Measuring instrument, measuring device, and measuring method

Abstract

A measuring instrument (1) measures, with respect to a measurement axis direction (X), the thickness (D) of a coating layer (5B) of an object to be measured (5) in which the coating layer (5B) is formed on a surface (5a) of a base material (5A), the measuring instrument comprising: a first measurement unit (11) that is provided with a first end section (13) having a first end surface (13a) serving as a first measurement reference position, and that electromagnetically measures a first distance (A), with respect to the measurement axis direction (X), between the first end surface (13a) and the surface (5a) of the base material (5A); and a second measurement unit (12) that is provided with a second end section (14) having a second end surface (14a) serving as a second measurement reference position, and that optically measures a second distance (B), with respect to the measurement axis direction (X), between the second end surface (14a) and a surface (5b) of the coating layer (5B). The first end section (13) and the second end section (14) are disposed adjacent to each other in a direction (Y) orthogonal to the measurement axis direction (X).

Description

Measuring equipment, measuring device and measuring method

[0001] The present invention relates to a measuring instrument, a measuring device, and a measuring method.

[0002] A sensor system for measuring the thickness of a coating layer formed on the surface of a substrate as a measurement target is known (see Patent Document 1). This sensor system includes an optical displacement sensor, such as a triangulation-type laser displacement sensor (laser triangulation sensor) or a chromatic confocal displacement sensor, and an eddy-current displacement sensor, with the optical displacement sensor disposed above the coil of the eddy-current displacement sensor. Therefore, in this sensor system, the measurement reference position (measurement reference surface) measured by the optical displacement sensor is disposed above the measurement reference position (measurement reference surface) measured by the eddy-current displacement sensor, and the optical displacement sensor measures the coating layer through the center of the coil of the eddy-current displacement sensor.

[0003] Japanese Patent No. 7203961 Japanese Patent Laid-Open No. 2007-113980

[0004] In the above-mentioned Patent Document 1, the optical displacement sensor is positioned above the coil, so the measurement reference position of the optical displacement sensor is separated from the measurement reference position of the eddy current displacement sensor by at least the height of the coil in the measurement axis direction for measuring the object. This separation of the measurement reference positions makes it difficult to make the measurement axes of the optical displacement sensor and the eddy current displacement sensor parallel to each other, for example, to align them. Furthermore, in the structure of Patent Document 1, the distance between the optical displacement sensor and the object is long, so the fixation state of the optical displacement sensor and the eddy current displacement sensor is easily affected by changes over time or temperature changes in the measurement environment. For example, there is a problem in that the measurement axes of the optical displacement sensor and the eddy current displacement sensor easily become misaligned as the measurement axes tilt relative to the direction perpendicular to the surface of the object. When the measurement axes of the optical displacement sensor and the eddy current displacement sensor tilt, the accuracy of measuring the thickness of the object significantly decreases.

[0005] Furthermore, the measurement range perpendicular to the measurement axis, i.e., the so-called spot diameter, of the above-mentioned optical displacement sensors, such as laser triangulation sensors and chromatic confocal displacement sensors, is generally on the order of several μm to 100 μm. In contrast, the measurement range of an eddy current displacement sensor is on the order of several mm to several tens of mm, which is several hundred times smaller than the measurement range of an optical displacement sensor. This difference in measurement ranges results in low accuracy in measuring the thickness of the object being measured. For example, if irregularities of the order of several μm occur on the surface of the object being measured, a difference occurs between the measurement ranges of the optical displacement sensor and the eddy current displacement sensor relative to the irregularities, significantly reducing the accuracy in measuring the thickness of the object being measured.

[0006] The disclosed technology has been made in consideration of the above, and aims to provide a measuring device that can improve the accuracy of measuring the thickness of an object to be measured.

[0007] One aspect of a measuring instrument disclosed herein is a measuring instrument for measuring the thickness of a coating layer on a surface of a substrate in a measurement axis direction, the measuring instrument including: a first measurement unit having a first end portion with a first end face as a first measurement reference position, and configured to electromagnetically measure a first distance in the measurement axis direction between the first end face and the surface of the substrate; and a second measurement unit having a second end portion with a second end face as a second measurement reference position, and configured to optically measure a second distance in the measurement axis direction between the second end face and the surface of the coating layer. The first end portion and the second end portion are arranged adjacent to each other in a direction perpendicular to the measurement axis direction.

[0008] According to one aspect of the measuring device disclosed in the present application, it is possible to improve the accuracy of measuring the thickness of an object to be measured.

[0009] FIG. 1 is a perspective view schematically illustrating a measuring instrument of the first embodiment. FIG. 2 is a plan view schematically illustrating a first measuring unit and a second measuring unit in the measuring instrument of the first embodiment, viewed from the first end face and the second end face. FIG. 3 is a perspective view schematically illustrating the measurement ranges of the first measuring unit and the second measuring unit in the measuring instrument of the first embodiment. FIG. 4 is a schematic diagram for explaining the calculation of the thickness of a coating layer in the measuring instrument of the first embodiment. FIG. 5 is a graph for explaining the relationship between the drive frequency of an eddy current displacement sensor in the measuring instrument of the first embodiment and the depth of eddy currents. FIG. 6 is a schematic diagram for explaining a temperature sensor and a temperature adjustment unit in the measuring instrument of the first embodiment. FIG. 7 is a perspective view showing a measuring device including the measuring instrument of the first embodiment. FIG. 8 is a perspective view schematically illustrating main parts of a measuring instrument of the second embodiment. FIG. 9 is a plan view schematically illustrating the first measuring unit and the second measuring unit in the measuring instrument of the second embodiment, viewed from the first end face and the second end face. FIG. 10 is a plan view for explaining main parts of a measuring instrument of the third embodiment. FIG. 11 is a schematic diagram showing the main parts of a measuring device according to the fourth embodiment.

