Film-like foreign object detection device

Abstract

To provide a foreign matter detection device capable of detecting smaller foreign matter.SOLUTION: A foreign matter detection device 1 includes a transmission unit 10 that transmits electromagnetic waves A1, a super-oscillation lens 11 that condenses the electromagnetic waves A1 emitted from the transmission unit 10 to irradiate a film F with the resulting waves, a receiving unit 12 that transmits output waves A2 output from the film F irradiated with the electromagnetic waves A1 by the super-oscillation lens 11, and a determination unit 13 that determines the presence or absence of foreign matter on the basis of the output waves A2 received by the receiving unit 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present application relates to a device for detecting a film-like foreign object. [Background technology]

[0002] Conventional film foreign body detection devices irradiate the film with illumination light and detect scattered light emitted from foreign bodies (see Patent Document 1). In this case, by narrowing the irradiation range of the electromagnetic wave using a general lens, if a foreign body is present in the spot (within the observation field), the detection sensitivity is increased by increasing the signal-to-noise ratio (SN ratio) of the frequency or spectrum of the reflected wave from the foreign body out of the frequency and / or spectrum of the total reflected wave (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5615941 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the range in which the irradiation range of electromagnetic waves such as illumination light can be narrowed is expressed by the diffraction limit, which is determined by the size and focal length of the lens. The lower limit is the wavelength used based on the size of the lens that can be realistically manufactured. In reality, the range in which the irradiation range can be narrowed is limited to approximately the same wavelength as the electromagnetic wave used. Therefore, the smaller the foreign object, the stronger the electromagnetic waves reflected from the surrounding area of ​​the foreign object become compared to the electromagnetic waves reflected from the foreign object itself, making accurate detection of the foreign object more difficult. The required accuracy for detecting foreign objects on film is increasing year by year, creating a demand for foreign object detection devices that can detect even smaller foreign objects on film.

[0005] The present invention has been made in consideration of these points, and its object is to provide a foreign body detection device for film and other membrane-like objects that can narrow the irradiation range of electromagnetic waves to a range smaller than the diffraction limit of conventional lenses, thereby enabling the detection of smaller foreign bodies. [Means for solving the problem]

[0006] As a result of extensive research, the present inventors have found that the above problems can be solved by using superoscillation technology, and have completed the present invention.

