Display device, display panel and driving method thereof, and pixel circuit detection method

Abstract

This disclosure relates to a display device, a display panel, a driving method thereof, and a detection method for pixel circuits, and pertains to the field of display technology. The display panel of this disclosure includes pixel units and a detection device. The pixel unit includes a pixel circuit and a light-emitting device. The pixel circuit includes a first transistor, a second transistor, a driving transistor, and a storage capacitor. The detection device is configured to: during a first time period in a first state of the pixel unit, turn off the first and second transistors and detect the leakage current of the driving transistor through a sensing line to obtain a first leakage current parameter; during a second time period after the first time period in the first state, detect a first characteristic parameter of the driving transistor to obtain a first reference characteristic parameter; and determine a first target characteristic parameter based on the first leakage current parameter and the first reference characteristic parameter.

Description

Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular, to a display device, a display panel, a driving method of a display panel, and a detection method of a pixel circuit. Background Art

[0002] The pixel units in the display panel generally include a light emitting device and a pixel circuit connected to each other. The pixel circuit can output a driving current to the light emitting device to drive the light emitting device to emit light. Due to the influence of factors such as the threshold voltage drift of the transistor in the pixel circuit, the driving current output by the pixel circuit to the light emitting device is prone to abnormality.

[0003] In the related art, internal compensation or external compensation is usually used to compensate the pixel circuit to solve the problem of abnormal driving current output to the light-emitting device caused by threshold voltage drift. However, the data sampling accuracy is low during the external compensation process, which affects the compensation effect.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field.

[0005] Public Content

[0006] The purpose of the present disclosure is to overcome the above-mentioned deficiencies of the prior art and to provide a display device, a display panel, a driving method of a display panel and a detection method of a pixel circuit.

[0007] According to one aspect of the present disclosure, there is provided a display panel, comprising:

[0008] A plurality of pixel units, each of which comprises a pixel circuit and a light-emitting device connected to each other, wherein the pixel circuit comprises:

[0009] a first transistor, wherein a first electrode of the first transistor is connected to a data line;

[0010] A driving transistor, wherein a control terminal of the driving transistor is connected to a second electrode of the first transistor, and a first electrode of the driving transistor is connected to a first power supply terminal;

[0011] a second transistor, wherein a first electrode of the second transistor is connected to a second electrode of the driving transistor, and a second electrode of the second transistor is connected to a sensing line;

[0012] A storage capacitor connected between the control terminal of the driving transistor and the light emitting device;

[0013] A detection device, the detection device is used for:

[0014] In a first time period in a first state of the pixel unit, the first transistor and the second transistor are turned off, and a leakage amount of the driving transistor through the sensing line is detected to obtain a first leakage parameter;

[0015] In a second time period after the first time period in the first state, detecting a first characteristic parameter of the driving transistor to obtain a first reference characteristic parameter;

[0016] A first target characteristic parameter is determined according to the first leakage parameter and the first reference characteristic parameter.

[0017] In an exemplary embodiment of the present disclosure, the leakage amount of the driving transistor through the sensing line is detected to obtain a first leakage parameter; comprising:

[0018] At an initial moment of the first period, inputting a first reference voltage to the sensing line;

[0019] At the end of the second period, detecting the voltage of the sensing line to obtain a first target voltage;

[0020] A first leakage parameter is determined according to the first target voltage and the first reference voltage.

[0021] In an exemplary embodiment of the present disclosure, the detection device is also used for:

[0022] In a first reset period between the first period and the second period, a voltage of the sensing line is reset.

[0023] In an exemplary embodiment of the present disclosure, the first time period and the second time period are of the same length.

[0024] In an exemplary embodiment of the present disclosure, the first characteristic parameter is a threshold voltage; and the first state is a non-display state.

[0025] In an exemplary embodiment of the present disclosure, detecting a first characteristic parameter of the driving transistor to obtain a first reference characteristic parameter comprises:

[0026] Turning on the first transistor and the second transistor, writing a first reference voltage to the control terminal of the driving transistor, and writing a first starting voltage to the second terminal of the driving transistor, so that the driving transistor is turned on;

[0027] A current is input to the first electrode of the driving transistor, and a voltage at the second electrode of the driving transistor when the driving transistor is turned off is detected as a first reference characteristic parameter.

[0028] In an exemplary embodiment of the present disclosure, the detection device is also used for:

[0029] In a third time period in the second state of the pixel unit, the first transistor and the second transistor are turned off, and the leakage amount of the driving transistor through the sensing line is detected to obtain a second leakage parameter;

[0030] In a fourth time period after the third time period in the second state, detecting a second characteristic parameter of the driving transistor to obtain a second reference characteristic parameter;

[0031] A second target characteristic parameter is determined according to the second leakage parameter and the second reference characteristic parameter.

[0032] In an exemplary embodiment of the present disclosure, the leakage amount of the driving transistor through the sensing line is detected to obtain a second leakage parameter; comprising:

[0033] At an initial moment of the third period, inputting a second reference voltage to the sensing line;

[0034] At the end of the third period, detecting the voltage of the sensing line to obtain a second target voltage;

[0035] A second leakage parameter is determined according to the second target voltage and the second reference voltage.

[0036] In an exemplary embodiment of the present disclosure, the detection device is also used for:

[0037] The sensing line is reset in a second reset period between the third period and the fourth period.

[0038] In an exemplary embodiment of the present disclosure, the third time period and the fourth time period are of the same duration.

[0039] In an exemplary embodiment of the present disclosure, the second characteristic parameter is mobility; the second state is a display state;

[0040] The third period, the second reset period and the fourth period are in a blanking phase.

