Thickness measurement device

Abstract

A thickness measurement device (1) comprises: a plate (4) in which a long hole (43) extending in a first direction is formed; a first guide part (5) that is provided on a first surface (41) of the plate (4) on one side of the long hole (43), and extends along the first direction; a first measurement part (7) that is supported by the first guide part (5) and can move along the first direction; a second guide part (6) that is provided on the first surface (41) on another side of the long hole (43) and extends along the first direction; and a second measurement part (8) that is supported by the second guide part (6) and can move along the first direction. The thickness of a measurement target, which passes through the long hole (43) and a gap between the first measurement part (7) and the second measurement part (8), is measured.

Description

Thickness Measuring Device

[0001] The present invention relates to a thickness measurement device.

[0002] A thickness measurement device is known that includes two opposing measurement units and measures the thickness of an object passing between the measurement units. As disclosed in Patent Document 1, the thickness measurement device includes a beam that supports one measurement unit from above and a beam that supports the other measurement unit from below. The two measurement units move synchronously along the beams. By passing the object between the two measurement units while the two measurement units move synchronously, thickness measurements can be performed over a wide range of the object.

[0003] An example of a method for measuring thickness is to detect radiation emitted from one measuring unit with the other measuring unit, calculate the amount of attenuation of the radiation as it penetrates the object being measured, and measure the thickness based on that amount of attenuation.

[0004] In such a thickness measuring device, two beams, one above the other, are supported by stands connected to both ends of the beams, and the stands are fixed to the floor.

[0005] JP 2008-128756 A

[0006] In order to measure the thickness of an object with high accuracy, it is necessary to control the position of the measurement unit with high accuracy. In a configuration in which the measurement unit is supported by beams provided above and below and the beams are connected by a stand, as disclosed in Patent Document 1, high rigidity, shape accuracy, and assembly accuracy are required for the beams and stand, which leads to an increase in the size and cost of the device.

[0007] An object of the present invention is to provide a thickness measuring device that is simple in configuration and capable of highly accurate thickness measurement.

[0008] The thickness measuring device of the present invention comprises a plate having a long hole extending in a first direction formed in a first surface, a first guide portion provided on the first surface on one side of the long hole and extending along the first direction, a first measuring portion supported by the first guide portion and movable along the first direction, a second guide portion provided on the first surface on the other side of the long hole and extending along the first direction, and a second measuring portion supported by the second guide portion and movable along the first direction, and measures the thickness of an object to be measured that passes through the long hole and the gap between the first measuring portion and the second measuring portion.

[0009] According to the present invention, it is possible to obtain a thickness measuring device that is simple in configuration and capable of highly accurate thickness measurement.

[0010] 1 is a perspective view showing a schematic configuration of a thickness measurement device according to embodiment 1. FIG. 2 is a front view of a plate in embodiment 1. FIG. 3 is a cross-sectional view taken along line III-III shown in FIG. 2. FIG. 4 is a partially enlarged perspective view showing an enlarged view of part A shown in FIG. 1. FIG. 5 is a diagram showing an installation example of the thickness measurement device according to embodiment 1.

[0011] A thickness measuring device according to an embodiment of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the embodiment described below.

[0012] 1 is a perspective view showing the schematic configuration of a thickness measurement device according to embodiment 1. The thickness measurement device 1 is a device for measuring the thickness of a film or sheet-like object to be measured, such as an electrode sheet or separator sheet for a secondary battery, paper, a plastic sheet for packaging, a building material sheet, a functional material sheet, an optical film, or a metal foil. The thickness measurement device 1 includes a measurement unit 2 and a control box 3.

[0013] The measurement unit 2 includes a plate 4, a first guide section 5, a second guide section 6, a first measurement section 7, a second measurement section 8, a first scanning unit 9, a second scanning unit 10, a driving device 11, and a frame 12.

[0014] FIG. 2 is a front view of the plate in the first embodiment. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 . The plate 4 is a plate-like member having a rectangular first surface 41. The plate 4 is formed of, for example, resin or metal. A slot 43 extending along a first direction is formed in the first surface 41 of the plate 4. Although not limited thereto, in the first embodiment, the first direction coincides with the longitudinal direction of the first surface 41. Furthermore, in the first embodiment, the direction perpendicular to the first direction, i.e., the lateral direction of the first surface 41, is defined as the second direction. As shown in FIG. 2 , the slot 43 formed in the first surface 41 penetrates to the second surface 42, which is the back surface. The slot 43 is a hole formed in the plate 4 to allow an object to be measured to pass through.

