Pixel circuit, pixel driving method and display panel

Abstract

The application belongs to the technical field of display driving, and particularly relates to a pixel circuit, a pixel driving method and a display panel. The pixel circuit comprises a pixel driving module, which is used for responding to a scanning signal input on the scanning line and a data signal input on the data line, and outputting a corresponding target driving current; a light emitting module, which is used for emitting light with a corresponding brightness under the action of the target driving current; and a detection module, which is used for responding to a detection control signal input on the detection signal line in a detection period, and acquiring a detection voltage on the data detection node and a detection current flowing through the data detection node in time. Through the cooperative work of the pixel driving module, the light emitting module and the detection module, the real-time detection of key parameters is completed while normal display is maintained, and the detection accuracy of the pixel circuit is improved.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the technical field of display driving, and particularly relates to a pixel circuit, a pixel driving method and a display panel. BACKGROUND

[0002] AMOLED (Active Matrix Organic Light Emitting Diode) display technology is widely used in various display devices due to its self-luminous, high contrast, low power consumption and other advantages. The pixel circuit of the AMOLED display technology usually adopts a 2T1C structure, and the current of the driving transistor is controlled by the data voltage to adjust the luminance of the OLED. However, the electron mobility and threshold voltage of the driving transistor are not uniform in time and space, and the OLED itself will also age over time, resulting in a problem that the target gray scale does not meet the standard, which causes the display luminance to deviate from the expectation and affects the consistency of the picture quality.

[0003] In order to solve the above problem, the related technology usually adopts an external compensation method to compensate the pixel circuit, that is, the performance changes of the driving transistor and the OLED are fed back and compensated by detecting the voltage or current in the scanning period. However, the detection in the scanning period is limited by the RC load of the detection trace and the detection time, which causes the related technology to have the problem of low detection accuracy, affecting the compensation accuracy of the pixel circuit.

[0004] Therefore, how to improve the detection accuracy of the pixel circuit is a problem to be solved at present. SUMMARY

[0005] The present application provides a pixel circuit, a pixel driving method and a display panel, which solve the problem of low detection accuracy of the pixel circuit.

[0006] In a first aspect, the present application provides a pixel circuit, which comprises: a pixel driving module, the pixel driving module being connected with a scanning line and a data line respectively, and being configured to output a corresponding target driving current in response to a scanning signal input on the scanning line and a data signal input on the data line; a light emitting module, an input end of the light emitting module being connected with an output end of the pixel driving module through a data detection node, and the light emitting module being configured to emit light with a corresponding luminance under the action of the target driving current; and a detection module, the detection module being connected with the input end of the light emitting module through the data detection node, and the detection module being further connected with the pixel driving module and a detection signal line, and being configured to acquire a detection voltage on the data detection node and a detection current flowing through the data detection node in a time-sharing manner in response to a detection control signal input on the detection signal line in a detection period; wherein the detection period is located in a display period of the current row.

[0007] Optionally, the pixel driving module comprises a driving transistor, the driving transistor comprises a control terminal, a first terminal and a second terminal, and the second terminal of the driving transistor serves as an output terminal of the pixel driving module; the detection module comprises: a detection trigger unit, a first terminal of the detection trigger unit being connected with a detection trigger line, a second terminal of the detection trigger unit being connected with the first terminal of the driving transistor, and a third terminal of the detection trigger unit being connected with a detection trigger node, for charging a voltage on the detection trigger node to a target potential in response to a detection trigger signal input on the detection trigger line; a data writing unit, a control terminal of the data writing unit being connected with the detection trigger node, a first terminal of the data writing unit being connected with a detection data line, and a second terminal of the data writing unit being connected with the control terminal of the driving transistor through a data writing node, for controlling the driving transistor to output a corresponding detection current in response to a detection data signal input on the detection data line; a data collection unit, a control terminal of the data collection unit being connected with the detection trigger node, a first terminal of the data collection unit being connected with the data detection node, and a second terminal of the data collection unit being connected with a detection collection line, for outputting a detection voltage on the data detection node and a detection current flowing through the data detection node to the detection collection line in time under the action of the target potential on the detection trigger node; and a detection reset unit, a control terminal of the detection reset unit being connected with the scan line, a first terminal of the detection reset unit being connected with the detection trigger node, and a second terminal of the detection reset unit being connected with the detection collection line, for resetting the voltage on the detection trigger node under the action of a scan signal input on the scan line and a reset signal input on the detection collection line; wherein the detection signal line comprises the detection trigger line, the detection data line and the detection collection line.

[0008] Optionally, the pixel driving module comprises: a first transistor, a control terminal of the first transistor being connected with the scan line, a first terminal of the first transistor being connected with the data line, and a second terminal of the first transistor being connected with a data writing node; a second transistor, a control terminal of the second transistor being connected with the data writing node, a first terminal of the second transistor being connected with a power supply line, and a second terminal of the second transistor being connected with the data detection node; and a first capacitor, a first terminal of the first capacitor being connected with the data writing node, and a second terminal of the first capacitor being connected with the data detection node; wherein the second transistor is a driving transistor.

[0009] Optionally, the data collection unit comprises: a third transistor, a control terminal of the third transistor serving as the control terminal of the data collection unit, a first terminal of the third transistor serving as the first terminal of the data collection unit, and a second terminal of the third transistor serving as the second terminal of the data collection unit.

[0010] Optionally, the data writing unit comprises a fourth transistor, a control terminal of the fourth transistor serving as a control terminal of the data writing unit, a first terminal of the fourth transistor serving as a first terminal of the data writing unit, and a second terminal of the fourth transistor serving as a second terminal of the data writing unit.

