CN109872683B - Pixel circuit, display panel and driving method - Google Patents
Pixel circuit, display panel and driving method Download PDFInfo
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- CN109872683B CN109872683B CN201910244758.2A CN201910244758A CN109872683B CN 109872683 B CN109872683 B CN 109872683B CN 201910244758 A CN201910244758 A CN 201910244758A CN 109872683 B CN109872683 B CN 109872683B
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Abstract
The application provides a pixel circuit, a display panel and a driving method, and provides a novel pixel circuit structure integrated with a fingerprint identification driving circuit and a pixel driving circuit. The pixel circuit includes: the pixel driving circuit and the ultrasonic fingerprint identification driving circuit are coupled to the same first power end, wherein the ultrasonic fingerprint identification driving circuit comprises: the first reset sub-circuit is configured to respond to a first reset signal of a first reset signal terminal to conduct a common voltage signal terminal and a first node in a reset stage; in an acquisition phase, the acquisition sub-circuit is configured to transmit a signal received by the texture recognition device to the first node in response to a first scan signal at a first scan signal terminal, and the first charging sub-circuit is configured to store the signal at the first node.
Description
Technical Field
The present disclosure relates to the field of semiconductor technologies, and in particular, to a pixel circuit, a display panel and a driving method.
Background
In recent years, with the rapid development of technologies, mobile products with biometric identification function gradually enter people's life and work, and fingerprint technology is paid much attention by virtue of its unique identity and applied to secure payment and other user experiences. The pressing type and sliding type fingerprint identification technologies based on the silicon-based process are integrated into mobile products, mobile phone manufacturers such as apple and Huashi apply the fingerprint identification function to mobile phones, but fingerprint devices are generally mostly placed in a non-display area and need to be independently provided with a pressing area, and the key of attention of people in the future is the fingerprint identification technology in the display area.
The fingerprint identification mode of ultrasonic vibration can increase fingerprint identification's the degree of accuracy, because the below information of genuine leather that the ultrasonic wave technique can detect the finger, compares other optics fingerprint and capacitanc fingerprint identification technique, and ultrasonic fingerprint identification technique interference killing feature is stronger, consequently can reach more accurate identification mode.
However, the display device of the prior art has the problem of poor integration level of the fingerprint identification driving circuit and the pixel driving circuit.
Disclosure of Invention
The application provides a pixel circuit, a display panel and a driving method, and provides a novel pixel circuit structure integrated with a fingerprint identification driving circuit and a pixel driving circuit.
An embodiment of the present application provides a pixel circuit, including: the pixel driving circuit and the ultrasonic fingerprint identification driving circuit are coupled to the same first power end, wherein the ultrasonic fingerprint identification driving circuit comprises: the device comprises a line identification device, a first reset sub-circuit, a collection sub-circuit, a first charging sub-circuit and a reading sub-circuit;
in a reset phase, the first reset sub-circuit is configured to turn on the common voltage signal terminal and the first node in response to a first reset signal of the first reset signal terminal; in an acquisition phase, the acquisition sub-circuit is configured to transmit a signal received by the texture recognition device to the first node in response to a first scanning signal of a first scanning signal terminal, and the first charging sub-circuit is configured to store a potential of the first node; in a read phase, the read sub-circuit is configured to read out the signal stored by the first charging sub-circuit in accordance with the potential of the first node and the potential of the first power supply terminal.
In one possible implementation, a first terminal of the first reset sub-circuit is coupled to the first reset signal terminal, a second terminal is coupled to the common voltage signal terminal, and a third terminal is coupled to the first node;
a first end of the acquisition sub-circuit is coupled with the first scanning signal end, a second end of the acquisition sub-circuit is coupled with the line identification device, and a third end of the acquisition sub-circuit is coupled with the first node;
one end of the first charging sub-circuit is coupled with the ground, and the other end of the first charging sub-circuit is coupled with the first node;
the first terminal of the reading sub-circuit is coupled to the first node, the second terminal is coupled to the first power source terminal, and the third terminal is coupled to a reading signal line.
In one possible implementation, the read sub-circuit includes: the first switch transistor, the first source following drive transistor and the rectifier diode;
the gate of the first source follower drive transistor is coupled to the first node, a first pole is coupled to the first power supply terminal, and a second pole is coupled to the first pole of the first switch transistor;
the grid electrode of the first switch transistor is coupled with a first signal control end, and the second pole of the first switch transistor is coupled with the reading signal line;
one end of the rectifying diode is coupled to the first power supply terminal, and the other end of the rectifying diode is coupled to the first node.
In one possible implementation, the first reset sub-circuit includes: a second switching transistor;
the gate of the second switch transistor is coupled to the first reset signal terminal, the first pole is coupled to the common voltage signal terminal, and the second pole is coupled to the first node.
