Interface potential measuring device and method for untouchable interface

Abstract

The invention discloses an interface potential measuring device and method for an untouchable interface. The device comprises an interface potential measuring module, a laser emitting module, a voltage applying module and an upper computer. The interface potential measuring module comprises a clamping container, an electric field induction optical sensor, a polarization beam splitter, a phase retarder and a polarization camera; the electric field induction optical sensor is of a four-layer structure, and the four-layer structure sequentially comprises a dielectric mirror, a primary electro-optical effect crystal, quartz glass and an indium tin oxide thin film. Linearly polarized light refracted by the polarization beam splitter is introduced into the electric field induction optical sensor through the phase delayer and is reflected by the indium tin oxide film, the quartz glass, the primary electro-optical effect crystal and the dielectric mirror in sequence, and elliptically polarized light is transmitted to the polarization beam splitter through the phase delayer and is collected by the polarization camera. And calculating the interface potential of the untouchable interface according to the phase difference of the elliptically polarized light, and realizing measurement on the basis of avoiding damage to the untouchable interface.

Description

Technical Field

[0001] The present invention relates to the technical field of multilayer material monitoring, and in particular to a device and method for measuring interface potential of an inaccessible interface. Background Art

[0002] Multilayer insulation structures play a key role in the insulation protection of electronic devices and power equipment. Multilayer insulation structures include gas-solid structures and solid-solid structures. Gas-solid structures are such as SF6-epoxy resin, and solid-solid structures are such as silicone gel-ceramic and epoxy resin-ceramic. Related reports show that insulation failures of power and electronic equipment mostly occur at the interface of multilayer dielectric insulation structures. It can be seen that the insulation performance of the interface is directly related to the insulation life of the equipment.

[0003] Measurement is a feasible solution to investigate the interface potential, and its solution is based on the recorded voltage, current, light and other signals. Although isothermal surface potential decay (ISPD), Kelvin probe force microscopy (KPFM) and scanning tunneling microscopy (STM) can only measure the interface potential, they are limited to the accessible interface of gas-solid. They are still powerless for the inaccessible interface of solid-solid. In summary, it is difficult to obtain the interface potential of the inaccessible interface of solid-solid multilayer insulating materials with the existing technology. Summary of the invention

[0004] The present invention provides an interface potential measuring device and method for an inaccessible interface, so as to solve the technical problem that it is difficult to obtain the interface potential of an inaccessible interface of a solid-solid multilayer insulating material in the prior art.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides an interface potential measurement device for an inaccessible interface, comprising: an interface potential measurement module, a laser emission module, a voltage application module and a host computer;

[0006] The interface potential measurement module comprises: a clamping container, an electric field sensing optical sensor, a polarization beam splitter, a phase retarder and a polarization camera; the clamping container, the phase retarder, the polarization beam splitter and the polarization camera are arranged in sequence on the same straight line; a mounting position for mounting an insulating structure to be measured is provided in the clamping container; the electric field sensing optical sensor is a four-layer structure, and the four-layer structure is in sequence: a dielectric mirror, a primary electro-optical effect crystal, quartz glass and an indium tin oxide film; the electric field sensing optical sensor is fixed in the clamping container and is closely attached to the mounting position with one side of the dielectric mirror;

[0007] The polarization beam splitter is used to receive the laser beam from the laser emission module, refract the linearly polarized light, convert it into elliptically polarized light through the phase retarder, and then emit it to the electric field sensing optical sensor;

[0008] The electric field sensing optical sensor is used to receive the elliptically polarized light from the phase retarder, so that the elliptically polarized light passes through the indium tin oxide film, the quartz glass and the primary electro-optical effect crystal in sequence, is reflected by the dielectric mirror, is converted into linearly polarized light by the phase retarder, and then is emitted to the polarization beam splitter;

[0009] The polarization beam splitter is further used to transmit the linearly polarized light from the phase retarder to the polarization camera;

[0010] The polarization camera is used to collect the phase difference of the polarization component of the linearly polarized positive light transmitted by the polarization beam splitter, and upload the phase difference to the host computer;

[0011] The voltage applying module is used to apply a first voltage on the interface of the to-be-insulated structure, apply a second voltage on the indium tin oxide film, and upload the first voltage to the host computer;

[0012] The host computer is used to calculate the interface potential of the insulating structure to be measured according to the phase difference and the first voltage.