[0015] A plurality of holes 44 are formed in the first surface 41 of the plate 4. The plurality of holes 44 are formed in a row along the first direction on both sides of the elongated hole 43. Pins 45 are inserted into the plurality of holes 44. The pins 45 may be prevented from falling out by being press-fitted into the holes 44, or may be prevented from falling out by using an adhesive or the like. The holes 44 can be formed at specified positions with high precision by, for example, numerically controlled (NC) processing. The holes 44 and the pins 45 function as positioning portions for positioning a first guide portion 5 and a second guide portion 6, which will be described later.

[0016] 1 , the first guide portion 5 is fixed to the first surface 41 of the plate 4. The first guide portion 5 is provided on one side of the elongated hole 43 along the second direction. The first guide portion 5 is a rail member that extends along the first direction.

[0017] The second guide portion 6 is fixed to the first surface 41 of the plate 4. The second guide portion 6 is provided on the other side of the elongated hole 43 along the second direction. The second guide portion 6 is a rail member extending along the first direction. The first guide portion 5 and the second guide portion 6 are arranged to sandwich the elongated hole 43 in the second direction.

[0018] The first guide portion 5 and the second guide portion 6 are fixed in a state in contact with pins 45 provided on the first surface 41. As described above, the holes 44 into which the pins 45 are inserted can be formed at specified positions with high precision by NC machining or the like, so that the first guide portion 5 and the second guide portion 6 can be accurately positioned by fixing them while they are in contact with the pins 45. Since accurate positioning can be achieved simply by abutting them against the pins 45, the work of fixing the first guide portion 5 and the second guide portion 6 is facilitated.

[0019] The first measuring unit 7 is attached to the first guide unit 5 so as to be movable along the direction in which the first guide unit 5 extends, i.e., the first direction. The second measuring unit 8 is attached to the second guide unit 6 so as to be movable along the direction in which the second guide unit 6 extends, i.e., the first direction.

[0020] When the first measurement unit 7 and the second measurement unit 8 are located at the same position along the first direction, a gap is provided between the first measurement unit 7 and the second measurement unit 8. In a front view, the gap provided between the first measurement unit 7 and the second measurement unit 8 overlaps with the elongated hole 43 formed in the plate 4. Therefore, an object to be measured passing inside the elongated hole 43 passes through the gap provided between the first measurement unit 7 and the second measurement unit 8.

[0021] In the thickness measurement device 1, the first measurement unit 7 and the second measurement unit 8 work together to measure the thickness of the object being measured. For example, one of the first measurement unit 7 and the second measurement unit 8 functions as an emission unit that emits radiation or infrared rays. The other of the first measurement unit 7 and the second measurement unit 8 functions as a detection unit that detects the emitted radiation or infrared rays. The radiation or infrared rays pass through the object being measured and reach the detection unit. When passing through the object being measured, radiation is attenuated, and infrared rays are absorbed by the object being measured. The amount of radiation attenuation and the amount of infrared absorption are determined by the thickness and material of the object being measured. The thickness of the object being measured can be calculated by calculating the amount of attenuation and absorption based on the detection results of the detection unit.

[0022] The first scanning unit 9 includes a first driving pulley 91 , a first driven pulley 92 , and a first belt 93 .

[0023] 4 is a partially enlarged perspective view of portion A shown in FIG. 1. The first drive pulley 91 is provided on one side of the elongated hole 43 along the first direction. The first drive pulley 91 is attached to the first surface 41 so as to be rotatable about a rotation axis parallel to the second direction.

[0024] 1 , the first driven pulley 92 is provided on the other side of the elongated hole 43 along the first direction. The first driven pulley 92 is attached to the first surface 41 so as to be rotatable about a rotation axis parallel to the second direction. The first driving pulley 91 and the first driven pulley 92 are arranged on either side of the elongated hole 43 in the first direction.

[0025] The first belt 93 is stretched between the first drive pulley 91 and the first driven pulley 92. As a result, the first belt 93 extends in the first direction on one side of the slot 43 in the second direction. When the first drive pulley 91 rotates, the first belt 93 moves in the first direction, and the first driven pulley 92 also rotates in accordance with the movement of the first belt 93.

