Thickness measuring device

Abstract

To provide a thickness measuring device capable of precisely measuring the thickness of a functional sheet of a coating film formed on a carrier sheet, and a manufacturing device and a manufacturing method of a ceramic green sheet utilizing the thickness measuring device.SOLUTION: A thickness measuring device 1 for measuring the thickness of a coating film 20 formed on a conveyed carrier sheet 10 includes: a first measurement section 1A for acquiring thickness information of the carrier sheet 10 before formation of the coating film 20 by applying light, and acquiring a first position; a second measurement section 1B for acquiring thickness information of the carrier sheet 10 and the coating film 20 after formation of the coating film 20 by applying radiations, and acquiring a second position; and an arithmetic processing section for calculating the thickness of the coating film on the basis of the thickness information of the carrier sheet of the first position and the thickness information in the second position.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a thickness measuring device for measuring the thickness of a functional sheet disposed on a carrier sheet.

Background Art

[0002] Conventionally, in the manufacture of laminated ceramic electronic components such as laminated ceramic capacitors, it is important to control the thickness of the ceramic green sheet. The ceramic green sheet is usually formed by applying a ceramic slurry on a carrier sheet with a predetermined thickness. In the process of applying the ceramic slurry, it is necessary to control the application amount of the ceramic slurry while measuring the thickness of the coating film and adjust it to a predetermined thickness.

[0003] By the way, when measuring the thickness of a ceramic green sheet formed on a carrier sheet, conventionally, a method of measuring using a non-contact type thickness measuring device that does not damage the ceramic green sheet is generally used. The combined value of the thickness of the ceramic green sheet and the thickness of the carrier sheet is measured as the film thickness value, and the thickness of the carrier sheet measured in advance is subtracted from this film thickness value to obtain the thickness of the ceramic green sheet.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in such a measurement method using a non-contact type thickness measuring device, errors caused by positional deviation during measurement occur, and it is not always easy to measure the sheet thickness with high precision.

[0006] In addition, a coating amount measuring device is disclosed in which two types of detectors, namely an X-ray thickness detector and a β-ray thickness detector, are arranged in an integrated type parallel to the flow direction of the carrier sheet, and the coating amount is measured by calculation using the difference in radiation absorption coefficients of each (for example, Patent Document 1).

[0007] However, in such a measuring device using radiation, measurement errors are likely to occur in the thickness of the carrier sheet due to variations in the radiation dose. When the functional sheet, which is a sheet planned to be used as having a specific function such as a coating film, is the measurement target, accurate measurement is required.

[0008] An object of the present invention is to provide a thickness measuring device capable of accurately measuring the thickness of a functional sheet formed on a carrier sheet, and a manufacturing device and a manufacturing method for a ceramic green sheet using this thickness measuring device.

Means for Solving the Problems

[0009] The inventor of the present invention has found that the thickness of the coating film can be accurately measured by providing a first measurement unit that acquires the thickness information of the carrier sheet before the coating film is formed by irradiating light, and a second measurement unit that acquires the thickness information of the carrier sheet and the coating film after the coating film is formed by irradiating radiation, and performing arithmetic processing on the thickness information from the first measurement unit and the thickness information from the second measurement unit, thus completing the present invention.

[0010] That is, the present invention is a thickness measuring device for measuring the thickness of a coating film formed on a carrier sheet to be conveyed, a first measurement unit that acquires the thickness information of the carrier sheet before the coating film is formed by irradiating light, and acquires a first position that is the position where the thickness information of the carrier sheet is acquired, After the coating film is formed, thickness information of the carrier sheet and the coating film is obtained by irradiating radiation, and a second measurement unit that obtains a second position that is the position where the thickness information of the carrier sheet and the coating film is obtained, An arithmetic processing unit that calculates the thickness of the coating film based on the thickness information of the carrier sheet at the first position and the thickness information at the second position within a predetermined range with respect to the first position, A thickness measuring device including:

Advantages of the Invention

[0011] According to the present invention, it is possible to provide a thickness measuring device capable of accurately measuring the thickness of a functional sheet formed on a carrier sheet, and also a manufacturing device and a manufacturing method for a ceramic green sheet using this thickness measuring device.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the thickness measuring device of the present invention will be described, but the present invention is not limited thereto. Also, the drawings may be schematically simplified for explaining the content of the invention, and the ratio of the drawn components or the dimensions between the components may not match the ratio of those dimensions described in the specification. Also, there may be cases where the components described in the specification are omitted in the drawings or the number is omitted in the drawing.

[0014] FIG. 1 is a diagram schematically showing the configuration of a thickness measuring apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram for explaining an apparatus for manufacturing a ceramic green sheet using the thickness measuring apparatus.

[0015] (Thickness Measuring Apparatus) The thickness measuring apparatus 1 measures the thickness of a functional sheet disposed on a carrier sheet 10 being conveyed. For example, a ceramic green sheet used in manufacturing a multilayer ceramic capacitor is formed by applying a ceramic slurry on the carrier sheet 10. By using the thickness measuring apparatus 1, the thickness of the coating film 20 of the ceramic slurry or the ceramic green sheet 21 formed by drying the coating film of the ceramic slurry can be measured. Note that both the coating film 20 of the ceramic slurry and the ceramic green sheet 21 are sheets that are expected to be used as having a specific function of a dielectric layer of a multilayer ceramic capacitor, and are an example of a functional sheet. Also, since the coating film 20 or the ceramic green sheet 21 is disposed on the carrier sheet 10 by coating, the coating is an example of the disposition.

[0016] FIG. 2 shows, as an example of the configuration of an apparatus for continuously manufacturing a ceramic green sheet provided with the thickness measuring apparatus 1, a manufacturing apparatus 40 for a ceramic green sheet. The manufacturing apparatus 40 for a ceramic green sheet includes an unwinding roll 41, a winding roll 42, a first dancer roll 43a, a second dancer roll 43b, first to fourth fixed rolls 44a, 44b, 44c, 44d, the thickness measuring apparatus 1 having a first measuring unit 1A and a second measuring unit 1B, and a coating film forming unit 30.

