Measuring device, measuring method, and measurement program

Abstract

To provide a measurement device, a method for measurement, and a measurement program that can secure a measurement accuracy of a thick measurement target.SOLUTION: A measurement device 10 includes: a measurement unit 20 having a radiation source 22 for emitting radiation to a measurement target 80 and a detector 24 for detecting radiation having passed through the measurement target 80 and outputting a detection signal; and a control unit 70 for calculating the thickness of the measurement target 80 on the basis of a sampling signal obtained by sampling the detection signal output from the detector 24 in the set upper limit of the range of sampling. The control unit 70 sets the upper limit of the sampling range on the basis of the thickness of the measurement target 80.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to a measuring device, a measuring method, and a measurement program.

Background Art

[0002] Conventionally, a basis weight measuring device for measuring the thickness of a sheet member has been known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is required to ensure measurement accuracy even when the measurement target becomes thick.

[0005] The present disclosure has been made in view of the above points, and an object thereof is to provide a measuring device, a measuring method, and a measurement program capable of ensuring the measurement accuracy of a thick measurement target.

Means for Solving the Problems

[0006] A measuring device according to some embodiments includes a measuring unit having a radiation source that emits radiation toward a measurement target and a detector that detects the radiation transmitted through the measurement target and outputs a detection signal, and a control unit that calculates the thickness of the measurement target based on a sampling signal obtained by sampling the detection signal output from the detector while setting an upper limit of a sampling range. The control unit sets the upper limit of the sampling range based on the thickness of the measurement target. By doing so, the change amount of the areal weight corresponding to one count of the discrete value converted by sampling becomes small. As a result, the measurement resolution of the areal weight becomes high.

[0007] In a measuring device according to an embodiment, the measuring unit may further include a driving unit that moves the radiation source and the detector. The control unit may move the radiation source and the detector by the driving unit so that the radiation source and the detector scan the measurement target. By doing so, the measuring device can scan the measurement target. As a result, the convenience of the measuring device is enhanced.

[0008] In a measuring device according to an embodiment, it may further include a housing that houses the measuring unit and a calibration sample installed in the housing. The control unit controls the driving unit so that the radiation source and the detector move to a position sandwiching the calibration sample during at least a part of the period when the measurement target does not exist between the radiation source and the detector, and may cause the detector to detect the radiation transmitted through the calibration sample. By doing so, the frequency of calibration work is increased. As a result, the measurement accuracy is improved.

[0009] In a measuring device according to an embodiment, the measuring unit may further include a sample insertion unit configured to be able to insert a calibration sample between the radiation source and the detector. The control unit controls the sample insertion unit so that the calibration sample is inserted between the radiation source and the detector during at least a part of the period when the measurement target does not exist between the radiation source and the detector, and may cause the detector to detect the radiation transmitted through the calibration sample. By doing so, the frequency of calibration work is increased. As a result, the measurement accuracy is improved.

[0010] In a measuring device according to an embodiment, the calibration sample may include at least a first calibration sample and a second calibration sample. The transmittance of radiation in the first calibration sample and the transmittance of radiation in the second calibration sample may be different from each other. The control unit may cause the detector to detect the radiation transmitted through at least one of the first calibration sample or the second calibration sample. By doing so, the calibration work can be easily performed. As a result, the measurement accuracy is improved.

[0011] In the measuring device according to one embodiment, the control unit may calculate the thickness of the measurement target based on a calibration curve that specifies the relationship between the thickness of the measurement target and the sampling signal. The calibration curve may be generated so as to correspond to each case where the upper limit of the sampling range is set to a different value. By doing so, the areal weight can be easily calculated. As a result, the convenience of the measuring device is enhanced.

[0012] Some measurement methods according to embodiments include a step of calculating the thickness of a measurement target based on a sampling signal obtained by sampling a detection signal of radiation transmitted through the measurement target with an upper limit of a sampling range set, and a step of setting the upper limit of the sampling range based on the thickness of the measurement target. By doing so, the change amount of the areal weight corresponding to one count of the discrete values converted by sampling becomes small. As a result, the measurement resolution of the areal weight is increased.

[0013] Some measurement programs according to embodiments cause a measuring device to execute a step of calculating the thickness of a measurement target based on a sampling signal obtained by sampling a detection signal of radiation transmitted through the measurement target with an upper limit of a sampling range set, and a step of setting the upper limit of the sampling range based on the thickness of the measurement target. By doing so, the change amount of the areal weight corresponding to one count of the discrete values converted by sampling becomes small. As a result, the measurement resolution of the areal weight is increased.

Advantages of the Invention

[0014] According to the measuring device, measurement method, and measurement program according to the present disclosure, the measurement accuracy of a thick measurement target can be ensured.

