KR102350976B1 - Resistance measuring device for conductive fabrics - Google Patents

Abstract

A resistance measuring device for a conductive material is disclosed. According to the present invention, there is provided a resistance measuring device for a conductive material, comprising: a table made of an insulating material on which a flexible conductive material is placed on an upper surface based on a hollow formed through; a press plate made of an insulating material for pressing the upper surface of the conductive material to be laid flat; a probe unit coupled to the hollow at the bottom of the table to be spaced apart from the conductive material to induce an eddy current on the conductive material and generate a predetermined electrical signal from the eddy current; and a control unit configured to measure a sheet resistance value based on the electrical signal generated by being connected to the probe unit. According to the present invention, the measurement of sheet resistance or conductivity of a flexible conductive material can be consistently made in a non-contact manner without damage in a state in which it is flat and not wrinkled at the same position, and it is a general purpose for various types of flexible conductive materials. It can be used, and the error range for the measurement value is also reduced.

Description

RESISTANCE MEASURING DEVICE FOR CONDUCTIVE FABRICS

The present invention relates to a resistance measuring device for a conductive material, and more particularly, a resistance measurement capable of consistently measuring the resistance of a conductive material that is not in the form of a hard flat plate but is flexible within a small error range in a non-contact method. It's about the device.

The reason for measuring the resistance of a conductive article made of cotton is generally to know the electrical properties (conductivity, strength, sensitivity, etc.) of the article, that is, how much current flows through the surface.

For example, the touch screen of a smartphone, which are all conductive articles, ITO (transparent conductive film), Ag nanowire (AgNW), graphene, conductive film or fabric, semiconductor wafer, etc., the surface resistance or conductivity of Through the measurement, it is possible to determine the sensitivity or quality of each electrical characteristic.

As described above, among the methods for measuring the resistance to the conductive article, the 4 probe method is used to measure the surface resistance of a semiconductor wafer on which a thin film is formed by sputtering or deposition, as shown in FIG. 7 (a). method used.

In the four-probe method, four test probes 14, 15, 16, and 17 are brought into contact with the surface of the metal film 12 formed on the substrate 10, and then a current ( This is a method of calculating the resistance component by measuring the potential difference (V) formed in the inner test probes 15 and 16 while I) flows.

In this four-probe method, in the case of a fine vibration environment in which contact between the test probes 14 , 15 , 16 , and 17 and the metal film 12 is not made smoothly, errors easily occur in the measurement values, and the test probes 14 , 15 , The surface of the metal film 12 may be damaged due to excessive pressing of the 16 and 17 , and there is a problem in that periodic replacement is required due to wear of the test probes 14 , 15 , 16 and 17 due to contact.

In order to solve the problem of the four-probe method, a two-sided eddy current method for measuring the surface resistance of a conductive article in a non-contact manner has recently been proposed.

In the non-contact double-sided eddy current method, as shown in FIG. 7(b), the coil 21 is wound around the C-type ferrite core 20, and the high frequency wave is applied to the coil 21 through the high-frequency oscillation circuit 22. It is a measurement method made by applying power.

Specifically, when the semiconductor wafer 24 is inserted into a space spaced apart by several mm at the ends 20a and 20b of the core 20 and high-frequency power is applied, the eddy current induced in the semiconductor wafer 24 is generated by the semiconductor wafer ( 24) is consumed as Joule heat. In this case, the Joule heat consumed is detected through the waveform detection circuit 26 and calculated as the conductivity of the semiconductor wafer 24, that is, the resistance value.

The two-sided eddy current method as described above does not cause problems such as damage to the surface of the target object, generation of dust, or periodic replacement due to wear of the measurement device because the measurement device does not directly contact the surface of the measurement object. There is a point.

However, this method not only requires a large installation space for the C-type ferrite core 20 itself, but also includes a separate device such as a transfer robot to install the semiconductor wafer 24 in a narrow space of the ferrite core 20 . It is also required to secure an installation space for the transfer robot in that it must be accurately positioned, and an operation structure that adjusts the spacing of the cores 20 according to the thickness of the object to be measured must be added or several types of ferrite cores 20 must be provided. There are limitations in its application.

