Pixel driving circuit, display panel and light-emitting control method

Abstract

The invention discloses a pixel driving circuit, a display panel and a light emitting control method, and belongs to the technical field of display. The pixel driving circuit comprises a signal write-in sub-circuit (20) which provides a data voltage and a signal of a reference signal end to a grid electrode of a driving transistor (DTFT) in a time-sharing manner, the gray scale of the data voltage is a high gray scale, the driving transistor (DTFT) generates a driving current according to the data voltage, a light-emitting control sub-circuit (10) responds to a signal of a light-emitting control end (EM), and the light-emitting control sub-circuit (10) emits light to the grid electrode of the driving transistor (DTFT). The brightness control sub-circuit (30) responds to a signal of a data gating end (GateT) and provides a signal of a power supply signal end (ELVDD) to a driving transistor (DTFT), the brightness control sub-circuit (30) responds to a signal of a data gating end (GateT) and provides a reference data signal of a reference data end (DataT) to a grid electrode of the driving transistor (DTFT), and the voltage of the reference data signal is the same as the data voltage, so that driving current continues to be provided to a light-emitting device (LED), or the brightness control sub-circuit (30) responds to a signal of a data gating end (GateT). When the voltage of the reference data signal is smaller than the threshold voltage of the driving transistor (DTFT), the driving transistor (DTFT) stops providing the driving current for the light-emitting device (LED), so that the photoelectric conversion efficiency is improved, and the phenomenon of non-uniform picture color and brightness is improved.

Description

Pixel driving circuit, display panel and light emitting control method Technical Field

[0001] The present application relates to the field of display technology and provides a pixel driving circuit, a display panel and a light emitting control method. Background Art

[0002] As LED size decreases, defects in the LED manufacturing process increase the proportion of photoelectric efficiency degradation, resulting in very low photoelectric conversion efficiency for micro LEDs. During the display process, low photoelectric efficiency and uneven color and brightness at low current densities prevent the direct use of pixel driver circuits in related technologies for micro LEDs.

[0003] Summary of the Invention

[0004] The embodiments of the present application provide a pixel driving circuit, a display panel, and a light emitting control method to improve the photoelectric conversion efficiency of related LEDs and improve the problem of uneven color and brightness during the display process.

[0005] The specific technical solutions provided in this application are as follows:

[0006] In a first aspect, an embodiment of the present application provides a pixel driving circuit, comprising: a driving transistor, a light-emitting device, a light-emitting control subcircuit, a signal writing subcircuit, and a brightness control subcircuit;

[0007] The signal writing sub-circuit is coupled to the gate of the driving transistor and is configured to provide the data voltage and the signal of the reference signal terminal to the gate of the driving transistor in a time-sharing manner, wherein the gray scale of the data voltage is a high gray scale;

[0008] The second terminal of the driving transistor is coupled to the light emitting device and is configured to generate a driving current according to the data voltage;

[0009] The light emitting control subcircuit is coupled to the first terminal of the driving transistor and is configured to provide a signal from the power signal terminal to the first terminal of the driving transistor in response to a signal from the light emitting control terminal;

[0010] The brightness control subcircuit is coupled to the gate of the driving transistor and is configured to provide a reference data signal from the reference data terminal to the gate of the driving transistor in response to a signal from the data selection terminal, wherein the voltage of the reference data signal is the same as the data voltage so that the driving current generated by the driving transistor continues to be provided to the light-emitting device, or the voltage of the reference data signal is less than the threshold voltage of the driving transistor so that the driving transistor stops providing the driving current to the light-emitting device.

[0011] Optionally, the brightness control subcircuit includes: a first transistor;

[0012] The control terminal of the first transistor is coupled to the data strobe terminal, the first terminal of the first transistor is coupled to the reference data terminal, and the second terminal of the first transistor is coupled to the gate of the driving transistor.

[0013] Optionally, the signal writing sub-circuit includes: a second transistor;

[0014] The control end of the second transistor is coupled to the scan signal end, the first end of the second transistor is coupled to the data signal end, and the second end of the second transistor is coupled to the gate of the driving transistor.

[0015] Optionally, the signal writing sub-circuit includes: a third transistor and a fourth transistor;

[0016] A control terminal of the third transistor is coupled to the scan signal terminal, a first terminal of the third transistor is coupled to the data signal terminal, and a second terminal of the third transistor is coupled to the gate of the driving transistor;

[0017] The control terminal of the fourth transistor is coupled to the reset reference signal terminal, the first terminal of the fourth transistor is coupled to the reference signal terminal, and the second terminal of the fourth transistor is coupled to the gate of the driving transistor.

[0018] Optionally, the light emitting control subcircuit includes: a fifth transistor;

[0019] The control end of the fifth transistor is coupled to the light emitting control end, the first end of the fifth transistor is coupled to the power signal end, and the second end of the fifth transistor is coupled to the first end of the driving transistor.

[0020] Optionally, it further includes: a first capacitor and a second capacitor;

[0021] A first terminal of the first capacitor is coupled to the gate of the driving transistor, and a second terminal of the first capacitor is coupled to the anode of the light emitting device;

[0022] A first terminal of the second capacitor is coupled to the power signal terminal, and a second terminal of the second capacitor is coupled to the anode of the light emitting device.