[0013] As a preferred solution, the step of calculating the interface potential of the insulating structure to be measured according to the phase difference and the first voltage includes:

[0014] Calculating the potential difference between two sides of the electric field sensing optical sensor according to the phase difference;

[0015] Calculating a voltage division ratio according to the potential difference and the first voltage;

[0016] The interface potential is calculated according to the voltage division ratio and the potential difference.

[0017] As a preferred solution, the calculation formula of the potential difference is:

[0018]

[0019] Where V c represents the potential difference; Δθ represents the phase difference; λ represents the wavelength of the optical signal; γ is the electro-optical coefficient; n0 is the refractive index of the electric field sensing optical sensor when there is no electric field;

[0020] The voltage division ratio is calculated as follows:

[0021]

[0022] In the formula, k v represents the voltage division ratio; V1 represents the first voltage;

[0023] The calculation formula of the interface potential is:

[0024] V f =V c …k v ;

[0025] Where V f Represents the interface potential.

[0026] As a preferred solution, the laser emission module comprises: a laser, a beam homogenizer, a first adjustable aperture and a beam expander;

[0027] The laser is used to generate laser light, so that the laser light passes through the beam homogenizer, the first adjustable aperture and the beam expander in sequence to generate a laser beam that is directed toward the polarization beam splitter.

[0028] As a preferred solution, the interface potential measurement module further includes: a convex lens and a second adjustable aperture;

[0029] The linearly polarized light transmitted by the polarization beam splitter passes through the convex lens and the second adjustable aperture in sequence and is emitted to the polarization camera.

[0030] As a preferred solution, the angle between the polarization direction of the polarization beam splitter and the spatial coordinate is 0°.

[0031] As a preferred solution, the phase retarder is a 1 / 8 glass plate, and the angle between the polarization direction of the 1 / 8 glass plate and the spatial coordinate is 45°.

[0032] As a preferred solution, if the first voltage is an AC voltage, the frequency range of the first voltage is: 10 Hz-10 kHz, and the peak range is: 0.1-40 kV;

[0033] If the first voltage is a direct current voltage, the frequency range of the first voltage is: 0-50 kV.

[0034] As a preferred solution, the second voltage is 0V.

[0035] Based on the above embodiment, another embodiment of the present invention provides a method for measuring the interface potential of an inaccessible interface, comprising:

[0036] Installing the insulating structure to be measured in the installation position of the interface potential measuring device described in the above embodiment;

[0037] Starting the voltage applying module of the interface potential measuring device so that the voltage applying module applies a first voltage on the interface of the insulating structure to be tested and applies a second voltage on the indium tin oxide film;

[0038] Starting the laser emitting module of the interface potential measuring device so that the laser emitting module emits a laser beam toward the polarization beam splitter;

[0039] The interface potential is calculated by the host computer of the interface potential measuring device.

[0040] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0041] The present invention introduces an electric field sensing optical sensor. The linear polarized light refracted by the laser beam through a polarization beam splitter is introduced into the electric field sensing optical sensor through a phase retarder, and is reflected by an indium tin oxide film, quartz glass, a primary electro-optical effect crystal, and a dielectric mirror in sequence. The elliptically polarized light with the potential difference information on both sides of the electric field sensing optical sensor is transmitted through the phase retarder to the polarization beam splitter, and then the elliptically polarized light with the phase difference information on both sides of the electric field sensing optical sensor is collected by a polarization camera. Then, the interface potential of the inaccessible interface is calculated according to the phase difference, and the measurement is achieved without damaging the inaccessible interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a structural schematic diagram of an interface potential measuring device for an inaccessible interface provided by an embodiment of the present invention;

[0043] Figure 2 is a schematic structural diagram of an electric field sensing optical sensor provided by an embodiment of the present invention;

[0044] Figure 3 It is a schematic structural diagram of another device for measuring interface potential of an inaccessible interface provided by an embodiment of the present invention;

[0045] Figure 4 is the measurement result formed by the measurement method of the present invention;

