Inspection device and inspection system

Abstract

To detect a foreign substance mixed in a filamentous body, which is smaller than before.SOLUTION: An inspection device 1 for a filamentous body F comprises: an oscillator 10 that emits electromagnetic waves having a frequency of 30GHz or more; a first waveguide 20 that is connected at one end to the oscillator 10 and forms a waveguide for the electromagnetic waves; a cavity resonator 30 that has an inlet 31 to which the other end of the first waveguide 20 is connected and into which the electromagnetic waves are introduced, a cavity 32 in which the electromagnetic waves resonate in a specific oscillation mode, an outlet 33 from which the electromagnetic waves are derived from the cavity 32, and a communication outlet 34 that forms a communication channel 35 through which the filamentous body F is passed; a second waveguide 40 that is connected at one end to the outlet 33 and guides the electromagnetic waves from the cavity resonator 30; a receiver 50 that receives the electromagnetic waves derived from the cavity resonator 30; and a calculation section 60 that evaluates a state of the filamentous body F on the basis of fluctuations in the electromagnetic waves within the cavity resonator 30.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an inspection device and an inspection system. [Background technology]

[0002] In the manufacturing line of filamentous materials such as glass fiber, the equipment, surrounding environment, manufacturing process, etc. Due to this, foreign matter such as metal pieces may become mixed in or adhere to the filament. As a method for detecting foreign objects such as metal fragments contained in an object, a metal detector using the Doppler effect A detector may be used. Also, cavity resonance may be used to detect foreign objects contained in the filaments. In the conventional inspection apparatus, electromagnetic waves are irradiated onto the filament to be inspected. When a detection wave (electromagnetic wave) is incident on the device, the internal medium of the cavity resonator and the dielectric constant of the test object are Resonance occurs at a frequency determined by the dielectric constant, and the inspection object contains a foreign object with a different dielectric constant. When a foreign object is detected, this frequency changes, and by detecting this change, the foreign object can be detected. This is possible (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-216687 A [Patent Document 2] Japanese Patent Application Publication No. 6-66735 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when using a metal detection method that uses the Doppler effect, the detection accuracy is In order to ensure this, it is necessary to keep the transport speed of the inspection object at a certain level or higher. When the conveying speed of the object is kept constant, it is possible to determine at which position the foreign object is present in the object. As a result, some of the products tested had foreign matter mixed in. It became necessary to discard even parts that were not yet used.

[0005] In addition, the metal detection method using the Doppler effect and the conventional method described in the above patent document There is a limit to the size of foreign objects that can be detected by inspection equipment. Microwaves are supplied to a waveguide having a through hole through which the object to be inspected contains a foreign object. The increased reflected waves can be used to detect foreign objects such as metal fragments. In addition, Patent Document 2 discloses a hollow space having a through hole through which a filament to be inspected passes. Microwaves are supplied into the resonator, and if the inspection object contains a foreign object, a The fluctuation in the waveform of the standing wave generated by the sensor can be used to detect foreign objects such as metal fragments. It is listed.

[0006] Here, the strength of the reflected wave weakens as the size of the foreign object becomes smaller. In the described technology, the smaller the foreign object, the more difficult it is to detect. The magnitude varies depending on the frequency band of the electromagnetic waves used, as described in Patent Documents 1 and 2. The frequency band of microwaves is between 3GHz and 30GHz. The size of foreign objects such as metal pieces that can be detected using electromagnetic waves is several millimeters, with a minimum of 10 Therefore, by applying electromagnetic waves in this frequency range, When detecting foreign matter that has entered the filament, it is necessary to find foreign matter that exists continuously for a certain length along the length of the filament. As described above, the detection accuracy and detectability of the above-mentioned conventional technology are poor. The size of the foreign objects that could be removed was too large and the results were not satisfactory.

[0007] In order to detect smaller foreign objects, it is an electromagnetic wave with a shorter wavelength than microwaves, and is 30 It is expected that millimeter waves with frequencies of GHz or more will be used. Simply replacing the conventional radio waves with millimeter waves to create an inspection device would not be sufficient to function as an inspection device. For example, it was found that using electromagnetic waves with shorter wavelengths would not It is difficult to steadily generate a specific electromagnetic wave that is effective for detecting foreign objects in a space through which the object passes. I realized it was going to be difficult.

[0008] Therefore, the present invention is capable of detecting foreign matter that is smaller than that detected in the past among foreign matter that has become mixed in the filament. An object of the present invention is to provide an inspection device and an inspection system. [Means for solving the problem]

[0009] One aspect of the present invention is a filament inspection device, comprising: An oscillator that emits electromagnetic waves with a frequency of 30 GHz or more; a first waveguide having one end connected to the oscillator and forming a waveguide for an electromagnetic wave; The other end of the first waveguide is connected to an inlet through which the electromagnetic wave is introduced. The electromagnetic wave is oscillated in a specific vibration mode. A cavity that resonates at a certain frequency, an outlet for guiding electromagnetic waves from the cavity, and a passage for passing the filament. a cavity resonator having a communication port forming a cavity resonator having a cavity opening; a second waveguide having one end connected to the outlet for guiding the electromagnetic wave from the cavity resonator; a receiver for receiving the electromagnetic wave guided from the cavity resonator; a calculation unit that evaluates a state of the filament based on a fluctuation of the electromagnetic wave in the cavity resonator; The inspection device includes:

[0010] As mentioned above, the detectable size of a foreign object depends on the wavelength of the detection wave (electromagnetic wave). Conventional inspection equipment uses microwaves (wavelength: several mm to 30 cm) as a detector. The minimum size of the foreign matter that can be detected is about several hundred microns, and it is difficult to detect foreign matter smaller than this. In this respect, electromagnetic waves with frequencies above 30 GHz, such as millimeter waves, A waveguide, a cavity resonator, and a waveguide are arranged between the oscillator and the receiver, and the cavity resonator The presence or absence of foreign objects can be detected by measuring the degree of fluctuation of the electromagnetic waves within the cavity resonator. According to the inspection apparatus of the present embodiment, the size of the defect is smaller than several hundreds of μm. It is now possible to detect foreign objects, for example, foreign objects of a few micrometers (μm) in size.