[0023] Optionally, the device further comprises: a third capacitor;

[0024] A first terminal of the third capacitor is coupled to the gate of the driving transistor, and a second terminal of the third capacitor is coupled to the anode of the light emitting device.

[0025] Optionally, a reset subcircuit is further included;

[0026] The reset sub-circuit is coupled to the second end of the first capacitor and is configured to provide a signal from the initialization signal end to the second end of the first capacitor in response to a signal from the reset signal end.

[0027] Optionally, the reset sub-circuit includes: a sixth transistor;

[0028] The control terminal of the sixth transistor is coupled to the reset signal terminal, the first terminal of the sixth transistor is coupled to the anode of the light emitting device, and the second terminal of the sixth transistor is coupled to the initialization signal terminal.

[0029] In a second aspect, an embodiment of the present application further provides a display panel comprising any of the above-mentioned pixel driving circuits.

[0030] In a third aspect, the embodiments of the present application further provide a light emission control method, including:

[0031] The signal writing sub-circuit is coupled to the gate of the driving transistor and is configured to provide the data voltage and the signal of the reference signal terminal to the gate of the driving transistor in a time-sharing manner, wherein the gray scale of the data voltage is a high gray scale;

[0032] The second terminal of the driving transistor is coupled to the light emitting device and is configured to generate a driving current according to the data voltage;

[0033] The light emitting control subcircuit is coupled to the first terminal of the driving transistor and is configured to provide a signal from the power signal terminal to the first terminal of the driving transistor in response to a signal from the light emitting control terminal;

[0034] The brightness control subcircuit is coupled to the gate of the driving transistor and is configured to provide a reference data signal from the reference data terminal to the gate of the driving transistor in response to a signal from the data selection terminal, wherein the voltage of the reference data signal is the same as the data voltage so that the driving current generated by the driving transistor continues to be provided to the light-emitting device, or the voltage of the reference data signal is less than the threshold voltage of the driving transistor so that the driving transistor stops providing the driving current to the light-emitting device.

[0035] The beneficial effects of this application are as follows:

[0036] In summary, embodiments of the present application provide a pixel driving circuit, a display panel, and a light emitting control method. The pixel driving circuit includes: a signal writing subcircuit coupled to the gate of a driving transistor and configured to provide a data voltage and a signal at a reference signal terminal to the gate of the driving transistor in a time-sharing manner, wherein the grayscale of the data voltage is a high grayscale; a second terminal of the driving transistor coupled to the light emitting device and configured to generate a driving current based on the data voltage; a light emitting control subcircuit coupled to the first terminal of the driving transistor and configured to provide a signal at a power signal terminal to the first terminal of the driving transistor in response to a signal at a light emitting control terminal; a brightness control subcircuit coupled to the gate of the driving transistor and configured to provide a reference data signal at a reference data terminal to the gate of the driving transistor in response to a signal at a data strobe terminal; wherein the voltage of the reference data signal is the same as the data voltage so that the driving current generated by the driving transistor continues to be provided to the light emitting device, or the voltage of the reference data signal is less than a threshold voltage of the driving transistor so that the driving transistor stops providing the driving current to the light emitting device. The above-mentioned method of using the data voltage corresponding to the high grayscale to generate the driving current improves the photoelectric conversion efficiency of each transistor and effectively improves the phenomenon of uneven color and brightness of the picture.

[0037] Other features and advantages of the present application will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present application. The purposes and other advantages of the present application can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0039] FIG1 is a connection diagram of a pixel driving circuit in an embodiment of the present application;

[0040] FIG2 is a circuit connection diagram of a pixel driving circuit in an embodiment of the present application;

[0041] FIG3 is a timing diagram of a pixel driving circuit according to an embodiment of the present application;

[0042] FIG4 is a circuit connection diagram of another pixel driving circuit in an embodiment of the present application;

[0043] FIG5 is a timing diagram of another pixel driving circuit according to an embodiment of the present application;

[0044] FIG6 is a flow chart of a light emitting control method according to an embodiment of the present application. DETAILED DESCRIPTION

[0045] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of the technical solutions of this application, but not all of them. Based on the embodiments described in this application document, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the technical solutions of this application.

[0046] The terms "first," "second," and the like in the description and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the present invention described herein can be practiced using orders other than those illustrated or described herein.

[0047] In related technologies, the size of LEDs used in displays is shrinking. As LED size decreases, the photoelectric properties of LEDs—high photoelectric conversion efficiency at high current density and low photoelectric conversion efficiency at low current density—are affected. This can lead to, for example, uneven brightness and color shift during display. In particular, defects in the manufacturing process of small-sized LEDs (e.g., micro LEDs) can significantly reduce the photoelectric efficiency, leading to lower photoelectric conversion efficiency and making current pixel driver circuits incapable of direct application in display panels using small-sized LEDs.

[0048] The preferred embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0049] 1 , a pixel driving circuit proposed in an embodiment of the present application includes: a driving transistor DTFT, a light-emitting device L1 , a light-emitting control subcircuit 10 , a signal writing subcircuit 20 , and a brightness control subcircuit 30 .

