JP2016121921A - Inspection method and inspection device for detecting attachment attached to object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection method capable of calculating the position and amount of attachments attached to an object with high accuracy.SOLUTION: An antenna element 20 including a conductive pattern 22 provided with intervals opened is attached to an object. An inspection method includes an irradiation step for irradiating electromagnetic waves within the frequency range of 0.1THz to 3THz to the object, a measurement step for measuring the frequency characteristics of reflection waves being electromagnetic waves reflected by the antenna element attached to the object, and an analysis step for analyzing measurement information acquired by the measurement step. In the analysis step, attachments are detected on the basis of the fact that peak frequencies of a peak waveform appearing in frequency characteristics of the reflection waves on the basis of the conductivity of conductive materials constituting the conductive pattern of the antenna element and the intervals provided in the conductive pattern are changed in accordance with the existence of attachments overlapping the antenna element.SELECTED DRAWING: Figure 3A

Description

  The present invention relates to an inspection method and an inspection apparatus that detect an adhering matter attached to an object by irradiating the object with electromagnetic waves.

  Conventionally, a technique for detecting an image or a substance existing in an invisible place using electromagnetic waves has been proposed. For example, in Patent Document 1, it is proposed to use a terahertz wave. Terahertz waves have the property that they can penetrate many packaging materials such as paper and resin. Therefore, if the terahertz wave is used, information on the container accommodated in the container made of paper or resin can be obtained in a non-contact and non-opening manner.

  As another technique using the terahertz wave, for example, in Patent Document 2, an object to be measured is attached to an element including a metal mesh, and the terahertz wave is irradiated toward the object to be measured. It has been proposed to analyze the characteristics of the object to be measured by analyzing the above.

JP 2013-178212 A International Publication No. 2013/073242 Pamphlet

  In the inspection technique, it may be required to quantitatively analyze the object to be measured that exists in an invisible place. However, it is possible to obtain information on the type of the container when inspecting the container accommodated in the container based on the waveform information and spectrum information of the terahertz wave as in Patent Document 1 described above. However, it is considered difficult to quantitatively analyze the contents.

  In Patent Document 2 described above, the characteristics of a substance attached to the metal mesh of the element are analyzed by utilizing surface plasmon resonance of terahertz waves. In this case, the metal mesh needs to have a periodic structure obtained by periodically arranging the gaps in one direction. This complicates the device manufacturing process and increases the manufacturing cost. In addition, since the difference in measurement results according to the difference in the location of the substance is unlikely to occur, it is difficult to calculate the distribution of the location of the substance quantitatively and accurately with the technique of Patent Document 2. It is done.

  The present invention has been made in consideration of such points, and an object thereof is to provide an inspection method and an inspection apparatus capable of accurately calculating the position and amount of a substance attached to an object.

  The present invention is an inspection method for irradiating an object with electromagnetic waves and detecting an adhering matter adhering to the object, wherein an antenna element including a conductive pattern provided with a gap is attached to the object. The inspection method includes an irradiation step of irradiating the object with the electromagnetic wave, a measurement step of measuring a frequency characteristic of a reflected wave that is the electromagnetic wave reflected by the antenna element attached to the object, and the measurement An analysis step of analyzing the measurement information obtained by the step, and the electromagnetic wave applied to the object has a component from a first frequency to a second frequency on a higher frequency side than the first frequency. Each of the first frequency and the second frequency is within a range of 0.1 THz to 3 THz. In the analysis step, the antenna is The peak frequency of the peak waveform that appears in the frequency characteristics of the reflected wave based on the conductivity of the conductive material constituting the conductive pattern of the element and the gap provided in the conductive pattern overlaps the antenna element. It is an inspection method in which the deposit is detected based on the fact that the deposit varies depending on the presence of the deposit.

  In the inspection method according to the present invention, a peak of a peak waveform appearing in a frequency characteristic of the electromagnetic wave reflected by the antenna element when the attached matter overlaps a certain part or all of the conductive pattern of the antenna element. The frequency may be acquired in advance as a reference peak frequency. In this case, in the analysis step, the peak frequency of the peak waveform appearing in the frequency characteristics of the reflected wave measured in the measurement step is compared with the peak frequency for reference by comparing the peak frequency for reference. The ratio of the part which overlaps with the said deposit | attachment among electroconductive patterns may be calculated.

  In the inspection method according to the present invention, a plurality of the antenna elements may be attached to the object. In this case, each antenna element is arranged such that the peak frequency of the electromagnetic wave reflected by one of the two adjacent antenna elements is not affected by the other antenna element. May be.

  In the inspection method according to the present invention, the conductive pattern of the antenna element includes a pair of first elements disposed with the gap therebetween, and a pair of second elements connected to the pair of first elements, respectively. The pair of second elements extends in a direction different from the direction in which the pair of first elements extends, and the distance between the pair of second elements is greater than the gap. It may be.

  In the inspection method according to the present invention, the detected deposit may be water.

  In the inspection method according to the present invention, the object may be a container formed of paper or opaque resin, and the antenna element may be attached to a place other than the outer surface of the container.

  In the inspection method according to the present invention, the object may be an opaque wall, and the antenna element may be attached to a place other than the outer surface of the wall.

  The present invention is an inspection apparatus that detects an object attached to an object by irradiating the object with electromagnetic waves, and the object is provided with an antenna element including a conductive pattern provided with a gap. The inspection apparatus includes an irradiation unit that irradiates the object with the electromagnetic wave, a measurement unit that measures a frequency characteristic of a reflected wave that is the electromagnetic wave reflected by the antenna element attached to the object, and the measurement An analysis unit that analyzes the measurement information obtained by the unit, and the electromagnetic wave applied to the object has a component from a first frequency to a second frequency on a higher frequency side than the first frequency. Each of the first frequency and the second frequency is within a range of 0.1 THz to 3 THz, and the analysis unit includes a front of the antenna element. The peak frequency of the peak waveform appearing in the frequency characteristics of the reflected wave based on the conductivity of the conductive material constituting the conductive pattern and the gap provided in the conductive pattern is the amount of the deposit that overlaps the antenna element. It is an inspection apparatus in which the deposit is detected based on changing according to the presence.