[0041] In an exemplary embodiment of the present disclosure, detecting the second characteristic parameter of the driving transistor to obtain the second reference characteristic parameter comprises:

[0042] In the reset phase, the first transistor and the second transistor are turned on, a second reference voltage is input to the control terminal of the driving transistor, the second reference voltage is equal to the sum of the base voltage and the first characteristic parameter; and a reset voltage is input to the sensing line;

[0043] In the charging stage, the second transistor is turned on, and the driving transistor inputs a driving current to the sensing line under the action of the detection voltage, so that the voltage of the sensing line gradually increases;

[0044] In the detection phase, the voltage on the sensing line is detected to obtain a detection voltage;

[0045] In the processing stage, a second reference characteristic parameter of the driving transistor is determined according to the second reference voltage and the detection voltage.

[0046] According to one aspect of the present disclosure, a detection method for a pixel circuit is provided, wherein the pixel circuit includes a first transistor, a second transistor, a driving transistor and a storage capacitor, wherein a first electrode of the first transistor is connected to a data line; a control terminal of the driving transistor is connected to a second electrode of the first transistor, and a first electrode of the driving transistor is connected to a first power supply terminal; a first electrode of the second transistor is connected to a second electrode of the driving transistor, and a second electrode of the second transistor is connected to a sensing line; and the storage capacitor is connected between the control terminal of the driving transistor and a light-emitting device;

[0047] The detection method comprises:

[0048] In a first time period in a first state of the pixel unit, the first transistor and the second transistor are turned off, and a leakage amount of the driving transistor through the sensing line is detected to obtain a first leakage parameter;

[0049] In a second time period after the first time period in the first state, detecting a first characteristic parameter of the driving transistor to obtain a first reference characteristic parameter;

[0050] A first target characteristic parameter is determined according to the first leakage parameter and the first reference characteristic parameter.

[0051] In an exemplary embodiment of the present disclosure, the leakage amount of the driving transistor through the sensing line is detected to obtain a first leakage parameter; comprising:

[0052] At an initial moment of the first period, inputting a first reference voltage to the sensing line;

[0053] At the end of the second period, detecting the voltage of the sensing line to obtain a first target voltage;

[0054] A first leakage parameter is determined according to the first target voltage and the first reference voltage.

[0055] In an exemplary embodiment of the present disclosure, the first characteristic parameter is a threshold voltage; and the first state is a non-display state.

[0056] In an exemplary embodiment of the present disclosure, the detection device is also used for:

[0057] In a third time period in the second state of the pixel unit, the first transistor and the second transistor are turned off, and the leakage amount of the driving transistor through the sensing line is detected to obtain a second leakage parameter;

[0058] In a fourth time period after the third time period in the second state, detecting a second characteristic parameter of the driving transistor to obtain a second reference characteristic parameter;

[0059] A second target characteristic parameter is determined according to the second leakage parameter and the second reference characteristic parameter.

[0060] In an exemplary embodiment of the present disclosure, the leakage amount of the driving transistor through the sensing line is detected to obtain a second leakage parameter; comprising:

[0061] At an initial moment of the third period, inputting a second reference voltage to the sensing line;

[0062] At the end of the third period, detecting the voltage of the sensing line to obtain a second target voltage;

[0063] A second leakage parameter is determined according to the second target voltage and the second reference voltage.

[0064] In an exemplary embodiment of the present disclosure, the second characteristic parameter is mobility; the second state is a display state;

[0065] The third period, the second reset period and the fourth period are in a blanking phase.

[0066] According to one aspect of the present disclosure, a method for driving a display panel is provided, wherein the display panel includes a plurality of pixel units, each of the pixel units includes a pixel circuit and a light-emitting device connected to each other; the driving method includes:

[0067] Detecting a first target characteristic parameter of each of the driving transistors in the pixel circuit using any of the detection methods described above;

[0068] In the display state of the display panel, the data signal of the pixel circuit where the driving transistor is located is compensated according to the first target characteristic parameter of the driving transistor.

[0069] According to one aspect of the present disclosure, a display device is provided, comprising any one of the display panels described above.

[0070] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0072] Figure 1 Schematic diagram of a pixel circuit in the related art.

[0073] Figure 2 This is a schematic diagram of leakage when detecting threshold voltage in the related art.

[0074] Figure 3 This is a simulation result diagram of leakage when detecting threshold voltage in the related art.

[0075] Figure 4 This is a schematic diagram of leakage current when detecting mobility in the related art.

[0076] Figure 5 and Figure 6 This is a simulation result diagram of leakage when detecting mobility in the related art.

[0077] Figure 7 It is a schematic diagram of an embodiment of a display panel disclosed in the present invention.

[0078] Figure 8 FIG. 4 is a schematic diagram of a pixel circuit in an embodiment of a display panel disclosed herein.

[0079] Fig. 9 The timing of the detection method in an embodiment of the display panel disclosed in the present invention is Figure 1 .

[0080] Fig.10 The timing of the detection method in an embodiment of the display panel disclosed in the present invention is Figure 2 . DETAILED DESCRIPTION

[0081] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted. In addition, the drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale.

[0082] The terms "a", "an", "the", "said" and "at least one" are used to indicate the presence of one or more elements / components / etc.; the terms "including" and "having" are used to express an open-ended inclusive meaning and mean that additional elements / components / etc. may exist in addition to the listed elements / components / etc.; the terms "first", "second", etc. are used merely as labels and are not intended to limit the quantity of their objects.

[0083] The transistor of the embodiment of the present disclosure refers to an element including at least three terminals: a gate, a drain, and a source. The transistor has a channel region between the drain (drain terminal, drain region, or drain electrode) and the source (source terminal, source region, or source), and the current can flow through the drain, the channel region, and the source. The channel region refers to the region where the current mainly flows. At the same time, the gate can be a control terminal, the drain can be a first pole, the source can be a second pole, or the first pole can be a source and the second pole can be a drain. In the case of using transistors with opposite polarities or the case of a change in the direction of current during circuit operation, the functions of the "source" and the "drain" are sometimes interchanged. Therefore, in this specification, the "source" and the "drain" can be interchanged.