[0017] The manufacturing apparatus 40 for a ceramic green sheet is an apparatus that applies a ceramic slurry to a carrier sheet 10 unwound from an unwinding roll 41, and winds up the ceramic green sheet 21 formed by drying the applied ceramic slurry together with the carrier sheet 10 with a winding roll 42. The carrier sheet 10 is conveyed from the unwinding roll 41 toward the winding roll 42. The direction in which the carrier sheet 10 is conveyed is defined as the conveyance direction T.

[0018] The manufacturing apparatus 40 for a ceramic green sheet is an apparatus capable of applying a ceramic slurry with an appropriate film thickness by means of a thickness measuring device 1 including a first measuring unit 1A and a second measuring unit 1B.

[0019] In the manufacturing apparatus 40 for a ceramic green sheet, the carrier sheet 10 is a sheet for supporting the ceramic green sheet 21 formed by applying a ceramic slurry and drying the same, and is unwound from the unwinding roll 41. The unwound carrier sheet 10 travels toward the first measuring unit 1A via a first fixed roll 44a, a first dancer roll 43a, and a second fixed roll 44b arranged in order from the conveyance source to the conveyance destination in the conveyance direction T.

[0020] The unwinding roll 41, the first fixed roll 44a, the first dancer roll 43a, and the second fixed roll 44b for conveying the carrier sheet 10 each have a roller shaft (not shown) having a rotation axis. Each roller shaft is a linear rod-shaped member and is arranged parallel to each other. The unwinding roll 41, the first fixed roll 44a, the first dancer roll 43a, and the second fixed roll 44b each rotate about the rotation axis of the roller shaft. Thus, the direction substantially orthogonal to the axial direction of each roller shaft becomes the conveyance direction T. Thereby, the carrier sheet 10 to be conveyed can be stably sent out toward the first measuring unit 1A. Note that the first dancer roll 43a is disposed between the first fixed roll 44a and the second fixed roll 44b, and the tension applied to the carrier sheet 10 is adjusted by adjusting the vertical position of the first dancer roll 43a and the load applied to the first dancer roll 43a. The operation of the first measuring unit 1A will be described later.

[0021] The coating film forming unit 30 is disposed downstream of the first measuring unit 1A in the transport direction T. The coating film forming unit 30 has a coating section equipped with a coating device such as a die coater, and applies a ceramic slurry to the surface of the carrier sheet 10 with a predetermined thickness. The method of applying the ceramic slurry can adopt an on-roll die coater, a vacuum die coater, an off-roll die coater, a slit coater, a curtain coater, a pull-up coater, a knife coater, a cast coater, a reverse roll coater, a blade coater, a screen printing method, etc. according to the thickness of the ceramic green sheet to be formed. The coating film forming unit 30 has a coating section (not shown) and a drying section (not shown). The coating section applies a ceramic slurry to the carrier sheet 10. The drying section dries the ceramic slurry applied to the surface of the carrier sheet 10. As the heat source of the drying means in the drying section, hot air, electric heat, microwave, infrared ray, far-infrared ray, etc. can be used alone or in combination, and it is preferable to perform drying by hot air drying and far-infrared ray alone or in combination.

[0022] The carrier sheet 10 coated with the ceramic slurry by the coating film forming unit 30 is dried in the drying section of the coating film forming unit 30, and the ceramic green sheet 21 is formed.

[0023] The coating film forming unit 30 shown in Fig. 2 includes a coating section for applying a ceramic slurry and, continuously therewith, a drying section for drying the ceramic slurry, and the coating film forming unit 30 is constituted by the coating section and the drying section. However, the present invention is not limited to such a configuration. For example, the coating section and the drying section may be arranged separately, and equipment for performing other processes may be arranged between the coating section and the drying section. Further, the coating film forming unit 30 only needs to have a coating section and may not have a drying section.

[0024] When the objects to be measured by the second measuring unit 1B are the ceramic green sheet 21 and the carrier sheet 10 formed by drying the coating film of the ceramic slurry, the thickness of the ceramic green sheet 21 can be calculated by the thickness measuring device 1. On the other hand, when the objects to be measured by the second measuring unit 1B are the coating film of the ceramic slurry before drying and the carrier sheet 10, the thickness of the coating film of the ceramic slurry can be calculated by the thickness measuring device 1. The operation of the second measuring unit 1B will be described later.

[0025] As described above, the thickness of the coating film 20 that can be calculated by the thickness measuring device 1 includes the thickness of the coating film of the ceramic slurry or the thickness of the ceramic green sheet 21 formed by drying the coating film of the ceramic slurry. In the following embodiments, the coating film 20 may be mainly described as the case of the ceramic green sheet 21 formed by drying the coating film of the ceramic slurry, but the present invention is not limited thereto.

[0026] The carrier sheet 10 advances in the transport direction T together with the formed ceramic green sheet 21, and is wound by the winding roll 42 after passing through the third fixed roll 44c, the second dancer roll 43b, and the fourth fixed roll 44d arranged in order in the transport direction T.