  In the inspection apparatus according to the present invention, a peak of a peak waveform appearing in a frequency characteristic of the electromagnetic wave reflected by the antenna element when the attached matter overlaps a certain part or all of the conductive pattern of the antenna element. The frequency may be acquired in advance as a reference peak frequency. In this case, the analysis unit compares the peak frequency of the peak waveform appearing in the frequency characteristics of the reflected wave measured by the measurement unit with the peak frequency for reference, thereby comparing the peak frequency of the antenna element. The ratio of the part which overlaps with the said deposit | attachment among electroconductive patterns may be calculated.

  In the inspection apparatus according to the present invention, a plurality of the antenna elements may be attached to the object. In this case, each antenna element is arranged such that the peak frequency of the electromagnetic wave reflected by one of the two adjacent antenna elements is not affected by the other antenna element. May be.

  In the inspection apparatus according to the present invention, the conductive pattern of the antenna element includes a pair of first elements arranged with the gap therebetween, and a pair of second elements connected to the pair of first elements, respectively. The pair of second elements extends in a direction different from the direction in which the pair of first elements extends, and the distance between the pair of second elements is greater than the gap. It may be.

  In the inspection apparatus according to the present invention, the detected deposit may be water.

  In the inspection apparatus according to the present invention, the object may be a container made of paper or opaque resin, and the antenna element may be attached to a place other than the outer surface of the container.

  In the inspection apparatus according to the present invention, the object may be an opaque wall, and the antenna element may be attached to a place other than the outer surface of the wall.

  According to the present invention, it is possible to accurately calculate the position and amount of a deposit attached to an object.

It is a top view which shows the structure of the container which concerns on embodiment of this invention. It is sectional drawing which shows the structure of the AA cross section of the container of FIG. It is a top view which shows the antenna element attached to the inner surface of a container. It is a figure which shows the frequency characteristic of the reflected wave obtained when electromagnetic waves are irradiated to the antenna element shown to FIG. 3A. It is a top view which shows a mode that the deposit | attachment adhered to the antenna element. It is a figure which shows the frequency characteristic of the reflected wave obtained when electromagnetic waves are irradiated to the antenna element shown to FIG. 4A. The figure which shows the relationship between the ratio of the part which has overlapped with the deposit | attachment among antenna elements, and a peak frequency. It is a figure showing the schematic structure of the inspection device concerning the embodiment of the present invention. It is a figure which shows a mode that electromagnetic waves are irradiated to the antenna element attached to the inner surface of a container. It is a figure which shows the frequency characteristic of the measured reflected wave. It is a top view which shows the modification of the electroconductive pattern of an antenna element. It is a top view which shows the modification of the electroconductive pattern of an antenna element. It is a top view which shows the modification of the electroconductive pattern of an antenna element. It is sectional drawing which shows one modification of an antenna element. It is sectional drawing which shows the antenna element attached to the wall body. It is a top view which shows the example in which a some antenna element is provided in an object. It is a top view which expands and shows one of the several antenna element shown in FIG. It is a top view which shows the other example in which a some antenna element is provided in an object. It is a top view which expands and shows one of the several antenna element shown in FIG. It is a figure which shows the frequency characteristic of the reflected wave measured in Example 1. FIG. It is a figure which shows the frequency characteristic of the reflected wave measured in Example 2. FIG. It is a figure which shows the frequency characteristic of the reflected wave measured in the comparative example 1. FIG.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings attached to the present specification, for the sake of illustration and ease of understanding, the scale, the vertical / horizontal dimension ratio, and the like are appropriately changed and exaggerated from those of the actual product.

  In the present embodiment, an example will be described in which the object to which the antenna element 20 is attached is a container 10 that can store a predetermined container. Moreover, the water adhering to the container 10 by dew condensation etc. is assumed as a substance adhering to an object. In the following description, a substance that adheres to an object is also referred to as an attached substance. FIG. 1 is a plan view showing the configuration of the container 10. FIG. 2 is a cross-sectional view showing the configuration of the AA cross section of the container 10 of FIG.

The container container 10 includes an opaque layer made of paper or opaque resin. For this reason, visible light and infrared rays are reflected or absorbed by the container 10. That is, visible light and infrared rays cannot pass through the container 10. Therefore, the state inside the container 10 cannot be confirmed from the outside of the container 10. “Opaque” means that when an object such as the container 10 or the wall 40 described later is irradiated with infrared or visible light, the infrared or visible light does not pass through the object at all, and the infrared or visible light does not pass through the object. Even if it is transmitted, it means that the amount of transmitted light is so small that the transmitted infrared or visible light cannot be detected by the sensor.

  As the paper constituting the container 10, for example, cardboard is used. The container 10 may be a so-called cardboard envelope. In this case, the container 10 has an envelope shape, and includes an envelope part 11 and a flap part (margin) 12 provided at an opening of the envelope part 11. The flap portion 12 is folded back by 180 ° and adhered to the adhesion region 11a of the envelope portion 11, whereby the container 10 which is a cardboard envelope is sealed. FIG. 1 shows the container 10 before the flap 12 is folded back.

  As illustrated in FIG. 2, the container 10 includes a first layer 13 that is a cardboard, and a second layer 14 and a third layer 15 that are stacked on the first layer 13. Of the two surfaces facing outward of the first layer 13 formed in an envelope shape, the second layer 14 is laminated and bonded to one surface, and the third layer 15 is laminated to the other surface. It is glued.

  The antenna element 20 is provided at a location shielded from the outside by an opaque layer made of paper or opaque resin. For example, the antenna element 20 is provided in a place other than the outer surface 10 x of the container 10 in the container 10. In the example shown in FIG. 2, the antenna element 20 is attached to the inner surface 10 y of the housing body 10, specifically, the surface of the first layer 13 facing the inside of the housing body 10. The outer surface 10x is a surface that faces the outer side of the container 10 when the container 10 is sealed, that is, a surface that can be visually recognized by the naked eye. Further, the inner surface 10y is a surface in contact with the space inside the container 10.