[0026] 4, the first measuring unit 7 is fixed to the first belt 93. Since the first measuring unit 7 is fixed to the first belt 93, when the first drive pulley 91 is rotated, the first measuring unit 7 can be moved in the first direction together with the first belt 93.

[0027] The second drive pulley 101 is provided on one side of the elongated hole 43 along the first direction. The second drive pulley 101 is attached to the first surface 41 so as to be rotatable about a rotation axis parallel to the second direction. The rotation axis of the second drive pulley 101 is coaxial with the rotation axis of the first drive pulley 91.

[0028] Returning to FIG. 1 , the second driven pulley 102 is provided on the other side of the elongated hole 43 along the first direction. The second driven pulley 102 is attached to the first surface 41 so as to be rotatable about a rotation axis parallel to the second direction. The second driving pulley 101 and the second driven pulley 102 are arranged on either side of the elongated hole 43 in the first direction. The rotation axis of the second driven pulley 102 is coaxial with the rotation axis of the first driven pulley 92.

[0029] The second belt 103 is stretched between the second drive pulley 101 and the second driven pulley 102. As a result, the second belt 103 extends in the first direction on the other side of the elongated hole 43 (the opposite side of the first belt 93 with respect to the elongated hole 43) in the second direction. The first belt 93 and the second belt 103 are arranged in the second direction so as to sandwich the elongated hole 43 therebetween. When the second drive pulley 101 rotates, the second belt 103 moves in the first direction, and the second driven pulley 102 also rotates in conjunction with the movement of the second belt 103.

[0030] 4, the second measuring unit 8 is fixed to the second belt 103. Since the second measuring unit 8 is fixed to the second belt 103, when the second drive pulley 101 is rotated, the second measuring unit 8 can be moved together with the second belt 103 in the first direction.

[0031] The drive device 11 includes a motor. The drive device 11 is attached to the first surface 41 of the plate 4. As another example, the drive device 11 may be attached to the frame 12. The output shaft 11a of the drive device 11 is coupled to the first drive pulley 91 and the second drive pulley 101. When the drive device 11 is driven, the output shaft 11a rotates, and the first drive pulley 91 and the second drive pulley 101 rotate simultaneously. Therefore, when the drive device 11 is driven, the first measuring unit 7 fixed to the first belt 93 and the second measuring unit 8 fixed to the second belt 103 are moved synchronously in the first direction.

[0032] The frame 12 is a metal frame member fixed to the first surface 41 of the plate 4. However, the frame 12 may be made of other materials such as resin as long as it can maintain an appropriate strength. The frame 12 may also be omitted.

[0033] Returning to FIG. 1 , the control box 3 is box-shaped. The control box 3 is not fixed to the plate 4 and is provided independently from the measurement unit 2. The control box 3 houses components other than mechanical elements for moving the first measurement unit 7 and the second measurement unit 8. For example, the control box 3 houses a power supply and a control unit 30. The control unit 30 includes, for example, a control device (such as a programmable logic controller (PLC)), a control board, and a drive device driver. If the first measurement unit 7 or the second measurement unit 8 has a component that is driven by air, a pneumatic device may be housed inside the control box 3. An example of using air is a configuration in which, if the first measurement unit 7 houses a radiation source and emits radiation, a shutter that covers an opening through which the radiation source is emitted is opened and closed by air. The control unit 30 is an example of a control unit that controls the movement of the first measurement unit 7 and the second measurement unit 8. The control box 3 has an opening 3a formed therein through which power lines, signal lines, communication lines, air supply pipes, etc. that connect the components provided inside with the elements provided on the plate 4 pass.

[0034] The thickness measuring device 1 described above comprises a plate 4 in which a long hole 43 extending in a first direction is formed, a first guide portion 5 provided on a first surface 41 of the plate 4 on one side of the long hole 43 and extending along the first direction, a first measuring portion 7 supported by the first guide portion 5 and movable along the first direction, a second guide portion 6 provided on the first surface 41 on the other side of the long hole 43 and extending along the first direction, and a second measuring portion 8 supported by the second guide portion 6 and movable along the first direction, and measures the thickness of an object to be measured 15 passing through the long hole 43 and the gap between the first measuring portion 7 and the second measuring portion 8.