[0084] The transistors used in the embodiments of the present disclosure may include any one of a P-type transistor and an N-type transistor, wherein the P-type transistor is turned on when the gate is at a low level and is turned off when the gate is at a high level, and the N-type transistor is turned on when the gate is at a high level and is turned off when the gate is at a low level.

[0085] In the related art, for an OLED (Organic Light-Emitting Diode) display panel, it may include a plurality of pixel units, each of which includes a pixel circuit and a light-emitting device, and the pixel circuit may be compensated by external compensation to improve the display effect. Specifically, for a pixel circuit, it is usually necessary to compensate the output characteristics of the driving transistor by sensing the threshold voltage and mobility of the driving transistor to solve problems such as uneven brightness and improve the display effect. When sensing the mobility, it is necessary to sense the voltage of the sensing line connected to the driving transistor in order to detect the threshold voltage and mobility of the driving transistor.

[0086] Take a pixel circuit of a pixel unit in the related art as an example. Figure 1 As shown, the pixel circuit includes a first transistor T1, a second transistor T2, a driving transistor Dr, and a storage capacitor Cst.

[0087] The first electrode of the first transistor T1 is connected to the data line Data, and the second electrode is connected to the gate of the driving transistor Dr. The first electrode of the driving transistor Dr is connected to the first power supply terminal VDD, and the second electrode is connected to an electrode of a light-emitting device OLED, and the other electrode of the light-emitting device OLED is connected to the second power supply terminal VSS. The first electrode of the second transistor T2 is connected to the second electrode of the driving transistor Dr, and the second electrode is connected to the sensing line Sense. The storage capacitor Cst is connected between the gate and the second electrode of the driving transistor Dr.

[0088] The sensing line Sense is connected to an analog-to-digital converter ADC through a first switch unit S1, and the sensing line Sense is also connected to a digital-to-analog converter DAC through a second switch unit S2. The first switch unit S1 can be turned on or off by a sampling signal, and the second switch unit S2 can be turned on or off by a switch signal. Both the first switch unit S1 and the second switch unit S2 are turned on in a high level state.

[0089] like Figure 2 and Figure 4 As shown, the display panel has a plurality of pixel units P arranged in an array along the row direction and the column direction. Figure 2 and Figure 4 In the figure, P(n, m) is used to represent the nth row, the mth pixel unit P, and n and m are both positive integers. The sensing line Sense can extend along the column direction, and the pixel circuits of any column of pixel units P are connected to the same sensing line Sense, and the same sensing line Sense can be connected to multiple columns of pixel circuits. The row direction and the column direction only refer to two directions perpendicular to each other, and do not limit their actual directions. It can be known to those skilled in the art that if the display panel is rotated, the actual directions of the row direction and the column direction will also change.

[0090] For the driving transistor, due to the unavoidable leakage phenomenon, especially for the LTPS (Low Temperature Poly-Silicon) transistor, the leakage current is large, so it can leak through the sensing line Sense, and the detection results of the threshold voltage and mobility are based on the voltage on the sensing line Sense. Therefore, the leakage of the driving transistor will affect the accuracy of the detection results of the threshold voltage and mobility, thereby affecting the final compensation effect. For example:

[0091] When the threshold voltage of a driving transistor is detected, the light emitting device can be turned off. Figure 2 As shown, all pixel units P connected to the sensing line Sense are non-luminous. When a threshold voltage of a certain pixel unit P is detected, the pixel unit P charges the sensing line Sense, and the sensing line Sense leaks to the remaining pixel units P due to the leakage of the driving transistor Dr. Figure 3 As shown, Figure 3 Curve I in the figure shows the detection result of the threshold voltage of the driving transistor when the sensing line Sense is connected to only one pixel circuit; Curve II shows the detection structure of the threshold voltage of the driving transistor when one sensing line Sense is connected to 2880 rows of pixel circuits; by comparison, it can be seen that due to the leakage factor, the detection result shown by Curve II cannot reach the detection result of Curve I, and finally stays at 1.834V. This makes the accuracy of the detection result low, affecting the compensation effect.

[0092] like Figure 4 As shown, Figure 4 The figure shows the state of leakage when detecting mobility. A sensing line Sense can be connected to four columns of pixel circuits. When the mobility of pixel unit P (3, 2) is detected, except for pixel unit P (3, n) which does not emit light, the other pixel units P are in the light-emitting state. At this time, the pixel unit P that is in the state of emitting light will leak to the sensing line Sense, and the sensing line Sense will leak to the pixel unit that does not emit light.

[0093] like Figure 5 and Figure 6 As shown, Figure 5 and Figure 6 In FIG. , a sensing line Sense is connected to 2880 rows of pixel circuits. Figure 5 In the example, all pixel units P connected to a sensing line Sense are in a closed state (not emitting light), and the sensing line Sense is set to a voltage of 2V. After 60μs, the voltage change ΔVA is 6mV. Figure 6 In the example, all pixel units P connected to a sensing line Sense are in the on state (emitting light), and the sensing line Sense is set to 0V. After 60μs, its voltage change ΔVB is 19.77mV. It can be seen that the leakage of the driving transistor Dr will affect the accuracy of the mobility detection result, thereby affecting the compensation effect.

[0094] Based on the above technical problems, the present disclosure provides a display panel such as Figure 7 and Figure 8 As shown, the display panel includes a pixel unit P and a detection device 1, wherein:

[0095] There are multiple pixel units P, which are arrayed in row and column directions. Each pixel unit P may include a pixel circuit and a light-emitting device OLED connected to each other. The pixel circuit is used to drive the light-emitting device OLED to emit light. The structure of the light-emitting device OLED is not specifically limited here.