Antenna element will be described below the antenna element 20. The antenna element 20 is attached to an object in order to confirm the environment in an invisible place among objects such as the container 10 in a nondestructive manner. As shown in FIG. 2, the antenna element 20 includes a base material 21 attached to the inner surface 10 y of the container 10 and a conductive pattern 22 provided on the base material 21. The base material 21 includes a first surface 21a and a second surface 21b located on the opposite side of the first surface 21a, and the conductive pattern 22 described above is provided on the first surface 21a side of the base material 21. It has been. In addition, the antenna element 20 is attached to the inner surface 10y so that the second surface 21b side of the base material 21 faces the inner surface 10y of the container 10.

  The conductive pattern 22 is made of a conductive material that can conduct electricity with a predetermined conductivity. As shown in FIG. 2, the conductive pattern 22 is provided with a predetermined gap 25 therebetween. In this case, when the antenna element 20 is irradiated with electromagnetic waves, the frequency characteristics of the electromagnetic waves reflected by the antenna element 20 are based on the conductivity of the conductive material constituting the conductive pattern 22 and the size of the gap 25. The determined peak waveform appears. In the present embodiment, based on the peak waveform, it is possible to inspect the internal state of the container 10, specifically, the deposit 30 attached to the antenna element 20 inside the container 10. The antenna element 20 is configured.

  As long as the electromagnetic wave can be reflected, the conductive material constituting the conductive pattern 22 is not particularly limited. For example, conductive materials such as various metal materials and carbon, composite materials in which two or more conductive materials are combined, and the like can be used as the conductive material constituting the conductive pattern 22. The thickness of the conductive pattern 22 is set within a range of 50 nm to 30 μm, for example.

  As long as the electromagnetic wave can be transmitted, the material constituting the base material 21 is not particularly limited, and a non-conductive material such as PET can be appropriately used. The transmittance of the base material 21 with respect to electromagnetic waves is at least 50% or more, preferably 80% or more.

  Next, the structure of the antenna element 20 and the frequency characteristics of the electromagnetic wave reflected by the antenna element 20 will be described in more detail with reference to FIGS. 3A to 4B. In the following description, the electromagnetic wave reflected by the antenna element 20 is also referred to as a reflected wave.

  FIG. 3A is a plan view showing the antenna element 20 attached to the inner surface 10 y of the container 10. FIG. 3B is a diagram illustrating frequency characteristics of reflected waves obtained when the antenna element illustrated in FIG. 3A is irradiated with electromagnetic waves. In the present embodiment, as will be described later, the electromagnetic wave applied to the container 10 is an electromagnetic wave including components from the first frequency f1 to the second frequency f2 on the higher frequency side than the first frequency f1. The first frequency f1 and the second frequency f2 are both electromagnetic waves belonging to the range of 0.1 THz to 3 THz. That is, the antenna element 20 is irradiated with an electromagnetic wave having a frequency range of 0.1 THz to 3 THz. Electromagnetic waves in the frequency range of 0.1 THz to 3 THz are also called so-called terahertz waves.

  The conductive pattern 22 is configured such that the peak waveform of the frequency characteristic of the reflected wave appears in a frequency range of 0.1 THz to 3 THz. In FIG. 3B, the peak waveform that appears in the frequency characteristics of the reflected wave obtained when the antenna element 20 without the deposit 30 is irradiated with electromagnetic waves is represented by reference sign Sr_0. Further, the peak frequency of the peak waveform Sr_0 is represented by the symbol fr_0. The frequency characteristic of the reflected wave is, for example, the result of plotting the reflectance calculated based on the measurement result of the intensity of the reflected wave from the antenna element 20 on the horizontal axis as shown in FIG. 3B. It is. In the following description, as shown in FIG. 3A or the case shown in FIG. 4A to be described later, the entire conductive pattern 22 having the area of the portion of the conductive pattern 22 of the antenna element 20 that overlaps the deposit 30. The peak waveform of the reflected wave obtained from the antenna element 20 when the ratio to the area, that is, the overlapping ratio is a known value is also referred to as a reference peak waveform. The peak frequency of the reference peak waveform is also referred to as a reference peak frequency. The overlap rate in the example shown in FIG. 3A is zero.

  As shown in FIG. 3A, the conductive pattern 22 includes a pair of first elements 23A and 23B arranged with a gap 25 therebetween, and a pair of second elements 24A connected to the pair of first elements 23A and 23B, respectively. , 24B. The pair of second elements 24A, 24B extends in a direction different from the direction in which the pair of first elements 23A, 23B extends, and the distance v between the pair of second elements 24A, 24B is greater than the gap 25. It is configured as such. For example, as shown in FIG. 3A, the pair of first elements 23A and 23B are configured to extend along the first direction D1 and to face each other with a gap 25 in the first direction D1. In FIG. 3A, the dimension of the gap 25 in the first direction D1 is represented by the symbol s. The pair of second elements 24A and 24B extends along a second direction D2 orthogonal to the first direction D1. In this case, the distance v between the pair of second elements 24A and 24B means the distance between the pair of second elements 24A and 24B in the first direction D1. Further, as shown in FIG. 3A, the pair of second elements 24A and 24B are arranged at the end portions of the end portions of the pair of first elements 23A and 23B that are located on the opposite side to the end portions facing each other through the gap 25. It is connected.

  In the antenna element 20 shown in FIG. 3A, based on the dimension s of the gap 25 between the pair of first elements 23A and 23B and the conductivity of the conductive material constituting the conductive pattern 22, FIG. A reference peak frequency fr_0 of the reference peak waveform Sr_0 shown is determined. The dimension s of the gap 25 is set according to the conductivity of the conductive material so that the reference peak frequency fr_0 of the reference peak waveform Sr_0 is in the range of 0.1 THz to 3 THz. For example, when copper or a copper alloy is used as the conductive material constituting the conductive pattern 22, the dimension s of the gap 25 is in the range of 1 μm to 100 μm.

  Next, with reference to FIG. 4A and FIG. 4B, the frequency characteristic of the reflected wave obtained when the deposit | attachment 30 has adhered to the antenna element 20 is demonstrated. FIG. 4A is a plan view showing a state in which an adhering material 30 such as water overlaps the entire conductive pattern 22 of the antenna element 20. FIG. 4B is a diagram showing the frequency characteristics of the reflected wave obtained when the antenna element 20 shown in FIG. 4A is irradiated with electromagnetic waves. In FIG. 4B, when the deposit 30 overlaps the entire conductive pattern 22 of the antenna element 20, that is, when the overlap ratio is 1, the reference wave appears in the frequency characteristics of the reflected wave obtained from the antenna element 20. A peak waveform is represented by a symbol Sr_1. Further, the reference peak frequency of the reference peak waveform Sr_1 is represented by the symbol fr_1. In FIG. 4B, the reference peak waveform Sr_0 of the reflected wave obtained from the antenna element 20 when the deposit 30 is not present is indicated by a dotted line for reference.

