JP2019060829A - Terahertz wave transmission measuring system and terahertz wave transmission measuring method - Google Patents

Abstract

To provide a technique of properly calibrating element difference among a plurality of detection elements that detect terahertz waves.SOLUTION: A storage unit 62 stores strength when an oscillator 52 is off (no transmission strength A0), strength when the oscillator 52 is on (all transmission strength A100), and transmission strength A5, A30, A58, A70 of terahertz waves that have passed through calibration samples 70a-70d (transmission rate 5%, 30%, 58%, 70%). A γ value determination unit 633 determines a γ value for γ correction in which measured transmission rates obtained from the transmission strength A5, A30, A58, A70 are made proximate to the transmission rates of the calibration samples 70a-70d for each detection element 540. A correction unit 637 performs γ correction on the strength detected by the plurality of detection elements 540 by the γ values of the respective detection devices 540.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a technique for measuring terahertz waves transmitted through an inspection object.

  A terahertz wave, which is an electromagnetic wave in a frequency band of 0.03 to 10 THz, is located in a frequency band intermediate between visible light and radio waves, and has both straightness of light and transparency of radio waves.

  Patent Document 1 proposes a foreign matter inspection system for displaying an image of the intensity distribution of terahertz waves transmitted through a sample. In this system, as terahertz wave detection elements, 1024 elements having a response speed of 25 ps at room temperature are arranged in 32 × 32 in two dimensions. Then, it is disclosed to display an image of a 4 cm square sample in about 0.5 seconds.

  Further, Patent Document 2 proposes using a terahertz wave to analyze a material whose transmission measurement is difficult with visible light, such as CCM (Catalyst Coated Membrane) of a fuel cell. Specifically, the amount of supported platinum catalyst in the CCM catalyst coating layer is calculated by using the high correlation between the transmittance of the terahertz wave and the amount of supported platinum catalyst in the coated catalyst layer. Is described.

  By the way, when acquiring the terahertz wave transmittance distribution in a sample using one terahertz wave source and a plurality of terahertz wave detection elements as in Patent Document 1, the position and incident intensity of each terahertz wave detection element with respect to the terahertz wave source Regardless, it is desirable that the same position of the same sample be detected as the same transmittance. Therefore, in general, the terahertz wave intensity obtained with the terahertz wave source off (0% transmittance) and the terahertz obtained with the terahertz wave source on (100% transmittance) for each of the plurality of terahertz wave detection elements. A technique is used to measure the wave intensity and perform linear correction with these values.

  Further, in a photoelectric conversion element such as a CCD, it is generally known that approximation by the γ characteristic of the following equation (1) is effective as an output value with respect to an input value (for example, Patent Document 3). It is considered effective to use γ correction also in the terahertz wave detection element.

x ′ = a × (x / a) ^{1 / γ} . . . (1)

  In equation (1), x 'is the output value, x is the input value, and a is the maximum value of the output value.

International Publication No. 2013/096805 JP, 2016-151562, A JP, 2014-183206, A

  However, in an apparatus that performs transmittance measurement using continuous terahertz waves, a plurality of terahertz wave detection elements may not be arranged at the same distance with respect to the terahertz wave source. In this case, since the intensity difference of the terahertz wave becomes large at each position of the terahertz wave detection element, the γ value becomes relatively large when attempting to reduce the inter-element intensity difference by the γ correction. However, when the γ value is increased, the transmitted terahertz intensity value after γ correction increases as the transmitted terahertz intensity decreases (that is, as the transmittance of the sample decreases). As a result, the transmittance may be calculated larger than the actual value, which may make it difficult to properly analyze the sample.

  Therefore, an object of the present invention is to provide a technique for properly calibrating the instrumental difference between a plurality of detection elements for detecting a terahertz wave.

  In order to solve the above-mentioned subject, the 1st mode is a terahertz wave penetration measurement system which measures intensity of a terahertz wave which penetrated measurement object, and it is an oscillator which oscillates terahertz wave, and a plurality of detections which detect terahertz wave A detector having an element, a control unit for controlling on / off of the oscillation of the terahertz wave in the oscillator, a first calibration sample having a first transmittance characteristic with respect to the terahertz wave, and the first calibration sample Between the oscillator and the detector, for each of the sample holding portion that holds the relative movement with respect to the plurality of detection elements, and the detection element (A) a state in which the terahertz wave is not oscillated from the oscillator At each of the detection elements, and (B) each of the detection elements is detected in a state where the terahertz wave is oscillated from the oscillator (B). Total transmitted intensity, which is the intensity to be detected, and (C) the intensity detected by each of the detection elements when the terahertz wave passes through the first calibration sample in a state where the terahertz wave is oscillated from the oscillator. The detection element based on an intensity storage unit for storing a first transmission intensity, a minimum value of the non-transmission intensities of the detection elements, and a maximum value of the total transmission intensities of the detection elements A normalized portion that normalizes each of the non-transmission intensity, the total transmission intensity, and the first transmission intensity, and an actually measured first transmittance determined from the normalized first transmission intensity for each detection element A γ value determination unit that determines a γ value to be approximated to the first transmittance by γ correction, and a correction unit that corrects the intensity detected by each of the detection elements based on the γ value.

  A second aspect is the terahertz wave transmission measurement system according to the first aspect, further comprising a second calibration sample having a characteristic of a second transmittance different from the first transmittance with respect to the terahertz wave, The sample holder can hold the second calibration sample, and the intensity storage unit detects (D) when the terahertz wave passes through the second calibration sample for each of the detection elements. The second transmission intensity is stored, the normalization unit further normalizes the second transmission intensity, and the γ value determination unit is configured to calculate the first transmittance and the second transmittance normalized for each of the detection elements. [2] A γ value that approximates the first transmittance and the second transmittance by γ correction is obtained.

  A third aspect is the terahertz wave transmission measurement system according to the second aspect, wherein the first and second calibration samples are silicon substrates having different sheet resistance values.

  A fourth aspect is a terahertz wave transmission measurement system, wherein one of the plurality of detection elements is a reference detection element, and the first transmittance of the first sample is a transmittance that is transmitted through the first sample. It is determined based on the intensity when the terahertz wave is measured by the reference detection element.

  A fifth aspect is the terahertz wave transmission measurement system according to any one of the first aspect to the fourth aspect, obtained by performing γ correction on the total transmission intensity with the γ value from a predetermined reference value for each detection element. And an intensity difference correction value acquiring unit for acquiring an intensity difference correction value for each detection element by subtracting the corrected total transmission intensity, and the correction unit further includes the terahertz wave detected by each of the plurality of detection elements. A correction is performed to add the intensity difference correction value to the intensity of.

  A sixth aspect is the terahertz wave transmission measurement system according to any one of the first aspect to the fifth aspect, wherein the plurality of detection elements include a detection element group arranged at a predetermined pitch in the first direction. And the first calibration sample has a width dimension shorter than the widths of both ends of the detection element group, and the calibration sample holder can move the first calibration sample along the first direction. Hold on.

  A seventh aspect is a terahertz wave transmission measurement method in which a plurality of detection elements detect a terahertz wave oscillated from an oscillator and transmitted through an object to be measured, and (a) for each of the plurality of detection elements (A) the oscillator Non-transmission intensity which is the intensity detected by each of the detection elements in a state where the terahertz wave is not oscillated, and (B) total transmission which is an intensity detected by each of the detection elements in a state where the terahertz wave is oscillated from the oscillator An intensity, and (C) a first transmission intensity which is an intensity detected by each of the detection elements when the terahertz wave transmits the first calibration sample in a state where the terahertz wave is oscillated from the oscillator; (B) based on the minimum value among the non-transmission intensities of each of the detection elements and the maximum value among the total transmission intensities of each detection element; A step of normalizing the non-transmission intensity, the total transmission intensity and the first transmission intensity of each of the elements; and (c) the first transmittance normalized in the step (b) for each detection element To determine the γ value that approximates the measured first transmittance to the first transmittance by γ correction, and (d) the intensity detected by each of the detection elements as the γ value of each of the detection elements And correcting based on the information.

  According to the terahertz wave transmission measurement system of the first aspect, for each detection element, the γ value of γ correction for determining the actually measured first transmittance obtained by actual measurement to the first transmittance of the calibration sample is determined. The instrumental error between the plurality of detection elements can be properly calibrated by performing γ correction on the intensity detected by each detection element with the γ value.

  According to the terahertz wave transmission measurement system of the second aspect, since a plurality of calibration samples having different transmittances are used to determine the γ value, it is possible to determine the more optimum γ value than one case. .

  According to the terahertz wave transmission system of the third aspect, the transmittance of the terahertz wave can be changed relatively easily by processing the silicon substrate so that the sheet resistance value is different. Further, since the transmittance can be made uniform over the surface, it becomes possible to measure the terahertz wave transmitted through the calibration sample at the same time for two or more detection elements.

  According to the terahertz wave transmission measurement system of the fourth aspect, the instrumental error between the plurality of detection elements can be calibrated according to the reference detection element.

