JP6638215B2 - Inspection device and inspection method - Google Patents

Description

  The present invention relates to an inspection device and an inspection method.

  2. Description of the Related Art In recent years, a defect of an object may be inspected using infrared rays. For example, Patent Literature 1 describes that a defect on an inner wall of a tunnel is inspected using infrared rays. In this inspection, the inner wall of the tunnel is irradiated with infrared rays. Then, the area irradiated with the infrared rays is photographed by an infrared camera. In this case, the region irradiated with the infrared rays is heated. When the inner wall of the tunnel includes a defect inside, the temperature rise due to infrared rays differs between the region where the defect exists and the region where the defect does not exist. In Patent Literature 1, the presence or absence of a defect is inspected by detecting a temperature difference between a region where a defect exists and a region where no defect exists using an infrared camera.

JP 2001-31709 A

  In order to detect a defect of an object by the method described in Patent Document 1, it is necessary to irradiate a region where the defect is located with light (specifically, infrared light). The inventor has studied a method capable of detecting a defect without irradiating a region where the defect is located with light.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to enable a defect to be detected without irradiating a region where the defect is located with light in inspection of a defect of an object. Is to do.

  An inspection device according to the present invention includes an optical system, a detection unit, and a determination unit. The optical system irradiates a part of the surface of the object with light for heating. The detection unit detects the above-mentioned surface temperature distribution in the above-mentioned part and its surroundings. The determining unit determines the presence or absence of a defect of the object based on the temperature distribution in the part and the surrounding when the part is irradiated with the light.

  In the inspection method according to the present invention, first, a part of the surface of the object is irradiated with light for heating from the optical system. Then, the temperature distribution of the above-mentioned surface in the above-mentioned part and its surroundings is detected by the detection unit. Then, the presence or absence of a defect of the object is determined based on the above-mentioned temperature distribution in the above-mentioned part and the surrounding when the above-mentioned part is irradiated to the above-mentioned part.

  In the inspection of a defect of an object, the defect can be detected without irradiating a region where the defect is located with light.

It is a figure showing the composition of the inspection device concerning a 1st embodiment. (A) is a figure for explaining the 1st example of the temperature distribution in an object, and (b) is a figure for explaining the 2nd example of the temperature distribution in an object. FIG. 5 is a diagram for describing a first example of a pattern of light applied to a surface of an object. It is a figure for explaining the 2nd example of the pattern of the light irradiated to the surface of the object. It is a figure for explaining the 3rd example of the pattern of the light irradiated to the surface of the object. It is a figure for explaining the 4th example of the pattern of the light irradiated to the surface of the object. It is a figure showing the composition of the inspection device concerning a 2nd embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof will not be repeated.

  In the following description, the determination unit 40, the reflection control unit 52, and the light control unit 54 do not show a configuration in hardware units but show blocks in function units. The determination unit 40, the reflection control unit 52, and the light control unit 54 include a CPU of any computer, a memory, a program loaded into the memory to realize the components of the drawing, a storage medium such as a hard disk storing the program, It is realized by an arbitrary combination of hardware and software with a focus on a network connection interface. There are various modifications in the method and apparatus for realizing the method.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration of the inspection device according to the first embodiment. This inspection device includes a light source unit 10, a reflection unit 20, a detection unit 30, a determination unit 40, and a reflection control unit 52. In the example shown in this figure, the light source unit 10, the reflection unit 20, and the detection unit 30 are mounted on the upper surface of the vehicle 60. The vehicle 60 is, for example, an automobile or a train. In the example shown in this figure, the vehicle 60 is moving. Thereby, the light source unit 10, the reflection unit 20, and the detection unit 30 move integrally with the vehicle 60. The determination unit 40 and the reflection control unit 52 may be mounted on the vehicle 60 or may not be mounted on the vehicle 60. The light source unit 10 and the reflection unit 20 constitute an optical system for emitting light toward the object 70. The inspection device is used for detecting whether or not the object 70 has a defect. In the example shown in this figure, the object 70 is an inner wall of a tunnel through which a vehicle (for example, an automobile or a train) passes.

