Pixel driving circuit and driving method thereof, array substrate and display apparatus

• US 9,760,199 B2
• Filed: 09/02/2014
• Issued: 09/12/2017
• Est. Priority Date: 05/14/2014
• Status: Active Grant

• Current Assignee: Beijing BOE Optoelectronics Technology Co Ltd. (BOE Technology Group Co., Ltd.), BOE Technology Group Co., Ltd.
• Original Assignee: Beijing BOE Optoelectronics Technology Co Ltd. (BOE Technology Group Co., Ltd.), BOE Technology Group Co., Ltd.
• Inventors: Yang, Shengji
• Primary Examiner(s): Jansen, II, Michael J
• Application Number:
  US14/443,445
• Publication Number:
  US 20160062522A1
• Time in Patent Office: 1,106 Days
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: G09G 2300/043 Compensation electrodes or other additional electrodes in matrix displays related to distortions or compensation signals, e.g. for modifying TFT threshold voltage in column driver
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0248 Precharge or discharge of column electrodes before or after applying exact column voltages
• CPC Class Codes: G09G 2310/0278 Details of driving circuits arranged to drive both scan and data electrodes
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2354/00 Aspects of interface with display user
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes
• CPC Class Codes: G09G 3/3291 in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements

Abstract

A pixel driving circuit and method, an array substrate and a display apparatus are provided. The driving circuit includes: a data line, a first scan line, a second scan line, a power supply line, a light emitting device, a display sub-circuit and a photosensitive sub-circuit; the display sub-circuit is connected to the data line, the first scan line, the second scan line, the power supply line and the light emitting device, and is configured to drive the light emitting device to emit light for display under the control of the first scan line, the second scan line, the data line and the power supply line; and the photosensitive sub-circuit is connected to the second scan line, and is configured to sense a touch action under the control of the second scan line.

Claims

1. A pixel driving circuit comprising:

a data line, a first scan line, a second scan line, a power supply line, a light emitting device, a display sub-circuit and a photosensitive sub-circuit;

wherein

the display sub-circuit is directly connected to the data line, the first scan line, the second scan line, the power supply line and the light emitting device, and is configured to drive the light emitting device to emit light for display under control of the first scan line, the second scan line, the data line and the power supply line; and

the photosensitive sub-circuit is directly connected to the second scan line, and is configured to sense a touch action under control of the second scan line;

wherein the photosensitive sub-circuit comprises;

a reference signal line, a signal detecting line, a first storage capacitor, a signal sensing unit and a signal reading-writing unit;

wherein

the signal reading-writing unit is directly connected to a first terminal of the first storage capacitor, the second scan line and the signal detecting line, and is configured to write a signal on the signal detecting line into the first terminal of the first storage capacitor, or to read out a signal stored in the first storage capacitor and transmit the same to the signal detecting line under the control of the second scan line; and

the signal sensing unit is directly connected to the second scan line, the reference signal line and the first storage capacitor, and is configured to write a signal on the reference signal line and a sensed photosensitive signal into the first storage capacitor under the control of the second scan line;

the signal reading-writing unit comprises a sixth transistor having a gate connected to the second scan line, a source connected to the first terminal of the first storage capacitor, and a drain connected to the signal detecting line, and being configured to write the signal on the signal detecting line into the first terminal of the first storage capacitor, or to read out the signal stored in the first storage capacitor and transmit the same to the signal detecting line under the control of the second scan line; and

the signal sensing unit comprises a seventh transistor and a photosensitive transistor, wherein the seventh transistor has a gate directly connected to the second scan line, a source directly connected to the reference signal line and a drain directly connected to a gate of the photosensitive transistor and a second terminal of the first storage capacitor, and is configured to write the signal on the reference signal line into the second terminal of the first storage capacitor under the control of the second scan line; and

the photosensitive transistor has a gate connected to a source thereof and a drain connected to the first terminal of the first storage capacitor, and is configured to sense the photosensitive signal and write the same into the first terminal of the first storage capacitor.

2. The pixel driving circuit of claim 1, wherein the display sub-circuit comprises a second storage capacitor, a driving transistor, a charging and discharging unit, and a light emitting control unit;

wherein the driving transistor has a source connected to a first terminal of the second storage capacitor, and a drain connected to a light emitting device;

the charging and discharging unit is connected to the data line, the first scan line, the second scan line, the power supply line, the second storage capacitor and the driving transistor, and is configured to charge the two terminals of the second storage capacitor and a gate of the driving transistor such that a voltage across the two terminals of the second storage capacitor is a voltage on the power supply line and a voltage at the gate of the driving transistor is a voltage on the data line under the control of the first and second scan lines, and to further discharge the second storage capacitor such that a voltage difference between the gate and the source of the driving transistor is a threshold voltage of the driving transistor under the control of the first and second scan lines; and

the light emitting control unit is connected to the first scan line, a second terminal of the second storage capacitor and the driving transistor, and is configured to make the driving transistor drive the light emitting device to emit light under the control of the first scan line.