  According to the terahertz wave transmission measurement system of the fifth aspect, a difference in detection intensity for the terahertz wave may occur based on the difference in the relative position of each detection element with respect to the oscillator. Therefore, the difference in relative position between the detection elements is performed by performing correction in which the intensity difference correction value, which is the difference value between the predetermined reference value and the total transmission intensity after γ correction, is added to the intensity detected by each detection element. The detection intensity error based on can be reduced.

  According to the terahertz wave transmission measurement system of the sixth aspect, the calibration sample holder holds the first calibration sample movably along the first direction, so the first calibration sample is directed from one end to the other end. By moving in one direction, it is possible to efficiently obtain the first transmittance of each of the detection element groups aligned in the first direction.

  According to the terahertz wave transmission measurement method of the seventh aspect, for each detection element, the γ value of γ correction for determining the actually measured first transmittance obtained by actual measurement to the first transmittance of the calibration sample is determined. The instrumental error between the plurality of detection elements can be properly calibrated by performing γ correction on the intensity detected by each detection element with the γ value.

It is a schematic side view showing composition of terahertz wave penetration measurement system 10 of a 1st embodiment. It is a schematic perspective view which shows the carrying amount measurement part 50 of 1st Embodiment. It is a schematic side view which shows the detector 54 of 1st Embodiment. It is a schematic front view which shows the carrying amount measurement part 50 of 1st Embodiment. It is a figure showing bus wiring concerning terahertz wave penetration measurement system 10 of a 1st embodiment. FIG. 6 is a schematic perspective view showing a configuration for performing a calibration process of the detector 54 using the calibration sample 70. FIG. 14 is a schematic side view showing another configuration for performing a calibration process of the detector 54 using the calibration sample 70. It is a figure which shows the transmittance | permeability distribution in the surface of the sample 70 for calibration. FIG. 5 is a diagram showing normalized measured transmittance for five detection elements 540 (elements 1 to 5). It is a figure which shows the transmittance | permeability after performing gamma correction | amendment of the measurement transmittance about five detection elements 540 shown in FIG. FIG. 18 is a diagram showing an intensity difference correction value list 621. It is a figure which shows the flow of the calibration process which calibrates the detection intensity difference | error between several detection elements 540. FIG. It is a figure which shows the measurement transmittance | permeability of several detection element 540. FIG. It is a figure which shows the transmittance | permeability obtained by (gamma) correction | amendment about the several detection element 540. FIG. It is a flow figure showing the flow of the amount measurement of loading of a 1st embodiment. It is a schematic side view which shows terahertz wave penetration measurement system 10a of a 2nd embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The constituent elements described in this embodiment are merely examples, and the scope of the present invention is not limited to them. In the drawings, for the sake of easy understanding, the dimensions and the numbers of the respective parts may be exaggerated or simplified as necessary.

<1. First embodiment>
<Configuration of Terahertz Wave Transmission Measurement System 10>
FIG. 1 is a schematic side view showing the configuration of the terahertz wave transmission measurement system 10 according to the first embodiment. FIG. 2 is a schematic perspective view showing the carried amount measuring unit 50 of the first embodiment. FIG. 3 is a schematic side view showing the detector 54 of the first embodiment. FIG. 4 is a schematic front view showing the carried amount measuring unit 50 of the first embodiment. FIG. 5 is a view showing the bus wiring according to the terahertz wave transmission measurement system 10 of the first embodiment.

  In each drawing, in order to facilitate understanding of the positional relationship of each component of the terahertz wave transmission measurement system 10, an XYZ orthogonal coordinate system is attached. In the following description, the direction in which the tip of the arrow points is the + (plus) direction, and the opposite direction is the − (minus) direction. However, this rectangular coordinate system does not limit the positional relationship of each component.

  The terahertz wave transmission measurement system 10 is, for example, an apparatus for manufacturing a polymer electrolyte fuel cell (PEFC), and more specifically, a platinum or the like on a surface of a substrate 90 which is a sheet-like electrolyte membrane. A metal catalyst is coated to produce an electrolyte membrane (CCM) with a catalyst layer.

  The terahertz wave transmission measurement system 10 may be configured to manufacture a membrane electrode assembly (MEA) in which a gas diffusion layer (GDL) is formed in a catalyst layer of CCM. The loading amount measurement unit 50 is suitable for measuring the loading amount of the catalyst layer formed in the CCM, but can also be applied to the loading amount measurement in the catalyst layer of MEA.

  The terahertz wave transmission measurement system 10 includes a transport unit 20 that transports the base material 90, a coating unit 30, a drying unit 40, a carried amount measurement unit 50, and a control unit 60. As described later, the supply roller 220, the winding roller 222, the encoder 226, the auxiliary transfer roller 240, the roller drive unit 28, the carried amount measuring unit 50, and the control unit 60 of the conveying unit 20 are an example of the carried amount measuring device. It is.

<Transport unit 20>
The conveyance unit 20 includes a supply roller 220, a winding roller 222, a conveyance auxiliary roller 240, and conveyance rollers 260, 262, and 264. The transport unit 20 also includes a roller drive unit 28 that rotates the winding roller 222. Each of these rollers is formed in a cylindrical shape extending in the Y-axis direction.

  The supply roller 220 and the winding roller 222 are formed so as to be able to wind and hold the sheet-like base material 90. Here, the supply roller 220 holds the substrate 90 to which the metal catalyst has not been applied in a wound state. The substrate 90 drawn from the supply roller 220 is wound around the winding roller 222 which is actively rotated by the roller drive unit 28. The transfer rollers 260, 262, and 264 and the transfer auxiliary roller 240 are disposed to support an intermediate portion of the base material 90 wound around the supply roller 220 and the take-up roller 222.

  The take-up roller 222 is provided with an encoder 226. The encoder 226 detects the movement distance of the substrate 90 by detecting the amount of rotation of the winding roller 222. That is, the encoder 226 is a movement distance detector that detects the relative movement distance of the substrate 90 in the X-axis direction (second direction) with respect to the oscillator 52 and the detector 54. The conveyance speed of the substrate 90 conveyed by the supply roller 220 and the take-up roller 222 may be arbitrarily set, but may be, for example, 25 mm / sec or less.

  The transport rollers 260, 262, and 264 are disposed between the supply roller 220 and the coating unit 30, and transport the substrate 90 while applying appropriate tension. In particular, the transport roller 264 is disposed at a position where the coating roller 30 contacts and supports the surface of the substrate 90 opposite to the surface on which the metal catalyst is applied.

  The conveyance auxiliary roller 240 is disposed on the downstream side of the drying unit 40, supports the base material 90, and is provided at a position where the base material 90 is pulled to remove wrinkles from the base material 90. A carried amount measuring unit 50 is provided on the downstream side of the conveyance auxiliary roller 240, and the terahertz wave output from the oscillator 52 is irradiated to the base material 90 passing through the area.

<Coating unit 30>
The coating unit 30 includes a slit nozzle 32 and a coating liquid supply unit 34. At the lower end portion of the slit nozzle 32, a discharge port formed in a slit shape extending along the width direction (Y-axis direction) of the substrate 90 is formed. The coating liquid supply unit 34 includes a tank 340 for storing the coating liquid of the metal catalyst, a pump 342 for supplying the coating liquid from the tank 340 to the slit nozzle 32, and start and stop of discharge of the coating liquid from the discharge port. A solenoid valve 344 for performing The operation of the solenoid valve 344 is controlled by the control unit 60.

  The lower end portion where the discharge port of the slit nozzle 32 is formed is disposed at a position close to the conveyance roller 264. By discharging the coating liquid from the discharge port of the slit nozzle 32, the coating liquid is applied to the base material 90 supported by the transport roller 264.

  In this example, the discharge port of the slit nozzle 32 is shorter than the length in the width direction of the substrate 90. For this reason, a coating liquid is apply | coated to the area | region inside only the predetermined distance from the both ends of the width direction among the base materials 90. As shown in FIG. As a result, as shown in FIG. 2, a catalyst layer 92 coated with a metal catalyst is formed on the inner side of the substrate 90 except for the both ends. And the edge part non-coating area | region 902 to which the metal catalyst is not coated in the both ends of the base material 90 is formed.

  Further, in the present example, the coating liquid is intermittently discharged from the slit nozzle 32. In detail, whenever it is detected by the encoder 226 that the substrate 90 has moved by a predetermined distance, the discharge of the coating liquid is alternately started or stopped. By this, as shown in FIG. 2, the coating area 900 is intermittently formed. That is, an intermediate non-coated region 904 to which the metal catalyst is not applied is formed between the catalyst layers 92 and 92 adjacent in the X-axis direction. The intermediate non-coated area 904 is an area extending in the Y-axis direction.

<Drying unit 40>
The drying unit 40 has a housing in which an entrance through which the base material 90 enters and an exit through which the base material 90 exits are formed at both ends. The drying unit 40 performs a drying process of the film of the coating liquid applied to one surface of the substrate 90 inside the housing. As an example, the drying unit 40 heats the substrate 90 by supplying hot air toward the substrate 90, thereby evaporating a solvent such as water contained in the coating liquid.

