Impedance testing circuit, device and method

Abstract

The present invention provides an impedance testing circuit, device, and method. The impedance testing circuit includes: an impedance sampling resistor, wherein the first end of the impedance sampling resistor is connected to a first node, and the first node is connected to a first reference potential; a current amplification module, wherein the input end of the current amplification module is connected to the second end of the impedance sampling resistor; and a voltage amplification module, wherein the input end of the voltage amplification module is connected to the output end of the current amplification module, and the output end of the voltage amplification module is connected to a second node; wherein the impedance to be measured is connected between the first node and the second node, and is connected in parallel with the branch where the impedance sampling resistor, the current amplification module, and the voltage amplification module are located. Through the combined action of the current amplification module and the voltage amplification module, the present invention can sensitively test whether the impedance of the impedance to be measured is within a preset range, thereby achieving effective and rapid detection of whether a panel has a DGS defect.

Description

Technical Field

[0001] The present invention relates to the technical field of display panel testing, and in particular to an impedance testing circuit, device and method. Background Art

[0002] IGZO (Indium Gallium Zinc Oxide) is used as the channel layer material in thin film transistor technology. IGZO technology refers to the process of coating a layer of metal oxide on the active layer of TFT-LCD (Thin Film Transistor Liquid Crystal Display). It is an improved technology based on TFT drive. Its characteristics are high mobility, about 10cm 2 / vs can increase the charge and discharge rate of the TFT to the pixel electrode, improving the pixel response speed and achieving a faster refresh rate (>240Hz). The faster response speed also greatly increases the pixel row scan rate, enabling ultra-high resolution. At the same time, it can reduce transistor size, increase pixel aperture ratio, improve brightness, and reduce power consumption. IGZO's amorphous structure is prepared under low temperature conditions, resulting in good uniformity over large sizes. Its amorphous state and high light transmittance also provide a foundation for its application in flexible and transparent displays.

[0003] However, oxide thin-film transistors (TFTs) manufactured using IGZO technology are prone to DGS (Data Gate Short) defects. DGS is a cross-line defect that occurs during lighting testing of TFT display products. It often occurs in the area where the gate layer overlaps with the source and drain layers. Its cause is an increase in slow overflow in the product or the growth of Cu foreign matter under conditions such as electric fields, high temperatures, and moisture. Furthermore, DGS is progressive due to Cu growth, making it crucial to intercept display panels with DGS before shipment.

[0004] Therefore, a method for detecting DGS defects of a display panel is needed. Summary of the Invention

[0005] The main purpose of the present invention is to provide an impedance testing circuit, device and method for determining whether a display panel has a DGS defect by detecting the voltage across the display panel.

[0006] The present invention provides an impedance testing circuit, which includes: an impedance sampling resistor, wherein a first end of the impedance sampling resistor is connected to a first node, which is connected to a first reference potential; a current amplifying module, wherein an input end of the current amplifying module is connected to a second end of the impedance sampling resistor; and a voltage amplifying module, wherein an input end of the voltage amplifying module is connected to an output end of the current amplifying module, which is connected to a second node; wherein an impedance to be measured is connected between the first node and the second node, and is connected in parallel with a branch where the impedance sampling resistor, the current amplifying module, and the voltage amplifying module are located.

[0007] In one embodiment, the current amplification module includes: an operational amplifier, a current sampling resistor, and a feedback resistor; wherein the positive input terminal of the operational amplifier is connected to the second end of the impedance sampling resistor and the first end of the current sampling resistor, the second end of the current sampling resistor is connected to the second reference potential, the negative input terminal of the operational amplifier is connected to the first end of the feedback resistor, and the second end of the feedback resistor is connected to the output terminal of the operational amplifier.