  In the example shown in the figure, the light source unit 10 has one light source 100 (for example, a laser light source). The light source 100 (the light source unit 10) emits light having a wavelength for heating an object (specifically, for example, infrared light). In the example shown in the figure, the light source unit 10 emits light along the moving direction (horizontal direction) of the vehicle 60.

  The reflection unit 20 reflects light from the light source unit 10 toward the object 70. The reflection unit 20 is, for example, a micro mirror. The reflection section 20 has a reflection surface 200 that reflects light. On the reflection surface 200, for example, a metal film (for example, an Al film) is formed. Further, the reflecting section 20 can rotate the reflecting surface 200. In the example shown in this figure, the reflection unit 20 has a first rotation axis 212 and a second rotation axis 214 that cross each other (specifically, are orthogonal to each other). The reflection unit 20 is rotatable about each of the first rotation axis 212 and the second rotation axis 214. Thereby, the reflection unit 20 can two-dimensionally scan the light reflected on the reflection surface 200.

  Light from the reflection unit 20 is applied to a part of the surface of the object 70 (irradiation area 710). In the example shown in this drawing, this light forms a light irradiation pattern (a plurality of irradiation areas 710) on the surface of the object 70. In the example shown in this drawing, the plurality of irradiation areas 710 are generated at different timings. Specifically, these irradiation areas 710 are generated by emitting pulse light from the light source unit 10 a plurality of times while rotating the reflection surface 200 of the reflection unit 20. In this case, one irradiation region 710 is generated by one pulse light. The pulse width of the pulse light is, for example, 1 ms, and the repetition rate of the pulse light is, for example, 100 kHz.

  In the example shown in this figure, the reflection unit 20 is controlled by the reflection control unit 52. When the light source unit 10 emits pulse light having a predetermined repetition rate, the reflection control unit 52 receives a signal indicating the repetition rate from the light source unit 10. Then, the reflection control unit 52 controls the reflection unit 20 (specifically, the rotation speed of the reflection surface 200) based on this signal. Thereby, on the surface of the object 70, the interval between the plurality of irradiation regions 710 can be set to a desired interval.

  The vehicle 60 may be moving or may be stopped while the light source unit 10 and the reflecting unit 20 form the light irradiation pattern (the plurality of irradiation areas 710) on the object 70. Even if the vehicle 60 is moving, the time required for the light source unit 10 and the reflecting unit 20 to form the light irradiation pattern is very short. For this reason, when forming a light irradiation pattern using the light source unit 10 and the reflecting unit 20, it can be considered that the vehicle 60 is stationary even though the vehicle 60 is actually moving.

  The detection unit 30 detects the temperature distribution on the surface of the object 70. The detection unit 30 is, for example, an infrared thermograph. Specifically, the detection unit 30 detects infrared rays from the object 70. Thereby, the detecting unit 30 can detect the temperature distribution on the surface of the object 70. Note that the time required for the detection unit 30 to detect the temperature distribution is approximately one second. This time is much longer than the above-described pulse light cycle of the light source unit 10. For this reason, even if a plurality of irradiation regions 710 are formed at different timings using the above-described pulse light, the plurality of irradiation regions 710 are generated at the same time in the temperature distribution detected by the detection unit 30. Can be considered.

  The determining unit 40 determines whether the object 70 has a defect based on the temperature detected by the detecting unit 30. As will be described in detail later, the temperature distribution on the surface of the object 70 is determined based on the case where a defect (for example, a crack) exists around the region irradiated with light and the case where no defect exists around the region irradiated with light. Will be different.

  FIG. 2A is a diagram for describing a first example of a temperature distribution in the object 70. As shown in this figure, when a part of the surface of the object 70 (irradiation area 710) is irradiated with light, the irradiation area 710 is heated. Then, the heat of the irradiation area 710 is radially conducted from the irradiation area 710. The speed of heat conduction is substantially equal in regions located at an equal distance from the irradiation region 710 unless a defect (for example, a crack) exists in the object 70. Therefore, as shown in this figure, when there is no defect in the object 70, the contour line of the temperature distribution on the surface of the object 70 is located along the circumference of the circle centered on the irradiation area 710. Become.

