JP2019138649A - Flaw detector - Google Patents

Abstract

To heat and image a wide area around the periphery of a subject.SOLUTION: A flaw detector 10 includes a reflector 11 having a mirror surface 11b formed inside in the shape of a truncated conical surface, an infrared camera 12 which images the mirror surface 11b, and a light heater 14 which radiates heating light toward the mirror surface 11b. A subject 2 is disposed inside the mirror surface 11b and on a central axis 11e of the truncated conical surface. The infrared camera 12 images the subject 2 via the mirror surface 11b.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flaw detection apparatus for flaw detection of a subject by taking an image representing a temperature distribution on the surface of the subject.

  As a method for nondestructively detecting a defect existing inside a subject, there is a thermography method (see, for example, Patent Documents 1 and 2). The thermography method is a method for detecting a defect by analyzing an image representing a temperature distribution on the surface of an object. In the thermographic method, a temperature distribution image is acquired by heating a subject and capturing infrared rays emitted from the surface of the subject with an infrared camera. Light emitted from the light heater is used for heating the subject.

Japanese Patent Laid-Open No. 2006-99296 Japanese Patent Laid-Open No. 2006-156733

  By the way, in order to reduce the flaw detection time and the number of flaw detections, it is desired to widen the range in which the subject is imaged by the infrared camera.

  Therefore, the present invention has been made in view of the above circumstances. The problem to be solved by the present invention is to image a subject in the widest possible range with an infrared camera.

  In order to solve the above-described problems, the flaw detection apparatus includes a reflector having a mirror surface formed in the shape of a truncated conical surface, an infrared camera that images the mirror surface, and a heater that heats the subject. The subject is disposed on the inner side of the mirror surface and on the central axis of the truncated conical surface, and the infrared camera images the subject through the mirror surface.

  Since the subject is disposed inside the truncated conical mirror surface and on the central axis of the truncated conical surface, the infrared camera images a wide range of the outer periphery of the subject. Therefore, the flaw detection time and the number of flaw detections can be reduced.

  According to the present invention, it is possible to image a wide range of the outer periphery of the subject.

It is sectional drawing of the flaw detection apparatus of 1st Embodiment. It is sectional drawing of the flaw detection apparatus of 2nd Embodiment. It is sectional drawing of the flaw detection apparatus of 3rd Embodiment. It is sectional drawing of the flaw detection apparatus of 4th Embodiment. It is sectional drawing of the flaw detection apparatus of 5th Embodiment. It is sectional drawing of the flaw detection apparatus of 6th Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below are given various technically preferable limitations for carrying out the present invention. The scope of the present invention is not limited to the following embodiments and illustrated examples.

[First Embodiment]
FIG. 1 is a schematic cross-sectional view of a flaw detection apparatus 10 according to the first embodiment.
The flaw detection apparatus 10 includes a reflector 11, an infrared camera 12, a heating light emitter 13, and a computer 19.

  The reflector 11 is formed in the shape of a truncated cone surface. The reflector 11 has a truncated cone-shaped internal space 11a, and the internal space 11a opens at the bottom and top of the truncated cone. Hereinafter, the bottom opening 11c is referred to as an insertion opening 11c, and the top opening 11d is referred to as a light passage opening 11d.

  A mirror surface 11 b is formed on the inner surface of the reflector 11. The mirror surface 11b is formed into a truncated conical surface as a surface of revolution around the central axis 11e. The apex angle of the frustoconical surface is 90 °, but is not limited thereto.

  The reflector 11 is made of a silver-white metallic material such as aluminum, and the mirror surface 11b has metallic gloss. The mirror surface 11b is a reflecting surface that reflects light. The metallic glossy mirror surface 11b may be formed by forming a silver-white metallic material film on the inner surface of the reflector 11 by vapor deposition, sputtering or plating.

  The subject 2 is inserted into the insertion port 11c and is held on the center line of the reflector 11 by a holder or the like. A part of the subject 2 is disposed in the internal space 11a and is surrounded by a mirror surface 11b. It is preferable that the subject 2 does not protrude from the light passage port 11d to the outside of the internal space 11a. The subject 2 is, for example, a bolt, a screw, a nut, a shaft, a pin, a link, a rivet, a tube, or a piston.

  The subject 2 is arranged on the central axis 11e. Preferably, the subject 2 and the mirror surface 11b are arranged coaxially.