[0008] In one embodiment, the voltage amplification module includes: a high-voltage generator, which includes: a high-voltage transformer, a diode, a protective resistor, a capacitor, an ammeter and a lightning arrester; wherein, the first end of the secondary coil of the high-voltage transformer and the negative pole of the diode are commonly connected to the output end of the current amplification module, the second end of the secondary coil of the high-voltage transformer is connected to the first end of the capacitor and the bottom end of the lightning arrester, the positive pole of the diode is connected to the first end of the protective resistor, and the second end of the protective resistor is connected to the second end of the capacitor and the top end of the lightning arrester; wherein, the ammeter is connected between the protective resistor and the top end of the lightning arrester.

[0009] In one embodiment, it further includes: a voltage detection device for detecting a voltage difference between the first node and the second node; and a controller for determining whether the impedance to be measured meets a preset requirement based on the voltage difference between the first node and the second node.

[0010] The present invention provides an impedance testing device, comprising: the above-mentioned impedance testing circuit; a first impedance testing needle mold, wherein the first end of the first impedance testing needle mold is connected to the first node of the impedance testing circuit; and a second impedance testing needle mold, wherein the first end of the second impedance testing needle mold is connected to the second node of the impedance testing circuit; wherein the impedance to be measured is connected between the second end of the first impedance testing needle mold and the second end of the second impedance testing needle mold.

[0011] In one embodiment, the device further includes: an impedance test switch, wherein a first end of the impedance test switch is connected to a first node of the impedance test circuit, and a second end of the impedance test switch is connected to a first reference potential.

[0012] In one embodiment, the impedance test switch comprises a touch switch.

[0013] In one embodiment, when the impedance testing circuit includes a controller, the impedance testing device further includes: an alarm, which is connected to the controller and is configured to generate an alarm when the controller determines that the impedance to be measured does not meet preset requirements.

[0014] In one embodiment, the impedance to be measured includes a display panel to be tested; the impedance to be measured is connected between the second end of the first impedance test needle mold and the second end of the second impedance test needle mold, including: the ITO layer of the display panel to be tested is connected between the second end of the first impedance test needle mold and the second end of the second impedance test needle mold.

[0015] The present invention provides an impedance testing method, which is applied to the above-mentioned impedance testing circuit or the above-mentioned impedance testing device. The method includes: connecting the impedance to be measured between a first node and a second node, and obtaining the voltages of the first node and the second node respectively; calculating the voltage difference between the first node and the second node, and comparing the voltage difference with a preset voltage threshold. When the voltage difference is greater than the preset voltage threshold, it is determined that the impedance to be measured does not meet the preset requirements.

[0016] The present invention can sensitively test whether the impedance of the impedance to be measured is within a preset range through the joint action of the current amplification module and the voltage amplification module, thereby realizing effective and rapid detection of whether a panel has a DGS defect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which constitute a part of the present application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0018] Figure 1 Schematic diagram of an impedance testing circuit according to an embodiment of the present application;

[0019] Figure 2 Schematic diagram of the test principle of an impedance testing device according to an embodiment of the present application;

[0020] Figure 3 Schematic diagram of the connection positions of the first and second impedance test needle molds and the conductive layer according to an embodiment of the present application;

[0021] Figure 4 Schematic diagram of the appearance of an impedance testing device according to an embodiment of the present application;

[0022] Figure 5 A schematic diagram of the appearance of a JIG fixture (Java Information Group information processing device) in the related art;

[0023] Figure 6 is a schematic diagram of a current amplifier according to an embodiment of the present application;

[0024] Figure 7 is a schematic diagram of a voltage amplifier according to an embodiment of the present application;

[0025] Figure 8 1 is a schematic structural diagram of an MCU (Microcontroller Unit) according to an embodiment of the present application;

[0026] Figure 9 Schematic diagram of the structure of the first and second impedance test needle molds according to an embodiment of the present application;

[0027] Figure 10 Schematic diagram of an alarm according to an embodiment of the present application. DETAILED DESCRIPTION

[0028] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] Panels with abnormal DGS, which pose a reliability risk, have internal Cu growth or foreign matter, causing the overall impedance of the panel to differ from that of normal products. The prior art lacks the impedance testing solution disclosed in this application. As a result, DGS may only be discovered after reliability testing or long-term use, resulting in a poor user experience and complaints. DGS manifests itself in the terminal as poor cross-hatching on the display screen. Therefore, the impedance testing solution of this application is designed to intercept panels with abnormal DGS on the production line.