Furthermore, the conventional measuring device is suitable for use on hard materials that do not bend such as semiconductor wafers, but has resistance to materials such as touch screens, transparent conductive films, Ag nanowires, conductive films, or woven/non-woven fabrics made of flexible materials. It is not suitable for reliably measuring the value or conductivity, so a measuring device for a flexible conductive material is required.

An object of the present invention is to measure the sheet resistance or conductivity of materials such as flexible touch screens, transparent conductive films, Ag nanowires, conductive films, or woven/non-woven fabrics in a non-contact method consistently within a small error range. To provide a resistance measuring device for conductive materials suitable for

The object is, the table of insulating material on which a flexible conductive material is placed on the upper surface based on the hollow formed through; a press plate made of an insulating material for pressing the upper surface of the conductive material to be laid flat; a probe unit coupled to the hollow at the bottom of the table to be spaced apart from the conductive material to induce an eddy current on the conductive material and generate a predetermined electrical signal from the eddy current; and a control unit for measuring a sheet resistance value based on the electrical signal generated in connection with the probe unit.

The resistance measuring device for a conductive material is installed between the table and the probe unit to adjust the separation distance, and it characterized in that it further comprises a lifting unit for moving the probe unit in a vertical direction.

The pressure plate is formed to have a size that covers the entire conductive material, and the resistance measuring device for the conductive material is installed between the table and the pressure plate to move the pressure plate up and down and press the conductive material with a predetermined pressure It is characterized in that it further comprises a pressing part.

The pressing unit may include: a pair of pulleys disposed vertically and rotated by the rotational force of the power unit; a belt arranged to span the pair of pulleys, one side of which moves up and down according to the rotation of the pulleys; and a lifting block coupled to the pressing plate while being fixed to one side of the belt to elevate the pressing plate.

The resistance measuring device for the conductive material further includes an attachment portion provided on the pressure plate for adsorbing the conductive material to be flattened, and the attachment portion may include: an empty space formed inside the pressure plate and communicating with the vacuum device; and a plurality of intake holes formed to communicate with the empty space on one surface of the pressing plate for pressing the conductive material.

The resistance measuring device for a conductive material may further include a rotating part for rotating the pressing plate so that the intake hole is positioned upward or downward, respectively.

According to the present invention, a press plate of an insulating material that flatly presses a flexible conductive material placed on the hollow of a table made of insulating material, and a distance from the conductive material at the bottom of the table are coupled to the hollow to induce an eddy current on the conductive material, Due to the probe unit that generates the electrical signal of It can be done consistently in a non-contact method without damage, can be used universally for various types of flexible conductive materials, and has the effect of reducing the error range for measurement values.

1 is a perspective view of a resistance measuring device for a conductive material according to an embodiment of the present invention.
2 is an exploded perspective view in which the main configuration of FIG. 1 is disassembled;
FIG. 3 is a cross-sectional view taken along line AA of FIG. 1 .
4 is a perspective view of a resistance measuring device for a conductive material according to a modified example of the present invention.
FIG. 5 is a cross-sectional view taken along line BB of FIG. 4 .
6 is a graph showing the change trend and error range of the sheet resistance value of the conductive material measured in response to the pressure of the pressing plate of FIG. 1 .
7 is a diagram illustrating a method of measuring resistance of a conventional conductive article, respectively.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in describing the present invention, descriptions of already known functions or configurations will be omitted in order to clarify the gist of the present invention.

1 is a perspective view of a resistance measuring device for a conductive material according to an embodiment of the present invention, FIG. 2 is an exploded perspective view in which the main configuration of FIG. 1 is disassembled, and FIG. 3 is a cross-sectional view taken along line AA of FIG. 4 is a perspective view of a resistance measuring device for a conductive material according to a modified example of the present invention, FIG. 5 is a cross-sectional view taken along the cutting line BB of FIG. 4, and FIG. 6 is a conductive material measured in response to the pressure of the pressure plate of FIG. It is a graph showing the change trend of the sheet resistance value and the error range, and FIG. 7 is a diagram showing a resistance measurement method for a conventional conductive article, respectively.