[0010] Hereinafter, embodiments of a measuring device, a measuring apparatus, and a measuring method disclosed in the present application will be described in detail with reference to the drawings. Note that the measuring device, the measuring apparatus, and the measuring method disclosed in the present application are not limited to the following embodiments. [Embodiment 1]

[0011] (Measuring Instrument) Fig. 1 is a perspective view schematically showing the measuring instrument of embodiment 1. Fig. 2 is a plan view schematically showing the first measuring unit and the second measuring unit in the measuring instrument of embodiment 1, as viewed from the first end face and the second end face side.

[0012] As shown in FIG. 1 , the measuring device 1 of the first embodiment measures the thickness of a coating layer 5B in the measurement axis direction X of a measurement object 5, which has a coating layer 5B formed on the surface 5a of a substrate 5A. An example of the measurement object 5 whose thickness is measured by the measuring device 1 of the first embodiment is a battery electrode sheet, and the thickness is the thickness of a coating film of an active material as the coating layer 5B formed on the surface of a metal foil as the substrate 5A. In this case, the thickness of the metal foil is approximately 10 μm to 20 μm, and the thickness of the coating film is approximately 50 μm to 300 μm. Although the coating film of the active material is slightly conductive, its conductivity is approximately six orders of magnitude smaller than that of the metal foil, so the conductivity of the coating film can be ignored in electromagnetic measurements of the metal foil. Furthermore, the coating film is not optically transparent and is formed opaque.

[0013] The object to be measured 5 is not limited to an electrode, and the present invention may be applied to measuring the thickness of a coating layer 5B formed on a substrate 5A having a conductivity value six orders of magnitude higher than that of the coating layer 5B. For example, the present invention may be applied to measuring the thickness of a coating film formed on the surface of a steel plate.

[0014] 1 and 2 , the measuring device 1 of the first embodiment includes a first measurement unit 11 having a first end portion 13 with a first end face 13a as a first measurement reference position, which electromagnetically measures a first distance A in the measurement axis direction X between the first end face 13a and the surface (top surface) 5a of the substrate 5A, and a second measurement unit 12 having a second end portion 14 with a second end face 14a as a second measurement reference position, which optically measures a second distance B in the measurement axis direction X between the second end face 14a and the surface (top surface) 5b of the coating layer 5B. That is, the measuring device 1 includes the first measurement unit 11 and the second measurement unit 12, which use different measurement methods, and detects the thickness of the coating layer 5B based on a calculation of the first distance A, which is a measurement value measured by the first measurement unit 11, and the second distance B, which is a measurement value measured by the second measurement unit 12. The measurement axis direction X is parallel to the thickness direction of the object 5 and perpendicular to the surface 5a of the substrate 5A and the surface 5b of the coating layer 5B.

[0015] The first measuring unit 11 includes an eddy current displacement sensor 16. The eddy current displacement sensor 16 of the first measuring unit 11 includes a coil 16a that generates a magnetic field toward the surface 5a of the substrate 5A, a high-frequency oscillation circuit 16b that passes a high-frequency current through the coil 16a, and a first detection circuit 16c that detects the first distance A based on the eddy current.

[0016] The second measurement unit 12 includes an optical fiber displacement sensor 17. The optical fiber displacement sensor 17 of the second measurement unit 12 includes a plurality of light-emitting optical fibers 17a that emit detection light for detecting the thickness of the coating layer 5B, a plurality of light-receiving optical fibers 17b that receive the detection light reflected by the surface 5b of the coating layer 5B, a pipe member 17c that bundles the plurality of light-emitting optical fibers 17a and the plurality of light-receiving optical fibers 17b, and a second detection circuit 17d that detects the second distance B based on the detection light. As shown in FIG. 2 , the plurality of light-emitting optical fibers 17a and the plurality of light-receiving optical fibers 17b are arranged alternately at intervals around the measurement axis on the second end face 14a. Note that FIG. 2 does not illustrate some of the plurality of light-emitting optical fibers 17a and some of the plurality of light-receiving optical fibers 17b.

[0017] The high-frequency oscillation circuit 16b and first detection circuit 16c of the eddy current displacement sensor 16 and the second detection circuit 17d of the optical fiber displacement sensor 17 are electrically connected to a control circuit 18 including an arithmetic element that performs various types of signal processing, and the control circuit 18 controls the measurement operations of the eddy current displacement sensor 16 and the optical fiber displacement sensor 17. The high-frequency oscillation circuit 16b, the first detection circuit 16c, the second detection circuit 17d, and the control circuit 18 may be provided in the measuring device 1, or may be provided in a control device (not shown) electrically connected to the measuring device 1.

[0018] In this way, the second measurement unit 12 is provided with the optical fiber displacement sensor 17 in which a plurality of light-emitting optical fibers 17a and a plurality of light-receiving optical fibers 17b are arranged on the second end face 14a, and thereby the second measurement range R2 of the second measurement unit 12 can be widened to be equivalent to the first measurement range R1 of the first measurement unit 11 described below. Therefore, in the direction Y perpendicular to the measurement axis direction X described below, it is possible to prevent a difference from occurring between the first measurement range R1 measured by the first measurement unit 11 and the second measurement range R2 measured by the second measurement unit 12, thereby improving the measurement accuracy of the thickness of the coating layer 5B.

[0019] In the first embodiment, the first end 13 of the first measuring unit 11 and the second end 14 of the second measuring unit 12 are arranged adjacent to each other in a direction Y perpendicular to the measurement axis direction X. The direction Y perpendicular to the measurement axis direction X is any direction on a plane along the surface of the object to be measured 5. In other words, the first end 13 and the second end 14 are arranged to be in contact with each other on the same plane along the surface 5 b of the coating layer 5B and the surface 5 a of the substrate 5A. For example, the cylindrical second end 14 is arranged in contact with the outer periphery of the cylindrical first end 13 along the circumferential direction. Therefore, in the first embodiment, the first measurement axis M1 of the first measuring unit 11 and the second measurement axis M2 of the second measuring unit 12 are configured to coincide. That is, the coils 16 a of the optical fiber displacement sensor 17 and the eddy current displacement sensor 16 are provided on the outer periphery of the pipe member 17 c so that the measurement axes M1 and M2 coincide. For example, the coil 16a is wound around the outer periphery of the pipe member 17c, so that the eddy current displacement sensor 16 and the optical fiber displacement sensor 17 are firmly fixed together.