<Loading amount measuring unit 50>
The supported amount measurement unit 50 is provided on the downstream side of the drying unit 40, and measures the supported amount of the metal catalyst (catalyst supported amount) in the catalyst layer 92 formed on the substrate 90. The carried amount measuring unit 50 includes an oscillator 52 and a detector 54.

  The oscillator 52 outputs a fan-shaped terahertz wave that spreads in the Y-axis direction (the width direction of the base material 90) toward the base material 90 in the -Z direction. The terahertz wave is, for example, an electromagnetic wave of 0.03 THz to 10 THz. The terahertz wave output from the oscillator 52 is a continuous wave here, but may be a pulse wave. The terahertz wave fan-shapedly output from the oscillator 52 toward the base material 90 is irradiated to the base material 90.

  As shown in FIG. 3 and the like, the detector 54 includes a plurality of detection elements 540 and a housing 542. In FIG. 3, the case 542 is shown in cross section. The plurality of detection elements 540 are accommodated in the housing 542.

  A plurality of (for example, 256) detection elements 540 are arranged in a line in the Y-axis direction (width direction). Each of the detection elements 540 detects the intensity of the terahertz wave output from the oscillator 52. The detection element 540 may be composed of a known detector such as a Schottky barrier diode, a plasmonic detector (US Pat. Nos. 8,159,667 and 8,772,890), and a nonlinear optical crystal. The detection element 540 converts the intensity of an electromagnetic wave (terahertz wave) incident on the detection surface into an electrical signal. The electric signal output from each of the detection elements 540 is taken into the control unit 60. As the detection element 540, a photoconductive switch (photoconductive antenna) may be provided.

  As shown in FIG. 4, the plurality of detection elements 540 include a pair of detection elements 540a and 540a, a pair of detection elements 540b and 540b, and a plurality of detection elements 540c.

  The pair of detection elements 540a, 540a are disposed at both ends in the Y-axis direction. The pair of detection elements 540 a and 540 a are disposed outside the base material 90 in the Y-axis direction when viewed from the Z-axis direction. The pair of detection elements 540 a and 540 a are disposed at positions where the terahertz wave (terahertz wave passing outside the base material) passing the outer side in the Y-axis direction from the base material 90 can be detected.

  The pair of detection elements 540b and 540b are disposed at positions adjacent to the inside of the pair of detection elements 540a and 540a. The pair of detection elements 540 b and 540 b are disposed at positions that can detect terahertz waves (end transmitted terahertz waves) transmitted through the end non-coated regions 902 and 902 on both sides in the width direction of the base material 90. .

  The plurality of detection elements 540c are arranged between the detection elements 540b and 540b. Each of the detection elements 540c detects a terahertz wave (coating area transmission terahertz wave) transmitted through each portion of the coating area 900 (catalyst layer 92). For example, the plurality of detection elements 540c may be arranged at detectable intervals for each terahertz wave that transmits the substrate 90 at intervals of 0.1 mm to 10 mm in the Y-axis direction. This makes it possible to measure the supported amount with a resolution of 0.1 mm to 10 mm in the Y-axis direction. This resolution is equivalent to or better than the current punching weight measurement method (a measurement method of punching out a portion of the base material 90 on which the catalyst layer 92 is formed, measuring the weight of the punched portion, and specifying the supported amount) .

  As shown in FIG. 3, the housing 542 includes a housing portion 5420 and a cover portion 5422. Note that the housing portion 5420 is a portion that forms a rectangular parallelepiped housing space in which the plurality of detection elements 540 are housed. The cover portion 5422 constitutes a lid portion for closing the opening on the + Z side of the housing portion 5420. The cover portion 5422 is a member formed of a metal such as aluminum, and is also a portion covering the upper side (+ Z side) of the plurality of detection elements 540 accommodated in the accommodation portion 5420.

  A hole 543 extending in the Y-axis direction is formed in the central portion of the cover 5422 in the X-axis direction, and a window 544 made of resin is provided to close the hole 543. The window portion 544 is made of a material (specifically, a resin (particularly preferably a fluorine-based synthetic resin such as Teflon (registered trademark)) that transmits the terahertz wave output from the oscillator 52. The terahertz wave output from the oscillator 52 passes through the window portion 544 and is incident on each of the detection elements 540.

  The cover portion 5422 covers the + Z side of the plurality of detection elements 540, whereby the plurality of detection elements 540 can be protected. Furthermore, the plurality of detection elements 540 can be appropriately protected from the members disposed around the plurality of detection elements 540 by being accommodated in the housing 542 including the accommodation portion 5420 and the cover portion 5422.

<Control unit 60>
The control unit 60 controls the overall operation of the terahertz wave transmission measurement system 10. The configuration of the control unit 60 as hardware is the same as that of a general computer. That is, the control unit 60 includes a CPU that performs various arithmetic processing, a ROM that is a read only memory that stores basic programs, and a RAM that is a readable and writable memory that stores various information. The control unit 60 is connected to a storage unit 62 that stores a control application or various data.

  The control unit 60 controls the oscillation of the terahertz wave from the oscillator 52 on and off. That is, when the control unit 60 switches the oscillator 52 from off to on, the terahertz wave (continuous wave) is output in a fan shape from the oscillator 52 to the detector 54. In addition, when the control unit 60 switches the oscillator 52 from on to off, the output of the terahertz wave from the oscillator 52 is stopped.

  The white noise acquisition unit 602, the reference acquisition unit 603, the carried amount specification unit 61, and the notification unit 606 illustrated in FIG. 5 are functional modules realized as software by the CPU of the control unit 60 operating according to an application. . These functional modules may be configured by a hardware configuration such as a dedicated circuit.

  The white noise acquisition unit 602 acquires the white noise intensity (stationary noise) of the electric signal output from each of the detection elements 540 when the terahertz wave from the oscillator 52 is not incident. The white noise acquisition unit 602 acquires the electric field intensity detected by each of the detection elements 540 as the white noise intensity when the oscillator 52 is off. When the oscillator 52 is off, as viewed from the detection element 540, a sample that totally absorbs the terahertz wave (that is, a sample with a transmittance of 0%) is disposed between the oscillator 52 and the detection element 540. Thus, it can be said that the terahertz wave from the oscillator 52 is not transmitted. Therefore, in the following description, this white noise intensity is also referred to as "non-transmission intensity". The white noise acquisition unit 602 stores the white noise intensity detected by each of the detection elements 540 in the storage unit 62 as the non-transmission intensity A0.

  The reference acquisition unit 603 acquires the electric field intensity when each of the detection elements 540 detects the terahertz wave output from the oscillator 52. The acquisition of the reference intensity is performed in the absence of foreign matter such as the substrate 90 between the oscillator 52 and the detector 54. The reference intensity can also be said to be in a state in which a sample (that is, a sample having a transmittance of 100%) that totally transmits the terahertz wave is disposed between the oscillator 52 and the detection element 540. Therefore, in the following description, this reference intensity is also referred to as "total transmission intensity". The reference acquisition unit 603 stores the reference intensity detected by each of the detection elements 540 in the storage unit 62 as the total transmission intensity A100.

  A Y-axis direction moving unit may be provided to move the oscillator 52 and the detector 54 in the Y-axis direction. In this case, even when the base material 90 is supported by the pair of auxiliary rollers 582 and 582, the total transmission intensity A100 can be obtained by shifting the oscillator 52 and the detector 54 in the Y-axis direction.

<Sample transmission intensity acquisition unit for calibration 604>
The calibration sample transmission intensity acquisition unit 604 acquires, for each detection element 540, the transmission intensity when the terahertz wave transmitted through the calibration sample 70 is detected with the oscillator 52 turned on. As described later, the calibration sample transmission intensity acquisition unit 604 controls the calibration sample moving unit 74, which holds the calibration sample 70.

<Sample 70 for calibration>
FIG. 6 is a schematic perspective view showing a configuration for performing the calibration process of the detector 54 using the calibration sample 70. As shown in FIG. The calibration sample 70 is a reference sample prepared to calibrate the instrumental error between the plurality of detection elements 540. The calibration sample 70 is a silicon substrate formed in a rectangular plate shape having a uniform thickness. Here, a plurality of calibration samples 70 having different terahertz wave transmittances are prepared. For example, by changing the doping amount of the impurity to the silicon substrate, a calibration sample 70 having different transmittances is manufactured. The sheet resistance value is changed by changing the doping amount. Here, as a calibration sample 70, a silicon substrate having a sheet resistance value of 10 to 20 [Ω · cm], 700 to 1000 Ω · cm, of 1 to 2 [Ω · cm], 5 to 6 [Ω · cm]. Are prepared as the calibration samples 70a to 70d.

  The calibration sample 70 may be one in which a metal thin film is formed on a resin film having high film thickness uniformity. Also in this case, the calibration sample 70 with different transmittances can be obtained by making the thickness of the metal thin film different on the level of several nanometers to several tens of nanometres.

