WO2020015337A1

WO2020015337A1 - Pixel driving circuit sensing method and pixel driving circuit

Info

Publication number: WO2020015337A1
Application number: PCT/CN2019/070042
Authority: WO
Inventors: 金羽锋
Original assignee: 深圳市华星光电半导体显示技术有限公司
Priority date: 2018-07-16
Filing date: 2019-01-02
Publication date: 2020-01-23
Also published as: CN108877611A; CN108877611B

Abstract

A pixel driving circuit sensing method and a pixel driving circuit. The pixel driving circuit sensing method comprises: in a re-writing stage (t4), a common voltage (Vcm) is firstly configured to be a second potential that is lower than a first potential, then switches to the first potential, and then is written to a second node (S); when the common voltage (Vcm) is at the second potential, a voltage on a sensing line (10) is quickly pulled down to be near the first potential due to overdrive charging; then, the common voltage (Vcm) switches to the first potential to write a correct potential to the sensing line (10), such that a time length of the re-writing stage (t4) is effectively reduced, thereby increasing a time length of a charging stage (t2), and improving the accuracy of sensing a pixel driving circuit.

Description

Pixel driving circuit sensing method and pixel driving circuit

Technical field

The present invention relates to the field of display technology, and in particular, to a pixel driving circuit sensing method and a pixel driving circuit.

Background technique

Organic Light Emitting Display (OLED) display devices have self-luminous, low driving voltage, high luminous efficiency, short response time, high definition and contrast, near 180 ° viewing angle, wide operating temperature range, and flexible display and display. Many advantages such as large-area full-color display are recognized by the industry as the most promising display devices.

OLED display devices can be divided into passive matrix OLEDs (Passive) Matrix OLED (PMOLED) and Active Matrix OLED (AMOLED) are two categories, namely direct addressing and thin film transistor (Thin Film Transistor, TFT) matrix addressing. Among them, AMOLED has pixels arranged in an array, belongs to an active display type, and has high light emission energy efficiency, and is generally used as a high-resolution large-sized display device.

AMOLED is a current-driven device. When a current flows through the organic light emitting diode, the organic light emitting diode emits light, and the light emission brightness is determined by the current flowing through the organic light emitting diode itself. Most existing integrated circuits (ICs) only transmit voltage signals, so the pixel driving circuit of AMOLED needs to complete the task of converting voltage signals into current signals. At the same time, due to the process and material characteristics of the OLED display device, a display failure (Mura) may occur during display, which needs to be sensed in real time by means of electricity in order to facilitate compensation.

Please refer to FIG. 1, which is a circuit diagram of a conventional pixel driving circuit. The pixel driving circuit includes a first thin film transistor T10, a second thin film transistor T20, a third thin film transistor T30, a capacitor C10, an organic light emitting diode D10, and a switch K10. , A sensing line 100, an analog-to-digital converter ADC, a scanning line WR, a data line DATA, and a sensing control line RD. The gate of the first thin film transistor T10 is electrically connected to the scan line WR to receive the scan signal, the source is electrically connected to the data line DATA to receive the data signal, and the drain is electrically connected to the gate of the second thin film transistor T20. The drain of the second thin film transistor T20 is connected to a positive voltage VDD, and the source is electrically connected to the anode of the organic light emitting diode D10. The gate of the third thin film transistor T30 is electrically connected to the sensing control line RD to receive a sensing signal, the source is electrically connected to the anode of the organic light emitting diode D10, and the drain is electrically connected to the sensing line 100. A first terminal of the capacitor C10 is electrically connected to a gate of the second thin film transistor T20, and a second terminal of the capacitor C10 is electrically connected to a source of the second thin film transistor T20. The cathode of the organic light emitting diode D10 is connected to a power supply negative voltage VSS. The switch K10 is a single-pole double-throw switch. The moving contact 4 is electrically connected to the sensing line 100. The first static contact 5 is connected to the common voltage VCM, and the second static contact 6 is electrically connected to the analog-to-digital converter ADC. The working process of the pixel driving circuit includes a display phase and a frame blanking phase. In the display phase, the scanning line WR transmits a scanning signal with a high-level pulse, controls the first thin film transistor T10 to turn off, and the data line DATA The display potential is written into the gate of the second thin film transistor T20, and the organic light emitting diode D10 is driven to emit light. Referring to FIG. 2, the blanking phase includes an initial phase t10, a charging phase t20, a sensing phase t30, and a rewriting phase t40. At the initial stage t10, the scanning line WR transmits a high-potential scanning signal to control the first thin-film transistor T10 to be turned on, the sensing control line RD transmits a high-potential sensing signal to control the third thin-film transistor T30 to be turned on, and the switch K10 moves it Point 4 is connected to the first static contact 5, the data line DATA writes the reference potential to the gate of the second thin film transistor T20, and the common voltage VCM is written to the source of the second thin film transistor T20. The reference potential is greater than the common voltage VCM . In the charging phase t20, the scanning line WR transmits a high-potential scanning signal to control the first thin film transistor T10 to be turned on, and the sensing control line RD transmits a high-potential sensing signal to control the third thin-film transistor T30 to be turned on, and the switch K1 moves it Point 4 is disconnected from both the first static contact 5 and the second static contact 6. At this time, the source voltage of the second thin film transistor T20, that is, the voltage on the sensing line 100 continues to rise until the source of the second thin film transistor T20. The electrode voltage and the voltage on the sensing line 100 are equal to the difference between the reference potential and the threshold voltage of the second thin film transistor T20. At the sensing stage t30, the scanning line WR transmits a low potential scanning signal to control the first thin film transistor T10 to turn off, the sensing control line RD transmits a low potential sensing signal to control the third thin film transistor T30 to turn off, and the switch K1 moves its moving contact 4 and the second static contact 6 are conducted, and the analog-to-digital converter ADC senses the voltage on the sensing line 100 and generates corresponding data and latches. In the rewriting phase t40, the scanning line WR transmits a high-potential scanning signal to control the first thin film transistor T10 to be turned on, and the sensing control line RD transmits a high-potential sensing signal to control the third thin-film transistor T30 to be turned on, and the switch K1 turns it on The moving contact 4 and the first static contact 5 are turned on, the data line DATA writes the display potential to the gate of the second thin film transistor T20, and the common voltage VCM is written to the sensing line 100. The potential of the voltage has risen with respect to the common voltage VCM. It will take a long time for the common voltage VCM to be written to the sensing line 100 to discharge the sensing line 100, so that the duration of the rewriting phase t40 is longer. The total duration of the blanking phase is very short (for a 4K display device, the total duration of the frame blanking phase is 0.68ms). The duration of the initial phase t10 is too short to be compressed, and the duration of the sensing phase t30 is limited. Since the characteristics of the analog-to-digital converter ADC cannot be changed, the length of the rewrite phase t40 is increased, so that the time of the charging phase t20 is severely compressed, resulting in insufficient charging of the sensing line 100 and inaccurate sensing results.