In one possible implementation, the acquisition sub-circuit comprises: a third switching transistor;
the gate of the third switching transistor is coupled to the first scanning signal terminal, the first pole is coupled to the texture recognition device, and the second pole is coupled to the first node.
In one possible implementation, the first charging sub-circuit includes: a first capacitor;
one end of the first capacitor is coupled with the ground, and the other end of the first capacitor is coupled with the first node.
In one possible implementation, the pixel driving circuit includes: a second reset sub-circuit, a charge control sub-circuit, a second source follower drive transistor, a second charge sub-circuit, a light emission control sub-circuit, and a light emitting device;
in the reset phase, the second reset sub-circuit is configured to conduct ground with a second node in response to a second reset signal of a second reset signal terminal; in the acquisition phase, the charge control sub-circuit is configured to conduct a data signal terminal with the second node in response to a second scan signal of a second scan signal terminal, and the second charge sub-circuit is configured to store a potential of the second node; in the light emitting phase, the light emission control sub-circuit is configured to control the second source follower driving transistor to drive the light emitting device to emit light in accordance with the potential of the second node and the potential of the first power source terminal.
In one possible embodiment, the first terminal of the second reset sub-circuit is coupled to the second reset signal terminal, the second terminal is coupled to ground, and the third terminal is coupled to the second node;
a first terminal of the charge control sub-circuit is coupled to the second scan signal terminal, a second terminal thereof is coupled to the data signal terminal, and a third terminal thereof is coupled to the second node;
the gate of the second source follower driving transistor is coupled to the second node, the first pole is coupled to a third node, the second pole is coupled to a fourth node, the third node is further coupled to the charge control sub-circuit, and the fourth node is further coupled to the light emission control sub-circuit;
one end of the second charging sub-circuit is coupled with a second power supply end, and the other end of the second charging sub-circuit is coupled with the second node;
the first terminal of the light-emitting control sub-circuit is coupled to the first power terminal, the second terminal is coupled to the second node, and the third terminal is coupled to the light-emitting device.
In one possible implementation, the second reset signal is the same as the first reset signal; the second scan signal is the same as the first scan signal.
The embodiment of the present application further provides a display panel, which includes the pixel circuit provided in the embodiment of the present application.
An embodiment of the present application further provides a driving method of the pixel circuit, which includes:
in the reset stage, a first reset signal is loaded to the first reset signal end, and the common voltage signal end is conducted with the first node through the first reset sub-circuit;
in the acquisition stage, a first scanning signal is loaded to a first scanning signal end, a signal received by the texture recognition device is transmitted to the first node through an acquisition sub-circuit, and the voltage of the first node is stored through the first charging sub-circuit;
in the reading stage, a first control signal is loaded to the first control signal end, and the signal stored by the first charging sub-circuit is read out through the reading sub-circuit according to the potential of the first node and the potential of the first power supply end.
In one possible embodiment, the method further comprises:
in the reset stage, a second reset signal is loaded to a second reset signal terminal, and the second node is conducted with the ground through a second reset sub-circuit;
in the acquisition stage, a second scanning signal is loaded to a second scanning signal end, a data signal end is conducted with the second node through a charging control sub-circuit, and the potential of the second node is stored through a second charging sub-circuit;
and in the light-emitting stage, the light-emitting control sub-circuit controls the second source following driving transistor to drive the light-emitting device to emit light according to the potentials of the second node and the first power supply end.
The embodiment of the application has the following beneficial effects: the pixel circuit provided by the embodiment of the application comprises: the pixel driving circuit and the ultrasonic fingerprint identification driving circuit are coupled to the same first power end, wherein the ultrasonic fingerprint identification driving circuit comprises: the first reset sub-circuit is configured to respond to a first reset signal of a first reset signal terminal to conduct a common voltage signal terminal and a first node in a reset stage; in an acquisition phase, the acquisition sub-circuit is configured to transmit a signal received by the texture recognition device to the first node in response to a first scanning signal of a first scanning signal terminal, and the first charging sub-circuit is configured to store a potential of the first node; in the reading stage, the reading sub-circuit is configured to read out the signal stored in the first charging sub-circuit according to the potential of the first node and the potential of the first power source terminal, that is, in this embodiment of the application, the ultrasonic fingerprint identification driving circuit and the pixel driving circuit are connected to the same first power source terminal, and when performing texture identification, the ultrasonic fingerprint identification driving circuit may be compatible with a relevant signal of the pixel driving circuit, so that the fingerprint identification driving circuit and the pixel driving circuit are integrated, and the integration of the ultrasonic fingerprint identification driving circuit and the pixel driving circuit is realized.
