This application claims priority to Chinese Patent Application No. 202111666014.3, titled “CIRCUIT BOARD AND METHOD AND DEVICE RELATED TO THE SAME”, filed on Dec. 30, 2021 with the China National Intellectual Property Administration, which is hereby incorporated by reference in its entirety.
The present disclosure relates to the field of display technology, and in particular to a circuit board and a method for electrical performance detection of a circuit board, and a display panel, a method for fabricating a display panel, and a method for driving a display panel.
A process of fabricating a display panel generally includes several procedures, such as preparation of a circuit board (array substrate, backboard, and the like), assembling of light-emitting elements, and packaging. In the process of fabricating the display panel, an electrical performance test is usually performed after the assembling of light-emitting elements to detect a defect, in order to prevent a defective display panel from flowing into a subsequent procedure. However, for a conventional display panel, even a defect in electrical performance is detected in the electrical performance test after assembling of light-emitting elements, it is impossible to determine whether an abnormality occurs on the circuit board or during the assembling of light-emitting elements.
In view of the above, a circuit board and a method for electrical performance detection of a circuit board, a display panel, a method for fabricating a display panel, and a method for driving a display panel are provided in the present disclosure, in order to solve the problems in the conventional technology, realizing electrical performance detection on a circuit board, preventing a defective circuit board from flowing into a subsequent fabricating procedure, and avoiding waste of assembling resources.
A circuit board includes multiple rows of pixel circuits for progressive scanning, and multiple detection terminals.
Each of the pixel circuits includes a drive device and a detection device. The drive device includes a signal output terminal for outputting a drive signal. The detection device includes an input terminal electrically connected to the signal output terminal, and an output terminal electrically connected to the detection terminal. The detection devices in one row of the pixel circuits are electrically connected to different detection terminals. The detection terminal is electrically connected to an external electrical performance detection circuit.
The detection device is configured to electrically connect the signal output terminal to the detection terminal in a process of electrical performance detection and when a drive signal is outputted from the signal output terminal; and disconnect the signal output terminal from the detection terminal in a process other than the electrical performance detection.
A method for electrical performance detection of a circuit board is further provided in the present disclosure. The method is applicable to detect the circuit board as described above. The method includes:
electrically connecting an electrical performance detection circuit to the detection terminal; and
performing progressive scanning on the pixel circuits; and the detection device electrically connects the signal output terminal to the detection terminal at a moment when the drive signal is outputted from the signal output terminal, in a process of the progressive scanning.
A method for fabricating a display panel is further provided in the present disclosure. The method includes:
providing the circuit board as described above and multiple light-emitting elements;
performing electrical performance detection on the circuit board by the method for the electrical performance detection as described above; and
fixing and electrically connecting the signal output terminals to the light-emitting elements.
A display panel is further provided in the present disclosure. The display panel includes the circuit board as described above and multiple light-emitting elements, where the light-emitting elements are electrically connected to the signal output terminals of the circuit board.
A method for driving a display panel is further provided in the present disclosure. The method is applicable to the display panel as described above. The method includes:
performing progressive scanning on the pixel circuits, and the detection device keeps disconnecting the signal output terminal from the detection terminal in a process of progressive scanning.
The embodiments of the present disclosure are illustrated by, drawings and are described briefly hereinafter. Apparently, the drawings described in the following illustrate only some embodiments of the present disclosure.
The embodiments of the present disclosure are described clearly and completely in conjunction with the drawings of the embodiments of the disclosure hereinafter. It is apparent that the described embodiments are only some, rather than all, embodiments of the present disclosure.
As described in the background section, a process of fabricating a display panel generally includes several procedures, such as preparation of a circuit board (array substrate, backboard, and the like), assembling of light-emitting elements, and packaging. In the process of fabricating the display panel, an electrical performance test is usually performed after the assembling of light-emitting elements to detect a defect, in order to prevent a defective display panel from flowing into a subsequent procedure. However, for a conventional display panel, even a defect in electrical performance is detected in the electrical performance test after assembling of light-emitting elements, it is impossible to determine whether an abnormality occurs on the circuit board or during the assembling of light-emitting elements.
In view of this, a circuit board, a method for electrical performance detection of a circuit board, a display panel, a method for fabricating a display panel, and a method for driving a display panel are provided, in order to effectively solve problems existing in the conventional technology, achieve a purpose of performing electrical performance detection on the circuit board, prevent a defective circuit board from flowing into a subsequent procedure, and also avoid waste of assembling resources.