  An infrared camera 12 is disposed at the tip of the light passage port 11 d of the reflector 11. The infrared camera 12 is an infrared camera, and the sensing wavelength band of the infrared camera 12 is an infrared band. For example, the infrared camera 12 senses a far infrared ray having a wavelength band of 8 to 14 μm or a mid-infrared band of 2 to 5 μm.

The infrared camera 12 is directed to the light passage port 11d and the mirror surface 11b of the reflector 11. The infrared camera 12 captures an infrared image of the subject 2 reflected on the mirror surface 11b. The optical axis 12a of the infrared camera 12 and the central axis 11e of the mirror surface 11b are arranged coaxially. Since the mirror surface 11 b is formed in a truncated conical surface, the infrared camera 12 captures an infrared image of the subject 2 reflected on the mirror surface 11 b over the entire outer peripheral surface of the subject 2. Although the shape of the outer peripheral surface of the subject 2 is not particularly limited, for example, it is a cylindrical surface or a polygonal column surface.
The optical axis 12a of the infrared camera 12 may be shifted from the central axis 11e of the mirror surface 11b. Further, the optical axis 12a of the infrared camera 12 may be inclined with respect to the central axis 11e of the mirror surface 11b.

  The infrared camera 12 includes an area-type infrared imaging device, an optical lens that forms an infrared image of the subject 2 reflected on the mirror surface 11b on the infrared imaging device, and an infrared image of the subject 2 photoelectrically converted by the infrared imaging device. An image processing unit for converting the image into a digital image.

  The infrared image of the subject 2 captured by the infrared camera 12 is a digital image, and the infrared camera 12 outputs the digital image to the computer 19. Since the infrared camera 12 periodically captures images with a short period, digital images are sequentially output to the computer 19. The digital image output from the infrared camera 12 to the computer 19 is a thermographic image representing a temperature distribution. Note that a digital image acquired by the infrared camera 12 may be transferred to the display as a video signal, and the digital video may be displayed on the display.

  The computer 19 performs an analysis process on the digital image input from the infrared camera 12. For example, the computer 19 executes a function analysis process that Fourier-transforms the temporal change of the gradation value of each pixel of the digital image input from the infrared camera 12. Since the digital image is a thermographic image representing a temperature distribution, the gradation value of each pixel represents the temperature.

  A light emitting device 13 for heating is disposed at the tip of the light passage port 11 d of the reflector 11. The heating light emitter 13 is directed to the light passage port 11 d and the mirror surface 11 b of the reflector 11. The heating light emitter 13 emits the heating light toward the mirror surface 11b. The wavelength band of the heating light is shorter than the sensing wavelength band of the infrared camera 12. The wavelength band of the heating light is not particularly limited, and is, for example, a visible light band, an ultraviolet band, a near infrared band, or an infrared band. The wavelength band of the heating light may include two or more bands among an ultraviolet band, a visible light band, a near infrared band, and a mid infrared band.

  The heating light emitted from the heating light emitter 13 is reflected by the mirror surface 11 b and enters the surface of the subject 2. Further, part of the heating light emitted from the heating light emitter 13 is directly incident on the surface of the subject 2. The subject 2 is heated by these reflected light and direct light, and infrared rays are emitted from the surface of the subject 2. The higher the temperature of the surface of the subject 2, the higher the energy of infrared rays emitted from the surface of the subject 2. If there is a defect such as peeling, cracking, cracking, or void in the specimen 2, the thermal conductivity of the portion is low. As a result, the surface temperature of the specimen 2 is uneven or the rate of time change of the surface temperature is not good. It becomes even.

  Infrared light emitted from the surface of the subject 2 is reflected by the mirror surface 11 b and enters the infrared camera 12. Thereby, an infrared image of the subject 2 is captured by the infrared camera 12.

The heating light emitter 13 has a plurality of light heaters 14. These light heaters 14 are arranged in the circumferential direction with respect to the optical axis 12 a of the infrared camera 12 and the central axis 11 e of the mirror surface 11 b outside the visual field of the infrared camera 12. These light heaters 14 are preferably arranged at equal intervals. In addition, when the number of the light heaters 14 is 2, the light source 14a of one light heater 14 is symmetrically arranged with respect to the central axis 11e of the mirror surface 11b with respect to the light source 14a of the other light heater 14. It is preferable.
These light heaters 14 are directed to the light passage port 11d and the mirror surface 11b of the reflector 11.
In addition, when the number of the light heaters 14 is 2, one light heater 14 is symmetrically arranged with respect to the center axis 11e of the mirror surface 11b with respect to the other light heater 14.

