JP7041950B2 - Scratch detector - Google Patents

Description

The present invention relates to a flaw detector that detects a subject by capturing an image showing the temperature distribution on the surface of the subject.

As a method for non-destructively detecting defects existing inside a subject, there is a thermography method (see, for example, Patent Documents 1 and 2). The thermography method is a method of detecting defects by analyzing an image showing the temperature distribution on the surface of a subject. 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 by a light heater is used to heat the subject.

Japanese Unexamined Patent Publication No. 2016-9296 Japanese Unexamined Patent Publication No. 2016-156733

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 capture an image of a subject in the widest possible range by an infrared camera.

In order to solve the above problems, the flaw detector includes a reflector with a mirror surface shaped like a conical surface formed on the inner surface, an infrared camera that captures the mirror surface, and a heater that heats the subject. The subject is arranged inside the mirror surface and on the central axis of the cutting conical surface, and the infrared camera captures the subject through the mirror surface.

Since the subject is located inside the conical surface of the crest and on the central axis of the conical surface, the infrared camera captures a wide range of the outer circumference of the subject. Therefore, the flaw detection time and the number of flaw detections can be reduced.

According to the present invention, a wide range of the outer circumference of the subject can be imaged.

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.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiments described below are provided with 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 the flaw detector 10 according to the first embodiment.
The flaw detector 10 includes a reflector 11, an infrared camera 12, a light emitter 13 for heating, and a computer 19.

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

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

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

The subject 2 is inserted into the insertion slot 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 arranged in the internal space 11a and is surrounded by a mirror surface 11b. It is preferable that the subject 2 does not protrude out of the internal space 11a from the light passage port 11d. Subject 2 is, for example, a bolt, screw, nut, shaft, pin, link, rivet, tube or 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 arranged in front of the light passage port 11d 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 far infrared rays in the wavelength band of 8 to 14 μm or mid-infrared bands of 2 to 5 μm.

The infrared camera 12 is directed toward 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 11b is formed in a conical surface shape, the infrared camera 12 captures an infrared image of the subject 2 reflected on the mirror surface 11b over the entire outer peripheral surface of the subject 2. The shape of the outer peripheral surface of the subject 2 is not particularly limited, but is, for example, a cylindrical surface or a polygonal prism surface.
The optical axis 12a of the infrared camera 12 may be deviated from the central axis 11e of the mirror surface 11b. Further, the optical axis 12a of the infrared camera 12 may be tilted with respect to the central axis 11e of the mirror surface 11b.

The infrared camera 12 includes an area-type infrared image pickup element, an optical lens that forms an infrared image of the subject 2 reflected on the mirror surface 11b on the infrared image pickup element, and an infrared image of the subject 2 photoelectrically converted by the infrared image pickup element. It has an image processing unit that converts 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 takes images in a short cycle, 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 showing the temperature distribution. The digital image acquired by the infrared camera 12 may be transferred to the display as a video signal, and the digital image may be displayed on the display.

The computer 19 executes an analysis process of a digital image input from the infrared camera 12. For example, the computer 19 executes a functional analysis process that Fourier transforms the time 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 showing the temperature distribution, the gradation value of each pixel represents the temperature.

A light emitter 13 for heating is arranged at the tip of the light passage port 11d of the reflector 11. The heating light emitter 13 is directed to the light passing port 11d and the mirror surface 11b of the reflector 11. The heating light emitter 13 irradiates 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, but 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 of the ultraviolet band, the visible light band, the near infrared band, and the mid-infrared band.

The heating light emitted from the heating light emitter 13 is reflected by the mirror surface 11b and is incident on the surface of the subject 2. Further, a 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 radiated 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 radiated from the surface of the subject 2. If defects such as peeling, cracks, cracks, and voids are present in the subject 2, the heat conduction of the portion is low, and as a result, the surface temperature of the subject 2 becomes uneven or the rate of change of the surface temperature with time is not high. It becomes uniform.