Brief Description of the Drawings

[0015]

Figure 1

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DETAILED DESCRIPTION OF THE INVENTION

[0016] (Comparative Example) As shown in FIG. 1, the measuring device 90 according to the comparative example includes a radiation source 91, a detector 92, a driving unit 93, and a housing 94. The measuring device 90 moves at least one of the housing 94 or the measurement object 95 so that the measurement object 95 is positioned between the radiation source 91 and the detector 92. Further, the measuring device 90 moves the radiation source 91 and the detector 92 to an arbitrary position of the measurement object 95 by the driving unit 93. The measuring device 90 emits radiation from the radiation source 91, detects the radiation transmitted through the measurement object 95 positioned between the radiation source 91 and the detector 92 with the detector 92, and calculates the thickness at an arbitrary position of the measurement object 95 based on the intensity of the detected radiation.

[0017] The transmittance of radiation in the measurement target 95 decreases as the measurement target 95 becomes thicker. When the intensity of the radiation emitted from the radiation source 91 is known, the transmittance of radiation in the measurement target 95 corresponds to the detection result of the intensity of the radiation transmitted through the measurement target 95. The thickness of the measurement target 95 is expressed as the weight per unit area (areal weight). The relationship between the areal weight corresponding to the thickness of the measurement target 95 and the radiation intensity transmitted through the measurement target 95 can be shown as the graph in FIG. 2. The horizontal axis represents the areal weight, and the vertical axis represents the radiation intensity. When the areal weight of the measurement target 95 is 0, that is, when the measurement target 95 does not exist between the radiation source 91 and the detector 92, the radiation intensity is represented as I0.

[0018] When the measuring device 90 is realized by a digital circuit, the measuring device 90 samples the detection signal of the radiation by the detector 92 and converts it into a discrete value of the radiation intensity. When the relationship between the areal weight and the radiation intensity is represented by the graph in FIG. 2, the measuring device 90 samples the radiation intensity detected by the detector 92 in the range where the radiation intensity is from 0 to I0, which is represented as SC, and converts it into a discrete value of the radiation intensity. The measuring device 90 calculates the areal weight of the measurement target 95 based on a table that associates the discrete value count of the radiation intensity transmitted through the measurement target 95 with the areal weight of the measurement target 95. The range in which the areal weight of the measurement target 95 can be calculated is the range where the areal weight corresponding to the range of the radiation intensity represented as SC is 0 or more, which is represented as MC.

[0019] The radiation intensity is sampled at a constant sampling interval. Therefore, the change amount of the radiation intensity when the discrete value of the radiation intensity changes by 1 count is constant regardless of the magnitude of the radiation intensity. On the other hand, the slope of the graph representing the relationship between the areal weight and the radiation intensity becomes gentler as the areal weight increases. In this case, the larger the areal weight of the measurement target 95, the larger the change amount of the areal weight when the discrete value of the radiation intensity changes by 1 count. Then, the measured value of the areal weight of the measurement target 95 in the measuring device 90 is calculated at wider intervals as the areal weight of the measurement target 95 increases. In other words, the resolution of the measurement of the areal weight decreases as the areal weight of the measurement target 95 increases.

[0020] The measuring device 90 is designed to be able to measure the areal weight with a resolution of 0.1% when the areal weight of the measurement target 95 is within the range of 0 to 1200 g / m 2 . Here, the areal weight of the electrode sheet used in the all-solid-state battery is about 2000 g / m 2 . Also, it is required to measure the areal weight of the electrode sheet used in the all-solid-state battery with a resolution of 0.1% (about 2 g / m 2 ).

[0021] However, in the electrode sheet of about 2000 g / m 2 , the transmittance of radiation is only about 0.1%. At this time, when the detection result of the transmitted radiation intensity is sampled by a 14-bit AD converter, the resolution of the areal weight corresponding to 1 count is about 10 g / m 2 . Then, the required resolution of 0.1% (about 2 g / m 2 ) cannot be obtained for the electrode sheet of about 2000 g / m 2 . Therefore, the measuring device 90 according to the comparative example may not be able to obtain a sufficiently high resolution when the measurement target 95 is thick.

[0022] Therefore, the present disclosure will describe a measuring device 10 (see FIGS. 3 to 5, etc.) that can ensure a high resolution even when measuring a thick sheet.