[0011] Optionally, the detection triggering unit comprises a fifth transistor, a first terminal of the fifth transistor serving as a first terminal of the detection triggering unit, a control terminal of the fifth transistor being connected with the first terminal of the fifth transistor, and a second terminal of the fifth transistor serving as a third terminal of the detection triggering unit; and a second capacitor, a first terminal of the second capacitor serving as a second terminal of the detection triggering unit, and the second capacitor being connected with the second terminal of the fifth transistor.

[0012] Optionally, the detection resetting unit comprises a sixth transistor, a control terminal of the sixth transistor serving as a control terminal of the detection resetting unit, a first terminal of the sixth transistor serving as a first terminal of the detection resetting unit, and a second terminal of the sixth transistor serving as a second terminal of the detection resetting unit.

[0013] In a second aspect, the present application provides a pixel driving method applied to a pixel circuit, the pixel driving method comprising: in a scanning period, outputting a target driving current by a pixel driving module in response to a scanning signal on a scanning line and a data signal on a data line; in a display period, emitting light by a light emitting module under the action of the target driving current; and in a detection period, acquiring a detection voltage on a data detection node and a detection current flowing through the data detection node by a detection module in response to a detection control signal on a detection signal line.

[0014] Optionally, when the detection module includes a detection trigger unit, a data writing unit, a data acquisition unit, and a detection reset unit, the detection module responds to the detection control signal on the detection signal line to acquire the detection voltage on the data detection node and the detection current flowing through the data detection node in a time-division manner, including: during the detection period, the detection trigger unit, the data writing unit, and the data acquisition unit are continuously activated by the detection trigger signal input through the detection trigger line; during the first voltage measurement phase of the detection period, a first detection data signal is input through the detection data line, the first detection data signal is written to the data writing node through the data writing unit, and the first detection voltage on the data detection node is acquired through the data acquisition unit. Voltage; wherein, the first detected data signal is the data voltage corresponding to the current row in the current frame; during the current measurement phase of the detection period, a second detected data signal is input to the detection data line, and the second detected data signal is written to the data writing node through the data writing unit; a reference voltage is input to the detection acquisition line, and the detection current on the data detection node is obtained through the data acquisition unit; wherein, the voltage value of the second detected data signal is less than the turn-on voltage of the light-emitting module; during the second voltage measurement phase of the detection period, the second detected data signal is continuously input to the detection data line, the input of the reference voltage is disconnected on the detection acquisition line, and the second detected voltage on the data detection node is obtained through the data acquisition unit.

[0015] Thirdly, this application provides a display panel, the display panel including multiple scan lines and multiple data lines, the display panel further including: at least one detection signal line; an array of pixel circuits, the pixel circuits being electrically connected to the scan lines, the data lines and the detection signal line respectively; a timing controller, the timing controller being connected to the pixel circuits, used to obtain the operating parameters of the driving transistors and light-emitting modules in the pixel circuits according to the detection voltage and detection current output by the pixel circuits in a time-division manner, and to compensate the data signal according to the operating parameters.

[0016] The technical solution provided in this application has at least the following beneficial effects:

[0017] During the scanning period, this application generates a target driving current through the pixel driving module based on the input scanning signal and data signal, which drives the light-emitting module to emit light. During the detection period within the display period, the detection module is activated to acquire at least one detection voltage and detection current on the data detection node in a time-division manner. Therefore, through the coordinated work of the pixel driving module, the light-emitting module, and the detection module, this application achieves real-time detection of key parameters while maintaining normal display. Furthermore, by adopting a time-division measurement strategy, it achieves high-precision parameter detection while maintaining high-quality display, providing a solid foundation for subsequent accurate compensation. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0019] Figure 1 The diagram shows the basic pixel circuit of an OLED.

[0020] Figure 2 The diagram shows a pixel circuit with external compensation in the related technology.

[0021] Figure 3 The diagram shown is a schematic diagram of a pixel circuit provided in an embodiment of this application.

[0022] Figure 4 The diagram shown is a schematic diagram of the first pixel circuit provided in the embodiment of this application.

[0023] Figure 5 The diagram shown is a driving timing diagram provided in an embodiment of this application.

[0024] Figure 6 The diagram shown is a waveform representation of a detection period provided in an embodiment of this application.

[0025] Figure 7 The diagram shown is a schematic diagram of the first type of current flow provided in the embodiment of this application.

[0026] Figure 8 The diagram shown is a second current flow direction provided in an embodiment of this application.

[0027] Figure 9 The diagram shown is a schematic diagram of the second pixel circuit provided in an embodiment of this application.

[0028] Figure 10 The diagram shown is a flowchart of a pixel driving method provided in an embodiment of this application.

[0029] Explanation of reference numerals in the attached figures:

[0030] 100. Pixel circuit;

[0031] 110. Pixel driving module; 120. Light emission module; 130. Detection module; 131. Detection trigger unit; 132. Data writing unit; 133. Data acquisition unit; 134. Detection reset unit;

[0032] T1, first transistor; T2, second transistor; T3, third transistor; T4, fourth transistor; T5, fifth transistor; T6, sixth transistor; CST1, first capacitor; CST2, second capacitor; A, data write node; B, data detection node; C, detection trigger node; OLED, light-emitting diode. Detailed Implementation

[0033] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0034] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0035] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be noted that the technical features involved in the various embodiments described below can be combined with each other as long as they do not conflict with each other. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present application, and should not be construed as limiting the present application.