[0030] Example 1

[0031] This embodiment provides an impedance testing circuit. Figure 1 FIG. 1 is a schematic diagram of an impedance test circuit according to an embodiment of the present application. Figure 1 As shown, the impedance testing circuit of this embodiment may include: an impedance sampling resistor Rx, wherein a first end of the impedance sampling resistor Rx is connected to a first node A, which is connected to a first reference potential; a current amplifying module 110, wherein an input end of the current amplifying module 110 is connected to a second end of the impedance sampling resistor Rx; and a voltage amplifying module 120, wherein an input end of the voltage amplifying module 120 is connected to an output end of the current amplifying module 110, and an output end of the voltage amplifying module 120 is connected to a second node B. The impedance to be measured is connected between the first node A and the second node B, and is connected in parallel with the branch where the impedance sampling resistor Rx, the current amplifying module 110, and the voltage amplifying module 120 are located.

[0032] Using the impedance test circuit of this embodiment, an input voltage can be applied to the impedance under test through the first node A. Simultaneously, the same input voltage Vin is applied through the first node to the branch containing the impedance sampling resistor Rx, the current amplification module 110, and the voltage amplification module 120. The voltage difference V between the first and second nodes A and B is determined by detecting the voltage Vout at the second node B. Since the voltages across a parallel circuit are equal, this voltage difference can be used to determine whether the impedance under test is excessive. Impedance is a parameter related to circuit structure. In a circuit with resistance, inductance, and capacitance, the resistance to current flow is called impedance.

[0033] The impedance to be measured can be the internal impedance of the panel to be tested. DGS is caused by the growth of Cu foreign matter or the presence of slow overflow within the panel. The overall impedance of a panel without Cu foreign matter or slow overflow remains essentially unchanged and remains relatively low. The presence of Cu foreign matter or slow overflow causes the panel's impedance to be higher than that of a panel without Cu foreign matter or slow overflow. Therefore, the impedance of the panel to be tested can be determined by testing the panel's voltage divider. Furthermore, the presence of Cu foreign matter or slow overflow, i.e., whether DGS exists, can be determined based on the panel's impedance.

[0034] like Figure 1 As shown, the voltage Vin at the first node of the Power Integrated Circuit (Power IC) of the PCBA (Printed Circuit Board Assembly) can be input from the PG (Power Generation) production line. V is the voltage difference between Vout and Vin. This voltage difference can be detected using a voltmeter or voltage sensor. If the panel under test does not have a DGS (dead-side gate impedance), meaning the internal impedance is low, V will be a relatively small value. If the panel under test has a DGS (dead-side gate impedance), meaning the internal impedance is high, V will be a relatively large value. Therefore, the presence of a DGS can be determined based on the V value.

[0035] Using the solution of this embodiment, the presence of DGS can be determined by testing the panel's internal impedance. If the panel is free of defects such as Cu foreign matter, its internal impedance remains essentially unchanged. However, if the panel is defective, such as foreign matter, its internal impedance will be greater than that of a normal panel. This solution can screen out products with high impedance (i.e., panels with a DGS risk).

[0036] The impedance difference between a panel with DGS and a normal panel is very slight, at around the milliohm level. Correspondingly, the voltage difference is also very slight. In this embodiment, the current and voltage amplification modules can amplify the weak voltage several times, clearly showing the voltage difference between panels with DGS and normal panels, thereby accurately screening out panels with DGS.

[0037] In one embodiment, the current amplification module 110 may include: an operational amplifier, a current sampling resistor 111, and a feedback resistor Rf; wherein the positive input terminal of the operational amplifier is connected to the second end of the impedance sampling resistor Rx and the first end of the current sampling resistor 111, the second end of the current sampling resistor 111 is connected to a second reference potential, the negative input terminal of the operational amplifier is connected to the first end of the feedback resistor Rf, and the second end of the feedback resistor Rf is connected to the output terminal of the operational amplifier. The second reference potential may include a ground potential.