[0046] Figure 5 It is a schematic flow chart of a method for measuring interface potential of an inaccessible interface provided by one embodiment of the present invention;

[0047] Among them, the figure marks of the drawings in the specification are as follows: clamping container 11, top cover 111, bottom cover 112, phase delay 12, polarization beam splitter 13, polarization camera 14, electric field sensing optical sensor 15, dielectric mirror 151, primary electro-optical effect crystal 152, quartz glass 153, indium tin oxide film 154, convex lens 16, second adjustable aperture 17, laser emitting module 2, laser 21, beam homogenizer 22, first adjustable aperture 23 and beam expander 24. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] Embodiment 1

[0050] Please refer to Figure 1 , is a schematic structural diagram of an interface potential measurement device for an inaccessible interface provided by an embodiment of the present invention, comprising: an interface potential measurement module, a laser emission module 2, a voltage application module and a host computer;

[0051] The interface potential measurement module comprises: a clamping container 11, an electric field sensing optical sensor 15, a polarization beam splitter 13, a phase retarder 12 and a polarization camera 14; the clamping container 11, the phase retarder 12, the polarization beam splitter 13 and the polarization camera 14 are arranged in sequence on the same straight line; the clamping container 11 is provided with a mounting position for mounting an insulating structure to be measured; the electric field sensing optical sensor 15 is a four-layer structure, and the four-layer structure is: a dielectric mirror 151, a primary electro-optical effect crystal 152, a quartz glass 153 and an indium tin oxide film 154 in sequence; the electric field sensing optical sensor 15 is fixed in the clamping container 11 and a side of the dielectric mirror 151 is close to the mounting position;

[0052] The polarization beam splitter 13 is used to receive the laser beam from the laser emitting module 2, refract the linearly polarized light, convert it into elliptically polarized light through the phase retarder 12, and then emit it to the electric field sensing optical sensor;

[0053] The electric field sensing optical sensor 15 is used to receive the elliptically polarized light from the phase retarder 12, so that the elliptically polarized light passes through the indium tin oxide film 154, the quartz glass 153 and the primary electro-optical effect crystal 152 in sequence, is reflected by the dielectric mirror 151, is converted into linearly polarized light by the phase retarder 12, and then is emitted to the polarization beam splitter 13;

[0054] The polarization beam splitter 13 is also used to transmit the linearly polarized light from the phase retarder 12 to the polarization camera 14;

[0055] The polarization camera 14 is used to collect the phase difference of the polarization component of the linearly polarized positive light transmitted by the polarization beam splitter 13, and upload the phase difference to the host computer;

[0056] The voltage applying module is used to apply a first voltage on the interface of the to-be-insulated structure, apply a second voltage on the indium tin oxide film 154, and upload the first voltage to the host computer;

[0057] The host computer is used to calculate the interface potential of the insulating structure to be measured according to the phase difference and the first voltage.

[0058] Please note that, please refer to Figure 2 , is a schematic diagram of the structure of an electric field sensing optical sensor 15 provided by an embodiment of the present invention. The electric field sensing optical sensor 15 includes a dielectric mirror 151, a primary electro-optical effect crystal 152, a quartz glass 153 and an indium tin oxide film 154. The indium tin oxide film 154 is attached to the bottom of the quartz glass 153, the primary electro-optical effect crystal 152 is placed on the top of the quartz glass 153, and a dielectric mirror 151 is arranged above the primary electro-optical effect crystal 152. The dielectric mirror 151 is fitted with the insulating structure to be measured. The dielectric mirror 151 is a mirror surface composed of multiple layers of thin dielectric materials on one side of the primary electro-optical effect crystal 152; the primary electro-optical effect crystal 152 includes Li NbO3 crystal, Li TiO3 crystal, KDP crystal, Bi 12SiO20 (BSO) crystal, and Bi4GeO12 (BGO) crystal. The quartz glass 153 is bonded to the primary electro-optical effect crystal 152 by glue on the other side of the primary electro-optical effect crystal 152 away from the dielectric mirror 151. The indium tin oxide film 154 is deposited on the other side of the quartz glass 153 away from the primary electro-optical effect crystal 152 .