[0020] This prevents the fixed state of the eddy current displacement sensor 16 and the optical fiber displacement sensor 17 from fluctuating over time or due to temperature changes in the measurement environment, making it difficult for the relative position of the first end face 13a and the second end face 14a to fluctuate, thereby suppressing, for example, fluctuations such as the tilt of the measurement axes M1 and M2 with respect to the direction perpendicular to the surface 5b of the measurement object 5. As a result, errors in the first distance A measured by the first measuring unit 11 and the second distance B measured by the second measuring unit 12 are prevented, improving the measurement accuracy of the thickness D of the coating layer 5B.

[0021] Furthermore, the first end face 13a of the first measurement unit 11 and the second end face 14a of the second measurement unit 12 are disposed close to each other in the measurement axis direction X. In the first embodiment, as an example, the second end face 14a of the second measurement unit 12 protrudes downward in the measurement axis direction X (toward the measurement object 5) from the first end face 13a of the first measurement unit 11. The first measurement unit 11 and the second measurement unit 12 are fixed so that the distance C between the first end face 13a and the second end face 14a in the measurement axis direction X is approximately 10 mm or less. This prevents a difference in size between the first measurement range R1 of the first measurement unit 11 and the second measurement range R2 of the second measurement unit 12, thereby improving the measurement accuracy of the thickness D of the coating layer 5B.

[0022] In the first embodiment, the second end face 14a of the second measurement unit 12 protrudes downward in the measurement axis direction X from the first end face 13a of the first measurement unit 11, but the position of the second end face 14a in the measurement axis direction X is not limited. Although not shown, the second end face 14a of the second measurement unit 12 may be recessed upward from the center of the first end face 13a so as to be located higher in the measurement axis direction X than the first end face 13a of the first measurement unit 11. Alternatively, the second end face 14a of the second measurement unit 12 may be positioned at the same position in the measurement axis direction X as the first end face 13a of the first measurement unit 11, i.e., on the same plane.

[0023] (Measurement Ranges of First and Second Measurement Units) FIG. 3 is a perspective view schematically showing the measurement ranges R1, R2 of the first and second measurement units 11, 12 in the measurement device 1 of the first embodiment.

[0024] 3, in the first embodiment, for example, a circular second measurement range R2 irradiated with the detection light of the optical fiber displacement sensor 17 is positioned within a circular first measurement range R1 through which the eddy current E of the eddy current displacement sensor 16 passes, and the first measurement range R1 and the second measurement range R2 are configured to roughly coincide with each other on the surface 5b of the coating layer 5B. This prevents errors in measurement values ​​due to the difference in position between the first measurement range R1 of the first measurement unit 11 and the second measurement range R2 of the second measurement unit 12, thereby improving the measurement accuracy of the thickness of the coating layer 5B.

[0025] In the first embodiment, the first measurement range R1 measured by the first measurement unit 11 is configured to be within 100 times, and more preferably within 10 times, the second measurement range R2 measured by the second measurement unit 12, which prevents the difference in size between the first measurement range R1 of the first measurement unit 11 and the second measurement range R2 of the second measurement unit 12, thereby improving the accuracy of measuring the thickness of the coating layer 5B.

[0026] (Calculation of Coating Layer Thickness) FIG. 4 is a schematic diagram for explaining the calculation of the thickness of the coating layer 5B in the measuring device 1 of embodiment 1. As shown in FIGS. 1 and 4, A denotes the first distance in the measurement axis direction X between the first end face 13a of the first measuring unit 11 and the surface 5a of the substrate 5A, B denotes the second distance in the measurement axis direction X between the second end face 14a of the second measuring unit 12 and the surface (upper surface) 5b of the coating layer 5B, and C denotes the distance in the measurement axis direction X between the first end face 13a and the second end face 14a located below the first end face 13a (toward the measurement object 5). The distance C is a constant dimension in the structure of the measuring device 1. In this case, the thickness D of the coating layer 5B can be calculated by, for example, D = A - (B + C) using the control circuit 18.

[0027] Furthermore, when the second end face 14a is located higher than the first end face 13a in the measurement axis direction X, the thickness D of the coating layer 5B can be calculated by D = A - (B - C), where C is the distance in the measurement axis direction X between the first end face 13a and the second end face 14a located higher than the first end face 13a (on the opposite side from the measurement object 5). Similarly, when the first end face 13a and the second end face 14a are located at the same position in the measurement axis direction X, the distance between the first end face 13a and the second end face 14a is "0", and the thickness D of the coating layer 5B can be calculated by D = A - B.

[0028] (Drive Frequency of Eddy Current Displacement Sensor) Figure 5 is a graph illustrating the relationship between the drive frequency of the eddy current displacement sensor 16 in the measuring device 1 of embodiment 1 and the depth of the eddy current. In Figure 5, the vertical axis represents the depth [mm] of the eddy current in the measurement axis direction X, i.e., the thickness direction of the object to be measured 5, and the horizontal axis represents the drive frequency [Hz] of the high-frequency current applied to the coil 16a of the eddy current displacement sensor 16. In Figure 5, the solid line represents the change when the object to be measured 5 is aluminum, and the dashed line represents the change when the object to be measured 5 is copper. The depth of the eddy current here refers to the depth position from the surface 5a of the object to be measured 5 (surface 5a of the substrate 5A) at which the magnitude of the eddy current is 1 / e, i.e., approximately 36.8%, of the magnitude at the surface 5a.