  When the conductive pattern 22 is covered with the deposit 30, the reference peak waveform Sr_1 appearing in the frequency characteristics of the reflected wave includes the dimension s of the gap 25 and the conductivity of the conductive material constituting the conductive pattern 22. In addition to the influence of the above, the influence of the deposit 30 covering the conductive pattern 22 is also received. FIG. 4B shows an example in which the reference peak waveform Sr_1 is displaced to the lower frequency side than the reference peak waveform Sr_0 due to the influence of the deposit 30 attached to the conductive pattern 22. The fact that the peak waveform and the peak frequency change due to the influence of the deposit 30 as described above makes it possible to obtain information on the deposit 30 based on whether or not the peak waveform and the peak frequency are changed. It means that.

  For example, the overlapping rate of the deposit 30 with respect to the conductive pattern 22 can be calculated based on the degree of change in the peak frequency. FIG. 7 is a diagram illustrating a result of plotting an overlap rate point P0 = 0 with respect to the reference peak frequency fr_0 and an overlap rate point P1 = 1 corresponding to the reference peak frequency fr_1. When the peak frequency changes linearly according to the overlap ratio from the overlap ratio of 0 to the overlap ratio of 1, connect the points P0 and P1 with a straight line as shown in FIG. Thus, a calibration curve 35 can be obtained. By using this calibration curve 35, it is possible to calculate the overlap rate of the deposit 30 based on the peak frequency obtained when the antenna element 20 with an unknown overlap rate is irradiated with electromagnetic waves.

  Although FIG. 5 shows an example in which the two points P0 and P1 are connected by a straight line, the present invention is not limited to this, and the two points P0 and P1 may be connected by a predetermined curve. Further, the antenna element 20 in various overlapping ratios is irradiated with electromagnetic waves, and the values of the reference peak frequencies corresponding to the various overlapping ratios are measured. Based on these measurement results, the calibration curve 35 is measured. Can be drawn with higher accuracy.

  Hereinafter, an example of an inspection method for inspecting the deposit 30 attached to the container 10 based on changes in the peak waveform and the peak frequency will be described with reference to FIGS. 6 to 8.

Inspection Device First, an inspection device 50 for carrying out an inspection method for inspecting the deposit 30 attached to the container 10 will be described with reference to FIG. The inspection apparatus 50 includes an irradiation unit 51 that irradiates the container 10 with the electromagnetic wave L1, a measurement unit 52 that measures frequency characteristics of the reflected wave L2 that is an electromagnetic wave reflected by the antenna element 20 attached to the container 10, and And an analysis unit 53 that analyzes measurement information obtained by the measurement unit 52. In addition, the irradiation part 51, the measurement part 52, and the analysis part 53 may be comprised integrally, and may be comprised separately.

  As shown in FIG. 6, the inspection apparatus 50 further includes a transport unit 55 that transports an object such as the container 10 to which the antenna element 20 is attached. Thereby, the presence or absence and the degree of adhesion of the deposit 30 in the plurality of containers 10 can be inspected in order.

(Irradiation part)
As the irradiation part 51, what can radiate | emits the electromagnetic wave L1 containing the component from the 1st frequency f1 to the 2nd frequency f2 on the high frequency side rather than the 1st frequency f1 toward the container 10 is used. Both the first frequency f1 and the second frequency f2 are in the range of 0.1 THz to 3 THz, that is, in the terahertz wave band. As long as the peak frequency of the peak waveform appearing in the reflected wave L2 from the antenna element 20 can be specified, the electromagnetic wave L1 radiated from the irradiation unit 51 has components from the first frequency f1 to the second frequency f2. It may contain continuously, or may contain the component from the 1st frequency f1 to the 2nd frequency f2 intermittently.

  Here, “intermittent” means that a plurality of monochromatic terahertz waves are included, and as a result, the electromagnetic wave L1 includes discrete components from the first frequency f1 to the second frequency f2. doing. For example, by superimposing monochromatic terahertz waves emitted from a plurality of monochromatic terahertz light sources, the antenna element 20 may be simultaneously irradiated with the electromagnetic wave L1 including components from the first frequency f1 to the second frequency f2. Good. Alternatively, by changing the frequency of the monochromatic terahertz wave emitted from one monochromatic terahertz light source over time, the electromagnetic wave L1 including the components from the first frequency f1 to the second frequency f2 can be transmitted to the antenna during a certain period. The element 20 may be irradiated.

  As a method for generating a broadband terahertz wave continuously including components from the first frequency f1 to the second frequency f2, for example, terahertz time domain spectroscopy (THz-TDS) can be mentioned. . The terahertz wave generated by the terahertz time domain spectroscopy has a relatively low intensity, for example, about several tens of mW, but has an advantage of excellent stability.

As a method of generating a monochromatic terahertz wave, a method of generating an electromagnetic wave composed of a terahertz wave using a nonlinear optical effect such as optical parametric or difference frequency mixing can be used. In this case, a terahertz wave having a relatively high intensity can be generated. For example, a terahertz wave having an intensity of 300 mW or more or an intensity of 1 W or more can be generated. For this reason, even when a layer having a large thickness is used as the opaque layer of the container 10, the electromagnetic waves returning from the container 10 can be detected with sufficient accuracy. For example, when a generation system that generates electromagnetic waves using nonlinear optical effects such as optical parametric and difference frequency mixing is used, paper having a thickness in the range of 100 μm to 1 cm may be used as the paper constituting the opaque layer. it can.
The nonlinear optical crystal is a crystal that responds nonlinearly, that is, not proportional to the electromagnetic field of light when intense light such as laser light is incident. The nonlinear optical effect is a nonlinear response, that is, a response that is not proportional to the electromagnetic field of light. The optical parametric and difference frequency mixing described above are a kind of nonlinear optical effect.