[0059] The clamping container 11 is provided with a top cover 111 and a bottom cover 112 to fix the electric field sensing optical sensor 15 and the insulating structure to be measured. The clamping container 11 body, the top cover 111 and the bottom cover 112 are all insulators. The bottom of the electric field sensing optical sensor 15 is fixed by the bottom cover 112, and the insulating structure to be measured is fixed by the top cover 111.

[0060] The present invention applies a first voltage on the interface of the insulating structure on the waiting side and applies a second voltage on the indium tin oxide film 154, so that the carrier between the common voltage of the interface of the insulating structure on the waiting side and the electric field sensing optical sensor 15 generates a voltage difference on both sides of the primary electro-optical effect crystal 152.

[0061] The continuous laser beam of fixed wavelength and light intensity emitted by the laser emitting module 2 is refracted by the polarization beam splitter 13, and the linearly polarized light is introduced into the electric field sensing optical sensor 15 through the phase retarder 12, and is reflected by the indium tin oxide film 154, the quartz glass 153, the primary electro-optical effect crystal 152, and the dielectric mirror 151 in sequence. The elliptically polarized light with the potential difference information on both sides of the electric field sensing optical sensor 15 is transmitted through the phase retarder 12 to the polarization beam splitter 13, and then the elliptically polarized light with the phase difference information on both sides of the electric field sensing optical sensor 15 is collected by the polarization camera 14.

[0062] In a preferred embodiment, the step of calculating the interface potential of the insulating structure to be measured according to the phase difference and the first voltage includes:

[0063] Calculating the potential difference between the two sides of the electric field sensing optical sensor 15 according to the phase difference;

[0064] Calculating a voltage division ratio according to the potential difference and the first voltage;

[0065] The interface potential is calculated according to the voltage division ratio and the potential difference.

[0066] In a preferred embodiment, the calculation formula of the potential difference is:

[0067]

[0068] Where V c represents the potential difference; Δθ represents the phase difference; λ represents the wavelength of the optical signal; γ is the electro-optical coefficient; n0 is the refractive index of the electric field sensing optical sensor 15 when there is no electric field;

[0069] The voltage division ratio is calculated as follows:

[0070]

[0071] In the formula, k v represents the voltage division ratio; V1 represents the first voltage;

[0072] The calculation formula of the interface potential is:

[0073] V f =V c ·k v ;

[0074] Where V f Represents the interface potential.

[0075] It should be noted that the method for characterizing the inaccessible interface potential of the present invention utilizes the primary electro-optic effect of the primary electro-optic effect crystal 152, applies the electric field formed by the potential to the primary electro-optic effect crystal 152, thereby changing the refractive index of the primary electro-optic effect crystal 152, and further changing the polarization direction of the polarized light passing through the primary electro-optic effect crystal 152, thereby collecting the phase difference of the polarization component of the elliptically polarized light, and calculating the inaccessible interface potential. This method allows instantaneous and microscopic state monitoring of the interface potential of the insulating structure to be measured.

[0076] In a preferred embodiment, please refer to Figure 3 , is a schematic structural diagram of another interface potential measuring device for an inaccessible interface provided by an embodiment of the present invention, wherein the laser emitting module 2 comprises: a laser 21, a beam homogenizer 22, a first adjustable aperture 23 and a beam expander 24;

[0077] The laser 21 is used to generate laser light, so that the laser light passes through the beam homogenizer 22 , the first adjustable aperture 23 and the beam expander 24 in sequence to generate a laser beam that is directed toward the polarization beam splitter 13 .

[0078] In a preferred embodiment, please refer to Figure 3 , is a schematic structural diagram of another interface potential measuring device for an inaccessible interface provided by an embodiment of the present invention, wherein the interface potential measuring module further includes: a convex lens 16 and a second adjustable aperture 17;

[0079] The linearly polarized light transmitted by the polarization beam splitter 13 passes through the convex lens 16 and the second adjustable aperture 17 in sequence, and is emitted to the polarization camera 14 .

[0080] In a preferred embodiment, the angle between the polarization direction of the polarization beam splitter 13 and the spatial coordinate is 0°.

[0081] In a preferred embodiment, the phase retarder 12 is a 1 / 8 glass plate, and the angle between the polarization direction of the 1 / 8 glass plate and the spatial coordinate is 45°.

