WO2016045261A1

WO2016045261A1 - Pixel circuit, driving method therefor, display panel, and display device

Info

Publication number: WO2016045261A1
Application number: PCT/CN2015/070617
Authority: WO
Inventors: 杨盛际
Original assignee: 京东方科技集团股份有限公司; 北京京东方光电科技有限公司
Priority date: 2014-09-25
Filing date: 2015-01-13
Publication date: 2016-03-31
Also published as: CN104282263A

Abstract

A pixel circuit, a driving method therefor, a display panel, and a display device. The pixel circuit comprises a power supply end (V_dd), a power supply transfer transistor (T1), a driving transistor (DTFT), a light-emitting element (OLED), a reset module, a storage capacitor (C), and a compensation module. A first end (1) of the compensation is connected to a data writing end of the pixel circuit. A second end (2) of the compensation module is connected to a gate electrode of the driving transistor (DTFT). A third end (3) of the compensation module is connected to a first terminal of the driving transistor (DTFT). A fourth end (4) of the compensation module is connected to a second terminal of the driving transistor (DTFT). A second end of the storage capacitor (C) is connected to the first terminal of the driving transistor (DTFT) via the compensation module. The compensation module is capable of outputting at the fourth end (4) of the compensation module a data voltage (V_data) inputted by the data writing end when a reset phase of the pixel circuit is finished and utilizing the data voltage (V_data) to charge the storage capacitor (C), thus compensating a threshold voltage of the driving transistor (DTFT). The display panel has uniform brightness when displaying.

Description

Pixel circuit and driving method thereof, display panel and display device

Technical field

The present invention relates to the field of organic light emitting diode display, and in particular to a pixel circuit, a method of driving the pixel circuit, a display panel including the pixel circuit, and a display device including the display panel.

Background technique

Organic light-emitting display is one of the hotspots in the research field of flat panel display. Compared with liquid crystal display, organic light-emitting diode has the advantages of low energy consumption, low production cost, self-illumination, wide viewing angle and fast response. Currently, in mobile phones, PDAs, In the display field such as digital cameras, organic light-emitting diode display panels have been replaced by conventional liquid crystal display panels. The pixel drive circuit design is the core technology content of the active matrix organic light emitting diode display panel (AMOLED), which has important research significance.

Unlike the liquid crystal panel, which uses a stable voltage to control the brightness, the organic light emitting diode is of a current driving type and requires a stable current to control the light emission.

Shown in FIG. 1 is a conventional 2T1C pixel circuit including a storage capacitor C, a driving transistor DTFT, and a switching transistor T0. When the scan line scans a row of pixels, the switching transistor T0 is turned on, and the data write signal (here, the data write signal is a voltage) is written into the storage capacitor C. At the end of the line scan, the switching transistor T0 is turned off and stored in the storage capacitor. The voltage in C drives the driving transistor DTFT to generate a current to drive the light emitting device OLED, and to ensure that the light emitting member continues to emit light within one frame. The saturation current of the driving transistor DTFT is I _OLED =K(V _GS -V _th ) ² . Wherein, I _OLED is the saturation current of the driving transistor DTFT, V _GS is the gate-source voltage of the driving transistor DTFT, and V _th is the threshold voltage of the driving transistor DTFT.

Due to the process process and device aging, etc., the threshold voltage of the driving transistor of each pixel has unevenness, which causes the current flowing through the organic light emitting diode in each pixel to change, so that the display brightness is uneven, thereby affecting the whole The display of the image.

Therefore, how to improve the brightness uniformity of the display panel has become an urgent problem in the field. Technical problem.

Summary of the invention

An object of the present invention is to provide a pixel circuit, a driving method of the pixel circuit, a display panel including the pixel circuit, and a display device including the display panel. The display panel including the pixel circuit displays uniform brightness.

In order to achieve the above object, as one aspect of the present invention, a pixel circuit includes a power supply terminal, a power conduction transistor, a driving transistor, a light emitting component, a reset module, a storage capacitor, and a compensation module.

a first end of the storage capacitor is connected to the power terminal, and a second end of the storage capacitor is connected to a gate of the driving transistor;

a first pole of the power conducting transistor is connected to the power terminal, and the power conducting transistor is capable of being turned on during a light emitting phase of the pixel circuit;

a first pole of the driving transistor is connected to a second pole of the power conducting transistor;

The reset module is coupled to a gate of the driving transistor to reset a gate voltage of the driving transistor during a reset phase of the pixel circuit;

a first end of the compensation module is connected to a data write end of the pixel circuit, a second end of the compensation module is connected to a gate of the driving transistor, and a third end of the compensation module is opposite to the driving a first pole of the transistor is connected, a fourth end of the compensation module is connected to the second pole of the driving transistor, and a second end of the storage capacitor is connected to the first pole of the driving transistor through the compensation module. The compensation module can output a data voltage input by the data write end at a fourth end of the compensation module after the reset phase of the pixel circuit ends, and charge the storage capacitor by using the data voltage To compensate for the threshold voltage of the drive transistor.