(Measurement part)
As the measurement unit 52, one that can measure the intensity of the reflected wave L <b> 2 reflected by the conductive pattern 22 of the antenna element 20 for each frequency and obtain the frequency characteristic of the reflected wave L <b> 2 is used. For example, a spectrum analyzer is used as the measurement unit 52.

Authentication Method Next, an inspection method for inspecting the deposit 30 attached to the container 10 using the inspection device 50 will be described.

(Irradiation process)
First, an irradiation step of irradiating the container 10 with the electromagnetic wave L <b> 1 is performed using the irradiation unit 51. Here, as shown in FIG. 7, a case where the deposit 30 overlaps a part of the conductive pattern 22 of the antenna element 20 will be described. As described above, since a terahertz wave having a frequency range of 0.1 THz to 3 THz is used as the electromagnetic wave L, the electromagnetic wave L can pass through the container 10 and reach the antenna element 20.

  As shown in FIG. 7, the irradiation unit 51 radiates the electromagnetic wave L <b> 1 so that the electromagnetic wave L <b> 1 reaches the conductive pattern 22 from the first surface 21 a side of the substrate 21. For example, as shown in FIG. 2, when the antenna element 20 is attached to the first layer 13 in contact with the second layer 14, the measurement unit 52 irradiates the container 10 with the electromagnetic wave L <b> 1 from the third layer 15 side. .

(Measurement process)
Next, the measurement process of measuring the frequency characteristic of the reflected wave L <b> 2 reflected by the antenna element 20 attached to the container 10 is performed using the measurement unit 52. FIG. 8 is a diagram illustrating measurement results of frequency characteristics. In FIG. 8, when the deposit 30 overlaps a part of the conductive pattern 22 of the antenna element 20 as shown in FIG. 7, the peak waveform appearing in the frequency characteristic of the reflected wave L2 obtained from the antenna element 20 is shown. And Sm. Further, the peak frequency of the peak waveform Sm is represented by the symbol fm. In FIG. 8, the peak waveforms Sr_0 and Sr_1 described above are shown by dotted lines for reference. As shown in FIG. 8, the peak waveform Sm is located between the peak waveform Sr_0 when the overlap rate is 0 and the peak waveform Sr_1 when the overlap rate is 1.

(Analysis process)
Next, using the analysis unit 53, an analysis process for analyzing the measurement information obtained by the measurement process is performed. The peak waveform Sm appears in the frequency characteristics of the reflected wave L2 based on the conductivity of the conductive material constituting the conductive pattern 22 of the antenna element 20 and the gap 25 provided in the conductive pattern 22. In the analysis process using the analysis unit 53, the deposit 30 is detected based on the fact that the peak frequency fm of the peak waveform Sm changes according to the presence of the deposit 30 overlapping the conductive pattern 22. For example, based on the fact that the peak waveform Sm obtained in the measurement step is located on the lower frequency side than the above-described reference peak waveform Sr_0 when the overlap ratio is 0, at least the conductive pattern 22 of the antenna element 20 has It can be known that the deposit 30 partially overlaps.

  Moreover, the deposit 30 with respect to the conductive pattern 22 is obtained by comparing the above-described reference peak frequency fr_0 and reference peak frequency fr_1 acquired in advance with the peak frequency fm of the peak waveform Sm obtained in the measurement process. It is also possible to calculate the overlap ratio. For example, the overlapping rate of the deposit 30 with respect to the conductive pattern 22 can be calculated based on the peak frequency fm of the peak waveform Sm obtained in the measurement process and the calibration curve 35 shown in FIG. As described above, according to the present embodiment, not only information on the presence / absence of the deposit 30 but also quantitative information such as information on the ratio of the portion of the antenna element 20 to which the deposit 30 is adhered can be obtained. it can.

  In addition, when the some antenna element 20 is provided so that it may mention later, and only some of the some antenna elements 20 are covered with the deposit | attachment 30, electromagnetic waves L1 are sequentially applied to the plurality of antenna elements 20. The reflected wave L2 obtained in the case of irradiation includes a peak waveform affected by the deposit 30 and a peak waveform not affected by the deposit 30. In this case, based on the fact that the peak waveform of the reflected wave L2 differs depending on the location, it is possible to detect that some deposit 30 is present. Therefore, when a plurality of antenna elements 20 are provided, the adhering material 30 is based on the measurement result of the reflected wave L2 even if the reference peak waveform Sr_0 and the reference peak waveform Sr_1 are not acquired in advance. It is possible to get information about.

  Note that various modifications can be made to the above-described embodiment. Hereinafter, modified examples will be described with reference to the drawings. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above embodiment are used for the parts that can be configured in the same manner as in the above embodiment. A duplicate description is omitted. In addition, when it is clear that the operational effects obtained in the above-described embodiment can be obtained in the modified example, the description thereof may be omitted.

(Modification of conductive pattern)
The reference peak frequency fr_0 of the reference peak waveform Sr_0 when the overlap ratio is 0 and the reference peak frequency fr_1 of the reference peak waveform Sr_1 when the overlap ratio is 1 are 0.1 THz to 3 THz. As long as it exists within the range, the specific shape of the conductive pattern 22 of the antenna element 20 is not particularly limited. Hereinafter, some modified examples of the conductive pattern 22 will be described.

  In the above-described embodiment, an example in which the pair of second elements 24A and 24B of the conductive pattern 22 extend in parallel with each other has been described. However, the present invention is not limited to this, and the pair of second elements 24A and 24B may extend in parallel with each other as shown in FIG.

  In the above-described embodiment, the pair of second elements 24A and 24B are located on the opposite side of the ends of the pair of first elements 23A and 23B through the gap 25. The example connected to the part was shown. However, the present invention is not limited to this, and as shown in FIG. 10, even if the second elements 24A and 24B are connected to the first elements 23A and 23B between the pair of end portions of the first elements 23A and 23B. Good.

  In the above-described embodiment, an example in which the gap 25 is provided between the pair of first elements 23A and 23B extending linearly has been described. However, the present invention is not limited to this, and a gap 25 may be provided between the two rings as shown in FIG. Hereinafter, the embodiment shown in FIG. 11 will be described in detail.