[0036] AMOLED (Active Matrix Organic Light Emitting Diode) is a new display technology that combines organic light-emitting diodes (OLEDs) and active matrix technology. AMOLED displays are characterized by their self-emissive nature, meaning they do not require a backlight and can display more vivid colors and deeper blacks. Because each pixel can emit light independently, AMOLED screens offer higher contrast and lower power consumption.

[0037] The basic circuit of OLED pixels, such as Figure 1As shown, the basic circuit is a 2T1C architecture. When the scan line is turned on, the first transistor T1 turns on, and the data voltage Vdata is input to point A. The voltage at point A then controls the current of the second transistor T2 (the driving transistor), causing the current to flow through the OLED and making it emit the brightness of the target grayscale. Due to the unevenness and drift of the electron mobility and threshold voltage Vth of the second transistor T2 in time and space, as well as the OLED aging and uneven aging problems, the target grayscale may not meet the standard. Therefore, compensation processing is often performed on the pixel circuit. The compensation methods are generally divided into internal compensation and external compensation. Since the internal compensation capability is limited, it is generally used in small-sized display devices. External compensation has the advantages of fewer TFTs and stronger compensation capability, and is widely used in large-sized display devices, and is gradually being applied to smaller sizes.

[0038] Figure 2 This is a schematic diagram of a pixel circuit with external compensation in related technologies. Figure 2 It is a commonly used 3T1C pixel circuit, relatively Figure 1 A third transistor T3 is added to the basic circuit. Its gate can be turned on by the current stage scan signal G(n) or an additional signal, so that the anode voltage B of the OLED is connected to the detection line to detect the voltage at point B or the current of the second transistor T2, thereby feeding back the change in the capability of the second transistor T2 and the OLED, and performing logic compensation accordingly. When to perform detection is crucial for external compensation. When detection occurs during the scanning period, the RC loading of the detection traces limits the single-line scanning time, resulting in insufficient voltage stability at point B and low detection accuracy. When detection occurs during the blanking period, the detection time can be artificially extended, but the voltage at point B is simultaneously affected by changes in the capability of the second transistor T2 and OLED aging. Only one factor can be assumed to remain constant to roughly calculate the change in the other factor, and the detection accuracy remains low. When detection is performed while the display is forcibly stopped, display factors can be disregarded, and the detection time can be artificially extended to create conditions for detecting the voltage at point B, the current of the second transistor T2, and the OLED current. This method offers strong detection capabilities, a wide range of detection content, and high accuracy, but the drawback is that it requires stopping the display, affecting the user experience.

[0039] Therefore, in order to solve the above problems, this application provides a pixel circuit, specifically including the following embodiments:

[0040] Figure 3 The diagram shown is a schematic representation of a pixel circuit according to an embodiment of this application; as shown Figure 1 As shown, the pixel circuit 100 includes a pixel driving module 110, which is connected to the scan line and the data line respectively, and is used to respond to the scan signal input on the scan line and the data signal input on the data line, and output the corresponding target driving current.

[0041] It should be noted that, in this embodiment, the pixel driving module 110 acts as a signal conversion unit, responding to the scanning signal on the scan line during the scanning period, receiving the data signal on the data line, and converting it into a corresponding target driving current. The magnitude of this driving current precisely corresponds to the desired display grayscale, and is maintained stably within the frame period through an internal storage mechanism. The pixel driving module 110 ensures the accuracy and stability of the display brightness, providing a reliable current reference for the subsequent light-emitting module 120.

[0042] In this embodiment, the pixel circuit 100 further includes a light-emitting module 120. The input terminal of the light-emitting module 120 is connected to the output terminal of the pixel driving module 110 through the data detection node B, and is used to emit light of corresponding brightness under the action of the target driving current.

[0043] Specifically, in this embodiment, the light-emitting module 120 receives the driving current from the pixel driving module 110 through the data detection node B and converts it into light output of corresponding brightness. The data detection node B, as a key point in the current path, carries both display and detection functions. In this embodiment, the light-emitting module 120 realizes the basic display function of electro-optic conversion. At the same time, through the ingenious setting of the data detection node B, a non-intrusive measurement access point is provided for parameter detection, ensuring that the detection process does not affect the normal display effect.

[0044] In this embodiment, the pixel circuit 100 further includes a detection module 130. The detection module 130 is connected to the input terminal of the light-emitting module 120 through the data detection node B. The detection module 130 is also connected to the pixel driving module 110 and the detection signal line. During the detection period, it responds to the detection control signal input on the detection signal line and acquires the detection voltage on the data detection node B and the detection current flowing through the data detection node B in a time-division manner. The detection period is located within the display period of the current row.

[0045] It should be noted that the detection module 130 is activated during specific detection periods within the display period. Responding to control signals on the detection signal line, it acquires at least one detection voltage on the data detection node B and measures the detection current flowing through the data detection node B in multiple time periods. This allows the subsequent circuit to calculate the current state parameters of the driving transistor in the pixel driving module 110 and the OLED in the light-emitting module 120 based on at least one detection voltage and detection current, and performs data compensation based on these current state parameters. This embodiment, by acquiring the detection voltage and current parameters in a time-division manner, can isolate the influence of various factors, significantly improving the accuracy of parameter identification and measurement precision. Furthermore, detection is performed within the display period, ensuring the real-time nature and representativeness of the parameter data.