[0011] Inside the cavity resonator in the above-mentioned inspection device, from the inlet to the outlet of the cavity One or more standing wave antinodes may be generated by the above-mentioned arrangement.

[0012] The cavity resonator in the above-mentioned inspection device has a standing wave generated inside the cavity with the number of loops n may be configured such that is an odd number.

[0013] In the above-mentioned inspection device, the cavity resonator has a number of antinodes of the standing wave generated inside the cavity. It may be configured such that n is 3 or greater.

[0014] In the above-mentioned inspection device, the connecting passage is a passage for connecting the filament to the cavity in a vibration mode. The antinode may be formed at a position passing through a predetermined range from the antinode of the standing wave.

[0015] In the above-mentioned inspection device, the cavity resonator may have a rectangular parallelepiped cavity. .

[0016] In the above-mentioned inspection device, the inlet and outlet are formed by an iris. This is also fine.

[0017] In the above-mentioned inspection device, the inner surface of the cavity may be made of metal.

[0018] In the above-mentioned inspection device, the cavity resonator has a plurality of holes for passing a plurality of filaments. In addition, a communication passage may be provided.

[0019] In the above-mentioned inspection device, each of the plurality of communication paths is configured to allow the filament to pass through the cavity. The antennas are provided at predetermined intervals so as to pass through a region within a predetermined range from the antinode of the standing wave generated. It may be possible.

[0020] In the above-mentioned inspection device, the calculation unit calculates the intensity of a predetermined resonance frequency included in the electromagnetic wave. Based on at least one of the fluctuation of the frequency of the electromagnetic wave and the fluctuation of the frequency of the electromagnetic wave, It may be an evaluation of a physical condition.

[0021] In the above-mentioned inspection device, the oscillator has a first range centered on a predetermined resonant frequency. The electromagnetic wave source may generate a continuous wave including the above frequencies.

[0022] In the above-mentioned inspection apparatus, the oscillator generates a series of resonant frequencies. The antenna may be one that generates a wave.

[0023] In the above-mentioned inspection device, the calculation unit receives the electromagnetic wave generated by the oscillator and via the cavity resonator. The first chirp wave received by the receiver and the chirp wave emitted by the oscillator have a frequency that varies with time. The difference in frequency between the first chirp wave and the second chirp wave, which has a different degree of fluctuation in the number of chirp waves, and the difference in signal strength are small. The presence or absence of an abnormality in the filaments may be evaluated based on at least one of them.

[0024] The inspection device as described above is disposed inside the cavity resonator, and the communication passage and the inside of the cavity resonator are A protective tube may be provided to separate the hollow portion from the housing.

[0025] The communication port in the above-mentioned inspection device is determined by the cutoff frequency of the waveguide. The size of the electromagnetic wave is set so that it does not leak out of the cavity. This is also fine.

[0026] In the above-mentioned inspection device, the inner diameter of the inlet and the inner diameter of the outlet are 15% of the cross-sectional area of ​​the cavity provided in the cavity resonator in the direction perpendicular to the line segment connecting It may be small.

[0027] Further, an inspection system according to one aspect of the present invention includes a plurality of the above-described cavity resonators, The filament is configured to pass through communication passages of two or more of the plurality of cavity resonators. This is what is being considered. Effect of the Invention

[0028] According to the present invention, it is possible to detect foreign matter that has become mixed in a filament and is smaller than that detected in the past. can be done. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a diagram illustrating a configuration example of an inspection device. [Diagram 2] 1A to 1C are diagrams illustrating examples of the shape of a cavity resonator. [Diagram 3] 13 is an image showing an example of the electric field intensity in a cavity resonator when the number of loops is n=3. [Figure 4] FIG. 13 is a diagram showing how a filament is passed through a communication passage of a cavity resonator. [Diagram 5] 11 is a diagram showing electric and magnetic field lines when the communication port is viewed from above. FIG. [Figure 6] FIG. 13 shows the electric field intensity plot of TM11. [Figure 7] 1 is a graph showing the relationship between the radius of a waveguide and the cutoff frequency of a TM11 mode. [Figure 8] 13 is a graph showing a comparison of spectra when the iris diameter is changed. [Figure 9] 1 is a graph showing the relationship between the iris diameter and the Q value (sensitivity to a foreign object M). [Figure 10] Graph showing (A) an example of a waveform of a chirp wave, and (B) an example of change in frequency of the chirp wave. [Figure 11] FIG. 1 is a schematic diagram showing a configuration in which two different chirp waves are radiated from separate oscillators. [Figure 12] (A) A graph showing an example of two different chirp waves, and (B) a graph showing the progress of the frequency difference between the two different chirp waves. [Figure 13] Graph (A) shows the relationship between the difference in frequency (IF frequency) of two different chirp waves and the intensity of chirp wave 1, and graph (B) shows the relationship between the original frequency of chirp wave 1 and the intensity of chirp wave 1. [Figure 14] 11 is a graph showing an example of changes in resonance frequency of a normal portion of a filament and a portion containing a foreign object. [Figure 15] 11 is a graph showing examples of detected waveforms of a normal portion of a filament and a portion containing a foreign object in Example 1 of the present disclosure. [Figure 16] 1A and 1B are a perspective view and an enlarged view of a part of a cavity resonator designed in a second embodiment of the present disclosure. [Figure 17] 11 is a graph showing examples of detected waveforms of a normal portion of a filament and a portion containing a foreign object; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, preferred embodiments of an inspection device and an inspection system according to the present invention will be described with reference to the drawings. The following will now be described in detail with reference to FIGS. 1 to 13.

