WO2021232741A1

WO2021232741A1 - Pixel drive circuit and oled display panel

Info

Publication number: WO2021232741A1
Application number: PCT/CN2020/132790
Authority: WO
Inventors: 杨波; 梁鹏飞
Original assignee: 深圳市华星光电半导体显示技术有限公司
Priority date: 2020-05-19
Filing date: 2020-11-30
Publication date: 2021-11-25
Also published as: CN111583862B; CN111583862A

Abstract

Provided are a pixel drive circuit and an OLED display panel; the anodes of all of the light-emitting devices (202) in the pixel drive circuit are connected together; the cathodes are connected to the output terminals of drive modules (203); in a light-emitting phase (t2), the current values of the output terminals of the drive modules (203) in the pixel drive circuits corresponding to different pixels all are within a preset range; therefore the current flowing through the cathodes of the light-emitting devices (202) located at different positions of the OLED display panel is less affected by the voltage drop of the power supply, and thus the brightness of the OLED display panel is uniform.

Description

Pixel drive circuit and OLED display panel

Technical field

This application relates to the field of display technology, and in particular to a pixel driving circuit and an OLED display panel.

Background technique

As shown in Figure 1, it is an existing 3T1C pixel drive circuit, including a data signal input module 101, a light emitting device 102, a drive module 103, a detection module 104, and a storage module 105. The data signal input module 101 is used for data In the writing stage, under the control of the first control signal WR, the data signal is input to the first point g, the cathode of the light-emitting device 102 is connected to the second power signal VSS, and the first input terminal of the driving module 103 is connected to the first point g through the first point g. The data signal input module 101 is connected, the second input terminal of the driving module 103 is connected to the anode of the light-emitting device 102 through the second point s, the output terminal of the driving module 103 is connected to the second power signal VDD, and the driving module 103 is used for the first Under the potential control of point g, the light emitting device 102 is driven to emit light, and the detection module 104 is connected to the driving module 103 through the second point s for detecting the driving module 103 under the control of the third control signal RD in the detection phase The storage module 105 is connected to the driving module 103 through the first point g and the second point s, and is used to store the threshold voltage of the driving module 103.

Specifically, the data signal input module 101 includes a first transistor T10, the light emitting device 102 is an organic light emitting diode OLED, the driving module 103 includes a second transistor T20, and the detection module 104 includes a third transistor T30, a sense-line, and a single pole. For the double throw switch K, the storage module 105 includes a storage capacitor Cst, wherein the gate of the first transistor T10 is connected to the first control signal WR, the first electrode is connected to the data line DATA, the second electrode is connected to the first point g, and the second transistor T20 The gate of the transistor T30 is connected to the first point g, the first electrode is connected to the first power signal VDD, the second electrode is connected to the anode of the light emitting device 105, the gate of the third transistor T30 is connected to the third control signal RD, and the first electrode is connected to the second point s, the second electrode is connected to the first end of the sensing line Sense-line, the moving contact T of the SPDT switch K is connected to the second end of the sensing line Sense-line, the first static contact of the SPDT switch K S1 is connected to the reference voltage VREF, the second stationary contact S2 is connected to the analog-to-digital converter ADC, the first plate of the storage capacitor Cst is connected to the first point g, and the second plate is connected to the second point s.

It can be seen from FIG. 1 that in the existing pixel driving circuit, the cathode of the OLED of the entire panel is connected to the second power signal VSS. However, the cathodes at different positions on the panel have different resistances to the collection point. The farther away from the input terminal, the greater the resistance. The difference in resistance will cause the voltage of the cathode farther from the input terminal to be lower than that of the closer to the input terminal. The voltage of the cathode at the position of the cathode produces a power supply voltage drop (IR-Drop) phenomenon, so that the current flowing through the OLED is different. The farther away from the input terminal, the smaller the current. This difference in current will eventually lead to the brightness of the display screen. Evenly.

Therefore, the existing OLED display panel has a technical problem of uneven brightness of the screen, which needs to be improved.

technical problem

The embodiments of the present application provide a pixel driving circuit and an OLED display panel to alleviate the technical problem of uneven brightness of the screen in the existing OLED display panel.