  Each light heater 14 includes a light source 14a and a reflector 14b. The reflector 14b is, for example, a parabolic reflector. A light source 14a is disposed at the focal point of the reflector 14b. The reflector 14 b is directed to the light passage port 11 d and the mirror surface 11 b of the reflector 11, and the central axis 14 c of the reflector 14 b passes through the internal space 11 a of the reflector 11. Since the light source 14a is disposed at the focal point of the reflector 14b, the central axis 14c of the reflector 14b is also the optical axis of the light heater 14. The light source 14a is, for example, a filament type lamp, a discharge tube type lamp, or a semiconductor light emitting element. More specifically, the light source 14a is a halogen lamp as a filament lamp, a xenon lamp as a discharge tube lamp, a light emitting diode as a semiconductor light emitting element, or a semiconductor laser diode as a semiconductor light emitting element.

  In the example shown in FIG. 1, the central axis 14 c of the reflector 14 b obliquely intersects the optical axis 12 a of the infrared camera 12 and the central axis 11 e of the mirror surface 11 b. Not limited to this, the central axis 14c of the reflector 14b may be parallel to the optical axis 12a of the infrared camera 12 and the central axis 11e of the mirror surface 11b. In this case, the central axis 14 c of the reflector 14 b intersects the mirror surface 11 b of the reflector 11.

Next, the operation and usage method of the flaw detection apparatus 10 will be described.
First, the light source 14a is turned on. The heating light emitted by the light source 14a is reflected by the reflector 14b toward the mirror surface 11b. The heating light reflected by the reflector 14 b is reflected by the mirror surface 11 b and enters the surface of the subject 2. Thereby, the subject 2 is heated.

  Since the heating light emitter 13 is directed to the mirror surface 11 b of the reflector 11, the heating light is irradiated to a wide range of the surface of the subject 2.

Next, the light source 14a is turned off.
Next, when the imaging process of the infrared camera 12 is performed, an infrared image of the subject 2 reflected on the mirror surface 11 b is captured by the infrared camera 12. As the surface temperature of the subject 2 changes, the amount of infrared radiation on the surface of the subject 2 also changes. The rate of change of the surface temperature of the subject 2 is affected by the presence or absence of defects below the surface. Therefore, a defect can be detected based on a change in the digital image captured by the infrared camera 12. The imaging process of the infrared camera 12 may be performed during the lighting period of the light source 14a.
Next, the computer 19 is caused to execute analysis processing of the digital image transferred from the infrared camera 12 to the computer 19.

  In the present embodiment, the subject 2 is disposed in the internal space 11 a of the truncated conical reflector 11, and the infrared camera 12 is directed toward the mirror surface 11 b of the reflector 11. Therefore, a wide range of the surface of the subject 2 is imaged by the infrared camera 12. In particular, since the optical axis 12a of the infrared camera 12 and the central axis 11e of the mirror surface 11b are coaxially arranged, the infrared image of the subject 2 reflected on the mirror surface 11b over the entire circumference of the subject 2 is the infrared camera 12. Is imaged. Therefore, the flaw detection time and the number of flaw detections can be reduced.

  Since the apex angle of the mirror surface 11b is 90 °, the length of the trajectory of the light beam from the portion close to the infrared camera 12 in the subject 2 to the infrared camera 12 via the mirror surface 11b is It is almost equal to the length of the ray trajectory from the part far from the infrared camera 12 to the infrared camera 12 via the mirror surface 11b. Therefore, the infrared camera 12 is focused on the entire subject 2.

  The light source 14a may be a straight tube lamp. In this case, the longitudinal direction of the light source 14a is a direction parallel to the radial direction with respect to the central axis 11e of the mirror surface 11b, and the reflector 14b is, for example, a parabolic reflector, and the light source 14a is a parabolic column. It is arranged at the focal line of the surface. The reflector 14 b is directed to the light passage port 11 d and the mirror surface 11 b of the reflector 11, and the center surface of the reflector 14 b intersects the mirror surface 11 b of the reflector 11. The shape of the reflector 14b may be other shapes, for example, a semi-cylindrical surface type.