technical problem

An object of the present invention is to provide a pixel driving circuit sensing method, which can effectively reduce the duration of the rewriting phase, is beneficial to increase the duration of the charging phase, and improves the accuracy of sensing the pixel driving circuit.

An object of the present invention is also to provide a pixel driving circuit, which can effectively reduce the duration of the rewriting phase, is beneficial to increase the duration of the charging phase, and improves the accuracy of sensing the pixel driving circuit.

Technical solutions

To achieve the above object, the present invention provides a pixel driving circuit sensing method, including the following steps:

Step S1. A pixel driving circuit is provided. The pixel driving circuit includes a first thin film transistor (T1), a second thin film transistor (T2), a third thin film transistor (T3), a capacitor (C1), and an organic light emitting diode (D1). , Switch (K1), sensing line (10), sensing module (20), data line (Data), scanning line (WR) and sensing control line (RD);

The gate of the first thin film transistor (T1) is electrically connected to the scan line (WR), the source is electrically connected to the data line (Data), and the drain is electrically connected to the first node (G); the second thin film transistor The gate of (T2) is electrically connected to the first node (G), the drain is electrically connected to the positive voltage (VDD), and the source is electrically connected to the second node (S); the gate of the third thin film transistor (T3) The electrode is electrically connected to the sensing control line (RD), the source is electrically connected to the second node (S), and the drain is electrically connected to the sense line (10); the first end and the second end of the capacitor (C1) The first node (G) and the second node (S) are electrically connected respectively; the anode of the organic light emitting diode (D1) is electrically connected to the second node (S), and the cathode is connected to a negative voltage (VSS); The switch (K1) is a single-pole double-throw switch. The moving contact (1) is electrically connected to the sensing line (10), the first static contact (2) is connected to a common voltage (Vcm), and the second static contact (3) ) Electrically connect the sensing module (20);

Step S2, enter the initial stage (t1);

The scanning line (WR) transmits the scanning signal to control the first thin film transistor (T1) to be turned on, the sensing control line (RD) transmits the sensing signal to control the third thin film transistor (T3) to be turned on, and the switch (K1) turns its moving contact (1) Conducting with the first static contact (2), the data line (Data) writes the reference potential to the first node (G), and the common voltage (Vcm) is a first potential writing to the sensing line (10) And the second node (S); the reference potential is greater than the first potential;

Step S3: Enter the charging phase (t2);

The scanning line (WR) transmits the scanning signal to control the first thin film transistor (T1) to be turned on, the sensing control line (RD) transmits the sensing signal to control the third thin film transistor (T3) to be turned on, and the switch (K1) turns its moving contact (1) Disconnect from both the first static contact (2) and the second static contact (3), the data line (Data) writes the reference potential to the first node (G), and the positive power supply voltage (VDD) is the first The two nodes (S) and the sensing line (10) are charged, so that the voltage on the second node (S) and the sensing line (10) continues to rise until the voltage of the second node (S) and the sensing line (10) Equal to the difference between the reference potential and the threshold voltage of the second thin film transistor (T2);

Step S4: Enter the sensing phase (t3);

The scanning line (WR) transmits a scanning signal to control the first thin film transistor (T1) to turn off, the sensing control line (RD) transmits a sensing signal to control the third thin film transistor (T3) to turn off, and the switch (K1) moves its moving contact (1 ) Is in conduction with the second static contact (3), and the sensing module (20) senses the voltage on the sensing line (10);

Step S5: Enter a rewrite phase (t4);

The scanning line (WR) transmits the scanning signal to control the first thin film transistor (T1) to be turned on, the sensing control line (RD) transmits the sensing signal to control the third thin film transistor (T3) to be turned on, and the switch (K1) turns its moving contact (1) Connected with the first static contact (2), the data line (Data) writes the display potential to the first node (G), the common voltage (Vcm) is first a second potential, and then switches to the first potential and Write the sensing line (10) and the second node (S), and pull down the potentials of the sensing line (10) and the second node (S) to a first potential; the second potential is smaller than the first potential;

In step S2, step S3, and step S5, the scanning line (WR) transmits a high-potential scanning signal, and the sensing control line (RD) transmits a high-potential sensing signal; in step S4, the scanning line (WR) A low-potential scanning signal is transmitted, and a low-potential sensing signal is transmitted by the sensing control line (RD); and in the steps S3 and S4, the common voltage (Vcm) is a first potential.

In step S5, the specific method for switching the common voltage (Vcm) from the second potential to the first potential is: the common voltage (Vcm) is first switched from the second potential to a plurality of intermediate potentials in sequence, and then from the last One intermediate potential is switched to the first potential; among the multiple intermediate potentials, the odd-numbered intermediate potential is greater than the first potential, the even-numbered intermediate potential is smaller than the first potential, and the absolute values of the differences between the multiple intermediate potentials and the first potential are sequentially decreased. And the difference between the first intermediate potential and the first potential is smaller than the difference between the first potential and the second potential.