Technical solutions

In order to solve the above problems, the technical solutions provided by this application are as follows:

An embodiment of the present application provides a pixel driving circuit, including:

The data signal input module is used to input a data signal to the first point under the control of the first control signal during the data writing stage;

A light emitting device, the anode of the light emitting device is connected to the first power signal;

Drive module, the first input end of the drive module is connected to the data signal input module through the first point, the second input end of the drive module is connected to a second power signal, and the output end of the drive module Connected with the cathode of the light-emitting device, the driving module is configured to drive the light-emitting device to emit light under the control of a second control signal and the potential of the first point;

The detection module is connected to the drive module through the second point, and is used to detect the threshold voltage of the drive module under the control of a third control signal in the detection phase;

A storage module, connected to the driving module through the first point and the second point, and used to store the threshold voltage of the driving module;

In the light-emitting phase, in the pixel drive circuits corresponding to different pixels, the current values of the output terminals of the drive modules are all within a preset range.

In the pixel driving circuit of the present application, the data signal input module includes a first transistor, the gate of the first transistor is connected to the first control signal, and the first electrode of the first transistor is connected to the data line , The second electrode of the first transistor is connected to the first point.

In the pixel driving circuit of the present application, the light-emitting device is an organic light-emitting diode.

In the pixel driving circuit of the present application, the driving module includes a second transistor and a third transistor, the gate of the second transistor is connected to the first point, and the first electrode of the second transistor is connected to the The second point is connected, the second electrode of the second transistor is connected to the cathode of the light emitting device, the gate of the third transistor is connected to the second control signal, and the first electrode of the third transistor is connected to The second power signal is connected, and the second electrode of the third transistor is connected to the second point.

In the pixel driving circuit of the present application, in the data writing phase and the light emitting phase, the second control signal is at a high potential.

In the pixel driving circuit of the present application, in the detection phase, the second control signal is at a low level.

In the pixel driving circuit of the present application, the detection module includes a fourth transistor, a sensing line, and a single-pole double-throw switch, the gate of the fourth transistor is connected to the third control signal, and the fourth transistor The first electrode is connected to the second point, the second electrode of the fourth transistor is connected to the first end of the sensing line, and the moving contact of the SPDT switch is connected to the second end of the sensing line , The first static contact of the single-pole double-throw switch is connected to a reference voltage, and the second static contact of the single-pole double-throw switch is connected to an analog-to-digital converter.

In the pixel driving circuit of the present application, the detection module is used to control the moving contact of the single-pole double-throw switch to connect with the first static contact during the initialization phase of the detection phase, and In the voltage detection phase of the measurement phase, the movable contact of the single-pole double-throw switch is controlled to be connected with the second static contact.

In the pixel driving circuit of the present application, the storage module includes a storage capacitor, a first plate of the storage capacitor is connected to the first point, and a second plate of the storage capacitor is connected to the second point .

In the pixel drive circuit of the present application, the pixel drive circuit further includes a switch module connected to the cathode of the light-emitting device, and the switch module is used to control the fourth control signal during the detection phase. Next, cut off the connection between the light-emitting device and the drive module.

In the pixel driving circuit of the present application, the switch module includes a fifth transistor, the gate of the fifth transistor is connected to the fourth control signal, and the first electrode of the fifth transistor is connected to the light emitting device. The cathode is connected, and the second electrode of the fifth transistor is connected to the first power signal.

In the pixel driving circuit of the present application, in the data writing phase and the light emitting phase, the fourth control signal is at a low potential.

In the pixel driving circuit of the present application, in the detection phase, the fourth control signal is at a high level.

In the pixel driving circuit of the present application, the first control signal, the second control signal, the third control signal, and the fourth control signal are all provided by an external timing device.

The present application also provides an OLED display panel, including a plurality of pixels and a pixel driving circuit for driving the pixels, the pixel driving circuit includes:

In the OLED display panel of the present application, the data signal input module includes a first transistor, the gate of the first transistor is connected to the first control signal, and the first electrode of the first transistor is connected to the data line , The second electrode of the first transistor is connected to the first point.

In the OLED display panel of the present application, the light-emitting device is an organic light-emitting diode.