[0050] The signal writing sub-circuit 20 is coupled to the gate of the driving transistor DTFT and is configured to provide the data voltage and the signal of the reference signal terminal Vref to the gate of the driving transistor DTFT in a time-sharing manner, wherein the grayscale of the data voltage is a high grayscale.

[0051] The signal writing sub-circuit 20 in the embodiment of the present application has two functions: one is to provide the signal of the reference signal terminal Vref to the gate of the driving transistor DTFT to reset the gate of the driving transistor DTFT; the other is to provide the data voltage to the gate of the driving transistor DTFT. It should be noted that the voltage of the signal of the above-mentioned reference signal terminal Vref is less than the value of the above-mentioned data voltage.

[0052] During implementation, the signal writing sub-circuit 20 first provides the signal of the reference signal terminal Vref to the gate of the driving transistor DTFT. Since the voltage of the signal of the reference signal terminal Vref is lower than the data voltage, the gate of the driving transistor DTFT is reset.

[0053] After resetting the gate of the driving transistor DTFT, the signal writing sub-circuit 20 supplies the data voltage to the gate of the driving transistor DTFT, causing the driving transistor DTFT to generate a driving current based on the data voltage. It should be noted that the grayscale of the data voltage is a high grayscale, i.e., the grayscale of the data voltage is between 200 and 255. This data voltage generates a high conversion efficiency of the driving current, resulting in a more uniform color and brightness of the displayed image.

[0054] Specifically, the second terminal of the driving transistor DTFT is coupled to the light emitting device L1 and is configured to generate a driving current according to the data voltage.

[0055] During implementation, the driving transistor DTFT generates a driving current under the action of the above-mentioned data voltage. It should be noted that, in order to make the above-mentioned generated driving current more accurate, in the embodiment of the present application, the threshold voltage of the driving transistor DTFT is also obtained, and the driving current is further generated under the action of the above-mentioned data voltage and the threshold voltage.

[0056] The light emitting control sub-circuit 10 is coupled to the first terminal of the driving transistor DTFT and is configured to provide a signal from the power signal terminal ELVDD to the first terminal of the driving transistor DTFT in response to a signal from the light emitting control terminal EM.

[0057] During implementation, when the signal at the light-emitting control terminal EM is a high voltage, the light-emitting control sub-circuit 10 is turned on, and the signal at the power signal terminal ELVDD is provided to the first terminal of the driving transistor DTFT via the turned-on light-emitting control sub-circuit 10. Under the action of the power signal terminal ELVDD, the driving transistor DTFT provides the above-mentioned driving current to the light-emitting device L1, so that the light-emitting device L1 emits light. It should be noted that the grayscale of the data voltage corresponding to the above-mentioned driving current is a high grayscale.

[0058] In the embodiments of the present application, different grayscales are achieved by adjusting the current and the luminous time. During implementation, if the driving current is at a medium or high grayscale, the luminous time of a frame includes two periods; if the driving current is at a low grayscale, the luminous time of a frame includes only one period. It should be emphasized that even if the driving current is at a low grayscale, the embodiments of the present application still use a high grayscale driving current to achieve medium and low grayscales, but the luminous time of the above driving current is reduced, thereby avoiding the defects of color shift and unstable brightness under low current LED.

[0059] It should be noted that, generally, one of the two time periods is the light-emitting period corresponding to the light-emitting control subcircuit 10, and the other is the period corresponding to the brightness control subcircuit 30. The specific durations of the two time periods are set according to the circuit configuration, including but not limited to the specific durations corresponding to the two time periods being equal.

[0060] The brightness control sub-circuit 30 is coupled to the gate of the driving transistor DTFT and is configured to provide a reference data signal from the reference data terminal DataT to the gate of the driving transistor DTFT in response to a signal from the data strobe terminal GateT, wherein the voltage of the reference data signal is the same as the data voltage, so that the driving current generated by the driving transistor DTFT continues to be provided to the light-emitting device L1.

[0061] During implementation, when the signal at the data strobe terminal GateT is at a high voltage, the brightness control sub-circuit 30 is turned on, and the reference data signal at the reference data terminal DataT is provided to the gate of the driving transistor DTFT via the turned-on brightness control sub-circuit 30. It should be noted that to achieve the display requirements of medium and high grayscale images, that is, to achieve the image display during the aforementioned other time period, the voltage of the reference data signal is the same as the data voltage, so that the drive current generated by the driving transistor DTFT continues to be provided to the light-emitting device L1.

[0062] Alternatively, in order to meet the display requirements of low grayscale images, that is, the image is displayed only during the period when the above-mentioned light-emitting control sub-circuit 10 is turned on, and the image corresponding to the above-mentioned other period is not displayed when the brightness control sub-circuit 30 is turned on, the above-mentioned brightness control sub-circuit 30 is turned on, and the reference data signal of the above-mentioned reference data terminal DataT is provided to the gate of the driving transistor DTFT via the turned-on brightness control sub-circuit 30, the voltage of the above-mentioned reference data signal is less than the threshold voltage of the driving transistor DTFT, that is, the driving transistor DTFT is turned off in the other period, so that the driving transistor DTFT stops providing driving current to the light-emitting device L1.