Top (top), bottom (bottom), left and right (side or lateral), front (front, front), rear (back, back), etc., which refer to directions in the description and claims of the invention, etc. are not used for limiting rights For convenience of explanation, the relative positions between the drawings and the components are determined as a reference, and are followed unless otherwise specifically limited.

The resistance measuring device 100 for a conductive material according to the present invention measures the sheet resistance value or conductivity of the conductive material (CF) in a non-contact manner consistently without damage in a flat, non-wrinkled state at the same position, thereby reducing the error range. On the other hand, it is an invention devised to be universally used for various types of flexible conductive materials (CF).

In order to specifically implement the above-described functions or actions, the resistance measuring device 100 for a conductive material according to the present invention is a table 110, a pressing plate 120, and a probe unit as shown in FIGS. 1 to 3 . 130 , the control unit 140 , the lifting unit 150 and the pressing unit 160 , and the rotating unit 180 and the attachment unit in the configuration of the embodiment as shown in FIGS. 4 and 5 . It may be configured as a modified example further adding (170).

Hereinafter, each configuration described above will be described in detail with reference to the drawings.

First, the table 110 is a component provided to position a flexible conductive material (CF) in an unfolded state on a flat surface, and is composed of a flat top plate 112 and four legs 114 supporting it. , A hollow 113 may be formed through the central portion of the upper plate 112 so that a detection unit, which will be described later, is inserted and fixed from the lower side of the upper plate 112 .

The table 110 may be made of an insulating material such as ceramic, glass, rubber-based material, synthetic resin, or natural resin so that the material of the table 110 itself does not affect the electromagnetic action of the detection unit, which will be described later.

Here, the flexible conductive material (CF) refers to a touch screen, a transparent conductive film, Ag nanowire, a conductive film, or a woven/non-woven fabric, which is produced by various materials and manufacturing methods, is flexible, and allows electrons to flow.

However, the conductive material (CF) of the present invention is a CARBISO M carbon nonwoven fabric manufactured by ELG in which conductive fibers of a predetermined length are woven as shown in FIG. 1, with a fiber length of 40 to 90 mm and a weight per area of 100-500 kg/sqm , the fiber weight tolerance may be ±10%. Of course, alternatively, it may be a flexible material made of a fabric in which a conductive formulation is coated on an elastic fabric mixed with nylon and spandex or the like or a mixture of conductive metal fibers.

Such a flexible conductive material (CF) is cut into a rectangle as shown in FIG. 1 and then for measurement of electrical properties such as sheet resistance or conductivity (standards for judging defects or quality), a table as shown in FIG. It may be arranged in a flat state between the 110 and the pressing plate 120 to be described later.

The pressing plate 120 is a plate-shaped component that presses the upper surface of the flexible conductive material (CF) so that it is flatly placed on the upper plate 112 of the table 110 without being wrinkled or folded. In order to prevent the material itself from affecting the operation, it may be manufactured using an insulating material such as ceramic, glass, rubber-based material, synthetic resin, or natural resin.

At this time, it is sufficient if the pressure plate 120 is manufactured in a shape that can cover the flexible conductive material (CF), which is the measurement target, but it is preferable to form a rectangular shape corresponding to the conductive material (CF) and be larger than the conductive material (CF). do.

Here, the reason why the pressure plate 120 is larger than the conductive material CF is to minimize the effect of an external electromagnetic field on the conductive material CF placed on the table 110 and pressed flat.

The probe unit 130 is spaced apart from the conductive material (CF) at the bottom of the table 110 to generate a predetermined electrical signal corresponding to the sheet resistance value or conductivity, which is an electrical characteristic of the flexible conductive material (CF). G) is a component coupled to the hollow 113 in a state.

In order to induce an eddy current on the conductive material (CF) and generate a predetermined electrical signal from the eddy current, the probe unit 130 specifically has a central core having a predetermined length as shown in FIGS. 2 and 3 . 132, a coil 134 wound around the core 132 and connected to a control unit 140 to be described later, and a housing 136 for accommodating and protecting the core 132 and the coil 134 therein, etc. can be composed of

At this time, the core 132 is a cylindrical component made of a ferrite material, and is inserted into the center of the coil 134 to be described later, thereby concentrating the magnetic flux on the central axis of the coil 134 .