3. The pixel driving circuit of claim 2, wherein the charging and discharging unit comprises:

a first transistor, a second transistor, a fourth transistor and a fifth transistor;

wherein

the first transistor has a gate connected to the second scan line, a source connected to the power supply line, and a drain connected to the first terminal of the second storage capacitor, and is configured to, under the control of the second scan line, write the voltage on the power supply line into the first terminal of the second storage capacitor, and to further disconnect the first terminal of the second storage capacitor and the power supply line, so as to discharge the voltage across the two terminals of the second storage capacitor to the voltage difference between the gate and the source of the driving transistor which is the threshold voltage of the driving transistor;

the second transistor has a gate connected to the first scan line, a source connected to the second terminal of the second storage capacitor, and a drain connected to ground, and is configured to connect the second terminal of the second storage capacitor to ground under the control of the first scan line;

the fourth transistor has a gate connected to the first scan line, a source connected to the data line, and a drain connected to the gate of the driving transistor, and is configured to set the voltage at the gate of the driving transistor to the voltage on the data line under the control of the first scan line; and

the fifth transistor has a gate connected to the first scan line, a source connected to the light emitting device, and a drain connected to ground, and is configured to shorten the light emitting device to connect the light emitting device to ground under the control of the first scan line.

4. The pixel driving circuit of claim 3, wherein the light emitting control unit comprises a third transistor, wherein

the third transistor has a gate connected to the first scan line, a source connected to the second terminal of the second storage capacitor, and a drain connected to the gate of the driving transistor, and is configured to form a path between the second terminal of the second storage capacitor and the gate of the driving transistor.

5. The pixel driving circuit of claim 4, wherein the light emitting device is an organic light emitting diode having an anode connected to the drain of the driving transistor and to the source of the fifth transistor and a cathode connected to ground.

12. An array substrate comprising the pixel driving circuit of claim 1.

13. The array substrate of claim 12, wherein the signal reading-writing unit comprises a sixth transistor having a gate connected to the second scan line, a source connected to the first terminal of the first storage capacitor, and a drain connected to the signal detecting line, and being configured to write the signal on the signal detecting line into the first terminal of the first storage capacitor, or to read out the signal stored in the first storage capacitor and transmit the same to the signal detecting line under the control of the second scan line.

14. The array substrate of claim 13, wherein the display sub-circuit comprises a second storage capacitor, a driving transistor, a charging and discharging unit, and a light emitting control unit;

wherein the driving transistor has a source connected to a first terminal of the second storage capacitor, and a drain connected to a light emitting device;

the charging and discharging unit is connected to the data line, the first scan line, the second scan line, the power supply line, the second storage capacitor and the driving transistor, and is configured to charge the two terminals of the second storage capacitor and a gate of the driving transistor such that a voltage across the two terminals of the second storage capacitor is a voltage on the power supply line and a voltage at the gate of the driving transistor is a voltage on the data line under the control of the first and second scan lines, and to further discharge the second storage capacitor such that a voltage difference between the gate and the source of the driving transistor is a threshold voltage of the driving transistor under the control of the first and second scan lines; and

the light emitting control unit is connected to the first scan line, the second terminal of the second storage capacitor and the driving transistor, and is configured to make the driving transistor drive the light emitting device to emit light under the control of the first scan line.

6. A method for driving a pixel driving circuit, wherein the pixel driving circuit comprises:

a data line, a first scan line, a second scan line, a power supply line, a light emitting device, a display sub-circuit and a photosensitive sub-circuit;

the photosensitive sub-circuit comprises;

a reference signal line, a signal detecting line, a first storage capacitor, a signal sensing unit and a signal reading-writing unit;

the method comprising;

driving the light emitting device to emit light for display by the display sub-circuit under the control of the first scan line, the second scan line, the data line and the power supply line; and

sensing a touch action by the photosensitive sub-circuit under the control of the second scan line;

wherein sensing the touch action by the photosensitive sub-circuit under the control of the second scan line comprises;

applying a second scan valid signal to the second scan line, such that the signal reading-writing unit writes the signal on the signal detecting line into a first terminal of a first storage capacitor to initialize the first terminal of the first storage capacitor;

applying a third scan valid signal to the second scan line, such that the signal sensing unit writes the signal on the reference signal line and the sensed photosensitive signal into the first storage capacitor; and

applying the second scan valid signal to the second scan line, such that the signal reading-writing unit reads out the signal stored in the first storage capacitor and transmits the same to the signal detecting line.