[0029] As shown in Figure 5, the depth position of the eddy current tends to decrease as the drive frequency increases. When the depth position of the eddy current in the measurement axis direction X is not located inside the substrate 5A (within the thickness range of the substrate 5A) but passes through the substrate 5A and becomes a position outside the substrate 5A, it becomes difficult for the eddy current displacement sensor 16 to accurately measure the thickness. For this reason, in embodiment 1, the drive frequency is appropriately controlled by the control circuit 18 so that the depth position of the eddy current measured by the eddy current displacement sensor 16 is located within the thickness range of the substrate 5A. In this way, the measuring device 1 can appropriately measure the first distance A to the surface 5a of the substrate 5A, which is 20 μm or less, by the control circuit 18 controlling the depth position of the eddy current measured by the eddy current displacement sensor 16.

[0030] Furthermore, for example, if the thickness of the substrate 5A is 10 μm or less and it is difficult to control the eddy current depth position of the eddy current displacement sensor 16 so that it is located within the thickness range of the substrate 5A, the substrate 5A can be placed on a mounting member 54 (see FIG. 7 ), such as a metal plate, having a conductivity similar to that of the substrate 5A for measurement, and the mounting member 54 on which the substrate 5A is placed can be treated as part of the substrate 5A, making it possible to properly measure the first distance A to the surface 5 a of the substrate 5A. Here, "similar conductivity" refers to a conductivity in which the ratio of the conductivity of the mounting member 54 to the conductivity of the substrate 5A is approximately 0.9 or more and 1.1 or less.

[0031] (Temperature Sensor and Temperature Adjustment Unit) Figure 6 is a schematic diagram for explaining the temperature sensor and temperature adjustment unit in the measuring device 1 of embodiment 1. As shown in Figure 6, the measuring device 1 of embodiment 1 includes a first temperature sensor 21 that detects the temperature of the first measuring unit 11, a second temperature sensor 22 that detects the temperature of the second measuring unit 12, a first temperature adjustment unit 23 that heats or cools the first measuring unit 11 based on the detection result of the first temperature sensor 21, and a second temperature adjustment unit 24 that heats or cools the second measuring unit 12 based on the detection result of the second temperature sensor 22.

[0032] The first temperature sensor 21 and the first temperature adjustment unit 23 are electrically connected to the control circuit 18 and are arranged, for example, on the outer periphery of the coil 16a at the first end 13 of the first measuring unit 11. Similarly, the second temperature sensor 22 and the second temperature adjustment unit 24 are electrically connected to the control circuit 18 and are arranged, for example, on the outer periphery of the pipe member 17c at the second end 14 of the second measuring unit 12. The first temperature adjustment unit 23 and the second temperature adjustment unit 24 have, for example, a heating element (heater) for heating and a Peltier element for cooling, but a fluid circuit in which a temperature adjustment fluid circulates may also be used.

[0033] In this way, in the measuring device 1, the first temperature adjustment unit 23 adjusts the first measuring unit 11 to a predetermined temperature, and the second temperature adjustment unit 24 adjusts the second measuring unit 12 to a predetermined temperature. This prevents fluctuations in the first distance A measured by the first measuring unit 11 and the second distance B measured by the second measuring unit 12 due to temperature changes during use of the first measuring unit 11 and the second measuring unit 12, or temperature changes in the measurement environment in which the measuring device 1 is used.

[0034] Alternatively, the measuring device 1 may not include the first temperature adjustment unit 23 and the second temperature adjustment unit 24, and the control circuit 18 may correct the first distance A measured by the first measuring unit 11 based on the detection result of the first temperature sensor 21, and correct the second distance B measured by the second measuring unit 12 based on the detection result of the second temperature sensor 22. This makes it possible to appropriately ensure the measurement accuracy of the first distance A measured by the first measuring unit 11 and the measurement accuracy of the second distance B measured by the second measuring unit 12, even when the temperature changes described above occur.

[0035] (Measuring Apparatus) Fig. 7 is a perspective view showing a measuring apparatus including the measuring apparatus 1 of embodiment 1. As shown in Fig. 7, the measuring apparatus 51 of embodiment 1 includes the above-described measuring apparatus 1, a support unit 52 that movably supports the measuring apparatus 1, a drive unit 53 that moves the measuring apparatus 1 in a direction Y perpendicular to the measurement axis direction X relative to the measurement object 5, a mounting member 54 on which the measurement object 5 is placed, and a control unit 55 that controls the measuring apparatus 1 and the drive unit 53.

[0036] Although not shown, the measuring device 51 of the embodiment is used in the manufacturing process of a battery electrode sheet, and is installed on a transport path of the electrode sheet between a supply unit having a supply roll that supplies a long metal foil, a coating unit that applies an active material to the metal foil, a drying unit that dries the active material, and a winding unit having a winding roll that winds up the transported electrode sheet. The measuring device 51 measures the thickness D of the coating layer 5B of the measurement object 5, which is an electrode sheet transported along the transport path.

[0037] The driving unit 53 has a guide portion 53 a formed on the support portion 52 and a driving mechanism (not shown) that moves the measuring device 1 along the guide portion 53 a. The measuring device 51 performs measurement, for example, while moving the measuring device 1 relative to the measurement object 5 by the driving unit 53.

[0038] The control unit 55 is electrically connected to the first measuring unit 11 and the second measuring unit 12 and the drive unit 53 of the measuring device 1 via wiring or the like. The control unit 55 includes the high-frequency oscillation circuit 16b, the first detection circuit 16c, the second detection circuit 17d, the control circuit 18, etc., of the measuring device 1 described above. The control unit 55 controls the first measuring unit 11 and the second measuring unit 12 to simultaneously measure the measurement object 5 being transported in the direction Y perpendicular to the measurement axis direction X relative to the measuring device 1. This prevents the first measurement range R1 of the first measuring unit 11 and the second measurement range R2 of the second measuring unit 12 from separating when the measuring device 51 measures the measurement object 5 being transported relative to the measuring device 1, thereby ensuring appropriate measurement accuracy of the measurement object 5.