[0031] The inspection device according to the present disclosure is adapted to inspect a variety of materials, such as glass fibers, that are manufactured through various manufacturing processes. The measurement target is filamentous bodies F such as metal fragments due to equipment, surrounding environment, manufacturing process, etc. In order to check whether there are any abnormalities such as the inclusion or attachment of foreign matter M In this inspection device, electromagnetic waves are irradiated onto the filament F in the cavity resonator, and the internal medium Resonance occurs at a certain frequency determined by the dielectric constant of the material and the filament F, and The principle is to detect foreign matter M by detecting the change in frequency that occurs when the foreign matter M is present. The inspection will be carried out. In addition, the inspection device according to the present disclosure generates a standing wave of an electromagnetic wave having a predetermined resonant frequency in a cavity. It is generated inside the oscillator. In this disclosure, the frequency is 3 GHz or more and less than 30 GHz, and the wavelength is The electromagnetic waves with a frequency band of approximately 10 centimeters to 1 centimeter are Microwaves have a frequency of 30 GHz or more and less than 300 GHz, and a wavelength of millimeters. Electromagnetic waves in the range of 30 GHz are called millimeter waves. However, millimeter waves and microwaves are strictly separated into the range of 30 GHz and 30 GHz. Needless to say, this is not defined as the boundary.

[0032] The inspection device 1 of this embodiment includes an oscillator 10, a first waveguide 20, a cavity resonator 30, and a second The device is configured to include a waveguide 40, a receiver 50, and a calculation unit 60 (see FIG. 1, etc.). .

[0033] (Oscillator) The oscillator 10 includes a predetermined range (first range) of frequencies centered on a predetermined resonant frequency. In this embodiment, the device mainly generates millimeter waves (30 GHz or higher). The oscillator 10 is constructed assuming the use of electromagnetic waves in the frequency band (below 300 GHz). However, it is of course possible to apply electromagnetic waves with frequencies of 300 GHz or higher.

[0034] (waveguide) The first waveguide 20 is for guiding the electromagnetic wave generated in the oscillator 10 to the cavity resonator 30. One end of the component is connected to the oscillator 10 and the other end is connected to the cavity resonator 30. (See FIG. 1.) The second waveguide 40 guides the electromagnetic wave from the cavity resonator 30 to the receiver 50. One end of the member is connected to the cavity resonator 30, and the other end is connected to the receiver 50. The first waveguide 20 and the second waveguide 40 are connected to each other (see FIG. 1). The configuration may be the same as that used in the conventional inspection device. These are shown in a simplified form in the schematic diagram shown at 1. The cross-sectional areas of the first waveguide 20 and the second waveguide 40 are generated inside the cavity resonator 30. The resonant frequency of the electromagnetic wave can be determined by the resonant frequency of the electromagnetic wave. The waveguide 20 and the second waveguide 40 have the same dimensions a and b (see FIG. 2) has a rectangular cross section. The first waveguide 20 and the second waveguide 4 The cross-sectional area and cross-sectional shape of the first cavity resonator 30 may not be the same as those of the first cavity resonator 30. The lengths of the first waveguide 20 and the second waveguide 40 are not particularly limited. The second waveguide 40 may be, for example, The dimensions correspond to electromagnetic waves of a specific frequency band as specified in the Electromagnetic Compatibility Alliance (EMC) standard. A waveguide (waveguide) having a shape having a given shape can be appropriately selected and used.

[0035] (cavity resonator) The cavity resonator 30 is made of a housing (structural body) 39 having a cavity 32 formed therein. In the cavity 32, there is a medium that transmits electromagnetic waves in the resonant frequency band well. In this embodiment, the medium is air. The cavity resonator 30 generates a standing wave (stationary wave) in the cavity 32. The standing wave generated in the cavity 32 has a predetermined resonant frequency. At least the inner circumferential surface of the cavity 32 is made of metal. In the embodiment, the housing 39 is made of metal walls. Also, the housing 39 has a rectangular parallelepiped shape with the dimensions shown in FIG. Taking a certain cavity resonator 30 as an example, the resonant frequency f is expressed by the following formula 1. As described above, the dimensions of the cavity resonator 30 are small, and the medium (e.g., the internal space of the cavity resonator 30) is small. The lower the dielectric constant of the material (e.g., air), the higher the frequency f of the electromagnetic waves generated in the cavity resonator 30. The dimensions a, b, and c shown in Fig. 2 are the dimensions of the cavity. The dimensions of 32, i.e., the dimensions of the space that generates a standing wave having a predetermined resonant frequency component, are show.

number

[0036] Here, if the dimensions are reduced to miniaturize the cavity resonator 30, when millimeter waves are used, Even if the cavity resonator 30 is used, a standing wave having a predetermined resonant frequency can be generated inside the cavity resonator 30. In addition, the occurrence of standing waves adjusts the electric field intensity distribution inside the cavity resonator 30. As a result, the amplitude of the standing wave having a predetermined resonant frequency can be increased, i.e. That is, the electric field strength can be strengthened in a specific range (area). In the cavity resonator 30, the yarn to be measured containing the foreign object M is placed in a relatively strong electric field strength range. When the object F passes through, the range of change in frequency or intensity of the electromagnetic waves that appears becomes larger, and the detection accuracy becomes higher. The degree can be improved.

[0037] As an example, in this embodiment, the dimensions shown in FIG. 2 are a=3.0 mm and b=1.5 mm. Also, n=3, that is, the number of loops of the standing wave is odd, so c=7.2mm. A cavity resonator 30 having a resonant frequency of 79 GHz was used. The rectangular cavity resonator 30 is made in accordance with the EIA standard. A structure conforming to WR12 of the JIS C 1992-1992 and having dimensions a = 1.549 mm, b = 3.099 mm. A structure adjusted to m may be used. The resonant frequency of 79 GHz is Due to the presence and dimensions of the inlet 31 and outlet 33, which will be described later, and the dimensions of the communication port 34, It goes without saying that there will be a deviation of several GHz.

[0038] The above dimensions a, b, and c are merely examples. The dimensions of the cavity resonator 30 may vary depending on its internal dimensions. It is possible to appropriately adjust the frequency based on the desired electromagnetic waves to be generated. The inspection device is capable of detecting smaller foreign objects and has improved detection accuracy compared to conventional methods. do.