[0027] The third fixed roll 44c, the second dancer roll 43b, the fourth fixed roll 44d, and the take-up roll 42 each have a roller shaft (not shown) with a rotation axis. Each roller shaft is a linear rod-shaped member and is arranged parallel to each other. The third fixed roll 44c, the second dancer roll 43b, the fourth fixed roll 44d, and the take-up roll 42 each rotate about the rotation axis of the roller shaft. Also, the axial centers of the roller shafts of the third fixed roll 44c, the second dancer roll 43b, the fourth fixed roll 44d, and the take-up roll 42 are arranged substantially parallel to the axial centers of the roller shafts of the pay-out roll 41, the first fixed roll 44a, the first dancer roll 43a, and the second fixed roll 44b, respectively. Therefore, the conveyance direction T is also a direction substantially orthogonal to the direction of the axial centers of the roller shafts of the third fixed roll 44c, the second dancer roll 43b, the fourth fixed roll 44d, and the take-up roll 42, respectively. The carrier sheet 10 is arranged parallel to the plane formed by the direction of the axial center of the roller shaft and the conveyance direction T. Thereby, the carrier sheet 10 can be stably wound by the take-up roll 42. Note that the second dancer roll 43b is arranged between the third fixed roll 44c and the fourth fixed roll 44d in the conveyance direction T, and the tension applied to the carrier sheet 10 is adjusted by adjusting the vertical position of the second dancer roll 43b and the load applied to the second dancer roll 43b. The rotation speeds of the pay-out roll 41 and the take-up roll 42 can be changed. When the rotation speeds of the pay-out roll 41 and the take-up roll 42 are changed, the conveyance speed of the carrier sheet 10 changes. The pay-out roll 41 and the take-up roll 42 function as a conveyance control unit for changing the conveyance speed of the carrier sheet 10.

[0028] The manufacturing apparatus 40 for a ceramic green sheet can include a thickness measuring device 1 and a coating film forming unit 30. Therefore, based on the data of the thickness of the coating film 20 measured by the thickness measuring device 1, that is, the coating film of the ceramic slurry or the ceramic green sheet 21 formed by drying the coating film of the ceramic slurry, in the coating film forming unit 30, while controlling the supply amount of the ceramic slurry, the ceramic slurry can be applied onto the carrier sheet 10 to form the ceramic green sheet 21.

[0029] In this way, in the manufacturing apparatus 40 for a ceramic green sheet, the data of the thickness of the applied ceramic slurry or the ceramic green sheet 21 formed by drying the coating film of the ceramic slurry can be fed back to the coating film forming unit 30, and the supply amount of the ceramic slurry can be configured to be quickly controlled. Therefore, it becomes possible to continuously and reliably manufacture the ceramic green sheet 21 with a uniform thickness.

[0030] The first measuring unit 1A of the thickness measuring device 1 measures the thickness of the carrier sheet 10 before applying the ceramic slurry. The second measuring unit 1B of the thickness measuring device 1 measures the combined thickness of the coating film 20 and the ceramic green sheet 21, that is, the ceramic green sheet 21 formed by drying the coating film of the ceramic slurry and the carrier sheet 10. As described above, the first measuring unit 1A is arranged upstream in the conveying direction T of the coating film forming unit 30, and the second measuring unit 1B is arranged downstream in the conveying direction T of the coating film forming unit 30. Note that, among the conveying direction T, the direction from the second fixed roll 44b to the third fixed roll 44c is parallel to the horizontal direction, and the carrier sheet 10 is arranged parallel to the horizontal plane. The first measuring unit 1A, the coating film forming unit 30, and the second measuring unit 1B are arranged linearly side by side in a side view. However, the arrangement of the first measuring unit 1A, the coating film forming unit 30, and the second measuring unit 1B does not have to be arranged linearly side by side. It is sufficient that the first measuring unit 1A, the coating film forming unit 30, and the second measuring unit 1B are arranged in order from the conveying source to the conveying destination in the conveying direction T.

[0031] The first measurement unit 1A disposed upstream (rear side) in the transport direction T of the carrier sheet 10 includes an irradiation head that irradiates light and a light receiving head that receives transmitted light or reflected light. The second measurement unit 1B disposed downstream (front side) in the transport direction T of the carrier sheet 10 includes an irradiation head that irradiates radiation emitted when an electron beam emitted from a cathode collides with an anode, and a measurement head that detects the transmission amount (absorption amount) of the radiation.

[0032] In the first measurement unit 1A, when receiving transmitted light, the light irradiation head and the light receiving head are installed at positions facing each other with the carrier sheet 10 interposed therebetween. In the spectroscopic interference method for receiving reflected light, the light irradiation head and the light receiving head are arranged on the same side of the carrier sheet 10. Also, in the second measurement unit 1B, the radiation irradiation head and the measurement head are installed at positions facing each other with the ceramic green sheet 21 backed by the carrier sheet 10 interposed therebetween in order to measure the transmission amount (absorption amount) of the radiation.

[0033] (Carrier Sheet) The ceramic green sheet 21 is formed by drying a ceramic slurry applied to the surface of a sheet-like or film-like carrier sheet 10 selected from materials such as PP, PET, or PEN. The material of the carrier sheet is not particularly limited, and it is preferably widely a resin sheet. Also, the carrier sheet preferably has translucency. In order to efficiently manufacture a multilayer ceramic capacitor, a laminated sheet in which a plurality of sheets having different physical properties are stacked can be used. Also, in order to efficiently peel the ceramic green sheet formed on the carrier sheet 10 from the carrier sheet 10, a sheet called a release layer can be provided on the surface of the carrier sheet 10 to which the ceramic slurry is applied. Note that the width dimension of the carrier sheet 10 is about 100 to 1000 mm, and the thickness dimension is about 0.01 mm to 1.0 mm. The carrier sheet is sometimes also called a carrier film.

[0034] The carrier sheet 10 is prepared, for example, in a state of being wound around an unwinding roll 41 with a PET sheet or a PET film. Then, in the manufacturing apparatus 40 for the ceramic green sheet, while the carrier sheet 10 is being conveyed from the unwinding roll 41 to the winding roll 42, a ceramic slurry is applied by the coating film forming section 30 and wound up by the winding roll 42 together with the formed ceramic green sheet 21.

[0035] (First measurement section) The first measurement section 1A is arranged upstream of the coating film forming section 30 in the conveyance direction T of the carrier sheet 10.