Drawings
Fig. 1 is a schematic structural diagram of an ultrasonic fingerprint identification driving circuit according to an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram of a specific ultrasonic fingerprint identification driving circuit according to an embodiment of the present disclosure;
fig. 3 is a schematic structural diagram of a pixel circuit according to an embodiment of the present application;
fig. 4 is a schematic structural diagram of a specific pixel circuit according to an embodiment of the present application;
fig. 5 is a schematic structural diagram of a display panel according to an embodiment of the present disclosure;
fig. 6 is a flowchart illustrating a driving method of a pixel circuit according to an embodiment of the present disclosure;
fig. 7 is a timing diagram of a pixel circuit according to an embodiment of the present disclosure;
fig. 8 is a schematic circuit diagram of a reset phase according to an embodiment of the present disclosure;
fig. 9 is a schematic circuit diagram in an acquisition phase according to an embodiment of the present disclosure;
FIG. 10 is a schematic circuit diagram of a read phase according to an embodiment of the present disclosure;
fig. 11 is a schematic circuit structure diagram in a light emitting phase according to an embodiment of the present disclosure.
Detailed Description
The following describes in detail the implementation process of the embodiments of the present application with reference to the drawings of the specification. It should be noted that the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.
Referring to fig. 1, an embodiment of the present application provides a pixel circuit, including: the pixel driving circuit and the ultrasonic fingerprint identification driving circuit are coupled to the same first power terminal Vdd 1, wherein the ultrasonic fingerprint identification driving circuit comprises: the device comprises a grain identification device Z, a first reset sub-circuit, a collection sub-circuit, a first charging sub-circuit and a reading sub-circuit;
in the Reset phase, the first Reset sub-circuit is configured to conduct the common voltage signal terminal Vcom with the first node a in response to the first Reset signal of the first Reset signal terminal Reset 1; in the acquisition phase, the acquisition sub-circuit is configured to transmit the signal received by the texture recognition device Z to the first node a in response to a first scanning signal of the first scanning signal terminal Scan 1, and the first charging sub-circuit is configured to store the signal of the first node a; in the read phase, the read sub-circuit is configured to read out the signal stored by the first charge sub-circuit in accordance with the potential of the first node a and the potential of the first power supply terminal Vdd 1. The signal may specifically be a current value, a potential, a charge amount or other type of signal.
In specific implementation, the first Reset sub-circuit has a first terminal coupled to the first Reset signal terminal Reset 1, a second terminal coupled to the common voltage signal terminal Vcom, and a third terminal coupled to the first node a; the first end of the acquisition sub-circuit is coupled with the first scanning signal end Scan 1, the second end is coupled with the grain identification device Z, and the third end is coupled with the first node A; one end of the first charging sub-circuit is coupled with the ground, and the other end of the first charging sub-circuit is coupled with the first node A; the first terminal of the read sub-circuit is coupled to the first node a, the second terminal is coupled to the first power terminal Vdd 1, and the third terminal is coupled to the read signal line ReadLine.
The pixel circuit provided by the embodiment of the application comprises: the pixel driving circuit and the ultrasonic fingerprint identification driving circuit are coupled to the same first power terminal Vdd 1, wherein the ultrasonic fingerprint identification driving circuit comprises: the first reset sub-circuit is configured to respond to a first reset signal of the first reset signal terminal to conduct the common voltage signal terminal and a first node in a reset stage; in the acquisition stage, the acquisition sub-circuit is configured to respond to a first scanning signal of a first scanning signal terminal to transmit a signal received by the texture recognition device to a first node, and the first charging sub-circuit is configured to store the signal of the first node; in the reading stage, the reading sub-circuit is configured to read out the signal stored by the first charging sub-circuit according to the potential of the first node and the potential of the first power supply terminal, that is, in this embodiment of the application, the ultrasonic fingerprint identification driving circuit and the pixel driving circuit are connected to the same first power supply terminal, and when performing texture identification, the ultrasonic fingerprint identification driving circuit can be compatible with the relevant signal of the pixel driving circuit, so that the fingerprint identification driving circuit and the pixel driving circuit are integrated, and the integration of the ultrasonic fingerprint identification driving circuit and the pixel driving circuit is realized.
In a specific implementation, the display panel may include a plurality of texture recognition devices, and each texture recognition device may specifically include a transmitting electrode and a receiving electrode that are disposed opposite to each other, and a piezoelectric film layer located between the transmitting electrode and the receiving electrode. When fingerprint identification is carried out, ultrasonic signal transmission is firstly carried out, namely, a receiving electrode Rx of all the line identification devices is loaded with a fixed potential (for example, all the receiving electrodes are loaded with 0 voltage), transmitting electrodes Tx of all the line identification devices are simultaneously loaded with alternating voltage (for example, voltage of plus or minus 5V), and the piezoelectric film layer can deform, so that sound waves are generated and transmitted out. During receiving, a fixed potential is loaded on the transmitting electrodes Tx of all the line recognition devices, the receiving electrodes Rx of all the line recognition devices respectively receive the ultrasonic signals reflected back by the fingers, that is, when receiving the acoustic signals reflected back by the fingers to the piezoelectric film layer, the signals are converted into AC voltage, and the receiving electrodes Rx receive the output signals. Because the valley ridge reflected energy of the finger is different, the reflected signals are different, and the fingerprint detection is realized. In this embodiment of the application, before the signal acquired by the texture recognition device is transmitted to the first node by the acquisition sub-circuit, the ultrasonic signal may be transmitted through the transmitting electrode of the texture recognition device, that is, the alternating voltage signal may be loaded through the transmitting electrode of the texture recognition device between the reset stage and the acquisition stage.