[0063] The following describes in detail the structure of transistors in each sub-circuit with reference to the accompanying drawings. Referring to FIG. 2 , the brightness control sub-circuit 30 includes: a first transistor T1 .

[0064] The connection relationship between the first transistor T1 and other components in Figure 2 is: the control end of the first transistor T1 is coupled to the data selection end GateT, the first end of the first transistor T1 is coupled to the reference data end DataT, and the second end of the first transistor T1 is coupled to the gate of the driving transistor DTFT.

[0065] During implementation, when the signal at the data selection terminal GateT is a high voltage, the first transistor T1 is turned on, and the reference data signal of the reference data terminal DataT is provided to the gate of the driving transistor DTFT via the turned-on first transistor T1, so that the driving transistor DTFT continues to generate a driving current under the action of the above-mentioned reference data signal and provides it to the light-emitting device L1. In this way, after the light-emitting device L1 emits light at the moment corresponding to the light-emitting control subcircuit 10, it continues to emit light at the moment when the above-mentioned first transistor T1 is turned on. Since the voltage of the reference data signal is the same as the data voltage, medium and high grayscale display of the picture can be achieved.

[0066] Correspondingly, when the signal of the data selection terminal GateT is a high voltage, the first transistor T1 is turned on, and the reference data signal of the reference data terminal DataT is provided to the gate of the driving transistor DTFT through the turned-on first transistor T1. However, in this case, the voltage of the reference data signal is less than the threshold voltage of the driving transistor DTFT, and the driving transistor DTFT is turned off. In this way, after the light-emitting device L1 emits light at the moment corresponding to the light-emitting control sub-circuit 10, it will not continue to emit light at the moment when the above-mentioned first transistor T1 is turned on. Although the gray scale of the data voltage corresponding to the driving current in the above-mentioned light-emitting process is a high gray scale, the light-emitting time is shortened, thereby enabling low gray scale display of the picture.

[0067] In one embodiment, referring to FIG. 2 , the signal writing sub-circuit 20 includes: a second transistor T2 .

[0068] The connection relationship between the second transistor T2 and other components in Figure 2 is: the control end of the second transistor T2 is coupled to the scan signal end Gate, the first end of the second transistor T2 is coupled to the data signal Data, and the second end of the second transistor T2 is coupled to the gate of the driving transistor DTFT.

[0069] During implementation, when the signal at the scanning signal terminal Gate is a high voltage, the second transistor T2 is turned on, and the data signal Data is provided to the gate of the driving transistor DTFT via the turned-on second transistor T2.

[0070] In another embodiment, referring to FIG. 3 , the signal writing sub-circuit 20 includes a third transistor T3 and a fourth transistor T4 .

[0071] The connection relationship between the third transistor T3 and other components in Figure 3 is: the control end of the third transistor T3 is coupled to the scan signal end Gate, the first end of the third transistor T3 is coupled to the data signal Data, and the second end of the third transistor T3 is coupled to the gate of the driving transistor DTFT.

[0072] During implementation, when the signal at the scanning signal terminal Gate is a high voltage, the third transistor T3 is turned on, and the data signal Data is provided to the gate of the driving transistor DTFT via the turned-on third transistor T3.

[0073] The connection relationship between the fourth transistor T4 and other components in Figure 3 is: the control end of the fourth transistor T4 is coupled to the reset reference signal end Vref, the first end of the fourth transistor T4 is coupled to the reference signal end Vref, and the second end of the fourth transistor T4 is coupled to the gate of the driving transistor DTFT.

[0074] During implementation, when the signal at the reset reference signal terminal Vref is a high voltage, the fourth transistor T4 is turned on, and the signal at the reference signal terminal Vref is provided to the gate of the driving transistor DTFT via the turned-on fourth transistor T4, thereby resetting the gate of the driving transistor DTFT.

[0075] 2 and 3 , the light emitting control sub-circuit 10 includes a fifth transistor T5 .

[0076] The connection relationship between the fifth transistor T5 and other components in Figures 2 and 3 is: the control end of the fifth transistor T5 is coupled to the light-emitting control end EM, the first end of the fifth transistor T5 is coupled to the power signal end ELVDD, and the second end of the fifth transistor T5 is coupled to the first end of the driving transistor DTFT.

[0077] During implementation, when the signal at the light emitting control terminal EM is a high voltage, the fifth transistor T5 is turned on, and the signal at the power signal terminal ELVDD is provided to the first terminal of the driving transistor DTFT via the turned-on fifth transistor T5.

[0078] In addition, in one embodiment, referring to FIG. 2 , the pixel driving circuit further includes: a first capacitor C1 and a second capacitor C2 .

[0079] The connection relationship between the first capacitor C1 and other components in FIG2 is as follows: a first end of the first capacitor C1 is coupled to the gate of the driving transistor DTFT, and a second end of the first capacitor C1 is coupled to the anode of the light emitting device L1.