Preferably, the compensation module includes a first compensation transistor and a second compensation transistor, a first pole of the first compensation transistor is connected to a second end of the storage capacitor, and a second pole of the first compensation transistor is a first pole of the driving transistor is connected, a first pole of the second compensation transistor is connected to a data writing end of the pixel circuit, a second pole of the second compensation transistor is opposite to a second pole of the driving transistor Extreme phase The first compensation transistor can be turned on during the compensation phase, and turned off during the reset phase and the light emitting phase, and the second compensation transistor can be turned on during the compensation phase, and The reset phase and the illumination phase are turned off.

Preferably, the pixel circuit includes a first scan signal end, and a gate of the first compensation transistor and a gate of the second compensation transistor are both connected to the first scan signal end, the first compensation transistor The same type as the second compensation transistor.

Preferably, the reset module further includes a reset transistor and a reset voltage terminal, a first pole of the reset transistor is connected to the reset voltage terminal, a second pole of the reset transistor and the driving The gates of the transistors are connected, the reset transistors being able to be turned on during the reset phase of the pixel circuit and being turned off during the compensation phase and the illumination phase of the pixel circuit.

Preferably, the pixel circuit includes a second scan signal terminal, and the second scan signal terminal is connected to a gate of the reset transistor.

Preferably, the pixel circuit further includes a light-emitting member control transistor, the first pole of the light-emitting member control transistor is connected to an anode of the light-emitting member, and the light-emitting member controls a second pole of the transistor and the driving transistor The two poles are connected, and the light-emitting member control transistor can be turned off in the reset phase and the compensation phase of the pixel circuit, and turned on in the light-emitting phase of the pixel circuit.

Preferably, the pixel circuit further includes a light-emitting scanning signal terminal, a gate of the power conducting transistor and a gate of the light-emitting member control transistor are connected to the light-emitting scanning signal end, and the type of the power conducting transistor The same type as the light-emitting member control transistor.

Preferably, the power conduction transistor, the driving transistor, the first compensation transistor, and the second compensation transistor are all P-type transistors.

As another aspect of the present invention, a display panel is provided, the display panel including a pixel circuit, wherein the pixel circuit is the above-described pixel circuit provided by the present invention.

As still another aspect of the present invention, a driving method of a pixel circuit is provided, wherein the pixel circuit is the above-mentioned pixel circuit provided by the present invention, and the driving Methods include:

a resetting step: using a reset module to output a reset voltage to a gate of the driving transistor during a reset phase of the pixel circuit;

a compensation step performed after the end of the resetting step: in the compensation phase, the data write signal is valid, and the data write signal input by the data write end is used by the compensation module to charge the storage capacitor to Compensating for a threshold voltage of the driving transistor;

The illuminating step: in the illuminating phase, the illuminating control signal is effective, so that the power conducting transistor and the driving transistor are turned on to drive the illuminating member to emit light.

Preferably, the compensation module includes a first compensation transistor, a second compensation transistor, and a gate of the first compensation transistor and a first scan signal end connected to a gate of the second compensation transistor, the first compensation a first pole of the transistor is coupled to the second end of the storage capacitor, a second pole of the first compensation transistor is coupled to a first pole of the drive transistor, a first pole of the second compensation transistor is a data write end of the pixel circuit is connected, and a second electrode of the second compensation transistor is connected to the second electrode of the drive transistor,

In the compensating step, a first scan signal is input to the first scan signal terminal to control the first compensation transistor and the second compensation transistor to be turned on or off synchronously.

Preferably, the reset module includes a reset transistor and a reset voltage terminal, a first pole of the reset transistor is connected to the reset voltage terminal, a second pole of the reset transistor and the driving transistor Connected to the gate, the gate of the reset transistor is connected to the second scan signal end,

In the resetting step, a second scan signal is input to the gate of the reset transistor to control the reset transistor to be turned on during the reset phase of the pixel circuit.

Preferably, the pixel circuit further includes a light-emitting member control transistor, the first pole of the light-emitting member control transistor is connected to an anode of the light-emitting member, and the light-emitting member controls a second pole of the transistor and the driving transistor The pixel circuit further includes a light-emitting scanning signal end, and a gate of the power conducting transistor and a gate of the light-emitting component control transistor are connected to the light-emitting scanning signal end.