<Sample holder for calibration 72>
The calibration sample holder 72 holds the calibration sample 70 relative to the plurality of detection elements 540 between the oscillator 52 and the detector 54. Here, the calibration sample holding unit 72 is disposed on the top of the cover unit 5422 of the detector 54, and is a pair of sandwiching the calibration sample 70 from both sides (−X side and + X side) in the X axis direction. The holding members 721 and 721 are provided.

  The calibration sample moving unit 74 moves the calibration sample holding unit 72 in the Y-axis direction (first direction). The calibration sample moving unit 74 includes a drive unit 741 controlled by the calibration sample transmission intensity acquisition unit 604, and a pair of guide rails 742 and 742. The drive unit 741 can use an electric slider mechanism that rotationally drives a screw shaft on which a nut member on the slider side is screwed by driving a servo motor. The pair of guide rails 742 and 742 are provided on the top of the cover portion 5422 of the detector 54 and extend in the longitudinal direction of the detector 54, that is, the Y-axis direction. One of the pair of guide rails 742 and 742 is provided on the + X side of the hole 543, and the other is provided on the −X side of the hole 543.

  As shown in FIG. 6, the length of the calibration sample 70 in the Y-axis direction is the width dimension (between the detection elements 540a and 540a) between the detection elements 540 and 540 at both ends of the plurality of detection elements 540 arranged in a line The width is shorter than the distance in the Y-axis direction). For this reason, the calibration sample 70 can not cover all the detection elements 540 at one time. Therefore, the calibration sample moving unit 74 moves the calibration sample holding unit 72 holding the calibration sample 70 in the Y-axis direction in which the plurality of detection elements 540 are arranged. Thus, since the calibration sample 70 moves relative to the plurality of detection elements 540, the calibration sample 70 can be disposed on all the detection elements 540.

  The calibration sample moving unit 74 may move the calibration sample holding unit 72 at a pitch (= nd) that is an integral multiple (n times) of the arrangement pitch d of the detection elements 540. Thereby, for example, the transmission intensity of the terahertz wave can be measured for at least n detection elements 540 at a time in order from the detection element 540 (detection element 540a) at the end.

  The calibration sample moving unit 74 is not an essential component, and may be omitted. FIG. 7 is a schematic side view showing another configuration for calibrating the detector 54 using the calibration sample 70. As shown in FIG. Here, a pair of strip-shaped tape members 76 extending along the Y-axis direction is attached to the + X side and the −X side edge of the hole 543 in the cover portion 5422. The tape member 76 is formed of a nonconductive material. As described above, in the example illustrated in FIG. 7, the calibration sample 70 is held by the cover portion 5422 via the pair of tape members 76. As described above, by providing the pair of tape members 76, 76, it is possible to suppress direct contact of the calibration sample 70, which is a silicon substrate, with the cover portion 5422. Thus, the transmission characteristics of the calibration sample 70 are prevented from being changed. it can.

<Method of Determining Transmittance of Calibration Sample 70>
The transmittance of each of the calibration samples 70 a to 70 d may be determined using one detection element (hereinafter, referred to as “reference detection element”) 540 arbitrarily selected from the plurality of detection elements 540. Specifically, one of the calibration samples 70a to 70d is sequentially held in the calibration sample holder 72, and the intensity of the terahertz wave transmitted through each of the calibration samples 70a to 70d is detected by the reference detection element. Thereby, the transmission intensity of each of the calibration samples 70a to 70d is acquired. Then, the ratio (%) of the transmission intensity of each of the calibration samples 70a to 70d to the total transmission intensity A100 of the reference detection element is determined. As described above, the total transmission intensity A100 of the reference detection element can be regarded as the intensity when the terahertz wave transmitted through the sample having the transmittance of 100% is detected. Therefore, the transmittance of each of the calibration samples 70a to 70d is determined by determining the ratio of each transmission intensity to the total transmission intensity A100.

  In the following, the transmittance of the calibration sample 70a (1 to 2 Ω · cm) is 5%, the transmittance of the calibration sample 70b (5 to 6 Ω · cm) is 30%, and the calibration sample 70c (10 to 10 It is assumed that the transmittance of 20 Ω · cm) is determined to be 58%, and the transmittance of the calibration sample 70d is determined to be 70%. The transmission intensities when the terahertz waves transmitted through the calibration samples 70a to 70d are detected by the plurality of detection elements 540 are referred to as transmission intensities A5, A30, A58, and A70. As shown in FIG. 5, the calibration sample transmission intensity acquisition unit 604 stores the transmission intensities A5, A30, A58, and A70 acquired by the measurement in the storage unit 62.

  FIG. 8 is a view showing the transmittance distribution on the surface of the calibration sample 70. The calibration sample 70 shown in FIG. 8 is a calibration sample 70a having a transmittance of 5% doped with an impurity such that the sheet resistance value is 1 to 2 [Ω · cm]. As shown in FIG. 8, the calibration sample 70a has a vertical width of about 65 mm and a horizontal width of about 100 mm. When the transmittance distribution of the terahertz wave in the calibration sample 70a was examined, the error of the transmittance was 0.5% in the inner region excluding the periphery around the four sides. As described above, by doping the silicon substrate with an impurity, it is possible to obtain a calibration sample 70 having a uniform transmittance distribution.

  In addition, as shown in FIG. 8, in the longitudinal direction 10 mm of the calibration sample 70a, the transmittance is more uneven than the inner region. Therefore, it is considered that the regions at both ends are unsuitable for the measurement of the transmitted terahertz wave. In addition, near the end portions on both sides in the X-axis direction of the calibration sample 70, diffraction of the terahertz wave (wrapping of the terahertz wave to the back side) occurs. For this reason, when the vicinity of this end is used for measurement of the transmitted terahertz wave, there is a possibility that the transmitted intensity can not be measured correctly because the diffracted terahertz wave is incident on the detection element 540 on which the transmitted terahertz wave is incident. . For this reason, it is considered that it is unsuitable for the measurement of a transmitted terahertz wave about the both-ends part (area | region of width 10 mm) of X-axis direction. For these reasons, for each of the calibration samples 70, it is preferable to use the inner region excluding the regions at both ends in the X-axis direction (for example, the region of 10 mm in width) for the measurement of the transmitted terahertz wave.

<Supported Amount Identification Unit 61>
The supported amount specifying unit 61 specifies the supported amount of the metal catalyst coated on the substrate 90. The carried amount specifying unit 61 includes a position specifying unit 611 and a transmittance calculation unit 63.

  The position specifying unit 611 specifies a position (transmission position) on the base material 90 through which the terahertz wave incident on each of the plurality of detection elements 540 is transmitted. As shown in FIG. 6, the position specifying unit 611 specifies each of the transmission positions on the base material 90 through which the terahertz wave incident on each of the detection elements 540 c has passed. Each transmission position is specified from the positional relationship of each of the oscillator 52, the base material 90, the detection element 540 (the coordinate position in the XYZ rectangular coordinate system of each of the oscillator 52, base material 90, and detection element 540) and the output of the encoder 226 Based on the movement distance of the substrate 90 to be

  Here, as shown in FIG. 6, it is assumed that the centers of the oscillator 52 and the plurality of detection elements 540 coincide in the Y-axis direction. Here, paying attention to a specific detection element 540 located at the position L (j) from the center, the transmission position on the base material 90 through which the terahertz wave incident on the detection element 540 is transmitted is LP1 and the transmission position LP1 from the center Let L (i) be the distance to the end. Further, the distance from the oscillator 52 to the base material 90 is Db, and the distance from the base material 90 to the detection element 540 is Dd. Then, the distance L (i) is expressed by the following equation.

  L (i) = L (j) × Db ÷ (Db + Dd) (2)

  Based on this equation (2), the position in the width direction (Y-axis direction) of the base material 90 through which the terahertz wave incident on each of the detection elements 540 of the detector 54 is transmitted is specified.

  Further, based on the output of the encoder 226, the position specifying unit 611 specifies the position in the length direction (X-axis direction) of the base material 90 through which the terahertz wave incident on each of the detection elements 540 has passed. Specifically, the position specifying unit 611 sets the movement distance of the base material 90 (the movement distance relative to the detector 54) at the time of detection of the terahertz wave by the specific detection element 540 as the output of the encoder 226. Identify based on. As a result, the position in the length direction of the base material 90 through which the terahertz wave is transmitted is specified.

  As described above, the position specifying unit 611 specifies the position in the width direction and the position in the length direction where each terahertz wave in the base material 90 has transmitted, whereby the transmission position on the base material 90 for each terahertz wave is It is identified.

<Transmittance Calculation Unit 63>
The transmittance calculation unit 63 calculates the transmittance of the terahertz wave transmitted through the base material 90 from the electric field intensity detected by each of the detection elements 540. The transmittance calculation unit 63 calculates the transmittance by correcting the difference in intensity according to the difference between the plurality of detection elements 540 and the position of the plurality of detection elements 540 with respect to the oscillator 52 as described later. Do.