[0036] The first measurement section 1A is preferably a non-contact type using, for example, the spectral interference method. In the spectral interference method, the first measurement section 1A irradiates light onto the carrier sheet 10 before the coating film 20 is formed and receives the light reflected by the carrier sheet 10. Therefore, the first measurement section 1A includes an irradiation head for irradiating light and a light receiving head for receiving the reflected light, and the light irradiation head and the light receiving head are arranged on the same side of the surface of the carrier sheet 10.

[0037] The spectroscopic interference method referred to here is a method for obtaining the film thickness based on the following principle. That is, when the carrier sheet 10 before the ceramic slurry is applied is irradiated with light, a first reflected light from the interface between the surface of the carrier sheet 10 and the atmosphere with a different refractive index, and light incident from the surface of the carrier sheet 10 pass through the inside of the carrier sheet 10 and reach the interface between the back surface of the carrier sheet 10 and the atmosphere with a different refractive index to generate a second reflected light. These two reflected lights are generated by a plurality of lights from the same light source with different optical path lengths and cause interference. Due to the interference of light, if the phases are the same, they strengthen each other, and if the phases are opposite, they weaken each other. By spectroscopically analyzing this interference light and performing Fourier transform on the obtained spectroscopic waveform pattern, etc., the optical distance can be obtained. When obtaining the film thickness of the carrier sheet 10 itself, the value of the thickness of the carrier sheet 10 can be obtained by performing calculations using the refractive index corresponding to the material composition of the carrier sheet 10.

[0038] When obtaining the thickness information of the carrier sheet 10 by the spectroscopic interference method, as the irradiation light, visible light, laser light, superluminescent diode (SLD) light, etc. can be used. In particular, it is preferable to use coherent light with a wavelength of 400 to 900 nm generated from an SLD (Super Luminescent Diode) light source.

[0039] The first measurement unit 1A converts the received light into an electrical signal. Since the received light changes depending on the thickness of the carrier sheet 10, the electrical signal obtained by converting the received light contains information related to the thickness. Here, the information related to the thickness is referred to as thickness information. The first measurement unit 1A acquires the measurement position of the carrier sheet 10 and the thickness information at the measurement position.

[0040] Since the first measurement unit 1A obtains the thickness information of the carrier sheet 10 before the coating film is formed by an optical interference measurement method, the measurement error can be relatively small. The thickness information of the carrier sheet 10 can be accurately grasped.

[0041] The first measurement unit 1A is arranged at a predetermined distance in a direction perpendicular to the surface of the carrier sheet 10, and irradiates light from a plurality of light sources arranged at regular intervals along the width direction of the carrier sheet 10 orthogonal to the conveyance direction T. The width direction of the carrier sheet 10 orthogonal to the conveyance direction T is parallel to the axial direction of the roller. For example, it is a light source amplified by induced emission, and more specifically, a laser light source.

[0042] FIG. 1 shows an example of the thickness measurement device 1, and shows the form of the thickness measurement device 1 when viewed from above the carrier sheet 10 on which the ceramic slurry is applied by the coating film forming unit 30.

[0043] The first measurement unit 1A is arranged upstream of the coating film forming unit 30 in the conveyance direction T in which the carrier sheet 10 is conveyed. A plurality of first measurement units 1A are arranged in the width direction of the carrier sheet 10. As the carrier sheet 10 moves in the conveyance direction T, the first measurement unit 1A can measure the thickness of the entire surface of the carrier sheet 10.

[0044] The first measurement unit 1A includes a plurality of light sources arranged side by side at a predetermined interval along the width direction of the carrier sheet 10 orthogonal to the conveyance direction T. The interval between the light sources can be 10 to 250 mm. Note that the position of the light sources and the interval between the light sources in the first measurement unit 1A are not limited to FIG. 1. FIG. 1 shows an embodiment in which nine light sources are arranged, but the number of light sources is not limited thereto. In FIG. 1, the plurality of light sources are arranged side by side parallel to the width direction of the carrier sheet 10 orthogonal to the conveyance direction T, but may be arranged side by side in a direction intersecting the width direction of the carrier sheet 10.

[0045] In the spectroscopic interference method, since the irradiation head for irradiating light and the light-receiving head for receiving the reflected light are arranged on the same side of the carrier sheet 10, the light-receiving head can be arranged on the optical path where the light irradiated from the light source shown in FIG. 1 becomes the reflected light and is reflected from the carrier sheet 10. Therefore, when arranging a plurality of light sources, a plurality of light-receiving heads can be arranged corresponding to each light source.

[0046] The first measurement unit 1A intermittently measures the thickness of the carrier sheet 10 moving in the transport direction T at predetermined intervals. In FIG. 1, each measurement point is indicated by a dot, but as the carrier sheet 10 moves in the transport direction T, the measurement points on the carrier sheet 10 are shown by a dotted line. By adjusting the predetermined interval, the number of measurement points can be increased or decreased.

[0047] As shown in FIG. 2, the first control unit 11A is located upstream of the coating film forming unit 30 in the transport direction T in which the carrier sheet 10 is transported, and is arranged below the first measurement unit 1A via the carrier sheet 10.

[0048] The first control unit 11A controls the intensity of the light irradiated from the light source 9 of the first measurement unit 1A and the irradiation interval. Further, a support roll for supporting the carrier sheet 10 moving in the transport direction T and maintaining the carrier sheet 10 horizontally may be arranged in the first control unit 11A.

[0049] The first control unit 11A that controls the intensity of the light irradiated from the light source of the first measurement unit 1A and the irradiation interval is not limited to being arranged below the carrier sheet 10, and may be arranged above the carrier sheet 10. Further, it is not limited to being arranged upstream of the coating film forming unit 30, and may also be arranged downstream of the coating film forming unit 30.