  In the example shown in FIG. 11, the conductive pattern 22 includes a first ring element 27a, a second ring element 27b disposed inside the first ring element 27a, a first ring element 27a, and a second ring element 27b. And a connecting portion 27c for connecting the two. The peak frequency of the peak waveform appearing in the frequency characteristics of the reflected wave L2 is determined according to the gap 25 provided between the first ring element 27a and the second ring element 27b.

  In addition, in FIG. 11, the example in which the one connection part 27c is provided was shown. However, the number and arrangement of the connecting portions 27c are not particularly limited. For example, two connection portions 27c arranged to form a predetermined angle may be provided.

(Example where an overcoat layer is provided)
In the above-described embodiment, an example in which the conductive pattern 22 of the antenna element 20 is in direct contact with the deposit 30 has been described. However, as shown in FIG. 12, the antenna element 20 further includes an overcoat layer 28 provided so as to cover the conductive pattern 22, and the deposit 30 comes into contact with the overcoat layer 28. Good. Even in this case, when the deposit 30 overlaps the conductive pattern 22 when viewed along the normal direction of the base material 21, the peak waveform and peak frequency of the reflected wave L2 change due to the deposit 30. To do. For this reason, it is possible to obtain information about the deposit 30.

(Example in which the antenna element is provided on the wall)
In the above-described embodiment, the example in which the object to which the antenna element 20 is attached is the container 10 that can store a predetermined container is shown. However, the present invention is not limited to this, and the antenna element 20 may be attached to an opaque wall 40 as shown in FIG. FIG. 13 shows an example in which the antenna element 20 is attached to a place other than the outer surface 40x of the pair of walls 40 for partitioning a room or the like, specifically, to the inner surface 40y of the wall 40. The outer surface 40x is a surface facing the room side partitioned by the wall 40. The inner surface 40y is a surface in contact with the space between the pair of walls 40 provided between the two rooms in order to divide the two rooms by the wall 40. Although not shown, the outer surface 40x of the wall 40 may be configured by wallpaper.

  When the wall 40 is opaque, it is not easy to inspect the state of the space between the pair of walls 40. Here, according to the present modification, by attaching the antenna element 20 to the inner surface 40y of the wall 40, information regarding the deposit 30 attached to the antenna element 20 can be obtained. For example, when the deposit 30 is water, it can be inspected whether or not condensation occurs in the space between the pair of walls 40. It is also possible to obtain quantitative information on how much condensation has occurred.

(Example of multiple antenna elements attached to an object)
A plurality of antenna elements 20 may be attached to an object such as the container 10 or the wall 40. For example, as shown in FIG. 14, a plurality of antenna elements 20 including the conductive pattern 22 may be regularly arranged. As a result, information on the deposit 30 attached to the object can be obtained over a wider area.

  FIG. 15 is an enlarged view of a portion surrounded by a dashed line in FIG. A portion surrounded by a one-dot chain line in FIG. 14 represents a section corresponding to one antenna element 20 among the plurality of regularly arranged antenna elements 20. As shown in FIG. 15, the configuration of each antenna element 20 is the same as the configuration of antenna element 20 in the case of the above-described embodiment, and thus detailed description regarding antenna element 20 is omitted.

  FIG. 14 shows an example in which the conductive patterns 22 of the plurality of antenna elements 20 are provided on one common base material 21. That is, an example in which one base material 21 is shared by a plurality of antenna elements 20 is shown. However, the present invention is not limited to this, and the conductive patterns 22 of the plurality of antenna elements 20 may be provided on separate substrates 21.

  In this modification, each antenna element 20 is arranged so that the peak frequency of the electromagnetic wave reflected by one of the two adjacent antenna elements 20 is not affected by the other antenna element 20. ing. In this case, the information regarding the adhesion state of the deposit 30 with respect to each antenna element 20 can be obtained independently for each antenna element 20. For example, in this modification, the inspection apparatus 50 is configured such that the irradiation unit 51 can sequentially irradiate the antenna elements 20 with the electromagnetic wave L1. In this case, for example, at the position where the antenna element 20 having the deposit 30 overlapping the entire conductive pattern 22 is present, the peak waveform Sm equivalent to the above-described reference peak waveform Sr_1 is measured. On the other hand, a peak waveform Sm equivalent to the above-described reference peak waveform Sr_0 is measured at a position where the antenna element 20 where the deposit 30 does not overlap the conductive pattern 22 at all exists. Further, at the position where the antenna element 20 with the deposit 30 overlapping a part of the conductive pattern 22 is present, the peak waveform Sm positioned between the reference peak waveform Sr_0 and the reference peak waveform Sr_1 is measured. Is done. For this reason, the information regarding the distribution of the position of the deposit 30 attached to the object can be obtained with high accuracy. For example, as indicated by dotted lines in FIG. 14, information on the position and extension range of the deposit 30 that overlaps the plurality of antenna elements 20 can be obtained.

  Note that “not affected by the other antenna element 20” means that the reference peak frequency fr_0 or the reference peak frequency fr_1 obtained when there are a plurality of antenna elements 20 and only one antenna element 20 are present. This means that the difference from the reference peak frequency fr_0 or the reference peak frequency fr_1 obtained when present is 5% or less.

  In FIG. 14, a distance between two antenna elements 20 adjacent in the first direction D1 is indicated by a symbol s1. Further, the distance between the first elements 23 of the two antenna elements 20 adjacent in the second direction D2 is indicated by reference sign s2. The distance s 1 and the distance s 2 are set so that the peak frequency of the electromagnetic wave reflected by the one antenna element 20 is not affected by the other antenna element 20. For example, when the dimension s of the gap 25 is in the range of 10 μm to 50 μm, the distance s1 can be set to about 80 μm and the distance s2 can be set to about 180 μm.