  The transmittance calculation unit 63 includes a normalization unit 631, a γ value determination unit 633, an intensity difference correction value acquisition unit 635, and a correction unit 637. The functions of these units will be described below.

<Normalization unit 631>
The normalization unit 631 specifies the minimum value A0 _min of the non-transmission intensities A0 of the detection elements 540 and the maximum value A100 _max of the total transmission intensities A100 of the detection elements 540. Then, the normalization unit 631 normalizes, for each detection element 540, the detected intensity such that the difference between the non-transmission intensity A0 and the total transmission intensity A100 matches the difference between the minimum value A0 _min and the maximum value A100 _max . Make linear corrections. Specifically, for the i-th detection element 540 counted from the -Y side, the non-transmission intensity A0 is A0 _i and the total transmission intensity A100 is A100 _i . In this case, the normalization unit 631 performs normalization by linear correction based on the following equation (3).

_{y = (A100 max -A0 min)} / (A100 i -A0 i) × (x- (A0 i)) ··· (3)

  In equation (3), x is the intensity detected by the ith detection element 540. Also, y is a normalized intensity obtained by linear correction of x. For example, in the calibration process, the normalization unit 631 normalizes the transmission intensities A5, A30, A58, and A70 (first transmission intensity and second transmission intensity) of each of the detection elements 540 according to the above equation (3).

Note that the minimum value A0 _min is not necessarily the minimum value among the non-transmission intensities A0 of all the detection elements 540. That is, the smallest one of the non-transmissive intensities A0 in some of the detection elements 540 arbitrarily selected may be A0 _min . Similarly, with regard to the maximum value A100 _max , the maximum among the total transmission intensities A100 of some of the detection elements 540 may be set as A100 _max .

In addition, instead of the normalization as described above, the normalization unit 631 is configured to calculate the difference between the non-transmission intensity A0 of each detection element 540 and the total transmission intensity A100 as the non-transmission intensity A0 of the arbitrary detection element 540 and the total transmission intensity. A linear correction may be made to match the difference of A100. In this case, in the above equation (3), “A100 _max ” may be replaced with the total transmission intensity A 100 of any detection element 540, and “A 0 _min ” may be replaced with the non-transmission strength A 0 of any detection element 540.

<Γ value determination unit 633>
The γ value determination unit 633 performs, for each of the detection elements 540, the actually measured transmittances determined from the transmission intensities A5, A30, A58, and A70 after normalization by the normalization unit 631 with each of the calibration samples 70a to 70d by γ correction. The γ values for approximating the transmittances 5%, 30%, 58% and 70% are acquired. The measured transmittance is a ratio of each transmission intensity A5, A30, A58, A70 to the total transmission intensity A100 after normalization.

  The γ value determination unit 633 performs fitting within a predetermined range of γ values. That is, for example, the γ value determination unit 633 sets the range of the γ value to 0.5 to 2, and changes the γ value in steps of 0.01. Then, the γ value determination unit 633 determines that the difference between the γ corrected value of the measured transmittance at each γ value and the transmittance of the calibration samples 70 a to 70 d is minimized by the least square method for each detection element 540. Determine the value. The γ value determination unit 633 stores, in the storage unit 62, γ value information 620 which is information indicating the γ value determined for each of the detection elements 540. The following equation (4) may be applied to the γ correction.

x ′ = a × (x / a) ^{1 / γ} . . . (4)

  In equation (4), x 'is a value after gamma correction, x is a value before gamma correction, and a is the maximum value of the output value. When the output value is expressed by 256 gradations, an output value of 256 gradations of 0 to 255 can be obtained, where a is “255”.

  FIG. 9 is a diagram showing normalized measured transmittances for five detection elements 540 (elements 1 to 5). Moreover, FIG. 10 is a figure which shows the transmittance | permeability after gamma-correcting the measurement transmittance about five detection elements 540 shown in FIG. In FIG. 9 and FIG. 10, the horizontal axis indicates the transmittance (the transmittance by the reference detection element) of the calibration samples 70a to 70d, and the vertical axis indicates the measured transmittance. Further, “element 1” to “element 5” correspond to each of five detection elements 540 among the plurality of detection elements 540.

  In the example shown in FIGS. 9 and 10, the γ value is “1.28” for element 1, “1.05” for element 2, “1.04” for element 3, and “1.18” for element 4. The element 5 is “1.18”. Comparing FIG. 9 and FIG. 10, for example, the measured transmittances of the elements 1 to 5 for the calibration sample 70c having a transmittance of 58% are values separated from the transmittance of 58% as shown in FIG. They are dispersed (45% to 53%), but after γ correction, they approach 58% overall as shown in FIG. Further, the measured transmittances of the elements 1 to 5 of the calibration sample 70d having a transmittance of 70% have less variation after the γ correction than before the γ correction. By thus determining the optimum γ value for each detection element 540 and performing the γ correction, it is possible to suppress the machine difference between the detection elements.

<Intensity difference correction value acquisition unit 635>
The intensity difference correction value acquisition unit 635 acquires an intensity difference correction value for each detection element 540. The intensity difference correction value is a correction value for correcting the detected intensity difference based on the difference in relative position of each detection element 540 with respect to the oscillator 52. In general, as the distance from the oscillator 52 to the detection element 540 increases, the intensity of the terahertz wave detected by the detection element 540 decreases. The intensity difference correction value acquisition unit 635 obtains, for each detection element 540, an intensity difference correction value for correcting the detection intensity difference between the detection elements 540 based on the difference in relative position.

  Specifically, for each detection element 540, the intensity difference correction value acquisition unit 635 performs γ correction on the total transmission intensity A 100 with the γ value determined by the γ value determination unit 633, and calculates the total transmission intensity A 100 after γ correction. Do. Then, for each detection element 540, the intensity difference correction value acquisition unit 635 obtains a value obtained by subtracting the total transmission intensity A100 after γ correction from a predetermined reference value as an intensity difference correction value.

  Here, the predetermined reference value is a value after γ correction of the total transmission intensity A100 of the reference detection element. However, it may be a value after γ correction of the total transmission intensity A100 in the detection element 540 other than the reference detection element. Also, the predetermined reference value may be an arbitrary value. The intensity difference correction value acquisition unit 635 stores, in the storage unit 62, an intensity difference correction value list 621 in which the acquired intensity difference correction values are listed (see FIG. 5).

  FIG. 11 is a diagram showing the intensity difference correction value list 621. In FIG. 11, detection elements 1 to 3 and detection element i correspond to a part of the plurality of detection elements 540. In the example shown in FIG. 11, the total transmission intensity A100 (reference total transmission intensity) after γ correction of the reference detection element is “6000”. On the other hand, the total transmission intensities A100 of the detection elements 1 to 3 and the detection element i after γ correction are “5600”, “5650”, “5700” and “6200”. Therefore, “+400”, “+350”, “+300” and “−200” can be obtained by subtracting the total transmission intensity A100 after each γ correction from the reference value (= 6000). These values are intensity difference correction values.

<Correction Unit 637>
The correction unit 637 corrects the electric field strength detected by each of the detection elements 540. Specifically, the correction unit 637 performs γ correction on the electric field intensity detected by each of the detection elements 540 with the γ value for each detection element 540 acquired by the γ value determination unit 633. By this γ correction, it is possible to correct the instrumental error between the plurality of detection elements 540. Further, the correction unit 637 performs intensity difference correction in which the intensity difference correction value is added to the electric field intensity after the γ correction. By this intensity difference correction, it is possible to correct a detection intensity error based on the difference in relative position with respect to the oscillator 52 among the plurality of detection elements 540.

  In addition, the correction unit 637 may perform a correction process of removing an error component generated due to an external cause from the electric field intensity detected by the detection element 540.

  For example, the correction unit 637 may correct the intensity of the coating region transmission terahertz wave detected by each of the detection elements 540c based on the intensity of the terahertz wave transmitted outside the base material detected by the pair of detection elements 540a. The out-of-substrate passing terahertz wave includes information on environmental changes (humidity change, temperature change, etc.) other than the substrate 90 or the catalyst layer 92 formed on the substrate 90. Therefore, by correcting the electric field intensity of the coated area transmitted terahertz wave based on the intensity change of the terahertz wave transmitted outside the base material, it is possible to remove an error component caused by an environmental factor. In particular, since terahertz waves have the property of being easily absorbed by water, removing the error component of environmental factors is extremely effective in specifying the catalyst loading amount with high accuracy.

  When correcting the coating area transmission terahertz wave based on the electric field strength of the terahertz wave transmitted outside the base material, for example, the electric field strength of the coating area transmission terahertz wave detected by the detection element 540c at a certain timing It is preferable to standardize by the electric field intensity of the terahertz wave transmitted from the outside of the base material detected by the detection element 540a. Alternatively, when the electric field intensity of the terahertz wave transmitted outside the base material increases or decreases from a predetermined reference value to a predetermined threshold value, the value corresponding to the increase / decrease value is appropriately used as the electric field intensity of the coated area transmission terahertz wave It may be subtracted or added.