The infrared rays emitted from the surface of the subject 2 are reflected by the mirror surface 11b and are incident on the infrared camera 12. As a result, the 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 optical heaters 14 are arranged in the circumferential direction with respect to the optical axis 12a of the infrared camera 12 and the central axis 11e of the mirror surface 11b outside the field of view of the infrared camera 12. It is preferable that these light heaters 14 are arranged at equal intervals. When the number of the optical heaters 14 is 2, the light source 14a of one optical heater 14 is symmetrically arranged with respect to the light source 14a of the other optical heater 14 with respect to the central axis 11e of the mirror surface 11b. Is preferable.
These light heaters 14 are directed toward the light passage port 11d and the mirror surface 11b of the reflector 11.
When the number of the optical heaters 14 is 2, one optical heater 14 is symmetrically arranged with respect to the other optical heater 14 with respect to the central axis 11e of the mirror surface 11b.

Each light heater 14 includes a light source 14a and a reflector 14b. The reflector 14b is, for example, a parabolic reflector. The light source 14a is located at the focal point of the reflector 14b. The reflector 14b is directed toward the light passage port 11d and the mirror surface 11b of the reflector 11, and the central axis 14c of the reflector 14b passes through the internal space 11a of the reflector 11. Since the light source 14a is located 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 type lamp, a xenon lamp as a discharge tube type 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 14c of the reflector 14b diagonally intersects the optical axis 12a of the infrared camera 12 and the central axis 11e of the mirror surface 11b. 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 14c of the reflector 14b intersects the mirror surface 11b of the reflector 11.

Subsequently, the operation and usage of the flaw detector 10 will be described.
First, the light source 14a is turned on. The heated light radiated by the light source 14a is reflected by the reflector 14b toward the mirror surface 11b. The heated light reflected by the reflector 14b is reflected by the mirror surface 11b and is incident on the surface of the subject 2. As a result, the subject 2 is heated.

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

Next, the light source 14a is turned off.
Next, when the image pickup process of the infrared camera 12 is performed, the infrared image of the subject 2 reflected on the mirror surface 11b is imaged 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 under the surface. Therefore, defects can be detected based on changes in the digital image captured by the infrared camera 12. The image pickup process of the infrared camera 12 may be performed during the lighting period of the light source 14a.
Next, the computer 19 is made to execute the analysis processing of the digital image transferred from the infrared camera 12 to the computer 19.

In the present embodiment, the subject 2 is arranged in the internal space 11a of the conical surface type reflector 11, and the infrared camera 12 is directed to the mirror surface 11b 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 arranged coaxially, 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. Imaged by. Therefore, the flaw detection time and the number of flaw detections can be reduced.

Since the angle of the apex angle of the mirror surface 11b is 90 °, the length of the trajectory of the light beam from the portion of the subject 2 near the infrared camera 12 to the infrared camera 12 via the mirror surface 11b is the length of the subject 2. It is almost equal to the length of the trajectory of the light beam from the portion far from the infrared camera 12 to the infrared camera 12 via the mirror surface 11b. Therefore, the infrared camera 12 focuses 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, the reflector 14b is, for example, a radial reflector, and the light source 14a is the radial column thereof. It is placed on the focused line of the surface. The reflector 14b is directed toward the light passage port 11d and the mirror surface 11b of the reflector 11, and the central surface of the reflector 14b intersects the mirror surface 11b of the reflector 11. The shape of the reflector 14b may be another shape, for example, a semi-cylindrical surface type.

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

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

The heating light emitter 13 has one light heater 14, and the 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 deviated from the central axis 11e of the mirror surface 11b. Further, the heating light emitter 13 may have a plurality of light heaters 14 as in the heating light emitting device 13 in the first embodiment.

A dichroic mirror 15 is arranged between the light heater 14 and the mirror surface 11b so as to obliquely intersect 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 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 emitted by the optical heater 14).

The infrared camera 12 is arranged 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 toward the dichroic mirror 15, and the optical axis 12a of the infrared camera 12 is bent at 90 ° by the dichroic mirror 15. The optical axis 12a of the infrared camera 12 from the infrared camera 12 to the dichroic mirror 15 intersects the intersection of the central axis 11e of the mirror surface 11b 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.