[0080] During implementation, the first capacitor C1 is provided between the gate of the driving transistor DTFT and the anode of the light emitting device L1 , and the threshold voltage of the driving transistor DTFT is obtained through the voltage stabilization function of the first capacitor C1 .

[0081] 2 , the connection relationship between the second capacitor C2 and other components in FIG2 is as follows: a first terminal of the second capacitor C2 is coupled to the power signal terminal ELVDD, and a second terminal of the second capacitor C2 is coupled to the anode of the light emitting device L1.

[0082] During implementation, the second capacitor C2 is provided between the power signal terminal ELVDD and the anode of the light emitting device L1 , and the driving current is obtained through the loop formed by the first capacitor C1 and the second capacitor C2 .

[0083] In another embodiment, referring to FIG. 3 , the pixel driving circuit further includes a third capacitor C3 .

[0084] The connection relationship between the third capacitor C3 and other components in FIG3 is as follows: a first end of the third capacitor C3 is coupled to the gate of the driving transistor DTFT, and a second end of the third capacitor C3 is coupled to the anode of the light emitting device L1.

[0085] During implementation, the third capacitor C3 is provided between the gate of the driving transistor DTFT and the anode of the light emitting device L1 , and the driving current is obtained through the loop formed by the third capacitor C3 .

[0086] 2 and 3 , the pixel driving circuit further includes a reset sub-circuit 40 .

[0087] The reset sub-circuit 40 is coupled to the second end of the first capacitor C1 and is configured to provide a signal from the initialization signal terminal Vinit to the second end of the first capacitor C1 in response to a signal from the reset signal terminal Reset.

[0088] During implementation, the reset sub-circuit 40 resets the anode of the light emitting device L1 under the action of the signal of the reset signal terminal Reset.

[0089] 2 and 3 , the reset sub-circuit 40 includes a sixth transistor T6 .

[0090] The connection relationship between the sixth transistor T6 and other components in Figure 2 or Figure 3 is: the control end of the sixth transistor T6 is coupled to the reset signal end Reset, the first end of the sixth transistor T6 is coupled to the anode of the light-emitting device L1, and the second end of the sixth transistor T6 is coupled to the initialization signal end Vinit.

[0091] During implementation, when the signal at the reset signal terminal Reset is a high voltage, the sixth transistor T6 is turned on, and the signal at the initialization signal terminal Vinit is provided to the anode of the light emitting device L1 via the turned-on sixth transistor T6, thereby resetting the anode of the light emitting device L1.

[0092] The working process of the pixel driving circuit in the embodiment of the present application is described in detail below with reference to FIG. 2 and FIG. 4 .

[0093] Timing T1 stage: Reset = 1, Gate = 1, EM = 0, Data = 0, GateT = 0, DataT = 0, Id (L) = 0, Id (H) = 0

[0094] When the reset signal terminal Reset is at a high voltage, the signal at the initialization signal terminal Vinit is supplied to the anode of the light-emitting device to reset the anode of the light-emitting device. That is, the voltage at node N1 is the voltage value of Vinit. When the scan signal terminal Gate is at a high voltage, the signal at the reference signal terminal is supplied to the gate of the driving transistor to reset the gate of the driving transistor. It should be noted that in Figure 2, the reference signal terminal is multiplexed with the data signal terminal. That is, the signal at the data signal terminal in time sequence T1 is Vref.

[0095] Timing T2 stage: Reset = 0, Gate = 1, EM = 1, Data = 0, GateT = 0, DataT = 0, Id (L) = 0, Id (H) = 0

[0096] When the signal at the scan signal terminal Gate is high, the second transistor remains on, and the voltage at node N2 is Vref. When the signal at the emission control terminal EM is high, the fifth transistor is turned on, and the signal at the power signal terminal ELVDD is supplied to the first terminal of the driving transistor, turning the driving transistor off. The voltage at node N1 becomes the voltage at node N2 minus the threshold voltage of the driving transistor. This means that the threshold voltage of the driving transistor is obtained by utilizing the voltage stabilization effect of the first capacitor.

[0097] Timing T3 stage: Reset = 0, Gate = 1, EM = 0, Data = 1, GateT = 0, DataT = 0, Id (L) = 0, Id (H) = 0

[0098] When the scan signal terminal Gate is high, the data signal terminal Data provides the gate of the driving transistor with a signal Vdata. The voltage at node N1 jumps to (Vref - Vth) + (VData - Vref) * C2 / (C1 + C2). The jump voltage at node N2 is VData - Vref. The jump voltage at node N1 is the voltage divided by capacitors C1 / C2.

[0099] Timing T4 stage: Reset = 0, Gate = 0, EM = 1, Data = 0, GateT = 0, DataT = 0, Id(L) = 1, Id(H) = 1

[0100] The signal of the light emitting control terminal EM is a high voltage, the fifth transistor is turned on, and the current branch from the power signal terminal ELVDD to ELVSS is turned on. According to the saturation current formula: Id=K(Vgs-Vth) 2 , K=1 / 2μW / Lcox, K is a constant, and the driving current is Id=K(VData–Vref+Vth-(VData-Vref)*C2 / (C1+C2)-Vth)2 =K[Cst*(VData-Vref) / (C1+C2)] 2 .