  Further, the transmittance calculation unit 63 may correct the electric field intensity of the coating region transmission terahertz wave detected by each of the detection elements 540c based on the end portion transmission terahertz wave detected by the pair of detection elements 540b. The end transmitted terahertz wave is a terahertz wave transmitted through a portion of the base material 90 where the catalyst layer 92 is not formed. Therefore, by correcting the coating area transmission terahertz wave based on the intensity of the end portion transmission terahertz wave, an error component generated by transmitting through the base material 90 itself can be corrected.

  In the case of correction based on the electric field strength of the end transmitted terahertz wave, for example, when the electric field strength of the end transmitted terahertz wave increases or decreases from a predetermined reference value beyond a predetermined threshold value, These values may be appropriately subtracted or added to the electric field strength of the coated area transmission terahertz wave.

  Further, the transmittance calculation unit 63 corrects the electric field intensity of the coated area transmitted terahertz wave detected by each of the detection elements 540 c based on the intensity of the uncoated area transmitted terahertz wave transmitted through the intermediate non-coated area 904. May be Similarly to the end portion transmission terahertz wave, the non-coating region transmission terahertz wave is also a terahertz wave transmitted through a portion of the base material 90 where the catalyst layer 92 is not formed. By correcting the coating area transmission terahertz wave based on the intensity of the non-coating area transmission terahertz wave, an error component generated by the transmission of the base material 90 can be corrected.

  The end coated area transmission terahertz wave is detected by the pair of detection elements 540 b instead of the detection element 540 c that detects the coated area transmission terahertz waves. Since the positions of the pair of detection elements 540b and the plurality of detection elements 540c are different, the received light energy of the terahertz wave may be different, and there may be individual differences in detection sensitivity. On the other hand, the non-coating area transmission terahertz wave is detected by each of the detection elements 540c that detect the coating area transmission terahertz wave. Therefore, the correction process can be performed based on the electric field intensity of the non-coating region transmitted terahertz wave detected by each of the detection elements 540c. Therefore, regardless of the difference in the received light energy or the individual difference in the detection sensitivity, the error component included in the electric field intensity of the coated area transmission terahertz wave can be suitably corrected.

  As shown in FIG. 2, when the intermediate non-coated area 904 is formed intermittently at a predetermined interval, the electric field strength of the non-coated area transmitted terahertz wave is also adjacent to the interval (in the length direction of the base 90 The interval between the two middle non-coated areas 904, 904) is detected. Therefore, when performing the correction process, each coated area transmitted terahertz wave is generated based on the electric field strength of the uncoated area transmitted terahertz wave transmitted through the nearest intermediate non-coated area 904 detected immediately before. It is good to correct. Since the correction can be performed by the electric field intensity of the terahertz wave transmitted through the intermediate non-coated area 904 at the near position, the error component can be suitably removed.

  The transmittance calculation unit 63 obtains the transmittance based on the corrected electric field intensity corrected by the correction unit 637. The transmittance calculation unit 63 calculates the ratio of the electric field intensity corrected by the correction unit 637 to the total transmission intensity A 100 of each detection element 540 as the transmittance.

  The supported amount specifying unit 61 specifies the supported amount of the catalyst based on the transmittance calculated by the transmittance calculating unit 63 and the correspondence information 622 stored in the storage unit 62. Correspondence information 622 is information indicating the correlation between the transmittance of the terahertz wave transmitted through the catalyst layer and the catalyst loading amount. When the metal catalyst is irradiated with the terahertz wave, a part of the terahertz wave is absorbed or reflected according to the density of the metal catalyst, so that the transmittance of the terahertz wave has a high correlation with the amount of supported catalyst. For this reason, based on the transmittance of the terahertz wave and the correspondence information 622, the catalyst loading amount at each of the transmission positions of the coating region 900 can be accurately calculated.

  The correspondence information 622 may be acquired in advance by measuring the transmittance of the terahertz wave transmitted by the supported amount measurement unit 50 using a sample (reference sample) on which a catalyst layer having a known supported amount of catalyst is formed. At this time, correspondence information 622 may be obtained by using several reference samples having different catalyst loading amounts. The correspondence information 622 may be table data in which the permeability and the catalyst loading amount are associated in a one-to-one relationship, or represents a linear expression or a polynomial equation indicating the relationship between the permeability and the catalyst loading amount It may be a calibration curve data.

  The supported amount specifying unit 61 associates the specified supported amount of catalyst with the permeation position on the base material 90 specified by the position specifying unit 611, and stores it as the supported amount of catalyst data 624 in the storage unit 62.

  The measurement frequency (the number of times per unit time of taking in the electric field intensity from each of the detection elements 540) of the carried amount specifying unit 61 is not particularly limited, but may be, for example, 1 Hz or more. Assuming that the electric field intensity detected by each of the detection elements 540 is acquired once every 0.5 seconds, for example, the electric field intensity can be acquired every 5 mm if the transport speed of the substrate 90 is 10 mm / sec. By acquiring the electric field strength at measurement intervals of 0.1 mm to 10 mm, the catalyst loading amount can be measured with a resolution of 0.1 mm to 10 mm in the Y-axis direction. This resolution is equal to or higher than the current punching weight measurement method.

  The notification unit 606 outputs data on the catalyst loading amount on the base material 90 to the outside based on the catalyst loading amount data 624. For example, the notification unit 606 displays, on the display unit 64, a catalyst loading amount distribution image showing the distribution of the catalyst loading amount on the base material 90 based on the catalyst loading amount data 624. The catalyst loading distribution image is a two-dimensional image in which the size of the loading of the catalyst at each transmission position is represented by color or pattern, or a three-dimensional graph of the size of the loading of the catalyst at each transmission position. It may be an image.

  Further, the notification unit 606 notifies outside when there is a permeation position where the supported amount of catalyst exceeds a predetermined upper limit, and a permeation position where the supported amount of catalyst does not exceed the predetermined lower limit. The upper limit value and the lower limit value are values indicating the normal range of the catalyst loading amount. The upper limit value and the lower limit value may be input by the operator to the control unit 60 via the operation input unit 66 configured by an input device. The upper limit value and the lower limit value are stored in the storage unit 62 as upper limit value data 626 and lower limit value data 628, respectively.

  The notification unit 606 informs the outside that there is a permeation position where the supported amount of catalyst does not exceed the upper limit or a permeation position where the supported amount does not exceed the lower limit, so that the supported amount of catalyst is out of the normal value range. The operator can easily recognize. At this time, the operator can easily identify the position by displaying the permeation position on the catalyst loading amount distribution image by a predetermined method. The notification unit 606 may notify the presence or absence of an abnormality in the catalyst loading amount to the outside, for example, by lighting a lamp.

<Calibration process of detector 54>
Next, a calibration process for calibrating detection errors between the plurality of detection elements 540 of the detector 54 will be described. FIG. 12 is a diagram showing a flow of calibration processing for calibrating detection intensity errors among the plurality of detection elements 540. When the calibration process is started, first, the total transmission intensity A100 and the non-transmission intensity A0 are obtained for each of the plurality of detection elements 540 (step S10). The total transmission intensity A100 is obtained by detecting the terahertz wave oscillated from the oscillator 52 with each detection element 540 in a state where there is no foreign substance such as the base material 90 or the calibration sample 70 between the oscillator 52 and the detector 54. Be done. The non-transmission intensity A0 is obtained by the detection elements 540 detecting the electric field intensity while the oscillator 52 is off.

  Subsequently, one of the plurality of calibration samples 70a to 70d is held by the calibration sample holder 72, whereby the calibration sample 70 is installed on the detector 54 (step S11). ). The placement of the calibration sample 70 may be performed by a human or may be performed by a transport device (not shown).

  Subsequently, the calibration sample transmission intensity acquisition unit 604 controls the calibration sample moving unit 74 to move the calibration sample 70 to an appropriate position (step S12). The initial position of the calibration sample 70 is, for example, the end of the inner region (a region excluding 10 mm at both ends) of the terahertz wave incident on the detection element 540 a at the end among the plurality of detection elements 540. It is good to be in the position to pass through.

  Subsequently, when the calibration sample transmission intensity acquisition unit 604 causes the oscillator 52 to oscillate the terahertz wave, the intensity of the terahertz wave transmitted through the calibration sample 70 in a part of the detection element groups of the plurality of detection elements 540. The transmission intensity is measured (step S13). For example, when the calibration sample 70 is disposed at the initial position in step S12, in step S13, n terahertz waves transmitted through the inner region of the calibration sample 70 are n innermost detection elements from the end detection element 540a. Simultaneously to the detection element 540 of the Thereby, transmission intensity can be acquired by n detection element 540 units in one measurement. If the calibration sample 70 is, for example, a calibration sample 70a having a transmittance of 5%, the transmission intensity A5 of each detection element 540 is acquired in units of n detection elements 540 in step S12.