The embodiments of the present disclosure are as follows, which are described in detail with reference to
Reference is made
Each of the pixel circuits 100 includes a drive device 110 and a detection device 120. The drive device 110 includes a signal output terminal 111 for outputting a drive signal. The detection device 120 has an input terminal electrically connected to the signal output terminal 111, and an output terminal electrically connected to the detection terminal 200. The detection devices 120 in one row of the pixel circuits 100 are electrically connected to different detection terminals 200. The detection terminal 200 is electrically connected to an external electrical performance detection circuit 300.
The detection device 120 is configured to electrically connect the signal output terminal 111 to the detection terminal 200 in a process of an electrical performance detection and when a drive signal is outputted from the signal output terminal 111; and disconnect the signal output terminal 111 from the detection terminal 200 in a process other than the electrical performance detection.
With the circuit board provided in the embodiment of the present disclosure, in the process of the electrical performance detection, a progressive scanning is performed on the pixel circuits to activate a pixel circuit 100. The signal output terminal 111 outputs a drive signal in a light-emission control stage of the pixel circuits 100. At the moment, the detection device 120 electrically connects the signal output terminal 111 to the detection terminal 200, and the drive signal is transmitted to the detection terminal 200 and collected by an electrical performance detection circuit 300 which is electrically connected to the detection terminal 200. The electrical performance detection circuit 300 performs analysis in response to the drive signal, to determine whether the pixel circuit 100 is abnormal. In this way, the electrical performance detection of the circuit board is performed. In addition, in a process other than the electrical performance detection, such as a normal display process of the display panel, the progressive scanning is performed on the pixel circuits to activate a pixel circuit 100. The signal output terminal 111 of the pixel circuit 100 outputs the drive signal. At this moment, the detection device 120 keeps disconnecting the signal output terminal 111 from the detection terminal 200, to prevent a transmission of the drive signal to the detection terminal 200, ensuring a normal screen display on the display panel.
In the embodiment of the present disclosure, the detection devices 120 in one row of the pixel circuits 100 are electrically connected to different detection terminals 200, and a short circuit between the pixel circuits 100 in the same row due to connection to the same detection terminal may be avoided. According to an embodiment of the present disclosure, as shown in
In the embodiment, in a process of the electrical performance detection, the signal output terminal is electrically connected to the detection terminal to detect the drive signal by the electrical performance detection circuit. Thus, whether the circuit board is abnormal is determined, to achieving the electrical performance detection of the circuit board. In addition, in a process other than the electrical performance detection, the signal output terminal is disconnected from the detection terminal to avoid affecting a normal operation of the circuit board. With the embodiments of the present disclosure, the electrical performance detection of the circuit board is realized, a defective circuit board may be prevented from flowing into a subsequent fabricating procedure, and waste of assembling resources may be avoided.
In an embodiment of the present disclosure, the circuit board may be an array substrate, or may be a backlight panel of a liquid crystal display device, which is not specifically limited herein. When the circuit board is an array substrate, the array substrate may be divided into a display area and a non-display area on a periphery of the display area. The pixel circuits may be located in the display area, and the detection terminals may be located in the non-display area. In an embodiment, the non-display area may be provided surrounding the display area.
In an embodiment of the present disclosure, a wiring structure of the circuit board may be optimized to obtain a simplified circuit structure of the circuit board. As shown in
In an embodiment of the present disclosure, the pixel circuits are controlled to operate in a progressive scanning manner. Therefore, the pixel circuits in the same row work simultaneously to output drive signals, and the pixel circuits in different rows do not operate simultaneously. In the embodiment of the present disclosure, the detection devices in the same row of the pixel circuits are electrically connected to different detection terminals, to prevent a short circuit between the detection devices of the pixel circuits in the same row during operation due to an electrical connection to the same detection terminal. Further, according to an embodiment of the present disclosure, at least one detection terminal is designed to be electrically connected to multiple detection devices. In this way, the number of detection terminals is reduced and the circuit structure of the circuit board is optimized.