[0046] It should also be noted that in this embodiment, the detection period is set within the display period after the current row scan ends. At this time, the pixel circuit 100 is in a stable display state, but has not yet entered the scanning cycle of the next frame. This timing arrangement ensures that the detection operation is carried out when the circuit is in a stable working state, thereby achieving the following technical effects: (1) It makes full use of the time window of the display period and avoids the problem of limited detection time in traditional methods; (2) It ensures that the detection parameters can truly reflect the circuit characteristics under the actual display state; (3) It achieves true real-time compensation and can track the changes of parameters with time and temperature in a timely manner; (4) It minimizes the impact on the display effect, and the user is completely unaware of the existence of the detection process.

[0047] Therefore, during the scanning period, the pixel driving module 110 generates a target driving current based on the input scanning signal and data signal, which drives the light-emitting module 120 to emit light. During the detection period within the display period, the detection module 130 is activated to acquire at least one detection voltage and detection current on the data detection node B in a time-division manner. Thus, the pixel circuit 100 of this embodiment, through the coordinated operation of the pixel driving module 110, the light-emitting module 120, and the detection module 130, completes real-time detection of key parameters while maintaining normal display. Furthermore, by adopting a time-division measurement strategy, it achieves high-precision parameter detection while maintaining high-quality display, providing a solid foundation for subsequent accurate compensation.

[0048] like Figure 3 As shown, the pixel driving module 110 includes a driving transistor, which includes a control terminal, a first terminal, and a second terminal. The second terminal of the driving transistor serves as the output terminal of the pixel driving module 110. The detection module 130 includes a detection trigger unit 131, the first terminal of which is connected to a detection trigger line, the second terminal of which is connected to the first terminal of the driving transistor, and the third terminal of which is connected to a detection trigger node C. The detection trigger unit 131 is used to charge the voltage on the detection trigger node C to the target potential in response to a detection trigger signal input on the detection trigger line.

[0049] It should be noted that the detection trigger unit 131, as the initiation module of the detection process, responds to the signal on the detection trigger line at the start of the detection period. This unit charges the detection trigger node C to a specific target potential, which remains stable throughout the detection period, providing a control reference for subsequent data writing and data acquisition operations. A stable detection control environment is established through the detection trigger unit 131, ensuring that subsequent operations are performed under defined voltage conditions. Furthermore, through an independent triggering mechanism, precise start and stop control of the detection process is achieved, avoiding interference with the normal display timing.

[0050] In this embodiment, the detection module 130 further includes a data writing unit 132. The control terminal of the data writing unit 132 is connected to the detection trigger node C. The first terminal of the data writing unit 132 is connected to the detection data line. The second terminal of the data writing unit 132 is connected to the control terminal of the driving transistor through the data writing node A. It is used to respond to the detection data signal input on the detection data line and control the driving transistor to output the corresponding detection current.

[0051] It should be noted that the data writing unit 132 in this embodiment is controlled by the potential of the detection trigger node C. Based on the specific signal input on the detection data line, it configures the operating state of the driving transistor. By adjusting the control terminal voltage of the driving transistor, it outputs a current signal that meets the detection requirements. The data writing unit 132 achieves precise control of the operating point of the driving transistor, creating optimal conditions for subsequent parameter measurements. Through flexible voltage configuration, it can adapt to driving transistors with different characteristics, enhancing the system's adaptability and detection accuracy.

[0052] In this embodiment, the detection module 130 further includes a data acquisition unit 133. The control terminal of the data acquisition unit 133 is connected to the detection trigger node C, the first terminal of the data acquisition unit 133 is connected to the data detection node B, and the second terminal of the data acquisition unit 133 is connected to the detection acquisition line. It is used to output the detection voltage on the data detection node B and the detection current flowing through the data detection node B to the detection acquisition line in a time-division manner under the action of the target point on the detection trigger node C.

[0053] It should be noted that, under the control of the potential of the detection trigger node C, the data acquisition unit 133 performs the measurement task in multiple stages: first, it acquires the detection voltage on the data detection node B at different time periods, and then measures the detection current flowing through the node; the measurement results are output to the external processing circuit through the detection acquisition line. The time-division measurement strategy of the data acquisition unit 133 in this embodiment effectively avoids mutual interference between voltage and current measurements, ensures the integrity of the measurement signal through a dedicated acquisition channel, and provides accurate and separate parameter data for the external compensation algorithm, greatly improving the compensation effect.

[0054] In this embodiment, the detection module 130 further includes a detection reset unit 134. The control terminal of the detection reset unit 134 is connected to the scan line, the first terminal of the detection reset unit 134 is connected to the detection trigger node C, and the second terminal of the detection reset unit 134 is connected to the detection acquisition line. It is used to reset the voltage on the detection trigger node C under the action of the scan signal input on the scan line and the reset signal input on the detection acquisition line.

[0055] It should be noted that, under the combined action of the scanning signal and the reset signal, the detection reset unit 134 performs a reset operation on the detection trigger node C at the end of each frame display. This process is precisely synchronized with the scanning timing of the next frame, ensuring that the detection system returns to its initial state. This ensures the periodicity and repeatability of the detection process, prevents measurement deviations caused by charge accumulation, achieves seamless connection between the detection system and the display system, and ensures the stability of the system operation.

[0056] In addition, the detection signal lines in this embodiment include detection trigger lines, detection data lines, and detection acquisition lines. Under the coordination of an external timing controller, these three types of signal lines send control signals according to a precise time sequence, directing each functional unit to work in an orderly manner. The specialized division of labor of signals improves the system control accuracy, reduces crosstalk and conflicts between signals, and provides reliable timing guarantees for complex multi-stage detection processes.