[0096] Each pixel circuit may include a first transistor T1, a driving transistor Dr, a second transistor T2 and a storage capacitor Cst, wherein:

[0097] The first electrode of the first transistor T1 is connected to the data line Data; the control end of the driving transistor Dr is connected to the second electrode of the first transistor T1, and the first electrode of the driving transistor Dr is connected to the first power supply terminal VDD. The first electrode of the second transistor T2 is connected to the second electrode of the driving transistor Dr, and the second electrode of the second transistor T2 is connected to the sensing line Sense; the first electrode plate of the storage capacitor Cst is connected to the control end of the driving transistor Dr, the second electrode plate is connected to the second electrode of the driving transistor Dr and an electrode of the light-emitting device OLED, and the other electrode of the light-emitting device OLED is connected to the second power supply terminal VSS. The control end of the first transistor T1 is connected to the first control signal terminal G1, and the control end of the second transistor T2 is connected to the second control signal terminal G2.

[0098] The sensing line Sense can be connected to an analog-to-digital converter ADC through a first switch unit S1, and the sensing line Sense is also connected to a digital-to-analog converter DAC through a second switch unit S2. The first switch unit S1 can be controlled to be turned on or off by a sampling signal Sam, and the second switch unit S2 can be controlled to be turned on or off by a switch signal. The first switch unit S1 and the second switch unit S2 are both turned on in a high level state. The first switch unit S1 and the second switch unit S2 can both be transistors or other switching devices or switching circuits, and their structures are not specifically limited here.

[0099] The pixel circuits of the same column of pixel units P can be connected to the same sensing line Sense, and the number of pixel units P in a column of pixel units P is not particularly limited. At the same time, the same sensing line Sense can be connected to the pixel circuits of one or more columns of pixel units P. For example, the same sensing line Sense can be connected to the pixel circuits of four columns of pixel units P.

[0100] The detection device 1 can be used to perform the following steps S110 to S130, wherein:

[0101] Step S110 , in a first time period t1 in a first state of the pixel unit, the first transistor T1 and the second transistor T2 are turned off, and the leakage amount of the driving transistor Dr through the sensing line Sense is detected to obtain a first leakage parameter.

[0102] Step S120 , in a second time period t2 after the first time period t1 in the first state, detecting a first characteristic parameter of the driving transistor Dr to obtain a first reference characteristic parameter.

[0103] Step S130: determining a first target characteristic parameter according to the first leakage parameter and the first reference characteristic parameter.

[0104] The display panel of the embodiment of the present disclosure can detect the leakage of the driving transistor Dr through the sensing line Sense before detecting the first target characteristic parameter, that is, obtain the first leakage parameter, and then determine the first target characteristic parameter according to the first leakage parameter and the first reference characteristic parameter, that is, compensate the first reference characteristic parameter by the first leakage parameter, so as to obtain the first target characteristic parameter, so that the detection result of the first characteristic parameter is more accurate, which is conducive to improving the accuracy of external compensation, thereby improving the display effect. The first target characteristic parameter can be a threshold voltage or mobility.

[0105] The following is an exemplary description of the process of detecting the first target characteristic parameter:

[0106] like Figure 7 and Figure 8 As shown, in Figure 8 In the figure, G1 represents the timing of the first control signal terminal G1, G2 represents the timing of the second control signal terminal G2, Data represents the timing of the data line Data, Sense represents the timing on the sensing line Sense, and Sam represents the timing of the control terminal of the first switch unit S1.

[0107] like Figure 7 and Figure 8 As shown, in step S110, in the first time period t1 in the first state of the pixel unit P, the first transistor T1 and the second transistor T2 are turned off, and the leakage amount of the driving transistor Dr through the sensing line Sense is detected to obtain a first leakage parameter.

[0108] The first transistor T1, the second transistor T2, and the driving transistor Dr can all be N-type LTPS transistors. The first characteristic parameter of the driving transistor Dr can be its threshold voltage.

[0109] The first state is the state of the pixel unit, which can be a non-display state, that is, the state of each pixel unit when the display panel is in the shutdown state. In the first state, each pixel unit P does not emit light, that is, the data signal for controlling the light-emitting device OLED to emit light is not input to the data line Data. However, it should be noted that the first state is not a power-off state, but the light-emitting device OLED is turned off. The data line Data, the first power supply terminal VDD and the sensing line Sense can all input other electrical signals as long as the light-emitting device OLED is not driven to emit light. The shutdown state of the display panel can be used to detect the threshold voltage (first characteristic parameter) to avoid additional time for detection. Of course, in other embodiments of the present disclosure, the first state can also be a display state, and the threshold voltage can be detected in the blanking stage of each frame to avoid affecting the display state.

[0110] The first time period t1 may be any time period in the first state, and in the first time period t1, the first transistor T1 and the second transistor T2 may be turned off. At the same time, a certain voltage may be set to the sensing line Sense, and after a certain period of time, the voltage change of the sensing line Sense may be detected, thereby determining the influence of the leakage of the driving transistor Dr on the voltage. For a display panel, the threshold voltage of the driving transistor Dr may be detected after each shutdown and before the next startup.

[0111] like Figure 7 and Figure 8 As shown, specifically: the leakage amount of the driving transistor Dr through the sensing line Sense is detected to obtain a first leakage parameter; that is, step S110 may include steps S1110 to S1130, wherein:

[0112] Step S1110 , at the initial moment of the first period t1 , setting a first reference voltage to the sensing line Sense.

[0113] The magnitude of the first reference voltage is not particularly limited, for example, it may be 2 V. At the initial moment of the first period t1, the second switch unit S2 may be turned on, the first reference voltage may be input to the sensing line Sense through the detection device 1, and the first switch unit S1 may be turned off.

[0114] Step S1120 : At the end of the first period t1 , the voltage of the sensing line Sense is detected to obtain a first target voltage.