[0039] The inspection device 1 will be described in more detail below. Compared to conventional devices, it uses millimeter waves in the high frequency band. The sensitivity to foreign matter M, such as metal fragments, contained in the filament F is improved, while the filament F It is difficult to generate a predetermined electromagnetic wave inside the cavity resonator 30 (cavity 32) through which the electromagnetic wave passes. For example, there have been cases where the accuracy of the electromagnetic wave introduction method, leakage of electromagnetic waves from the cavity resonator 30, etc. In some cases, it may be difficult to generate a desired electromagnetic wave within the cavity resonator 30.

[0040] From the above viewpoint, a predetermined electromagnetic wave is generated in a space through which the filament F to be inspected passes. In order to achieve this, it is preferable to properly introduce the electromagnetic waves into the space (cavity 32). In the embodiment, the inspection device 1 transmits an electromagnetic wave generated by an oscillator 10 through a first waveguide 20, The light is introduced into the cavity 32 of the cavity resonator 30 through the inlet 31, and then exits through the outlet 33 and the second waveguide 40. According to the above, the oscillator 10, the receiver 50 receives the signal via the oscillator 10. 0, and the electromagnetic wave waveguides (the first waveguide 20 and the second waveguide 40) are A space in which electromagnetic waves of a certain vibration mode must be generated in order to pass through (cavity resonator 3 0) in the cavity 32, so that the desired electric current can be generated in the cavity 32. It becomes easier to generate magnetic waves.

[0041] In this embodiment, when applying electromagnetic waves with a frequency of 30 GHz or more, the following The cavity resonator 30 having such a configuration is constructed to improve a predetermined detection accuracy.

[0042] (Overview of the cavity resonator) The cavity resonator 30 of this embodiment includes an inlet 31 through which an electromagnetic wave is introduced, a cavity 32, and a An outlet 33 through which the electromagnetic wave is output from 32, and a communication passage 35 through which the filament F passes are formed. It has a pair, that is, at least two communication ports 34 (see FIG. 1, etc.).

[0043] The shape of the cavity 32 is not particularly limited, but may be, for example, a rectangular parallelepiped shape. The outlet 33 is disposed so as to face the inside of the cavity 32. 32 has one or more antinodes from the inlet 31 to the outlet 33, and the number n of the antinodes is odd. As an example, in this embodiment, the cavity 3 is configured to generate a standing wave having a number of wavelengths. The number of loops of the standing wave generated inside 2 is set to 3 (see Figure 3), and the electromagnetic wave has a specific amplitude. The resonance is set to the dynamic mode. Among the three nearly circular electric field intensities shown in FIG. , the intensity is stronger in the central part. Because the electric field intensity image, which was originally expressed in color, is now expressed in shades of black and white, The electric field intensity appears strong on the outer edge of the circle, but the actual electric field intensity varies from It has become weaker.

[0044] The communication port 34 is provided in the housing 39 of the cavity resonator 30 as a hole through which the filament F can pass. The filament F is passed through a communication passage 35 (see FIG. 4, etc.). The body F moves from top to bottom (or bottom to top) in the communication passage 35 at a predetermined speed. , and passes through (see FIG. 1 and FIG. 4). That is, the filament F passes through the cavity 32 of the cavity resonator 30. In this embodiment, the casing 39 also passes through in the direction of the amplitude of the standing wave generated in the cavity 32. The widest surface is the upper surface (indicated by reference numeral 39a) in FIG. 2, which has a width a and a length c. A pair of communication ports 34 are provided on the lower surfaces, which are the opposing surfaces. The communication path 35 formed by the above-mentioned is a path through which the electric field strength of the standing wave formed in the cavity resonator 30 is strong. In other words, the pair of communication ports 34 are preferably formed so as to pass through the The communication path 35 is configured such that the antinode peak of the standing wave formed in the cavity resonator 30 occurs. It is preferable that the number of loops n of the standing wave generated inside the cavity 32 is 3. In this embodiment (see FIG. 3), the middle of the three antinodes with the strongest electric field strength is The upper surface 39a and the lower surface 39b of the housing 39 are arranged so that the communication passage 35 passes through the central portion of the belly of the housing 39. A pair of communication ports 34 are provided in the center of the housing (see FIG. 4).

[0045] A protective tube 36 may be provided to separate the communication passage 35 from the cavity 32 in the cavity resonator 30. The protective tube 36 is preferably made of a material that absorbs little electromagnetic waves generated in the cavity 32. Specific examples of the material include ceramic and resin. 6 is a material that will not damage the filament F and will not abrade even if it comes into contact with the filament F. It is preferable that the material does not wear or has as little friction resistance as possible. For the type of filament F, ceramic is more preferable in light of the above conditions, especially for the object to be inspected. When the filaments F are glass fibers, they are most preferably ceramic. In this way, by providing the protective tube 36, dust and the like generated in the external environment can be prevented from entering the cavity resonator 30. As a result, the inspection device 1 can be installed in a manufacturing line and Even when used intentionally, high inspection accuracy can be maintained.

[0046] In this embodiment, one communication passage 35 is formed from a pair of communication ports 34. This is merely one example. For example, a plurality of communication paths 35 may be provided, and a plurality of filaments F may be It is also possible to allow the two gases to pass through the communication passages 35 at the same time. For example, if the number of loops of the standing wave is n=3 as in this embodiment, the three loops with the strongest electric field strength are Each of the communication passages 35 passes through a region within a predetermined range from each of the antinodes at a predetermined interval. It is preferable to provide each communication port 34 so that the pair of communication ports 34 are spaced apart from each other (see FIG. 4). Each of the plurality of communication paths 35 formed by the cavity resonator 30 is a fixed It is formed at the point where the antinode peak of the standing wave occurs.