The core 132 is made of a ferrite material having low heat loss, low conductivity, and high magnetic permeability due to the high-frequency magnetic field generated by the coil 134 , but the core 132 is not in direct contact with the coil 134 . ) may be insulated with a thin insulating plate or the efficiency of the coil 134 may be increased by using a dust core.

The coil 134 receives high-frequency AC power from the control unit 140 to be described later (input power from the control unit 140) and forms a magnetic field in which the magnetic flux is alternately changed, so that the conductive object, which is spaced apart (G) As a component for inducing an eddy current in the material CF, the cross-sectional diameter of the conducting wire, the winding of the coil 134, etc. may be appropriately changed according to the type of the conductive material CF to be measured.

Here, the eddy current generated in the conductive material (CF) is the frequency of the AC power, the magnetic permeability, the separation (G) distance between the coil 134 and the conductive material (CF), the size of the detection unit, the type and size of the conductive material (CF), etc. As a current variable based on the parameter of It can be treated as an electrical signal.

The impedance of the coil 134 (and the core 132) changed by the eddy current as described above may be used to derive the sheet resistance or conductivity of the conductive material CF by the control unit 140 to be described later, detailed description will be referred to in the description of the control unit 140 .

The control unit 140 is a component that measures a sheet resistance value, which is an electrical characteristic of the conductive material (CF), based on an electrical signal (impedance of the coil 134 itself, etc.) generated in connection with the above-described probe unit 130 and the like. , may be installed on one side of the table 110 as shown in FIG.

Specifically, the control unit 140 is electrically connected to the above-described probe unit 130 as well as a pressing unit 160 and an attachment unit 170 to be described later, respectively, to control their operation and transmit transmitted signals or data. It can be configured to include a micro controller unit (MCU) capable of processing and storing, a microcomputer, and a modular information processing unit such as an Arduino, a display device that visually displays image information, and a button for setting operation. can

At this time, the information processing unit receives the electrical signal as described above, that is, the impedance change of the coil 134 itself due to the eddy current, separates a specific signal wave through the built-in detection circuit, and uses the built-in A/D converter, etc. It can be configured to convert a signal wave into a digital signal to calculate and store the sheet resistance value, which is an electrical characteristic of the conductive material (CF).

A series of processing processes of the control unit 140 that controls each connected device as described above, processes transmitted and received signals or data, calculates, displays, and stores the sheet resistance value, etc. C, which can be read through the above-described information processing unit , C++, JAVA, is made by coding in a programming language such as machine language, which can be easily made in various ways and forms at the level of those skilled in the art, and detailed description thereof will be omitted.

The lifting unit 150 is a component provided to adjust the separation (G) distance between the conductive material (CF) placed on the table 110 and the detection unit, and is installed between the table 110 and the probe unit 130 . It may be implemented as a well-known operating means capable of moving the probe unit 130 in the vertical direction.

In this case, the known operating means may be various types of operating means, such as a hydraulic cylinder method capable of accurate linear control with a strong pressing force, and a ball screw method consisting of a nut coupled with a screw shaft connected to a motor, etc. and reciprocating in a straight line.

However, the lifting unit 150 according to the embodiment of the present invention, as shown in FIG. 2, the male screw 152 formed along the upper outer peripheral surface of the housing 136 of the probe unit 130, and screw fastening corresponding thereto It is formed along the inner circumferential surface of the hollow 113 as much as possible and is composed of a female screw 154 that elevates the probe unit 130 so that the distance (G) between the conductive material (CF) and the probe unit 130 is in the range of 0.1 mm to 5.0 mm. can be adjusted with

Due to the lifting unit 150 having such a simple structure, the lifting operation of the probe unit 130 can be performed quickly and easily without a special power device in response to the characteristics of the conductive material (CF).

The pressing unit 160 is a component provided to move the pressing plate 120 in the vertical direction and pressing the conductive material (CF) with a predetermined pressure, and is installed between the table 110 and the pressing plate 120 and the pressing plate 120 . Any known operating means capable of elevating up and down may be used.

That is, the pressing unit 160 may also be an operating means of various methods, such as a hydraulic cylinder method capable of accurate linear control with a strong pressing force, a ball screw method consisting of a nut that reciprocates in a straight line coupled to a screw shaft connected to a motor, and the like.