The pixel driving circuit further includes a voltage modulation module (30) electrically connected to the first static contact (2) of the switch (K1); the common voltage (Vcm) is provided by the voltage modulation module (30).

When the voltage modulation module (30) changes the potential of the common voltage (Vcm), the time interval between any two neighboring common voltage (Vcm) potential change moments is on the order of nanoseconds.

The pixel driving circuit further includes a circuit board (40), and the voltage modulation module (30) is disposed on the circuit board (40).

The first potential is 4 volts (V) and the second potential is 1 volt (V).

The sensing module (20) is an analog-to-digital converter (ADC);

In step S4, after the analog-to-digital converter (ADC) senses the voltage on the sensing line (10), it also performs analog-to-digital conversion processing on the voltage on the sensing line (10) to generate corresponding data and lock it. Save.

To achieve the above object, the present invention further provides a pixel driving circuit sensing method, including the following steps:

Step S1. A pixel driving circuit is provided. The pixel driving circuit includes a first thin film transistor, a second thin film transistor, a third thin film transistor, a capacitor, an organic light emitting diode, a switch, a sensing line, a sensing module, a data line, and a scan. Line and sensing control line;

The gate of the first thin film transistor is electrically connected to the scan line, the source is electrically connected to the data line, and the drain is electrically connected to the first node; the gate of the second thin film transistor is electrically connected to the first node and the drain Connect the positive voltage of the power source, the source is electrically connected to the second node; the gate of the third thin film transistor is electrically connected to the sensing control line, the source is electrically connected to the second node, and the drain is electrically connected to the sensing line; The first end and the second end of the capacitor are electrically connected to the first node and the second node, respectively; the anode of the organic light emitting diode is electrically connected to the second node, and the cathode is connected to the negative voltage of the power source; the switch is single-pole double Throw switch, whose moving contact is electrically connected to the sensing line, the first static contact is connected to the common voltage, and the second static contact is electrically connected to the sensing module;

Step S2, enter the initial stage;

The scan line transmits the scanning signal to control the first thin film transistor to be turned on, the sensing control line transmits the sensing signal to control the third thin film transistor to be turned on, the switch turns its moving contact to the first static contact, and the data line writes the reference potential Into the first node, the common voltage is a first potential write sensing line and the second node; the reference potential is greater than the first potential;

Step S3: Enter the charging phase;

The scanning line transmits a scanning signal to control the first thin film transistor to be turned on, the sensing control line transmits a sensing signal to control the third thin film transistor to be turned on, and the switch disconnects its moving contact from the first static contact and the second static contact The data line writes the reference potential to the first node, and the positive voltage of the power source charges the second node and the sensing line, so that the voltage on the second node and the sensing line continues to rise until the voltage of the second node and the sensing line is equal to A difference between a reference potential and a threshold voltage of the second thin film transistor;

Step S4: Enter the sensing stage;

The scanning line transmits a scanning signal to control the first thin film transistor to be turned off, the sensing control line transmits a sensing signal to control the third thin film transistor to be turned off, the switch connects its moving contact with the second static contact, and the sensing module connects the sensing line Sensing voltage;

Step S5: Enter the rewrite phase;

The scanning line transmits the scanning signal to control the first thin film transistor to be turned on, the sensing control line transmits the sensing signal to control the third thin film transistor to be turned on, the switch connects its moving contact with the first static contact, and the data line will write the display potential After entering the first node, the common voltage is first a second potential and then switched to the first potential and written to the sensing line and the second node, and the potentials of the sensing line and the second node are pulled down to the first potential; the second The potential is less than the first potential.

In step S5, the specific method of switching the common voltage from the second potential to the first potential is: the common voltage is first switched from the second potential to a plurality of intermediate potentials in order, and then the last intermediate potential is switched to the first potential. One potential; the odd-numbered intermediate potential is greater than the first potential, the even-numbered intermediate potential is smaller than the first potential, the absolute value of the difference between the plurality of intermediate potentials and the first potential decreases in sequence, and the first The difference between the intermediate potential and the first potential is smaller than the difference between the first potential and the second potential.

The pixel driving circuit further includes a voltage modulation module electrically connected to the first static contact of the switch; the common voltage is provided by the voltage modulation module.

When the voltage modulation module changes the potential of the common voltage, the time interval between any two adjacent moments of the change of the common voltage potential is on the order of nanoseconds.

The pixel driving circuit further includes a circuit board, and the voltage modulation module is disposed on the circuit board.

In step S2, step S3, and step S5, the scanning line transmits a scanning signal with a high potential, and the sensing control line transmits a sensing signal with a high potential;

In step S4, the scanning line transmits a scanning signal with a low potential, and the sensing control line transmits a sensing signal with a low potential.

The first potential is 4V and the second potential is 1V.

The sensing module is an analog-to-digital converter;

In step S4, after the analog-to-digital converter senses the voltage on the sensing line, it also performs analog-to-digital conversion processing on the voltage on the sensing line to generate corresponding data and latch it.

In step S3 and step S4, the common voltage is the first potential.

The invention also provides a pixel driving circuit, which includes a first thin film transistor, a second thin film transistor, a third thin film transistor, a capacitor, an organic light emitting diode, a switch, a sensing line, a sensing module, a data line, a scanning line, and a sensing device. Control line and voltage modulation module;

The gate of the first thin film transistor is electrically connected to the scan line, the source is electrically connected to the data line, and the drain is electrically connected to the first node; the gate of the second thin film transistor is electrically connected to the first node and the drain Connect the positive voltage of the power source, the source is electrically connected to the second node; the gate of the third thin film transistor is electrically connected to the sensing control line, the source is electrically connected to the second node, and the drain is electrically connected to the sensing line; The first end and the second end of the capacitor are electrically connected to the first node and the second node, respectively; the anode of the organic light emitting diode is electrically connected to the second node, and the cathode is connected to the negative voltage of the power source; the switch is single-pole double Throw switch, whose moving contact is electrically connected to the sensing line, the first static contact is electrically connected to the voltage modulation module, and the second static contact is electrically connected to the sensing module;

The voltage modulation module is used to output a common voltage to the first static contact. In the rewriting phase, the voltage modulation module makes the common voltage first a second potential and switches from the second potential to a plurality of intermediate potentials in sequence. The last intermediate potential is switched to the first potential; the second potential is smaller than the first potential, the odd-numbered intermediate potentials of the plurality of intermediate potentials are larger than the first potential, the even-numbered intermediate potentials are smaller than the first potential, and the plurality of intermediate potentials are The absolute value of the difference between the first potential decreases sequentially, and the difference between the first intermediate potential and the first potential is smaller than the difference between the first potential and the second potential.