[0039] The mounting member 54 is, for example, a transport roller that supports the measurement object 5 that is supplied to and transported by the measuring device 51, and the transport roller is rotatably provided on the support part 52. The measuring device 51 of the first embodiment is not limited to measuring the thickness of the transported measurement object 5, and the measuring device 51 may be provided with a mounting table (not shown) on which the measurement object 5 is placed, instead of the transport roller as the mounting member 54, or may be provided with a transport roller and a mounting table.

[0040] Furthermore, for example, when measuring at a position where the measurement axes M1, M2 of the measuring instrument 1 pass through the mounting member 54, even if the depth position of the eddy current in the measurement axis direction X in the eddy current displacement sensor 16 passes through the substrate 5A beyond the thickness of the substrate 5A, the mounting members 54, such as the conveying rollers and mounting table, have conductivity similar to that of the substrate 5A, so they can be treated as part of the substrate 5A, and the eddy current displacement sensor 16 can properly measure the first distance A between the surface 5a and the first end face 13a of the substrate 5A.

[0041] The measuring device 51 is not limited to a configuration including the measuring device 1 of the first embodiment, but may include measuring devices 2 and 3 of other embodiments described later.

[0042] (Measurement Method) In the measurement method of the first embodiment, the above-described measuring instrument 1 or measuring device 51 is used to measure the thickness D of the coating layer 5B formed on the surface 5a of the substrate 5A of the measurement object 5. The measurement object 5 is an electrode sheet of a battery, and for example, the substrate 5A is a metal foil and the coating layer 5B is an active material.

[0043] Effect of First Embodiment As described above, the measuring device 1 in the first embodiment includes a first measurement unit 11 provided with a first end portion 13 having a first end face 13 a as a first measurement reference position and electromagnetically measuring a first distance A in the measurement axis direction X between the first end face 13 a and the surface 5 a of the substrate 5A, and a second measurement unit 12 provided with a second end portion 14 having a second end face 14 a as a second measurement reference position and optically measuring a second distance B in the measurement axis direction X between the second end face 14 a and the surface 5 b of the coating layer 5B, the first end portion 13 and the second end portion 14 being arranged adjacent to each other in a direction Y perpendicular to the measurement axis direction X. This reduces the difference in size and position between the first measurement range R1 measured by the first measurement unit 11 and the second measurement range R2 measured by the second measurement unit 12, thereby improving the measurement accuracy of the thickness of the coating layer 5B.

[0044] Furthermore, in the measuring device 1 of the first embodiment, the first end face 13a of the first measuring unit 11 and the second end face 14a of the second measuring unit 12 are disposed close to each other in the measurement axis direction X. This reduces the difference in size between the first measurement range R1 of the first measuring unit 11 and the second measurement range R2 of the second measuring unit 12, thereby improving the measurement accuracy of the thickness D of the coating layer 5B.

[0045] Furthermore, in the measuring device 1 of the first embodiment, the first measurement range R1 measured by the first measurement unit 11 is within 100 times, and more preferably within 10 times, the second measurement range R2 measured by the second measurement unit 12. This prevents a difference in size between the first measurement range R1 of the first measurement unit 11 and the second measurement range R2 of the second measurement unit 12, thereby improving the measurement accuracy of the thickness of the coating layer 5B.

[0046] Furthermore, in the measuring device 1 of Embodiment 1, the coil 16a of the eddy current displacement sensor 16 and the optical fiber displacement sensor 17 is provided on the outer periphery of the pipe member 17c so that the measurement axes M1 and M2 of the eddy current displacement sensor 16 and the optical fiber displacement sensor 17 coincide with each other. This firmly fixes the eddy current displacement sensor 16 and the optical fiber displacement sensor 17, thereby preventing fluctuations in the relative position between the first end face 13a and the second end face 14a due to changes in the fixation state over time or changes in the temperature of the measurement environment. As a result, errors in the first distance A measured by the first measuring unit 11 and the second distance B measured by the second measuring unit 12 are reduced, improving the measurement accuracy of the thickness D of the coating layer 5B.

[0047] Furthermore, the measuring device 1 in the first embodiment includes, for example, a first temperature sensor 21 that detects the temperature of the first measuring unit 11, and a first temperature adjustment unit 23 that is provided in the first measuring unit 11 and heats or cools the first measuring unit 11 based on the detection result of the first temperature sensor 21. This makes it possible to prevent fluctuations in the first distance A measured by the first measuring unit 11 and the second distance B measured by the second measuring unit 12 due to temperature changes during use of the first measuring unit 11 and the second measuring unit 12, or temperature changes in the measurement environment in which the measuring device 1 is used.

[0048] Furthermore, the measuring device 1 in the first embodiment includes, for example, a first temperature sensor 21 that detects the temperature of the first measuring unit 11, and a control circuit 18 that corrects the first distance A measured by the first measuring unit 11 based on the detection result of the first temperature sensor 21. This makes it possible to appropriately ensure the measurement accuracy of the first distance A measured by the first measuring unit 11 even when a temperature change occurs in the first measuring unit 11 or the measurement environment.

[0049] Another embodiment will be described below with reference to the drawings. In this embodiment, parts having the same functions as those in the first embodiment and components identical to those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment, and descriptions thereof will be omitted. [Embodiment 2]

[0050] Fig. 8 is a perspective view schematically showing the main parts of the measuring device of embodiment 2. Fig. 9 is a plan view schematically showing the first measuring unit 11 and the second measuring unit 12 of the measuring device of embodiment 2, as viewed from the first end face 13a and the second end face 14a side. Note that Fig. 9 omits illustration of some of the multiple light-emitting optical fibers 17a and some of the multiple light-receiving optical fibers 17b in the optical fiber displacement sensor 17.