[0007] (1) A foreign object detection device for detecting foreign objects on a film-like body, comprising: a transmitter that emits electromagnetic waves; a super-oscillation lens that focuses the electromagnetic waves emitted from the transmitter and irradiates the film-like body; a receiver that receives output waves output from the film-like body irradiated with electromagnetic waves by the super-oscillation lens; and a judgment unit that judges the presence or absence of foreign objects based on the output waves received by the receiver. (2) The foreign matter detection device for a film-like object according to (1), wherein the super oscillation lens forms a linear focused spot across the entire width of the film-like object in the direction of the short side. (3) A foreign object detection device for a film-like body described in (1) or (2), wherein the super-oscillation lens has a plurality of slits arranged in parallel, and the plurality of slits have a width shorter than the wavelength of the electromagnetic wave. (4) A foreign object detection device for a film-like body described in (3), wherein the multiple slits are oriented so that the longitudinal direction of the slits is perpendicular to the long side direction of the elongated film-like body, and are arranged in a row along the long side direction of the film-like body. (5) A foreign object detection device for a film-like body according to (3) or (4), wherein the plurality of slits have a length equal to or greater than the width of the short side of the elongated film-like body. (6) The device for detecting a foreign object in a film-like body according to any one of (1) to (5), wherein the super-oscillation lens has an incident surface and an exit surface for electromagnetic waves that are parallel to each other and has a flat shape. (7) The device for detecting foreign matter in a film-like body according to any one of (1) to (6), wherein the super oscillation lens is disposed so that the exit surface and the surface of the film-like body are parallel to each other. (8) The film-like foreign object detection device according to any one of (1) to (7), wherein a plurality of the receiving sections are arranged. (9) The foreign object detection device for a film-like body according to (8), wherein the plurality of receiving units are arranged in a line along the short side direction of the long film-like body. (10) A foreign object detection device for a membrane-like body described in (8) or (9), wherein at least one of the plurality of receiving units is positioned at a different position from the other receiving units in the direction of the long side of the membrane-like body. (11) The device for detecting a foreign object on a film-like body according to any one of (1) to (10), wherein the determining unit determines the presence or absence of a foreign object based on a change in intensity of the output wave. (12) The device for detecting a foreign object in a film-like body according to any one of (1) to (11), wherein the electromagnetic waves from the transmitter have a frequency of 30 GHz or more and 10 THz or less. (13) A foreign object detection device for a film-like body described in any one of (1) to (12), wherein the super-oscillation lens is configured to be able to irradiate electromagnetic waves onto a plurality of film-like bodies arranged in a line along the direction of irradiation of the electromagnetic waves, and the receiving unit is configured to be able to receive output waves output from the plurality of film-like bodies. (14) A foreign object detection device for a film-like body described in any one of (1) to (13), further comprising a scanning unit that scans an optical system having at least the transmitter and the super-oscillation lens relative to the film-like body. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a film-like foreign object detection device capable of detecting smaller foreign objects. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of the configuration of a foreign object detection device. [Figure 2]FIG. 2 is a schematic diagram of a super oscillation lens of the foreign object detection device as viewed from above. [Figure 3] 1 is a schematic diagram showing electromagnetic waves that pass through a super-oscillation lens of a foreign matter detection device and are irradiated onto a film, and their intensity distribution. [Figure 4] 10A and 10B are explanatory diagrams illustrating the intensity distribution of electromagnetic waves created by the slit arrangement of a super oscillation lens. [Figure 5] FIG. 4 is an explanatory diagram showing an example of an output wave. [Figure 6] FIG. 1 is a schematic diagram showing the configuration of a foreign matter detection device that detects foreign matters on two films. DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the present invention will now be described with reference to the drawings.

[0011] FIG. 1 is a schematic diagram showing an example of the configuration of a foreign object detection device 1 according to this embodiment. The foreign object detection device 1 is for detecting foreign objects that have entered the surface of a detection object F or the interior of the detection object F. The foreign object detection device according to this embodiment is suitable for use when the detection object is a film-like object. Examples of film-like objects to be detected include film, glass cloth, nonwoven fabric, and prepreg. The following description will be given using a film F as an example, but the detection object is not limited to this. The film F is, for example, a long strip made of resin such as PE. The foreign object P is a metal piece or the like.

[0012] The foreign body detection device 1 includes a transmitter 10 that emits electromagnetic waves A1, a super-oscillation lens 11 that collects the electromagnetic waves A1 emitted from the transmitter 10 and irradiates the film F, a receiver 12 that receives an output wave A2 that is generated as a result of being output from the film F to which the electromagnetic waves A1 have been irradiated by the super-oscillation lens 11, a judgment unit 13 that judges the presence or absence of a foreign body P based on the output wave A2 received by the receiver 12, and a scanning unit 14 that scans an optical system having at least the transmitter 10 and the super-oscillation lens 11 relative to the film F.

[0013] The transmitter 10 is an electromagnetic wave transmitter element such as a quantum cascade laser, a Schottky barrier diode, a Gunn diode, or a Tannett diode. The transmitter 10 can emit electromagnetic waves A1 at frequencies between 30 GHz and 10 THz, including so-called millimeter waves and THz waves. More preferably, the electromagnetic waves A1 have frequencies between 100 GHz and 10 THz. The transmitter 10 can emit the electromagnetic waves A1 toward the entire surface of the super-oscillation lens 11. The transmitter 10 preferably has multiple oscillators arranged in the short-side direction (TD direction in FIG. 1) of the film F, which is the target of foreign matter detection. This allows for the generation of high-intensity electromagnetic waves A1, thereby improving foreign matter detection sensitivity. The polarization direction of the transmitter 10 is set parallel to the short-side direction (Y direction in FIG. 1) of the super-oscillation lens 11.