In the OLED display panel of the present application, the driving module includes a second transistor and a third transistor, the gate of the second transistor is connected to the first point, and the first electrode of the second transistor is connected to the The second point is connected, the second electrode of the second transistor is connected to the cathode of the light emitting device, the gate of the third transistor is connected to the second control signal, and the first electrode of the third transistor is connected to The second power signal is connected, and the second electrode of the third transistor is connected to the second point.

In the OLED display panel of the present application, the detection module includes a fourth transistor, a sensing line, and a single-pole double-throw switch, the gate of the fourth transistor is connected to the third control signal, and the fourth transistor The first electrode is connected to the second point, the second electrode of the fourth transistor is connected to the first end of the sensing line, and the moving contact of the SPDT switch is connected to the second end of the sensing line , The first static contact of the single-pole double-throw switch is connected to a reference voltage, and the second static contact of the single-pole double-throw switch is connected to an analog-to-digital converter.

In the OLED display panel of the present application, the storage module includes a storage capacitor, a first plate of the storage capacitor is connected to the first point, and a second plate of the storage capacitor is connected to the second point .

Beneficial effect

Beneficial effects of this application: this application provides a pixel drive circuit and an OLED display panel. The pixel drive circuit includes a data signal input module, a light emitting device, a drive module, a detection module, and a storage module; the data signal input module is used to write data In the entry stage, under the control of the first control signal, a data signal is input to the first point; the anode of the light-emitting device is connected to the first power signal; the first input terminal of the driving module is connected to the data signal input module through the first point , The second input terminal of the driving module is connected with the second power signal, the output terminal of the driving module is connected with the cathode of the light-emitting device, and the driving module is used for driving the light-emitting device to emit light under the control of the second control signal and the potential of the first point; The detection module is connected to the drive module through the second point for detecting the threshold voltage of the drive module under the control of the third control signal in the detection phase; the storage module is connected to the drive module through the first point and the second point , Is used to store the threshold voltage of the driving module; wherein, in the pixel driving circuit corresponding to different pixels, the current value of the output terminal of the driving module is in the preset range during the light-emitting phase. In the pixel driving circuit of the present application, the anodes of all light-emitting devices are connected together, and the cathodes are connected to the output terminal of the driving module. In the light-emitting phase, in the pixel driving circuit corresponding to different pixels, the current value of the output terminal of the driving module is all In the preset range, the current flowing through the cathodes of the light-emitting devices located at different positions of the OLED display panel is less affected by the voltage drop of the power supply, so that the display brightness of the OLED display panel is uniform.

Description of the drawings

In order to explain the embodiments or the technical solutions in the prior art more clearly, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only for application. For some embodiments, those of ordinary skill in the art can obtain other drawings based on these drawings without creative work.

FIG. 1 is a schematic diagram of the structure of a pixel driving circuit in the prior art.

FIG. 2 is a schematic diagram of a first structure of a pixel driving circuit provided by an embodiment of the application.

FIG. 3 is a first timing diagram of various signals of the pixel driving circuit provided in an embodiment of the application during the display phase.

FIG. 4 is a schematic diagram of the first type of switching of each transistor in the display stage of the pixel driving circuit provided by an embodiment of the application.

FIG. 5 is a first timing diagram of each signal in the detection phase of the pixel driving circuit provided by an embodiment of the application.

6 is a schematic diagram of the first switching of each transistor in the detection phase of the pixel driving circuit provided by the embodiment of the application.

FIG. 7 is a schematic diagram of a first structure of a pixel driving circuit provided by an embodiment of the application.

FIG. 8 is a second timing diagram of various signals of the pixel driving circuit in the display phase according to an embodiment of the application.

FIG. 9 is a schematic diagram of the second type of switching of each transistor in the display phase of the pixel driving circuit provided by an embodiment of the application.

FIG. 10 is a second timing diagram of various signals in the detection phase of the pixel driving circuit provided by an embodiment of the application.

FIG. 11 is a schematic diagram of the second type of switching of each transistor in the detection phase of the pixel driving circuit according to an embodiment of the application.

Embodiments of the present invention

The description of the following embodiments refers to the attached drawings to illustrate specific embodiments that can be implemented in the present application. The directional terms mentioned in this application, such as [Up], [Down], [Front], [Back], [Left], [Right], [Inner], [Outer], [Side], etc., are for reference only The direction of the additional schema. Therefore, the directional terms used are used to illustrate and understand the application, rather than to limit the application. In the figure, the units with similar structures are indicated by the same reference numerals.