[0051] 8 and 9, the measuring device 2 of the second embodiment includes a plurality of optical fiber displacement sensors 17 as a plurality of second measuring units 12, and a plurality of pipe members 17c are arranged on the outer peripheral surface of the coil 16a of the eddy current displacement sensor 16 at intervals in the circumferential direction of the outer peripheral surface. Thus, in the measuring device 2 of the second embodiment, as in the first embodiment, the first end 13 of the first measuring unit 11 and the second end 14 of the second measuring unit 12 are arranged adjacent to each other in the direction Y perpendicular to the measurement axis direction X. The second end faces 14a of the three optical fiber displacement sensors 17 are aligned with respect to the measurement axis direction X so as to be located on the same plane. Furthermore, the second measurement axis M2 of each optical fiber displacement sensor 17 is arranged parallel to the first measurement axis M1 of the eddy current displacement sensor 16.

[0052] In the second embodiment, as in the first embodiment, the distance C between the first end face 13a and the second end face 14a in the measurement axis direction X is 10 mm or less, and the first measurement range R1 of the first measurement unit 11 is within 100 times, and more preferably within 10 times, the measurement ranges R2 of the multiple second measurement units 12. In the second embodiment, as shown in FIG. 8 , the first measurement range R1 of the eddy current displacement sensor 16 is located at the center where the second measurement ranges R2 of the three optical fiber displacement sensors 17 are concentrated, and the first measurement range R1 is configured to overlap with the three second measurement ranges R2. By positioning the measurement ranges R1 and R2 close to each other in this manner, errors in measurement values ​​due to differences in the positions of the measurement ranges R1 and R2 of the first measurement unit 11 and the second measurement unit 12 are avoided, thereby improving the measurement accuracy of the thickness D of the coating layer 5B.

[0053] In the measuring device 2 of the second embodiment, for example, by correcting the second distance B based on the respective measured values ​​measured by the three optical fiber displacement sensors 17, it is possible to improve the measurement accuracy of the second distance B and therefore the measurement accuracy of the thickness D of the coating layer 5B. For example, in the measuring device 2, the control circuit 18 calculates the inclination of the second end face 14a of the second measuring unit 12 with respect to the direction perpendicular to the thickness direction of the coating layer 5B based on the respective measured values ​​measured by the three optical fiber displacement sensors 17, and corrects the second distance B based on this calculated value.

[0054] As described above, according to the measuring device 2 of the second embodiment, by providing three optical fiber displacement sensors 17 as the plurality of second measuring units 12, it is possible to correct the second distance B in accordance with the inclination of the second end face 14 a of the second measuring unit 12, thereby improving the measurement accuracy of the thickness D of the coating layer 5B.

[0055] Fig. 10 is a plan view for explaining the main parts of the measuring device of embodiment 3. Note that Fig. 10 omits illustration of some of the plurality of light-emitting optical fibers 17a and some of the plurality of light-receiving optical fibers 17b in the optical fiber displacement sensor 17.

[0056] 10 , the measuring device 3 of the third embodiment includes a plurality of eddy current displacement sensors 16 as a plurality of first measuring units 11, and a pipe member 17c of the optical fiber displacement sensor 17 is sandwiched between the outer peripheries of a plurality of coils 16a. As a result, in the measuring device 3 of the third embodiment, as in the first and second embodiments, the first end 13 of the first measuring unit 11 and the second end 14 of the second measuring unit 12 are arranged adjacent to each other in the direction Y perpendicular to the measurement axis direction X. The first end faces 13a of the two eddy current displacement sensors 16 are aligned with respect to the measurement axis direction X so as to be located on the same plane. Furthermore, the first measurement axis M1 of each eddy current displacement sensor 16 is arranged parallel to the second measurement axis M2 of the optical fiber displacement sensor 17.

[0057] In the third embodiment, as in the first embodiment, the distance C between the first end face 13a and the second end face 14a in the measurement axis direction X is 10 mm or less, and the first measurement range R1 of each of the multiple first measurement units 11 is within 100 times, and more preferably within 10 times, the measurement range R2 of the second measurement unit 12. In the third embodiment, the second measurement range R2 of the optical fiber displacement sensor 17 is located in the center of the first measurement ranges R1 of the two eddy current displacement sensors 16, and the second measurement range R2 is configured to overlap with the two first measurement ranges R1. By positioning the measurement ranges R1 and R2 close to each other in this manner, errors in measurement values ​​due to differences in the positions of the measurement ranges of the first measurement unit 11 and the second measurement unit 12 are avoided, thereby improving the measurement accuracy of the thickness D of the coating layer 5B.

[0058] In the measuring device 3 of embodiment 3, for example, by correcting the first distance A based on the measured values ​​measured by the two eddy current displacement sensors 16, it is possible to improve the measurement accuracy of the first distance A and thereby improve the measurement accuracy of the thickness D of the coating layer 5B. For example, in the measuring device 3, the control circuit 18 calculates the inclination of the first end face 13a of the first measuring unit 11 with respect to the direction perpendicular to the thickness direction of the substrate 5A based on the measured values ​​measured by the two eddy current displacement sensors 16, and corrects the first distance A based on this calculated value.

[0059] Although not shown, the first measuring unit 11 may use a combination of the eddy current displacement sensor 16 and a capacitance displacement sensor (see embodiment 4), which will be described later. In embodiments 2 and 3, as in embodiment 1, the temperatures of the first measuring unit 11 and the second measuring unit 12 may be adjusted by the temperature sensors 21 and 22 and the temperature adjustment units 23 and 24. Also in embodiments 2 and 3, as in embodiment 1, the first distance A measured by the first measuring unit 11 and the second distance B measured by the second measuring unit 12 may be corrected by the control circuit 18 based on the detection results of the temperature sensors 21 and 22.

[0060] (Effects of embodiment 3) As described above, according to the measuring device 3 of embodiment 3, by providing two eddy current displacement sensors 16 as the multiple first measuring units 11, it becomes possible to correct the first distance A according to the inclination of the first end face 13a of the first measuring unit 11, thereby improving the measurement accuracy of the thickness D of the coating layer 5B.

