Display substrate, display equipment and regional compensation method

• US 10,163,393 B2
• Filed: 03/29/2017
• Issued: 12/25/2018
• Est. Priority Date: 08/19/2016
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: BOE Technology Group Co., Ltd.
• Inventors: Yang, Shengji, Dong, Xue, Lv, Jing, Chen, Xiaochuan, Liu, Dongni, Wang, Lei, Xiao, Li, Fu, Jie, Lu, Pengcheng, Yue, Han
• Primary Examiner(s): Giesy, Adam R
• Application Number:
  US15/562,828
• Publication Number:
  US 20180286310A1
• Time in Patent Office: 636 Days
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/029 by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
• 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 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3241 the current through the light-emitting element being set using a data current provided by the data driver, e.g. by using a two-transistor current mirror
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes
• CPC Class Codes: G09G 3/3283 in which the data driver supplies a variable data current for setting the current through, or the voltage across, the light-emitting elements

Abstract

A display substrate, a display equipment and a regional compensation method. The display substrate includes a pixel array, a common cathode current detection circuit, and a data signal compensation circuit. The common cathode current detection circuit is configured to detect a total current flowing through each common cathode; the data signal compensation circuit is configured to receive the pixel light emitting current of the first sub-pixel, receive the total current of the common cathode, and calculate compensation data for each of the sub-pixels according to the pixel light emitting current and the total current of the common cathode.

Claims

1. A display substrate comprising a pixel array, a common cathode current detection circuit, and a data signal compensation circuit, wherein

the pixel array comprises a plurality of sub-pixels arranged in a matrix, each of the sub-pixels comprises an organic light emitting diode, which comprises an anode, an organic luminescent layer, and a cathode,

the plurality of sub-pixels comprise first sub-pixels and second sub-pixels, each first sub-pixel further comprises a pixel current acquisition circuit configured to acquire a pixel light emitting current of the organic light emitting diode in the first sub-pixel;

the pixel array is divide into a plurality of cathode common areas each comprising M compensation areas each comprising N sub-pixels, the N sub-pixels comprising one first sub-pixel, organic light emitting diodes of M×

N sub-pixels in a same cathode common area share one common cathode, and M and N both being natural numbers greater than 1;

the common cathode current detection circuit is configured to detect a total current flowing through each common cathode;

the data signal compensation circuit is configured to receive the pixel light emitting current of the first sub-pixel in each of the M compensation areas, receive the total current of the common cathode, and calculate compensation data for each of the sub-pixels according to the pixel light emitting current of the first sub-pixel in each of the M compensation areas and the total current of the common cathode.

2. The display substrate of claim 1, wherein the data signal compensation circuit is further configured to superimpose the compensation data to the display data of the sub-pixels while the display substrate is normally operating for display to obtain updated display data and transmit the updated display data to the sub-pixels.

3. The display substrate of claim 2, wherein the plurality of the cathode common areas are of rectangle and arranged in a matrix.

4. The display substrate of claim 2, wherein M=4 and N=9.

5. The display substrate of claim 2, wherein the first sub-pixel further comprises a driving transistor, a light emission control transistor, a data writing transistor, an acquisition control transistor, and a storage capacitor.

6. The display substrate of claim 5, wherein a first electrode of the driving transistor is electrically connected with a first node, a gate electrode of the driving transistor is electrically connected with a second node, and a second electrode of the driving transistor is electrically connected with a third node;

the first node is electrically connected with a power supply line to receive a power supply voltage;

a first electrode of the light emission control transistor is electrically connected with the third node, a gate electrode of the light emission control transistor is electrically connected with a light emission control signal line to receive a light emission control signal, a second electrode of the light emission control transistor is electrically connected with the anode of the organic light emitting diode;

a first electrode of the data writing transistor is electrically connected with a data signal line to acquire a data signal, a gate electrode of the data writing transistor is electrically connected with a scanning signal line to receive a scanning signal, and a second electrode of the data writing transistor is electrically connected with the second node;

a first electrode of the acquisition control transistor is electrically connected with the third node, a gate electrode of the acquisition control transistor is electrically connected with an acquisition control signal line to receive an acquisition control signal, and a second electrode of the acquisition control transistor is electrically connected with the pixel current acquisition circuit;

a first end of the storage capacitor is electrically connected with the first node, and a second end of the storage capacitor is electrically connected with the second node;

the cathode of the organic light emitting diode is part of the common cathode, and the common cathode is electrically connected with the common cathode current detection circuit.

7. The display substrate of claim 2, further comprising:

a scan driver, a data driver, a power supply, a controller, power supply lines, light emission control signal lines, data signal lines, scanning signal lines and acquisition control signal lines, wherein,

the scan driver is configured to provide light emission control signals, scanning signals and acquisition control signals to the sub-pixels via the light emission control signal lines, the scanning signal lines and the acquisition control signal lines respectively;

the data driver is configured to provide data signals to the sub-pixels via the data signal lines;

the power supply is configured to provide a power supply voltage to the sub-pixels via the power supply lines;

the controller is configured to control the common cathode current detection circuit, the data signal compensation circuit, the pixel current acquisition circuit, the scan driver, the data driver and the power supply to allow the display substrate to work normally.