As shown in FIG. 2, it is a schematic diagram of the first structure of the pixel driving circuit provided in this application. The pixel drive circuit includes a data signal input module 201, a light emitting device 202, a drive module 203, a detection module 204, and a storage module 205;

The data signal input module 201 is used to input a data signal to the first point g under the control of the first control signal WR during the data writing stage;

The anode of the light emitting device 202 is connected to the first power signal VDD;

The first input terminal of the driving module 203 is connected to the data signal input module 201 through the first point g, the second input terminal of the driving module 203 is connected to the second power signal VSS, and the output terminal of the driving module 203 is connected to the cathode of the light emitting device 202 , The driving module 203 is configured to drive the light-emitting device 202 to emit light under the control of the second control signal EM and the potential of the first point g;

The detection module 204 is connected to the driving module 203 through the second point s, and is used for detecting the threshold voltage of the driving module 203 under the control of the third control signal RD in the detection phase;

The storage module 205 is connected to the driving module 203 through the first point g and the second point s, and is used to store the threshold voltage of the driving module 203;

In the light-emitting phase, in the pixel driving circuits corresponding to different pixels, the current values of the output terminals of the driving module 203 are all within a preset range.

Specifically, the data signal input module 201 includes a first transistor T1, the gate of the first transistor T1 is connected to the first control signal WR, the first electrode of the first crystal T1 is connected to the data line DATA, and the second transistor T1 is connected to the data line DATA. The electrode is connected to the first point g.

The light emitting device 202 is an organic light emitting diode OLED.

The driving module 203 includes a second transistor T2 and a third transistor T3. The gate of the second transistor T2 is connected to the first point g, the first electrode of the second transistor T2 is connected to the second point s, and the second transistor T2 is connected to the second point s. The electrode is connected to the cathode of the light emitting device 202, the gate of the third transistor T3 is connected to the second control signal EM, the first electrode of the third transistor T3 is connected to the second power signal VSS, and the second electrode of the third transistor T3 is connected to the Two-point s connection.

The detection module 204 includes a fourth transistor T4, a sensing line Sense-line, and a single-pole double-throw switch K. The gate of the fourth transistor T4 is connected to the third control signal RD, and the first electrode of the fourth transistor T4 is connected to the second point s , The second electrode of the fourth transistor T4 is connected to the first end of the sensing line Sense-line, the moving contact T of the single-pole double-throw switch K is connected to the second end of the sensing line Sense-line, and the first end of the single-pole double-throw switch K A static contact S1 is connected to the reference voltage VREF, and the second static contact S2 of the single-pole double-throw switch K is connected to the analog-to-digital converter ADC.

The storage module 205 includes a storage capacitor Cst, the first plate of the storage capacitor Cst is connected to the first point g, and the second plate of the storage capacitor Cst is connected to the second point s.

In this application, one of the first electrode and the second electrode of each transistor is the source and the other is the drain. The first power supply signal VDD is the power supply high potential signal, and the second power supply VSS is the power supply low potential signal. The output voltage value of a power signal VDD is greater than the voltage value output of the second power signal VSS. In the driving module 203, the second transistor T2 is a driving transistor, and the threshold voltage of the driving module 203 is the threshold voltage Vth of the second transistor T2.

As shown in FIG. 3, it is a timing diagram of each signal of the pixel driving circuit of FIG. 2 in the display phase. The display phase includes a data writing phase t1 and a light emitting phase t2.

In the data writing phase t1, the first control signal WR is at a high potential, the first transistor T1 is turned on, and the data line DATA inputs a high-level data signal to the first point g and the storage capacitor Cst. The first point g is equal to Vdata. The second control signal EM is at a high potential, the third transistor T3 is turned on, and the potential at the second point s is equal to VSS. At the end of this phase, the first transistor T1 works in a saturated state to drive the light emitting device 202 to emit light.

In the light-emitting phase t2, the first control signal WR is at a low level, the first transistor T1 is turned off, and the voltage Vdata of the data line cannot reach the gate of the second transistor T2, but due to the storage effect of the storage capacitor Cst, the gate of the second transistor T2 The pole voltage can still continue to maintain the data signal voltage Vdata, so that the second transistor T2 works in a saturated state, and the driving current enters the light emitting device 202 through the second transistor T2, thereby driving the light emitting device 202 to continuously emit light. After that, the pixel driving circuit continues to stage t2 until the next stage t1 comes.