[0061] Furthermore, as a measuring instrument, although not shown, structures in which the coil 16a of the eddy current displacement sensor 16 is provided on the outer periphery of the pipe member 17c of the optical fiber displacement sensor 17, as in the measuring instrument 1 of embodiment 1, may be arranged adjacent to each other in the direction Y perpendicular to the measurement axis direction X. This measuring instrument, like embodiments 2 and 3, can correct the first distance A and the second distance B by including multiple first measuring units 11 and multiple second measuring units 12. Furthermore, at least two of the measuring instruments 1 to 3 of embodiments 1 to 3 may be combined, and measurement accuracy can be improved by performing corrections similar to those of embodiments 2 and 3. While embodiments 2 and 3 include multiple measuring units, either the first measuring unit 11 or the second measuring unit 12, the first measuring unit 11 may include multiple eddy current displacement sensors 16, and the second measuring unit 12 may include multiple optical fiber displacement sensors 17, achieving the same effects as those of embodiments 2 and 3. [Embodiment 4]

[0062] Fig. 11 is a schematic diagram showing the main parts of a measuring device of embodiment 4. As shown in Fig. 11, the measuring device 4 of embodiment 4 includes a capacitance displacement sensor 19 as a first measuring unit 11, instead of the eddy current displacement sensor 16 in embodiment 1. The capacitance displacement sensor 19 has a flat electrode plate 19a disposed opposite the measurement object 5. An optical fiber displacement sensor 17 as a second measuring unit 12 is provided so as to pass through the inside of the capacitance displacement sensor 19 and penetrate the electrode plate 19a.

[0063] The electrode plate 19a of the capacitance displacement sensor 19 is disposed adjacent to the second end face 14a of the second measurement unit 12, which is constituted by the optical fiber displacement sensor 17, in the direction Y perpendicular to the measurement axis direction X. In this case, the surface of the electrode plate 19a facing the object 5 corresponds to the first end face 13a as the first measurement reference position. Even when the electrode plate 19a is disposed facing the surface 5b of the coating layer 5B, the position of the surface 5a of the substrate 5A can be measured by appropriately correcting fluctuations associated with the conductivity of the coating layer 5B using the control circuit 18. Also in the fourth embodiment, as in the first embodiment, the distance C between the first end face 13a and the second end face 14a in the measurement axis direction X is 10 mm or less, and the first measurement range R1 of the first measurement unit 11 is within 100 times, and more preferably within 10 times, the measurement ranges R2 of the second measurement units 12.

[0064] (Effects of Embodiment 4) Even when the eddy current displacement sensor 16 in Embodiment 1 is replaced with a capacitance displacement sensor 19, as in the measuring instrument 4 of Embodiment 4 described above, the first end 13 and the second end 14 are arranged adjacent to each other in the direction Y perpendicular to the measurement axis direction X, as in Embodiment 1, thereby reducing the difference in size and position between the first measurement range R1 of the first measuring unit 11 and the second measurement range R2 of the second measuring unit 12, and improving the measurement accuracy of the thickness of the coating layer 5B.

[0065] (Others) Some examples of combinations of the disclosed technical features are described below.

[0066] (1) A measuring instrument for measuring the thickness of a coating layer formed on the surface of a substrate in a measurement axis direction, the measuring instrument comprising: a first measuring unit having a first end portion with a first end face as a first measurement reference position, and electromagnetically measuring a first distance in the measurement axis direction between the first end face and the surface of the substrate; and a second measuring unit having a second end portion with a second end face as a second measurement reference position, and optically measuring a second distance in the measurement axis direction between the second end face and the surface of the coating layer, the first end portion and the second end portion being arranged adjacent to each other in a direction perpendicular to the measurement axis direction.

[0067] (2) The measuring instrument according to (1), wherein the distance between the first end face and the second end face in the measurement axis direction is 10 mm or less.

[0068] (3) The measuring device according to (1) or (2) above, wherein the first measurement range measured by the first measurement unit is within 100 times the second measurement range measured by the second measurement unit.

[0069] (4) The measuring device according to any one of (1) to (3) above, comprising a plurality of at least one of the first measuring section and the second measuring section.

[0070] (5) A measuring instrument described in any one of (1) to (4) above, wherein the first measuring unit includes an eddy current displacement sensor having a coil that generates a magnetic field, and the second measuring unit includes an optical fiber displacement sensor having a plurality of optical fibers that emit and receive detection light and a pipe member that bundles the plurality of optical fibers.

[0071] (6) The measuring device according to any one of (1) to (4) above, wherein the first measuring unit includes a capacitance displacement sensor and the second measuring unit includes an optical fiber displacement sensor.

[0072] (7) The measuring instrument according to (5) above, wherein the coils of the eddy current displacement sensor and the optical fiber displacement sensor are provided on the outer periphery of the pipe member so that their measurement axes coincide.

[0073] (8) The measuring instrument according to (5) above, comprising a plurality of the optical fiber displacement sensors, and a plurality of the pipe members arranged on the outer peripheral surface of the coil in the circumferential direction of the outer peripheral surface.

[0074] (9) The measuring instrument according to (5) above, comprising a plurality of the eddy current displacement sensors, the pipe member being sandwiched between the outer peripheries of the plurality of coils.

[0075] (10) A measuring instrument described in any one of (1) to (9) above, further comprising a temperature sensor that detects the temperature of at least one of the first measuring unit and the second measuring unit, and a temperature control unit that is provided in at least one of the measuring units and heats or cools the at least one of the measuring units based on the detection result of the temperature sensor.

[0076] (11) A measuring instrument described in any one of (1) to (9) above, further comprising a temperature sensor that detects the temperature of at least one of the first measuring unit and the second measuring unit, and a control circuit that corrects the distance measured by at least one of the measuring units based on the detection result of the temperature sensor.

[0077] (12) A measuring apparatus comprising: a measuring instrument according to any one of (1) to (11) above; a support unit that movably supports the measuring instrument; a drive unit that moves the measuring instrument in a direction perpendicular to the measurement axis direction relative to the object to be measured; and a control unit that controls the measuring instrument and the drive unit.