[0115] The duration of the first period t1 is not specifically limited here. After the first period t1, the first reference voltage initially set will decrease due to leakage. Therefore, the first switch unit S1 can be turned on, the second switch unit S2 can be turned off, and the voltage of the sensing line Sense is detected to obtain the first target voltage. Due to the leakage phenomenon, the first target voltage is lower than the first reference voltage.

[0116] Step S1130: determining a first leakage parameter according to a deviation between the first target voltage and the first reference voltage.

[0117] The first leakage parameter may be the difference between the first reference voltage and the first target voltage. The first leakage parameter may reflect the influence of the leakage of the driving transistor Dr on the voltage of the sensing line Sense, so that the detection result of the threshold voltage may be corrected by the first leakage parameter to improve the accuracy of the detected threshold voltage.

[0118] The calculation formula of the first leakage parameter is as follows:

[0119] ΔV1=Vs1-Vt1;

[0120] ΔV1 is a first leakage parameter, Vs1 is a first reference voltage, and Vt1 is a first target voltage.

[0121] In step S120 , in a second time period t2 after the first time period t1 in the first state of the pixel unit, the first characteristic parameter of the driving transistor Dr is detected to obtain a first reference characteristic parameter.

[0122] The second period t2 is located after the first period t1, and the duration of the second period t2 is not particularly limited herein. In the second period t2, the threshold voltage of the driving transistor Dr can be detected to obtain a reference value of the threshold voltage, ie, a first reference characteristic parameter.

[0123] For example, step S120 may include step S1210 and step S1220, wherein:

[0124] Step S1210 , turn on the first transistor T1 and the second transistor T2 , write a first reference voltage to the control terminal of the driving transistor Dr, and write a first starting voltage to the second terminal of the driving transistor Dr, so as to turn on the driving transistor Dr.

[0125] The first reference voltage is greater than the first starting voltage, and the gate-source voltage difference Vgs of the driving transistor Dr may be equal to the difference between the first reference voltage and the first starting voltage. If Vgs is greater than the threshold voltage, the driving transistor Dr may be turned on.

[0126] Step S1220: input current to the first electrode of the driving transistor Dr, and detect the voltage of the second electrode of the driving transistor Dr when the driving transistor Dr is turned off as a first reference characteristic parameter.

[0127] After the driving transistor Dr is turned on, the first power supply terminal VDD inputs current to the first electrode of the driving transistor Dr, so that the voltage of the second electrode of the driving transistor Dr gradually increases. In this process, the first switch unit S1 can be turned on, and the detection device 1 can detect the voltage of the second electrode of the driving transistor Dr through the sensing line Sense. When the driving transistor Dr is turned off, it means that the difference between the first reference voltage and the first starting voltage reaches the critical value of turning on the driving transistor D, that is, the threshold voltage. When the magnitudes of the first reference voltage and the first starting voltage are known, the reference value of the threshold voltage, that is, the first reference characteristic parameter, can be calculated.

[0128] like Figure 7 and Figure 8 As shown, in step S130, a first target characteristic parameter is determined according to the first leakage parameter and the first reference characteristic parameter.

[0129] Since the first leakage parameter can be used to reflect the influence of the leakage of the driving transistor Dr on the voltage of the sensing line Sense, the first leakage parameter can be used to compensate the first reference characteristic parameter to obtain the first target characteristic parameter, that is, the first target characteristic parameter Vth=Vths+ΔV1, where Vths is the first reference characteristic parameter.

[0130] Furthermore, in some embodiments of the present disclosure, the detection device 1 is further used to: reset the voltage of the sensing line Sense in the first reset period t5 between the first period t1 and the second period t2, for example, to make the voltage of the sensing line Sense zero.

[0131] In addition, in order to further improve the accuracy of the detection results, the duration of the first time period t1 and the second time period t2 can be made the same, that is, the duration of detecting the first leakage parameter is the same as the duration of detecting the first reference characteristic parameter, so that the first leakage parameter can reflect the leakage situation during the detection of the first reference characteristic.

[0132] On the basis of detecting the first characteristic parameter (threshold voltage) as described above, the detection device 1 can also be used to detect the second characteristic parameter, so as to determine the compensation of the data signal for driving the pixel unit P to emit light according to the first characteristic parameter and the second specific parameter. On the basis of the first characteristic parameter being the threshold voltage, the second characteristic parameter can be the mobility. Figure 7 and Fig. 9 As shown, in some embodiments of the present disclosure, the detection device 1 is further used to perform the following steps S210 to S230 to detect the mobility of the driving transistor Dr, wherein:

[0133] Step S210, in a third time period t3 in the second state of the pixel unit, turning off the first transistor T1 and the second transistor T2, and detecting the leakage amount of the driving transistor Dr through the sensing line Sense to obtain a second leakage parameter;

[0134] Step S220, in a fourth time period t4 after the third time period t3 in the second state, detecting a second characteristic parameter of the driving transistor Dr to obtain a second reference characteristic parameter;

[0135] Step S230: determining a second target characteristic parameter according to the second leakage parameter and the second reference characteristic parameter.

[0136] like Figure 7 and Fig. 9 As shown, Fig. 9 In the figure, G1 represents the timing of the first control signal terminal G1, G2 represents the timing of the second control signal terminal G2, Data represents the timing of the data line Data, Sense represents the timing on the sensing line Sense, and Sam represents the timing of the control terminal of the first switch unit S1.

[0137] The following is an exemplary description of the process of detecting the second target characteristic parameter:

[0138] In step S210 , in a third period t3 in the second state of the pixel unit, the first transistor T1 and the second transistor T2 are turned off, and the leakage amount of the driving transistor Dr through the sensing line Sense is detected to obtain a second leakage parameter.