[0050] The thickness information measured by the first measurement unit 1A is used by averaging the data of a plurality of consecutive measurement points, as will be described later. FIG. 1 shows an embodiment in which there are 15 measurement points to be averaged, and the 15 measurement points are schematically enlarged and shown. Among the plurality of measurement points used for calculating the average value, the measurement point located at the center is recorded as, for example, the A point. The position of the A point is taken as the first position. Note that the number of measurement points to be averaged can be appropriately set according to the measurement conditions.

[0051] As shown in FIG. 1, the thickness information measured by the first measurement unit 1A is used by averaging the data of a plurality of consecutive measurement points. FIG. 1 shows an embodiment in which there are 15 measurement points to be averaged, and the 15 measurement points are schematically enlarged and shown. Usually, the number of measurement points to be averaged is from 1 to 100, but it can be appropriately set according to the measurement conditions.

[0052] Among the plurality of measurement points used for calculating the average value, the measurement point located at the center is recorded as, for example, the A point (the first position). Note that since the plurality of measurement points used for calculating the average value move sequentially, for the average value of the next measurement point, some of the measurement values used to derive the average value last time are also used.

[0053] The information on the measurement position and thickness thus obtained is sent from the first measurement unit 1A to the arithmetic processing unit. Note that the size of the measurement point is usually 10 to 20 mm in diameter, but is not limited thereto.

[0054] The first measurement unit 1A irradiates light from a plurality of light sources arranged along the width direction of the carrier sheet 10 orthogonal to the conveyance direction T to obtain the thickness information of the carrier sheet 10. By using a spectroscopic interferometer, defects in the carrier sheet 10 can also be detected.

[0055] (Second measurement unit) The second measurement unit 1B is arranged downstream of the coating film forming unit 30 in the transport direction T of the carrier sheet 10. The second measurement unit 1B irradiates radiation onto the coating film 20 and the carrier sheet 10, that is, the ceramic green sheet 21 formed by drying the coating film of the ceramic slurry or the coating film of the ceramic slurry, and the carrier sheet 10, and detects the radiation transmitted through the coating film 20 and the carrier sheet 10. The second measurement unit 1B converts the detected radiation into an electrical signal. Since the detected amount of radiation changes depending on the thicknesses of the coating film 20 and the carrier sheet 10, the electrical signal obtained by converting the detected radiation contains information related to the thickness. Therefore, the second measurement unit 1B acquires the measurement position of the coating film 20 and the carrier sheet 10 and the thickness information at the measurement position. As shown in FIG. 1, the thickness information measured by the second measurement unit 1B is used by averaging the data of a plurality of measurement points that are continuously diagonal. FIG. 1 shows an aspect in which seven measurement points are averaged, and the seven measurement points are schematically enlarged and shown. Normally, the number of measurement points to be averaged is from 1 to 100, but it may be appropriately set according to the measurement conditions. Among the plurality of measurement points used for calculating the average value, the measurement point located at the center is recorded as, for example, the B point. The position of the B point is set as the second position. Note that since the plurality of measurement points used for calculating the average value move sequentially, a part of the measurement values used for deriving the average value last time is also used for the average value of the next measurement point. The distance between the B point (the second position) and a specific A point (the first position) among the plurality of A points (the first positions) acquired by the first measurement unit 1A is selected to be within a predetermined range. The selection of the B point is realized by changing the conveyance speed of the carrier sheet 10. The conveyance speed of the carrier sheet 10 is realized by controlling the rotational speeds of the pay-out roll 41 and the take-up roll 42 as the conveyance control unit. The speeds of the pay-out roll 41 and the take-up roll 42 are controlled so that the positional deviation from the specific A point decreases. As a result, the B point is selected in a state where the positional deviation from the specific A point has decreased. The B point is selected to be within a predetermined range with respect to the specific A point and thus corresponds to the specific A point. Note that the predetermined range is within 200 μm, and more preferably within 15 μm.

[0056] The second measurement unit 1B intermittently measures at predetermined intervals while reciprocating along the width direction of the carrier sheet 10 orthogonal to the conveyance direction T. Since the carrier sheet 10 moves in the conveyance direction T, the second measurement unit 1B measures the carrier sheet 10 in a zigzag pattern as shown by the dotted line in FIG. 1. As described above, the measurement position by the second measurement unit 1B is controlled by the rotational speeds of the pay-out roll 41 and the take-up roll 42 as the conveyance control unit.

[0057] The second measurement unit 1B has a component in the direction orthogonal to the conveyance direction T of the carrier sheet 10 and is provided so as to be reciprocally movable relative to the carrier sheet 10 on a plane parallel to the surface of the carrier sheet 10.

[0058] The reciprocating movement of the second measurement unit 1B in the width direction of the carrier sheet 10 orthogonal to the conveyance direction T can be executed by various linear motion mechanisms using a motor, a cylinder, a linear motor, etc. as a drive source and using a ball screw, a rack and pinion, a timing belt, a guide, etc.

[0059] The unwinding roll 41, the first fixed roll 44a, the first dancer roll 43a, the second fixed roll 44b, the third fixed roll 44c, the second dancer roll 43b, the fourth fixed roll 44d, and the winding roll 42 for transporting the carrier sheet 10 all have axes arranged parallel to the width direction of the carrier sheet 10 perpendicular to the transport direction T of the carrier sheet 10. The reciprocating movement of the second measuring unit 1B in the width direction of the carrier sheet 10 perpendicular to the transport direction T will reciprocate parallel to the axes of the above-mentioned respective rolls.

[0060] The second measuring unit 1B irradiates radiation and can measure the thicknesses of the carrier sheet 10 and the ceramic green sheet 21 from the transmittance of the radiation or the absorption coefficient of the irradiation target. As the radiation, X-rays or β-rays can be used, but it is also possible to measure by combining these radiations and utilizing the absorption coefficient difference.