[0057] Therefore, it can be seen that the pixel driving module 110 in this embodiment establishes a connection with multiple functional units of the detection module 130 through the driving transistor, and through these functional units working together in a specific timing sequence during the detection period, the characteristic parameters of the driving transistor are accurately extracted.

[0058] Figure 4 The diagram shown is a circuit diagram of the first pixel circuit 100 provided in an embodiment of this application; as shown Figure 4 As shown, the pixel driving module 110 includes a first transistor T1, a second transistor T2, and a first capacitor CST1; the control terminal of the first transistor T1 is connected to the scan line, the first end of the first transistor T1 is connected to the data line, and the second end of the first transistor T1 is connected to the data writing node A; the control terminal of the second transistor T2 is connected to the data writing node A, the first end of the second transistor T2 is connected to the power line, and the second end of the second transistor T2 is connected to the data detection node B; the first end of the first capacitor CST1 is connected to the data writing node A, and the second end of the first capacitor CST1 is connected to the data detection node B.

[0059] In this embodiment, the light-emitting module 120 is an OLED (Light Emitting Diode).

[0060] It should be noted that the second transistor T2 is a driving transistor; this embodiment takes the first transistor T1 and the second transistor T2 as N-type MOS transistors as an example to explain the working principle of the pixel driving module 110:

[0061] (1) During the scanning period of the current row, a high-level scanning signal is output on the scanning line, turning on the first transistor T1 and establishing a connection path between the data line and the data writing node A. At this time, the data signal transmitted on the data line is written to the data writing node A and stored in the first capacitor CST1. At the same time, the high level on the data writing node A is applied to the control terminal of the second transistor T2 (driving transistor), thereby completing the fast and accurate writing of the display data.

[0062] (2) After entering the current row display period, the scan signal switches to a low level, and the first transistor T1 is turned off. At this time, the first capacitor CST1 plays a key role, using its charge storage characteristics to continuously maintain the voltage stability on the data writing node A throughout the entire display period. This voltage holding capability ensures the constant potential of the drive transistor control terminal, creating the necessary conditions for stable current output.

[0063] In this embodiment, the second transistor T2, acting as the driving transistor, continuously generates a corresponding driving current based on the stable voltage maintained at its control terminal. This driving current flows from the power line through the second transistor T2 to the data detection node B, ultimately driving the light-emitting module 120 to operate. The current conversion process of the pixel driving module 110 follows the basic principle of field-effect transistors, accurately converting the stored voltage signal into the corresponding current output.

[0064] like Figure 4 As shown, the data acquisition unit 133 in this embodiment includes a third transistor T3. The control terminal of the third transistor T3 serves as the control terminal of the data acquisition unit 133, the first terminal of the third transistor T3 serves as the first terminal of the data acquisition unit 133, and the second terminal of the third transistor T3 serves as the second terminal of the data acquisition unit 133.

[0065] The data writing unit 132 in this embodiment includes a fourth transistor T4. The control terminal of the fourth transistor T4 serves as the control terminal of the data writing unit 132, the first terminal of the fourth transistor T4 serves as the first terminal of the data writing unit 132, and the second terminal of the fourth transistor T4 serves as the second terminal of the data writing unit 132.

[0066] The detection trigger unit 131 in this embodiment includes a fifth transistor T5 and a second capacitor CST2. The first terminal of the fifth transistor T5 serves as the first terminal of the detection trigger unit 131, and the control terminal of the fifth transistor T5 is connected to the first terminal of the fifth transistor T5. The second terminal of the fifth transistor T5 serves as the third terminal of the detection trigger unit 131. The first terminal of the second capacitor CST2 serves as the second terminal of the detection trigger unit 131, and the second capacitor CST2 is connected to the second terminal of the fifth transistor T5.

[0067] The detection and reset unit 134 in this embodiment includes a sixth transistor T6. The control terminal of the sixth transistor T6 serves as the control terminal of the detection and reset unit 134, the first terminal of the sixth transistor T6 serves as the first terminal of the detection and reset unit 134, and the second terminal of the sixth transistor T6 serves as the second terminal of the detection and reset unit 134.

[0068] It should be noted that this embodiment uses the third transistor T3, the fourth transistor T4, the fifth transistor T5, and the sixth transistor T6 as N-type MOS transistors as an example. Figure 5 and Figure 6 The timing diagram is used to explain the working principle of the detection module 130:

[0069] 1. For example Figure 5 As shown, the detection period in this embodiment is located at the end of each frame display period. Taking the nth row as an example, as... Figure 6 The waveform diagram shown in the diagram illustrates that before the gate drive signal Gn of the next frame arrives, the start of the entire detection period is controlled by the detection trigger signal Kn output by the detection trigger line. The detection trigger signal Kn has a certain advance time relative to the gate drive signal Gn, which determines the duration of the entire detection period. When the detection trigger signal Kn is high, the detection trigger node C can be charged through the turned-on fifth transistor T5. Under the maintenance effect of the second capacitor CST2, the detection trigger node C remains high throughout the entire detection period, allowing the third transistor T3 and the fourth transistor T4 to remain on continuously.