[0023] (Configuration example of the measuring device 10 according to the present embodiment) As shown in FIGS. 3 and 4, a measuring device 10 according to an embodiment of the present disclosure includes a measuring unit 20 and a housing 30. The housing 30 houses the measuring unit 20. The measuring unit 20 includes a radiation source 22 and a detector 24. The radiation source 22 is configured to emit radiation such as beta rays or X-rays. The detector 24 is configured to be able to detect the radiation emitted from the radiation source 22. The detector 24 outputs the detection result of the radiation as a detection signal. The detector 24 may be configured in various forms such as a dosimeter.

[0024] The measuring device 10 emits radiation from the radiation source 22 to the measurement target 80 located between the radiation source 22 and the detector 24, detects the radiation transmitted through the measurement target 80 with the detector 24, and measures the thickness of the measurement target 80 based on the detection result of the radiation. Assume that the measurement target 80 is a sheet-like object extending along the XY plane. The radiation source 22 and the detector 24 are arranged side by side with a predetermined interval in the Z-axis direction so that the measurement target 80 extending along the XY plane can enter between the radiation source 22 and the detector 24.

[0025] The measuring device 10 is configured to be able to change the positional relationship between the measuring unit 20 and the measurement target 80 along the XY plane in order to measure the thickness at any position of the measurement target 80 extending along the XY plane. In the present embodiment, the measuring unit 20 further includes a driving unit 26. The driving unit 26 is configured to move the radiation source 22 and the detector 24 in the X-axis direction. Also, assume that the measuring device 10 is configured to move the measurement target 80 in the Y-axis direction with respect to the housing 30. Thereby, the measuring unit 20 can move to any position of the measurement target 80 extending along the XY plane and can scan the measurement target 80. The measuring device 10 may be configured to move the housing 30 in the Y-axis direction instead of moving the measurement target 80. Since the measuring unit 20 can scan the measurement target 80, the convenience of the measuring device 10 is enhanced.

[0026] As shown in FIG. 5, the measuring device 10 further includes a control unit 70 and an interface 60. The control unit 70 controls each component of the measuring device 10 such as the measuring unit 20 or the interface 60. The control unit 70 may be configured to include a processor such as a CPU (Central Processing Unit). The control unit 70 may realize various functions of the measuring device 10 by executing a predetermined program.

[0027] The control unit 70 may include a storage unit. The storage unit may store various information used for the operation of the control unit 70, or a program or the like for realizing the functions of the control unit 70. The storage unit may function as a working memory of the control unit 70. The storage unit may be composed of, for example, a semiconductor memory or the like. The storage unit may be configured separately from the control unit 70.

[0028] The interface 60 may include a communication interface such as a LAN (Local Area Network). The interface 60 may be communicably connected to an external device by wire or wirelessly. The interface 60 is not limited thereto and may include various other communication devices.

[0029] The interface 60 may include a display device. The display device may include various displays such as a liquid crystal display. The interface 60 may include an audio output device such as a speaker. The interface 60 is not limited thereto and may include various other output devices.

[0030] The interface 60 may include an input device for receiving an input from a user. The input device may include, for example, a keyboard or physical keys, or a pointing device such as a touch panel or touch sensor or mouse. The input device is not limited to these examples and may include various other devices.

[0031] (Operation example of the measuring device 10 according to this embodiment) The transmittance of radiation in the measurement target 80 decreases as the measurement target 80 becomes thicker. The control unit 70 of the measuring device 10 can calculate the transmittance of radiation in the measurement target 80 based on the intensity of the radiation emitted from the radiation source 22 and the intensity of the radiation detected by the detector 24. The thicker the measurement target 80, the lower the transmittance of radiation in the measurement target 80. The control unit 70 can calculate the thickness of the measurement target 80 from the intensity of the radiation detected by the detector 24 based on the relationship between the thickness of the measurement target 80 and the transmittance of radiation in the measurement target 80.

[0032] The thickness of the measurement target 80 is expressed as the weight per unit area. The weight per unit area is also referred to as the areal weight. When the radiation intensity emitted from the radiation source 22 is known, the transmittance of the radiation is expressed as the radiation intensity transmitted through the measurement target 80. Assume that the relationship between the areal weight of the measurement target 80 and the radiation intensity transmitted through the measurement target 80 is shown as the graph in FIG. 6. The horizontal axis represents the areal weight, and the vertical axis represents the radiation intensity. When the areal weight of the measurement target 80 is 0, that is, when the measurement target 80 does not exist between the radiation source 22 and the detector 24, the radiation intensity is represented as I0. The radiation is absorbed or scattered not only by the measurement target 80 but also by the air. Therefore, the radiation intensity I0 when the measurement target 80 does not exist is the intensity of the radiation transmitted through the air layer existing between the radiation source 22 and the detector 24.