In specific implementation, referring to fig. 2, for the read sub-circuit in the embodiment of the present application, it may specifically include: a first switching transistor T1, a first source follower driving transistor Q1, a rectifier diode S; wherein the first source follower driving transistor Q1 has a gate coupled to the first node A, a first pole coupled to the first power supply terminal Vdd 1, and a second pole coupled to the first pole of the first switching transistor T1; a gate of the first switching transistor T1 is coupled to the first signal control terminal EM 1, and a second pole is coupled to the read signal line ReadLine; the rectifying diode S has one end coupled to the first power terminal Vdd 1 and the other end coupled to the first node a. In the embodiment of the present application, the reading sub-circuit specifically includes a first switching transistor T1, a first source follower driving transistor Q1, and a rectifying diode S, so that the reading sub-circuit can read out the potential stored in the first charging sub-circuit under the control of the first signal control terminal EM 1. The rectifier diode S may intercept and accumulate the reflected square wave signal (or sine wave), and when the first switching transistor T1 is turned on, different read lines may read different current values or potentials or charge amounts.
In a specific implementation, referring to fig. 2, the first reset sub-circuit may specifically include: a second switching transistor T2; the gate of the second switching transistor T2 is coupled to the first Reset signal terminal Reset 1, the first pole is coupled to the common voltage signal terminal Vcom, and the second pole is coupled to the first node a. In the embodiment of the present application, the first Reset sub-circuit includes the second switching transistor T2, and further, the potential of the first node a can be Reset according to the signal of the first Reset signal terminal Reset 1, so as to avoid interference to fingerprint identification when the first node a has other signals during ultrasonic fingerprint identification. The common voltage signal terminal Vcom may be the same as a signal of the common voltage terminal of the pixel driving circuit, that is, the ultrasonic fingerprint identification driving circuit may be compatible with the common voltage signal of the pixel driving circuit.
In a specific implementation, referring to fig. 2, the acquisition sub-circuit may specifically include: a third switching transistor T3; the gate of the third switching transistor T3 is coupled to the first Scan signal terminal Scan 1, the first pole is coupled to the texture recognition device Z, and the second pole is coupled to the first node a. In the embodiment of the present application, the collecting sub-circuit includes the third switching transistor T3, so that the collecting sub-circuit can transmit the signal received by the texture recognition device Z to the first node according to the first scanning signal. The first scanning signal of the first scanning signal terminal may be specifically the same as a scanning signal for turning on the gate lines line by line when the pixel driving circuit displays, that is, the ultrasonic fingerprint identification driving circuit may also be compatible with the scanning signal of the pixel driving circuit.
In practical implementation, referring to fig. 2, the first charging sub-circuit specifically includes: a first capacitor C1; wherein one terminal of the first capacitor C1 is coupled to ground and the other terminal is coupled to the first node a. In the embodiment of the present application, the first charging sub-circuit includes the first capacitor C1, so that the potential of the first node a can be stored.
In specific implementation, for the pixel driving circuit in the embodiment of the present application, as shown in fig. 3, the pixel driving circuit may specifically include: a second reset sub-circuit, a charging control sub-circuit (which may specifically include the charging control sub-circuit 1 and the charging control sub-circuit 2), a second source follower driving transistor Q2, a second charging sub-circuit, a light emission control sub-circuit (which may specifically include the light emission control sub-circuit 1 and the light emission control sub-circuit 2), and a light emitting device OLED; in the Reset phase, the second Reset sub-circuit is configured to conduct ground with the second node B in response to a second Reset signal of the second Reset signal terminal Reset 2; in the acquisition phase, the charging control sub-circuit is configured to conduct the data signal terminal Vdate with the second node B in response to a second scanning signal of the second scanning signal terminal Scan 2, and the second charging sub-circuit is configured to store a potential of the second node B; in the light emitting phase, the light emission control sub-circuit is configured to control the second source follower driving transistor to drive the light emitting device to emit light in accordance with the potential of the second node B and the potential of the first power source terminal Vdd 1.