Beneficial effect

Beneficial effects of the present invention: In the pixel driving circuit sensing method provided by the present invention, in the rewriting phase, the common voltage is first set to a second potential lower than the first potential, and then switched to the first potential and written to the second potential. Node, when the common voltage is at the second potential, the voltage on the sensing line will be quickly pulled down to close to the first potential due to overdrive charging, and then the common voltage is switched to the first potential to write the correct potential to the sensing line , Can effectively reduce the length of the rewrite phase, is beneficial to increase the length of the charging phase, and improve the accuracy of sensing the pixel driving circuit. The pixel driving circuit of the present invention can effectively reduce the duration of the rewrite phase, is beneficial to increase the duration of the charging phase, and improves the accuracy of sensing the pixel driving circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to further understand the features and technical contents of the present invention, please refer to the following detailed description of the present invention and the accompanying drawings, but the drawings are provided for reference and explanation only, and are not intended to limit the present invention.

In the drawings,

FIG. 1 is a circuit diagram of a conventional pixel driving circuit;

2 is a timing diagram of the pixel driving circuit shown in FIG. 1 during a frame blanking stage;

3 is a flowchart of a pixel driving circuit sensing method of the present invention;

4 is a circuit diagram of a pixel driving circuit according to a first embodiment of the pixel driving circuit sensing method of the present invention;

5 is a timing diagram of a first embodiment of a sensing method of a pixel driving circuit according to the present invention;

6 is a circuit diagram of a pixel driving circuit according to a second embodiment of the pixel driving circuit sensing method of the present invention and a circuit diagram of a pixel driving circuit of the present invention;

FIG. 7 is a timing diagram of a pixel driving circuit sensing method according to a second embodiment of the present invention.

Best Mode of the Invention

In order to further explain the technical means adopted by the present invention and its effects, the following describes in detail with reference to the preferred embodiments of the present invention and the accompanying drawings.

Referring to FIG. 3 to FIG. 5, the first embodiment of the pixel driving circuit sensing method of the present invention includes the following steps:

Step S1, please refer to FIG. 4, and provide a pixel driving circuit. The pixel driving circuit includes a first thin film transistor T1, a second thin film transistor T2, a third thin film transistor T3, a capacitor C1, an organic light emitting diode D1, a switch K1, a sensing line 10, a sensing module 20, a data line Data, and a scan. Line WR and sensing control line RD. The gate of the first thin film transistor T1 is electrically connected to the scan line WR, the source is electrically connected to the data line Data, and the drain is electrically connected to the first node G. The gate of the second thin film transistor T2 is electrically connected to the first node G, the drain is electrically connected to the positive voltage VDD, and the source is electrically connected to the second node S. The gate of the third thin film transistor T3 is electrically connected to the sensing control line RD, the source is electrically connected to the second node S, and the drain is electrically connected to the sensing line 10. The first end and the second end of the capacitor C1 are electrically connected to the first node G and the second node S, respectively. The anode of the organic light emitting diode D1 is electrically connected to the second node S, and the cathode is connected to the negative voltage VSS of the power source. The switch K1 is a single-pole double-throw switch. The moving contact 1 is electrically connected to the sensing line 10, the first static contact 2 is connected to a common voltage Vcm, and the second static contact 3 is electrically connected to the sensing module 20.

Specifically, referring to FIG. 4, the sensing module 20 is an analog-to-digital converter ADC.

Step S2, enter the initial stage t1.

The scanning line WR transmits a scanning signal to control the first thin film transistor T1 to be turned on, the sensing control line RD transmits a sensing signal to control the third thin film transistor T3 to be turned on, and the switch K1 turns on its moving contact 1 and the first static contact 2 The data line Data writes the reference potential to the first node G via the first thin film transistor T1 that is turned on, and the common voltage Vcm is written to the sensing line 10 as a first potential and is written to the third node through the third thin film transistor T3 that is turned on. Two nodes S complete the initialization of the potentials of the first node G and the second node S. The reference potential is greater than the first potential.

Specifically, referring to FIG. 5, in step S2, the scanning line WR transmits a high-potential scanning signal to control the first thin film transistor T1 to be turned on, and the sensing control line RD transmits a high-potential sensing signal to control the third thin film transistor T3. Continuity.

Preferably, the first potential is 4V.

Preferably, the high potentials of the scanning signal and the sensing signal are both 25V.

Step S3: Enter the charging phase t2.

The scanning line WR transmits a scanning signal to control the first thin film transistor T1 to be turned on, the sensing control line RD transmits a sensing signal to control the third thin film transistor T3 to be turned on, and the switch K1 turns its moving contact 1 and the first static contact 2 and the first The two static contacts 3 are both opened, and the data line Data writes the reference potential to the first node G. At this time, the second thin film transistor T2 is turned on, and the positive voltage of the power source VDD is charged for the second node S. The three thin film transistors T3 charge the sensing line 10, so that the voltage on the second node S and the sensing line 10 continues to increase until the voltage of the second node S and the sensing line 10 is equal to the reference potential and the threshold voltage of the second thin film transistor T2. The difference is complete and charging is completed.