[0082] In a preferred embodiment, if the first voltage is an AC voltage, the frequency range of the first voltage is: 10 Hz-10 kHz, and the peak range is: 0.1-40 kV;

[0083] If the first voltage is a direct current voltage, the frequency range of the first voltage is: 0-50 kV.

[0084] In a preferred embodiment, the second voltage is 0V.

[0085] In a specific embodiment, the insulating structure to be tested is a 0.5 mm Al 2 O 3 ceramic coated with a 0.3 mm DBC copper plate with silicone gel adhered on one side. The insulating structure to be tested is placed in the mounting position of the clamping container 11 and fixed by the top cover 111. An AC voltage of 50 Hz 6 kVrms is applied to the ceramic copper-clad plate to form a distribution of the interface potential between the silicone gel and the ceramic copper-clad plate. The insulating structure to be tested is tightly combined with the electric field sensing optical sensor 15 through the clamping container 11. A DC voltage of 0 V is applied to the indium tin oxide film 154 on the side of the electric field sensing optical sensor 15 away from the ceramic copper-clad plate. A continuous laser beam 21 with a wavelength of 532nm and a light intensity of 0.50W is emitted by the laser emitting module 2. The linearly polarized light refracted by the polarization beam splitter 13 is introduced into the electric field sensing optical sensor 15 via the phase retarder 12, and is reflected by the indium tin oxide film 154, the quartz glass 153, the primary electro-optical effect crystal 152, and the dielectric mirror 151 in sequence. The elliptically polarized light with the potential difference information on both sides of the electric field sensing optical sensor 15 is transmitted via the phase retarder 12 to the polarization beam splitter 13, and then the elliptically polarized light with the phase difference information on both sides of the electric field sensing optical sensor 15 is collected by the polarization camera 14, and then the inaccessible interface potential is calculated.

[0086] The acquisition rate of the polarization camera 14 is set to 1000fps, the exposure time is 10us-100ms, and the frame rate is 100000-10 frames. The spatial resolution of the system is determined by the object-image distance on the optical path, the object-image distance is set to 1:2, and the size of each pixel is 13.5μm / 2=6.75μm.

[0087] The present invention uses a ceramic copper-clad plate when applying voltage to the interface of the insulating structure to be measured, adheres the ceramic copper-clad plate to the interface of the insulating structure to be measured to which voltage needs to be applied, and energizes the ceramic copper-clad plate to achieve voltage application to the interface of the insulating structure to be measured. The calculated interface potential refers to the interface potential of other areas of the insulating structure to be measured except the copper-clad area.

[0088] See also Figure 4 (a)-(l) show the test results of the phases of 0°, 90°, 180°, and 270° under sinusoidal voltage. The voltage division ratio of the copper layer region is 10.33. Figure 4 (a)-(d) describe the phase difference of the polarization components that make up elliptically polarized light. Figure 4 (e)-(h) describe the potential difference across the electric field sensing optical sensor 15, Figure 4 (i)-(l) describe the interface potential of the insulating structure to be measured.

[0089] Embodiment 2

[0090] Please refer to Figure 2, is a flow chart of a method for measuring the interface potential of an inaccessible interface provided by an embodiment of the present invention, comprising:

[0091] S1, installing the insulating structure to be measured in the installation position of the interface potential measuring device described in the above embodiment;

[0092] S2, starting the voltage applying module of the interface potential measuring device, so that the voltage applying module applies a first voltage on the interface of the insulating structure to be treated, and applies a second voltage on the indium tin oxide film 154;

[0093] S3, starting the laser emitting module 2 of the interface potential measuring device, so that the laser emitting module 2 emits a laser beam to the polarization beam splitter 13;

[0094] S4. The interface potential is calculated by the host computer of the interface potential measuring device.