[0014] The super oscillation lens 11 of the present disclosure has a rectangular, flat plate shape, with the electromagnetic wave incident surface 11a and the electromagnetic wave exit surface 11b being parallel to each other. Note that the "flat shape" referred to here means that the overall shape is flat, and also includes surfaces with irregularities. The thickness of the super oscillation lens 11 is not particularly limited as long as it does not interfere with the focusing of the irradiated electromagnetic wave A1. More specifically, it is preferable to set the thickness dimension to less than half the wavelength of the electromagnetic wave A1 to be focused. As an example, when the super oscillation lens 11 focuses an electromagnetic wave A1 of 100 GHz (wavelength of approximately 3 mm), it is preferable that the thickness be less than 1.5 mm, which is half the wavelength. In the present disclosure, the super oscillation lens 11 has a thickness dimension of 400 μm or less.

[0015] The super-oscillation lens 11 of the present disclosure includes a polymer film having a thickness of several hundred micrometers and a metal thin film disposed on the surface of the polymer film. The areas where the metal thin film is not disposed form slits 30, which will be described later. The surface irregularities of the super-oscillation lens 11 are those that do not interfere with the super-oscillation lens 11's ability to focus the electromagnetic wave A1. In the present disclosure, the surface irregularities refer to those that represent the difference in thickness between the areas where the metal thin film is disposed and the areas where the metal thin film is not disposed. For example, such irregularities have a thickness of several hundred nanometers. The metal thin film can be formed by a known method, such as a vapor deposition process. In the present disclosure, the super-oscillation lens 11 has a length that is approximately the same as or longer than the short-side direction (TD direction) of the film F. In other words, the super-oscillation lens 11 is configured so that the entire short-side direction of the film F to be detected is irradiated with the electromagnetic wave A1.

[0016] The super-oscillation lens 11 is positioned so that its exit surface 11b faces the film F. The super-oscillation lens 11 is also positioned a predetermined distance from the film F so that a focused spot S having an intensity equal to or greater than a predetermined value due to the super-oscillation of the electromagnetic wave A1 overlaps with the film F. In this case, the super-oscillation lens 11 is preferably positioned parallel to the horizontal plane of the film F (the MD-TD plane in FIG. 1). This causes specularly reflected light from the film F to be reflected toward the super-oscillation lens 11, thereby preventing the specularly reflected light from entering the detection unit 12 (described later), thereby increasing the detection sensitivity of the detection unit 12. The super-oscillation lens 11 may also be installed tilted at a predetermined angle around the horizontal X-axis. This allows the detection unit 12 to capture backscattered waves from the foreign object being detected.

[0017] The super oscillation lens 11 may be installed so that it rotates a predetermined angle around an axis perpendicular to the vertical plane (the horizontal plane of the film F) and so that the slit 30, which will be described later, is tilted with respect to the short side direction (TD direction) of the film F. This makes it possible to vary the timing at which the scattered waves generated when the focused electromagnetic waves A1 are irradiated onto a foreign object reach the detection unit 12 depending on the location of the foreign object. As a result, it is possible to improve the detection sensitivity for determining where in the TD direction of the film F a foreign object is located.

[0018] The super oscillation lens 11 has a plurality of linear slits 30. The linear slits 30 are regularly arranged in parallel so that the electromagnetic wave A1 forms a focused spot S at a point a predetermined distance away from the emission surface 11b. The slits 30 are formed, for example, by applying a pattern of a thin metal film to the surface of a transparent substrate. As a result, the portions without the thin metal film become the slits 30. The slits 30 have an elongated rectangular shape.

[0019] A super-oscillation lens 11 has multiple linear slits 30 arranged parallel to one another, and forms a focused spot S parallel to the linear slits 30 at a position a predetermined distance from the exit surface 11b of the super-oscillation lens 11. In the present disclosure, the super-oscillation lens 11 is disposed so that the focused spot S occurs at a position where the film F intersects. As a result, the focused spots S formed parallel to the linear slits 30 are continuously formed across the short side direction of the film F. As a result, by transporting the film F in its transport direction (MD direction), the entire film F can be included in the detection range. The super-oscillation lens 11 is disposed so that the focused spot S is formed parallel to the short side direction of the film F. The super-oscillation lens 11 may also be disposed at a predetermined angle with respect to the film F so that the focused spot S is formed at a predetermined angle with respect to the short side direction of the film F.