Specifically, referring to FIG. 5, in step S3, the scanning line WR transmits a high-potential scanning signal to control the first thin film transistor T1 to be turned on, and the sensing control line RD transmits a high-potential sensing signal to control the second thin film transistor T2. Continuity.

Specifically, referring to FIG. 5, in step S3, the common voltage Vcm is maintained at a first potential.

Step S4: Enter the sensing phase t3.

The scanning line WR transmits a scanning signal to control the first thin film transistor T1 to be turned off, and the sensing control line RD transmits a sensing signal to control the third thin film transistor T3 to be turned off. The switch K1 turns on its moving contact 1 and the second static contact 3, and the sensing The detecting module 20 senses the voltage on the sensing line 10.

Specifically, referring to FIG. 5, in the step S4, the scan line WR transmits a scan signal of a low potential to control the first thin film transistor T1 to be turned off, and the scan control line RD transmits a scan signal of a low potential to control the third thin film transistor T3 to be turned off. .

Preferably, the low potentials of the scanning signal and the sensing signal are both -5V.

Specifically, referring to FIG. 5, in step S4, the common voltage Vcm is maintained at a first potential.

Specifically, in step S4, after the analog-to-digital converter ADC senses the voltage on the sensing line 10, it also performs analog-to-digital conversion processing on the voltage on the sensing line 10 to generate corresponding data and latch it.

Step S5: Enter a rewrite phase t4.

The scanning line WR transmits a scanning signal to control the first thin film transistor T1 to be turned on, the sensing control line RD transmits a sensing signal to control the third thin film transistor T3 to be turned on, and the switch K1 turns on its moving contact 1 and the first static contact 2 The data line Data writes the display potential to the first node G via the turned-on first thin-film transistor T1, and the common voltage Vcm is firstly a second potential, and then switched to the first potential and written to the sensing line 10, and is turned on The third thin film transistor T3 is written into the second node S. In this process, the common voltage Vcm discharges the voltage on the sensing line 10, and the potentials of the sensing line 10 and the second node S are pulled down to the first potential. The second potential is smaller than the first potential.

Specifically, referring to FIG. 5, in step S5, the scanning line WR transmits a high-potential scanning signal to control the first thin film transistor T1 to be turned on, and the sensing control line RD transmits a high-potential sensing signal to control the second thin-film transistor T2 to be turned on. .

Specifically, referring to FIG. 5, in the first embodiment of the present invention, in step S5, the common voltage Vcm is firstly the second potential and then is switched to the first potential directly.

Preferably, the second potential is 1V.

It should be noted that, in the first embodiment of the present invention, in the rewriting phase t4, the common voltage Vcm is first set to a second potential smaller than the first potential. At this time, the voltage on the sensing line 10 may be overdriven ( Over Drive) is charged and is quickly pulled down to near the first potential, and then the common voltage Vcm is directly switched from the second potential to the first potential, and the correct potential writing is performed on the sensing line 10 and the second node S, compared with the current It is technically possible that the time taken for the sensing line 10 to discharge to the first potential is greatly shortened, which can effectively reduce the duration of the rewriting phase t4. The total duration of the initial phase t1, the charging phase t2, the sensing phase t3, and the rewriting phase t4 Under the limited premise, it is beneficial to increase the duration of the charging phase t2 and improve the accuracy of sensing the pixel driving circuit.

Please refer to FIG. 3, FIG. 6 and FIG. 7. The difference between the second embodiment of the pixel driving circuit sensing method of the present invention and the above-mentioned first embodiment is as follows: Referring to FIG. 7, in step S5, the common voltage A specific manner of switching Vcm from the second potential to the first potential is: the common voltage Vcm is first switched from the second potential to a plurality of intermediate potentials in order, and then the last intermediate potential is switched to the first potential. Among the plurality of intermediate potentials, the odd-numbered intermediate potential is greater than the first potential, the even-numbered intermediate potential is smaller than the first potential, the absolute value of the difference between the plurality of intermediate potentials and the first potential decreases in sequence, and the first intermediate potential and The difference between the first potential is smaller than the difference between the first potential and the second potential.

Specifically, referring to FIG. 6, in a second embodiment of the present invention, the pixel driving circuit further includes a voltage modulation module 30 and a circuit board (PCB) 40 electrically connected to the first static contact 2 of the switch K1. . The common voltage Vcm is provided by the voltage modulation module 30. The voltage modulation module 30 is disposed on the circuit board 40.

Further, when the voltage modulation module 30 changes the potential of the common voltage Vcm, the time interval between any two adjacent common voltage Vcm potential change moments is in the nanosecond level, that is, the voltage adjustment module 30 can The voltage Vcm performs potential switching at the nanosecond level. Furthermore, in the second embodiment of the present invention, the second potential and the duration of each intermediate potential are both at the nanosecond level.

Preferably, referring to FIG. 7, the durations of the plurality of intermediate potentials are sequentially reduced, and the duration of the first intermediate potential is less than the duration of the second potential.

It should be noted that in the second embodiment of the present invention, a voltage modulation module 30 capable of nanosecond level potential switching is used to provide a common voltage Vcm to the first static contact 2 of the switch K1, and in the rewriting phase t4, The common voltage Vcm is first a second potential smaller than the first potential, and then the common voltage Vcm is switched from the second potential to a plurality of intermediate potentials in order, and then the last intermediate potential is switched to the first potential. The two nodes S perform correct potential writing. When the potential of the common voltage Vcm is lower than the first potential each time, the voltage on the sensing line 10 will be rapidly pulled down due to overdriving and charging. The voltage is quickly pulled down to the first potential. Compared with the prior art, the time for the sensing line 10 to discharge to the first potential is greatly shortened, which can effectively reduce the length of the rewrite phase t4. In the initial phase t1 and the charging phase t2 On the premise that the total duration of the sensing phase t3 and the rewriting phase t4 is limited, it is beneficial to increase the duration of the charging phase t2 and improve the accuracy of the pixel driving circuit sensing.