In the illuminating step, inputting a luminescence scan signal to the illuminating scan signal end to control the illuminant control transistor to be turned off during a reset phase and a compensation phase of the pixel circuit, and in an illuminating phase of the pixel circuit Turn on.

As still another aspect of the present invention, a display device including the above display panel provided by the present invention is provided.

In the pixel circuit provided by the present invention, the influence of the threshold voltage drift of the driving transistor on the current flowing through the illuminating member is eliminated, the brightness uniformity of the display panel including the pixel circuit can be improved, and the display panel is displayed The display defects such as afterimages are not generated, and the display effect of the display panel is optimized.

DRAWINGS

The drawings are intended to provide a further understanding of the invention, and are intended to be a In the drawing:

1 is a circuit diagram of a conventional 2T1C pixel circuit;

2 is a block diagram of a pixel circuit provided by the present invention;

3 is a schematic diagram of a pixel circuit provided by a preferred embodiment of the present invention;

4 is a timing chart of signals when driving the pixel circuit provided by the present invention;

Figure 5 is an equivalent circuit diagram of the pixel circuit shown in Figure 3 in a reset phase;

Figure 6 is an equivalent circuit diagram of the pixel circuit shown in Figure 3 in the compensation phase;

Fig. 7 is an equivalent circuit diagram of the pixel circuit shown in Fig. 3 in the light emitting phase.

Description of the reference numerals

T1: power conduction transistor T2: first compensation transistor

T3: reset transistor T4: second compensation transistor

T5: Light-emitting member control transistor C: Storage capacitor

DTFT: Drive transistor OLED: Light-emitting part

Em: illuminating scanning signal terminal Scan[1]: first scanning line

Scan[2]: second scan line V _dd : power terminal

T0: switching transistor

detailed description

The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative and not restrictive.

As shown in FIG. 2, as an aspect of the present invention, a pixel circuit is provided, which includes a power supply terminal V _dd , a power conduction transistor T1, a driving transistor DTFT, a light emitting device OLED, a storage capacitor C, and a reset module.

The first end of the storage capacitor C is connected to the power supply terminal V _dd , and the second end of the storage capacitor C is connected to the gate of the driving transistor DTFT. The first pole of the power conducting transistor T1 is connected to the power supply terminal V _dd , and the power conducting transistor T1 can be turned on during the light emitting phase of the pixel circuit (phase 3 in FIG. 4 ), and in the reset phase of the pixel circuit (Phase 1 in Figure 4) and the Compensation Phase (Phase 2 in Figure 4) are closed. The first electrode of the driving transistor DTFT is connected to the second electrode of the power conducting transistor T1.

The reset module is coupled to a gate of the drive transistor DTFT to reset a gate voltage of the drive transistor during a reset phase of the pixel circuit.

The pixel circuit further includes a compensation module, the first end 1 of the compensation module is connected to the data write end of the pixel circuit, and the second end 2 of the compensation module is connected to the gate of the drive transistor DTFT, The third end 3 of the compensation module is connected to the first pole of the driving transistor DTFT, and the fourth end 4 of the compensation module is connected to the second pole of the driving transistor DTFT. As shown in FIG. 2, the second end of the storage capacitor C is connected to the second end 2 of the compensation module, and the second end of the storage capacitor C is connected to the second pole of the driving transistor DTFT through the compensation module, so that The compensation module is capable of outputting the data voltage V _data input by the data write end at the fourth end of the compensation module after the reset phase of the pixel circuit ends, and using the data voltage V _data to the storage capacitor C is charged to compensate for the threshold voltage of the driving transistor DTFT.

It will be understood by those skilled in the art that the source and drain of the driving transistor DTFT are not fixed. The first pole of the driving transistor DTFT may be the source of the driving transistor DTFT or the drain of the driving transistor DTFT. Correspondingly, the second electrode of the driving transistor DTFT may be the drain of the driving transistor DTFT or the source of the driving transistor DTFT. In the energized state, one of the first and second poles of the driving transistor DTFT is connected to the source of the driving transistor DTFT, and one of the low level is the drain of the driving transistor DTFT.

Specifically, if the first pole of the driving transistor DTFT is connected to the high level and the second pole of the driving transistor DTFT is connected to the low level, the source of the first extreme driving transistor DTFT of the driving transistor DTFT, the driving transistor DTFT The second electrode is the drain of the driving transistor DTFT. On the contrary, if the first pole of the driving transistor DTFT is connected to the low level and the second pole of the driving transistor DTFT is connected to the high level, the drain of the first driving transistor DTFT of the driving transistor DTFT, the driving transistor DTFT The second is the source of the drive transistor DTFT.