In the data writing phase t1 and the light-emitting phase t2, the second control signal EM is high, and the third control signal RD is low. Therefore, the third transistor T3 is turned on, the fourth transistor T4 is turned off, and the transistors are turned on. The situation with the closure is shown in Figure 4.

The ability of the OLED to emit light is driven by the output current generated when the second transistor T2 is operating in a saturated state. Specifically, the output current (that is, the current flowing through the OLED) satisfies the formula:

I=K(Vgs-Vth) ²

Wherein, Vgs is the voltage difference between the gate of the second transistor T2 and the first electrode, Vth is the threshold voltage of the second transistor T2, and K is a constant related to the structure and process of the second transistor T2.

Since the second transistor T2 is in saturation during the light-emitting phase t2, the gate voltage of the second transistor T2 is Vdata, and the first electrode voltage of the second transistor T2 is VSS. For pixels in different gray levels, the value of Vdata is different, and Vgs It is also different, and Vth and K are fixed values. It can be seen from the above formula that the output current I is less affected by the change of Vgs. Therefore, in the light-emitting phase, in the pixel driving circuit corresponding to different pixels, the output terminal of the driving module 203, that is, the output of the second electrode of the second transistor T2 The current is in the preset range, and the preset range is relatively small.

In the prior art, the cathodes of the light-emitting devices are connected together, and the current flowing through the cathodes is controlled by the second power signal VSS. Because the pixel cathodes at different positions on the panel have different resistances to the collection point, specifically: The farther away from the input terminal of the second power signal VSS, the greater the resistance and the lower the voltage, which will cause the phenomenon of power supply voltage drop (IR-Drop). On a large-area display panel, IR-Drop will cause OLEDs in different positions There is a difference in the current on the panel, which in turn leads to uneven light emission of the panel, which affects the display quality of the image.

In the pixel driving circuit of the present application, the anodes of all light-emitting devices are connected together, and the cathodes are connected to the output terminal of the driving module 203. Since the second transistor T2 is in a saturated state during the light-emitting phase t2, the corresponding pixels of different pixels are In the pixel driving circuit, the current value of the output terminal of the driving module is in the preset range. Therefore, the current flowing through the cathodes of the light-emitting devices located at different positions of the OLED display panel is less affected by the voltage drop of the power supply, so that the OLED display panel The display brightness is uniform, which improves the display effect.

Due to the inhomogeneity in the transistor manufacturing process, the threshold voltage of the driving transistor of each pixel in the OLED display panel is not consistent. In addition, due to long-term operation and other reasons, the material of the driving transistor will age, resulting in the threshold voltage of the driving transistor drifting. In order to realize the normal display of the OLED display panel, the threshold voltage of the driving transistor needs to be detected and compensated. Therefore, the OLED display panel also needs to be detected before each startup or after the shutdown. This stage is the detection stage.

As shown in FIG. 5, it is a timing diagram of each signal of the pixel driving circuit of FIG. 2 in the detection phase. The detection phase includes an initialization phase t3, a charging phase t4, and a voltage detection phase t5.

In the initialization phase t3, the first control signal WR is at a high level, the first transistor T1 is turned on, and a high-level data signal Vdata is input to the first point g, the second control signal EM is at a low level, and the third transistor T3 is turned off. The control signal RD is at a high potential, the fourth transistor T4 is turned on, the moving contact T of the single-pole double-throw switch K is connected to the first static contact S1, and the reference voltage VREF is input to the second point s. At this time, the gate voltage of the second transistor T2 is Vdata, and the voltage of the first electrode of the second transistor T2 is VREF.

In the charging phase t4, the first control signal WR maintains a high potential, the first transistor T1 is turned on, the second control signal EM maintains a low potential, the third transistor T3 is turned off, the third control signal RD is maintained at a high potential, and the fourth transistor T4 is turned on. The moving contact T of the single-pole double-throw switch K is disconnected from the first static contact S1 and the second static contact S2. At this time, the voltage at the second point s continues to rise until Vs=Vdata-Vth.