[0038] In one embodiment, if Figure 1 As shown, the current sampling resistor 111 may include two resistors R1 and R2 with a large resistance difference. For example, the resistance values of R1 and R2 are 0.068Ω and 1Ω respectively.

[0039] In this embodiment, the operational amplifier can amplify the current passing through the impedance sampling resistor. Correspondingly, the voltage divider of the measured impedance is also amplified, making the voltage divider change of the measured impedance more obvious. This is conducive to more accurately determining whether the measured impedance is within the normal value range. Therefore, the solution of this embodiment can be used to accurately screen out panels with DGS.

[0040] Of course, the current amplifying module 110 may also adopt one or more other interconnected devices, as long as it can achieve the effect of amplifying the current, and this application does not limit this.

[0041] In one embodiment, the voltage amplification module 120 may include: a high-voltage generator, the high-voltage generator including: a high-voltage transformer T, a diode D, a protective resistor R, a capacitor C, an ammeter μA and a lightning arrester Cx; wherein, the first end of the secondary coil of the high-voltage transformer T and the negative electrode of the diode D are commonly connected to the output end of the current amplification module, the second end of the secondary coil of the high-voltage transformer T is connected to the first end of the capacitor C and the bottom end of the lightning arrester Cx, the positive electrode of the diode D is connected to the first end of the protective resistor R, and the second end of the protective resistor R is connected to the second end of the capacitor C and the top end of the lightning arrester Cx; wherein, the ammeter μA is connected between the protective resistor R and the top end of the lightning arrester Cx.

[0042] In this embodiment, the voltage division of the impedance to be measured can be further amplified by the high-voltage generator, making the voltage division change of the impedance to be measured more obvious, which is conducive to more accurately determining whether the impedance to be measured is within the normal value range. Therefore, the solution of this embodiment can be used to accurately screen out panels with DGS.

[0043] Of course, the voltage amplification module 120 may also adopt one or more other interconnected devices, as long as it can achieve the effect of amplifying the voltage, and this application does not limit this.

[0044] In one embodiment, the impedance testing circuit may further include: a voltage detection device (not shown in the figure) for detecting the voltage difference between the first node and the second node; and a controller (not shown in the figure) for determining whether the impedance to be measured meets preset requirements based on the voltage difference between the first node and the second node.

[0045] The voltage detection device may include a voltmeter, a voltage sensor, etc., which is not limited in this application.

[0046] The preset requirement can be set based on actual needs. For example, the normal voltage divider of the panel to be tested can be calibrated in advance, and the calibrated voltage divider can be used as the preset voltage threshold. The preset requirement can be that the voltage difference between the first node and the second node is less than or equal to the preset voltage threshold. Of course, other preset requirements can also be set, and this application is not limited to this.

[0047] By integrating a controller into the impedance test circuit, the controller can execute the steps of determining whether the impedance to be measured meets the preset requirements, thereby directly outputting the judgment result, thereby improving the convenience of the impedance test circuit.

[0048] Although this embodiment describes the solution of this embodiment by taking the internal impedance of the panel to be measured as an example, the impedance to be measured may also be other impedances, and this application does not make any specific limitation on this.

[0049] This embodiment, through the combined action of the current amplification module and the voltage amplification module, can sensitively test whether the impedance of the impedance to be measured is within a preset range, thereby enabling effective and rapid detection of whether a panel has a DGS defect.

[0050] Example 2

[0051] This embodiment provides an impedance testing device. Figure 2 Schematic diagram of the test principle of an impedance testing device according to an embodiment of the present application.