In an example, in the circuit board according to an embodiment of the present disclosure, more detection terminals are electrically connected to respective detection devices, and the number of detection terminals is further reduced. As shown in
It should be noted that the pixel circuits in the embodiments of the present disclosure are not limited to being arranged in multiple columns, but may be arranged in other ways, as long as the detection devices in the same row of the pixel circuits are electrically connected to different detection terminals.
In an embodiment of the present disclosure, the detection device is configured to electrically connect the signal output terminal to the detection terminal in a process of an electrical performance detection and when a drive signal is outputted from the signal output terminal; and disconnect the signal output terminal from the detection terminal in a process other than the electrical performance detection. That is, the detection device in the embodiment of the present disclosure may include a controllable switching device that can electrically connect or disconnect the signal output terminal with the detection terminal under the control of a signal.
In the case where the detection device according to an embodiment of the present disclosure includes the first transistor, the signal output terminal and the detection terminal are electrically connected or disconnected by controlling to turn on or turn off the first transistor. In the process of the electrical performance detection, when the signal output terminal outputs a drive signal, the first transistor is controlled to be turned on according to the electrical performance detection signal, to electrically connect the signal output terminal with the detection terminal. When no drive signal is outputted from the signal output terminal, the first transistor is controlled to be turned off according to the electrical performance detection signal, to disconnect the signal output terminal with the detection terminal. In addition, in a process other than the electrical performance detection, such as a display process of the display panel, and the first transistor is controlled to be turned off according to the electrical performance detection signal, to disconnect the signal output terminal with the detection terminal. In this way, a normal display on the display panel is ensured.
In an example, the first transistor in an embodiment of the present disclosure may be an N-type transistor. In this case, in the process of the electrical performance detection and when a drive signal is outputted from the signal output terminal, the electrical performance detection signal is a high-level signal, which controls the first transistor to be turned on. In a process other than the electrical performance detection, the electrical performance detection signal is a low-level signal, which controls the first transistor to be turned off. In an example, the first transistor in an embodiment of the present disclosure may be a P-type transistor. In this case, in the process of the electrical performance detection and when a drive signal is outputted from the signal output terminal, the electrical performance detection signal is a low-level signal to control the first transistor to be turned on. In a process other than the electrical performance detection, the electrical performance detection signal is a high-level signal to control the first transistor to be turned off.
In an embodiment of the present disclosure, all the first transistors may be of a same type. In addition, the electrical performance detection signals to be received by the control terminals of the first transistors in the same row of pixel circuits may be supplied through the same signal output terminal, to simplify a circuit structure. In another example, at least one of the first transistors is of a different type from the rest of the first transistors, which is not specifically limited herein.
In an embodiment of the present disclosure, the electrical performance detection signal may be supplied by a drive chip on the circuit board. In one embodiment, the electrical performance detection signal may be supplied by another circuit structure on the circuit board, such as a circuit structure independent of the drive chip, which is not specifically limited herein.
In combination with
It should be noted that a film layer including the signal output terminal 111, the detection terminal 200 and the circuit for transmitting the electrical performance detection signal Gx (which are collectively referred to as a connecting line) are not specifically limited in the embodiments of the present disclosure. In the case where the terminals of the dual-gate transistor 121 are located in the same layer as the connecting lines, the terminals of the dual-gate transistor 121 may be directly connected to the connecting lines. In the case where the terminals of the dual-gate transistor 121 are located in a different layer from the connecting lines, the terminals of the dual-gate transistor 121 may be connected to the connecting line through via holes, which should be designed based on an actual application.
A circuit structure of the pixel circuit according to an embodiment of the present disclosure is described in more detail below with reference to the accompanying drawings.
In an embodiment of the present disclosure, the first reset device 1101 includes a second transistor T2. The second transistor T2 has a first terminal electrically connected to the first reset voltage terminal Vref1, a second terminal connected to the control terminal of the drive transistor T0, and a control terminal configured to receive the first control signal S1. The data writing device 1102 includes a third transistor T3 and a fourth transistor T4. The third transistor T3 has a first terminal electrically connected to the data voltage terminal Vdata, a second terminal electrically connected to the first terminal of the drive transistor T0, and a control terminal configured to receive the second control signal S2. The fourth transistor T4 has a first terminal electrically connected to the control terminal of the drive transistor T0, a second terminal electrically connected to the second terminal of the drive transistor T0, and a control terminal configured to receive the second control signal S2. The light-emission control device 1103 includes a fifth transistor T5 and a sixth transistor T6. The fifth transistor T5 has a first terminal electrically connected to the first power supply voltage terminal PVDD, a second terminal electrically connected to the first terminal of the drive transistor T0, and a control terminal configured to receive the third control signal S3. The sixth transistor T6 has a first terminal electrically connected to the second terminal of the drive transistor T0, a second terminal electrically connected to the signal output terminal 111, and a control terminal configured to receive the third control signal S3.