[0035] In order to measure the thickness of the object to be measured 15 with high accuracy, it is necessary to control the positions of the first measurement unit 7 and the second measurement unit 8 with high accuracy. In order to control the positions of the first measurement unit 7 and the second measurement unit 8 with high accuracy, it is necessary to accurately position the first guide unit 5 and the second guide unit 6 that support them. In this embodiment, the first guide unit 5 and the second guide unit 6 are fixed to the same surface (first surface 41), making it difficult for the first guide unit 5 and the second guide unit 6 to become misaligned. Furthermore, the plate 4 to which the first guide unit 5 and the second guide unit 6 are fixed is a plate-shaped member, which improves rigidity. Therefore, distortion of the plate 4 due to distortion of the installation surface on which the measurement unit 2 is installed is unlikely to occur, and thus misalignment between the first guide unit 5 and the second guide unit 6 is unlikely to occur. Furthermore, because the first guide unit 5 and the second guide unit 6 are fixed to the same surface (first surface 41), differences in distortion between the portions of the plate 4 are unlikely to occur even if temperature differences occur between the portions. Furthermore, because the first guide unit 5 and the second guide unit 6 are fixed to the first surface 41 over substantially the entire length, they are less likely to be distorted by the weight of the first measurement unit 7 and the second measurement unit 8 that they support. Furthermore, because the first scanning unit 9 and the second scanning unit 10 that move the first measurement unit 7 and the second measurement unit 8 are also fixed to the same surface (first surface 41), positional deviation between the components is less likely to occur. Therefore, it is possible to control the positions of the first measurement unit 7 and the second measurement unit 8 with high precision, and measure the thickness of the object 15 with high precision.

[0036] The rigidity is improved by the plate-like plate 4, and therefore the measurement unit 2 can be made smaller and lighter.

[0037] The measuring unit 2 may further include a positioning portion provided on the first surface 41 for positioning the first guide portion 5 and the second guide portion 6. Since the positioning portion is provided on the first surface 41, the work of fixing the first guide portion 5 and the second guide portion 6 is facilitated, and the assembly of the measuring unit 2 is improved.

[0038] The positioning portion may also include a pin 45 inserted into a positioning hole 44 formed in the first surface 41. The positioning hole 44 can be formed at a specified position with high precision by NC machining or the like, and therefore, by fixing the first guide portion 5 and the second guide portion 6 while abutting them against the pin 45, positioning can be easily and accurately achieved.

[0039] Furthermore, the first guide unit 5 and the second guide unit 6 may be rails that are provided in contact with the pins 45. The rails can be positioned easily and accurately by contacting the pins 45. Therefore, there is no need to adjust the positions of the first measuring unit 7 and the second measuring unit 8 after they are attached to the first guide unit 5 and the second guide unit 6.

[0040] The measuring device may further include a driving device 11 fixed to the first surface 41 to move the first measuring unit 7 and the second measuring unit 8. By fixing the driving device 11 to the first surface 41 in the same way as the first guide unit 5 and the second guide unit 6, misalignment between the first measuring unit 7 and the second measuring unit 8 is less likely to occur, and the thickness of the object 15 to be measured can be measured with high accuracy.

[0041] The drive device 11 may further include a first belt 93 provided on one side of the long hole 43 and extending along a first direction, a first drive pulley 91 and a first driven pulley 92 that move the first belt 93, a second belt 103 provided on the other side of the long hole 43 and extending along the first direction, and a second drive pulley 101 and a second driven pulley 102 that move the second belt 103, and the drive device 11 may include a motor, and the output shaft 11a of the motor may be connected to the first drive pulley 91 and the second drive pulley 101.

[0042] Since the output shaft 11a of the drive device 11 is connected to the first drive pulley 91 and the second drive pulley 101, the first measuring unit 7 and the second measuring unit 8 can be moved by a single drive device 11. This allows for a reduction in size and cost by reducing the number of components included in the measurement unit 2. Furthermore, since the first measuring unit 7 and the second measuring unit 8 can be moved by simply controlling a single drive device 11, drive control can be simplified.

[0043] The measurement unit 2 may further include a control box 3 provided independently of the plate 4, and a control unit 30 housed in the control box 3 and controlling the movement of the first measurement unit 7 and the second measurement unit 8. By consolidating the components other than the mechanical elements for moving the first measurement unit 7 and the second measurement unit 8 inside the control box 3, the measurement unit 2 can be made smaller.