  Subsequently, the calibration sample transmission intensity acquisition unit 604 determines whether or not the measurement of the transmission intensity has been completed for all the detection elements 540 (step S14). If there is a detection element 540 whose transmission intensity with respect to the calibration sample 70 has not been measured (NO in step S14), the calibration sample transmission intensity acquisition unit 604 executes step S12 again. In the case where the transmission intensity is measured in units of n detection elements 540, in step S12, the calibration sample transmission intensity acquisition unit 604 sets the calibration sample 70 at a pitch n times the array pitch d of the detection elements 540 (= nd) It is good to move by Thereby, the transmitted intensity can be measured by the next n detection elements (n detection elements 540 counted from the (n + 1) th detection element 540).

  In step S14, when the calibration sample transmission intensity acquisition unit 604 determines that the transmission intensities of all the detection elements 540 have been acquired (YES in step S14), the calibration sample transmission intensity acquisition unit 604 is a unit for all the calibration samples. At step S15, it is determined whether the transmission intensity has been measured. When the calibration sample transmission intensity acquisition unit 604 determines that the determination is not made (NO in step S15), step S11 is executed. In step S11, among the plurality of calibration samples 70a to 70b, the calibration sample 70 whose transmission intensity has not been measured is selected and installed on the detector 54.

  In step S15, when it is determined that the measurement of the transmission intensity is completed for all of the calibration samples 70a to 70d (YES in step S15), the γ value determination unit 633 determines the γ value for each detection element 540. (Step S16). As described above, the γ value determination unit 633 calculates the measured transmittance from the normalized transmission intensities A5, A30, A58, and A70 for each detection element 540. Then, a γ value is determined for each detection element 540, which approximates the measured transmittance to the transmittances 5%, 30%, 58%, and 70% of the calibration samples 70a to 70d by γ correction.

  Subsequently, the intensity difference correction value acquisition unit 635 acquires an intensity difference correction value for each of the detection elements 540 (step S17). As described above, the intensity difference correction value acquisition unit 635 performs γ correction on the total transmission intensity A100 with the γ value determined in step S16. The intensity difference correction value acquisition unit 635 subtracts the total transmission intensity A100 of each detection element 540 from the reference value using the value of the total transmission intensity A100 of the reference detection element subjected to γ correction as a reference value. Calculate the intensity difference correction value for every 540.

  FIG. 13 is a diagram showing measured transmittances of the plurality of detection elements 540. As shown in FIG. FIG. 14 is a diagram showing the transmittances obtained by the γ correction for the plurality of detection elements 540. In FIG. 13 and FIG. 14, the horizontal axis indicates the number of the detection element 540, and the vertical axis indicates the calculated transmittance. Further, the transmittance shown in FIGS. 13 and 14 is based on the electric field intensity detected by each of the detection elements 540 when the calibration samples 70a to 70d are placed on the detection elements 540 having numbers 25 to 100. It has been sought.

  The measured transmittance shown in FIG. 13 is calculated by dividing each of the transmission intensities A5, A30, A58, and A70 measured using the calibration samples 70a to 70d by the total transmission intensity A100 for each detection element 540. It is a thing. In this case, it can be seen that the detection elements are largely dispersed.

  The transmittance shown in FIG. 14 is calculated by dividing each of the corrected (γ corrected and intensity difference corrected) transmission intensities A5, A30, A58, A70 by the corrected total transmission intensity A100 for each detection element 540. It is a thing. As shown in FIG. 14, by performing correction, the variation among the detection elements is largely suppressed, and the transmittance determined from the transmission intensities A5, A30, A58, and A70 is the calibration sample 70a determined by the reference detection element. It shows a value close to the transmittance of ~ 70d. Thus, by performing the calibration process, the detection error between the detection elements 540 can be properly calibrated.

<Measurement of supported amount>
Next, the flow of carried amount measurement performed in the terahertz wave transmission measurement system 10 will be described. In the measurement of the supported amount, the intensity of the terahertz wave transmitted through the base material 90 which is the measurement object is measured, and the supported amount of the metal catalyst in the catalyst layer 92 formed on the base material 90 is measured. That is, the measurement of the carried amount can be considered as one embodiment of the terahertz wave transmission measurement.

  FIG. 15 is a flow chart showing the flow of the carried amount measurement of the first embodiment. Each step shown in FIG. 15 is performed by controlling the operation of each element of the terahertz wave transmission measurement system 10 unless otherwise specified.

  First, the base material 90 is set in the transport unit 20 (step S20). Specifically, the end of the substrate 90 drawn from the supply roller 220 is stretched around each roller and attached to the winding roller 222.

  Then, control part 60 starts conveyance of substrate 90 (Step S21). Specifically, the control unit 60 controls the roller drive unit 28 to rotate the winding roller 222. As a result, the substrate 90 is fed from the supply roller 220, and the winding of the substrate 90 is performed by the winding roller 222.

  When transport of the base material 90 is started, the control unit 60 starts coating processing of the base material 90 (step S22). In detail, the control unit 60 controls the pump 342 to apply a coating liquid containing a metal catalyst such as platinum to the surface of the base material 90 from the slit nozzle 32 of the coating unit 30. A catalyst layer is formed in the part (coating area 900) in which the coating liquid of the metal catalyst in the base material 90 was coated by receiving a drying process in the drying part 40. Here, as shown in FIG. 2, since the catalyst layer is intermittently performed, in the base material 90, the coated regions 900 corresponding to the catalyst layer and the intermediate non-coated regions 904 alternate in the longitudinal direction. Is formed.

  After the coating process is started, the control unit 60 causes the supported amount measuring unit 50 to start irradiation of the terahertz wave from the oscillator 52 to the substrate 90 (step S23). Specifically, the control unit 60 turns the oscillator 52 on, and the terahertz wave is output from the oscillator 52 so as to fan out.

  When the irradiation of the terahertz wave is started, the control unit 60 starts the measurement of the electric field intensity in the plurality of detection elements 540 of the detector 54 (step S24). In addition, the position specifying unit 611 specifies the upper surface of the base material 90 through which the terahertz wave incident on the plurality of detection elements 540 is transmitted (step S25). That is, the position specifying unit 611 specifies the position on the base material 90 where the terahertz wave is incident (the position of the side on the base material 90 where the YZ plane passing through the oscillator 52 intersects). This position is a measurement position at which the catalyst loading amount is measured when the terahertz wave is incident. The control unit 60 stores the electric field intensity obtained by the measurement in step S24 in the storage unit 62 at an appropriate timing.

  Identification of the incident position on the substrate 90 can be realized by monitoring a pulse signal or the like sent from the encoder 226. The encoder 226 may be connected to a roller other than the winding roller 222 and may detect the amount of rotation of the connected roller. Also, the amount of movement of the substrate 90 may be detected directly. For example, it may be either a contact or non-contact sensor. An optical sensor (image sensor) may be employed as the noncontact sensor. For example, the control unit 60 may identify the coated area 900 and the intermediate non-coated area 904 by image processing using an optical sensor, and measure the amount of movement of the substrate 90 based on this.

  Subsequently, the control unit 60 determines whether or not the measurement of the terahertz wave is completed (step S26). For example, the control unit 60 may determine based on whether the measurement position specified in step S25 is inside or outside the measurement target range preset in the base material 90. When the control unit 60 determines that the measurement is to be continued (NO in step S26), the measurement of the electric field strength in step S24 and the specification of the measurement position in step S25 are repeated. When the measurement frequency of the electric field intensity in step S24 is 1 Hz, the frequency of specifying the measurement position in step S25 is also 1 Hz.

  On the other hand, when it is determined that the control unit 60 completes the measurement (YES in step S26), the control unit 60 stops the transport and coating process of the base material 90 (step S27). Specifically, the control unit 60 stops the take-up roller 222 to stop the feeding of the base material 90 from the supply roller 220 and the take-up by the take-up roller 222 (step S27). Further, the control unit 60 stops the discharge of the coating liquid from the slit nozzle 32 by stopping the pump 342.

  Subsequently, the control unit 60 stops the irradiation of the terahertz wave (step S28). Specifically, the control unit 60 switches the oscillator 52 to the off state to stop the oscillation of the terahertz wave.

  Subsequently, normalization, γ correction, and intensity difference correction are performed on the electric field intensity obtained in step S24 for each detection element 540 (step S29). In detail, the normalization unit 631 performs normalization by linear correction on the electric field strength obtained in step S24. Then, the correction unit 637 performs γ correction on the normalized electric field strength. The γ value used in this γ correction is a value determined for each detection element 540 by the γ value determination unit 633 in step S16 shown in FIG. Further, the correction unit 637 corrects the γ-corrected electric field strength with the strength difference correction value. This intensity difference correction value (see FIG. 11) is a value acquired by the intensity difference correction value acquisition unit 635 in step S17 shown in FIG.

  Thus, by applying the γ correction to the detected electric field strength for each detection element 540, the instrumental error between the detection elements 540 can be corrected. In addition, by correcting the γ-corrected electric field strength with the strength difference correction value for each detection element 540, it is possible to correct the detection strength difference based on the difference in relative position with respect to the oscillator 52.