[0020] The focused spot S is formed so that the range of the focused electromagnetic wave A1 whose intensity is equal to or greater than a predetermined value is equal to or greater than the thickness of the film F. In other words, the focused spot S is formed so as to have a predetermined depth of field in the thickness direction of the film F.

[0021] In the present disclosure, each slit 30 is oriented so that its longitudinal direction X is perpendicular to the long side direction (MD direction) of the long film F. The multiple slits 30 are arranged side by side along the MD direction of the film F.

[0022] 2, the multiple slits 30 have a length in the longitudinal direction X that is equal to or greater than the width in the short side direction (TD direction) of the film F. The multiple slits 30 also have a width D1 in the short side direction Y that is shorter than the wavelength of the electromagnetic wave A1.

[0023] 3, the number, arrangement, and width D1 of the multiple slits 30 are designed to satisfy the conditions for superoscillation, i.e., to form a focused spot S that overlaps with the film F. That is, the multiple slits 30 diffract the electromagnetic wave A1 passing through them to generate multiple spatial frequencies, and the multiple electromagnetic waves generated from the electromagnetic wave A1, which have different spatial frequencies and intensities, interfere with each other. As a result, the intensity distribution at the irradiation position on the film F is designed to have a peak H1 that is thinner than the diffraction limit of a typical lens.

[0024] For example, the multiple slits 30 are designed as follows: First, the minimum width of the slits to be used is determined, and then regions of this minimum width are divided into areas in the direction in which light is to be focused across the entire lens, and the electromagnetic wave transmittance in each region is determined. The initial value is determined randomly, and the intensity distribution at the focal position when using that design is calculated, and the spot diameter is calculated. Angular spectrum methods, etc., are used to calculate the intensity distribution. The spot diameter is used as an evaluation function, and the lens design is optimized so that it is small and the focused electromagnetic wave intensity is strong. Methods such as BPSO (binary particle swarm optimization) are used for this optimization.

[0025] 4, the multiple slits 30 of the super oscillation lens 11 are created so as to overlap multiple slit patterns P1, P2, P6. As a result, the intensity distribution of the electromagnetic wave A1 that passes through each of the slit patterns P1, P2, P6 and is irradiated onto the film F essentially becomes a plurality of waveforms, for example, A, Bcos(x), Ccos(2x), Dcos(3x), Ecos(4x), and Fcos(5x) (A to F are constants). Then, by adding, overlapping, and optimizing these intensity distribution waveforms as shown in the following equation, a waveform that forms a peak H of the intensity distribution of the electromagnetic wave A1 at the focal spot S (center of the lens) on the film F is formed. f(x)=A+Bcos(x)+Ccos(2x)+Dcos(3x)+Ecos(4x)+Fcos(5x)

[0026] As shown in FIG. 1 , the receiving unit 12 is an electromagnetic wave detection element such as a Schottky barrier diode or a pyroelectric element. For example, a plurality of receiving units 12 are arranged. The plurality of receiving units 12 are arranged, for example, on the film F (the side of the film F where the transmitting unit 10 is located), for example, lined up along the TD direction of the film F. The receiving units 12 receive an electromagnetic wave A1 irradiated onto the film F, and receive an output wave A2 (including a reflected wave, a scattered wave, a diffracted wave, etc.) output from the film F in response to the irradiation of the electromagnetic wave A1. Information on the output wave A2 received by the receiving units 12 is output to the determining unit 13.

[0027] The multiple receiving units 12 may be arranged so that their positions are shifted in the MD direction of the film F. In this way, the time at which a change in the intensity of the output wave A2 occurs varies for each receiving unit 12. Therefore, in addition to the change in the intensity of the received output wave A2, foreign matter can be detected by utilizing the change in the received output wave A2 over time.

