected with the reset signal terminal, a source of the first switching transistor is connected with the first level signal terminal, and a drain of the first switching transistor is connected with the drain of the driving transistor and the light-emitting device.

10. The pixel circuit according to claim 4, wherein, the charge control module includes a second switching transistor, wherein,

a gate of the second switching transistor is connected with the scan signal terminal, a source of the second switching transistor is connected with the data signal terminal, and a drain of the second switching transistor is connected with the gate of the driving transistor.

11. The pixel circuit according to claim 5, wherein, the charge control module includes a second switching transistor, wherein,

a gate of the second switching transistor is connected with the scan signal terminal, a source of the second switching transistor is connected with the data signal terminal, and a drain of the second switching transistor is connected with the gate of the driving transistor.

12. The pixel circuit according to claim 4, wherein, the light-emitting control module includes a third switching transistor;

wherein

a gate of the third switching transistor is connected with the light-emitting signal terminal, a source of the third switching transistor is connected with the second level signal terminal, and a drain of the third switching transistor is connected with the source of the driving transistor.

13. The pixel circuit according to claim 5, wherein, the light-emitting control module includes a third switching transistor;

wherein

a gate of the third switching transistor is connected with the light-emitting signal terminal, a source of the third switching transistor is connected with the second level signal terminal, and a drain of the third switching transistor is connected with the source of the driving transistor.

14. An organic electroluminescent display panel, comprising a plurality of pixel circuits arranged in array, the pixel circuits being the pixel circuit according to claim 1.

15. The organic electroluminescent display panel according to claim 14, further comprising:

reset signal lines and light-emitting signal lines positioned in gaps among respective rows of the pixel circuits at intervals, scan signal lines positioned in gaps among respective rows of pixel circuits having the light-emitting signal lines, and data signal lines positioned in gaps among respective columns of pixel circuits;

wherein,

respective reset signal lines are connected with reset signal terminals in adjacent rows of respective pixel circuits;

respective light-emitting signal lines are connected with light-emitting signal terminals in adjacent rows of respective pixel circuits;

two scan signal lines are arranged in the gaps where the respective light-emitting signal lines are positioned respectively;

the two scan signal lines are connected with the scan signal terminals in adjacent rows of respective pixel circuits respectively; and

two adjacent scan signal lines positioned in different gaps respectively are electrically connected;

two data signal lines are arranged in gaps among respective columns of pixel circuits respectively;

the two data signal lines are connected with the data signal terminals of odd-numbered or even-numbered rows of pixel circuits in adjacent columns of respective pixel circuits;

in the external compensation mode, a data signal is alternatively input to odd-numbered columns and even-numbered columns of data signal lines.

16. The organic electroluminescent display panel according to claim 15, further comprising:

first level signal lines and second level signal lines positioned in gaps among respective columns of pixel circuits at intervals;

wherein,

the respective first level signal lines are connected with the first level signal terminals in adjacent columns of respective pixel circuits;

the respective second level signal lines are connected with the second level signal terminals in adjacent columns of respective pixel circuits.

17. The organic electroluminescent display panel according to claim 16, wherein, the first level signal lines and the second level signal lines are arranged on a same layer, and are all arranged on a layer different from that of the data signal lines.

18. The organic electroluminescent display panel according to claim 17, wherein, a film layer where the first level signal lines and the second level signal lines are positioned is above a film layer where anodes of the light-emitting devices in the pixel circuits are positioned.

19. A display apparatus comprising the organic electroluminescent display panel according to claim 7.