[0139] The second state is the state of the pixel unit P, which may be a display state, that is, the state of each pixel unit P when the display panel is in the power-on state. The mobility (second characteristic parameter) may be detected during the blanking phase of each frame to avoid additional time for detection. Of course, in other embodiments of the present disclosure, the second state may also be a non-display state, and the threshold voltage may be detected in the power-off state to avoid affecting the display state.

[0140] The third time period t3 may be any time period in the first state, and in the third time period t3, both the first transistor T1 and the second transistor T2 may be turned off. At the same time, the influence of the leakage of the driving transistor Dr on the voltage may be determined by setting a voltage to the sensing line Sense and detecting the voltage change of the sensing line Sense after a certain period of time. Specifically: the leakage amount of the driving transistor Dr through the sensing line Sense is detected to obtain the second leakage parameter; that is, step S210 may include steps S2110-step S2130, wherein:

[0141] Step S2110: at the initial moment of the third time period t3, the sensing line Sense is set to a second reference voltage.

[0142] The magnitude of the second reference voltage is not particularly limited, for example, it may be 1 V. At the beginning of the first period t1, the second switch unit S2 may be turned on, the first reference voltage may be input to the sensing line Sense through the detection device 1, and the first switch unit S1 may be turned off.

[0143] Step S2120: At the end of the third period t3, the voltage of the sensing line Sense is detected to obtain a second target voltage.

[0144] The duration of the third time period t3 is not specifically limited here. After the third time period t3, the voltage set at the initial moment will be reduced due to leakage. Therefore, the first switch unit S1 can be turned on, the second switch unit S2 can be turned off, and the voltage of the sensing line Sense is detected to obtain the second target voltage. Due to the existence of leakage, the second target voltage is less than or greater than the second reference voltage. Specifically, if the second leakage parameter of the pixel circuit of the luminous pixel unit is detected, it may leak to other pixel units through the sensing line Sense, so the second target voltage is less than the second reference voltage; if the second leakage parameter of the pixel circuit of the luminous pixel unit is detected, the pixel circuit may receive the leakage of other luminous pixel units, so that the second target voltage is higher than the second reference voltage.

[0145] Step S2130: determining a second leakage parameter according to a deviation between the second target voltage and the second reference voltage.

[0146] The second leakage parameter can be the difference or sum between the second reference voltage and the second target voltage. The second leakage parameter can reflect the influence of the leakage of the driving transistor Dr on the voltage of the sensing line Sense, so that the detection result of the threshold voltage can be corrected by the second leakage parameter to improve the accuracy of the detected threshold voltage.

[0147] The calculation formula of the second leakage parameter is as follows:

[0148] ΔV2=Vs2-Vt2;

[0149] ΔV2 is the second leakage parameter, Vs2 is the second reference voltage, and Vt2 is the second target voltage.

[0150] In step S220 , in a fourth period t4 after the third period t3 in the second state, the second characteristic parameter of the driving transistor Dr is detected to obtain a second reference characteristic parameter.

[0151] The fourth period t4 is located after the third period t3, and the duration of the fourth period t4 is not particularly limited. In the fourth period t4, the mobility of the driving transistor Dr can be detected to obtain a reference value of the mobility, that is, a second reference characteristic parameter.

[0152] The second characteristic parameter of the driving transistor Dr is detected to obtain a second reference characteristic parameter; that is, step S220 may include:

[0153] In the reset phase, the first transistor T1 and the second transistor T2 are turned on, a second reference voltage is input to the control terminal of the driving transistor Dr, and the second reference voltage is equal to the sum of the basic voltage and the first characteristic parameter; a reset voltage is input to the sensing line Sense.

[0154] The magnitude of the basic voltage is not specifically limited here, and the first characteristic parameter is the threshold voltage of the driving transistor Dr detected in the last first state. The second reference voltage can be input to the control end of the driving transistor Dr through the data line Data to turn on the driving transistor Dr. The reset voltage is input to the sensing line Sense, so that the second poles of the driving transistors Dr in different pixel driving circuits can be reset to the same voltage value, thereby avoiding the influence of the second pole voltage of the driving transistor Dr on the voltage of the sensing line Sense during the reset stage.

[0155] In the charging stage, the first transistor T1 is turned off, the second transistor T2 is turned on, and the driving transistor Dr inputs a driving current to the sensing line Sense under the action of the second reference voltage, so that the voltage of the sensing line Sense gradually increases.

[0156] In the detection phase, the first switch unit 1 and the second switch unit 2 are turned off, and the voltage on the sensing line Sense is detected to obtain a detection voltage.

[0157] The second reference voltage and the reset voltage can keep the gate-source voltage difference of the driving transistor Dr unchanged, thereby outputting a stable current. According to the formula I = K (Vgs-Vth) 2 =CV / t, the mobility K of the driving transistor Dr can be calculated. Where:

[0158] Vgs is the gate-source voltage difference of the driving transistor Dr, Vgs=Vd+Vth-Vf; Vd is the basic voltage; Vth is the first target characteristic parameter, that is, the threshold voltage of the driving transistor Dr; Vf is the reset voltage.

[0159] C represents the capacitance value of the sensing line Sense itself, V represents the sensing line voltage value detected in the detection phase, that is, the detection voltage; t represents the duration of the charging phase.

[0160] In the calculation stage, a second reference characteristic parameter of the driving transistor Dr is determined according to the second reference voltage and the detection voltage.

[0161] A reference value of the mobility, ie, a second reference characteristic parameter, can be determined according to the detection voltage.

[0162] In step S230, a second target characteristic parameter is determined according to the second leakage parameter and the second reference characteristic parameter.

[0163] Since the second leakage parameter can be used to reflect the influence of the leakage of the driving transistor Dr on the voltage of the sensing line Sense, the first reference characteristic parameter can be compensated by the second leakage parameter to obtain the second target characteristic parameter, that is, the second target characteristic parameter K=Ks+ΔV2, where Ks is the first reference characteristic parameter. It should be noted that ΔV2 can be a positive value or a negative value, that is, the second reference voltage can be less than or greater than the second target voltage.