[0033] The control unit 70 samples the detection signal obtained as a result of detecting the radiation intensity by the detector 24 and converts it into a discrete value. In the present embodiment, assume that the control unit 70 includes a 14-bit AD converter. The 14-bit AD converter samples the detection signal of the detector 24 and converts it into any one of 16384 (2 14 to the power of 14) discrete values from 0 count to 16383 count. Each discrete value is a value representing the interval of the radiation intensity including that discrete value. The AD converter converts the value of the radiation intensity input as the detection signal into a discrete value representing the interval in which the radiation intensity is included. The number of bits of the AD converter is not limited to 14 bits and may be 13 bits or less or 15 bits or more. The control unit 70 is not limited to the AD converter as a configuration for sampling the detection signal and may include various other circuits or elements.

[0034] The control unit 70 obtains the relationship between the areal weight of the measurement target 80 and the count of discrete values converted from the detection signal of the detector 24. The relationship between the areal weight of the measurement target 80 and the count is generated by sampling the radiation intensity on the vertical axis and converting it into discrete values in the relationship illustrated as a graph in FIG. 6. The relationship between the areal weight of the measurement target 80 and the count may be represented by a calibration curve. The control unit 70 can easily calculate the areal weight by converting the count of discrete values obtained by sampling and converting the radiation intensity using the calibration curve into the areal weight of the measurement target 80. As a result, the convenience of the measuring device 10 is enhanced.

[0035] The calibration curve may be represented as an approximation formula including various mathematical formulas such as an exponential function or a polynomial. The calibration curve may be represented by approximating the curve with a broken line including a plurality of line segments. The broken line approximating the calibration curve can be specified by the combination of the value of the areal weight and the value of the radiation intensity at the nodes where the plurality of line segments included in the broken line are connected. For example, as shown in Table 1, 64 nodes from N - 3 to N + 60 corresponding to the start points or end points of 63 broken lines approximating the calibration curve can be specified. The number of nodes may be 63 or less, or may be 65 or more.

Table 1

[0036] In the calibration curve in which the areal weight and the count are associated with each other, the smaller the change amount of the radiation intensity corresponding to 1 count of the discrete value of the radiation intensity, the smaller the change in the areal weight corresponding to 1 count of the discrete value of the radiation intensity. The smaller the change in the areal weight corresponding to 1 count of the discrete value of the radiation intensity, the higher the resolution at which the control unit 70 can calculate the areal weight. The change amount of the radiation intensity corresponding to 1 count of the discrete value of the radiation intensity is determined by the width of the radiation intensity in the interval represented by each discrete value, which is used when sampling the detection signal of the detector 24. Therefore, the control unit 70 can calculate the areal weight with high resolution by narrowing the width of the radiation intensity in the interval represented by each discrete value.

[0037] In the measuring device 10 according to the present embodiment, the control unit 70 makes the upper limit of the intensity range of the detection signal to be sampled lower than the intensity of the detection signal corresponding to the radiation intensity I0 when the measurement target 80 does not exist. By lowering the upper limit of the intensity range of the detection signal to be sampled, the sampling range becomes narrower. When the control unit 70 samples using a 14-bit AD converter and converts the detection signal into discrete values from 0 count to 16383 counts, the narrower the sampling range, the narrower the width of the section including one count of discrete values.

[0038] On the other hand, when the intensity of the detection signal corresponding to the intensity of the radiation transmitted through the measurement target 80 is outside the sampling range, the areal weight of the measurement target 80 cannot be calculated using the calibration curve. Therefore, the control unit 70 sets the upper limit of the intensity range of the detection signal to be sampled to be equal to or higher than the intensity of the detection signal corresponding to the intensity of the radiation transmitted through the measurement target 80. By doing so, the control unit 70 can measure the areal weight of the measurement target 80 while increasing the resolution of the areal weight of the measurement target 80.

[0039] In the graph of FIG. 6, the radiation intensity corresponding to the upper limit of the intensity range of the detection signal to be sampled is represented as I1. In this case, the control unit 70 samples the detection signal in the intensity range of the detection signal corresponding to the radiation intensity range from 0 to I1 and converts it into discrete values. The radiation intensity range to be sampled from 0 to I1 is represented as SR. The areal weight corresponding to the radiation intensity I1 is represented as W1. When the radiation intensity range to be sampled is from 0 to I1, the control unit 70 can calculate the areal weight using the calibration curve in the range where the areal weight is W1 or more. The range in which the areal weight can be calculated when the radiation intensity to be sampled is limited to the range represented by SR is represented as MR. Conversely, when the control unit 70 lowers the upper limit of the radiation intensity range to be sampled to I1, it can exclude from the calibration curve the range where the areal weight is less than W1 (outside the range represented as MR) that does not include the areal weight of the measurement target 80.