  FIG. 2B is a diagram for explaining a second example of the temperature distribution in the object 70. In the example shown in this figure, the object 70 has a defect 720 (for example, crack). The defect 720 may be located on the surface of the object 70 or may be present inside the object 70. As shown in the figure, in the region where the defect 720 is located and in the vicinity thereof, the speed of heat conduction is slow. As a result, in the area where the defect 720 is located and in the vicinity thereof, the contour lines of the temperature distribution on the surface of the object 70 are distorted from the arc of the circle centered on the irradiation area 710. The determination unit 40 can determine the presence of the defect 720 based on the disturbance.

  FIG. 3 is a diagram for describing a first example of a pattern of light applied to the surface of the object 70. The pattern according to the example shown in the drawing is the same as the pattern according to the example shown in FIG. In the example shown in this drawing, light is irradiated only on one point (irradiation area 710) on the surface of the object 70. Also in this case, as described above, the presence of the defect 720 can be confirmed based on the temperature distribution around this one point (irradiation region 710).

  FIG. 4 is a diagram for explaining a second example of the pattern of light applied to the surface of the object 70. In the example shown in this drawing, each of the plurality of irradiation regions 710 is arranged at any of the plurality of grid points. In this case, the defect 720 can be detected with high sensitivity because the plurality of irradiation regions 710 form a complementary temperature distribution. Specifically, as described above, the defect 720 is detected by the disturbance in the temperature distribution formed by the irradiation region 710. This disorder increases as the apparent size of the defect 720 when viewed from the irradiation area 710 increases. In the example shown in this drawing, the defect 722 (defect 720) has a large apparent size when viewed from the irradiation region 712 which is a part of the plurality of irradiation regions 710. For this reason, the defect 722 can be detected with high sensitivity by the irradiation region 712. On the other hand, the defect 724 (defect 720) has a small apparent size when viewed from the irradiation area 712. Therefore, even if the irradiation region 712 is used, the defect 724 cannot be detected with high sensitivity. Even in such a case, in the example shown in this drawing, the defect 724 has a large apparent size when viewed from another irradiation region 710 (for example, the irradiation region 714 in the drawing). . Therefore, by using the irradiation region 714, the defect 724 can be detected with high sensitivity.

  FIG. 5 is a diagram for explaining a third example of the pattern of light applied to the surface of the object 70. In the example shown in this figure, the irradiation area 710 is formed in a lattice shape. Such a pattern is generated by scanning the light with the reflection unit 20 while continuously emitting light from the light source unit 10 (FIG. 1). In the example shown in this figure, the same effect as in the example shown in FIG. 4 can be obtained.

  FIG. 6 is a diagram for explaining a fourth example of the pattern of light applied to the surface of the object 70. In the example shown in this figure, the irradiation area 710 is formed in a curved shape. More specifically, in the example shown in this drawing, the irradiation area 710 draws a Lissajous figure. In the example shown in this figure, the same effect as in the example shown in FIG. 4 can be obtained.

  As described above, according to the present embodiment, the light source unit 10 and the reflecting unit 20 irradiate a part of the surface of the object 70 with light. The detecting unit 30 detects a temperature distribution on the surface of the object 70. When a part of the surface of the object 70 is irradiated with light, the detection unit 30 detects a temperature distribution generated around the part. The determining unit 40 determines the defect state of the object 70 based on the temperature distribution. In such a method, it is not necessary to observe physical unevenness generated on the surface of the object 70 due to the defect of the object 70. Therefore, even if the defect is minute, the defect can be detected with high accuracy. Furthermore, even if the defect is covered with a substance (for example, dirt located on the surface of the object 70), the defect can be detected with high accuracy.

  The object 70 is not limited to the inner wall of the tunnel. The object 70 may be, for example, a product flowing in a factory line. According to the present embodiment, even if the object 70 is such a product, a defect of the object 70 can be detected with high accuracy. When the object 70 is the above-described product, the light source unit 10, the reflection unit 20, and the detection unit 30 need not be mounted on the vehicle 60.