[0044] FIG. 5 is a diagram showing an example of installation of the thickness measuring device according to the first embodiment. In the example shown in FIG. 5, the object to be measured 15 is an electrode sheet. In the electrode sheet, for example, slurry is coated on both sides of an aluminum foil. The thickness of the object to be measured 15 is measured using the thickness measuring device 1 to confirm the basis weight (coating basis weight) of the slurry on the aluminum foil and whether the slurry is uniformly coated. When measuring the thickness of an aluminum foil coated with slurry, the emission unit, which is one of the first measuring unit 7 and the second measuring unit 8, serves as a radiation emission unit that emits radiation. In this case, the detection unit serves as a radiation detection unit that detects radiation.

[0045] The measurement unit 2 of the thickness measuring device 1 is attached inside a coating machine 13 that coats the aluminum foil with the slurry. The control box 3 of the thickness measuring device 1 is provided outside the coating machine 13.

[0046] A coating section 14 that coats the slurry is provided inside the coater 13. In the thickness measuring device 1, the measurement unit 2 is made compact, so it can be installed inside the coater 13, which has limited space. By providing the measurement unit 2 inside the coater 13, it becomes possible to measure the basis weight and the like immediately after the slurry is coated, and it becomes possible to quickly transport the slurry to the next process or to quickly rework the coating if there is a defect in the coating.

[0047] Furthermore, in the manufacturing process of the electrode sheet (the object to be measured 15), a drying process in which the slurry is dried in a drying path may be provided after the coating process in which the slurry is coated on aluminum foil. In this case, the drying path may be provided near the measurement unit 2. The interior of the drying path is heated to a high temperature to dry the slurry. As a result, high-temperature gas may leak from the drying path toward the measurement unit 2. Because high-temperature gas flows upward due to convection, the upper part of the plate 4 of the measurement unit 2 is more likely to become hotter than the lower part, which makes it easier for a temperature difference to occur between the top and bottom. Here, because the upper and lower parts of the plate 4 are formed with the same first surface 41, even if a temperature difference occurs, there is little difference in distortion between the upper and lower parts. Therefore, even if a drying path is provided nearby, the movement accuracy of the first measurement unit 7 and the second measurement unit 8, which move along the first guide unit 5 and the second guide unit 6 attached to the first surface 41, is prevented from being reduced by temperature.

[0048] The first guide unit 5 and the second guide unit 6 that guide the first measurement unit 7 and the second measurement unit 8 are not limited to rail members, and may be, for example, grooves formed on the first surface 41 of the plate 4. The grooves extend along the first direction and function as rails that guide the first measurement unit 7 and the second measurement unit 8. The grooves may or may not penetrate the plate 4.

[0049] Furthermore, the number of drive devices 11 is not limited to one, and separate drive devices may be provided for driving the first drive pulley 91 and the second drive pulley 101. Furthermore, the drive device 11 may include a linear motor without providing the first scanning unit 9 and the second scanning unit 10. In this case, the stator of the linear motor is fixed to the first surface 41 of the plate 4, and the first measuring unit 7 and the second measuring unit 8 are fixed to the mover. Furthermore, ball screws may be used instead of the first belt 93 and the second belt 103.

[0050] Furthermore, the plate 4 may be divided into multiple pieces, and the divided plate members may be connected together. Even if the plate 4 is divided into multiple pieces, the same effect as when the plate is formed from a single piece can be obtained by fixing the first guide portion 5 and the second guide portion 6 to the same first surface 41.

[0051] [Others] Some examples of combinations of the disclosed technical features are described below.

[0052] (1) A thickness measuring device comprising: a plate having a long hole extending in a first direction; a first guide portion provided on a first surface of the plate on one side of the long hole and extending along the first direction; a first measuring portion supported by the first guide portion and movable along the first direction; a second guide portion provided on the first surface on the other side of the long hole and extending along the first direction; and a second measuring portion supported by the second guide portion and movable along the first direction; the thickness measuring device measures the thickness of an object passing through the long hole and a gap between the first measuring portion and the second measuring portion.

[0053] (2) The thickness measuring device according to (1) above, further comprising a positioning section provided on the first surface for positioning the first guide section and the second guide section.