[0040] The range represented by SR is narrower than the range in which the radiation intensity is from 0 to I0. When converting the range represented by SR into 16384 discrete values using a 14-bit AD converter, the width of each interval including each discrete value is narrower than the width of each interval including each discrete value when converting the range in which the radiation intensity is from 0 to I0 into 16384 discrete values. In other words, when the range represented by SR is the sampling target, the change amount of the area weight when the discrete value changes by 1 count is smaller than when the range in which the radiation intensity is from 0 to I0 is the sampling target. As a result, the control unit 70 can increase the resolution of the measurement of the area weight by narrowing the range to be sampled to the range represented by SR.

[0041] It is assumed that the measuring device 10 measures a measurement target 80 having a W larger than W1 as the value of the area weight. T Assume that the measuring device 10 measures a measurement target 80 having a W larger than W1 as the value of the area weight. When the value of the area weight is W T the radiation intensity in this case is I T which is represented. The control unit 70 narrows the range to be sampled to the range represented by SR. In this case, when converting the radiation intensity I T into discrete values, the difference between each discrete value becomes smaller. By the difference between each discrete value becoming smaller, the difference in the area weight corresponding to each discrete value becomes smaller. As a result, the resolution of the area weight is increased. Also, by the difference between each discrete value becoming smaller, the difference (quantization error) between the radiation intensity I T and the discrete value becomes smaller. As a result, the measurement accuracy of the area weight is improved. As described above, the measuring device 10 according to the present embodiment can increase the resolution of the measurement of the measurement target 80 having a large area weight such as W T and improve the measurement accuracy.

[0042] <Example> When the measuring device 10 samples the range in which the radiation intensity is from 0 to I0, it is assumed that the measuring device 10 is designed such that the area weight of the measurement target 80 can be measured with a resolution of 0.1% when it is within the range of 0 to 1200 g / m 2 In the measuring device 10 designed in this way, when the area weight is about 2000 g / m2 The electrode sheet used in the all-solid-state battery, which is out of the measurement range. Therefore, the control unit 70 of the measuring device 10 sets the upper limit of the range to be sampled to the radiation intensity corresponding to the areal weight of 800 g / m 2 When this is done, the control unit 70 can measure the electrode sheet used in the all-solid-state battery with an areal weight of about 2000 g / m 2 with a resolution of 0.1%. When the control unit 70 knows that the areal weight of the measurement target 80 is greater than 2000 g / m 2 it may set the upper limit of the range to be sampled to the radiation intensity corresponding to the areal weight of 2000 g / m 2 when it is known.

[0043] <Example of the flowchart of the measurement procedure> The control unit 70 of the measuring device 10 may execute the procedure illustrated in the flowchart of FIG. 7 as the measurement method. The procedure illustrated in the flowchart of FIG. 7 may be realized as a measurement program to be executed by a processor constituting the control unit 70. The measurement program may be stored in a non-transitory computer-readable medium such as an electromagnetic storage medium.

[0044] The control unit 70 acquires the thickness range of the measurement target 80 (step S1). For example, the control unit 70 may receive an input specifying the thickness range of the measurement target 80 from the user by the input device of the interface 60. The control unit 70 may acquire the thickness range of the measurement target 80 from an external device by the communication device of the interface 60.

[0045] The control unit 70 sets the upper limit of the sampling range (step S2). Specifically, the control unit 70 may calculate the radiation intensity corresponding to the lower limit of the thickness range of the measurement target 80 and set the upper limit of the sampling range to the calculated radiation intensity, or may set the upper limit of the sampling range to a radiation intensity greater than the calculated radiation intensity.

[0046] The control unit 70 acquires a calibration curve within the sampling range with the upper limit set (step S3). Specifically, the control unit 70 acquires a calibration curve that associates the area weight with each discrete value included in the sampling range with the upper limit set. The control unit 70 may set the upper limit of the sampling range in the procedure of step S2 so as to match a calibration curve prepared in advance. That is, the control unit 70 may assume a plurality of candidate values as the upper limit of the sampling range and acquire a calibration curve when each candidate value is set as the upper limit of the sampling range. The calibration curve may be generated to correspond to each case where the upper limit of the sampling range is set to a different value.

[0047] The control unit 70 acquires a sampling signal (step S4). Specifically, the control unit 70 moves the measurement unit 20 to the measurement position of the measurement target 80. The control unit 70 causes radiation to be emitted from the radiation source 22 at the measurement position and causes the radiation transmitted through the measurement target 80 to be detected by the detector 24. The control unit 70 may acquire a detection signal from the detector 24 and generate a sampling signal representing a count converted into discrete values by sampling the detection signal. The control unit 70 may acquire the sampling signal from an AD converter that samples the detection signal.