[0028] Furthermore, when the super-oscillation lens 11 is arranged rotated by a predetermined angle around the vertical axis as described above, the multiple receiving units 12 may be aligned parallel to the longitudinal direction X of the slits 30 formed in the super-oscillation lens 11, in accordance with the rotation angle of the super-oscillation lens 11 around the vertical axis. Also, when the super-oscillation lens 11 is arranged tilted by a predetermined angle around the X-axis, the multiple receiving units 12 may be arranged at appropriate positions depending on the tilt of the super-oscillation lens 11 with respect to the X-axis.

[0029] The receiving section 12 may be provided on the opposite side of the transmitting section 10 and the super-oscillation lens 11, with the film F in between. In this case, it is possible to measure backscattering of foreign matter, and depending on the properties and shape of the foreign matter, the SN ratio may be improved.

[0030] The determination unit 13 is, for example, a computer, and determines the presence or absence of a foreign object P based on a change in the intensity of the output wave A2 obtained from the receiving unit 12. For example, the determination unit 13 determines that a foreign object P is present when the peak intensity of the intensity distribution of the output wave A2 is greater than a threshold value, and determines that a foreign object P is not present when the peak intensity of the intensity distribution of the output wave A2 is less than the threshold value. Note that the determination unit 13 may determine the presence or absence of a foreign object based on information about the output waves A2 of all of the multiple receiving units 12, or may determine the presence or absence of a foreign object based on information about the output waves A2 of some of the receiving units 12.

[0031] The scanning unit 14 is, for example, a transport device that transports the film F in its MD direction. This transport device has, for example, rollers 50 that transport the film F by rotation. The scanning unit 14 moves the film F relative to the super-oscillation lens 11 while facing the super-oscillation lens 11. The transport device may be provided in a film manufacturing apparatus that manufactures the film F, and in this case, foreign matter P is detected during the manufacturing process of the film F.

[0032] Next, the operation of the foreign object detection device 1 will be described. As shown in FIG. 1, first, the film F is transported in the MD direction by the scanning unit 14 while facing the super-oscillation lens 11. As a result, the film F passes below the super-oscillation lens 11 at a constant speed. Then, while the film F is being transported, an electromagnetic wave A1 is emitted from the transmitter 10. The electromagnetic wave A1 passes through the multiple slits 30 in the super-oscillation lens 11, where it is focused and then irradiated onto the film F. At this time, the electromagnetic wave A1 is irradiated onto a linear portion (focused spot S) that is a single point in the MD direction of the film F and spans the entire width of the film F in the TD direction. At this time, the electromagnetic wave A1 is irradiated with an intensity distribution in the MD direction, with a peak H1 that is thinner than the diffraction limit of a general lens, as shown in FIG. 3. The electromagnetic wave A1 has a constant intensity distribution in the TD direction.

[0033] The receiving unit 12 then receives the output wave A2 that is reflected and scattered by the film F and output. For example, in areas where there is no foreign matter on the film F, most of the electromagnetic wave A1 passes through the film F, and in areas where there is a foreign matter on the film F, most of the electromagnetic wave A1 is reflected by the film F. If there is a foreign matter, the receiving unit 12 receives the output wave A2 as shown in FIG. 5. Information about the output wave A2 received by the receiving unit 12 is output to the determining unit 13. For example, if there is a foreign matter, the peak intensity of the output wave A2 will be greater than if there is no foreign matter.

[0034] Next, the determining unit 13 determines that a foreign object is present if the peak intensity of the intensity distribution of the output wave A2 is greater than a threshold value, and determines that a foreign object is not present if the peak intensity is less than the threshold value.

[0035] According to this embodiment, the foreign object detection device 1 comprises a transmitter 10, a super-oscillation lens 11, a receiver 12, and a judgment unit 13, and is therefore able to narrow the irradiation range of the electromagnetic wave A1 to a range smaller than the diffraction limit of conventional lenses, thereby enabling the detection of smaller foreign objects.

[0036] The super oscillation lens 11 forms a linear focused spot S across the entire width of the film F in the direction of the short side, so that foreign matter on the film F can be detected without fail.