The pixel circuit may be further optimized according to an embodiment of the present disclosure.
In an embodiment of the present disclosure, the drive transistor T0, the first transistor 121, the second transistor T2, the third transistor T3, the fourth transistor T4, the fifth transistor T5, the sixth transistor T6 and the seventh transistor T7 may be of the same type. For example, all of transistors are P-type transistors or all of transistors are N-type transistors, which facilitates preparation of the circuit structure. In another example, at least one of the drive transistor T0, the first transistor 121, the second transistor T2, the third transistor T3, the fourth transistor T4, the fifth transistor T5, the sixth transistor T6, and the seventh transistor T7 may be of a different type from the other transistors, which is not specifically limited herein.
A method for electrical performance detection of a circuit board is further provided in an embodiment of the present disclosure. The method is intended to perform electrical performance detection on the circuit board as described in any one of the above embodiments.
In S101, an electrical performance detection circuit is electrically connected to a detection terminal.
In S102, a progressive scanning is performed on pixel circuits, where a detection device electrically connects a signal output terminal to a detection terminal at a moment when a drive signal is outputted from the signal output terminal.
In the method for electrical performance detection according to the embodiment of the present disclosure, in a process of the electrical performance detection, an external electrical performance detection circuit is electrically connected to the detection terminal; then the circuit board is powered on to perform a progressive scanning on the pixel circuits to activate pixel circuits. The signal output terminal is controlled by a drive device to output a drive signal in a process of a light-emission control according to a timing sequence, and at the same time, the signal output terminal is electrically connected to the detection terminal by the detection device. In this way, it is ensured that the drive signal is collected by the electrical performance detection circuit for analysis and diagnose. In this way, whether the pixel circuit and the circuit board are abnormal is determined.
A process of the electrical performance detection according to an embodiment of the present disclosure is described in more detail below with reference to the accompany drawings. As shown in
In the reset stage, the first reset device 1101 connects the control terminal of the drive transistor T0 to the first reset voltage terminal Vref1 in response to the first control signal S1. The data writing device 1102 and the light-emission control device 1103 stop operating in response to respective control signals. The detection device 120 disconnects the signal output terminal 111 from the detection terminal 200.
In the data writing stage, the data writing device 1102, in response to a second control signal S2, connects the first terminal of the drive transistor T0 to a data voltage terminal Vdata, and connects the control terminal of the drive transistor T0 to the second terminal of the drive transistor T0. The first reset device 1101 and the light-emission control device 1103 stop operating in response to respective control signals. The detection device 120 disconnects the signal output terminal 111 from the detection terminal 200.
In the light-emission control stage, the light-emission control device 1103, in response to a third control signal S3, connects the first terminal of the drive transistor T0 to a first power supply voltage terminal PVDD, and connects the second terminal of the drive transistor T0 to the signal output terminal 111. The detection device 120 connects the signal output terminal 111 to the detection terminal 200. The first reset device 1101 and the data writing device 1102 stop operating in response to respective control signals.
A working process of a pixel circuit in the electrical performance detection is described in more detail with reference to
In the reset stage M1, the first control signal S1 is a low-level signal. The second transistor T2 is turned on in response to the control of the low-level signal, to electrically connect the first reset voltage terminal Vref1 to the control terminal of the drive transistor T0. Thus, the drive transistor T0 is reset. The second control signal S2, the third control signal S3 and the electrical performance detection signal Gx are all high-level signals. Thus, the first transistor 121, the third transistor T3, the fourth transistor T4, the fifth transistor T5 and the sixth transistor T6 are all turned off in response to the control of the high-level signals, respectively.
In the data writing stage M2, the second control signal S2 is a low-level signal. The third transistor T3 and the fourth transistor T4 are turned on in response to the low-level signal, to transmit a data voltage of the data voltage terminal Vdata to the drive transistor T0. The first control signal S1, the third control signal S3 and the electrical performance detection signal Gx are all high-level signals. Thus, the first transistor 121, the second transistor T2, the fifth transistor T5 and the sixth transistor T6 are all turned off in response to the control of the high-level signals, respectively.