[0048] The control unit 70 calculates the thickness (area weight) of the measurement target 80 (step S5). Specifically, the control unit 70 calculates the value of the area weight corresponding to the count represented by the sampling signal based on the calibration curve. The control unit 70 may convert the value of the area weight into the value of the thickness of the measurement target 80. The control unit 70 may display the calculated value of the area weight or the value of the thickness of the measurement target 80 on the display device of the interface 60 to notify the user. After executing the procedure of step S5, the control unit 70 ends the execution of the procedure of the flowchart in FIG. 7.

[0049] (Example of the operation of calibrating the measuring device 10) The measuring device 10 further includes a calibration sample 40. The control unit 70 causes the radiation source 22 to emit radiation and causes the detector 24 to detect the radiation transmitted through the calibration sample 40 in a state where the calibration sample 40 is positioned between the radiation source 22 and the detector 24. The control unit 70 may sample the detection result of the detector 24, convert it into a discrete value, and perform calibration by associating the areal weight of the calibration sample 40 with the converted discrete value. The control unit 70 may correct the calibration curve based on the measurement result of the calibration sample 40.

[0050] As shown in FIGS. 3 and 4, the calibration sample 40 may be arranged in the housing 30. The calibration sample 40 may be arranged so as not to overlap the measurement target 80 in a plan view of the measurement target 80 (when the measurement target 80 is viewed in the Z-axis direction).

[0051] The control unit 70 controls the drive unit 26 so that the radiation source 22 and the detector 24 move to positions sandwiching the calibration sample 40 at least during a part of the period when the measurement target 80 does not exist between the radiation source 22 and the detector 24, and may cause the detector 24 to detect the radiation transmitted through the calibration sample 40. By doing so, the measuring device 10 can easily measure the calibration sample 40 and execute the calibration operation by moving the radiation source 22 and the detector 24 along the XY plane.

[0052] In the configuration illustrated in FIGS. 3 and 4, the control unit 70 may move the measurement unit 20 to the calibration sample 40 and execute the calibration operation each time the measurement unit 20 scans the measurement target 80 once in the X-axis direction. By doing so, the frequency of the calibration operation can be easily increased. As a result, the measurement accuracy can be improved.

[0053] <Example of flowchart of calibration curve generation procedure> The control unit 70 of the measuring device 10 may generate a calibration curve using the calibration sample 40. The control unit 70 may execute the procedure illustrated in the flowchart of FIG. 8 as a method for generating the calibration curve. The procedure illustrated in the flowchart of FIG. 8 may be realized as a calibration curve generation program for causing the processor constituting the control unit 70 to execute. The calibration curve generation program may be stored in a non-transitory computer-readable medium such as an electromagnetic storage medium.

[0054] The control unit 70 assays the sample (step S11). Specifically, the control unit 70 assays the value of the areal weight of the calibration sample 40 used for creating the calibration curve. The control unit 70 may assay the value of the areal weight of each of the plurality of calibration samples 40.

[0055] The control unit 70 acquires a detection signal that has detected the radiation transmitted through the calibration sample 40 (step S12). The control unit 70 may acquire a detection signal for each of the plurality of calibration samples 40. The control unit 70 executes an operation for creating the calibration curve (step S13). Specifically, the control unit 70 samples the detection signal that has detected the radiation transmitted through the calibration sample 40 and converts it into discrete values. The control unit 70 creates a calibration curve by associating the count of the converted discrete values with the areal weight of the calibration sample 40. When the control unit 70 has acquired detection signals for the plurality of calibration samples 40, the control unit 70 creates a calibration curve by associating the count of the discrete values obtained by sampling and converting the detection signal of each calibration sample 40 with the areal weight of each calibration sample 40.

[0056] The control unit 70 determines whether the approximation error of the created calibration curve is equal to or greater than the determination value (step S14). Specifically, the control unit 70 calculates the error between the created calibration curve and the calibration curve that should be theoretically obtained as the approximation error. The control unit 70 may calculate the difference between the count associated with an arbitrary area weight value in the created calibration curve and the count associated with the arbitrary area weight in the theoretical calibration curve, and compare the calculated difference with the determination value. The control unit 70 may calculate the difference between the count associated with each of a plurality of area weight values in the created calibration curve and the count associated with the area weight in the theoretical calibration curve. When the difference between the count associated with one or more area weight values in the created calibration curve and the count associated with the area weight in the theoretical calibration curve is equal to or greater than the determination value, the control unit 70 may determine that the approximation error of the created calibration curve is equal to or greater than the determination value. When the difference between the count associated with a predetermined number or more of area weight values in the created calibration curve and the count associated with the area weight in the theoretical calibration curve is equal to or greater than the determination value, the control unit 70 may determine that the approximation error of the created calibration curve is equal to or greater than the determination value. When the difference between the count associated with all area weight values used for the determination in the created calibration curve and the count associated with the area weight in the theoretical calibration curve is equal to or greater than the determination value, the control unit 70 may determine that the approximation error of the created calibration curve is equal to or greater than the determination value.