[0037] The super oscillation lens 11 has a plurality of slits 30 arranged in parallel, and the plurality of slits 30 have a width D1 that is shorter than the wavelength of the electromagnetic wave A1, which allows the super oscillation lens 11 to suitably collect and irradiate the electromagnetic wave A1.

[0038] The multiple slits 30 are oriented so that the longitudinal direction X of the slits 30 is perpendicular to the long side direction (MD direction) of the film F, and are arranged side by side along the MD direction of the film F. This causes the electromagnetic wave A1 to be focused in the MD direction of the film F and irradiated linearly in the short side direction (TD direction) of the film F. As a result, foreign objects can be detected over a wide area in the TD direction of the film F, and foreign objects in the film F can be detected favorably.

[0039] The multiple slits 30 have a length equal to or greater than the width of the short side direction (TD direction) of the film F, so that the electromagnetic wave A1 is irradiated across the entire width in the TD direction of the film F. This allows for favorable detection of foreign matter in the film F.

[0040] The super oscillation lens 11 has an incident surface 11a and an exit surface 11b for the electromagnetic wave A1 that are parallel to each other and has a flat shape, so that the foreign object detection device 1 can be made smaller and more space-saving.

[0041] Furthermore, when the super oscillation lens 11 is positioned so that the exit surface 11b is parallel to the surface of the film F, the specularly reflected light from the film F is prevented from reflecting toward the lens and entering the detection unit 12, thereby increasing the detection sensitivity of the detection unit 12.

[0042] Since a plurality of receiving sections 12 are arranged, the output wave A2 output from the film F can be received more reliably, and the precision of detecting foreign matter can be improved.

[0043] The multiple receiving units 12 are arranged in a line along the short side direction (TD direction) of the film F, so that foreign matter can be properly detected no matter where in the TD direction of the film F the foreign matter is located.

[0044] In this embodiment, if at least one of the multiple receiving units 12 is disposed at a different position (shifted position) from the other receiving units in the long side direction of the film F, the timing at which the scattered waves generated when the focused electromagnetic waves A1 are irradiated onto the foreign object reach the detecting unit 12 can be made to differ depending on the location of the foreign object. As a result, the detection sensitivity for determining the position of the foreign object in the TD direction of the film F can be improved.

[0045] The determining unit 13 determines the presence or absence of a foreign object based on a change in the intensity of the output wave A2, and therefore can detect the foreign object with high accuracy.

[0046] The electromagnetic waves A1 from the transmitter 10 have a frequency of 30 GHz or more and 10 THz or less, which allows high transparency through the film F. Therefore, the electromagnetic waves A1 can be transmitted through areas without foreign matter and can be reflected or scattered by areas with foreign matter, thereby enabling more accurate detection of foreign matter. Furthermore, foreign matter inside the film F can be properly detected.

[0047] The foreign matter detection device 1 includes a scanning unit 14 that causes an optical system having at least a transmitter 10 and a super oscillation lens 11 to relatively scan the film F. This allows for suitable detection of foreign matters on the entire film F.

[0048] In the above embodiment, the foreign object detection device 1 detects foreign objects on a single film F. However, foreign objects on multiple films may also be detected simultaneously. In such a case, as shown in FIG. 6, for example, the super-oscillation lens 11 may be configured to irradiate electromagnetic waves A1 onto multiple films, for example, two films F1 and F2, arranged side by side along the direction of irradiation of the electromagnetic waves A1 (vertical direction), and the receiving unit 12 may be configured to receive output waves A2 output from the two films F1 and F2. In such a case, a portion of the electromagnetic waves A1 that pass through the super-oscillation lens 11 is irradiated onto the film F1, and a portion of the electromagnetic waves A1 passes through the film F1 and is irradiated onto the film F2. The output waves A2 output from the films F1 and F2 are then received by the receiving unit 12. In this way, the electromagnetic wave A1 that passes through the super oscillation lens 11 is configured so that the depth of field of the focal point is at least equal to or greater than the thickness of the film F, so that it is properly irradiated onto both films F1 and F2 that are aligned in the irradiation direction, and output wave A2 is properly output from films F1 and F2. This makes it possible to properly detect foreign objects on the two films F1 and F2 simultaneously.