However, the pressing unit 160 according to the embodiment of the present invention minimizes friction, noise, dust generation, etc. according to mechanical operation and implements a pressing force by accurate movement, as shown in FIG. 3 , a power device (not shown) is configured to include a pulley 162, a belt 164 and a lifting block 166 associated with it.

A pair of pulleys 162 is a component that is arranged vertically and rotates by the rotational force of the power unit, and is meshed with or firmly in close contact with a belt 164 to be described later that is vertically arranged and fixed in an annular shape. As a component for guiding the vertical movement of the housing, it may be rotatably installed at the upper and lower ends of the case constituting the housing.

At this time, any one of the pair of pulleys 162 is coupled to a control motor, which is a power device operated and controlled by the controller 140 , to transmit a rotational driving force to the belt 164 .

The belt 164 is a component that is disposed to span a pair of pulleys 162 and one side moves up and down according to the rotation of the pulley 162, and meshes with the outer peripheral surface of the pair of pulleys 162 as described above. or tightly adhered to form an annular shape.

The lifting block 166 is provided between the belt 164 and the pressing plate 120 to elevate the pressing plate 120 , and is fixed to one side of the belt 164 and protrudes toward the pressing plate 120 . to form an integrated coupling with the pressing plate 120 .

As described above, when any one of the pulleys 162 rotates by the power device rotating forward and reverse according to the operation control of the controller 140 and guides the upward movement of the belt 164, the lifting block 166 and the pressing plate ( Since the 120 rises from the table 110, preparation for measurement or replacement of the conductive material CF is easily performed.

Conversely, when any one of the pulleys 162 rotates and guides the downward movement of the belt 164, the lifting block 166 and the pressing plate 120 descend toward the table 110, and the conductive material prepared for measurement or replaced. (CF) can be pressurized to a predetermined pressure.

As a result, not only is it possible to measure general resistance in response to various types of flexible conductive materials (CF), but also non-contact sheet resistance measurement of flexible conductive materials (CF) is accurate and consistent in a flat, non-wrinkled state. can be made possible.

Furthermore, the test result of measuring the sheet resistance of the CARBISO M carbon nonwoven fabric of ELG company mentioned above using the resistance measuring device according to an embodiment of the present invention several tens of times is shown in FIG. 6 .

Referring to FIG. 6, first, in a predetermined pressure range (0.0 KPa to 1.0 KPa), as the pressing force of the pressing plate 120 increases, the error range for the sheet resistance measurement value decreases to a significant level (the interval between the upper and lower blue bars). can

And when the sheet resistance of the conductive material (CF) is measured while maintaining the pressing force of the pressing plate 120 according to the embodiment of the present invention in the range of 0.5 KPa to 1.0 KPa, the relative standard deviation is observed compared to the conventional measurement method IEC 62899. It can be seen that it is low (6.5).

The above test results show that, when the resistance measuring apparatus 100 according to the embodiment of the present invention is used, the accuracy and reliability of the sheet resistance measurement of the flexible conductive material (CF) is improved compared to the conventional measurement method.

On the other hand, the resistance measuring apparatus 100 for a conductive material according to a modified example of the present invention, as shown in Figs. 4 and 5, the attachment part 170 and the rotating part 180 in the configuration of the above-described embodiment more can be included.

Here, the attachment part 170 is a component provided on the pressing plate 120 so that the conductive material CF is more flatly spread and adsorbed together with the pressing plate 120 , as shown in FIGS. 4 and 5 . Likewise, it may be configured to include an empty space 172 communicating with the vacuum device 174 and a plurality of intake holes 175 .

The empty space 172 is a component that is formed inside the pressure plate 120 and communicates with the vacuum device 174, and the plurality of intake holes 175 are empty on one surface of the pressure plate 120 that presses the conductive material CF. It is a component formed to communicate with the space (172).

At this time, the vacuum device 174 makes the empty space 172 into a negative pressure state according to the operation control by the controller 140 in a state connected through the above-described controller 140 and the tube 175, and the empty space 172 It induces the suction of air through the plurality of intake holes 175 in communication with the.