[0070] 2. For example Figure 6 As shown, the detection period in this embodiment is divided into three phases: Phase 1, Phase 2, and Phase 3. Different phases implement different detection functions. During the detection process, it is necessary to coordinate the detection data signal Vin input on the detection data line and the detection signal Vsense input on the detection acquisition line to realize the detection of voltage and current output on the detection acquisition line. The specific process is as follows:

[0071] (1) In stage one (i.e., the first voltage measurement stage): the detection data signal Vin input to the detection data line is the data voltage of the current frame, i.e., V1=Vdata, so that the data writing node A maintains the current grayscale in this stage, instead of other fixed voltages, thereby avoiding affecting the display. At the same time, the driving of the detection signal Vsense input to the detection acquisition line is divided into two time periods, t1 and t2. During time period t1, the detection acquisition line is actively driven externally, and the first reference voltage Vref1 is input. After t1, the external output is disconnected, and the in-plane driving is used. That is, under the driving of the second transistor T2, the third transistor T3 charges the detection acquisition line. After t2, the output voltage on the detection acquisition line reaches equilibrium, and then the balanced voltage Vout1 is detected and recorded during time period t3.Figure 6 During process t2, the gate of the second transistor T2 is the data writing node A, and the voltage V1 of the data writing node A is the data voltage Vdata of the current frame. Therefore, the voltage of the anode of the light-emitting diode (i.e., the data detection node B) is determined by the following formula:

[0072] Formula ①: Drive current of the second transistor T2 ;in, The channel width of the second transistor T2, The channel length of the second transistor T2 For electrical mobility, The capacitance per unit area of ​​a transistor MIS structure. This is the threshold voltage of the second transistor T2.

[0073] Formula ②: OLDE current: ;in, This is the equivalent resistance of the OLED.

[0074] Because the external input is disconnected during process t2, the steady state is affected. And at this time, the detection voltage on the data detection node B is detected by the external circuit. Let this be denoted as Vout1, and the current direction is as follows: Figure 7 As shown. Therefore, the t2 time period needs to be set to a certain duration so that To achieve equilibrium, a time period t1 is set to pre-charge the detection and acquisition line with approximately equal capacitance. This is done to prevent parasitic capacitance on the acquisition line from affecting the time required to reach equilibrium. The voltage is the first reference voltage Vref1, in order to shorten the time period t2. Therefore, formulas ① and ② can be converted to:

[0075] Formula ③: ;

[0076] The above formula contains three unknowns: TFT electron mobility. TFT threshold voltage OLED equivalent resistance The above three parameters differ spatially and drift over time, all of which affect the current flowing through the OLED. Therefore, these three values ​​are the main objects of detection.

[0077] (2) In stage two (i.e., the current measurement stage): the input detection data signal Vin on the detection data line is V2. V2 is lower than the minimum turn-on voltage of the OLED, so the voltage of the data writing node A is V2, which makes the OLED not emit light, thus avoiding affecting the display. During this period, a second reference voltage Vref2 is input to the externally driven detection and acquisition line, thereby enabling... The second reference voltage Vref2 should be lower than V2-Vth, so that the second transistor T2 remains on and current flows through it. The current flows only through the third transistor T3 to the detection and acquisition line, and the current direction is as follows: Figure 8 As shown. At this time, the current can be detected by an external circuit. Therefore, we have:

[0078] Formula ④: .

[0079] (3) In stage three (i.e., the second pressure measurement stage), V2 is continuously input on the detection data line, causing the OLED to not emit light, and During this period, the external input on the detection and acquisition line is disconnected. The voltage on the detection and acquisition line continues as described above during period t5 until it reaches equilibrium. During time period T6, the voltage at node B is detected by an external circuit via a detection acquisition line. Let Vout2 be the value of Vout2. At this point, we have:

[0080] Formula ⑤: Therefore, formula ⑥ can be derived: .

[0081] (4) After the above three stages, formulas ③, ④ and ⑥ are obtained respectively, and the TFT electron mobility can be solved. TFT threshold voltage OLED equivalent resistance Once the above parameter values ​​are obtained, real-time compensation can be performed by modifying the data voltage.

[0082] 3. After the above detection period ends, the scanning signal Gn of the next frame is turned on. The data signal of the next frame is written through the data writing node A of the first transistor T1, and the sixth transistor T6 is turned on. The detection acquisition line is driven by the outside. A low level is given to reset it, which clears the voltage on the detection trigger node C and starts normal display.

[0083] Therefore, the three stages mentioned above are compressed into a single detection period, placed at the end of the current display. This detection period does not alter or stop the OLED display state. Furthermore, by pre-charging the detection acquisition lines externally, the detection time can be significantly shortened, thus having no negative impact on the display. Since the compensation objective is to maintain the OLED acquiring the target current, formula ④ can be expressed as the TFT electron mobility... TFT threshold voltage The current variation caused by unevenness or drift can be compensated for by adjusting the TFT electron mobility. TFT threshold voltage Furthermore, formula ③ can be used to further express the non-uniformity or drift of the OLED equivalent resistance R; therefore, stages one and two can achieve the same compensation effect, and the addition of stage three can specifically calculate the real-time values ​​of each parameter. Specific implementation can be carried out according to requirements. The detection trigger signal Kn in this embodiment can be generated using an additional GOA.