  The light source 14a may be a ring-type lamp that surrounds the central axis 11e of the mirror surface 11b. In this case, the reflector 14b is a ring type, and the shape of the reflector 14b on the cut surface passing through the central axis 11e of the mirror surface 11b is a parabolic shape.

[Second Embodiment]
FIG. 2 is a schematic sectional view of a flaw detection apparatus 10A according to the second embodiment.
In the following description, the difference between the flaw detection apparatus 10A of the second embodiment and the flaw detection apparatus 10 of the first embodiment will be described. In addition, components corresponding to each other between the flaw detection apparatus 10A and the flaw detection apparatus 10 are denoted by the same reference numerals.

  The heating light emitter 13 has a single light heater 14, and this light heater 14 faces the reflector 11. That is, the optical axis of the optical heater 14, that is, the central axis 14c of the reflector 14b and the central axis 11e of the mirror surface 11b are arranged coaxially. The central axis 14c of the reflector 14b may be displaced from the central axis 11e of the mirror surface 11b. Further, the heating light emitter 13 may include a plurality of light heaters 14, similarly to the heating light emitter 13 in the first embodiment.

  A dichroic mirror 15 is disposed between the light heater 14 and the mirror surface 11b so as to cross the central axis 14c of the reflector 14b and the central axis 11e of the mirror surface 11b. The angle formed by the central axis 14c of the reflector 14b and the central axis 11e of the mirror surface 11b and the normal line of the dichroic mirror 15 is 45 °. The dichroic mirror 15 reflects light in the sensing wavelength band of the infrared camera 12, that is, light in the infrared band, and transmits light in other bands (particularly, light irradiated by the light heater 14).

  The infrared camera 12 is arranged on the outer side in the radial direction with respect to the central axis 11e of the mirror surface 11b than the dichroic mirror 15. The infrared camera 12 is directed to the dichroic mirror 15, and the optical axis 12 a of the infrared camera 12 is bent by 90 ° by the dichroic mirror 15. The optical axis 12 a of the infrared camera 12 from the infrared camera 12 to the dichroic mirror 15 intersects the intersection of the central axis 11 e of the mirror surface 11 b and the dichroic mirror 15. The optical axis 12a of the infrared camera 12 from the dichroic mirror 15 to the reflector 11 and the central axis 11e of the mirror surface 11b are arranged coaxially.

  Heating light emitted from the light heater 14 passes through the dichroic mirror 15. The heating light transmitted through the dichroic mirror 15 is reflected by the mirror surface 11 b and enters the surface of the subject 2. A part of the heating light transmitted through the dichroic mirror 15 is directly incident on the surface of the subject 2. As a result, the subject 2 is heated and infrared rays are emitted from the surface of the subject 2. As the surface temperature of the subject 2 changes, the amount of infrared radiation on the surface of the subject 2 also changes.

  Infrared rays emitted from the surface of the subject 2 are reflected by the mirror surface 11 b and further reflected by the dichroic mirror 15. The reflected infrared light enters the infrared camera 12. Thereby, an infrared image of the subject 2 is captured by the infrared camera 12.

  As described above, since the dichroic mirror 15 is provided, in the region between the dichroic mirror 15 and the reflector 11, the optical axis 12a of the infrared camera 12, the central axis 11e of the mirror surface 11b, and the optical axis of the optical heater 14 are used. Are arranged coaxially. Therefore, even with a single light heater 14, the surface of the subject 2 can be heated uniformly over the entire circumference, and the subject reflected on the mirror surface 11b over the entire circumference of the subject 2 Two infrared images can be captured by the infrared camera 12.

  Note that the position of the light heater 14 and the position of the infrared camera 12 are interchanged, and the dichroic mirror 15 reflects the heating light emitted by the light heater 14 and transmits light in a band other than the heating light band. Also good. In this case, as in the case of the infrared camera 12 in the first embodiment, the infrared camera 12 is directed to the light passage port 11d and the mirror surface 11b of the reflector 11, and the optical axis 12a of the infrared camera 12 and the central axis 11e of the mirror surface 11b are It is arranged coaxially. Moreover, the light heater 14 is arrange | positioned rather than the dichroic mirror 15 in the radial direction outer side regarding the central axis 11e of the mirror surface 11b. The light heater 14 is directed to the dichroic mirror 15, and the optical axis of the light heater 14 is bent at 90 ° by the dichroic mirror 15.