[0164] Furthermore, in some embodiments of the present disclosure, the detection device 1 is also used to: reset the voltage of the sensing line Sense in a second reset period t6 between the third period t3 and the fourth period t4, for example, to make the voltage of the sensing line Sense zero.

[0165] In addition, in order to further improve the accuracy of the detection result, the duration of the third period t3 and the fourth period t4 can be made the same, that is, the duration of detecting the second leakage parameter is the same as the duration of detecting the second reference characteristic parameter, so that the second leakage parameter can reflect the leakage situation in the process of detecting the second reference characteristic. The third period t3, the second reset period and the fourth period t4 are in the blanking stage.

[0166] Furthermore, since the mobility detection is performed in the blanking phase, in order to avoid affecting the image display, after the fourth period t4, that is, after the mobility detection is completed, data write-back can be performed, and the specific principle of the data write-back operation is not described in detail here. The data write-back operation is performed in the data write-back phase t7.

[0167] In some embodiments of the present disclosure, Figure 7 As shown, the detection device 1 may include: a source driving circuit 11, a timing controller 12, and a processor (not shown in the figure). The source driving circuit 11 may be connected to the pixel circuit through the data line Data; the timing controller 12 is connected to the source driving circuit 11, and is used to control the source driving circuit 11 to input a first reference voltage and a second reference voltage to the data line Data, and the processor is used to determine the threshold voltage and mobility of the driving transistor Dr according to the detected voltage of the sensing line Sense.

[0168] The source driving circuit 11 in the detection device 1 can share the source driving circuit in the display panel for providing data signals, the timing controller 12 can share the timing controller in the display panel for providing timing control signals, and the processor can be integrated into the main circuit board in the display panel. Figure 7 As shown, the detection device can also share the gate drive circuit 13 in the display panel to provide a gate drive signal to the first switch unit S1 and the second switch unit S2. The detection device 1 can also include a voltage sensing unit 14, which is used to sense the voltage on the sensing line Sense. The voltage sensing unit 14 can also be integrated into the source drive circuit 11.

[0169] The present disclosure provides a method for detecting a pixel circuit, the structure of which can refer to the pixel circuit in the embodiment of the display panel. The detection method includes:

[0170] In a first time period in a first state of the pixel unit, the first transistor and the second transistor are turned off, and a leakage amount of the driving transistor through the sensing line is detected to obtain a first leakage parameter;

[0171] In a second time period after the first time period in the first state, detecting a first characteristic parameter of the driving transistor to obtain a first reference characteristic parameter;

[0172] A first target characteristic parameter is determined according to the first leakage parameter and the first reference characteristic parameter.

[0173] The details of each step of the detection method of the pixel circuit disclosed in the present invention have been described in the above embodiment of the display panel and will not be described in detail here.

[0174] The embodiment of the present disclosure provides a method for driving a display panel, wherein the display panel includes a plurality of pixel units, each pixel unit includes a pixel circuit and a light-emitting device connected to each other, and the structure of the display panel can refer to the embodiment of the display panel above. The driving method includes:

[0175] Detecting a first target characteristic parameter of each driving transistor in the pixel circuit using the detection method of any of the above embodiments;

[0176] In the driving stage of the display panel, the data signal of the pixel circuit where the driving transistor is located is compensated according to the first target characteristic parameter of the driving transistor.

[0177] Furthermore, the detection method of any of the above embodiments can be used to detect the second target characteristic parameter of each driving transistor in the pixel circuit, and the data signal of the pixel circuit where the driving transistor is located can be compensated according to the first target characteristic parameter and the second target characteristic parameter of the driving transistor, thereby controlling the pixel unit to emit light.

[0178] The present disclosure also provides a display device, including a display panel of any of the above embodiments, and its structure, driving method and beneficial effects can be referred to in the above embodiments, which will not be described in detail here. The display device can be an electronic device with image display function such as a mobile phone, a television, or a tablet computer.

[0179] It should be noted that, although the steps of the method in the present disclosure are described in a specific order in the drawings, this does not require or imply that the steps must be performed in this specific order, or that all the steps shown must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps, etc.

[0180] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. A display panel, wherein: include: A plurality of pixel units, each of the pixel units comprises a pixel circuit and a light-emitting device connected to each other, the pixel circuit comprising: a first transistor, wherein a first electrode of the first transistor is connected to a data line; A driving transistor, wherein a control terminal of the driving transistor is connected to the second electrode of the first transistor, and a first electrode of the driving transistor is connected to a first power supply terminal; a second transistor, wherein a first electrode of the second transistor is connected to a second electrode of the driving transistor, and a second electrode of the second transistor is connected to a sensing line; the sensing line is different from the data line; A storage capacitor connected between the control terminal of the driving transistor and the light emitting device; A detection device, the detection device is used for: In a first time period in a first state of the pixel unit, the first transistor and the second transistor are turned off, and a leakage amount of the driving transistor through the sensing line is detected to obtain a first leakage parameter; In a second time period after the first time period in the first state, detecting a first characteristic parameter of the driving transistor to obtain a first reference characteristic parameter; Determine a first target characteristic parameter according to the first leakage parameter and the first reference characteristic parameter; the first characteristic parameter is a threshold voltage; the first state is a non-display state; Detecting the leakage amount of the driving transistor through the sensing line to obtain a first leakage parameter; comprising: At an initial moment of the first period, inputting a first reference voltage to the sensing line; At the end of the second period, detecting the voltage of the sensing line to obtain a first target voltage; determining a first leakage parameter according to the first target voltage and the first reference voltage; Detecting a first characteristic parameter of the driving transistor to obtain a first reference characteristic parameter; comprising: Turning on the first transistor and the second transistor, writing a first reference voltage to the control terminal of the driving transistor, and writing a first starting voltage to the second terminal of the driving transistor, so that the driving transistor is turned on; A current is input to the first electrode of the driving transistor, and a voltage at the second electrode of the driving transistor when the driving transistor is turned off is detected as a first reference characteristic parameter.