[0084] It should be noted that the pixel circuit 100 shown in the above embodiments is designed using N-type transistors, but it can also be designed using P-type transistors, specifically including the following embodiments:

[0085] Figure 9 The diagram shown is a circuit diagram of the second pixel circuit 100 provided in an embodiment of this application; as shown Figure 9 As shown, all transistors are P-type MOS transistors, and their connection methods are all the same as... Figure 4 The embodiments shown are the same, and the detection time period is the same. Figure 5 The logic and detection location are the same (but the P-type MOSFET is turned on at a low level), and the specific control logic for the detection period is different. Figure 6 The logic is basically the same (but the turn-on condition for the P-type MOSFET is low level); the difference is that this embodiment omits... Figure 6 The reason for the third stage in the process is that the entire pTFT pair cannot extract the Vth of the TFT in the third stage; the specific working principle is as follows:

[0086] (1) Although the logic of Phase 1 and Phase 2 of the above detection period is the same as that of the above embodiment, Figure 6 The formulas are the same, but due to the differential voltage in the pTFT saturation current calculation formula, the calculation formulas differ. Formula ① in the above embodiment should be:

[0087] Formula ⑦: ;

[0088] Therefore, compared to formula ③ in the above embodiment, the change is:

[0089] Formula ⑧: ;

[0090] The formula ④ in the above embodiment should be changed as follows:

[0091] Formula ⑨: .

[0092] It should be noted that since stage three is not included, specific numerical values ​​cannot be calculated. However, the same values ​​for TFT carrier mobility can be obtained using formulas ⑧ and ⑨ as in the above embodiments. TFT threshold voltage OLED equivalent resistance Detection compensation is performed. The aforementioned nTFTs include devices such as a-Si and IGZO, and pTFTs include devices such as LTPS. This application is also compatible with LTPO backplanes shared by both types of devices, and the control logic is the same.

[0093] In summary, the embodiments provided in this application can detect changes in the driving transistor's capability and OLED aging during the display period, and have the advantages of comprehensive detection content, high detection accuracy, real-time detection, and no adverse effects on the display.

[0094] In one embodiment, this application provides a pixel driving method, specifically including the following embodiments:

[0095] Figure 10 The diagram shown is a flowchart of a pixel driving method provided in an embodiment of this application; as follows: Figure 10 As shown, this pixel driving method is applied to the pixel circuit shown in the above embodiment, and specifically includes the following steps:

[0096] Step S100: During the scanning period, the pixel driving module responds to the scanning signal on the scanning line and the data signal on the data line, and outputs the target driving current.

[0097] Step S200: During the display period, the light-emitting module emits light under the action of the target driving current.

[0098] Step S300: During the detection period, the detection module responds to the detection control signal on the detection signal line to acquire the detection voltage on the data detection node and the detection current flowing through the data detection node in a time-division manner.

[0099] In one embodiment, when the detection module includes a detection trigger unit, a data writing unit, a data acquisition unit, and a detection reset unit, it responds to the detection control signal on the detection signal line to acquire the detection voltage on the data detection node and the detection current flowing through the data detection node in a time-division manner, including:

[0100] During the detection period, the detection trigger signal input through the detection trigger line continuously activates the detection trigger unit, data writing unit, and data acquisition unit;

[0101] During the first voltage measurement phase of the detection period, the first detection data signal is input to the detection data line, and the first detection data signal is written to the data writing node through the data writing unit. The first detection voltage on the data detection node is obtained through the data acquisition unit. The first detection data signal is the data voltage corresponding to the current row in the current frame.

[0102] During the current measurement phase of the detection period, a second detection data signal is input to the detection data line and written to the data writing node through the data writing unit; a reference voltage is input to the detection acquisition line and the detection current on the data detection node is obtained through the data acquisition unit; wherein, the voltage value of the second detection data signal is less than the turn-on voltage of the light-emitting module;

[0103] During the second voltage measurement phase of the detection period, the second detection data signal is continuously input into the detection data line, the input of the reference voltage is disconnected from the detection acquisition line, and the second detection voltage at the data detection node is obtained through the data acquisition unit.

[0104] It should be noted that the working principle of the pixel driving method provided in this embodiment is the same as that of the pixel circuit in the above embodiment, and will not be repeated here.

[0105] In one embodiment, this embodiment provides a display panel, the display panel including:

[0106] Multiple scan lines and multiple data lines;

[0107] At least one detection signal line;

[0108] The pixel circuits shown in the above embodiments of the array arrangement are electrically connected to scan lines, data lines and detection signal lines, respectively.

[0109] The timing controller is connected to the pixel circuit and is used to obtain the operating parameters of the driving transistor and light-emitting module in the pixel circuit according to the detection voltage and detection current output by the pixel circuit in a time-division manner, and to compensate the data signal according to the operating parameters.

[0110] Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0111] In the description of this specification, references to terms such as "some embodiments," "exemplarily," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. The illustrative expressions of the above terms in this specification do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0112] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application. Therefore, any changes or modifications made in accordance with the claims and description of this application should fall within the scope of this patent application.