In FIG. 15, the dimension of each component of the antenna element 20 in the first direction D1 is represented by reference signs d1 to d6. In addition, the dimensions of the constituent elements of the antenna element 20 in the second direction D2 are represented by symbols d7 to d9. The following examples can be given as combinations of the dimensions d1 to d9 and the dimension s.
(Example 1)
d1 = 40 μm, d2 = 20 μm, d3 = 35 μm, s = 10 μm, d4 = 35 μm, d5 = 20 μm, d6 = 40 μm, d7 = 20 μm, d8 = 20 μm, d9 = 20 μm
(Example 2)
d1 = 40 μm, d2 = 20 μm, d3 = 25 μm, s = 30 μm, d4 = 25 μm, d5 = 20 μm, d6 = 40 μm, d7 = 20 μm, d8 = 20 μm, d9 = 20 μm
(Example 3)
d1 = 40 μm, d2 = 20 μm, d3 = 15 μm, s = 50 μm, d4 = 15 μm, d5 = 20 μm, d6 = 40 μm, d7 = 20 μm, d8 = 20 μm, d9 = 20 μm

  14 and 15 show an example in which the antenna element 20 is configured such that a predetermined gap is provided between the second elements 24 of the two antenna elements 20 adjacent in the second direction D2. It was. However, the present invention is not limited to this, and the second elements 24 of the two antenna elements 20 adjacent in the second direction D2 may be connected as shown in FIG. Even in this case, by appropriately setting the distance s1 and the distance s2, it is possible to suppress the peak frequency of the electromagnetic wave reflected by one antenna element 20 from being influenced by the other antenna element 20. it can. FIG. 17 is an enlarged view of the portion surrounded by the alternate long and short dash line in FIG.

Examples of the combinations of the dimensions d1 to d6, d8 and the dimension s shown in FIG.
(Example 4)
d1 = 40 μm, d2 = 20 μm, d3 = 35 μm, s = 10 μm, d4 = 35 μm, d5 = 20 μm, d6 = 40 μm, d8 = 20 μm
(Example 5)
d1 = 40 μm, d2 = 20 μm, d3 = 25 μm, s = 30 μm, d4 = 25 μm, d5 = 20 μm, d6 = 40 μm, d8 = 20 μm
(Example 6)
d1 = 40 μm, d2 = 20 μm, d3 = 15 μm, s = 50 μm, d4 = 15 μm, d5 = 20 μm, d6 = 40 μm, d8 = 20 μm

14 to 17 show an example in which a plurality of antenna elements 20 are regularly arranged. However, the present invention is not limited to this, and although not illustrated, a plurality of antenna elements 20 may be arranged irregularly.
Unlike the periodic structure disclosed in Patent Document 2 described above, the antenna element 20 is not a type in which the form of arrangement of the plurality of antenna elements 20 affects the peak waveform or peak frequency. Therefore, even if the plurality of antenna elements 20 are irregularly arranged, the attached matter adhered to the object by irradiating each antenna element 20 with the electromagnetic wave L1 in order and measuring the reflected wave L2 Information on the distribution of 30 positions can be obtained with high accuracy.

(Other variations)
Further, in the above-described embodiment and each modification, an example in which the conductive pattern 22 is provided on the base material 21 has been shown. However, the present invention is not limited to this, and the conductive pattern 22 may be provided directly on the surface of an object such as the container 10 or the wall 40. That is, “attaching the antenna element 20 to an object” is not only a form of attaching the base material 21 provided with the conductive pattern 22 to the object, but also forming the conductive pattern 22 directly on the surface of the object. It is a concept that includes forms.

  Further, in the above-described embodiment and each modification, the example in which the electromagnetic wave L <b> 1 is applied to the conductive pattern 22 of the antenna element 20 from the side of the antenna element 20 where the deposit 30 is attached has been shown. For example, when the conductive pattern 22 is provided on the first surface 21 a of the base material 21, the example in which the electromagnetic wave L <b> 1 is irradiated from the first surface 21 a side of the base material 21 to the antenna element 20 has been shown. However, the present invention is not limited to this, and the electromagnetic wave L1 may be applied to the conductive pattern 22 of the antenna element 20 from the opposite side of the antenna element 20 to the side on which the deposit 30 is attached. For example, when the conductive pattern 22 is provided on the first surface 21 a of the base material 21, the antenna element 20 may be irradiated with the electromagnetic wave L <b> 1 from the second surface 21 b side of the base material 21.

  Further, in the above-described embodiment and each modification, an example is shown in which the substance attached to the object is water. However, as long as the frequency characteristics of the reflected wave L2 from the antenna element 20 can be affected, the deposit 30 attached to the antenna element 20 is not particularly limited.

  In addition, although some modified examples with respect to the above-described embodiment have been described, naturally, a plurality of modified examples can be applied in combination as appropriate.

  EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to description of a following example, unless the summary is exceeded.

Example 1
The frequency characteristic of the reflected wave L2 obtained when the antenna element 20 is irradiated with the electromagnetic wave L1 was calculated by simulation. In the simulation, a paper base material was used as the base material 21 of the antenna element 20. Further, as the conductive pattern 22 provided on the first surface 21a of the base material 21, the conductive pattern including the pair of first elements 23A and 23B and the pair of second elements 24A and 24B shown in FIG. 3A described above. 22 was used. The conductive material constituting the conductive pattern 22 was set to a complete conductor having a thickness of 0.2 μm. The widths w1 and w2 of the substrate 21 were each set to 200 μm. The dimension s in the first direction D1 of the gap 25 between the pair of first elements 23A and 23B was set to 10 μm. Further, the width t of the pair of second elements 24A, 24B in the first direction D1 was set to 20 μm.

  The reflected wave L2 measured when the electromagnetic wave L1 is irradiated from the first surface 21a side of the base material 21 to the conductive pattern 22 provided on the first surface 21a of the base material 21 was calculated by simulation. The simulation was performed in two ways when the overlapping ratio of the deposit 30 with respect to the conductive pattern 22 was 0 and 1. Water was used as the deposit 30. The thickness of water adhering to the conductive pattern 22 was set to 0.2 μm. The results are shown in FIG. The peak frequency fr_0 of the peak waveform Sr_0 of the reflected wave L2 obtained when the overlap ratio is 0 was about 0.86 THz. On the other hand, the peak frequency fr_1 of the peak waveform Sr_1 of the reflected wave L2 obtained when the overlap ratio is 1 was about 0.76 THz.