[0061] It can be selected according to specific conditions such as the raw materials constituting the carrier sheet 10 and the ceramic green sheet 21 and the thickness of the irradiation target of the radiation. Here, it is preferable to use X-rays, which are electromagnetic waves with a wavelength of 1 pm or more and 10 nm or less, as the radiation irradiated by the second measuring unit 1B.

[0062] As shown in FIG. 2, the second control unit 11B is downstream of the coating film forming unit 30 in the transport direction T in which the carrier sheet 10 is transported and is disposed below the second measuring unit 1B through the carrier sheet 10.

[0063] The second control unit 11B controls the operation of the second measuring unit 1B that reciprocates in the width direction of the carrier sheet 10 perpendicular to the transport direction T as shown in FIG. 1 and the interval of the radiation intermittently irradiated by the second measuring unit 1B. Further, a measuring head for detecting the transmission amount (absorption amount) of the radiation can be arranged in the second control unit 11B, and control can be performed to send the electrical signal converted from the detected radiation to the arithmetic processing unit.

[0064] The second control unit 11B may be provided with support rolls for supporting and horizontally maintaining the carrier sheet 10 that advances in the conveyance direction T.

[0065] The second control unit 11B for controlling the operation of the second measurement unit 1B that reciprocates in the width direction of the carrier sheet 10 and the interval of the radiation intermittently irradiated by the second measurement unit 1B is not limited to being disposed below the carrier sheet 10, and may be disposed above the measurement unit of the second measurement unit 1B and the carrier sheet 10. Further, it is not limited to being disposed downstream of the coating film forming unit 30, and may also be disposed upstream of the coating film forming unit 30.

[0066] The information on the measurement position and thickness measured by the second measurement unit 1B is sent to the arithmetic processing unit.

[0067] (Arithmetic processing unit) The arithmetic processing unit calculates the thickness of the coating film 20 at a predetermined position of the carrier sheet 10 using the thickness information corresponding to the position information measured by the first measurement unit 1A and the thickness information corresponding to the position information measured by the second measurement unit 1B. A specific calculation method is shown below.

[0068] In the arithmetic processing unit, based on the thickness information of a specific A point (first position) sent from the first measurement unit 1A and the thickness information of a B point (second position) corresponding to the specific A point sent from the second measurement unit 1B, the thickness of the coating film 20, that is, the coating film of the ceramic slurry or the ceramic green sheet 21 formed by drying the coating film of the ceramic slurry is calculated. As described above, the position deviation in the conveyance direction between the first position and the second position is controlled to decrease by the pay-out roll 41 and the take-up roll 42 as the conveyance control unit. The distance between the A point and the B point is within a predetermined range, and the thickness information of the A point and the thickness information of the B point can be treated as the thickness at the same position. The first position is the thickness information of the carrier sheet 10, and the second position is the thickness information of the carrier sheet 10 and the ceramic green sheet 21. Therefore, by subtracting the thickness information of the first position from the thickness information of the second position, the thickness of the ceramic green sheet 21 can be calculated. Note that the position deviation between the first measurement position and the second measurement position may not be reduced by the unwinding roll 41 and the winding roll 42 as the conveyance control unit. The arithmetic processing unit has the position information of all A points sent from the first measurement unit 1A and the position information of B points sent from the second measurement unit 1B. The arithmetic processing unit can select the B point with the position information having the smallest deviation with respect to the position information of a specific A point. It is also possible to calculate the thickness of the ceramic green sheet 21 by subtracting the thickness information of the specific A point from the thickness information of the B point with the position information having the smallest deviation with respect to the position information of the specific A point.

[0069] The arithmetic processing unit constituting the thickness measuring device 1 calculates the thickness of the coating film 20, that is, the coating film of the ceramic slurry or the ceramic green sheet 21 formed by drying the coating film of the ceramic slurry, from the thickness information from the first measurement unit 1A and the second measurement unit 1B. Then, the calculated thickness data of the ceramic green sheet 21 is sent to the supply amount control unit, and the supply amount of the ceramic slurry can be controlled to adjust the coating amount of the ceramic slurry on the carrier sheet 10 in the coating film forming unit 30. Also, by incorporating the arithmetic processing unit and the supply amount control unit of the thickness measuring device 1 into the coating film forming unit 30, the coating amount of the ceramic slurry may be controlled using the calculated thickness data of the ceramic green sheet 21.

[0070] (Manufacture of Ceramic Green Sheet) The ceramic slurry for producing the ceramic green sheet 21 can be obtained by preparing ceramic particles containing Ba, Ca, Ti, etc., a binder, an organic solvent, etc., and wet-mixing them. Known binders and solvents can be used for the ceramic slurry.

[0071] The ceramic slurry is transferred from the storage tank to the coating film forming section 30 by a pump. The coating film forming section 30 includes a coating section for coating the ceramic slurry. Further, it can include a drying section for drying the coated ceramic slurry.

[0072] The coating film forming section 30 applies the ceramic slurry onto the carrier sheet 10 by methods such as a die coater or a gravure coater. In particular, when the carrier sheet 10 is composed of multiple layers with a release layer disposed as the top layer, it is applied onto the release layer, dried, and the ceramic green sheet 21 is formed.

[0073] The thickness of the applied ceramic slurry is 0.1 to 50 μm. Also, the drying of the applied ceramic slurry is performed by evaporating the solvent contained in the ceramic slurry using far-infrared rays, a heating heater, etc., to form a ceramic green sheet. The drying temperature is 30 to 100 °C.