Specifically, the first terminal of the second Reset sub-circuit is coupled to the second Reset signal terminal Reset 2, the second terminal is coupled to ground, and the third terminal is coupled to the second node B; a first terminal of the charge control sub-circuit is coupled to the second Scan signal terminal Scan 2, a second terminal thereof is coupled to the data signal terminal Vdate, and a third terminal thereof is coupled to the second node B; the gate of the second source follower driving transistor Q2 is coupled to a second node B, the first pole is coupled to a third node C, the second pole is coupled to a fourth node D, the third node C is further coupled to the charge control sub-circuit, and the fourth node D is further coupled to the light emission control sub-circuit; one terminal of the second charging sub-circuit is coupled to the second power supply terminal Vdd2, and the other terminal is coupled to the second node B; the light emission control sub-circuit has a first terminal coupled to the first power terminal Vdd 1, a second terminal coupled to the second node B, and a third terminal coupled to the light emitting device OLED.
In the embodiment of the application, the pixel driving circuit and the ultrasonic fingerprint identification driving circuit reset the corresponding nodes in the same reset stage, and charge the corresponding nodes in the same acquisition stage, the second reset signal may be specifically the same as the first reset signal, and the second scan signal may be specifically the same as the first scan signal, so that the high value-added function integration of the ultrasonic fingerprint identification driving circuit and the pixel driving circuit is realized.
In a specific implementation, referring to fig. 4, the second reset sub-circuit includes a fourth switching transistor T4; the gate of the fourth switching transistor T4 is coupled to the second Reset signal terminal Reset 2, the first pole is coupled to ground, and the second pole is coupled to the second node B. In the embodiment of the present application, the second reset sub-circuit includes the fourth switching transistor T4, and when the fourth switching transistor T4 is turned on, the reset of the potential of the second node B can be further achieved.
In a specific implementation, referring to fig. 4, the charge control sub-circuit may specifically include: a fifth switching transistor T5, a sixth switching transistor T6; a gate of the fifth switching transistor T5 is coupled to the second Scan signal terminal Scan 2, a first pole is coupled to the data signal terminal Vdate, and a second pole is coupled to the third node C; the sixth switching transistor T6 has a gate coupled to the third Scan signal terminal Scan 3, a first pole coupled to the fourth node D, and a second pole coupled to the second node B, wherein the signal of the third Scan signal terminal Scan 3 is the same as the signal of the second Scan signal terminal Scan 2. In the embodiment of the present application, the charge control sub-circuit includes a fifth switching transistor T5 and a sixth switching transistor T6, and further when the fifth switching transistor T5, the second source follower driving transistor Q2, and the sixth switching transistor T6 are turned on, the charging from the data signal terminal Vdate to the second node B may be achieved.
In particular implementation, referring to fig. 4, the second charging sub-circuit includes a second capacitor C2; the second capacitor C2 has one terminal coupled to the second power supply terminal Vdd2 and the other terminal coupled to the second node B. In the embodiment of the present application, the second charging sub-circuit includes the second capacitor C2, so that the potential of the second node B can be stored.
In a specific implementation, referring to fig. 4, the light-emitting control sub-circuit may specifically include: a seventh switching transistor T7, an eighth switching transistor T8; a gate of the seventh switching transistor T7 is coupled to the second signal control terminal EM 2, a first pole is coupled to the first power source terminal Vdd 1, and a second pole is coupled to the third node C; the eighth switching transistor T8 has a gate coupled to the third signal control terminal EM3, a first pole coupled to the fourth node D, and a second pole coupled to the light emitting device OLED, wherein the signal of the third signal control terminal EM3 is the same as the signal of the second signal control terminal EM 2. In the embodiment of the present application, the light emission control sub-circuit includes a seventh switching transistor T7 and an eighth switching transistor T8, and when the seventh switching transistor T7 and the eighth switching transistor T8 are turned on, the light emitting device OLED can be driven to emit light by the second source follower driving transistor Q2 according to the first power source terminal Vdd 1 and the potential of the second node B.
The embodiment of the application also provides a display panel, which comprises the pixel circuit provided by the embodiment of the application.
In specific implementation, referring to fig. 5, each texture recognition device Z is located in a gap between adjacent light emitting devices OLED, and each texture recognition device Z includes an emitting electrode 33 and a receiving electrode 31 that are oppositely disposed, and a piezoelectric film layer 32 located between the emitting electrode 33 and the receiving electrode 31, where the receiving electrode 31 is disposed on the same layer as the source/drain electrode 2, and the emitting electrode 33 is disposed on the same layer as a gate electrode (not shown in fig. 5); or, the receiving electrode 31 and the gate are arranged in the same layer, and the emitting electrode 33 and the source and drain are arranged in the same layer; alternatively, the receiving electrode 31 is provided in the same layer as one of the source/drain electrode and the gate electrode, and the emitting electrode 33 is provided in the same layer as the pixel electrode 41. In the embodiment of the application, the receiving electrode and the grid electrode are arranged at the same layer, and the emitting electrode and the source and drain electrodes are arranged at the same layer; or the receiving electrode and the source and drain electrodes are arranged on the same layer, and the emitting electrode and the grid electrode are arranged on the same layer; or the receiving electrode, the source drain electrode and the grid electrode are arranged on the same layer, and the emitting electrode and the pixel electrode are arranged on the same layer, so that the texture recognition device can be formed while the thin film transistor and the pixel electrode are manufactured, and the manufacturing process of the display panel integrated with the texture recognition device can be simplified.