In the present invention, the first pole and the other of the other transistors (including the power conducting transistor T1 above and the first compensating transistor T2, the second compensating transistor T4, the reset transistor T3, and the illuminant controlling transistor T5 to be described later) The meaning of the two poles is similar to the meaning of the first and second poles of the drive transistor.

It is easily understood that in the reset phase, the gate voltage signal of the driving transistor DTFT is reset, and the level of the gate of the driving transistor DTFT is set to the turn-on level of the driving transistor DTFT. Here, the turn-on level means that the driving transistor DTFT can be turned on in a case where one of the first pole and the second pole of the driving transistor DTFT is connected to the high level and the other is connected to the low level. Level.

After the reset phase is over, the pixel circuit enters a compensation phase in which the data voltage is written to the pixel circuit through the compensation module. At this stage, the fourth end of the compensation module outputs a data voltage _Vdata , that is, the data write end maintains the potential of the second pole of the driving transistor DTFT at V _data through the fourth end of the compensation module. The first electrode of the driving transistor DTFT is connected to the second end of the storage capacitor C to charge the storage capacitor. Since the gate of the driving transistor DTFT is connected to the second end of the storage capacitor C, the data input terminal charges the storage capacitor C while charging the gate of the driving transistor DTFT, when the driving transistor DTFT is When the potential of the gate is pulled up to V _data -V _th , the potential difference between the gate and the second pole of the driving transistor DTFT is V _th , that is, the gate-source voltage V _GS of the driving transistor DTFT is V _th . In the critical state of the driving transistor, when the charging is continued, the gate potential of the driving transistor DTFT is slightly increased, the driving transistor DTFT is turned off, the charging is completed, and the storage capacitor C maintains the gate voltage of the driving transistor DTFT at V. _Data -V _th .

After the compensation phase of the pixel circuit ends, the pixel circuit enters a light-emitting phase, the power conduction transistor T1 is turned on, and the driving transistor DTFT is turned on to form a current through the light-emitting element OLED. At this time, the gate voltage of the driving transistor DTFT is V _data -V _th , and the first terminal voltage of the driving transistor DTFT is V _dd . Therefore, in the light emitting phase, the gate-source voltage of the driving transistor DTFT is V _GS =V _dd -(V _Data -V _th ).

The current through the OLED OLED is calculated by the following formula (1):

I _OLED = K(V _GS -V _th ) ² (1)

=K[V _dd -(V _data -V _th )-V _th ] ²

=K(V _dd -V _data ) ²

Where V _GS is the gate-source voltage of the driving transistor DTFT, and V _th is the threshold voltage of the driving transistor DTFT.

Only from the above equation, to the light emitting element OLED and the magnitude of the current supplied from the terminal power supply voltage V _dd and an input terminal of the data voltage V _data is related not affected by the threshold voltage V _th of the driving transistor DTFT.

From this, it can be seen that even if the threshold voltage of the driving transistor DTFT drifts, the current flowing through the light-emitting element OLED does not change. That is, in the pixel circuit provided by the present invention, the influence of the threshold voltage drift of the driving transistor DTFT on the current flowing through the light emitting element OLED is eliminated, so that the brightness uniformity of the display panel including the pixel circuit can be improved, and The display panel does not generate display defects such as afterimages during display, thereby optimizing the display effect of the display panel.

As a preferred embodiment of the present invention, as shown in FIG. 3, the compensation module may include a first compensation transistor T2 and a second compensation transistor T4, and a first pole of the first compensation transistor T2 (corresponding to the compensation module) The second end is connected to the second end of the storage capacitor C. The second pole of the first compensation transistor T2 (corresponding to the third end of the compensation module) is connected to the first pole of the driving transistor DTFT, and the second compensation crystal a first pole of the body tube T4 (corresponding to the first end of the compensation module) is connected to the data write end of the pixel circuit, and a second pole of the second compensation transistor T4 (corresponding to the fourth of the compensation module) The terminal is connected to the second electrode of the driving transistor DTFT, the first compensation transistor T2 can be turned on during the compensation phase of the pixel circuit, and is turned off during the reset phase and the light emitting phase, and the second compensation transistor T4 can It is turned on during the compensation phase and is turned off during the reset phase and the lighting phase.

Specifically, in the compensation phase, the first compensation transistor T2 and the second compensation transistor T4 are turned on. At this time, the potential of the second electrode of the driving transistor DTFT is always V _data , and the data input terminal charges the driving transistor DTFT when When the potential of the gate of the driving transistor DTFT is pulled up to V _data -V _th , the potential difference between the gate and the second electrode of the driving transistor DTFT is V _th , and after the charging is completed, the storage capacitor C will be the gate of the driving transistor DTFT. The pole voltage is maintained at V _data -V _th .