  Subsequently, the transmittance calculation unit 63 calculates the transmittance of each measurement position of the substrate 90 (step S30). Specifically, the transmittance is obtained by dividing the corrected electric field strength obtained in step S29 by the corrected total transmission strength A100.

  Subsequently, the loaded amount specifying unit 61 refers to the correspondence information 622 and specifies the loaded amount of catalyst from the transmittance at each measurement position calculated in step S30. Thereby, distribution information of the catalyst loading amount is obtained (step S31).

<2. Second embodiment>
Next, a second embodiment will be described. In the following description, elements having the same functions as the elements already described may be denoted by the same reference numerals or reference numerals with alphabetical characters added, and detailed description may be omitted.

  The terahertz wave transmission measurement system 10 according to the first embodiment includes a coating unit 30 and a drying unit 40. However, the provision of the coating unit 30 and the drying unit 40 is not essential.

  FIG. 16 is a schematic side view showing the terahertz wave transmission measurement system 10a of the second embodiment. In the terahertz wave transmission measurement system 10, the base material 90 having the catalyst layer 92 formed on the surface is wound around the supply roller 220, and the base material 90 delivered from the supply roller 220 is the winding roller 222 It will be rolled up. Then, the supported amount measuring unit 50 applies the terahertz wave from the oscillator 52 to the intermediate portion of the base material 90 transported by the roll-to-roll, and detects the terahertz wave transmitted through the base material 90 with the detector 54. The present invention is effective even in such a configuration.

<3. Modified example>
As mentioned above, although embodiment was described, this invention is not limited to the above things, A various deformation | transformation is possible.

  In the above-described embodiment, in the calibration process of the detector 54, four types of calibration samples 70a to 70d (samples with transmittances larger than 0% and smaller than 100%) having different transmittances are used. However, the calibration process may be performed using only one calibration sample 70. An appropriate γ value can be obtained by using a plurality of calibration samples 70. At this time, it is desirable that the plurality of calibration samples 70 include a sample with a transmittance of more than 0% and 50% or less and a sample with a transmittance of 50% or more and less than 100%. Thereby, when the γ value determination unit 633 determines the γ value, fitting can be performed in the region of 50% or less and the region of 50% or more, so that a more optimal γ value can be obtained.

  In addition, it is not essential that the detection elements 540 are arranged in a line in the Y-axis direction. The plurality of detection elements 540 may be arranged in the Y-axis direction while being shifted in the X-axis direction. For example, the plurality of detection elements 540 may be arranged in two rows along the Y-axis direction, and the detection elements 540 in one row may be shifted in the Y-axis direction with respect to the detection elements 540 in the other row. By arranging in this manner, more detection elements 540 can be arranged in the Y-axis direction, so that the resolution in the Y-axis direction can be improved. When the number of detection elements 540 mounted on the detectors 54 is small, a plurality of detectors 54 may be arranged in the Y-axis direction. At this time, the plurality of detectors 54 may be arranged in the Y axis direction while being shifted in the X axis direction.

  In the above embodiment, the terahertz wave transmission measurement system 10 has described the example in which the substrate 90 on which the catalyst layer 92 of the metal catalyst is formed is the measurement object. However, the measurement target of the terahertz wave transmission measurement system 10 is not limited to such a base material 90.

  Although the present invention has been described in detail, the above description is an exemplification in all aspects, and the present invention is not limited thereto. It is understood that countless variations not illustrated are conceivable without departing from the scope of the present invention. The configurations described in the above-described embodiments and the modifications can be appropriately combined or omitted as long as no contradiction arises.

10, 10a Terahertz wave transmission measurement system 20 transport unit 220 supply roller 222 take-up roller 226 encoder 28 roller drive unit 50 supported amount measurement unit 52 oscillator 54 detector 540 detection element 542 housing 5420 accommodation unit 5422 cover unit 60 control Part 602 White noise acquisition part 603 Reference acquisition part 604 Sample transmission intensity acquisition part for calibration 606 notification part 61 Load amount identification part 611 Position identification part 62 Storage part 620 γ value information 621 Intensity difference correction value list 63 Transmittance calculation part 631 Normal Converting unit 633 γ value determination unit 635 Intensity difference correction value acquisition unit 637 Correction unit 70, 70a to 70d Calibration sample 72 Calibration sample holding unit 721 Clamping member 74 Calibration sample moving unit 740 Drive unit 741 Drive unit 742 Guide rail 90 Substrate 92 Catalyst layer A No transmission intensity A5, A30, A58, A70 transmission intensity A100 all transmission intensity

Claims (7)

A terahertz wave transmission measurement system for measuring the intensity of terahertz waves transmitted through an object to be measured, comprising:
An oscillator that oscillates terahertz waves;
A detector having a plurality of detection elements for detecting terahertz waves;
A control unit that performs on / off control of oscillation of the terahertz wave in the oscillator;
A first calibration sample having a first transmittance characteristic with respect to the terahertz wave;
A sample holder for holding the first calibration sample so as to be movable relative to the plurality of detection elements between the oscillator and the detector;
For each of the detection elements,
(A) non-transmissive intensity which is intensity detected by each of the detection elements in a state where the terahertz wave is not oscillated from the oscillator;
(B) total transmission intensity which is intensity detected by each of the detection elements in a state where the terahertz wave is oscillated from the oscillator;
(C) a first transmission intensity which is an intensity detected by each of the detection elements when the terahertz wave passes through the first calibration sample in a state where the terahertz wave is oscillated from the oscillator;
An intensity storage unit for storing
The non-transmissive intensity of each of the detection elements, the total transmissive intensity, and the second transmission intensity of each of the detection elements based on the minimum value of the non-transmission intensity of each of the detection elements and the maximum value of the total transmission intensity of each of the detection elements 1 A normalization unit that normalizes the transmitted intensity,
A γ value determination unit that determines a γ value that approximates the measured first transmittance calculated from the normalized first transmission intensity to the first transmittance by γ correction for each of the detection elements;
A correction unit that corrects the intensity detected by each of the detection elements based on the γ value;
And a terahertz wave transmission measurement system. The terahertz wave transmission measurement system according to claim 1,
A second calibration sample having a second transmittance characteristic different from the first transmittance with respect to the terahertz wave;
And further
The sample holder can hold the second calibration sample.
The intensity storage unit is configured for each of the detection elements.
(D) a second transmission intensity detected when the terahertz wave passes through the second calibration sample;
Remember
The normalization unit further normalizes the second transmission intensity,
The γ value determination unit obtains, for each of the detection elements, a γ value that approximates the normalized first transmittance and the second transmittance to the first transmittance and the second transmittance by γ correction. The terahertz wave transmission measurement system. The terahertz wave transmission measurement system according to claim 2,
The terahertz wave transmission measurement system, wherein the first and second calibration samples are silicon substrates having different sheet resistance values. Terahertz wave transmission measurement system,
One of the plurality of detection elements is a reference detection element,
The terahertz wave transmission measurement system, wherein the first transmittance of the first sample is determined based on the intensity when the transmission terahertz wave transmitted through the first sample is measured by the reference detection element. The terahertz wave transmission measurement system according to any one of claims 1 to 4,
An intensity difference correction value for acquiring an intensity difference correction value for each detection element by subtracting the corrected total transmission intensity obtained by performing γ correction on the total transmission intensity from the predetermined reference value for each detection element Acquisition department,
And further
The terahertz wave transmission measurement system, wherein the correction unit performs correction in which the intensity difference correction value is added to the intensity of the terahertz wave detected by each of the plurality of detection elements. The terahertz wave transmission measurement system according to any one of claims 1 to 5,
The plurality of detection elements include a detection element group arranged at a predetermined pitch in a first direction,
The first calibration sample has a width dimension shorter than the width of both ends of the detection element group,
The terahertz wave transmission measurement system, wherein the calibration sample holder movably holds the first calibration sample along the first direction. A terahertz wave transmission measurement method in which a terahertz wave oscillated from an oscillator and transmitted through an object to be measured is detected by a plurality of detection elements.
(A) Each of the plurality of detection elements
(A) non-transmissive intensity which is intensity detected by each of the detection elements in a state where the terahertz wave is not oscillated from the oscillator;
(B) total transmission intensity which is intensity detected by each of the detection elements in a state where the terahertz wave is oscillated from the oscillator, and (C) the terahertz wave in a state where the terahertz wave is oscillated from the oscillator A first transmission intensity which is an intensity detected by each of the detection elements when transmitting through the first calibration sample;
And storing the
(B) The non-transmissive intensity of each of the detection elements, the total transmissive intensity, based on the minimum value of the non-transmissive intensities of each of the detection elements and the maximum value of the total transmissive intensities of each of the detection elements And normalizing the first transmission intensity,
(C) For each detection element, determine a γ value that approximates the measured first transmittance determined from the first transmittance normalized in the step (b) to the first transmittance by γ correction. Process,
(D) correcting the intensity detected by each of the detection elements based on the γ value of each of the detection elements;
Terahertz wave transmission measurement method.