In the voltage detection phase t5, the first control signal WR maintains a high level, the first transistor T1 is turned on, the second control signal EM maintains a low level, the third transistor T3 is turned off, the third control signal RD maintains a high level, and the fourth transistor T4 Open, the moving contact T of the single-pole double-throw switch K is connected to the second static contact S2. At this time, since the sensing line Sense-line is connected to the second point s, the voltage on the sensing line Sense-line is The voltage at the two points s is the same. The analog-to-digital converter ADC detects the voltage on the sensing line Sense-line, generates the corresponding data and latches it. The detected voltage value is the voltage value at the second point s at this time .

After the detection is completed, the data signal input in the display stage is adjusted according to the detected voltage SAMP, so as to realize the compensation for the driving transistor.

In the detection phase, the second control signal EM is always at a low level, so the second transistor T2 is always in the off state. In this phase, the switching conditions of each transistor are as shown in FIG. 6.

As shown in FIG. 7, it is a schematic diagram of the second structure of the pixel driving circuit provided by the embodiment of this application. The difference from the structure in FIG. 2 is that the pixel driving circuit further includes a switch module 206 connected to the cathode of the light-emitting device 202. The switch module 206 is used in the detection phase under the control of the fourth control signal VC, The connection between the light emitting device 202 and the driving module 203 is cut off.

Specifically, the switch module 206 includes a fifth transistor T5, the gate of the fifth transistor T5 is connected to the fourth control signal VC, the first electrode of the fifth transistor T5 is connected to the cathode of the light emitting device 202, and the second electrode of the fifth transistor T5 is connected to the cathode of the light emitting device 202. The electrode is connected to the first power signal VDD.

As shown in FIG. 8, it is a timing diagram of each signal in the display phase in the pixel driving circuit of FIG. 7. The display phase includes a data writing phase t1 and a light emitting phase t2. The switching situation of each transistor in the display stage is shown in Figure 9.

In this embodiment, the fourth control signal VC is always low during the data writing phase t1 and the light-emitting phase t2, so the fifth transistor T5 is always turned off. The timing of other signals is the same as that in FIG. 3, and the specific principles are also the same. I won't repeat them here.

As shown in FIG. 10, it is a timing diagram of each signal in the detection phase in the pixel driving circuit of FIG. 7. The detection phase includes an initialization phase t3, a charging phase t4, and a voltage detection phase t5. The switching conditions of each transistor in the detection phase are shown in Figure 11.

In this embodiment, the fourth control signal VC is always at a high level during the detection phase, so the fifth transistor T5 is always turned on. The timing of the other signals is the same as that in FIG. 5, and the specific principles are also the same, and will not be repeated here.

In the pixel driving circuit of FIG. 2, since in the initialization phase t3 of the detection phase, the first control signal WR is at a high potential, the first transistor T1 is turned on, the third control signal RD is at a high potential, and the fourth transistor T4 is turned on, and There is a voltage difference between the voltage of the first power signal VDD and the voltage of the second point s, so the current flows to the sensing line Sense-line through the first power signal VDD, the first transistor T1, and the fourth transistor T4, so that the light emitting device 202 A current flows and emits light, which eventually causes the screen to appear progressively scanned bright lines during detection.

In this embodiment, a fifth transistor T5 is added, and the second electrode of the fifth transistor T5 is connected to the first power signal VDD. After the fifth transistor T5 is turned on, the cathode and the anode of the light emitting device 202 are both connected to the A power signal VDD, therefore, has the same potential and no current flows, so that screen flicker does not occur during detection, and the quality of the OLED display panel is improved.

In the above embodiment, the first control signal WR, the second control signal EM, the third control signal RD, and the fourth control signal VC are all provided by an external timing device.

In the pixel driving circuit of the present application, the anodes of all light-emitting devices are connected together, and the cathodes are connected to the output terminal of the driving module. In the light-emitting phase, in the pixel driving circuit corresponding to different pixels, the current value of the output terminal of the driving module is all In the preset range, the current flowing through the cathodes of the light-emitting devices located at different positions of the OLED display panel is less affected by the voltage drop of the power supply, so that the display brightness of the OLED display panel is uniform.