Claims

1. A pixel circuit, characterized in that, The pixel circuit includes: A pixel driving module is connected to a scan line and a data line respectively, and is used to respond to a scan signal input on the scan line and a data signal input on the data line, and output a corresponding target driving current; wherein, the pixel driving module includes a driving transistor, the driving transistor includes a control terminal, a first terminal and a second terminal, and the second terminal of the driving transistor serves as the output terminal of the pixel driving module; The light-emitting module has its input end connected to the output end of the pixel driving module via a data detection node, and is used to emit light of corresponding brightness under the action of the target driving current; The detection module is connected to the input terminal of the light-emitting module through the data detection node. The detection module is also connected to the pixel driving module and the detection signal line. During the detection period, it responds to the detection control signal input on the detection signal line and acquires the detection voltage on the data detection node and the detection current flowing through the data detection node in a time-division manner. The detection module includes: A detection trigger unit, wherein a first end of the detection trigger unit is connected to a detection trigger line, a second end of the detection trigger unit is connected to a first end of the driving transistor, and a third end of the detection trigger unit is connected to a detection trigger node, for responding to a detection trigger signal input on the detection trigger line and charging the voltage on the detection trigger node to the target potential; A data writing unit, wherein the control terminal of the data writing unit is connected to the detection trigger node, the first terminal of the data writing unit is connected to the detection data line, and the second terminal of the data writing unit is connected to the control terminal of the driving transistor through the data writing node, for responding to the detection data signal input on the detection data line and controlling the driving transistor to output a corresponding detection current; A data acquisition unit, wherein the control terminal of the data acquisition unit is connected to the detection trigger node, the first terminal of the data acquisition unit is connected to the data detection node, and the second terminal of the data acquisition unit is connected to the detection acquisition line, and is used to output the detection voltage on the data detection node and the detection current flowing through the data detection node to the detection acquisition line in a time-division manner under the action of the target point on the detection trigger node. A detection and reset unit is provided, wherein the control terminal of the detection and reset unit is connected to the scan line, the first terminal of the detection and reset unit is connected to the detection trigger node, and the second terminal of the detection and reset unit is connected to the detection acquisition line. The unit is used to reset the voltage on the detection trigger node under the action of the scan signal input on the scan line and the reset signal input on the detection acquisition line. The detection period is located within the display period of the current row, and the detection signal line includes the detection trigger line, the detection data line, and the detection acquisition line.

2. The pixel circuit according to claim 1, characterized in that, The pixel driving module includes: A first transistor, wherein the control terminal of the first transistor is connected to the scan line, the first terminal of the first transistor is connected to the data line, and the second terminal of the first transistor is connected to the data writing node; The second transistor has a control terminal connected to the data writing node, a first terminal connected to the power supply line, and a second terminal connected to the data detection node. A first capacitor, the first end of which is connected to the data writing node, and the second end of which is connected to the data detection node; The second transistor is a driving transistor.

3. The pixel circuit according to claim 1, characterized in that, The data acquisition unit includes: The third transistor has its control terminal serving as the control terminal of the data acquisition unit, its first terminal serving as the first terminal of the data acquisition unit, and its second terminal serving as the second terminal of the data acquisition unit.

4. The pixel circuit according to claim 1, characterized in that, The data writing unit includes: The fourth transistor has a control terminal that serves as the control terminal of the data writing unit, a first terminal that serves as the first terminal of the data writing unit, and a second terminal that serves as the second terminal of the data writing unit.

5. The pixel circuit according to claim 1, characterized in that, The detection triggering unit includes: The fifth transistor has a first terminal serving as the first terminal of the detection trigger unit, a control terminal connected to the first terminal of the fifth transistor, and a second terminal of the fifth transistor serving as the third terminal of the detection trigger unit. The second capacitor has its first terminal serving as the second terminal of the detection trigger unit, and is connected to the second terminal of the fifth transistor.

6. The pixel circuit according to claim 1, characterized in that, The detection reset unit includes: The sixth transistor has a control terminal that serves as the control terminal of the detection and reset unit, a first terminal that serves as the first terminal of the detection and reset unit, and a second terminal that serves as the second terminal of the detection and reset unit.

7. A pixel driving method, characterized in that, The pixel driving method, applied to the pixel circuit according to any one of claims 1-6, comprises: During the scanning period, the pixel driving module responds to the scanning signal on the scan line and the data signal on the data line, and outputs the target driving current. During the display period, the light-emitting module emits light under the action of the target driving current; During the detection period, the detection module responds to the detection control signal on the detection signal line to acquire the detection voltage on the data detection node and the detection current flowing through the data detection node in a time-division manner.

8. The pixel driving method according to claim 7, characterized in that, When the detection module includes a detection trigger unit, a data writing unit, a data acquisition unit, and a detection reset unit, it responds to the detection control signal on the detection signal line to acquire the detection voltage on the data detection node and the detection current flowing through the data detection node in a time-division manner, including: During the detection period, the detection triggering signal input through the detection triggering line continuously activates the detection triggering unit, the data writing unit, and the data acquisition unit; During the first voltage measurement phase of the detection period, a first detection data signal is input to the detection data line, and the first detection data signal is written to the data writing node through the data writing unit. The first detection voltage on the data detection node is obtained through the data acquisition unit. The first detection data signal is the data voltage corresponding to the current row in the current frame. During the current measurement phase of the detection period, a second detection data signal is input to the detection data line, and the second detection data signal is written to the data writing node through the data writing unit; a reference voltage is input to the detection acquisition line, and the detection current on the data detection node is obtained through the data acquisition unit; wherein, the voltage value of the second detection data signal is less than the turn-on voltage of the light-emitting module; During the second voltage measurement phase of the detection period, the second detection data signal is continuously input into the detection data line, the input of the reference voltage is disconnected from the detection acquisition line, and the second detection voltage at the data detection node is obtained through the data acquisition unit.

9. A display panel, the display panel comprising a plurality of scan lines and a plurality of data lines, characterized in that, The display panel also includes: At least one detection signal line; The pixel circuit according to any one of claims 1-6 is arranged in an array, wherein the pixel circuit is electrically connected to the scan line, the data line and the detection signal line respectively; A timing controller, connected to the pixel circuit, is used to obtain the operating parameters of the driving transistor and the light-emitting module in the pixel circuit based on the detection voltage and detection current output by the pixel circuit in a time-division manner, and to compensate the data signal based on the operating parameters.

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