In the present invention, a control terminal may be provided at the gate of the first compensation transistor T2 and the gate of the second compensation transistor T4, respectively, to pass to the gate of the first compensation transistor T2 and the gate of the second compensation transistor T4, respectively. A control signal is provided to enable the first compensation transistor T2 and the second compensation transistor T4 to be turned off during the reset phase and the light-emitting phase, and turned on during the compensation phase.

As can be seen from the above description, the opening and closing of the first compensation transistor T2 and the second compensation transistor T4 are synchronized. In order to simplify the structure of the pixel circuit, preferably, the pixel circuit includes a first scan signal end, the A gate of a compensation transistor and a gate of the second compensation transistor are both connected to the first scan signal terminal. In this embodiment, the first compensation transistor T2 and the second compensation transistor T4 are of the same type. That is, the first compensation transistor T2 and the second compensation transistor T4 are both N-type transistors or the same P-type transistors.

In order to achieve a reset level to the driving transistor DTFT during the reset phase, preferably, the pixel circuit further includes a reset transistor T3 and a reset voltage terminal V _com , the first pole of the reset transistor T3 and a reset The voltage terminal V _{com is} connected, the second electrode of the reset transistor T3 is connected to the gate of the driving transistor DTFT, the reset transistor T3 can be turned on during the reset phase of the pixel circuit, and can be in the compensation phase of the pixel circuit And the lighting phase is off.

In order to realize that the reset transistor T3 can be turned on during the reset phase of the pixel circuit and can be turned off in the compensation phase and the light emitting phase of the pixel circuit, preferably, the pixel circuit can include a second scan signal terminal, The second scan signal terminal is connected to the gate of the reset transistor T3.

As a preferred embodiment of the present invention, as shown in FIG. 3, the pixel circuit may further include a light-emitting member control transistor T5, and the first pole of the light-emitting member control transistor T5 is connected to the anode of the light-emitting member OLED, and the light-emitting member The second electrode of the control transistor T5 is connected to the second electrode of the driving transistor DTFT, and the light-emitting member control transistor T5 can be turned off during the reset phase and the compensation phase of the pixel circuit, and turned on during the light-emitting phase of the pixel circuit.

Since the light-emitting member control transistor T5 is turned off in the reset phase and the compensation phase of the pixel circuit, it is possible to prevent current from passing through the light-emitting member OLED in the reset phase and the compensation phase, thereby extending the life of the light-emitting member OLED.

As described above, the power conducting transistor T1 is turned on during the light emitting phase of the pixel circuit, and is turned off during both the reset phase and the compensation phase of the pixel circuit. It can be seen that the turn-on and turn-off timing of the power conducting transistor T1 is synchronized with the turn-on and turn-off timing of the light-emitting member control transistor T5.

In the present invention, in order to realize the synchronous control of the power conducting transistor T1 and the light emitting device controlling transistor T5 with a simple structure, preferably, the pixel circuit may further include a light emitting scanning signal terminal, a gate of the power conducting transistor T1, and a light emitting member. The gate of the control transistor T5 is connected to the light-emitting scanning signal terminal. In this embodiment, the power conducting transistor T1 and the light-emitting member controlling transistor T5 are of the same type. That is, the power conduction transistor T1 and the light-emitting member control transistor T5 may be the same as the N-type transistor or the same as the P-type transistor.

In the present invention, the specific form of each transistor is not particularly limited. For example, as one embodiment of the present invention, the power conduction transistor T1, the driving transistor DTFT, the first compensation transistor T2, and the second compensation transistor T4 may each be a P-type transistor, further, a reset transistor T3 and a light-emitting member control transistor. T5 is also a P-type transistor.

As another aspect of the present invention, the above pixel power provided by the present invention is provided The driving method of the road, the driving method includes:

a resetting step: in the reset phase of the pixel circuit (stage 1 in FIG. 4), using the reset module to output a reset voltage to a gate of the driving transistor;

a compensation step performed after the end of the resetting step: in the compensation phase (phase 2 in FIG. 4), the data write signal and the scan signal are valid, and the data input to the data write end is written by the compensation module The input signal charges the storage capacitor to compensate for a threshold voltage of the driving transistor;

Light-emitting step: In the light-emitting phase (stage 3 in FIG. 4), the light-emission control signal is active, and the power-conducting transistor and the drive transistor are turned on to drive the light-emitting member to emit light.

In driving the pixel circuit provided by the present invention, the influence of the threshold voltage drift of the driving transistor DTFT on the current flowing through the OLED OLED is eliminated, so that the display panel does not generate display defects such as afterimages during display, and is optimized. Display panel display effect.

In the compensating step, the storage capacitor is charged by the data write signal to compensate the threshold voltage of the driving transistor, and no other compensation signal needs to be introduced. Therefore, the pixel driving method provided by the present invention is relatively simple.