Please refer to FIG. 6. Based on the same inventive concept, the present invention further provides a pixel driving circuit, which includes a first thin film transistor T1, a second thin film transistor T2, a third thin film transistor T3, a capacitor C1, an organic light emitting diode D1, a switch K1, The sensing line 10, the sensing module 20, the data line Data, the scanning line WR, the sensing control line RD, and the voltage modulation module 30.

The gate of the first thin film transistor T1 is electrically connected to the scan line WR, the source is electrically connected to the data line Data, and the drain is electrically connected to the first node G. The gate of the second thin film transistor T2 is electrically connected to the first node G, the drain is electrically connected to the positive voltage VDD, and the source is electrically connected to the second node S. The gate of the third thin film transistor T3 is electrically connected to the sensing control line RD, the source is electrically connected to the second node S, and the drain is electrically connected to the sensing line 10. The first end and the second end of the capacitor C1 are electrically connected to the first node G and the second node S, respectively. The anode of the organic light emitting diode D1 is electrically connected to the second node S, and the cathode is connected to the negative voltage VSS of the power source. The switch K1 is a single-pole double-throw switch. The moving contact 1 is electrically connected to the sensing line 10, the first static contact 2 is electrically connected to the voltage modulation module 30, and the second static contact 3 is electrically connected to the sensing module 20. .

The voltage modulation module 30 is configured to output a common voltage Vcm to the first stationary contact 2. In the rewriting phase, the voltage modulation module 30 causes the common voltage Vcm to be a second potential, and then switches from the second potential to a plurality of intermediate potentials in sequence, and then switches from the last intermediate potential to the first potential. The second potential is less than the first potential, the odd-numbered intermediate potentials of the plurality of intermediate potentials are greater than the first potential, the even-numbered intermediate potentials are less than the first potential, and the absolute values of the differences between the plurality of intermediate potentials and the first potential are in order Decreases, and the difference between the first intermediate potential and the first potential is smaller than the difference between the first potential and the second potential.

Specifically, referring to FIG. 6, the pixel driving circuit further includes a circuit board 40. The voltage modulation module 30 is disposed on the circuit board 40.

Specifically, when the voltage modulation module 30 changes the potential of the common voltage Vcm, the time interval between any two adjacent common voltage Vcm potential change moments is in the nanosecond level, that is, the voltage adjustment module 30 can The voltage Vcm performs potential switching at the nanosecond level, and in the rewriting phase, the second potential and the duration of each intermediate potential are both at the nanosecond level.

Specifically, in conjunction with FIG. 6 and FIG. 7, the working process of the pixel driving circuit of the present invention is as follows:

First, the initial phase t1 is entered. The scanning line WR transmits a scanning signal to control the first thin film transistor T1 to be turned on, the sensing control line RD transmits a sensing signal to control the third thin film transistor T3 to be turned on, and the switch K1 turns on its moving contact 1 and the first static contact 2 The data line Data writes the reference potential to the first node G via the first thin film transistor T1 that is turned on, and the common voltage Vcm is written to the sensing line 10 as a first potential and is written to the third node through the third thin film transistor T3 that is turned on. Two nodes S complete the initialization of the potentials of the first node G and the second node S. The reference potential is greater than the first potential.

Then, it enters a charging phase t2. The scanning line WR transmits a scanning signal to control the first thin film transistor T1 to be turned on, the sensing control line RD transmits a sensing signal to control the third thin film transistor T3 to be turned on, and the switch K1 turns its moving contact 1 and the first static contact 2 and the first The two static contacts 3 are both opened, and the data line Data writes the reference potential to the first node G. At this time, the second thin film transistor T2 is turned on, and the positive voltage of the power source VDD is charged for the second node S. The three thin film transistors T3 charge the sensing line 10, so that the voltage on the second node S and the sensing line 10 continues to increase until the voltage of the second node S and the sensing line 10 is equal to the reference potential and the threshold voltage of the second thin film transistor T2. The difference is complete and charging is completed.

After that, it enters the sensing phase t3. The scanning line WR transmits a scanning signal to control the first thin film transistor T1 to be turned off, and the sensing control line RD transmits a sensing signal to control the third thin film transistor T3 to be turned off. The switch K1 turns on its moving contact 1 and the second static contact 3, and the sensing The detecting module 20 senses the voltage on the sensing line 10.

Then, it enters a rewrite phase t4. The scanning line WR transmits a scanning signal to control the first thin film transistor T1 to be turned on, the sensing control line RD transmits a sensing signal to control the third thin film transistor T3 to be turned on, and the switch K1 turns on its moving contact 1 and the first static contact 2 The data line Data writes the display potential to the first node G via the turned-on first thin-film transistor T1, and the common voltage Vcm is firstly a second potential, and then switched to the first potential and written to the sensing line 10, and is turned on The third thin film transistor T3 is written into the second node S. In this process, the common voltage Vcm discharges the voltage on the sensing line 10, and the potentials of the sensing line 10 and the second node S are pulled down to the first potential. The second potential is smaller than the first potential.

It should be noted that the pixel driving circuit of the present invention uses a voltage modulation module 30 capable of nanosecond level potential switching during operation to provide a common voltage Vcm to the first static contact 2 of the switch K1, and in the rewriting phase t4, The common voltage Vcm is first a second potential smaller than the first potential, and then the common voltage Vcm is switched from the second potential to a plurality of intermediate potentials in order, and then the last intermediate potential is switched to the first potential. The two nodes S perform correct potential writing. When the potential of the common voltage Vcm is lower than the first potential each time, the voltage on the sensing line 10 will be rapidly pulled down due to overdriving and charging. The voltage is quickly pulled down to the first potential. Compared with the prior art, the time for the sensing line 10 to discharge to the first potential is greatly shortened, which can effectively reduce the length of the rewrite phase t4. In the initial phase t1 and the charging phase t2 On the premise that the total duration of the sensing phase t3 and the rewriting phase t4 is limited, it is beneficial to increase the duration of the charging phase t2 and improve the accuracy of the pixel driving circuit sensing.