[0047] (Diameter of communication port) When inspecting the filament F for foreign matter, the cavity resonator 30 has a connecting tube for passing the filament F. A vent 34 must be provided to provide communication between the cavity 32 and the outside environment. 34, the larger the aperture, the easier it is to pass the filament F through and the better the operability, but especially in the millimeter wave band When the electromagnetic wave is used for foreign body inspection, as described above, the electromagnetic wave may leak from the communication port 34. Therefore, the effect on the electromagnetic waves in the cavity resonator 30 is greater than that of the conventional method, and the desired electromagnetic waves useful for the inspection are not easily detected. Therefore, it is difficult to generate a large amount of heat in the cavity resonator 30 including the diameter of the communication port 34. The effect on inspection accuracy due to the structure becomes more significant than before. It is desirable to have a hole diameter as large as possible while suppressing the leakage of electromagnetic waves. An example of a procedure (flow) for determining the size of the pores is shown below. 1. The resonant frequency of the electromagnetic wave (standing wave) generated within the cavity resonator 30 is determined. 2. The communication port 34 of the filament F is located directly above the antinode of the electromagnetic wave (standing wave) having the above-mentioned resonant frequency. do. 3. The length of the communication opening 34 (in other words, the length of the metal wall of the cavity resonator 30 in which the communication opening 34 is formed) In terms of thickness, the communication port 34 of the filament F can be electromagnetically treated in the same way as a circular waveguide. Consider that it will become possible. 4. From the above resonant frequency and the length of the circular waveguide, the propagation mode within it is identified. 5. The k value in the cutoff frequency formula (Equation 2) is determined by the identified propagation mode. circle. 6. Let fc be the upper limit of the frequency contained in the electromagnetic wave generated within the cavity resonator 30, and The hole diameter (radius) r of the communication port 34 is determined by the following Equation 2 of the frequency.

number

[0048] The above decision procedure (flow) is supplemented below (see Figures 6 and 7). The communication port 34 is regarded as a cutoff waveguide, and the electromagnetic waves (electric power) leaking from the cavity 32 are As described above, the communication port 34 is formed in the housing constituting the cavity resonator 30. It functions as a circular waveguide with a length equal to the thickness of the body (metal wall). Here, the circular waveguide is As the term cutoff waveguide suggests, it acts as a high-pass filter and cuts out frequencies above a certain frequency. Therefore, the diameter of the circular waveguide (communication port 34) is set to a predetermined value. By adjusting the diameter, leakage of electromagnetic waves from the cavity resonator 30 is prevented, and the inside of the cavity resonator 30 is It is possible to generate electromagnetic waves of a desired vibration mode in the portion.

[0049] As mentioned above, the value of the constant k in the cutoff frequency formula (Equation 2) depends on the propagation mode in the waveguide. The propagation mode is determined by the radius and length of the waveguide. For example, As mentioned above, the standing wave with an electromagnetic wave of a frequency band of about 79 GHz is resonated in a cavity. When the length of the communication port 34 (circular waveguide) is 1.2 mm, The propagation mode is TM mode (Transverse Magnetic mode). In general, as shown in FIG. 6, the simulation results show that the communication port 34 The mode of the electromagnetic wave passing through the communication port 34 is TM11 (a mode in which there are two loops of the electric field inside the communication port 34). It has been confirmed that the dominant

[0050] In this embodiment, as an example, as described above, a resonant frequency is provided in the cavity resonator 30. When generating electromagnetic waves of several 79 GHz, taking into account the generation error of the electromagnetic waves, Cutoff frequency fc (the upper limit of the frequency included in the electromagnetic wave generated within the cavity resonator 30) is set to 82GHz, and electromagnetic waves with frequencies above this cutoff frequency fc are allowed to pass through. The radius of the communication opening 34 that does not cause the The radius of the through hole 34 must be 2.23 mm or less. The upper limit of the hole diameter of the communication port 34 through which the air passes is obtained. The upper limit of the frequency that the oscillator 10 can generate may be set. stomach.

[0051] (Inlet and outlet) The inlet 31 is a portion where the electromagnetic wave is introduced into the cavity 32 via the first waveguide 20, and the outlet 32 ​​is a portion where the electromagnetic wave is introduced into the cavity 32. The inlet 33 is a portion through which the electromagnetic waves are led out from the cavity 32. are arranged to face each other, and are arranged in the cavity 32 perpendicular to the traveling direction of the electromagnetic wave. More specifically, in this embodiment, the introduction The inlet 31 and outlet 33 are sized perpendicular to the direction of propagation of the electromagnetic wave in the rectangular parallelepiped cavity 32. It has an area smaller than the cross-sectional area of ​​the cavity 32 defined by the dimensions a and b.

[0052] The inlet 31 and the outlet 33 are provided with a standing wave having a predetermined resonant frequency in the cavity 32. In order to generate waves, the device is constructed to be large enough that electromagnetic waves of a certain frequency do not leak out. In other words, if the inlet 31 and the outlet 33 are too large, The electromagnetic waves leaking from the outlet 33 cause a predetermined resonant frequency in the cavity 32. This makes it difficult to generate standing waves. When the amount of electromagnetic waves passing through the first waveguide 20 and the second waveguide 40 becomes excessive, the first waveguide 20 and the second waveguide 40 resonate. From the above viewpoint, in this embodiment, the inlet 3 1 and the outlet 33 are configured to have an area smaller than 15% of the cross-sectional area of ​​the cavity 32. The calculation of the upper limit of the area of ​​the inlet 31 and the outlet 33 will be described later. do.

[0053] The inlet 31 and the outlet 33 are arranged by forming a predetermined through hole in the cavity resonator 30. between the cavity resonator 30 and the first waveguide 20 or the second waveguide 40. Alternatively, the light receiving portion may be formed by disposing an iris having a through hole of a certain area. In this embodiment, the inlet 31 and the outlet 33 are formed by an iris (small hole). There are.

[0054] The members forming the inlet 31 and the outlet 33 are conductive so that electromagnetic waves do not penetrate them. It is preferable that the inlet 31 and the outlet 33 are made of a single material. The thickness of the iris should be thin while still being long enough to prevent electromagnetic waves from passing through. Such a length is, for example, 1 μm or more and less than 100 μm. In this example, an inlet 31 and an outlet 33 are formed in a metal plate having a thickness of 50 μm to serve as an iris.