(Example 2)
The dimension 25 of the gap 25 in the first direction D1 of the gap 25 between the pair of first elements 23A and 23B is set to three types of 10 μm, 30 μm, and 50 μm, and the pair of second elements in the second direction D2. Except that the lengths of 24A and 24B were set to 200 μm, the reflected wave L2 obtained when the overlap rate was 0 was calculated by simulation in the same manner as in the case of Example 1 described above. The results are shown in FIG. The peak frequencies of the peak waveform of the reflected wave L2 obtained when the dimension s of the gap 25 is 10 μm, 30 μm, and 50 μm were about 0.82 THz, about 0.95 THz, and about 1.03 THz, respectively.

(Comparative Example 1)
The embodiment described above except that the widths w1 and w2 of the base material 21 are each set to 2000 μm, the dimension s of the gap 25 is set to 300 μm, and the width t of the pair of second elements 24A and 24B is set to 200 μm. As in the case of 1, the reflected wave L2 obtained when the overlap rate is 0 was calculated by simulation. The results are shown in FIG. In Comparative Example 1, the peak frequency of the peak waveform of the reflected wave L2 was about 0.095 THz. That is, the peak waveform did not appear within the range of 0.1 THz to 3 THz.

DESCRIPTION OF SYMBOLS 10 Container 20 Antenna element 21 Base material 22 Conductive pattern 23 1st element 24 2nd element 25 Crevice 28 Overcoat layer 30 Deposit 40 Wall 50 Inspection apparatus 51 Irradiation part 52 Measurement part 53 Analysis part

Claims (14)

An inspection method for irradiating an object with electromagnetic waves and detecting an adhering matter attached to the object,
An antenna element including a conductive pattern provided with a gap is attached to the object,
The inspection method is:
An irradiation step of irradiating the object with the electromagnetic wave;
A measuring step of measuring frequency characteristics of a reflected wave that is the electromagnetic wave reflected by the antenna element attached to the object;
An analysis step for analyzing the measurement information obtained by the measurement step, and
The electromagnetic wave applied to the object includes a component from a first frequency to a second frequency on a higher frequency side than the first frequency continuously or intermittently,
The first frequency and the second frequency are both in the range of 0.1 THz to 3 THz,
In the analysis step, the peak frequency of the peak waveform that appears in the frequency characteristics of the reflected wave based on the conductivity of the conductive material constituting the conductive pattern of the antenna element and the gap provided in the conductive pattern However, the said adhering matter is detected based on changing according to presence of the said adhering matter which overlaps with the said antenna element. The peak frequency of the peak waveform appearing in the frequency characteristics of the electromagnetic wave reflected by the antenna element when the deposit is overlapped with a certain part or all of the conductive pattern of the antenna element is a reference peak frequency. As previously acquired,
In the analyzing step, the conductive pattern of the antenna element is compared by comparing the peak frequency of the peak waveform appearing in the frequency characteristic of the reflected wave measured in the measuring step with the reference peak frequency. The inspection method according to claim 1, wherein a ratio of a portion overlapping the deposit is calculated. A plurality of the antenna elements are attached to the object,
Each antenna element is disposed so that the peak frequency of the electromagnetic wave reflected by one of the two adjacent antenna elements is not affected by the other antenna element. Item 3. The inspection method according to Item 1 or 2. The conductive pattern of the antenna element includes a pair of first elements arranged with the gap therebetween, and a pair of second elements respectively connected to the pair of first elements,
The pair of second elements extends in a direction different from the direction in which the pair of first elements extends, and is configured such that a distance between the pair of second elements is larger than the gap. The inspection method according to any one of claims 1 to 3.   The inspection method according to claim 1, wherein the detected deposit is water. The object is a container formed of paper or opaque resin,
The inspection method according to claim 1, wherein the antenna element is attached to a place other than the outer surface of the container. The object is an opaque wall;
The inspection method according to claim 1, wherein the antenna element is attached to a place other than an outer surface of the wall. An inspection device that irradiates an object with electromagnetic waves and detects an adhering matter attached to the object,
An antenna element including a conductive pattern provided with a gap is attached to the object,
The inspection device includes:
An irradiation unit for irradiating the object with the electromagnetic wave;
A measuring unit that measures frequency characteristics of a reflected wave that is the electromagnetic wave reflected by the antenna element attached to the object;
An analysis unit for analyzing the measurement information obtained by the measurement unit, and
The electromagnetic wave applied to the object includes a component from a first frequency to a second frequency on a higher frequency side than the first frequency continuously or intermittently,
The first frequency and the second frequency are both in the range of 0.1 THz to 3 THz,
In the analysis unit, the peak frequency of the peak waveform that appears in the frequency characteristics of the reflected wave based on the conductivity of the conductive material constituting the conductive pattern of the antenna element and the gap provided in the conductive pattern However, the inspection apparatus is configured to detect the attachment based on a change in accordance with the presence of the attachment that overlaps the antenna element. The peak frequency of the peak waveform appearing in the frequency characteristics of the electromagnetic wave reflected by the antenna element when the deposit is overlapped with a certain part or all of the conductive pattern of the antenna element is a reference peak frequency. As previously acquired,
In the analysis unit, the conductive pattern of the antenna element is compared by comparing the peak frequency of the peak waveform appearing in the frequency characteristic of the reflected wave measured in the measurement unit with the peak frequency for reference. The inspection apparatus according to claim 8, wherein a ratio of a portion overlapping the deposit is calculated. A plurality of the antenna elements are attached to the object,
Each antenna element is disposed so that the peak frequency of the electromagnetic wave reflected by one of the two adjacent antenna elements is not affected by the other antenna element. Item 10. The inspection device according to Item 8 or 9. The conductive pattern of the antenna element includes a pair of first elements arranged with the gap therebetween, and a pair of second elements respectively connected to the pair of first elements,
The pair of second elements extends in a direction different from the direction in which the pair of first elements extends, and is configured such that a distance between the pair of second elements is larger than the gap. The inspection apparatus according to any one of claims 8 to 10.   The inspection apparatus according to any one of claims 8 to 11, wherein the detected deposit is water. The object is a container formed of paper or opaque resin,
The inspection apparatus according to any one of claims 8 to 12, wherein the antenna element is attached to a place other than an outer surface of the container. The object is an opaque wall;
The inspection apparatus according to any one of claims 8 to 12, wherein the antenna element is attached to a place other than an outer surface of the wall.