  Further, the light source 14a may be a straight tube lamp. In this case, the longitudinal direction of the light source 14a is a direction orthogonal to the central axis 11e of the mirror surface 11b. Further, the reflector 14b is, for example, a parabolic column type reflector, and the light source 14a is disposed at the focal line of the parabolic column surface. Further, the reflector 14b is directed to the light passage port 11d and the mirror surface 11b of the reflector 11, and the central surface of the reflector 14b passes through the central axis 11e of the mirror surface 11b of the reflector 11.

  The light source 14a may be a ring-type lamp that surrounds the central axis 11e of the mirror surface 11b. In this case, the reflector 14b is a ring type, and the shape of the reflector 14b on the cut surface passing through the central axis 11e of the mirror surface 11b is a parabolic shape.

  Similarly to the case of the first embodiment, the heating light emitter 13 includes a plurality of light heaters 14, and these light heaters 14 relate to the optical axis 12 a of the infrared camera 12 and the central axis 11 e of the mirror surface 11 b. They may be arranged in the circumferential direction.

[Third Embodiment]
FIG. 3 is a schematic sectional view of a flaw detection apparatus 10B according to the third embodiment.
In the following description, differences between the flaw detection apparatus 10B of the third embodiment and the flaw detection apparatus 10 of the first embodiment will be described. In addition, components corresponding to each other between the flaw detection apparatus 10B and the flaw detection apparatus 10 are denoted by the same reference numerals.

  The subject 2 is a long object, and the length of the subject 2 in the central axis direction is sufficiently longer than the length from the top to the bottom of the truncated conical surface of the reflector 11. The subject 2 is inserted into the insertion port 11c, and the subject 2 and the mirror surface 11b are arranged coaxially.

  The subject 2 is fed in the direction of the central axis 11e of the mirror surface 11b by the feeding device 16, and is rotated around the central axis 11e by the feeding device 16. The feeding device 16 is provided at the tip of the insertion port 11 c of the reflector 11, and the subject 2 is set in the feeding device 16.

  The infrared camera 12 is disposed at the tip of the light passage opening 11d of the reflector 11 so as to face the light passage opening 11d and the mirror surface 11b of the reflector 11. The optical axis 12a of the infrared camera 12 is parallel to the central axis 11e of the mirror surface 11b and is eccentric with respect to the central axis 11e of the mirror surface 11b. The optical axis 12a of the infrared camera 12 intersects the mirror surface 11b. The optical axis 12a of the infrared camera 12 may be slightly inclined with respect to the central axis 11e of the mirror surface 11b.

  The heating light emitter 13 has a single light heater 14. The light heater 14 is disposed at the tip of the light passage opening 11d of the reflector 11 so as to face the light passage opening 11d and the mirror surface 11b of the reflector 11. The optical axis of the light heater 14, that is, the central axis 14c of the reflector 14b is parallel to the central axis 11e of the mirror surface 11b and is eccentric with respect to the central axis 11e of the mirror surface 11b. The optical axis of the light heater 14 may be slightly inclined with respect to the central axis 11e of the mirror surface 11b. Further, the heating light emitter 13 may include a plurality of light heaters 14, similarly to the heating light emitter 13 in the first embodiment.

The light heater 14 and the infrared camera 12 are disposed on the same radius with respect to the central axis 11e of the mirror surface 11b. Moreover, the light heater 14 is arrange | positioned rather than the infrared camera 12 at the radial inside regarding the central axis 11e of the mirror surface 11b. In addition, the infrared camera 12 may be arrange | positioned rather than the optical heater 14 at the radial inside regarding the central axis 11e of the mirror surface 11b.
Both the light heater 14 and the infrared camera 12 are arranged on the outer side in the radial direction with respect to the central axis 11e of the mirror surface 11b than the subject 2. Therefore, even if the subject 2 is sent in the direction of the central axis 11 e by the feeding device 16, the subject 2 does not contact the light heater 14 and the infrared camera 12.