[0054] (3) The thickness measuring device according to (2) above, wherein the positioning portion includes a pin inserted into a positioning hole formed in the first surface.

[0055] (4) The thickness measuring device according to (3) above, wherein the first guide portion and the second guide portion are rails that are provided in contact with the pin.

[0056] (5) The thickness measuring device according to any one of (1) to (4) above, further comprising a driving device for moving the first measuring unit and the second measuring unit.

[0057] (6) A thickness measuring device as described in (5) above, further comprising: a first belt provided on one side of the elongated hole and extending along the first direction; a first drive pulley and a first driven pulley for moving the first belt; a second belt provided on the other side of the elongated hole and extending along the first direction; and a second drive pulley and a second driven pulley for moving the second belt, wherein the drive device includes a motor, and the output shaft of the motor is connected to the first drive pulley and the second drive pulley.

[0058] (7) A thickness measurement device described in any one of (1) to (6) above, further comprising a control box provided independently of the plate, and a control unit housed in the control box for controlling the movement of the first measurement unit and the second measurement unit.

[0059] (8) A thickness measuring device as described in (5) above, wherein the drive device includes a linear motor, the stator of the linear motor is fixed to the first surface, and the first measuring unit and the second measuring unit are fixed to the movable element of the linear motor.

[0060] (9) A thickness measurement device according to any one of (1) to (8) above, wherein one of the first measurement unit and the second measurement unit is a radiation emission unit that emits radiation, and the other is a detection unit that detects radiation.

[0061] (10) A thickness measuring device according to any one of (1) to (9) above, wherein the plate is divided into a plurality of pieces.

[0062] REFERENCE SIGNS LIST 1 Thickness measuring device 2 Measuring unit 3 Control box 3a Opening 30 Control unit 4 Plate 41 First surface 42 Second surface 43 Slot 44 Hole 45 Pin 5 First guide section 6 Second guide section 7 First measuring section 8 Second measuring section 9 First scanning unit 91 First driving pulley 92 First driven pulley 93 First belt 10 Second scanning unit 101 Second driving pulley 102 Second driven pulley 103 Second belt 11 Driving device 12 Frame 13 Coating machine 14 Coating section 15 Object to be measured

Claims

1. A thickness measuring device comprising: a plate having a slot extending in a first direction; a first guide member provided on a first surface of the plate on one side of the slot and extending along the first direction; a first measuring member supported by the first guide member and movable along the first direction; a second guide member provided on the first surface on the other side of the slot and extending along the first direction; and a second measuring member supported by the second guide member and movable along the first direction; and the thickness measuring device measures the thickness of an object passing through the slot and a gap between the first measuring member and the second measuring member.

2. A thickness measuring device according to claim 1, further comprising a positioning section provided on said first surface for positioning said first guide section and said second guide section.

3. The thickness measuring device according to claim 2, wherein the positioning portion includes a pin inserted into a positioning hole formed in the first surface.

4. A thickness measuring device according to claim 3, wherein said first guide portion and said second guide portion are rails that are provided in contact with said pin.

5. A thickness measuring device according to any one of claims 1 to 4, further comprising a drive device for moving the first measuring unit and the second measuring unit.

6. A thickness measuring device according to claim 5, further comprising: a first belt provided on one side of said elongated hole and extending along said first direction; a first drive pulley and a first driven pulley for moving said first belt; a second belt provided on the other side of said elongated hole and extending along said first direction; and a second drive pulley and a second driven pulley for moving said second belt, said drive device including a motor, the output shaft of said motor being connected to said first drive pulley and said second drive pulley.

7. A thickness measuring device as described in any one of claims 1 to 4, further comprising: a control box provided independently of the plate; and a control unit housed in the control box for controlling the movement of the first measuring unit and the second measuring unit.

8. A thickness measuring device according to claim 5, wherein the drive device includes a linear motor, a stator of the linear motor is fixed to the first surface, and the first measuring unit and the second measuring unit are fixed to a movable element of the linear motor.

9. A thickness measuring device according to any one of claims 1 to 4, wherein one of the first measuring unit and the second measuring unit is a radiation emitting unit that emits radiation, and the other is a detection unit that detects radiation.

10. A thickness measuring device according to any one of claims 1 to 4, wherein the plate is divided into a plurality of pieces.

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