In the light-emission control stage M3, the third control signal S3 is a low-level signal. The fifth transistor T5 and the sixth transistor T6 are turned on in response to the low-level signal, to transmit a drive signal generated by the drive transistor T0 to the signal output terminal 111. The electrical performance detection signal Gx is a low-level signal. The first transistor 121 is turned on in response to the low-level signal, to transmit the drive signal to the detection terminal 200, and the electrical performance detection circuit can perform analysis and diagnose on the drive signal. The first control signal S1 and the second control signal S2 are both high-level signals. Thus, the second transistor T2, the third transistor T3 and the fourth transistor T4 are all turned off in response to the control of the high-level signals, respectively.
The pixel circuit may be further optimized according to an embodiment of the present disclosure. As shown in
It may be understood that according to the embodiment of the present disclosure, a the drive signal is analyzed and diagnosed by determining whether the light-emission detecting element emits light or not, to determine whether the pixel circuit is abnormal. For example, after collecting the drive signal, the light-emission detecting element may be determined whether the pixel circuit is abnormal by determining whether the light-emission detecting element emits light or not. In another example, after collecting the drive signal, the light-emission detecting element may be determined whether the pixel circuit is abnormal based on brightness or other parameters of the light-emission detecting element, which is not specifically limited herein.
In an embodiment of the present disclosure, the light-emission detecting element may be a light-emitting diode or another type of light-emitting device, which is not specifically limited herein.
It may be understood that the electrical performance detection circuit according to the embodiment of the present disclosure collects a drive signal, the drive signal is buffered by the operational amplifier and then outputted to the sampling circuit. The sampling circuit may be a correlated double sampling (CDS) circuit. The sampling circuit latches the received drive signal and performs a logic operation on the drive signal. Then, the drive signal after logical operation is outputted to the analog-to-digital converter. The analog-to-digital converter detects and quantizes the received drive signal. Then, the quantized drive signal is transmitted to the processor. The processor analyzes the received drive signal to determine whether the pixel circuit is abnormal. For example, the processor may compare the drive signal (such as a drive voltage) with a standard signal (such as a standard voltage). When the drive signal is beyond a range of the standard signal, it is determined that the pixel circuit is abnormal. When the drive signal is within the range of the standard signal, it is determined that the pixel circuit is normal.
A method for fabricating a display panel is further provided in an embodiment of the present disclosure.
In S10, the circuit board as described in any one of the above embodiments and multiple light-emitting elements are provided.
In S20, electrical performance detection is performed on the circuit board by using the method for electrical performance detection as provided in any one of the foregoing embodiments.
In S30, the signal output terminals are fixed and electrically connected to the light-emitting element.
It may be understood that, with method for fabricating a display panel according to the embodiment of the present disclosure, a piece-making process (in which signal output terminals and light-emitting elements are fixed and electrically connected) is required to be carried out after a circuit board is qualified through electrical performance detection, to prevent a defective circuit board from flowing into a subsequent procedure, and avoid waste of assembling resources.
In an embodiment of the present disclosure, the light-emitting element may be a light-emitting diode, which may for example be a Mini-LED.
A display panel is further provided in an embodiment of the present disclosure. The display panel is fabricated by using the fabrication method as described in any one of the embodiments.
In an embodiment of the present disclosure, the display panel is applicable to a mobile terminal, a notebook, a tablet, a computer, a wearable device, and the like, which is not specifically limited herein. In addition, the light-emitting element in an embodiment of the present disclosure may be a light-emitting diode, which may for example be a Mini-LED.
A method for driving a display panel is further provided according to an embodiment of the present disclosure. The method is used for driving the display panel as provided in any one of the above embodiments. The method includes: performing progressive scanning on the pixel circuits, during which the detection device keeps disconnecting the signal output terminal from the detection terminal.
It may be understood that when the display panel as provided in any of the embodiments of the present disclosure is driven to display, the detection device keeps disconnecting the signal output terminal from the detection terminal, in order to prevent a short circuit between the pixel circuits through a detection terminal, to ensure normal display on the display panel.