Next, the operation and usage method of the flaw detection apparatus 10 will be described.
First, the light source 14a is turned on while the feeding device 16 is stopped. Thereby, the subject 2 is heated.
Next, the light source 14a is turned off.
Next, when the imaging process of the infrared camera 12 is performed, an infrared image of the subject 2 reflected on the mirror surface 11 b is captured by the infrared camera 12. The imaging process of the infrared camera 12 may be performed during the lighting period of the light source 14a.
Next, the computer 19 is caused to execute analysis processing of the digital image transferred from the infrared camera 12 to the computer 19. At this time, the feeding device 16 is operated to feed the subject 2 by a predetermined distance in the direction of the central axis 11e of the mirror surface 11b by the feeding device 16, or the subject 2 is moved by a predetermined angle around the central axis 11e by the feeding device 16. Rotate. Note that both rotation and axial feed of the subject 2 may be performed by the feeding device 16.
Thereafter, the above-described steps are repeated.

  Note that the imaging process of the infrared camera 12 may be performed while the subject 2 is moved by the feeding device 16 while the light source 14a is turned on.

  In the present embodiment, the subject 2 is inserted into the insertion port 11 c, and the infrared camera 12 is directed to the mirror surface 11 b of the reflector 11. Therefore, a wide range of the surface of the subject 2 is imaged by the infrared camera 12. In particular, since the subject 2 is sent in the circumferential direction and the axial direction by the feeding device 16, the entire surface of the subject 2 becomes a flaw detection range by the infrared camera 12.

  In addition, since the light heater 14 and the infrared camera 12 are arranged on the same side with respect to the subject 2, the infrared camera 12 can capture a range irradiated with the heating light by the light heater 14. That is, a portion that is shaded by the subject 2 is included in the imaging range of the infrared camera 12 only slightly.

  The light source 14a may be a straight tube lamp. In this case, the longitudinal direction of the light source 14a is a direction parallel to the radial direction with respect to the central axis 11e of the mirror surface 11b. The reflector 14b is, for example, a parabolic column type reflector, and the light source 14a is disposed at the focal line of the parabolic column surface. The reflector 14 b is directed to the light passage port 11 d and the mirror surface 11 b of the reflector 11, and the center surface of the reflector 14 b intersects the mirror surface 11 b of the reflector 11.

  The feeding device 16 does not rotate the subject 2 around the central axis 11e of the mirror surface 11b, but the revolution drive mechanism revolves the light heater 14 and the infrared camera 12 around the central axis 11e of the mirror surface 11b. It is good.

[Fourth Embodiment]
FIG. 4 is a schematic cross-sectional view of a flaw detection apparatus 10C according to the fourth embodiment.
In the following description, the difference between the flaw detection apparatus 10C of the fourth embodiment and the flaw detection apparatus 10B of the third embodiment will be described. In addition, the same reference numerals are given to components corresponding to each other between the flaw detection apparatus 10C and the flaw detection apparatus 10B.

  In this flaw detection apparatus 10C, a plurality of infrared cameras 12 are arranged in the circumferential direction with respect to the central axis 11e of the mirror surface 11b. When the number of infrared cameras 12 is 2, one infrared camera 12 is symmetrically arranged with respect to the center axis 11e of the mirror surface 11b with respect to the other infrared camera 12.

  Moreover, the some optical heater 14 is arranged in the circumferential direction regarding the central axis 11e of the mirror surface 11b. When the number of the light heaters 14 is 2, one light heater 14 is symmetrically arranged with respect to the center axis 11e of the mirror surface 11b with respect to the other light heater 14.

  The light source 14a may be a straight tube lamp, and the reflector 14b may be a parabolic column type reflector. In this case, the longitudinal direction of the light source 14a is a direction parallel to the radial direction with respect to the central axis 11e of the mirror surface 11b. Furthermore, the light source 14a is arranged at the focal line of the parabolic column surface which is the shape of the reflector 14b. Further, the reflector 14 b is directed to the light passage port 11 d and the mirror surface 11 b of the reflector 11, and the center surface of the reflector 14 b intersects the mirror surface 11 b of the reflector 11. Even when the light source 14a is a straight tube lamp, the number of the light heaters 14 is not particularly limited. When the number of the light heaters 14 is 2, the light source 14a of one light heater 14 is symmetrically arranged with respect to the central axis 11e of the mirror surface 11b with respect to the light source 14a of the other light heater 14. The reflector 14 b is directed to the light passage port 11 d and the mirror surface 11 b of the reflector 11, and the center surface of the reflector 14 b intersects the mirror surface 11 b of the reflector 11.