The present application also provides an OLED display panel including a plurality of pixels and a pixel driving circuit for driving the pixels, wherein the pixel driving circuit is the pixel driving circuit described in any of the above embodiments. By using the pixel driving circuit provided by the embodiment of the present application, regardless of the distance, the cathode current of each light-emitting device is less affected by the voltage drop of the power supply, so that the display brightness of the OLED display panel is uniform.

According to the above embodiments:

The present application provides a pixel drive circuit and an OLED display panel. The pixel drive circuit includes a data signal input module, a light emitting device, a drive module, a detection module, and a storage module; the data signal input module is used in the data writing stage, in the first Under the control of the control signal, the data signal is input to the first point; the anode of the light emitting device is connected to the first power signal; the first input end of the driving module is connected to the data signal input module through the first point, and the second point of the driving module is connected to the data signal input module. The input terminal is connected with the second power signal, and the output terminal of the driving module is connected with the cathode of the light-emitting device. The driving module is used to drive the light-emitting device to emit light under the control of the second control signal and the potential of the first point; the detection module passes through the second The point is connected to the drive module, and is used to detect the threshold voltage of the drive module under the control of the third control signal in the detection phase; the storage module is connected to the drive module through the first point and the second point, and is used to store the drive module In the light-emitting phase, in the pixel driving circuit corresponding to different pixels, the current value of the output terminal of the driving module is in the preset range. In the pixel driving circuit of the present application, the anodes of all light-emitting devices are connected together, and the cathodes are connected to the output terminal of the driving module. In the light-emitting phase, in the pixel driving circuit corresponding to different pixels, the current value of the output terminal of the driving module is all In the preset range, the current flowing through the cathodes of the light-emitting devices located at different positions of the OLED display panel is less affected by the voltage drop of the power supply, so that the display brightness of the OLED display panel is uniform.

In the above-mentioned embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in an embodiment, reference may be made to related descriptions of other embodiments.

The above is a detailed introduction to a pixel driving circuit and an OLED display panel provided by the embodiments of the present application. Specific examples are used in this article to explain the principles and implementations of the present application. The descriptions of the above embodiments are only used to help understanding The technical solution of this application and its core idea; those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or equivalently replace some of the technical features; and these modifications or replacements , Does not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

A pixel driving circuit, which includes:

The data signal input module is used to input a data signal to the first point under the control of the first control signal during the data writing stage;

A light emitting device, the anode of the light emitting device is connected to the first power signal;

Drive module, the first input end of the drive module is connected to the data signal input module through the first point, the second input end of the drive module is connected to a second power signal, and the output end of the drive module Connected with the cathode of the light-emitting device, the driving module is configured to drive the light-emitting device to emit light under the control of a second control signal and the potential of the first point;

The detection module is connected to the drive module through the second point, and is used to detect the threshold voltage of the drive module under the control of a third control signal in the detection phase;

A storage module, connected to the driving module through the first point and the second point, and used to store the threshold voltage of the driving module;