[0101] Timing T5 stage: Reset = 0, Gate = 0, EM = 0, Data = 0, GateT = 1, DataT = 1, Id (L) = 0, Id (H) = 0

[0102] When the signal at the data strobe terminal GateT is high, the reference data signal DataT at the reference data terminal is input to node N2. The voltage jump amount at node N2 is DataT-VData. The jump voltage at node N1 is the voltage divided by the first capacitor C1 and the second capacitor C2. At this time, the jump voltage of node N1 is Vref-Vth+(DataT-Vref)*C2 / (C1+C2). If the display is in a medium or high grayscale and continues to emit light, the DataT voltage input during timing T5 is the same as the VData level input during timing T3. If the display is in a low grayscale, the DataT voltage input during timing T5 is lower than the threshold voltage of the driver transistor, and the driver transistor is cut off, stopping further light emission.

[0103] The working process of the pixel driving circuit in the embodiment of the present application is described in detail below with reference to FIG. 3 and FIG. 5 .

[0104] Timing stage t1: EM=0,Reset=1,GateC=1,Gate=0,Data=0,GataT=0,DataT=0,Id(L)=0,Id(H)=0

[0105] When the signal at the reset signal terminal Reset is at a high voltage, the signal at the initialization signal terminal Vinit is provided to the anode of the light-emitting device to reset the anode of the light-emitting device. That is, the voltage at the node N1 is equal to the voltage value of Vinit. When the signal at the reset reference signal terminal GateC is at a high voltage, the fourth transistor is turned on, and the signal Vref at the reference signal terminal is provided to the gate of the driving transistor to reset the gate of the driving transistor.

[0106] Timing t2 stage: EM=1,Reset=0,GateC=1,Gate=0,Data=0,GataT=0,DataT=0,Id(L)=0,Id(H)=0

[0107] When the signal at the reset reference signal terminal GateC remains high, the fourth transistor remains on, and the voltage at node N2 is Vref. When the signal at the emission control terminal EM is high, the fifth transistor is turned on, and the signal at the power supply signal terminal ELVDD is supplied to the first terminal of the driver transistor, turning the driver transistor off. The voltage at node N1 becomes the voltage at node N2 minus the threshold voltage of the driver transistor. This means that the threshold voltage of the driver transistor is obtained by utilizing the voltage stabilization effect of the third capacitor.

[0108] Timing t3 stage: EM=0,Reset=0,GateC=0,Gate=1,Data=1,GataT=0,DataT=0,Id(L)=0,Id(H)=0

[0109] When the signal at the scan signal terminal Gate is high, the third transistor turns on, and the signal Vdata at the data signal terminal Data is supplied to the gate of the driving transistor. The voltage at node N2 jumps from Vref at the previous moment to VData by a voltage jump of ΔV = VData - Vref. According to the charge retention theorem, node N1 also jumps by the same amount: from Vref - Vth at the previous moment to Vref - Vth + ΔV * C1 / (C1 + C_LED) = Vref - Vth + (VData - Vref) * C1 / (C1 + C_LED), where C_LED is the capacitance of the driving transistor.

[0110] Timing stage t4: EM=1,Reset=0,GateC=0,Gate=0,Data=0,GataT=0,DataT=0,Id(L)=1,Id(H)=1

[0111] The signal of the light emitting control terminal EM is a high voltage, the fifth transistor is turned on, and the current branch from the power signal terminal ELVDD to ELVSS is turned on. According to the saturation current formula: Id=K(Vgs-Vth) 2 , K=1 / 2μW / Lcox, K is a constant, and the driving current is Id=K(V_ N2 -V_ N1 -Vth) 2 =K[(VData-Vref)*C_LED / (C_LED+C1)] 2 .

[0112] Timing stage t5: EM=0,Reset=0,GateC=0,Gate=1,Data=0,GataT=1,DataT=1,Id(L)=0,Id(H)=0

[0113] When the signal at the data strobe terminal GateT is high, the reference data signal DataT at the reference data terminal is input to node N2. The voltage jump amount at node N2 is DataT-VData. The jump voltage at node N1 is the voltage divided by the first capacitor C1 and the second capacitor C2. At this time, the jump voltage of node N1 is Vref-Vth+(DataT-Vref)*C2 / (C1+C2). If the display is in a medium or high grayscale and continues to emit light, the DataT voltage input during timing T5 is the same as the VData level input during timing T3. If the display is in a low grayscale, the DataT voltage input during timing T5 is lower than the threshold voltage of the driver transistor, and the driver transistor is cut off, stopping further light emission.

[0114] Timing stage t6: EM=1,Reset=0,GateC=0,Gate=0,Data=0,GataT=0,DataT=0,Id(L)=0,Id(H)=1

[0115] The signal at the light-emitting control terminal EM is a high voltage, the fifth transistor is turned on, and the current branch from the power signal terminal ELVDD to ELVSS is turned on. When the timing t5 is for continued light emission, the reference data signal DataT at the reference data terminal is a high voltage, and the reference data signal DataT voltage is provided to the gate of the driving transistor. Since the voltage of the reference data signal is the same as the data voltage, the driving transistor continues to emit light at a high grayscale voltage.