[0057] When the approximation error of the created calibration curve is equal to or greater than the determination value (step S14: YES), the control unit 70 returns to the procedure of step S11 and creates the calibration curve again.

[0058] When the approximation error of the created calibration curve is not greater than the determination value (step S14: YES), that is, when the approximation error of the created calibration curve is less than the determination value, the control unit 70 executes a sample test (step S15). Specifically, as the sample test, the control unit 70 may measure the calibration sample 40 having a known area weight by applying the created calibration curve. The control unit 70 may measure each of the calibration samples 40 having different area weights. Further, the control unit 70 may perform the measurement in a state where no calibration sample 40 exists between the radiation source 22 and the detector 24, that is, in a state where only air exists between the radiation source 22 and the detector 24. The control unit 70 may perform the measurement with a shutter that blocks radiation placed between the radiation source 22 and the detector 24. The control unit 70 may measure the calibration sample 40 at a predetermined cycle.

[0059] The control unit 70 determines whether the created calibration curve has passed the sample test (step S16). Specifically, the control unit 70 may determine that the sample test has passed when the difference between the measured value of the area weight obtained by measuring the calibration sample 40 having a known area weight by applying the created calibration curve and the known area weight is less than the determination value. The control unit 70 may determine that the sample test has passed when the count of the discrete values obtained by converting the detection signal in a state where only air exists between the radiation source 22 and the detector 24 reaches the maximum. The control unit 70 may also determine that the sample test has passed when the count of the discrete values obtained by converting the detection signal in a state where a shutter is inserted between the radiation source 22 and the detector 24 becomes zero. The control unit 70 may determine that the created calibration curve has passed the sample test when all of a plurality of test items have passed.

[0060] When the created calibration curve fails the sample test (step S16: NO), the control unit 70 returns to the procedure of step S11 and creates the calibration curve again. When the created calibration curve passes the sample test (step S16: YES), the control unit 70 adopts the created calibration curve and ends the execution of the procedure of the flowchart in FIG. 8.

[0061] <Another configuration example of calibration sample 40> As shown in FIGS. 9 and 10, the measurement unit 20 may include a calibration sample 40. The measurement unit 20 may include a sample insertion unit 50 that inserts and removes the calibration sample 40 between the radiation source 22 and the detector 24. In FIG. 9, the sample insertion unit 50 is configured to be insertable between the radiation source 22 and the detector 24 by sliding the calibration sample 40 in the X-axis direction. In FIG. 10, the sample insertion unit 50 is configured to be insertable between the radiation source 22 and the detector 24 by rotating the calibration sample 40. In FIGS. 9 and 10, the calibration sample 40 represented by the solid line is in a state where it is not inserted between the radiation source 22 and the detector 24. The calibration sample 40 represented by the two-dot chain line is in a state where it is inserted between the radiation source 22 and the detector 24. The sample insertion unit 50 may be configured to include, for example, a motor or may be configured to include various other actuators. The sample insertion unit 50 is configured not to collide with the measurement object 80 when the measurement unit 20 moves to the measurement object 80. The sample insertion unit 50 may retract the calibration sample 40 to a position shifted in the Z-axis direction from the surface into which the measurement object 80 is inserted while the measurement unit 20 is measuring the measurement object 80.

[0062] The control unit 70 controls the sample insertion unit 50 so that the calibration sample 40 is inserted between the radiation source 22 and the detector 24 during at least a part of the period when the measurement object 80 does not exist between the radiation source 22 and the detector 24, and the detector 24 may detect the radiation transmitted through the calibration sample 40. By doing so, the frequency of the calibration operation can be easily increased. As a result, the measurement accuracy can be improved.

[0063] As shown in FIGS. 11 and 12, the calibration sample 40 may include a first calibration sample 41, a second calibration sample 42, or a third calibration sample 43. The radiation transmittance in the first calibration sample 41, the radiation transmittance in the second calibration sample 42, and the radiation transmittance in the third calibration sample 43 may be different from each other.