[0095] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. An interface potential measuring device for an inaccessible interface, characterized in that: include: Interface potential measurement module, laser emission module, voltage application module and host computer; The interface potential measurement module comprises: a clamping container, an electric field sensing optical sensor, a polarization beam splitter, a phase retarder and a polarization camera; the clamping container, the phase retarder, the polarization beam splitter and the polarization camera are arranged in sequence on the same straight line; a mounting position for mounting an insulating structure to be measured is provided in the clamping container; the electric field sensing optical sensor is a four-layer structure, and the four-layer structure is in sequence: a dielectric mirror, a primary electro-optical effect crystal, quartz glass and an indium tin oxide film; the electric field sensing optical sensor is fixed in the clamping container and is closely attached to the mounting position with one side of the dielectric mirror; The polarization beam splitter is used to receive the laser beam from the laser emission module, refract the linearly polarized light, convert it into elliptically polarized light through the phase retarder, and then emit it to the electric field sensing optical sensor; The electric field sensing optical sensor is used to receive the elliptically polarized light from the phase retarder, so that the elliptically polarized light passes through the indium tin oxide film, the quartz glass and the primary electro-optical effect crystal in sequence, is reflected by the dielectric mirror, is converted into linearly polarized light by the phase retarder, and then is emitted to the polarization beam splitter; The polarization beam splitter is further used to transmit the linearly polarized light from the phase retarder to the polarization camera; The polarization camera is used to collect the phase difference of the polarization component of the linearly polarized positive light transmitted by the polarization beam splitter, and upload the phase difference to the host computer; The voltage applying module is used to apply a first voltage on the interface of the to-be-insulated structure, apply a second voltage on the indium tin oxide film, and upload the first voltage to the host computer; The host computer is used to calculate the interface potential of the insulating structure to be measured according to the phase difference and the first voltage.

2. The interface potential measuring device according to claim 1, characterized in that: The step of calculating the interface potential of the insulating structure to be measured according to the phase difference and the first voltage includes: Calculating the potential difference between two sides of the electric field sensing optical sensor according to the phase difference; Calculating a voltage division ratio according to the potential difference and the first voltage; The interface potential is calculated according to the voltage division ratio and the potential difference.

3. The interface potential measuring device according to claim 2, characterized in that: The calculation formula of the potential difference is: Where V c represents the potential difference; Δθ represents the phase difference; λ represents the wavelength of the optical signal; γ is the electro-optical coefficient; n0 is the refractive index of the electric field sensing optical sensor when there is no electric field; The voltage division ratio is calculated as follows: In the formula, k v represents the voltage division ratio; V1 represents the first voltage; The calculation formula of the interface potential is: V f =V c ·k v ; Where V f Represents the interface potential.

4. The interface potential measuring device according to claim 1, characterized in that: The laser emission module comprises: a laser, a beam homogenizer, a first adjustable aperture and a beam expander; The laser is used to generate laser light, so that the laser light passes through the beam homogenizer, the first adjustable aperture and the beam expander in sequence to generate a laser beam that is directed toward the polarization beam splitter.

5. The interface potential measuring device according to claim 1, characterized in that: The interface potential measurement module further includes: a convex lens and a second adjustable aperture; The linearly polarized light transmitted by the polarization beam splitter passes through the convex lens and the second adjustable aperture in sequence and is emitted to the polarization camera.

6. The interface potential measuring device according to claim 1, characterized in that: The angle between the polarization direction of the polarization beam splitter and the spatial coordinate is 0°.

7. The interface potential measuring device according to claim 1, characterized in that: The phase retarder is a 1 / 8 glass plate, and the angle between the polarization direction of the 1 / 8 glass plate and the spatial coordinate is 45°.

8. The interface potential measuring device according to claim 1, characterized in that: If the first voltage is an AC voltage, the frequency range of the first voltage is: 10 Hz-10 kHz, and the peak value range is: 0.1-40 kV; If the first voltage is a direct current voltage, the frequency range of the first voltage is: 0-50 kV.

9. The interface potential measuring device according to claim 1, characterized in that: The second voltage is 0V.

10. A method for measuring the interface potential of an inaccessible interface, characterized in that: include: Installing the insulating structure to be measured in the installation position of the interface potential measuring device as claimed in claim 1; Starting the voltage applying module of the interface potential measuring device so that the voltage applying module applies a first voltage on the interface of the insulating structure to be tested and applies a second voltage on the indium tin oxide film; Starting the laser emitting module of the interface potential measuring device so that the laser emitting module emits a laser beam toward the polarization beam splitter; The interface potential is calculated by the host computer of the interface potential measuring device.

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