The heating light emitted from the light heater 14 passes through the dichroic mirror 15. The heated light transmitted through the dichroic mirror 15 is reflected by the mirror surface 11b and is incident on the surface of the subject 2. Further, 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 radiated 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.

The infrared rays emitted from the surface of the subject 2 are reflected by the mirror surface 11b and further reflected by the dichroic mirror 15. The reflected infrared rays are incident on the infrared camera 12. As a result, the 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 provided. And are arranged coaxially. Therefore, even with a single light heater 14, the surface of the subject 2 can be uniformly heated over the entire circumference, and the subject reflected on the mirror surface 11b over the entire circumference of the subject 2. The infrared image of 2 can be captured by the infrared camera 12.

The position of the optical heater 14 and the position of the infrared camera 12 are exchanged, and the dichroic mirror 15 reflects the heating light emitted by the optical heater 14 and transmits light in a band other than the heating light band. May be good. In this case, as in the case of the first embodiment, the infrared camera 12 is directed toward the light passing port 11d and the mirror surface 11b of the reflector 11, and the optical axis 12a and the central axis 11e of the mirror surface 11b of the infrared camera 12 are directed to each other. They are arranged coaxially. Further, the optical heater 14 is arranged outside the dichroic mirror 15 in the radial direction with respect to the central axis 11e of the mirror surface 11b. The optical heater 14 is directed toward the dichroic mirror 15, and the optical axis of the optical 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 the direction orthogonal to the central axis 11e of the mirror surface 11b. Further, the reflector 14b is, for example, a parabolic reflector, and the light source 14a is arranged on the focused line of the paraboloid. Further, the reflector 14b is directed toward 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.

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

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

[Third Embodiment]
FIG. 3 is a schematic cross-sectional view of the flaw detector 10B according to the third embodiment.
In the following description, the difference between the flaw detector 10B of the third embodiment and the flaw detector 10 of the first embodiment will be described. Further, the components corresponding to each other between the flaw detection device 10B and the flaw detection device 10 are designated 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 cutting conical surface of the reflector 11. The subject 2 is inserted into the insertion slot 11c, and the subject 2 and the mirror surface 11b are arranged coaxially.

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

The infrared camera 12 is arranged at the tip of the light passing port 11d of the reflector 11 toward the light passing port 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 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 tilted with respect to the central axis 11e of the mirror surface 11b.

The heating light emitter 13 has one light heater 14. The light heater 14 is arranged at the tip of the light passing port 11d of the reflector 11 toward the light passing port 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 to the central axis 11e of the mirror surface 11b. The optical axis of the optical 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 have a plurality of light heaters 14 as in the heating light emitting device 13 in the first embodiment.

The light heater 14 and the infrared camera 12 are arranged on the same radius with respect to the central axis 11e of the mirror surface 11b. Further, the optical heater 14 is arranged inside the mirror surface 11b in the radial direction with respect to the central axis 11e with respect to the infrared camera 12. The infrared camera 12 may be arranged inside the mirror surface 11b in the radial direction with respect to the central axis 11e, with respect to the optical heater 14.
Both the light heater 14 and the infrared camera 12 are arranged outside the subject 2 in the radial direction with respect to the central axis 11e of the mirror surface 11b. Therefore, even if the subject 2 is fed in the direction of the central axis 11e by the feeding device 16, the subject 2 does not come into contact with the optical heater 14 and the infrared camera 12.

Subsequently, the operation and usage of the flaw detector 10 will be described.
First, the light source 14a is turned on with the feeding device 16 stopped. As a result, the subject 2 is heated.
Next, the light source 14a is turned off.
Next, when the image pickup process of the infrared camera 12 is performed, the infrared image of the subject 2 reflected on the mirror surface 11b is imaged by the infrared camera 12. The image pickup process of the infrared camera 12 may be performed during the lighting period of the light source 14a.
Next, the computer 19 is made to execute the 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 and the subject 2 is fed by the feeding device 16 in the direction of the central axis 11e of the mirror surface 11b by a predetermined distance, or the subject 2 is fed by the feeding device 16 around the central axis 11e by a predetermined angle. Rotate. The feeding device 16 may rotate the subject 2 and feed the subject 2 in the axial direction.
After that, the above-mentioned steps are repeated.