[0049] In the above embodiment, the scanning unit 14 transports the film F relative to the optical system, such as the transmitter 10 and the super-oscillation lens 11, but it may also move the optical system, such as the transmitter 10 and the super-oscillation lens 11, over the film F. In such a case, the foreign object detection device 1 is provided with, for example, a moving device that moves the optical system, such as the transmitter 10 and the super-oscillation lens 11, along the MD direction of the film F. The optical system that moves relative to the film F may include the receiver 12 and the judgment unit 13.

[0050] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the ideas described in the claims, and it is understood that these modifications and alterations also fall within the technical scope of the present invention.

[0051] For example, the arrangement, number, width, etc. of the slits 30 of the super oscillation lens 11 are not limited to those in the above embodiment. The type, material, etc. of the film F are also not limited to those in the above embodiment. [Industrial Applicability]

[0052] The present invention is useful in providing a film foreign matter detection device that can detect smaller foreign matters. [Explanation of symbols]

[0053] 1 Foreign object detection device 10. Communications Department 11 Super Oscillation Lens 12 Receiving section 13 Judgment Department 14 Scanning unit 30 slits A1 Electromagnetic waves A2 output wave F film

Claims

1. A foreign object detection device for detecting a film-like foreign object, a transmitter that transmits electromagnetic waves, the electromagnetic waves having a frequency of 30 GHz or more and 10 THz or less; a super-oscillation lens that focuses the electromagnetic waves emitted from the transmitter and irradiates the film-like body, the super-oscillation lens having a plurality of slits arranged in parallel, the plurality of slits having a width shorter than the wavelength of the electromagnetic waves; a receiving unit that receives an output wave output from the film-like body that has been irradiated with an electromagnetic wave by the super oscillation lens; a determination unit that determines whether or not a foreign object is present based on the output wave received by the receiving unit, The film-like body is a long film, A foreign object detection device for a film-like body, wherein each of the multiple slits has an elongated rectangular shape, the longitudinal direction of each slit is oriented in the short side direction of the long film-like body, and the multiple slits are arranged in a regular, parallel pattern in the long side direction of the long film-like body.

2. 2. The device for detecting foreign matter on a film-like object according to claim 1, wherein the super oscillation lens forms a linear focused spot across the entire width of the film-like object in the direction of its short side.

3. 3. The device for detecting foreign matter on a film-like body according to claim 1, wherein the plurality of slits have a length equal to or greater than the width of the long film-like body in the short side direction.

4. 4. The device for detecting foreign matter in a film-like body according to claim 1, wherein the super oscillation lens has an incident surface and an exit surface for electromagnetic waves that are parallel to each other and has a flat shape.

5. 5. The device for detecting foreign matter on a film-like body according to claim 1, wherein the super oscillation lens is disposed so that an exit surface thereof is parallel to the surface of the film-like body.

6. 6. The film-shaped foreign object detection device according to claim 1, wherein a plurality of the receiving sections are arranged.

7. The foreign object detection device for a film-like body according to claim 6 , wherein the plurality of receiving units are arranged in a line along a direction of a short side of the elongated film-like body.

8. 8. The device for detecting foreign matter on a film-like body according to claim 6, wherein at least one of said plurality of receiving sections is arranged at a different position from other receiving sections in the direction of the long side of said film-like body.

9. 9. The device for detecting a foreign object on a film-like body according to claim 1, wherein the determining unit determines the presence or absence of a foreign object based on a change in intensity of the output wave.

10. the super oscillation lens is configured to be able to irradiate electromagnetic waves onto a plurality of film-like bodies arranged in a line along an irradiation direction of the electromagnetic waves, 10. The device for detecting foreign matter on a film-like body according to claim 1, wherein the receiving section is configured to be able to receive output waves output from the plurality of film-like bodies.

11. 11. A foreign object detection device for a film-like body as described in any one of claims 1 to 10, further comprising a scanning unit that scans an optical system having at least the transmitter and the super oscillation lens relative to the film-like body.

Images