A process of driving the display panel according to an embodiment of the present disclosure is described in more detail below with reference to an accompanying drawing. Referring to
In the reset stage, the first reset device 1101 connects a control terminal of the drive transistor T0 to a first reset voltage terminal Vref1 in response to a first control signal S1. The data writing device 1102 and the light-emission control device 1103 stop operating in response to respective control signals. The detection device 120 disconnects the signal output terminal 111 from the detection terminal 200.
In the data writing stage, the data writing device 1102, in response to a second control signal S2, connects the first terminal of the drive transistor T0 to a data voltage terminal Vdata, and connects the control terminal of the drive transistor T0 to the second terminal of the drive transistor T0. The first reset device 1101 and the light-emission control device 1103 stop operating in response to respective control signals. The detection device 120 disconnects the signal output terminal 111 from the detection terminal 200.
In the light-emission control stage, the light-emission control device 1103, in response to a third control signal S3, connects the first terminal of the drive transistor T0 to a first power supply voltage terminal PVDD, and connects the second terminal of the drive transistor T0 to the signal output terminal 111. The first reset device 1101 and the data writing device 1102 stop operating in response to respective control signals. The detection device 120 disconnects the signal output terminal 111 from the detection terminal 200.
The method for driving the display panel according to an embodiment of the present disclosure is described in more detail with reference to
In the reset stage M1, the first control signal S1 is a low-level signal. The second transistor T2 is turned on in response to the control of the low-level signal, to electrically connect the first reset voltage terminal Vref1 to the control terminal of the drive transistor T0. Thus, the drive transistor T0 is reset. The second control signal S2, the third control signal S3 and the electrical performance detection signal Gx are all high-level signals. Thus, the first transistor 121, the third transistor T3, the fourth transistor T4, the fifth transistor T5 and the sixth transistor T6 are turned off in response to the control of the high-level signals, respectively.
In the data writing stage M2, the second control signal S2 is a low-level signal. The third transistor T3 and the fourth transistor T4 are turned on in response to the low-level signal, to transmit a data voltage of the data voltage terminal Vdata to the drive transistor T0. The first control signal S1, the third control signal S3 and the electrical performance detection signal Gx are all high-level signals. Thus, the first transistor 121, the second transistor T2, the fifth transistor T5 and the sixth transistor T6 are all turned off in response to the control of the high-level signals, respectively.
In the light-emission control stage M3, the third control signal S3 is a low-level signal. The fifth transistor T5 and the sixth transistor T6 are turned on in response to the low-level signal, to transmit a drive signal generated by the drive transistor T0 to the signal output terminal 111. The first control signal S1, the second control signal S2 and the electrical performance detection signal Gx are all high-level signals. Thus, the first transistor 121, the second transistor T2, the third transistor T3 and the fourth transistor T4 are all turned off in response to the control of the high-level signals, respectively.
A circuit board and a method for electrical performance detection of a circuit board, a display panel, a method for fabricating a display panel, and a method for driving the display panel are provided in the embodiments of the present disclosure. The circuit board includes multiple rows of pixel circuits for progressive scanning, and multiple detection terminals. Each of the pixel circuits includes a drive device and a detection device. The drive device includes a signal output terminal for outputting a drive signal. The detection device has an input terminal electrically connected to the signal output terminal, and an output terminal electrically connected to the detection terminal. The detection devices in one row of the pixel circuits are electrically connected to different detection terminals. The detection terminal is electrically connected to an external electrical performance detection circuit. The detection device is configured to electrically connect the signal output terminal to the detection terminal, in a process of an electrical performance detection and when a drive signal is outputted from the signal output terminal; and disconnect the signal output terminal from the detection terminal in a process other than the electrical performance detection.
In the electrical performance detection according to the embodiment, the signal output terminal is electrically connected to the detection terminal. The electrical performance detection circuit performs a detection on the drive signal to determine whether the circuit board is abnormal, achieving the electrical performance detection of the circuit board. In addition, in the process other than the electrical performance detection, the signal output terminal is disconnected from the detection terminal to avoid affecting a normal operation of the circuit board. With the embodiments of the present disclosure, the electrical performance detection of the circuit board is realized, a defective circuit board may be prevented from flowing into a subsequent fabricating procedure, and waste of assembling resources may be avoided.
Number | Date | Country | Kind |
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202111666014.3 | Dec 2021 | CN | national |