2. The display panel according to claim 1, wherein: The detection device is also used for: In a first reset period between the first period and the second period, a voltage of the sensing line is reset.

3. The display panel according to claim 1, wherein: The first time period and the second time period have the same duration.

4. The display panel according to claim 1, wherein: The detection device is also used for: In a third time period in the second state of the pixel unit, the first transistor and the second transistor are turned off, and the leakage amount of the driving transistor through the sensing line is detected to obtain a second leakage parameter; In a fourth time period after the third time period in the second state, detecting a second characteristic parameter of the driving transistor to obtain a second reference characteristic parameter; A second target characteristic parameter is determined according to the second leakage parameter and the second reference characteristic parameter.

5. The display panel according to claim 4, wherein: Detecting the leakage amount of the driving transistor through the sensing line to obtain a second leakage parameter; comprising: At an initial moment of the third period, inputting a second reference voltage to the sensing line; At the end of the third period, detecting the voltage of the sensing line to obtain a second target voltage; A second leakage parameter is determined according to the second target voltage and the second reference voltage.

6. The display panel according to claim 5, wherein: The detection device is also used for: The sensing line is reset in a second reset period between the third period and the fourth period.

7. The display panel according to claim 4, wherein: The third time period and the fourth time period have the same duration.

8. The display panel according to claim 4, wherein: The second characteristic parameter is mobility; the second state is a display state; The third period, the second reset period and the fourth period are in a blanking phase.

9. The display panel according to claim 8, wherein: Detecting a second characteristic parameter of the driving transistor to obtain a second reference characteristic parameter; comprising: In the reset phase, the first transistor and the second transistor are turned on, a second reference voltage is input to the control terminal of the driving transistor, the second reference voltage is equal to the sum of the base voltage and the first characteristic parameter; and a reset voltage is input to the sensing line; In the charging stage, the second transistor is turned on, and the driving transistor inputs a driving current to the sensing line under the action of the detection voltage, so that the voltage of the sensing line gradually increases; In the detection phase, the voltage on the sensing line is detected to obtain a detection voltage; In the processing stage, a second reference characteristic parameter of the driving transistor is determined according to the second reference voltage and the detection voltage.

10. A method for detecting a pixel circuit, wherein: The pixel circuit includes a first transistor, a second transistor, a driving transistor and a storage capacitor, wherein a first electrode of the first transistor is connected to a data line; a control terminal of the driving transistor is connected to a second electrode of the first transistor, and a first electrode of the driving transistor is connected to a first power supply terminal; a first electrode of the second transistor is connected to a second electrode of the driving transistor, and a second electrode of the second transistor is connected to a sensing line; The storage capacitor is connected between the control terminal of the driving transistor and the light emitting device; The sensing line is different from the data line; The detection method comprises: In a first time period in a first state of the pixel unit, the first transistor and the second transistor are turned off, and a leakage amount of the driving transistor through the sensing line is detected to obtain a first leakage parameter; In a second period after the first period in the first state, a first characteristic parameter of the driving transistor is detected to obtain a first reference characteristic parameter; the first characteristic parameter is a threshold voltage; the first state is a non-display state; Determine a first target characteristic parameter according to the first leakage parameter and the first reference characteristic parameter; Detecting the leakage amount of the driving transistor through the sensing line to obtain a first leakage parameter; comprising: At an initial moment of the first period, inputting a first reference voltage to the sensing line; At the end of the second period, detecting the voltage of the sensing line to obtain a first target voltage; determining a first leakage parameter according to the first target voltage and the first reference voltage; Detecting a first characteristic parameter of the driving transistor to obtain a first reference characteristic parameter; comprising: Turning on the first transistor and the second transistor, writing a first reference voltage to the control terminal of the driving transistor, and writing a first starting voltage to the second terminal of the driving transistor, so that the driving transistor is turned on; A current is input to the first electrode of the driving transistor, and a voltage at the second electrode of the driving transistor when the driving transistor is turned off is detected as a first reference characteristic parameter.

11. The detection method according to claim 10, wherein: The detection device is also used for: In a third time period in the second state of the pixel unit, the first transistor and the second transistor are turned off, and the leakage amount of the driving transistor through the sensing line is detected to obtain a second leakage parameter; In a fourth time period after the third time period in the second state, detecting a second characteristic parameter of the driving transistor to obtain a second reference characteristic parameter; A second target characteristic parameter is determined according to the second leakage parameter and the second reference characteristic parameter.

12. The detection method according to claim 11, wherein: Detecting the leakage amount of the driving transistor through the sensing line to obtain a second leakage parameter; comprising: At an initial moment of the third period, inputting a second reference voltage to the sensing line; At the end of the third period, detecting the voltage of the sensing line to obtain a second target voltage; A second leakage parameter is determined according to the second target voltage and the second reference voltage.

13. The detection method according to claim 12, wherein: The second characteristic parameter is mobility; the second state is a display state; The third period, the second reset period and the fourth period are in a blanking phase.

14. A method for driving a display panel, wherein: The display panel includes a plurality of pixel units, each of which includes a pixel circuit and a light-emitting device connected to each other; the driving method includes: Detecting a first target characteristic parameter of each of the driving transistors in the pixel circuit using the detection method according to any one of claims 10 to 13; In the display state of the display panel, the data signal of the pixel circuit where the driving transistor is located is compensated according to the first target characteristic parameter of the driving transistor.

15. A display device, wherein: A display panel comprising any one of claims 1 to 9.

Images