[0055] An example of how to determine the upper limit of the area (size) of the inlet 31 and the outlet 33 is as follows. As described above, the cavity resonator 30 having a given dimension is With a standing wave having a resonant frequency of 79 GHz generated inside, the inlet 31 and the When the area of ​​the outlet (iris) 33 is changed, the inlet 31 and outlet 32 ​​are changed as shown in FIG. The Q factor varies depending on the area of ​​the iris 33 (diameter of the iris). A large Q value means that the waveform of the electromagnetic wave with the resonant frequency as its peak is relatively steep. This shows that the waveform of the electromagnetic wave changes significantly when an object containing a foreign object M passes through. Therefore, the sensitivity to the foreign object M is high. Here, the detection of the foreign object using the cavity resonator 30 generally requires the following: In principle, the Q value must be greater than 1000. The area (iris diameter) of the inlet 31 and outlet 33 is preferably φ0.9 mm or less. It is preferable that this is 15% or less of the cross-sectional area of ​​the cavity 32. The inner diameter of the inlet 31 and the inner diameter of the outlet 33 of the cavity resonator 30 are 15% of the cross-sectional area of ​​the cavity 32 provided in the cavity resonator 30 in the direction perpendicular to the connecting line segment. % is preferable.

[0056] The lower limit of the area (iris diameter) of the inlet 31 and the outlet 33 is greater than 0. There is no particular limitation as long as the electromagnetic wave can be measured. In order to ensure a certain level of strength, the inlet 31 and outlet 33 have a predetermined size or larger. It is preferable to do so. As described above, the smaller the inlet 31 and outlet 33 are, the more the air that passes through these through holes is absorbed. For example, in the first waveguide 20 and the second waveguide 21 as described above, The cross-sectional areas of the tube 40 and the cavity resonator 30 are dimension a=3.0 mm and dimension b=1.5 mm. When an electromagnetic wave having a vibration frequency of 79 GHz is used, the inlet 31 and the outlet 33 The comparison of the electromagnetic wave level when the area of ​​the oscillator is changed is shown in Figure 8. The ratio of the intensity of the electromagnetic wave generated by the transmitter 10 to the intensity of the electromagnetic wave received by the receiver 50 is taken. This shows the transmittance of electromagnetic waves passing through the inlet 31 and outlet 33. For each size of the inlet 31 and the outlet 33 (diameter of the opening of the inlet 31 and the outlet 33), This shows the transmittance of electromagnetic waves. As shown in FIG. 8, the smaller the areas of the inlet 31 and outlet 33, the more the air passes through them. The intensity of the electromagnetic waves after the impact is small. The dynamic range is approximately -110 dB (the -110 dB line in Figure 8). In light of this, if the diameter of the inlet 31 and the outlet 33 is less than 0.3 mm, Therefore, the strength of the electromagnetic waves received by the receiver 50 is weak, and there are areas outside the measurement range. From the above, the diameter of the inlet 31 and the outlet 33 is preferably φ0.3 mm or more. According to this, the cross-sectional areas of the first waveguide 20, the cavity 32, and the second waveguide 40 are The area of ​​the inlet 31 and the outlet 33 is preferably 1.6% or more.

[0057] The above-described inlet 31 and outlet 32 ​​of the cavity resonator 30 are The upper limit of the aperture is determined by the ratio of the areas of the first waveguide 20, the cavity 32, and the second waveguide 33. The ratio of the area of ​​the inlet 31 and the outlet 33 to the cross-sectional area of ​​the waveguide 40 is determined by the ratio of the area of ​​the inlet 31 and the outlet 33 to the cross-sectional area of ​​the waveguide 40. The lower limit of the diameter depends on the shapes of the first waveguide 20, the cavity resonator 30, and the second waveguide 40, and It can be applied even if the dimensions change.

[0058] (Receiver) The receiver 50 receives the electromagnetic wave that is guided out of the cavity resonator 30 and passes through the second waveguide 40. (See Figure 1.)

[0059] (calculation section) The calculation unit 60 evaluates the state of the filament F based on the fluctuation of the electromagnetic wave in the cavity resonator 30. The calculation unit 60 is configured with a calculation device that calculates the location of the electromagnetic wave received by the receiver 50. The state of the filament F can be evaluated based on the variation in the intensity of a certain resonant frequency, or The condition of the filament F can be evaluated based on the fluctuation in the frequency of the generated electromagnetic waves. In this embodiment, the inspection device 1 generates a standing wave of an electromagnetic wave having a predetermined resonant frequency in space. An electromagnetic wave is generated in the cavity 32 of the cavity resonator 30, and the electromagnetic wave is guided from the cavity 32 to a receiver 50. The degree of fluctuation of the electromagnetic wave received by the receiver 50, for example, the resonant frequency, is calculated by the calculation unit. The object of the test is determined based on the degree of variation in at least one of the frequency and amplitude of the The filament F is evaluated for the presence or absence of foreign bodies.

[0060] (Use of chirp waves) Here, the inspection device 1 employs a chirp wave as the electromagnetic wave generated by the oscillator 10. This makes it possible to reduce the signal processing time when using electromagnetic waves in a high frequency band such as the millimeter wave band. This allows the frequency to be down-converted, reducing loss in the signal processing circuitry. It is possible to reduce the amount of data and compress it to a level where it is easy to perform A / D conversion. In the inspection device 1 having the above configuration, chirps with different time change rates are An example of a spectrum measurement method using the difference in waves will be described below (see Figs. 10 to 12). A chirp wave is a waveform based on a signal whose frequency changes over time (a chirp signal). In this embodiment, two frequencies that increase with time are Chirp wave 1 and chirp wave 2 are used.