[0116] Based on the same inventive concept, an embodiment of the present application provides a display panel comprising any of the above-mentioned pixel driving circuits.

[0117] In the embodiments of the present invention, the display panel can be any product or component with a display function, such as a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a digital photo frame, or a navigation system. Other essential components of the display panel are well understood by those skilled in the art and are not described in detail here, nor should they be construed as limiting the present invention.

[0118] Based on the same inventive concept, an embodiment of the present application provides a light emitting control method, as shown in FIG6 , including:

[0119] Step 201: The signal writing sub-circuit provides the data voltage and the signal of the reference signal terminal to the gate of the driving transistor in a time-sharing manner, wherein the gray scale of the data voltage is a high gray scale.

[0120] After the display of the previous frame is completed, the gate of the driving transistor and the anode of the light-emitting device are reset first. In one embodiment, when the signal at the scanning signal end is valid (for example, a high voltage), the signal writing sub-circuit is turned on, and the signal at the reference signal end is first provided to the gate of the driving transistor, and the gate of the driving transistor is reset by the signal at the reference signal end.

[0121] In another embodiment, the reset sub-circuit is coupled to the second terminal of the first capacitor and is configured to provide a signal from the initialization signal terminal to the second terminal of the first capacitor in response to a signal from the reset signal terminal. Specifically, when the signal from the reset signal terminal is valid (e.g., a high voltage), the reset sub-circuit is turned on, and the signal from the initialization signal terminal is first provided to the gate of the driver transistor, thereby resetting the gate of the driver transistor via the signal from the initialization signal terminal.

[0122] Afterwards, the signal writing sub-circuit provides the data voltage to the gate of the driving transistor when the signal at the scanning signal terminal is valid.

[0123] Step 202: driving the transistor to generate a driving current according to the data voltage.

[0124] During implementation, the driving transistor generates a driving current according to the data voltage. To further improve the accuracy of the driving current, the threshold voltage of the driving transistor can be obtained. In this way, the driving transistor can generate a driving current according to the data voltage and the threshold voltage.

[0125] Step 203: The light emitting control sub-circuit provides the signal from the power signal terminal to the first terminal of the driving transistor in response to the signal from the light emitting control terminal.

[0126] During implementation, when the signal at the light emitting control terminal is valid, the light emitting control sub-circuit is turned on, and the signal at the power signal terminal is provided to the first terminal of the driving transistor via the turned-on light emitting control sub-circuit.

[0127] Step 204: The brightness control subcircuit provides a reference data signal from the reference data terminal to the gate of the driving transistor in response to the signal from the data selection terminal, wherein the voltage of the reference data signal is the same as the data voltage so that the driving current generated by the driving transistor continues to be provided to the light-emitting device, or the voltage of the reference data signal is less than the threshold voltage of the driving transistor so that the driving transistor stops providing the driving current to the light-emitting device.

[0128] In an embodiment of the present application, when realizing the display of medium and high grayscale images, when the signal of the data selection terminal is valid, the brightness control sub-circuit is turned on, and the reference data signal of the reference data terminal is provided to the gate of the driving transistor through the turned-on brightness control sub-circuit. Since the voltage of the reference data signal is the same as the data voltage, the driving current generated by the driving transistor can continue to be provided to the light-emitting device after the light-emitting stage.

[0129] In order to achieve low grayscale image display, when the signal at the data selection end is valid, the brightness control sub-circuit is turned on, and the reference data signal at the reference data end is provided to the gate of the driving transistor through the turned-on brightness control sub-circuit. Since the voltage of the reference data signal is less than the threshold voltage of the driving transistor, the driving transistor is turned off, and the driving transistor stops providing driving current to the light-emitting device.

[0130] In summary, embodiments of the present application provide a pixel driving circuit, a display panel, and a light emitting control method. The pixel driving circuit includes: a signal writing subcircuit coupled to the gate of a driving transistor and configured to provide a data voltage and a signal at a reference signal terminal to the gate of the driving transistor in a time-sharing manner, wherein the grayscale of the data voltage is a high grayscale; a second terminal of the driving transistor coupled to a light emitting device and configured to generate a driving current based on the data voltage; a light emitting control subcircuit coupled to the first terminal of the driving transistor and configured to provide a signal at a power signal terminal to the first terminal of the driving transistor in response to a signal at a light emitting control terminal; a brightness control subcircuit coupled to the gate of the driving transistor and configured to provide a reference data signal at a reference data terminal to the gate of the driving transistor in response to a signal at a data strobe terminal; wherein the voltage of the reference data signal is the same as the data voltage so that the driving current generated by the driving transistor continues to be provided to the light emitting device, or the voltage of the reference data signal is less than a threshold voltage of the driving transistor so that the driving transistor stops providing the driving current to the light emitting device. The above-mentioned method of generating the driving current using the data voltage corresponding to the high grayscale improves the photoelectric conversion efficiency of each transistor and effectively improves the phenomenon of uneven brightness of the screen.

[0131] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program product systems. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product system implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0132] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program product systems according to the present application. It should be understood that each flow and / or box in the flow chart and / or block diagram, as well as the combination of the flow chart and / or box in the flow chart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one or more flow charts and / or one or more boxes in the block diagram.