[0074] The manufacturing apparatus 40 for the ceramic green sheet includes a thickness measuring device 1 and a coating film forming section 30 that forms the ceramic green sheet 21 by applying the ceramic slurry onto the carrier sheet 10 while controlling the supply amount of the ceramic slurry based on the data of the thickness of the coating film 20 measured by the thickness measuring device 1, that is, the coating film of the ceramic slurry or the ceramic green sheet formed by drying the coating film of the ceramic slurry. As the supply amount control section for realizing the film thickness feedback control, for example, an electromagnetic valve can be arranged, and a flow meter such as an electromagnetic type or an ultrasonic type can be arranged.

[0075] The manufacturing apparatus 40 for a ceramic green sheet is configured such that data on the thickness of the applied ceramic slurry or the accurate sheet thickness measured after the forming of the ceramic green sheet 21 is fed back to the coating film forming section 30, and the supply amount of the ceramic slurry is promptly controlled. Therefore, it becomes possible to continuously and reliably manufacture a ceramic green sheet 21 with uniform thickness.

[0076] (Manufacture of Multilayer Ceramic Capacitor) Next, an example of a method for manufacturing a multilayer ceramic capacitor will be described.

[0077] FIG. 3 is an external perspective view of a multilayer ceramic capacitor. Further, FIG. 4 is a cross-sectional view taken along line IV-IV of the multilayer ceramic capacitor shown in FIG. 3.

[0078] First, a ceramic green sheet 21 manufactured by the manufacturing apparatus 40 for a ceramic green sheet and a conductive paste for an internal electrode are prepared. The conductive paste for an internal electrode contains a binder and a solvent, and known organic binders and organic solvents can be used. The conductive paste for an internal electrode forms the internal electrode 53.

[0079] Next, on the ceramic green sheet, for example, the conductive paste for an internal electrode is printed in a predetermined pattern by screen printing, gravure printing, or the like, thereby forming an internal electrode pattern.

[0080] Next, a predetermined number of outer-layer ceramic green sheets on which no internal electrode pattern is formed are laminated, and the ceramic green sheet on which the internal electrode is formed is sequentially laminated thereon, and then a predetermined number of outer-layer ceramic green sheets are laminated thereon to produce a laminated sheet. The ceramic green sheet forms the dielectric layer 52 that constitutes the multilayer ceramic capacitor 50.

[0081] The obtained laminated sheet is pressed in the lamination direction by means such as hydrostatic pressing to produce a laminated block. Next, the laminated block is cut into a predetermined size to cut out laminated chips. At this time, the corners and ridges of the laminated chips may be rounded by barrel polishing or the like.

[0082] Furthermore, the laminated body 51 is produced by firing the laminated chips. The firing temperature at this time preferably ranges from 900°C to 1300°C, although it depends on the materials of the dielectric and the internal electrodes.

[0083] Conductive paste for external electrodes is applied to both end faces of the obtained laminated body 51 and baked to form a baked layer 54a of the external electrode 54. The baking temperature at this time preferably ranges from 700°C to 900°C. Thereafter, if necessary, a plating layer 54b is applied to the surface of the baked layer. The laminated ceramic capacitor is manufactured through the above steps.

[0084] In the embodiment of the present invention, a form is shown in which the functional sheet is a coating film of ceramic slurry or a ceramic green sheet 21 formed by drying the coating film of ceramic slurry. However, the functional sheet is not limited to such ceramic slurry or ceramic green sheet. The functional sheet may be a sheet of material that can be disposed on the carrier sheet 10. Depending on the material of the functional sheet disposed on the carrier sheet 10, either X-ray or β-ray radiation is used. When X-ray is used, an optimal wavelength is selected according to the properties of the material disposed on the carrier sheet 10. When β-ray is used, an optimal radiation source, for example, 85 Kr, 147 Pm, 204 Ti, 90 Sr, etc. are used. Also, although coating is shown as an example of the arrangement, it is not limited to coating. The functional sheet may be disposed on the carrier sheet 10 by adhesion, vapor deposition, spraying, or the like.

[0085] As described above, the embodiments of the present invention have been explained. However, the present invention is not limited to the embodiments, and can be implemented in various aspects without departing from the gist of the present invention. The present invention includes the following combinations.

[0086] <1> A thickness measuring device for measuring the thickness of a coating film formed on a carrier sheet to be conveyed, A first measuring unit that acquires thickness information of the carrier sheet before the coating film is formed by irradiating light, and acquires a first position that is the position where the thickness information of the carrier sheet is acquired, A second measuring unit that acquires thickness information of the carrier sheet and the coating film after the coating film is formed by irradiating radiation, and acquires a second position that is the position where the thickness information of the carrier sheet and the coating film is acquired, An arithmetic processing unit that calculates the thickness of the coating film based on the thickness information of the carrier sheet at the first position and the thickness information at the second position within a predetermined range with respect to the first position, A thickness measuring device including: <2> A thickness measuring device including a conveyance unit that conveys a carrier sheet in a conveyance direction, a composite sheet forming unit that forms a composite sheet in which a functional sheet is disposed on the carrier sheet, and a thickness measuring unit that measures the thickness of a measurement target to be conveyed, The thickness measuring unit includes: A first measuring unit that acquires thickness information of the carrier sheet before the functional sheet is disposed by irradiating light, A second measuring unit that acquires thickness information of the composite sheet after the functional sheet is disposed by irradiating radiation, A conveyance control unit that controls the conveyance unit so as to reduce a positional deviation in the conveyance direction between a first position of the carrier sheet irradiated with the light by the first measuring unit and a second position of the carrier sheet irradiated with the radiation by the second measuring unit, An arithmetic processing unit that calculates the thickness of the functional sheet based on the thickness information of the carrier sheet at the first position and the thickness information of the composite sheet at the second position; A thickness measuring device including the same. <3> The first measuring unit is arranged with a predetermined distance provided in a direction perpendicular to the surface of the carrier sheet being conveyed, and the second measuring unit has a component in a direction orthogonal to the conveying direction of the carrier sheet and is provided so as to be reciprocally movable relative to the carrier sheet on a plane parallel to the surface of the carrier sheet. The thickness measuring device according to <1> or <2>. <4> The first measuring unit performs interference measurement. The thickness measuring device according to any one of <1> to <3>. <5> The first measuring unit performs reflection type interference measurement. The thickness measuring device according to any one of <1> to <4>. <6> The first measuring unit irradiates light from a plurality of light sources arranged at regular intervals along the width direction of the carrier sheet orthogonal to the conveying direction. The thickness measuring device according to any one of <1> to <5>. <7> The second measuring unit irradiates X-rays or β-rays as radiation. The thickness measuring device according to any one of <1> to <6>. <8> The thickness measuring device according to <1>, A coating film forming unit that controls the coating amount based on the thickness of the coating film measured by the thickness measuring device, and includes: The coating film is a coating film of a ceramic slurry or a ceramic green sheet formed by drying the coating film of the ceramic slurry. A manufacturing device for a ceramic green sheet that forms a ceramic green sheet by applying a ceramic slurry on a carrier sheet. <9> A method for manufacturing a ceramic green sheet using the thickness measuring device according to <1>, The coating film is a coating film of a ceramic slurry or a ceramic green sheet formed by drying the coating film of the ceramic slurry. A method for manufacturing a ceramic green sheet, in which a ceramic slurry is applied onto a carrier sheet while controlling the coating amount by a coating film forming unit based on the thickness of the coating film of the ceramic slurry or the ceramic green sheet calculated by the thickness measuring device to form a ceramic green sheet.