[0061] In this embodiment, in addition to the oscillator 10, another oscillator 12 is prepared. Chirp wave 1 is emitted from one oscillator and chirp wave 2 is emitted from another oscillator 12 (see FIG. 11). For wave 2, a chirp wave with a different degree of frequency fluctuation from chirp wave 1 is used. The wave 1 is introduced into the cavity resonator 30, and is affected by the resonator. If there is a foreign object M, the foreign object M is detected. After the intensity is changed by the cavity resonance, the chirp wave 2 is output from the output port 33. The cavity resonator 30 is not influenced by the object to be detected. It is added to the chirp wave 1 derived from 30 and used for multiplication.

[0062] These chirp waves 1 and 2 are configured so that their frequencies at a certain point in time are different. (However, the chirp wave 1 and the chirp wave 2 in the graph showing the relationship between time and frequency are In this embodiment, chirp wave 1 and chirp wave 2 are The initial frequency at the start of oscillation and the rate of increase in frequency (in the graph shown in Figure 10(B)) More specifically, in this embodiment, In this case, the initial frequency of chirp wave 1 at the start of oscillation is larger than that of chirp wave 2. In addition, the rate of increase in frequency over time for chirp wave 1 is set to chirp. It is designed to be smaller compared to wave 2.

[0063] Chirp wave 1 and chirp wave 2 have a constant signal strength within the range of the emitted frequency. In other words, the intensity information of the chirp wave 2 does not need to be used. In this embodiment, the frequency information of the chirp wave 2 is down-converted to the frequency of the chirp wave 1. According to this method, the light is converted into a signal immediately after it is output from the cavity resonator 30. It becomes possible to measure the intensity (power) of chirp wave 1 at the stage with greater accuracy. .

[0064] An example will be described further. The chirp wave 1 passing through the cavity resonator 30 starts from t=0. From t=100, the frequency is changed from 77.005GHz to 91.001GHz. Also, the chirp wave 2 that does not pass through the cavity resonator 30 is changed from t=0 to t= Suppose the frequency is changed from 77 GHz to 91 GHz between 100 and 77 GHz (Figure 1). 2(A)). In this case, the change in the frequency difference between the two chirp waves is as shown in the figure. (See Figure 12(B)). The difference at t=0 was 0.005GHz (5MHz). However, at t=100, the difference became 0.001GHz (1MHz). become.

[0065] Here, the frequency difference (IF frequency) is on the horizontal axis, and the intensity of the chirp wave emitted from oscillator 1 ( Or, the intensity of chirp wave 1 emitted from transmitter 1 and the intensity of chirp wave 2 emitted from transmitter 2 The difference in frequency is Fourier transformed to obtain the intensity (not shown). Obtain a spectrum and obtain the relationship between the frequency difference (IF frequency) and the intensity of chirp wave 1. (See FIG. 13(A)) and the frequency that varies with the elapsed time, i.e., the frequency that corresponds to the elapsed time. The difference in the number of chirp waves is plotted on the horizontal axis, and the chirp wave passing through the cavity resonator 30 (i.e., chirp wave 1) Next, based on the above, we will obtain a graph with the intensity of the chirp wave as the vertical axis. If we take the relationship between the original frequency of 1 and the intensity of chirp wave 1 (see Figure 13(B)), this transformation In this case, the frequency can be set lower than the original frequency. It is possible to down-convert the received electromagnetic waves to a frequency band that is easy to convert into analog-to-digital. In the present disclosure, a millimeter wave, which is an electromagnetic wave in a high frequency band, is used. When processing the electromagnetic waves received by a receiver, transmission loss occurs in the electrical circuits that handle the calculations. In particular, the transmission loss due to dielectric loss, which is proportional to the frequency, becomes large. To solve this problem, It will be necessary to change the materials of the electrical circuits, especially the materials of the boards, but currently, millimeter-wave electromagnetic waves There are no materials that can reduce the dielectric loss significantly when using On the other hand, as mentioned above, by performing arithmetic processing on the down-converted electromagnetic wave, It is possible to perform calculations while reducing transmission loss. When implementing a spectrum measurement method using the chirp wave 1, the calculation unit 60 Based on the difference in frequency or signal strength with the chirp wave 2, the presence or absence of abnormality in the filament F is evaluated. Worth it.

[0066] According to the inspection device 1 of the present embodiment as described above, By generating electromagnetic waves such as millimeter waves and making them enter the cavity resonator 30, it is possible to obtain a high-quality image that is not possible with conventional inspection devices. It detects foreign particles M smaller than the several hundred microns that were previously detectable by the In addition, an inspection method in which an electromagnetic wave is irradiated onto the filament F to be inspected in the cavity resonator 30 can be used. When electromagnetic waves (millimeter waves) having a frequency of 30 GHz or more are applied to the device 1, in this embodiment The reason why the inspection device 1 is not merely a device that uses an oscillator 10 suitable for the device is that This is clear from the above description and from the description of the embodiments described below.

[0067] The above-described embodiment is an example of a preferred embodiment of the present invention, but is not intended to be limiting. Various modifications can be made without departing from the spirit and scope of the present invention. In the above embodiment, the inspection device 1 including a single cavity resonator 30 has been described. The filament F includes two or more of the plurality of cavity resonators 30. An inspection system may be configured so that the light passes through the communication passage 35 of the cavity resonator 30. EXAMPLES

[0068] We attempted to verify the principle of anomaly detection using an actual sample of the inspection device 1. The specifications, including the method and resonant frequency, are summarized in Table 1. Here, the filament F is a glass filament. The glass fiber was passed through the communication passage 35 of the cavity resonator 30 and rotated at 5.0 m / min. The electromagnetic waves measured by the receiver 50 when they were passed through the glass fiber at a speed of . Figure 14 shows the state when a normal part of a glass fiber filament F containing no foreign matter passes through. The waveforms shown are the waveforms when an abnormal part of a glass fiber containing a foreign object passes through it. As shown in Figure 14, when the normal part passes, the frequency is around 79 GHz as mentioned above. On the other hand, the abnormal part including the foreign object is located at the cavity resonator 30. When passing through the passage 35, the peak frequency of the resonance frequency and its intensity change. According to the inspection device 1 of the present embodiment as described above, the normal portion (normal portion) of the filament F is (regular part), abnormal part containing foreign matter (metal part 1) In both cases, the peak frequency and intensity changed significantly, and the changes were greater than the measurement error. It was recognized that: [Table 1] In addition, the inspection device 1 in the present disclosure (wherein the diameter of the communication port is Φ: 1.0 mm, In the case of a squirrel diameter of φ0.7 mm, a foreign object with a diameter of α: 0.2 μm and a length of 100 μm (metal ball φ2 It was found that it was possible to detect a volume equivalent to 0.6 μm (see Figure 15). EXAMPLES