Referring to fig. 6, an embodiment of the present application further provides a driving method of a pixel circuit provided in the embodiment of the present application, including:
step S101, in a reset stage, a first reset signal is loaded to the first reset signal terminal, and the common voltage signal terminal is conducted to the first node through the first reset sub-circuit.
Step S102, in the acquisition stage, a first scanning signal is loaded to a first scanning signal end, a signal received by the texture recognition device is transmitted to a first node through the acquisition sub-circuit, and the signal of the first node is stored through the first charging sub-circuit.
Step S103, in the reading stage, a first control signal is loaded to the first control signal terminal, and the signal stored in the first charging sub-circuit is read out through the reading sub-circuit according to the potential of the first node and the potential of the first power source terminal.
In specific implementation, the driving method in the embodiment of the present application further includes:
in the resetting stage, a second resetting signal is loaded to the second resetting signal terminal, and the second node is conducted with the ground through the second resetting sub-circuit;
in the acquisition stage, a second scanning signal is loaded to a second scanning signal end, the data signal end is conducted with a second node through a charging control sub-circuit, and the potential of the second node is stored through a second charging sub-circuit;
and in the light-emitting stage, the second source following driving transistor is controlled by the light-emitting control sub-circuit to drive the light-emitting device to emit light according to the potential of the second node and the first power supply end.
In specific implementation, the voltage loaded by the data signal terminal in the acquisition phase is equal to the sum of the voltage loaded by the first power supply terminal in the light-emitting phase and the threshold voltage of the second source follower driving transistor. In this embodiment, the voltage loaded by the data signal terminal in the acquisition phase is equal to the sum of the voltage loaded by the first power terminal in the light-emitting phase and the threshold voltage of the second source follower driving transistor, that is, the potential charged to the second node by the charge control sub-circuit in the acquisition phase is Vdata+VthThe formula of the saturation current of the second source follower driving transistor Q2 can be obtained as follows:
I＝K(VGS-Vth)2＝K[(Vdata+Vth)-Vdd-Vth]2
＝K(Vdd-Vdata)2
it can be seen from the above equation that the operating current I of the light emitting device at this time is not subject to the threshold voltage V of the second source follower drive transistorthInfluence of (2) only with VddAnd VdataIt is related. Thoroughly solves the problem of threshold voltage (V) caused by the process and long-time operation of the source follower drive transistor TFTth) The problem of drift guarantees the accuracy of signal data.
In order to more clearly understand the driving method of the pixel circuit provided in the embodiment of the present application, the following takes the signal timing diagram given in fig. 7 as an example, and the driving method of the pixel circuit in the embodiment of the present application is illustrated in detail with reference to fig. 8 to 11.
In the Reset phase, as shown in fig. 8, Reset 1 and Reset 2 (i.e. Reset signal in the right diagram of fig. 8) are all loaded with low level signals, the second switching transistor T2 and the fourth switching transistor T4 are turned on, the other transistors are turned off, the common voltage signal terminal Vcom is turned on with the first node a, the potential of the first node a is Vcom reference voltage, the second node B is grounded, and the potential is Vint. The second switch transistor T2 and the fourth switch transistor T4 may be P-type switch transistors.
In the acquisition stage, as shown in fig. 9, Scan 1, Scan 2, and Scan 3 (i.e. Scan signal in right diagram of fig. 9) are all loaded with low level signal, the third switching transistor T3 is turned on, other transistors of the ultrasonic fingerprint identification driving circuit are turned off, when ultrasonic wave is reflected by finger and received by the receiving electrode RX, the piezoelectric film PVDF generates induced electromotive force on one side, the potential of the first node a changes to the voltage after the ultrasonic wave is reflected by the finger, and the voltage is stored at two ends of C1, which generates ultrasonic wave feedback voltage and prepares for the next compensation stage.
Meanwhile, for the pixel driving circuit, the fifth switching transistor T5, the second source follower driving transistor Q2, and the sixth switching transistor T6 are turned on, and the other transistors are turned off, because the second node B is connected to the low potential Vint, in this stage, the second source follower driving transistor Q2 is turned on, the Vdata signal starts to charge the second node B through T5 → Q2 → T6, and the second node B is charged until Vdata + Vth (the voltage difference between the two electrodes of the gate source of M3 is satisfied), and after the charging is completed, the potential of the second node B is maintained at Vdata + Vth. The third switching transistor T3, the fifth switching transistor T5 and the sixth switching transistor T6 may be P-type switching transistors.
In the read phase, referring to fig. 10, the first signal control terminal EM 1 loads a low level signal, the first switching transistor T1 is turned on, the first source follower driving transistor Q1 is turned on, and the read signal line ReadLine can read different current values or potentials or charge amounts. The reason for distinguishing the phase from the display phase is also to consider distinguishing from the display time zone, so that the signal interference is reduced and the signal-to-noise ratio (SNR) is improved to the maximum extent.