As described above, in order to simplify the structure of the pixel circuit, the pixel circuit includes a first scan signal end, and the gate of the first compensation transistor T2 and the gate of the second compensation transistor T4 are both connected to the first scan signal end. The first compensation transistor T2 and the second compensation transistor T4 are of the same type. Correspondingly, the display panel including the pixel circuit includes a first scan line Scan[1], and the first scan line Scan[1] is connected to the first scan signal end to input to the first scan signal end The first scan signal.

Therefore, the driving method includes: in the compensating step, providing a first scan signal to the first scan signal terminal through the first scan line Scan[1] to control the synchronization of the first compensation transistor T2 and the second compensation transistor T4. Ground is turned on or off. As an embodiment of the present invention, the first compensation transistor T2 and the second compensation transistor T4 are both P-type transistors. Therefore, as shown in FIG. 4, the first scan line Scan[1] can be in the reset phase and emit light. The stage outputs a high level signal, and controls the first compensation transistor T2 and the second compensation transistor T4 to be turned off, and the first scan line Scan[1] can be compensated The phase outputs a low level signal, and controls the first compensation transistor T2 and the second compensation transistor T4 to be turned on.

As described above, in order to facilitate control of the pixel circuit for resetting, preferably, the reset module may include a reset transistor T3 and a reset voltage terminal, resetting the first pole of the transistor T3 and the reset voltage Connected to the terminal, the second electrode of the reset transistor T3 is connected to the gate of the driving transistor DTFT, and the gate of the reset transistor T3 is connected to the second scanning signal terminal. Correspondingly, the driving method includes: in the resetting step, inputting a second scan signal to a gate of the reset transistor T3, controlling the reset transistor T3 to be turned on during a reset phase of the pixel circuit, and controlling The reset transistor T3 is turned off during the compensation phase and the light emitting phase of the pixel circuit.

In order to achieve resetting of the pixel circuit, the pixel circuit includes a second scan signal end, and the second scan signal end is connected to the gate of the reset transistor T3. Accordingly, the display panel including the pixel circuit further includes The second scan line Scan[2] is connected to the second scan signal end to provide a second scan signal for the second scan signal end. Therefore, the driving method includes: in the resetting step, inputting a second scan signal to the reset voltage terminal to control the reset transistor to be turned on during a reset phase of the pixel circuit.

A signal is supplied to the second scan signal terminal through the second scan line Scan[2] to control the turn-on and turn-off of the reset transistor T3. In the embodiment provided by the present invention, the reset transistor T3 may be a P-type transistor, and therefore, the second scan line Scan[2] provides a low level for turning on the reset transistor T3 during the reset phase, in the compensation phase. The illuminating phase provides a high level that turns off reset transistor T3.

As a preferred embodiment of the present invention, the pixel circuit further includes a light-emitting member control transistor T5. The first pole of the light-emitting member control transistor T5 is connected to the anode of the light-emitting member OLED, and the light-emitting member controls the second pole of the transistor T5. The second electrode of the driving transistor DTFT is connected, and the light-emitting member control transistor T5 can be turned off in the reset phase and the compensation phase of the pixel circuit, and turned off in the light-emitting phase of the pixel circuit.

Correspondingly, the driving method may include: inputting, in the light emitting step, a light emitting scan signal to the light emitting scanning signal end to control the light emitting part to control the crystal The body tube is turned off during the reset phase and the compensation phase of the pixel circuit, and is turned on during the light emitting phase of the pixel circuit.

In order to simplify the structure of the pixel circuit, preferably, the pixel circuit further includes a light-emitting scanning signal terminal, and a gate of the power-conducting transistor T1 and a gate of the light-emitting member control transistor T5 are connected to the light-emitting scanning signal end. In the case, the power conduction transistor T1 is of the same type as the light-emitting member control transistor T5. Correspondingly, each of the scan lines further includes a light-emitting scan signal line Em, and the light-emitting scan signal line Em is connected to the light-emitting scan signal end. The illuminating scan signal is output to the illuminating scanning signal terminal through the illuminating scanning line Em, and the turning on and off of the power conducting transistor T1 and the illuminating device controlling transistor T5 are controlled.

In the embodiment of the present invention, the power conduction transistor T1 and the illuminant control transistor T5 are both P-type transistors. Therefore, the illuminating scan line Em outputs a low level signal in the reset phase and the compensation phase, and outputs a high level in the illuminating phase. signal.

As described above, the power conduction transistor T1, the driving transistor DTFT, the first compensation transistor T2, and the second compensation transistor T4 may each be a P-type transistor. Further, the reset transistor T3 and the light-emitting member control transistor T5 are also P-type transistors.