Due to this, the flexible conductive material (CF) does not become more wrinkled with pressure by the pressing plate 120 and maintains a flat state, and the sheet resistance or conductivity is measured in a non-contact method, resulting in consistent, reliable and accurate Collateralized measurements can be derived.

The rotating unit 180 is a component that rotates the pressing plate 120 so that the above-described intake hole 175 is positioned upward or downward, respectively, and as shown in FIGS. 4 and 5 , the lifting block 166 . It may be composed of a shaft hole 184 formed in, and a rotation shaft 182 that is formed to protrude from the pressure plate 120 toward the lifting block 166 and is rotatably coupled to the shaft hole 184 .

Due to this rotating part 180, it is possible to rotate the pressure plate 120 so that the intake hole 175 faces upward, and at this time, when the vacuum device 174 is operated, the conductive material CF is moved to the correct position. can be seated accurately.

Then, the pressure plate 120 is rotated so that the intake hole 175 faces downward, and the conductive material CF is pressed to a predetermined pressure through the downward movement of the pressure plate 120 by the pressing unit 160, and then the probe unit A series of measurement processes of successively performing the sheet resistance measurement operation by 130 can be made.

In the foregoing, specific embodiments of the present invention have been described and illustrated, but it is common knowledge in the art that the present invention is not limited to the described embodiments, and that various modifications and variations can be made without departing from the spirit and scope of the present invention. It is self-evident to those who have Accordingly, such modifications or variations should not be individually understood from the spirit or point of view of the present invention, and modified embodiments should be said to belong to the claims of the present invention.

100: resistance measuring device for conductive materials
CF: conductive material 110: table
112: top plate 113: hollow
114: leg G: separation
120: pressure plate 130: probe unit
132: core 134: coil
136: housing 140: control unit
150: lifting unit 152: male thread
154: female thread 160: pressing part
162: pulley 164: belt
166: elevating block 170: attachment part
172: empty space 174: vacuum device
175: tube 176: intake hole
180: rotating part 182: rotating shaft
184: shaft

Claims (6)

A table made of an insulating material on which a flexible conductive material is placed on the upper surface based on the hollow formed through it; a press plate made of an insulating material for pressing the upper surface of the conductive material to be laid flat; a probe unit coupled to the hollow at the bottom of the table to be spaced apart from the conductive material to induce an eddy current on the conductive material and generate a predetermined electrical signal from the eddy current; and a control unit for measuring a sheet resistance value based on the electrical signal generated by being connected to the probe unit,
The press plate is
It is formed in a size that covers the whole of the conductive material,
Further comprising a pressing part installed between the table and the pressing plate to move the pressing plate in the vertical direction and pressing the conductive material with a predetermined pressure,
The pressurizing part,
a pair of pulleys disposed vertically and rotated by the rotational force of the power unit;
a belt arranged to span the pair of pulleys, one side of which moves up and down according to the rotation of the pulleys; and
Resistance measuring device for a conductive material, characterized in that it comprises a lifting block coupled to the press plate in a state of being fixed to one side of the belt to elevate the press plate. According to claim 1,
The resistance measuring device for the conductive material,
Resistance measuring device for a conductive material, characterized in that it further comprises a lifting unit installed between the table and the probe unit to adjust the separation distance to move the probe unit in the vertical direction. delete delete A table made of an insulating material on which a flexible conductive material is placed on the upper surface based on the hollow formed through it; a press plate made of an insulating material for pressing the upper surface of the conductive material to be laid flat; a probe unit coupled to the hollow at the bottom of the table to be spaced apart from the conductive material to induce an eddy current on the conductive material and generate a predetermined electrical signal from the eddy current; and a control unit for measuring a sheet resistance value based on the electrical signal generated by being connected to the probe unit,
It is provided on the pressing plate and further includes an attachment part for adsorbing the conductive material to be flattened,
The attachment part,
an empty space formed inside the pressing plate and communicating with the vacuum device; and a plurality of intake holes formed to communicate with the empty space on one surface of the pressing plate for pressing the conductive material. 6. The method of claim 5,
The resistance measuring device for the conductive material,
Resistance measuring device for a conductive material, characterized in that it further comprises a rotating part for rotating the press plate so that the intake hole is positioned upward or downward, respectively.

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