[Fifth Embodiment]
FIG. 5 is a schematic cross-sectional view of a flaw detection apparatus 10D according to the fifth embodiment.
In the following description, the difference between the flaw detection apparatus 10D of the fifth embodiment and the flaw detection apparatus 10B of the third embodiment will be described. In addition, components corresponding to each other between the flaw detection apparatus 10D and the flaw detection apparatus 10B are denoted by the same reference numerals.

  A dichroic mirror 15 is disposed between the light heater 14 and the mirror surface 11b. The dichroic mirror 15 is disposed outside the subject 2 in the radial direction with respect to the central axis 11e of the mirror surface 11b. Therefore, the subject 2 does not contact the dichroic mirror 15 even when the subject 2 moves in the direction of the central axis 11 e. The angle formed by the central axis 14c of the reflector 14b and the normal line of the dichroic mirror 15 is 45 °. The dichroic mirror 15 reflects light in the sensing wavelength band of the infrared camera 12, that is, light in the infrared band, and transmits light in other bands (particularly, heating light irradiated by the light heater 14).

  The infrared camera 12 is disposed outside the dichroic mirror 15 in the radial direction with respect to the central axis 11e of the mirror surface 11b. The infrared camera 12 is directed to the dichroic mirror 15, and the optical axis 12 a of the infrared camera 12 is bent by 90 ° by the dichroic mirror 15. The optical axis 12a of the infrared camera 12 from the dichroic mirror 15 to the reflector 11 intersects the mirror surface 11b.

  Heating light emitted from the light heater 14 passes through the dichroic mirror 15. The heating light transmitted through the dichroic mirror 15 is reflected by the mirror surface 11 b and enters the surface of the subject 2. A part of the heating light transmitted through the dichroic mirror 15 is directly incident on the surface of the subject 2. As a result, the subject 2 is heated and infrared rays are emitted from the surface of the subject 2. As the surface temperature of the subject 2 changes, the amount of infrared radiation on the surface of the subject 2 also changes.

  Infrared rays emitted from the surface of the subject 2 are reflected by the mirror surface 11 b and further reflected by the dichroic mirror 15. The reflected infrared light enters the infrared camera 12. Thereby, an infrared image of the subject 2 is captured by the infrared camera 12.

  The light source 14a may be a straight tube lamp, and the reflector 14b may be a parabolic column type reflector. In this case, the longitudinal direction of the light source 14a is a direction parallel to the radial direction with respect to the central axis 11e of the mirror surface 11b. The light source 14a is arranged at the focal line of the parabolic column surface which is the shape of the reflector 14b. The reflector 14b is directed to the dichroic mirror 15, the light passage port 11d, and the mirror surface 11b, and the center plane of the reflector 14b intersects the mirror surface 11b.

  Further, the position of the light heater 14 and the position of the infrared camera 12 are interchanged, and the dichroic mirror 15 reflects the heating light irradiated by the light heater 14, and light in other bands (especially, the sensing wavelength of the infrared camera 12). Band light) may be transmitted. In this case, the infrared camera 12 is directed to the light passage port 11d and the mirror surface 11b of the reflector 11 as in the case of the infrared camera 12 in the third embodiment. The optical axis 12a of the infrared camera 12 is parallel to the central axis 11e of the mirror surface 11b and is eccentric with respect to the central axis 11e of the mirror surface 11b. The optical axis 12a of the infrared camera 12 intersects the mirror surface 11b. The light heater 14 is disposed outside the dichroic mirror 15 in the radial direction with respect to the central axis 11e of the mirror surface 11b. The light heater 14 is directed to the dichroic mirror 15, and the optical axis of the light heater 14 is bent at 90 ° by the dichroic mirror 15.

[Sixth Embodiment]
FIG. 6 is a schematic cross-sectional view of a flaw detection apparatus 10E according to the sixth embodiment.
In the description below, the flaw detection apparatus 10E of the sixth embodiment will be described with respect to differences from the flaw detection apparatus 10D of the fifth embodiment. In addition, the same reference numerals are given to components corresponding to each other between the flaw detection apparatus 10E and the flaw detection apparatus 10D.