[0052] like Figure 2As shown, the impedance testing device of this embodiment may include: the above-mentioned impedance testing circuit 1; a first impedance testing needle module 2, the first end of the first impedance testing needle module 2 is connected to the first node A of the impedance testing circuit; a second impedance testing needle module 3, the first end of the second impedance testing needle module 3 is connected to the second node B of the impedance testing circuit; wherein the impedance to be measured is connected between the second end of the first impedance testing needle module 2 and the second end of the second impedance testing needle module 3.

[0053] like Figure 3 As shown, for the impedance panel to be tested, the distance between the POL (Polarizer) layer and the boundary of the glass layer is approximately 1 mm, and the first impedance test needle mold 2 and the second impedance test needle mold 3 can be crimped on the ITO (Indium Tin Oxide) layer with a width of approximately 1 mm.

[0054] The panel to be tested can be fixed by the first impedance test needle mold 2 and the second impedance test needle mold 3, and voltage can be input to the panel to be tested.

[0055] In one implementation, the impedance testing device of this embodiment may further include: an impedance testing switch 4 , wherein a first end of the impedance testing switch 4 is connected to a first node A of the impedance testing circuit, and a second end of the impedance testing switch 4 is connected to a first reference potential.

[0056] The impedance test circuit can be turned on and off by controlling the impedance test switch 4 .

[0057] In one embodiment, the impedance test switch 4 may include a touch switch, that is, each press triggers a test action.

[0058] The touch switch can prevent the impedance to be measured from being damaged due to long-term power supply.

[0059] In one embodiment, when the impedance testing circuit includes a controller, the impedance testing device further includes: an alarm 5, which is connected to the controller and is configured to generate an alarm when the controller determines that the impedance to be measured does not meet a preset requirement.

[0060] By using an alarm, relevant personnel can be notified in time to handle the impedance that does not meet the preset requirements.

[0061] The positions of the impedance test circuit 1, the first impedance test needle mold 2, the second impedance test needle mold 3, the impedance test switch 4 and the alarm 5 in the impedance test device are as follows: Figure 4 Two impedance test probes are set on both sides, so that the panel to be tested can be connected in parallel to the test circuit. Figure 4The impedance test device in the embodiment can be a JIG fixture, which can be connected to the PCBA Connect of the panel through the first impedance test needle mold of the JIG fixture to input Vin to the panel.

[0062] The probe in the impedance test needle mold contacts the conductive layer of the panel, which can be a common electrode layer. Furthermore, the common electrode can be ITO, the ITO common electrode (ITO on the glass layer, the entire surface will be plated with ITO, and the ITO can be Back ITO (Back Indium Tin Oxide surface indium tin oxide). Its main function is to connect with the Panel GND (PanelGround screen ground) through Ag glue to form a grounding electric field, which releases the internal charge of the Panel and shields the Panel electric field. The display mode of the liquid crystal can be ADS (Advanced Super Dimension Switch, advanced super-dimensional field switching technology) mode). The two impedance test needle molds are connected to the impedance test circuit as a whole. (The contact position between the impedance test needle film and the panel can be changed. It can be located at the bare ITO position in the non-POL area on the left and right edges of the entire panel. Refer to Figure 3 ).

[0063] Figure 5 The JIG fixture in the prior art does not have the function of impedance testing.

[0064] The current amplification module 110 may be a current amplifier, Figure 6 The current amplifier is a schematic diagram of an embodiment of the present invention. The current amplifier includes a power supply, a power electronic circuit, an inductive load, a controller, and other parts. It adopts an output current closed-loop control. After the original current is input, the current is regulated by a current sampling resistor and a transistor series-parallel circuit. The power electronic circuit is integrated in Figure 6 The left half 111, inductive load, controller integration Figure 6 Right half 112.

[0065] The voltage amplification module 120 may be a voltage amplifier, Figure 7 FIG. 1 is a schematic diagram of a voltage amplifier according to an embodiment of the present application. The voltage amplifier can boost a weak voltage to a high voltage output.