[0064] In FIG. 11, the sample insertion unit 50 is configured such that by sliding the calibration sample 40 including the first calibration sample 41 and the second calibration sample 42 in the X-axis direction, one of the first calibration sample 41 or the second calibration sample 42 can be inserted between the radiation source 22 and the detector 24. In FIG. 12, the sample insertion unit 50 is configured such that by rotating the calibration sample 40 including the first calibration sample 41, the second calibration sample 42, and the third calibration sample 43, one of the first calibration sample 41, the second calibration sample 42, or the third calibration sample 43 can be inserted between the radiation source 22 and the detector 24. That is, the calibration sample 40 is configured to be switchable. In FIGS. 11 and 12, the first calibration sample 41, the second calibration sample 42, or the third calibration sample 43 represented by the solid line is in a state of not being inserted between the radiation source 22 and the detector 24. The first calibration sample 41, the second calibration sample 42, or the third calibration sample 43 represented by the dashed-dotted line is in a state of being inserted between the radiation source 22 and the detector 24.

[0065] Even when the calibration sample 40 is installed in the housing 30, the calibration sample 40 may be configured to be switchable among a plurality of calibration samples 40 having different areal weights.

[0066] By configuring the calibration sample 40 to be switchable, the calibration operation of the measuring device 10 can be easily performed. As a result, the measurement accuracy can be improved. The sample insertion unit 50 may be configured to include a shutter that blocks radiation. By doing so, the calibration sample 40 and the shutter can be integrated. As a result, even when the measurement unit 20 includes the calibration sample 40, it is not likely to become large.

[0067] As described above, the embodiments according to the present disclosure have been described with reference to the drawings. However, the specific configuration is not limited to this embodiment, and various modifications within the scope not departing from the gist of the present disclosure are also included.

Description of Reference Numerals

[0068] 10 Measuring device 20 Measuring unit (22: line source, 24: detector, 26: drive unit) 30 Housing 40 Calibration sample (41 - 43: first - third calibration samples) 50 Sample insertion part 60 Interface 70 Control unit 80 Object to be measured

Claims

1. A measuring unit having a radiation source that emits radiation toward a measurement target and a detector that detects the radiation transmitted through the measurement target and outputs a detection signal; A control unit that calculates the thickness of the measurement target based on a sampling signal obtained by setting an upper limit of a sampling range indicating an intensity range of a detection signal to be sampled and sampling when converting the detection signal output from the detector into discrete values; Comprising; The control unit sets the upper limit of the sampling range based on the lower limit of the thickness range of the measurement target. A measuring device.

2. The measuring unit further has a driving unit that moves the radiation source and the detector; The control unit moves the radiation source and the detector by the driving unit so that the radiation source and the detector scan the measurement target. The measuring device according to claim 1.

3. Further comprising a housing that houses the measuring unit and a calibration sample installed in the housing; The control unit controls the driving unit so that the radiation source and the detector move to a position sandwiching the calibration sample during at least a part of a period when the measurement target does not exist between the radiation source and the detector, and causes the detector to detect the radiation transmitted through the calibration sample. The measuring device according to claim 2.

4. The measuring unit further has a sample insertion unit configured to be able to insert a calibration sample between the radiation source and the detector; The control unit controls the sample insertion unit so that the calibration sample is inserted between the radiation source and the detector during at least a part of a period when the measurement target does not exist between the radiation source and the detector, and causes the detector to detect the radiation transmitted through the calibration sample. The measuring device according to any one of claims 1 to 3.

5. The calibration sample includes at least a first calibration sample and a second calibration sample; The radiation transmittance in the first calibration sample is different from the radiation transmittance in the second calibration sample; The control unit causes the detector to detect the radiation transmitted through at least one of the first calibration sample and the second calibration sample. The measuring device according to claim 3 or 4.

6. The control unit calculates the thickness of the measurement target based on a calibration curve that specifies the relationship between the thickness of the measurement target and the sampling signal. The calibration curve is generated so as to correspond to each case where the upper limit of the sampling range is set to a different value, the measuring apparatus according to any one of claims 1 to 5.

7. When sampling a detection signal of radiation that has passed through a measurement target and converting it into discrete values, a step of calculating the thickness of the measurement target based on a sampling signal obtained by setting and sampling an upper limit of a sampling range indicating an intensity range of the detection signal to be sampled; A step of setting the upper limit of the sampling range based on a lower limit of the thickness range of the measurement target A measurement method comprising:

8. When sampling a detection signal of radiation that has passed through a measurement target and converting it into discrete values, a step of calculating the thickness of the measurement target based on a sampling signal obtained by setting and sampling an upper limit of a sampling range indicating an intensity range of the detection signal to be sampled; A step of setting the upper limit of the sampling range based on a lower limit of the thickness range of the measurement target A measurement program for causing a measuring apparatus to execute.

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