While the light source 14a is lit, the image pickup process of the infrared camera 12 may be performed while the subject 2 is moved by the feeding device 16.

In the present embodiment, the subject 2 is inserted into the insertion slot 11c, and the infrared camera 12 is directed toward the mirror surface 11b 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 fed in the circumferential direction and the axial direction by the feeding device 16, the entire surface of the subject 2 is within the flaw detection range by the infrared camera 12.

Further, since the optical heater 14 and the infrared camera 12 are arranged on the same side with respect to the subject 2, the infrared camera 12 can take a picture of the range irradiated with the heating light by the optical heater 14. That is, the portion shaded by the subject 2 is included in the shooting range of the infrared camera 12 only a little.

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 reflector, and the light source 14a is arranged on the focused line of the paraboloid. The reflector 14b is directed toward the light passage port 11d and the mirror surface 11b of the reflector 11, and the central surface of the reflector 14b intersects the mirror surface 11b of the reflector 11.

Further, the feeding device 16 does not rotate the subject 2 around the central axis 11e of the mirror surface 11b, but the revolution driving mechanism revolves the optical heater 14 and the infrared camera 12 around the central axis 11e of the mirror surface 11b. May be.

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

In this flaw detector 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 arranged symmetrically with respect to the other infrared camera 12 with respect to the central axis 11e of the mirror surface 11b.

Further, a plurality of optical heaters 14 are arranged in the circumferential direction with respect to the central axis 11e of the mirror surface 11b. When the number of the optical heaters 14 is 2, one optical heater 14 is symmetrically arranged with respect to the other optical heater 14 with respect to the central axis 11e of the mirror surface 11b.

The light source 14a may be a straight tube lamp, and the reflector 14b may be a parabolic 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. Further, the light source 14a is arranged on the focused line of the paraboloid surface which is the shape of the reflector 14b. Further, the reflector 14b is directed toward the light passage port 11d and the mirror surface 11b of the reflector 11, and the central surface of the reflector 14b intersects the mirror surface 11b 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 arranged symmetrically with respect to the light source 14a of the other light heater 14 with respect to the central axis 11e of the mirror surface 11b. The reflector 14b is directed toward the light passage port 11d and the mirror surface 11b of the reflector 11, and the central surface of the reflector 14b intersects the mirror surface 11b of the reflector 11.

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

A dichroic mirror 15 is arranged between the light heater 14 and the mirror surface 11b. The dichroic mirror 15 is arranged outside the subject 2 in the radial direction with respect to the central axis 11e of the mirror surface 11b. Therefore, even if the subject 2 moves in the direction of the central axis 11e, the subject 2 does not come into contact with the dichroic mirror 15. The angle formed by the central axis 14c of the reflector 14b and the normal 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, the infrared band, and transmits light in other bands (particularly, the heating light emitted by the optical heater 14).

The infrared camera 12 is arranged 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 toward the dichroic mirror 15, and the optical axis 12a of the infrared camera 12 is bent at 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.

The heating light emitted from the light heater 14 passes through the dichroic mirror 15. The heated light transmitted through the dichroic mirror 15 is reflected by the mirror surface 11b and is incident on the surface of the subject 2. Further, 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 radiated 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.

The infrared rays emitted from the surface of the subject 2 are reflected by the mirror surface 11b and further reflected by the dichroic mirror 15. The reflected infrared rays are incident on the infrared camera 12. As a result, the 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 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 on a focused line on the paraboloidal surface, which is the shape of the reflector 14b. The reflector 14b is directed toward the dichroic mirror 15, the light passage port 11d and the mirror surface 11b, and the central surface of the reflector 14b intersects the mirror surface 11b.