[0078] (13) The measuring device described in (12) above, wherein the control unit controls the first measuring unit and the second measuring unit to simultaneously measure the object to be measured, which is transported in a direction perpendicular to the measurement axis direction relative to the measuring instrument.

[0079] (14) The measuring device according to (12) or (13) above, further comprising a mounting member on which the object to be measured is placed, wherein the ratio of the conductivity of the mounting member to the conductivity of the base material is 0.9 or more and 1.1 or less.

[0080] (15) A measurement method for measuring the thickness of a coating layer formed on the surface of a substrate in a measurement axis direction, the measurement method using a measuring device that has a first measurement unit having a first end face as a first measurement reference position and that electromagnetically measures a first distance in the measurement axis direction between the first end face and the surface of the substrate, and a second measurement unit having a second end face as a second measurement reference position and that optically measures a second distance in the measurement axis direction between the second end face and the surface of the coating layer, the measuring device being arranged adjacent to each other in a direction perpendicular to the measurement axis direction.

[0081] (16) The measurement method according to (15) above, wherein the substrate is a metal foil and the coating layer is an active substance.

[0082] 1, 2, 3, 4 Measuring instrument 5 Measurement object 5A Substrate 5a Surface 5B Coating layer 5b Surface 11 First measuring unit 12 Second measuring unit 13 First end 13a First end face 14 Second end 14a Second end face 16 Eddy current displacement sensor 16a Coil 17 Optical fiber displacement sensor 17a Light-emitting optical fiber (optical fiber) 17b Light-receiving optical fiber (optical fiber) 17c Pipe member 18 Control circuit 19 Capacitive displacement sensor 21 First temperature sensor (temperature sensor) 22 Second temperature sensor (temperature sensor) 23 First temperature adjustment unit (temperature adjustment unit) 24 Second temperature adjustment unit (temperature adjustment unit) 51 Measuring device 52 Support unit 53 Drive unit 54 Placement member 55 Control unit A First distance B Second distance C Spacing D Thickness M1 First measurement axis M2 Second measurement axis R1 First measurement range R2 Second measurement range X Measurement axis direction Y Direction perpendicular to the measurement axis direction

Claims

A measuring instrument for measuring the thickness of a coating layer formed on a surface of a substrate in a measurement axis direction, a first measurement unit that is provided with a first end portion having a first end surface as a first measurement reference position and that electromagnetically measures a first distance in the measurement axis direction between the first end surface and the surface of the substrate; a second measurement unit that is provided with a second end portion having a second end surface as a second measurement reference position, and that optically measures a second distance in the measurement axis direction between the second end surface and the surface of the coating layer; The measuring device, wherein the first end and the second end are arranged adjacent to each other in a direction perpendicular to the measurement axis direction. 　 a distance between the first end face and the second end face in the measurement axis direction is 10 mm or less; 10. The measuring device of claim 1. 　 a first measurement range measured by the first measurement unit is within 100 times the second measurement range measured by the second measurement unit; 3. The measuring device of claim 2. 　 The measuring device includes a plurality of at least one of the first measuring unit and the second measuring unit, 10. The measuring device of claim 1. 　 the first measurement unit includes an eddy current displacement sensor having a coil that generates a magnetic field, the second measurement unit includes an optical fiber displacement sensor having a plurality of optical fibers that emit and receive detection light, and a pipe member that bundles the plurality of optical fibers; 10. The measuring device of claim 1. 　 the first measurement unit includes a capacitance displacement sensor, the second measurement unit includes an optical fiber displacement sensor; 10. The measuring device of claim 1. 　 the coils of the eddy current displacement sensor and the optical fiber displacement sensor are provided on the outer periphery of the pipe member so that their measurement axes coincide with each other; 6. The measuring device of claim 5. 　 a plurality of the optical fiber displacement sensors; A plurality of the pipe members are arranged on the outer peripheral surface of the coil in the circumferential direction of the outer peripheral surface.

6. The measuring device of claim 5. 　 a plurality of the eddy current displacement sensors; The pipe member is sandwiched and disposed between the outer peripheries of the plurality of coils.

6. The measuring device of claim 5. 　 a temperature sensor for detecting a temperature of at least one of the first measurement unit and the second measurement unit; a temperature adjusting unit provided in the at least one measuring unit and configured to heat or cool the at least one measuring unit based on a detection result of the temperature sensor; 10. The measuring device of claim 1. 　 a temperature sensor for detecting a temperature of at least one of the first measurement unit and the second measurement unit; a control circuit that corrects the distance measured by the at least one measurement unit based on the detection result of the temperature sensor, 10. The measuring device of claim 1. 　 A measuring device according to any one of claims 1 to 11; a support portion that movably supports the measuring device; a drive unit that moves the measuring device in a direction perpendicular to the measurement axis direction relative to the measurement object; a control unit that controls the measuring device and the drive unit, Measuring device. 　 the control unit controls the first measurement unit and the second measurement unit to simultaneously measure the object to be measured, the object being transported in a direction perpendicular to the measurement axis direction relative to the measuring device.

13. The measuring device of claim 12. 　 Further provided is a mounting member on which the measurement object is placed, The ratio of the conductivity of the mounting member to the conductivity of the base material is 0.9 or more and 1.1 or less, 13. The measuring device of claim 12. 　 A measurement method for measuring the thickness of a coating layer formed on a surface of a substrate in a measurement object in a measurement axis direction, comprising: A measurement method using a measuring device in which a first measurement unit is provided with a first end portion having a first end face as a first measurement reference position and electromagnetically measures a first distance in the measurement axis direction between the first end face and the surface of the substrate, and a second measurement unit is provided with a second end portion having a second end face as a second measurement reference position and optically measures a second distance in the measurement axis direction between the second end face and the surface of the coating layer, the second measurement unit being arranged adjacent to each other in a direction perpendicular to the measurement axis direction. 　 The substrate is a metal foil and the coating layer is an active substance. The measurement method according to claim 15.

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