In summary, in the pixel driving circuit sensing method of the present invention, in the rewriting phase, the common voltage is first set to a second potential lower than the first potential, and then switched to the first potential and written to the second node. When the voltage is at the second potential, the voltage on the sensing line will be quickly pulled down to close to the first potential due to overdrive charging, and then the common voltage is switched to the first potential to write the correct potential to the sensing line, which can effectively reduce The length of the rewrite phase is beneficial to increase the length of the charging phase and improve the accuracy of sensing the pixel driving circuit. The pixel driving circuit of the present invention can effectively reduce the duration of the rewrite phase, is beneficial to increase the duration of the charging phase, and improves the accuracy of sensing the pixel driving circuit.

As described above, for a person of ordinary skill in the art, various other corresponding changes and modifications can be made according to the technical solutions and technical concepts of the present invention, and all these changes and deformations should fall within the protection scope of the claims of the present invention. .

Claims

A pixel driving circuit sensing method includes the following steps:

Step S1. A pixel driving circuit is provided. The pixel driving circuit includes a first thin film transistor, a second thin film transistor, a third thin film transistor, a capacitor, an organic light emitting diode, a switch, a sensing line, a sensing module, a data line, and a scan. Line and sensing control line;

The gate of the first thin film transistor is electrically connected to the scan line, the source is electrically connected to the data line, and the drain is electrically connected to the first node; the gate of the second thin film transistor is electrically connected to the first node and the drain Connect the positive voltage of the power source, the source is electrically connected to the second node; the gate of the third thin film transistor is electrically connected to the sensing control line, the source is electrically connected to the second node, and the drain is electrically connected to the sensing line; The first end and the second end of the capacitor are electrically connected to the first node and the second node, respectively; the anode of the organic light emitting diode is electrically connected to the second node, and the cathode is connected to the negative voltage of the power source; the switch is single-pole double Throw switch, whose moving contact is electrically connected to the sensing line, the first static contact is connected to the common voltage, and the second static contact is electrically connected to the sensing module;

Step S2, enter the initial stage;

The scan line transmits the scanning signal to control the first thin film transistor to be turned on, the sensing control line transmits the sensing signal to control the third thin film transistor to be turned on, the switch turns its moving contact to the first static contact, and the data line writes the reference potential Into the first node, the common voltage is a first potential write sensing line and the second node; the reference potential is greater than the first potential;

Step S3: Enter the charging phase;

The scanning line transmits a scanning signal to control the first thin film transistor to be turned on, the sensing control line transmits a sensing signal to control the third thin film transistor to be turned on, and the switch disconnects its moving contact from the first static contact and the second static contact The data line writes the reference potential to the first node, and the positive voltage of the power source charges the second node and the sensing line, so that the voltage on the second node and the sensing line continues to rise until the voltage of the second node and the sensing line is equal to A difference between a reference potential and a threshold voltage of the second thin film transistor;

Step S4: Enter the sensing stage;

The scanning line transmits a scanning signal to control the first thin film transistor to be turned off, the sensing control line transmits a sensing signal to control the third thin film transistor to be turned off, the switch connects its moving contact with the second static contact, and the sensing module connects the sensing line Sensing voltage;

Step S5: Enter the rewrite phase;

The scanning line transmits the scanning signal to control the first thin film transistor to be turned on, the sensing control line transmits the sensing signal to control the third thin film transistor to be turned on, the switch connects its moving contact with the first static contact, and the data line will write the display potential After entering the first node, the common voltage is first a second potential and then switched to the first potential and written into the sensing line (10) and the second node, and the potentials of the sensing line and the second node are pulled down to the first potential; Said second potential is less than the first potential;

In step S2, step S3, and step S5, the scanning line transmits a high-potential scanning signal, and the sensing control line transmits a high-potential sensing signal; in step S4, the scanning line transmits a low-potential scanning signal to sense The control line transmits a low-potential sensing signal; and in the steps S3 and S4, the common voltage is a first potential.
The sensing method of a pixel driving circuit according to claim 1, wherein in the step S5, the specific method of switching the common voltage from the second potential to the first potential is: the common voltage is sequentially switched from the second potential first Switch to multiple intermediate potentials, and then switch from the last intermediate potential to the first potential; among the multiple intermediate potentials, the odd-numbered intermediate potential is greater than the first potential, and the even-numbered intermediate potential is less than the first potential; The absolute value of the difference between a potential decreases in order, and the difference between the first intermediate potential and the first potential is smaller than the difference between the first potential and the second potential.
The sensing method of a pixel driving circuit according to claim 2, wherein the pixel driving circuit further comprises a voltage modulation module electrically connected to the first static contact of the switch; the common voltage is provided by the voltage modulation module .
The sensing method of a pixel driving circuit according to claim 3, wherein when the voltage modulation module changes the potential of the common voltage, a time interval between any two adjacent moments of the change of the common voltage potential is on the order of nanoseconds.
The sensing method of a pixel driving circuit according to claim 3, wherein the pixel driving circuit further comprises a circuit board, and the voltage modulation module is disposed on the circuit board.
The sensing method of a pixel driving circuit according to claim 1, wherein the first potential is 4 volts and the second potential is 1 volt.
The sensing method of a pixel driving circuit according to claim 1, wherein the sensing module is an analog-to-digital converter;

In step S4, after the analog-to-digital converter senses the voltage on the sensing line, it also performs analog-to-digital conversion processing on the voltage on the sensing line to generate corresponding data and latch it.
A pixel driving circuit sensing method includes the following steps:

Step S1. A pixel driving circuit is provided. The pixel driving circuit includes a first thin film transistor, a second thin film transistor, a third thin film transistor, a capacitor, an organic light emitting diode, a switch, a sensing line, a sensing module, a data line, and a scan. Line and sensing control line;