In the light emitting phase, as shown in fig. 11, the low level signal is applied to both EM 2 and EM3 (i.e., the EM signal in the right diagram of fig. 11), the potential of the source of the second source follower driving transistor Q2 is connected to Vdd 1, the current passes through T7 → Q2 → T8, and the saturation current formula of the second source follower driving transistor Q2 can be obtained:
I＝K(VGS-Vth)2＝K[(Vdata+Vth)-Vdd-Vth]2
＝K(Vdd-Vdata)2
it can be seen from the above equation that the operating current I of the light emitting device at this time is not subject to the threshold voltage V of the second source follower drive transistorthInfluence of (2) only with VddAnd VdataIt is related. Thoroughly solves the problem of threshold voltage (V) of the source follower TFT caused by the process and long-time operationth) And the drift problem ensures the accuracy of signal data to generate OLED current to drive the OLED device to emit light.
The embodiment of the application has the following beneficial effects: the pixel circuit provided by the embodiment of the application comprises: the pixel drive circuit and the ultrasonic fingerprint identification drive circuit that are coupled in same first power end, wherein, ultrasonic fingerprint identification circuit includes: the first reset sub-circuit is configured to respond to a first reset signal of the first reset signal terminal to conduct the common voltage signal terminal and a first node in a reset stage; in the acquisition stage, the acquisition sub-circuit is configured to respond to a first scanning signal of a first scanning signal terminal to transmit a signal received by the texture recognition device to a first node, and the first charging sub-circuit is configured to store the signal of the first node; in the reading stage, the reading sub-circuit is configured to read out the signal stored by the first charging sub-circuit according to the potential of the first node and the potential of the first power supply terminal, that is, in this embodiment of the application, the ultrasonic fingerprint identification driving circuit and the pixel driving circuit are connected to the same first power supply terminal, and when performing texture identification, the ultrasonic fingerprint identification driving circuit can be compatible with the relevant signal of the pixel driving circuit, so that the fingerprint identification driving circuit and the pixel driving circuit are integrated, and the integration of the ultrasonic fingerprint identification driving circuit and the pixel driving circuit is realized.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.
Claims (10)
1. A pixel circuit, comprising: the pixel driving circuit and the ultrasonic fingerprint identification driving circuit are coupled to the same first power end, wherein the ultrasonic fingerprint identification driving circuit comprises: the device comprises a line identification device, a first reset sub-circuit, a collection sub-circuit, a first charging sub-circuit and a reading sub-circuit;
in a reset phase, the first reset sub-circuit is configured to turn on the common voltage signal terminal and the first node in response to a first reset signal of the first reset signal terminal;
in an acquisition phase, the acquisition sub-circuit is configured to transmit a signal received by the texture recognition device to the first node in response to a first scan signal at a first scan signal terminal, the first charging sub-circuit is configured to store the signal at the first node;
in a read phase, the read sub-circuit is configured to read out the signal stored by the first charge sub-circuit according to the potential of the first node and the potential of the first power supply terminal;
the pixel driving circuit includes: a second reset sub-circuit, a charge control sub-circuit, a second source follower drive transistor, a second charge sub-circuit, a light emission control sub-circuit, and a light emitting device;
in the reset phase, the second reset sub-circuit is configured to conduct ground with a second node in response to a second reset signal of a second reset signal terminal; in the acquisition phase, the charge control sub-circuit is configured to conduct a data signal terminal with the second node in response to a second scan signal of a second scan signal terminal, and the second charge sub-circuit is configured to store a potential of the second node; in the light emitting phase, the light emission control sub-circuit is configured to control the second source follower driving transistor to drive the light emitting device to emit light in accordance with the potential of the second node and the potential of the first power source terminal.
2. The pixel circuit according to claim 1,
a first terminal of the first reset sub-circuit is coupled to the first reset signal terminal, a second terminal thereof is coupled to the common voltage signal terminal, and a third terminal thereof is coupled to the first node;
a first end of the acquisition sub-circuit is coupled with the first scanning signal end, a second end of the acquisition sub-circuit is coupled with the line identification device, and a third end of the acquisition sub-circuit is coupled with the first node;
one end of the first charging sub-circuit is coupled with the ground, and the other end of the first charging sub-circuit is coupled with the first node;
the first terminal of the reading sub-circuit is coupled to the first node, the second terminal is coupled to the first power source terminal, and the third terminal is coupled to a reading signal line.
3. The pixel circuit of claim 2, wherein the read sub-circuit comprises: the first switch transistor, the first source following drive transistor and the rectifier diode;
the gate of the first source follower drive transistor is coupled to the first node, a first pole is coupled to the first power supply terminal, and a second pole is coupled to the first pole of the first switch transistor;
the grid electrode of the first switch transistor is coupled with a first signal control end, and the second pole of the first switch transistor is coupled with the reading signal line;
one end of the rectifying diode is coupled to the first power supply terminal, and the other end of the rectifying diode is coupled to the first node.