A method of driving a display substrate including a pixel circuit of a preferred embodiment provided by the present invention will be described below with reference to FIGS. 3 through 7.

The pixel circuit shown in FIG. 3 is a 5T1C pixel circuit in which only five transistors and one capacitor are used, and therefore, the aperture ratio of the pixel circuit can be effectively improved. Also, in the pixel circuit shown in FIG. 3, the transistors used are all P-type transistors that are turned on at a low level. The arrows in Figs. 5 to 7 indicate the flow direction of the current, and the portion indicated by the broken line is the portion through which no current flows.

Reset step: in the reset phase shown in FIG. 5, the second scan line Scan[2] outputs a low level signal to the second control terminal to control the reset transistor T3 to be turned on, thereby driving the transistor DTFT The gate writes a reset voltage V _com . At this stage, the first scan line Scan[1] and the light-emission scanning signal line Em each output a high level, and therefore, the power supply conducting transistor T1, the light-emission control transistor T5, the first compensation transistor T2, and the second compensation transistor T4 are all turned off.

Compensation step: in the compensation phase shown in FIG. 6, the data line is written to the data signal _Vdata , and the first scan line Scan[1] outputs a low level signal to control the first compensation transistor T2 and the second compensation transistor T4 to be turned on. Since the gate of the driving transistor DTFT is the reset voltage V _com written in the reset phase, the driving transistor DTFT is also turned on at this time, and at this time, the gate voltage of the driving transistor DTFT can be changed to V _data -V _th . At this stage, both the second scan line Scan[2] and the light-emission scanning signal line Em output a high level, and therefore, the power supply conducting transistor T1, the light-emission control transistor T5, and the reset transistor T3 are both turned off.

Light-emitting step: In the light-emitting phase shown in FIG. 7, the light-emitting scanning signal line Em outputs a low level, causing the power-conducting transistor T1 and the light-emission control transistor T5 to be turned on, and thus, the light-emitting element OLED can emit light. At this time, the first scan line Scan[1] and the second scan line Scan[2] both output a high level, and therefore, the first compensation transistor T2, the second compensation transistor T4, and the reset transistor T3 are both turned off. As described above, the current IOLED flowing through the OLED OLED can be calculated by the following formula:

I _OLED = K(V _GS -V _th ) ²

=K[V _dd -(V _data -V _th )-V _th ] ²

=K(V _dd -V _data ) ²

From the above equation, only the magnitude of the current flowing through the light emitting element OLED and the power supply terminal voltage V _dd supplied input terminal and a data voltage V _data is related not affected by the threshold voltage V _th of the driving transistor DTFT.

As still another aspect of the present invention, a display panel is provided, the display panel including a pixel circuit, wherein the pixel circuit is the above-described pixel circuit provided by the present invention.

The display panel has uniform illumination brightness, and there is no display defect such as afterimage, and a high quality image can be displayed.

As still another aspect of the present invention, a display device including the above display panel provided by the present invention is provided. The display device of the present invention may be in a television, a computer display, a mobile phone or the like.

It is to be understood that the above embodiments are merely exemplary embodiments employed to explain the principles of the invention, but the invention is not limited thereto. For those of ordinary skill in the art, without departing from the spirit and scope of the present invention Various modifications and improvements can be made, and such modifications and improvements are also considered to be within the scope of the invention.

Claims

A pixel circuit, comprising: a power supply terminal, a power conduction transistor, a driving transistor, a light emitting component, a reset module, a storage capacitor, and a compensation module,

a first end of the storage capacitor is connected to the power terminal, and a second end of the storage capacitor is connected to a gate of the driving transistor;

a first pole of the power conducting transistor is connected to the power terminal, and the power conducting transistor is capable of being turned on during a light emitting phase of the pixel circuit;

a first pole of the driving transistor is connected to a second pole of the power conducting transistor;

The reset module is coupled to a gate of the driving transistor to reset a gate voltage of the driving transistor during a reset phase of the pixel circuit;