[0069] Using an electromagnetic field simulator, we attempted to verify the principle of anomaly detection. Here, the resonant frequency The cavity resonator 30 is designed so that the frequency is between 76 and 81 GHz (wherein the diameter of the communication port Φ : 1.5 mm, iris diameter φ0.6 mm), a filament F containing a foreign object (metal part) M is The foreign object M is passed through the passage 35 (see FIG. 16). As a result of calculation, when the foreign object M enters the cavity resonator 30, It was found that the peak shape, peak intensity, and resonance frequency all changed significantly. (See FIG. 17.) Although the conditions in FIG. 17 are the same as those in FIG. 14, The reason why the peak positions are slightly different is that in reality, the thermal expansion of the metal parts of the cavity resonator 30 and The influence of the tightening method of the screws at the connection between the cavity resonator 30 and the waveguides 20 and 40 is sensitively reflected. It was thought that this was because [Industrial Applicability]

[0070] The present invention is suitable for application to a filament inspection device and inspection system. [Explanation of symbols]

[0071] 1. Inspection equipment 10...Oscillator 12…Another oscillator 20...First waveguide 30...Cavity resonator 31...Entrance 32...Cavity part 33... Outlet 34…Communication port 35…Communication path 36...Protection tube 39…Housing 39a…Top surface 40…Second waveguide 50…Receiver 60...Arithmetic section F: filamentous body M...Foreign object

Claims

1. An apparatus for inspecting a filament, comprising: An oscillator that emits electromagnetic waves with a frequency of 30 GHz or more; a first waveguide having one end connected to the oscillator and forming a waveguide for the electromagnetic wave; an inlet port to which the other end of the first waveguide is connected and through which the electromagnetic wave is introduced; a cavity that resonates in a certain vibration mode; an outlet through which electromagnetic waves are guided from the cavity; a cavity resonator having a communication port forming a communication passage through which a body passes; a second waveguide having one end connected to the outlet and configured to guide the electromagnetic wave from the cavity resonator; and, a receiver for receiving an electromagnetic wave guided from the cavity resonator; A calculation for evaluating a state of the filament based on the fluctuation of the electromagnetic wave in the cavity resonator. Department and An inspection device comprising:

2. Inside the cavity resonator, one or more standing waves are generated from the inlet to the outlet of the cavity. The inspection device according to claim 1 , wherein antinodes are generated.

3. The cavity resonator is characterized in that the number of loops n of a standing wave generated inside the cavity is an odd number.

3. The inspection apparatus according to claim 2.

4. The cavity resonator is characterized in that the number n of loops of a standing wave generated inside the cavity is 3 or more. Item 3. The inspection device according to item 3.

5. The communication passage is configured such that the filament is axially connected to an antinode of a standing wave generated inside the cavity in the vibration mode. The inspection device according to claim 1 , wherein the inspection device is formed to pass through a predetermined range from .

6. The cavity resonator according to claim 1 , wherein the cavity has a rectangular parallelepiped cavity. Inspection equipment.

7. 7. The optical fiber according to claim 1, wherein the inlet and the outlet are formed by an iris.

3. The inspection device according to claim 1 .

8. The method according to any one of claims 1 to 7, wherein the inner surface of the cavity is made of a metal. Inspection equipment.

9. The cavity resonator is provided with a plurality of communication passages for passing a plurality of filaments.

9. An inspection device according to claim 1.

10. Each of the plurality of communication paths is connected to an antinode of a standing wave generated inside the hollow portion by the filament.

9. The method according to claim 8, wherein the first and second electrodes are provided at predetermined intervals so as to pass through a region in a predetermined range from the first to the second. The inspection device described.

11. The calculation unit calculates a fluctuation in intensity of a predetermined resonant frequency included in the electromagnetic wave, and and / or a change in the frequency of wave generation.

11. An inspection device according to claim 1 .

12. The oscillator generates a continuous wave having a first range of frequencies centered around a predetermined resonant frequency. The inspection apparatus according to claim 1 ,

13. 11. The oscillator generates a chirp wave having a series of resonant frequencies.

13. The inspection apparatus according to claim 12 .

14. The calculation unit is configured to calculate the frequency of the signal emitted by the oscillator and received by the receiver via the cavity resonator. The first chirp wave and the chirp wave generated by the oscillator have a frequency fluctuation degree according to time. At least one of the difference in frequency between the first chirp wave and the second chirp wave having a different phase and the difference in signal strength. The presence or absence of an abnormality in the filamentous body is evaluated based on either one of claims 1 to 11 and claim 11. Item 14. The inspection device according to any one of items 13 to 14.

15. A cavity resonator is provided inside the cavity resonator, and the cavity resonator is divided into a communication passage and a cavity portion inside the cavity resonator.

15. The inspection device according to claim 1, further comprising a protective tube defining a space between the first and second electrodes.

16. The communication port is a frequency measuring range defined by the cutoff frequency of the waveguide.

16. The electromagnetic wave having a number is set to a size that does not leak from the cavity.

13. The inspection apparatus according to claim 12 .

17. The inner diameter of the inlet and the inner diameter of the outlet are determined by a line segment connecting the inlet and the outlet. less than 15% of the cross-sectional area of ​​the cavity provided in the cavity resonator in the vertical direction; 17. An inspection device according to any one of claims 1 to 16.

18. A plurality of cavity resonators according to any one of claims 1 to 17, The filament passes through communication passages of two or more of the plurality of cavity resonators. It is configured as follows: Inspection system.

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