4. The pixel circuit of claim 2, wherein the first reset sub-circuit comprises: a second switching transistor;
the gate of the second switch transistor is coupled to the first reset signal terminal, the first pole is coupled to the common voltage signal terminal, and the second pole is coupled to the first node.
5. The pixel circuit of claim 2, wherein the acquisition sub-circuit comprises: a third switching transistor;
the gate of the third switching transistor is coupled to the first scanning signal terminal, the first pole is coupled to the texture recognition device, and the second pole is coupled to the first node.
6. The pixel circuit of claim 2, wherein the first charge sub-circuit comprises: a first capacitor;
one end of the first capacitor is coupled with the ground, and the other end of the first capacitor is coupled with the first node.
7. The pixel circuit according to claim 1,
a first terminal of the second reset sub-circuit is coupled to the second reset signal terminal, a second terminal is coupled to ground, and a third terminal is coupled to the second node;
a first terminal of the charge control sub-circuit is coupled to the second scan signal terminal, a second terminal thereof is coupled to the data signal terminal, and a third terminal thereof is coupled to the second node;
the gate of the second source follower driving transistor is coupled to the second node, the first pole is coupled to a third node, the second pole is coupled to a fourth node, the third node is further coupled to the charge control sub-circuit, and the fourth node is further coupled to the light emission control sub-circuit;
one end of the second charging sub-circuit is coupled with a second power supply end, and the other end of the second charging sub-circuit is coupled with the second node;
the first terminal of the light-emitting control sub-circuit is coupled to the first power terminal, the second terminal is coupled to the second node, and the third terminal is coupled to the light-emitting device.
8. The pixel circuit according to claim 6, wherein the second reset signal is the same as the first reset signal; the second scan signal is the same as the first scan signal.
9. A display panel comprising the pixel circuit according to any one of claims 1 to 8.
10. A method of driving a pixel circuit according to any one of claims 1 to 8, comprising:
in the reset stage, a first reset signal is loaded to the first reset signal end, the common voltage signal end is conducted with the first node through the first reset sub-circuit, a second reset signal is loaded to the second reset signal end, and the second node is conducted with the ground through the second reset sub-circuit;
in the acquisition stage, a first scanning signal is loaded to a first scanning signal end, a signal received by the texture recognition device is transmitted to the first node through an acquisition sub-circuit, the voltage of the first node is stored through a first charging sub-circuit, a second scanning signal is loaded to a second scanning signal end, a data signal end is conducted with the second node through a charging control sub-circuit, and the potential of the second node is stored through a second charging sub-circuit;
in the reading stage, a first control signal is loaded to a first control signal end, and the potential stored by the first charging sub-circuit is read out through a reading sub-circuit according to the potential of the first node and the potential of a first power supply end;
and in the light-emitting stage, the light-emitting control sub-circuit controls the second source following driving transistor to drive the light-emitting device to emit light according to the potentials of the second node and the first power supply end.
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| CN110008939B (en) * | 2019-05-17 | 2021-04-13 | 京东方科技集团股份有限公司 | Fingerprint identification pixel driving circuit, driving method thereof and display panel |
| TWI698849B (en) * | 2019-10-03 | 2020-07-11 | 友達光電股份有限公司 | Pixel circuit |
| CN110728254B (en) * | 2019-10-22 | 2022-03-01 | 武汉华星光电半导体显示技术有限公司 | Optical fingerprint identification circuit and display device |
| CN110827754B (en) * | 2019-11-04 | 2021-05-11 | Oppo广东移动通信有限公司 | Compensating circuit of OLED (organic light emitting diode) driving circuit and display |
| US11455820B2 (en) | 2019-12-06 | 2022-09-27 | Beijing Boe Technology Development Co., Ltd. | Ultrasonic fingerprint identification component, fingerprint identification device and fingerprint identification driving method |
| CN111339916B (en) * | 2020-02-24 | 2023-08-11 | 京东方科技集团股份有限公司 | Pixel circuit, driving method thereof and display panel |
| CN111508413B (en) | 2020-04-23 | 2021-12-21 | 京东方科技集团股份有限公司 | Pixel driving circuit, driving method thereof and display panel |
| CN111968575B (en) * | 2020-09-07 | 2022-10-11 | 京东方科技集团股份有限公司 | Pixel driving circuit, driving method thereof and display device |
| CN113013209B (en) * | 2021-02-19 | 2024-05-24 | 京东方科技集团股份有限公司 | Display panel, preparation method thereof and display device |
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| CN104155785B (en) * | 2014-08-07 | 2016-10-05 | 京东方科技集团股份有限公司 | Array base palte and driving method, display device |
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