[0066] The controller 130 may include a central processing unit, a digital signal processor, a microprocessor (Microcontroller Unit, MCU) or an integrated circuit, etc. Figure 8The figure is a schematic diagram of the structure of an MCU according to one embodiment of the present application. The MCU can be composed of a central processing unit (CPU), memory (ROM and RAM), and an I / O interface. The impedance test program is written into the ROM of the MCU using a downloader. When the CPU runs the impedance test program, if the voltage difference exceeds a preset voltage threshold, the MCU displays the specific data and controls the buzzer to sound an alarm.

[0067] Figure 9 Schematic diagram of the structure of the first and second impedance test needle molds according to an embodiment of the present application. Figure 9 As shown, two insulated elongated pinholes 201 are provided in the vertical direction of each impedance test needle mold. A metal probe (not extending from the elongated pinhole 201) that can be extended and retracted along the hole wall of the elongated pinhole 201 is correspondingly passed through the elongated pinhole 201. The metal probe is pressed against the elastic pressure head 202 so that the metal probe contacts the panel surface, thereby performing an impedance test on the panel.

[0068] Figure 10 This is a schematic diagram of an alarm device according to one embodiment of the present application. Upon receiving an alarm signal from the MCU, the AC signal passes through the coil wrapped around the bracket, generating an alternating magnetic flux on the bracket's core. This alternating magnetic flux, combined with the constant magnetic flux of the magnetic ring, causes the molybdenum sheet to vibrate at the given AC signal frequency and, in conjunction with the resonant cavity, to sound an alarm. This alarm device can also employ a buzzer.

[0069] In one embodiment, the impedance to be measured may include a display panel to be tested; the impedance to be measured is connected between the second end of the first impedance test needle mold 2 and the second end of the second impedance test needle mold 3, and may include: the ITO layer of the display panel to be tested is connected between the second end of the first impedance test needle mold 2 and the second end of the second impedance test needle mold 3.

[0070] Although this embodiment describes the solution of this embodiment by taking the internal impedance of the panel to be measured as an example, the impedance to be measured may also be other impedances, and this application does not make any specific limitation on this.

[0071] This embodiment uses the combined effects of the current amplifier and the voltage amplifier to sensitively test whether the impedance of the impedance to be measured is within a preset range, thereby enabling effective and rapid detection of whether a panel has a DGS defect.

[0072] Example 3

[0073] This embodiment provides an impedance testing method, which is applied to the above-mentioned impedance testing circuit or the above-mentioned impedance testing device. The impedance testing method of this embodiment may include:

[0074] S100: Connecting an impedance to be measured between a first node A and a second node B, and obtaining voltages at the first node A and the second node B respectively.

[0075] S200: Calculate a voltage difference between the first node A and the second node B, compare the voltage difference with a preset voltage threshold, and when the voltage difference is greater than the preset voltage threshold, determine that the impedance to be measured does not meet a preset requirement.

[0076] Using the method of this embodiment, when the impedance to be measured is a panel, the impedance of the panel to be measured can be determined by testing the voltage divider of the panel, and then it can be judged whether Cu foreign matter or slow overflow exists in the panel to be measured based on the impedance of the panel to be measured, that is, whether DGS exists in the panel to be measured.

[0077] Although this embodiment describes the solution of this embodiment by taking the internal impedance of the panel to be measured as an example, the impedance to be measured may also be other impedances, and this application does not make any specific limitation on this.

[0078] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. When the terms "include" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations.

[0079] It should be noted that the terms "first," "second," etc. in the specification, claims, and drawings of this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this manner are interchangeable under appropriate circumstances.

[0080] It should be understood that the exemplary embodiments in this specification can be implemented in a variety of different forms and should not be construed as being limited to the embodiments described herein. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into a single step, and / or a single step may be broken down into multiple steps. These embodiments are provided to make the disclosure of this application thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art, and should not be construed as limiting the present invention.