[0133] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0134] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0135] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A pixel driving circuit, wherein: include: A driving transistor, a light emitting device, a light emitting control subcircuit, a signal writing subcircuit and a brightness control subcircuit; The signal writing subcircuit is coupled to the gate of the driving transistor and is configured to provide the data voltage and the signal Vref of the reference signal terminal to the gate of the driving transistor in a time-sharing manner, wherein the gray scale of the data voltage is a high gray scale; The second terminal of the driving transistor is coupled to the light emitting device and is configured to generate a driving current according to the data voltage; The light emitting control subcircuit is coupled to the first terminal of the driving transistor and is configured to provide a signal from the power signal terminal to the first terminal of the driving transistor in response to a signal from the light emitting control terminal; The brightness control subcircuit is coupled to the gate of the driving transistor and is configured to provide a reference data signal from a reference data terminal to the gate of the driving transistor in response to a signal from a data enable terminal, wherein a voltage of the reference data signal is the same as a data voltage so that the driving current generated by the driving transistor continues to be provided to the light-emitting device, or a voltage of the reference data signal is less than a threshold voltage of the driving transistor so that the driving transistor stops providing the driving current to the light-emitting device.

2. The pixel driving circuit according to claim 1, wherein: The brightness control subcircuit comprises: a first transistor; The control terminal of the first transistor is coupled to the data strobe terminal, the first terminal of the first transistor is coupled to the reference data terminal, and the second terminal of the first transistor is coupled to the gate of the driving transistor.

3. The pixel driving circuit according to claim 1, wherein: The signal writing subcircuit comprises: a second transistor; The control terminal of the second transistor is coupled to the scan signal terminal, the first terminal of the second transistor is coupled to the data signal terminal, and the second terminal of the second transistor is coupled to the gate of the driving transistor.

4. The pixel driving circuit according to claim 1, wherein: The signal writing subcircuit comprises: a third transistor and a fourth transistor; The control terminal of the third transistor is coupled to the scan signal terminal, and the first terminal of the third transistor is coupled to the scan signal terminal. coupled to the data signal terminal, the second terminal of the third transistor is coupled to the gate of the driving transistor; The control terminal of the fourth transistor is coupled to the reset reference signal terminal, the first terminal of the fourth transistor is coupled to the reference signal terminal, and the second terminal of the fourth transistor is coupled to the gate of the driving transistor.

5. The pixel driving circuit according to claim 1, wherein: The light emitting control subcircuit comprises: a fifth transistor; The control end of the fifth transistor is coupled to the light emitting control end, the first end of the fifth transistor is coupled to the power signal end, and the second end of the fifth transistor is coupled to the first end of the driving transistor.

6. The pixel driving circuit according to any one of claims 1 to 5, wherein: Also includes: a first capacitor and a second capacitor; A first end of the first capacitor is coupled to the gate of the driving transistor, and a second end of the first capacitor is coupled to the anode of the light emitting device; A first terminal of the second capacitor is coupled to the power signal terminal, and a second terminal of the second capacitor is coupled to the anode of the light emitting device.

7. The pixel driving circuit according to any one of claims 1 to 5, wherein: Also included: a third capacitor; A first terminal of the third capacitor is coupled to the gate of the driving transistor, and a second terminal of the third capacitor is coupled to the anode of the light emitting device.

8. The pixel driving circuit according to claim 1 or 2, wherein: Also includes a reset subcircuit; The reset subcircuit is coupled to the second end of the first capacitor, and is configured to provide a signal from an initialization signal end to the second end of the first capacitor in response to a signal from a reset signal end.

9. The pixel driving circuit according to claim 8, wherein: The reset subcircuit comprises: a sixth transistor; The control terminal of the sixth transistor is coupled to the reset signal terminal, the first terminal of the sixth transistor is coupled to the anode of the light emitting device, and the second terminal of the sixth transistor is coupled to the initialization signal terminal.

10. A display panel, wherein: The method comprises a pixel driving circuit as described in any one of claims 1 to 9.

11. A light emission control method, wherein: include: The signal writing subcircuit is coupled to the gate of the driving transistor and is configured to provide the data voltage and the signal of the reference signal terminal to the gate of the driving transistor in a time-sharing manner, wherein the gray scale of the data voltage is a high gray scale; The second terminal of the driving transistor is coupled to the light emitting device and is configured to generate a driving current according to the data voltage; The light emitting control subcircuit is coupled to the first terminal of the driving transistor and is configured to provide a signal from the power signal terminal to the first terminal of the driving transistor in response to a signal from the light emitting control terminal; The brightness control subcircuit is coupled to the gate of the driving transistor and is configured to provide a reference data signal from a reference data terminal to the gate of the driving transistor in response to a signal from a data enable terminal, wherein a voltage of the reference data signal is the same as a data voltage so that the driving current generated by the driving transistor continues to be provided to the light-emitting device, or a voltage of the reference data signal is less than a threshold voltage of the driving transistor so that the driving transistor stops providing the driving current to the light-emitting device.

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