a first end of the compensation module is connected to a data write end of the pixel circuit, a second end of the compensation module is connected to a gate of the driving transistor, and a third end of the compensation module is opposite to the driving a first pole of the transistor is connected, a fourth end of the compensation module is connected to the second pole of the driving transistor, and a second end of the storage capacitor is connected to the first pole of the driving transistor through the compensation module. The compensation module can output a data voltage input by the data write end at a fourth end of the compensation module after the reset phase of the pixel circuit ends, and charge the storage capacitor by using the data voltage To compensate for the threshold voltage of the drive transistor.
The pixel circuit of claim 1 , wherein the compensation module comprises a first compensation transistor and a second compensation transistor, a first pole of the first compensation transistor is connected to a second end of the storage capacitor, a second pole of the first compensation transistor is connected to a first pole of the driving transistor, a first pole of the second compensation transistor is connected to a data writing end of the pixel circuit, and the second compensation transistor is a second pole is coupled to the second pole of the drive transistor, the first compensation transistor is turnable during the compensation phase, and is turned off during the reset phase and the light emitting phase, and the second compensation transistor Can be turned on during the compensation phase, and The reset phase and the illumination phase are turned off.
The pixel circuit according to claim 2, wherein the pixel circuit comprises a first scan signal end, a gate of the first compensation transistor and a gate of the second compensation transistor are both the first The scan signal terminals are connected, and the first compensation transistor and the second compensation transistor are of the same type.
The pixel circuit according to any one of claims 1 to 3, wherein the reset module includes a reset transistor and a reset voltage terminal, a first pole of the reset transistor and the reset voltage Connected to the end, the second pole of the reset transistor is connected to the gate of the driving transistor, the reset transistor can be turned on during the reset phase of the pixel circuit, and in the compensation phase of the pixel circuit and The lighting phase is off.
The pixel circuit according to claim 4, wherein said pixel circuit comprises a second scan signal terminal, and said second scan signal terminal is connected to a gate of said reset transistor.
The pixel circuit according to any one of claims 1 to 3, wherein the pixel circuit further comprises a light-emitting member control transistor, and the first electrode of the light-emitting member control transistor is connected to an anode of the light-emitting member, a second pole of the light-emitting member control transistor is connected to a second pole of the driving transistor, the light-emitting member control transistor being capable of being turned off during a reset phase and a compensation phase of the pixel circuit, and emitting light in the pixel circuit The stage is turned on.
The pixel circuit according to claim 6, wherein the pixel circuit further comprises a light-emitting scanning signal end, a gate of the power conducting transistor and a gate of the light-emitting member control transistor are both coupled to the light-emitting scanning signal The terminals are connected, and the type of the power conduction transistor is the same as the type of the light-emitting member control transistor.
The pixel circuit according to claim 2 or 3, wherein the power conduction transistor, the drive transistor, the first compensation transistor, and the second compensation transistor are all P-type transistors.
A display panel comprising a pixel circuit, wherein the pixel circuit is the pixel circuit according to any one of claims 1 to 8.
A driving method of a pixel circuit, wherein the pixel circuit is the pixel circuit of claim 1, the driving method comprising:

a resetting step: using a reset module to output a reset voltage to a gate of the driving transistor during a reset phase of the pixel circuit;

a compensation step performed after the end of the resetting step: in the compensation phase, the data write signal is valid, and the storage capacitor is charged by the compensation module by using a data write signal input by the data write end to Compensating for a threshold voltage of the driving transistor;

The illuminating step: in the illuminating phase, the illuminating control signal is effective, so that the power conducting transistor and the driving transistor are turned on to drive the illuminating member to emit light.
The driving method according to claim 10, wherein the compensation module comprises a first compensation transistor, a second compensation transistor, and a gate of the first compensation transistor and a gate of the second compensation transistor a first scan signal terminal, a first pole of the first compensation transistor is connected to a second end of the storage capacitor, and a second pole of the first compensation transistor is connected to a first pole of the driving transistor, a first pole of the second compensation transistor is connected to a data write end of the pixel circuit, and a second pole of the second compensation transistor is connected to a second pole of the drive transistor,

In the compensating step, a first scan signal is input to the first scan signal terminal to control the first compensation transistor and the second compensation transistor to be turned on or off synchronously.
The driving method according to claim 10 or 11, wherein the reset module comprises a reset transistor and a reset voltage terminal, and a first pole of the reset transistor is connected to the reset voltage terminal a second pole of the reset transistor is connected to a gate of the driving transistor, and a gate of the reset transistor is connected to a second scan signal end,

In the resetting step, a second scan signal is input to the gate of the reset transistor to control the reset transistor to be turned on during the reset phase of the pixel circuit.
The driving method according to claim 10 or 11, wherein the pixel circuit further comprises a light-emitting member control transistor, wherein the first pole of the light-emitting member control transistor is connected to an anode of the light-emitting member, the light-emitting member a second pole of the control transistor is connected to the second pole of the driving transistor, the pixel circuit further includes a light emitting scanning signal end, a gate of the power conducting transistor and a gate of the light emitting control transistor are both The illuminating scanning signal ends are connected,

In the illuminating step, inputting a luminescence scan signal to the illuminating scan signal end to control the illuminant control transistor to be turned off in a reset phase and a compensation phase of the pixel circuit, and in an illuminating phase of the pixel circuit Turn on.
A display device comprising a display panel, wherein the display panel is the display panel of claim 9.