Further, the position of the optical heater 14 and the position of the infrared camera 12 are exchanged, and the dichroic mirror 15 reflects the heating light emitted by the optical heater 14, and the light in other bands (particularly, the sensing wavelength of the infrared camera 12). It may be used to transmit light in the band). In this case, the infrared camera 12 is directed toward the light passage port 11d and the mirror surface 11b of the reflector 11 as in the case of 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 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 arranged outside the dichroic mirror 15 in the radial direction with respect to the central axis 11e of the mirror surface 11b. The optical heater 14 is directed toward the dichroic mirror 15, and the optical axis of the optical heater 14 is bent at 90 ° by the dichroic mirror 15.

[Sixth Embodiment]
FIG. 6 is a schematic cross-sectional view of the flaw detector 10E according to the sixth embodiment.
In the following description, the difference between the flaw detector 10E of the sixth embodiment and the flaw detector 10D of the fifth embodiment will be described. Further, the components corresponding to each other between the flaw detector 10E and the flaw detector 10D are designated by the same reference numerals.

In the sixth embodiment, the number of the optical heaters 14 is a plurality. 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 optical 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 example]
In the above-mentioned first to sixth embodiments, the subject 2 is heated by the heating light emitted by the optical heater 14 incident on the subject 2. On the other hand, a heater of a method other than light heating may heat the subject 2. Heaters of methods other than light heating are listed below.

(1) The exciter may be used as a heater. The exciter heats the subject 2 by applying a high frequency vibration to the subject 2. The defect is heated by the frictional heat generated by the vibration in the defect existing in the subject 2. As the vibrating device, there is an ultrasonic vibrating device that vibrates the subject 2 by ultrasonic waves.

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

(3) A resistor-type heater in contact with the subject 2 generates heat due to electric energy to heat 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, the conductor is brought into contact with the subject 2.

(5) A dielectric heating type heater heats the subject 2 by generating a high-frequency electric field around the subject 2 and causing 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 ... infrared camera optical axis 14 ... optical heater (heater)
15 ... Dichroic mirror

Claims (9)

A reflector with a mirror surface formed in the shape of a conical surface on the inner surface,
An infrared camera that captures the mirror surface and
Equipped with a heater to heat the subject,
A flaw detection device in which the subject is arranged inside the mirror surface and on the central axis of the conical surface of the head, and the infrared camera captures the subject through the mirror surface. The heater is an optical heater that irradiates the heating light toward the mirror surface.
The flaw detection device according to claim 1, wherein the subject is heated by irradiating the subject with the heating light emitted by the light heater toward the subject by the mirror surface .
The flaw detection device according to claim 1 or 2, wherein the optical axis of the infrared camera and the central axis of the conical surface of the cutting cone are arranged coaxially. Further provided with a feeding device for feeding the subject in the direction of the central axis of the cutting conical surface.
The flaw detection device according to claim 1 or 2, wherein the infrared camera is arranged outside the subject in the radial direction with respect to the central axis of the conical surface. Further provided is a dichroic mirror which is arranged between the light heater and the mirror surface, transmits the heating light emitted by the light heater, and reflects light in the detection wavelength band of the infrared camera.
The dichroic mirror is tilted with respect to the central axis of the cutting conical surface,
The infrared camera is pointed at the dichroic mirror and
The flaw detection device according to claim 2, wherein the infrared camera captures an image of 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 device according to claim 5, wherein the optical axis of the bent infrared camera and the central axis of the conical surface of the cutting surface are arranged coaxially. Further provided with a dichroic mirror arranged between the infrared camera and the mirror surface, which transmits light in the sensing wavelength band of the infrared camera and reflects the heated light emitted by the optical heater.
The dichroic mirror is tilted with respect to the central axis of the cutting conical surface,
The light heater is pointed at the dichroic mirror and
The flaw detection device according to claim 2, wherein the optical heater irradiates the subject with the heating light through the dichroic mirror and the mirror surface. The flaw detection device according to claim 7, wherein the optical axis of the infrared camera and the central axis of the conical surface of the cutting surface are arranged coaxially. Further provided with a feeding device for feeding the subject in the direction of the central axis of the cutting conical surface.
The flaw detector according to claim 5 or 7, wherein the infrared camera, the optical heater, and the dichroic mirror are arranged outside the subject in the radial direction with respect to the central axis of the conical surface.

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