[0081] Although the spirit and principles of the present invention have been described with reference to several specific embodiments, it should be understood that the present invention is not limited to the specific embodiments disclosed, and the division into various aspects does not mean that the features of these aspects cannot be combined to benefit. Such division is only for the convenience of expression. The present invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. An impedance testing circuit, characterized in that: The impedance testing circuit comprises: an impedance sampling resistor, wherein a first end of the impedance sampling resistor is connected to a first node, and the first node is connected to a first reference potential; a current amplifying module, wherein an input end of the current amplifying module is connected to the second end of the impedance sampling resistor; a voltage amplifying module, wherein an input end of the voltage amplifying module is connected to an output end of the current amplifying module, and an output end of the voltage amplifying module is connected to a second node; The impedance to be measured is connected between the first node and the second node, and is connected in parallel with the branch where the impedance sampling resistor, the current amplification module and the voltage amplification module are located; Also includes: a voltage detection device, configured to detect a voltage difference between the first node and the second node; A controller is configured to determine whether the impedance to be measured meets a preset requirement based on a voltage difference between the first node and the second node.

2. The impedance testing circuit according to claim 1, wherein: The current amplification module includes: an operational amplifier, a current sampling resistor and a feedback resistor; The positive input terminal of the operational amplifier is connected to the second end of the impedance sampling resistor and the first end of the current sampling resistor, the second end of the current sampling resistor is connected to the second reference potential, the negative input terminal of the operational amplifier is connected to the first end of the feedback resistor, and the second end of the feedback resistor is connected to the output terminal of the operational amplifier.

3. The impedance testing circuit according to claim 1, wherein: The voltage amplification module includes: a high voltage generator, and the high voltage generator includes: a high voltage transformer, a diode, a protection resistor, a capacitor, an ammeter and a lightning arrester; The first end of the secondary coil of the high-voltage transformer and the negative pole of the diode are commonly connected to the output end of the current amplification module, the second end of the secondary coil of the high-voltage transformer is connected to the first end of the capacitor and the bottom end of the lightning arrester, the positive pole of the diode is connected to the first end of the protective resistor, and the second end of the protective resistor is connected to the second end of the capacitor and the top of the lightning arrester; wherein the ammeter is connected between the protective resistor and the top of the lightning arrester.

4. An impedance testing device, characterized in that: include: The impedance testing circuit according to any one of claims 1 to 3; a first impedance testing needle die, wherein a first end of the first impedance testing needle die is connected to a first node of the impedance testing circuit; a second impedance testing needle die, wherein a first end of the second impedance testing needle die is connected to a second node of the impedance testing circuit; The impedance to be measured is connected between the second end of the first impedance test needle mold and the second end of the second impedance test needle mold.

5. The impedance testing device according to claim 4, characterized in that: Also includes: An impedance test switch, wherein a first end of the impedance test switch is connected to a first node of the impedance test circuit, and a second end of the impedance test switch is connected to a first reference potential.

6. The impedance testing device according to claim 5, characterized in that: The impedance test switch comprises a touch switch.

7. The impedance testing device according to claim 4, characterized in that: In the case where the impedance testing circuit includes a controller, the impedance testing device further includes: An alarm is connected to the controller and is used to issue an alarm when the controller determines that the impedance to be measured does not meet the preset requirements.

8. The impedance testing device according to claim 4, characterized in that: The impedance to be measured includes a display panel to be measured; The impedance to be measured is connected between the second end of the first impedance test needle mold and the second end of the second impedance test needle mold, including: The conductive layer of the display panel to be tested is connected between the second end of the first impedance test needle mold and the second end of the second impedance test needle mold.

9. An impedance testing method, characterized in that: Applied to the impedance testing circuit according to any one of claims 1 to 3 or the impedance testing device according to any one of claims 5 to 8, the method comprises: Connecting the impedance to be measured between the first node and the second node, and obtaining the voltages of the first node and the second node respectively; A voltage difference between the first node and the second node is calculated, and the voltage difference is compared with a preset voltage threshold. When the voltage difference is greater than the preset voltage threshold, it is determined that the impedance to be measured does not meet a preset requirement.

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