The gate of the first thin film transistor is electrically connected to the scan line, the source is electrically connected to the data line, and the drain is electrically connected to the first node; the gate of the second thin film transistor is electrically connected to the first node and the drain Connect the positive voltage of the power source, the source is electrically connected to the second node; the gate of the third thin film transistor is electrically connected to the sensing control line, the source is electrically connected to the second node, and the drain is electrically connected to the sensing line; The first end and the second end of the capacitor are electrically connected to the first node and the second node, respectively; the anode of the organic light emitting diode is electrically connected to the second node, and the cathode is connected to the negative voltage of the power source; the switch is single-pole double Throw switch, whose moving contact is electrically connected to the sensing line, the first static contact is connected to the common voltage, and the second static contact is electrically connected to the sensing module;

Step S2, enter the initial stage;

The scan line transmits the scanning signal to control the first thin film transistor to be turned on, the sensing control line transmits the sensing signal to control the third thin film transistor to be turned on, the switch turns its moving contact to the first static contact, and the data line writes the reference potential Into the first node, the common voltage is a first potential write sensing line and the second node; the reference potential is greater than the first potential;

Step S3: Enter the charging phase;

The scanning line transmits a scanning signal to control the first thin film transistor to be turned on, the sensing control line transmits a sensing signal to control the third thin film transistor to be turned on, and the switch disconnects its moving contact from the first static contact and the second static contact The data line writes the reference potential to the first node, and the positive voltage of the power source charges the second node and the sensing line, so that the voltage on the second node and the sensing line continues to rise until the voltage of the second node and the sensing line is equal to A difference between a reference potential and a threshold voltage of the second thin film transistor;

Step S4: Enter the sensing stage;

The scanning line transmits a scanning signal to control the first thin film transistor to be turned off, the sensing control line transmits a sensing signal to control the third thin film transistor to be turned off, the switch connects its moving contact with the second static contact, and the sensing module connects the sensing line Sensing voltage;

Step S5: Enter the rewrite phase;

The scanning line transmits the scanning signal to control the first thin film transistor to be turned on, the sensing control line transmits the sensing signal to control the third thin film transistor to be turned on, the switch connects its moving contact with the first static contact, and the data line will write the display potential After entering the first node, the common voltage is first a second potential and then switched to the first potential and written to the sensing line and the second node, and the potentials of the sensing line and the second node are pulled down to the first potential; the second The potential is less than the first potential.
The sensing method of a pixel driving circuit according to claim 8, wherein in the step S5, the specific method of switching the common voltage from the second potential to the first potential is: the common voltage is sequentially switched from the second potential first Switch to multiple intermediate potentials, and then switch from the last intermediate potential to the first potential; among the multiple intermediate potentials, the odd-numbered intermediate potential is greater than the first potential, and the even-numbered intermediate potential is less than the first potential; The absolute value of the difference between a potential decreases in order, and the difference between the first intermediate potential and the first potential is smaller than the difference between the first potential and the second potential.
The sensing method of a pixel driving circuit according to claim 9, wherein the pixel driving circuit further comprises a voltage modulation module electrically connected to the first static contact of the switch; the common voltage is provided by the voltage modulation module .
The sensing method of the pixel driving circuit according to claim 10, wherein when the voltage modulation module changes the potential of the common voltage, a time interval between any two adjacent moments of the change of the common voltage potential is in the nanosecond level.
The sensing method of a pixel driving circuit according to claim 10, wherein the pixel driving circuit further comprises a circuit board, and the voltage modulation module is disposed on the circuit board.
The sensing method of a pixel driving circuit according to claim 8, wherein in the step S2, step S3, and step S5, the scanning line transmits a high-potential scanning signal, and the sensing control line transmits a high-potential sensing signal;

In step S4, the scanning line transmits a scanning signal with a low potential, and the sensing control line transmits a sensing signal with a low potential.
The sensing method of a pixel driving circuit according to claim 8, wherein the first potential is 4 volts and the second potential is 1 volt.
The sensing method of a pixel driving circuit according to claim 8, wherein the sensing module is an analog-to-digital converter;

In step S4, after the analog-to-digital converter senses the voltage on the sensing line, it also performs analog-to-digital conversion processing on the voltage on the sensing line to generate corresponding data and latch it.
The sensing method of the pixel driving circuit according to claim 8, wherein in step S3 and step S4, the common voltage is a first potential.
A pixel driving circuit includes a first thin film transistor, a second thin film transistor, a third thin film transistor, a capacitor, an organic light emitting diode, a switch, a sensing line, a sensing module, a data line, a scanning line, a sensing control line, and Voltage modulation module;

The gate of the first thin film transistor is electrically connected to the scan line, the source is electrically connected to the data line, and the drain is electrically connected to the first node; the gate of the second thin film transistor is electrically connected to the first node and the drain Connect the positive voltage of the power source, the source is electrically connected to the second node; the gate of the third thin film transistor is electrically connected to the sensing control line, the source is electrically connected to the second node, and the drain is electrically connected to the sensing line; The first end and the second end of the capacitor are electrically connected to the first node and the second node, respectively; the anode of the organic light emitting diode is electrically connected to the second node, and the cathode is connected to the negative voltage of the power source; the switch is single-pole double Throw switch, whose moving contact is electrically connected to the sensing line, the first static contact is electrically connected to the voltage modulation module, and the second static contact is electrically connected to the sensing module;

The voltage modulation module is used to output a common voltage to the first static contact. In the rewriting phase, the voltage modulation module makes the common voltage first a second potential and switches from the second potential to a plurality of intermediate potentials in sequence. The last intermediate potential is switched to the first potential; the second potential is smaller than the first potential, the odd-numbered intermediate potentials of the plurality of intermediate potentials are larger than the first potential, the even-numbered intermediate potentials are smaller than the first potential, and the plurality of intermediate potentials are The absolute value of the difference between the first potential decreases sequentially, and the difference between the first intermediate potential and the first potential is smaller than the difference between the first potential and the second potential.