Explanation of Signs

[0087] 1 Thickness measuring device (thickness measuring unit) 1A First measuring unit 1B Second measuring unit 10 Carrier sheet 11 Control unit 11A First control unit 11B Second control unit 20 Coating film 21 Ceramic green sheet (functional sheet) 30 Coating film forming unit (composite sheet forming unit) 40 Manufacturing device for ceramic green sheet (manufacturing device for composite sheet) 41 Unwinding roll (conveyance control unit) 42 Winding roll (conveyance control unit) 43a First dancer roll 43b Second dancer roll 44a First fixed roll 44b Second fixed roll 44c Third fixed roll 44d Fourth fixed roll 50 Multilayer ceramic capacitor 51 Laminate 52 Dielectric layer 53 Internal electrode 54 External electrode 54a Baked layer 54b Plated layer A A point (first position) B B point (second position) T Conveyance direction

Claims

1. A thickness measuring device for measuring the thickness of a coating film formed on a carrier sheet to be conveyed, comprising: a first measuring unit configured to obtain thickness information of the carrier sheet before the coating film is formed by irradiating light, and to obtain a first position which is the position where the thickness information of the carrier sheet is obtained; a second measuring unit configured to obtain thickness information of the carrier sheet and the coating film after the coating film is formed by irradiating radiation, and to obtain a second position which is the position where the thickness information of the carrier sheet and the coating film is obtained; an arithmetic processing unit configured to calculate the thickness of the coating film based on the thickness information of the carrier sheet at the first position and the thickness information at the second position within a predetermined range with respect to the first position; A thickness measuring device including the above.

2. A thickness measuring device including a conveying unit configured to convey a carrier sheet in a conveying direction, a composite sheet forming unit configured to form a composite sheet in which a functional sheet is disposed on the carrier sheet, and a thickness measuring unit configured to measure the thickness of a measurement target to be conveyed, wherein: the thickness measuring unit includes a first measuring unit configured to obtain thickness information of the carrier sheet before the functional sheet is disposed by irradiating light; a second measuring unit configured to obtain thickness information of the composite sheet after the functional sheet is disposed by irradiating radiation; a conveyance control unit configured to control the conveyance unit so as to reduce a positional deviation in the conveyance direction between a first position of the carrier sheet irradiated with the light by the first measuring unit and a second position of the carrier sheet irradiated with the radiation by the second measuring unit; an arithmetic processing unit configured to calculate the thickness of the functional sheet based on the thickness information of the carrier sheet at the first position and the thickness information of the composite sheet at the second position; A thickness measuring device including the above.

3. The thickness measuring device according to claim 1 or 2, wherein the first measuring unit is disposed with a predetermined distance provided in a direction perpendicular to the surface of the carrier sheet to be conveyed, the second measuring unit has a component in a direction orthogonal to the conveying direction of the carrier sheet, and is provided so as to be relatively reciprocally movable with respect to the carrier sheet on a plane parallel to the surface of the carrier sheet.

4. The thickness measuring device according to claim 1 or 2, wherein the first measuring unit performs interference measurement.

5. The first measurement unit is the thickness measurement device according to claim 4 that performs reflection-type interference measurement.

6. The first measurement unit is the thickness measurement device according to claim 3 that irradiates light from a plurality of light sources arranged at regular intervals along the width direction of the carrier sheet orthogonal to the conveyance direction.

7. The second measurement unit is the thickness measurement device according to claim 1 or 2 that irradiates X-rays or β-rays as radiation.

8. The thickness measurement device according to claim 1, and a coating film forming unit that controls the coating amount based on the thickness of the coating film measured by the thickness measurement device, wherein the coating film is a coating film of ceramic slurry or a ceramic green sheet formed by drying the coating film of ceramic slurry, and a manufacturing device for a ceramic green sheet that forms a ceramic green sheet by applying a ceramic slurry onto the carrier sheet.

9. A method for manufacturing a ceramic green sheet using the thickness measurement device according to claim 1, wherein the coating film is a coating film of ceramic slurry or a ceramic green sheet formed by drying the coating film of ceramic slurry, and a method for manufacturing a ceramic green sheet that forms a ceramic green sheet by applying a ceramic slurry onto the carrier sheet while the coating film forming unit controls the coating amount based on the thickness of the coating film of ceramic slurry or the ceramic green sheet calculated by the thickness measurement device.

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