(Second embodiment)
FIG. 7 is a diagram illustrating a configuration of an inspection device according to the second embodiment, and corresponds to FIG. 1 of the first embodiment. The inspection apparatus according to the present embodiment has the same configuration as the inspection apparatus according to the first embodiment except for the following points.

  In the example shown in this figure, the light source unit 10 has a plurality of light sources 100. The plurality of light sources 100 emit light of different wavelengths (for example, infrared light). The detection unit 30 transmits to the light control unit 54 a signal indicating a temperature distribution when the light from the reflection unit 20 is applied to the object 70. The light control unit 54 switches the plurality of light sources 100 based on this signal. Thereby, the light control unit 54 controls the wavelength of the light emitted from the light source unit 10.

  According to the example shown in this figure, the object 70 can be irradiated with light having an appropriate wavelength to heat the object 70. In particular, the efficiency of converting light to heat may vary depending on the wavelength of the light. Therefore, the light of some wavelengths may not be able to efficiently heat the surface of the object 70. According to the example shown in this figure, even if light of such a wavelength is irradiated on the surface of the object 70, the detection unit 30 detects this and transmits a signal to the light control unit 54. The light control unit 54 receives this signal, and thereafter switches the light source 100. In this way, the object 70 can be irradiated with light having an appropriate wavelength to heat the object 70.

  As described above, the embodiments of the present invention have been described with reference to the drawings. However, these are merely examples of the present invention, and various configurations other than the above can be adopted.

Reference Signs List 10 light source unit 20 reflection unit 30 detection unit 40 determination unit 52 reflection control unit 54 light control unit 60 vehicle 70 object 100 light source 200 reflection surface 212 first rotation axis 214 second rotation axis 710 irradiation area 712 irradiation area 714 irradiation area 720 defect 722 defect 724 defect

Claims (8)

An optical system that irradiates a part of the surface of the object with light for heating, and forms a light irradiation pattern arranged on a plurality of lattice points on the surface of the object ,
A detection unit that detects a temperature distribution generated on the surface in the light irradiation pattern and around the light irradiation pattern by heat conduction from the light irradiation pattern to the periphery when the light irradiation pattern is formed ,
Based on the temperature distribution detected by the detection unit, a determination unit that determines the presence or absence of a defect of the object,
An inspection device comprising: The inspection device according to claim 1,
The optical system includes:
A light source unit for emitting the light,
A reflecting unit that reflects the light from the light source unit toward the object, and whose reflecting surface is rotatable,
An inspection device comprising: The inspection device according to claim 2,
An inspection device in which the light source unit, the detection unit, and the reflection unit are mounted on a vehicle. In the inspection device according to any one of claims 1 to 3,
An inspection apparatus comprising: a light control unit that controls a wavelength of the light based on the light irradiation pattern when the light irradiation pattern is formed and the temperature distribution around the light irradiation pattern . A part of the surface of the object is irradiated with light for heating from the optical system to form a light irradiation pattern arranged at a plurality of lattice points on the surface of the object ,
The heat radiation pattern from the light irradiation pattern when the light irradiation pattern is formed by the heat conduction to the surroundings, the light irradiation pattern and the temperature distribution generated on the surface around the detection pattern is detected by a detection unit,
An inspection method, wherein the presence or absence of a defect of the object is determined based on the temperature distribution detected by the detection unit. In the inspection method according to claim 5,
The optical system includes:
A light source unit for emitting the light,
A reflecting part whose reflecting surface is rotatable;
With
An inspection method, wherein the light from the light source unit is reflected toward the object by the reflection unit. In the inspection method according to claim 6,
An inspection method, wherein the light source unit, the detection unit, and the reflection unit are attached to a vehicle. In the inspection method according to any one of claims 5 to 7,
An inspection method, wherein a wavelength of the light is controlled based on the light irradiation pattern when the light irradiation pattern is formed and the temperature distribution around the light irradiation pattern .

Images