In the light-emitting phase, in the pixel drive circuits corresponding to different pixels, the current values of the output terminals of the drive modules are all within a preset range.
8. The pixel driving circuit of claim 1, wherein the data signal input module comprises a first transistor, a gate of the first transistor is connected to the first control signal, and a first electrode of the first transistor Connected to the data line, and the second electrode of the first transistor is connected to the first point.
3. The pixel driving circuit of claim 2, wherein the light emitting device is an organic light emitting diode.
The pixel driving circuit of claim 3, wherein the driving module includes a second transistor and a third transistor, the gate of the second transistor is connected to the first point, and the first transistor of the second transistor is connected to the first point. The electrode is connected to the second point, the second electrode of the second transistor is connected to the cathode of the light emitting device, the gate of the third transistor is connected to the second control signal, and the second electrode of the third transistor is connected to the second control signal. The first electrode is connected to the second power signal, and the second electrode of the third transistor is connected to the second point.
8. The pixel driving circuit of claim 4, wherein, in the data writing phase and the light emitting phase, the second control signal is at a high potential.
8. The pixel driving circuit of claim 4, wherein, in the detection phase, the second control signal is at a low level.
8. The pixel driving circuit of claim 4, wherein the detection module includes a fourth transistor, a sensing line, and a single-pole double-throw switch, a gate of the fourth transistor is connected to the third control signal, and The first electrode of the fourth transistor is connected to the second point, the second electrode of the fourth transistor is connected to the first end of the sensing line, and the moving contact of the SPDT switch is connected to the sensing line At the second end of the single-pole double-throw switch, the first static contact of the single-pole double-throw switch is connected to a reference voltage, and the second static contact of the single-pole double-throw switch is connected to an analog-to-digital converter.
7. The pixel driving circuit of claim 7, wherein the detection module is used to control the connection between the moving contact of the SPDT switch and the first static contact during the initialization phase of the detection phase, In the voltage detection phase of the detection phase, the movable contact of the SPDT switch is controlled to be connected to the second static contact.
7. The pixel driving circuit of claim 7, wherein the storage module comprises a storage capacitor, a first plate of the storage capacitor is connected to the first point, and a second plate of the storage capacitor is connected to the The second point is connected.
9. The pixel drive circuit of claim 9, wherein the pixel drive circuit further comprises a switch module, the switch module is connected to the cathode of the light-emitting device, the switch module is used in the detection phase, in the fourth Under the control of the control signal, the connection between the light emitting device and the driving module is cut off.
The pixel driving circuit of claim 10, wherein the switch module comprises a fifth transistor, the gate of the fifth transistor is connected to the fourth control signal, and the first electrode of the fifth transistor is connected to the fourth control signal. The cathode of the light emitting device is connected, and the second electrode of the fifth transistor is connected to the first power signal.
11. The pixel driving circuit according to claim 11, wherein, in the data writing phase and the light emitting phase, the fourth control signal is at a low level.
11. The pixel driving circuit of claim 11, wherein, in the detection phase, the fourth control signal is at a high level.
11. The pixel driving circuit of claim 11, wherein the first control signal, the second control signal, the third control signal, and the fourth control signal are all provided by an external timing device.
An OLED display panel includes a plurality of pixels and a pixel drive circuit for driving the pixels, wherein the pixel drive circuit includes:

The data signal input module is used to input a data signal to the first point under the control of the first control signal during the data writing stage;

A light emitting device, the anode of the light emitting device is connected to the first power signal;

Drive module, the first input end of the drive module is connected to the data signal input module through the first point, the second input end of the drive module is connected to a second power signal, and the output end of the drive module Connected with the cathode of the light-emitting device, the driving module is configured to drive the light-emitting device to emit light under the control of a second control signal and the potential of the first point;

The detection module is connected to the drive module through the second point, and is used to detect the threshold voltage of the drive module under the control of a third control signal in the detection phase;

A storage module, connected to the driving module through the first point and the second point, and used to store the threshold voltage of the driving module;

In the light-emitting phase, in the pixel drive circuits corresponding to different pixels, the current values of the output terminals of the drive modules are all within a preset range.
15. The OLED display panel of claim 15, wherein the data signal input module comprises a first transistor, a gate of the first transistor is connected to the first control signal, and a first electrode of the first transistor Connected to the data line, and the second electrode of the first transistor is connected to the first point.
The OLED display panel of claim 16, wherein the light emitting device is an organic light emitting diode.
The OLED display panel of claim 17, wherein the driving module includes a second transistor and a third transistor, the gate of the second transistor is connected to the first point, and the first transistor of the second transistor is connected to the first point. The electrode is connected to the second point, the second electrode of the second transistor is connected to the cathode of the light-emitting device, the gate of the third transistor is connected to the second control signal, and the second electrode of the third transistor is connected to the second control signal. The first electrode is connected to the second power signal, and the second electrode of the third transistor is connected to the second point.
The OLED display panel of claim 18, wherein the detection module includes a fourth transistor, a sensing line, and a single-pole double-throw switch, the gate of the fourth transistor is connected to the third control signal, and the The first electrode of the fourth transistor is connected to the second point, the second electrode of the fourth transistor is connected to the first end of the sensing line, and the moving contact of the SPDT switch is connected to the sensing line At the second end of the single-pole double-throw switch, the first static contact of the single-pole double-throw switch is connected to a reference voltage, and the second static contact of the single-pole double-throw switch is connected to an analog-to-digital converter.
19. The OLED display panel of claim 19, wherein the storage module comprises a storage capacitor, a first plate of the storage capacitor is connected to the first point, and a second plate of the storage capacitor is connected to the first point. The second point is connected.