7. The method of claim 6, wherein

applying a second scan valid signal to the second scan line such that the signal reading-writing unit writes the signal on the signal detecting line into the first terminal of the first storage capacitor to initialize the first terminal of the first storage capacitor comprises:

applying the second scan valid signal to the second scan line, such that a sixth transistor is turned on to write the signal on the signal detecting line into the first terminal of the first storage capacitor to initialize the first terminal of the first storage capacitor; and

applying the second scan valid signal to the second scan line such that the signal reading-writing unit reads out the signal stored in the first storage capacitor and transmits the same to the signal detecting line comprises;

applying the second scan valid signal to the second scan line, such that the sixth transistor is turned on to read out the signal stored in the first storage capacitor and transmit the same to the signal detecting line.

8. The method of claim 6, wherein applying a third scan valid signal to the second scan line such that the signal sensing unit writes the signal on the reference signal line and the sensed photosensitive signal into the first storage capacitor comprises:

applying a third scan valid signal to the second scan line, such that a seventh transistor and a photosensitive transistor are turned on, wherein the seventh transistor writes the signal on the reference signal line into a second terminal of the first storage capacitor, and the photosensitive transistor writes the sensed photosensitive signal into the first terminal of the first storage capacitor.

9. The method of claim 6, wherein driving the light emitting device to emit light for display by the display sub-circuit under the control of the first scan line, the second scan line, the data line and the power supply line comprises:

applying a first scan valid signal to the first scan line and meanwhile applying the second scan valid signal to the second scan line, such that a charging and discharging unit charges the two terminals of a second storage capacitor and a gate of a driving transistor, so as to make a voltage across the two terminals of the second storage capacitor be the voltage on the power supply line and the voltage at the gate of the driving transistor be a voltage on the data line;

maintaining the first scan valid signal on the first scan line and meanwhile applying a third scan valid signal to the second scan line, such that the charging and discharging unit discharges the second storage capacitor, so as to make a voltage difference between the gate and the source of the driving transistor be a threshold voltage of the driving transistor; and

applying an invalid signal to the first scan line and meanwhile applying the second scan valid signal to the second scan line, such that a light emitting control unit forms a path between a second terminal of the second storage capacitor and the gate of the driving transistor, and that the source of the driving transistor is connected to the power supply line to drive the light emitting device to emit light.

10. The method of claim 9, wherein

applying the first scan valid signal to the first scan line and meanwhile applying the second scan valid signal to the second scan line such that the charging and discharging unit charges the two terminals of the second storage capacitor and the gate of the driving transistor so as to make the voltage across the two terminals of the second storage capacitor be the voltage on the power supply line and the voltage at the gate of the driving transistor be the voltage on the data line comprises:

applying a first scan valid signal to the first scan line and meanwhile applying the second scan valid signal to the second scan line, such that a first transistor, a second transistor, a fourth transistor and a fifth transistor are turned on, the first transistor writes the voltage on the power supply line into the first terminal of the second storage capacitor, the second transistor connects the second terminal of the second storage capacitor to ground, the fourth transistor sets the voltage at the gate of the driving transistor to the voltage on the data line, the fifth transistor shortens the light emitting device to connect the light emitting device to ground; and

maintaining the first scan valid signal on the first scan line and meanwhile applying the third scan valid signal to the second scan line such that the charging and discharging unit discharges the second storage capacitor so as to make a voltage difference between the gate and the source of the driving transistor be the threshold voltage of the driving transistor comprises;

maintaining the first scan valid signal on the first scan line and meanwhile applying the third scan valid signal to the second scan line, such that the first transistor is turned off, the second storage capacitor is discharged so as to make the voltage difference between the gate and the source of the driving transistor be the threshold voltage of the driving transistor.

11. The method of claim 10, wherein applying an invalid signal to the first scan line and meanwhile applying the second scan valid signal to the second scan line such that the light emitting control unit forms the path between the second terminal of the second storage capacitor and the gate of the driving transistor and that the source of the driving transistor is connected to the power supply line to drive the light emitting device to emit light comprises:

applying an invalid signal to the first scan line and meanwhile applying the second scan valid signal to the second scan line, so that the first transistor and a third transistor are turned on, the third transistor forms the path between the second terminal of the second storage capacitor and the gate of the driving transistor, and the first transistor connects the source of the driving transistor to the power supply line.