8. The display substrate of claim 1, wherein calculating of the compensation data for each of the sub-pixels according to the pixel light emitting current of each first sub-pixel in the M compensation areas and the total current of the common cathode comprises:

calculating an average light emitting current of the cathode common areas according to the total current of the common cathode of the cathode common area; and

superimposing the compensation data onto raw data applied to the first sub-pixels such that the pixel light emitting currents equal the average current.

9. The display substrate of claim 1, further comprising a memory, wherein the memory is configured to store the compensation data for each of the sub-pixels.

10. The display substrate of claim 1, wherein the plurality of the cathode common areas are of rectangle and arranged in a matrix.

11. The display substrate of claim 1, wherein M=4 and N=9.

12. The display substrate of claim 1, wherein the first sub-pixel further comprises a driving transistor, a light emission control transistor, a data writing transistor, an acquisition control transistor, and a storage capacitor.

13. The display substrate of claim 12, wherein a first electrode of the driving transistor is electrically connected with a first node, a gate electrode of the driving transistor is electrically connected with a second node, and a second electrode of the driving transistor is electrically connected with a third node;

the first node is electrically connected with a power supply line to receive a power supply voltage;

a first electrode of the light emission control transistor is electrically connected with the third node, a gate electrode of the light emission control transistor is electrically connected with a light emission control signal line to receive a light emission control signal, a second electrode of the light emission control transistor is electrically connected with the anode of the organic light emitting diode;

a first electrode of the data writing transistor is electrically connected with a data signal line to acquire a data signal, a gate electrode of the data writing transistor is electrically connected with a scanning signal line to receive a scanning signal, and a second electrode of the data writing transistor is electrically connected with the second node;

a first electrode of the acquisition control transistor is electrically connected with the third node, a gate electrode of the acquisition control transistor is electrically connected with an acquisition control signal line to receive an acquisition control signal, and a second electrode of the acquisition control transistor is electrically connected with the pixel current acquisition circuit;

a first end of the storage capacitor is electrically connected with the first node, and a second end of the storage capacitor is electrically connected with the second node;

the cathode of the organic light emitting diode is part of the common cathode, and the common cathode is electrically connected with the common cathode current detection circuit.

14. The display substrate of claim 1, further comprising:

a scan driver, a data driver, a power supply, a controller, power supply lines, light emission control signal lines, data signal lines, scanning signal lines and acquisition control signal lines, wherein,

the scan driver is configured to provide light emission control signals, scanning signals and acquisition control signals to the sub-pixels via the light emission control signal lines, the scanning signal lines and the acquisition control signal lines respectively;

the data driver is configured to provide data signals to the sub-pixels via the data signal lines;

the power supply is configured to provide a power supply voltage to the sub-pixels via the power supply lines;

the controller is configured to control the common cathode current detection circuit, the data signal compensation circuit, the pixel current acquisition circuit, the scan driver, the data driver and the power supply to allow the display substrate to work normally.

15. A display equipment comprising the display substrate of claim 1.

16. A regional compensation method for the display substrate of claim 1, comprising:

applying a same raw data signal to the M×

N sub-pixels in the cathode common area and driving the M×

N sub-pixels to emit light;

acquiring the pixel light emitting current of the organic light emitting diode OLED in each first sub-pixel in the M compensation areas in the cathode common area;

acquiring a total current flowing through the common cathode in the cathode common area; and

calculating compensation data for each of the sub-pixels according to the pixel light emitting current of the organic light emitting diode in each first sub-pixel in the M compensation areas and the total current of the common cathode.

17. The regional compensation method of claim 16, wherein,

in a course of displaying normally, superimposing the compensation data for each sub-pixel to display data for the sub-pixel to obtain updated display data;

and

transmitting the updated display data to the sub-pixel to allow the organic light emitting diode in the sub-pixel to emit light.

18. The regional compensation method of claim 16, wherein, calculating of the compensation data for each of the sub-pixels according to the pixel light emitting current and the total current of the common cathode comprises:

dividing the total current of the common cathode by a number M×

N of the sub-pixels in the cathode common areas to obtain an average light emitting current;

superimposing the compensation data onto raw data applied to the first sub-pixels in the cathode common areas such that the pixel light emitting currents equal the average current.

19. The regional compensation method of claim 16, further comprising storing the compensation data for each of the sub-pixels,

wherein compensation data for N sub-pixels in each of the compensation areas of the cathode common area are same.

20. The regional compensation method of claim 16, wherein, the display substrate executes the regional compensation method each time when it is powered on, or

the display substrate executes the regional compensation method periodically in terms of a preset interval in operation.