  In the sixth embodiment, the number of the light heaters 14 is plural. The same applies to the infrared camera 12 and the dichroic mirror 15. Therefore, there are a plurality of groups including the infrared camera 12, the dichroic mirror 15, the infrared camera 12, the light heater 14, and the dichroic mirror 15. These groups are arranged in the circumferential direction with respect to the central axis 11e of the mirror surface 11b.

[Modification]
In the above first to sixth embodiments, the subject 2 is heated when the heating light irradiated by the light heater 14 enters the subject 2. On the other hand, a heater other than light heating may be used to heat the subject 2. Examples of heaters other than light heating are listed below.

(1) A vibrator may be used as a heater. The vibration exciter heats the subject 2 by applying high frequency vibration to the subject 2. The defect is heated by generating frictional heat due to vibration in the defect present in the subject 2. An example of the vibrator is an ultrasonic vibrator that vibrates the subject 2 with ultrasonic waves.

(2) A heater of a fan heater type or a burner type heats the subject 2 by radiating high-temperature hot air or flame to the subject 2.

(3) A resistor heater that abuts on the subject 2 generates heat by electric energy and heats the subject 2.

(4) An induction heating type heater generates a magnetic field and heats the subject 2 by electromagnetic induction. In this case, the subject 2 is a conductor. When the subject 2 is an insulator, a conductor is brought into contact with the subject 2.

(5) A dielectric heating type heater generates a high-frequency electric field around the subject 2 and heats the subject 2 by generating a dielectric loss in the subject 2. In this case, the subject 2 is a dielectric.

2 ... Subject 10, 10A, 10B, 10C, 10D, 10E ... Flaw detector 11 ... Reflector 11b ... Mirror surface 11e ... Central axis 12 ... Infrared camera 12a ... Optical axis of infrared camera 14 ... Optical heater (heater)
15 ... Dichroic mirror

Claims (9)

A reflector with a mirror surface formed in the shape of a truncated conical surface formed on the inner surface;
An infrared camera for imaging the mirror surface;
A heater for heating the subject,
A flaw detection apparatus in which the subject is arranged on the inner side of the mirror surface and on the central axis of the truncated cone surface, and the infrared camera images the subject through the mirror surface. The heater is a light heater that radiates heating light toward the mirror surface,
The flaw detection apparatus according to claim 1, wherein the subject is heated by irradiating the subject with the heating light irradiated by the light heater toward the subject through the reflecting surface. The flaw detection apparatus according to claim 1 or 2, wherein an optical axis of the infrared camera and a central axis of the truncated conical surface are arranged coaxially. A feeding device for feeding the subject in the direction of the central axis of the truncated conical surface;
The flaw detection apparatus according to claim 1 or 2, wherein the infrared camera is disposed on a radially outer side with respect to a central axis of the frustoconical surface than the subject. A dichroic mirror that is disposed between the light heater and the mirror surface, transmits the heating light irradiated by the light heater, and reflects light in a sensing wavelength band of the infrared camera;
The dichroic mirror is inclined with respect to a central axis of the truncated conical surface;
The infrared camera is directed to the dichroic mirror;
The flaw detection apparatus according to claim 2, wherein the infrared camera images the subject through the dichroic mirror and the mirror surface. The optical axis of the infrared camera is bent by the dichroic mirror,
The flaw detection apparatus according to claim 5, wherein the bent optical axis of the infrared camera and the center axis of the truncated conical surface are arranged coaxially. A dichroic mirror that is disposed between the infrared camera and the mirror surface, transmits light in a sensing wavelength band of the infrared camera, and reflects the heating light irradiated by the light heater;
The dichroic mirror is inclined with respect to a central axis of the truncated conical surface;
The light heater is directed to the dichroic mirror;
The flaw detection apparatus according to claim 2, wherein the light heater irradiates the subject with the heating light through the dichroic mirror and the mirror surface. The flaw detection apparatus according to claim 7, wherein an optical axis of the infrared camera and a central axis of the truncated conical surface are arranged coaxially. A feeding device for feeding the subject in the direction of the central axis of the truncated conical surface;
The flaw detection apparatus according to claim 5 or 7, wherein the infrared camera, the light heater, and the dichroic mirror are arranged on the outer side in the radial direction with respect to a central axis of the truncated cone surface than the subject.

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