Internal inspection device and permeable tube

Abstract

This invention provides a technique for obtaining image data covering the entire circumference of the inner surface of an object to be inspected by irradiating it with light and taking images using the light section method. [Solution] An internal inspection device for imaging the inner surface of a hollow object under inspection comprises an imaging unit, a transparent fixing member, a light source, and a first mirror. The imaging unit is inserted into the inside of the object under inspection and is capable of imaging the inner surface of the object under inspection. The fixing member is fixed to the imaging unit, located radially outside the imaging unit, extends axially along the optical axis of the imaging unit, and is inserted into the inside of the object under inspection together with the imaging unit. The light source emits laser light directed toward one side in the axial direction. The first mirror reflects the laser light emitted from the light source and propagates it radially outward along its entire circumference. One end of the fixing member in the axial direction is located one side further axially than one end of the imaging unit in the axial direction. The first mirror is fixed to the fixing member one side further axially than one end of the imaging unit in the axial direction.

Description

Technical Field

[0001] The present invention relates to an inner surface inspection device for imaging the inner surface of a hollow inspection object, and a transparent tube used in the inner surface inspection device.

Background Art

[0002] In the manufacturing process of an engine mounted on an automobile, an inner surface inspection device is used to inspect whether there are defects such as scratches and cracks on the inner peripheral surface of a cylinder. Conventional inner surface inspection devices are described in, for example, Patent Document 1.

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0003] The cylinder inner surface observation device of Patent Document 1 includes an endoscope that can be inserted into a cylinder as an inspection object, an image processing device that processes a captured image by a CCD camera provided in the endoscope, and a light source that supplies light to a light guide provided in the endoscope. Further, the endoscope includes a hollow cylindrical scope body that can be inserted into the cylinder, a light guide formed by an optical fiber along the outer periphery of the scope body, and a cone mirror fixed to the tip of the scope body via a glass pipe. Further, a light shielding plate is provided in the scope body and the glass pipe. Thereby, the light emitted from the tip of the light guide is irradiated only to a part of the observation site on the inner surface of the cylinder.

[0004] In recent years, devices that use the light section method to measure the distance to an object and acquire its three-dimensional shape based on the obtained information have become widespread. Generally, when using the light section method, a "plane of light" is created by first irradiating the object with multiple linear laser beams, and then this laser light is irradiated onto the object. This makes it possible to reveal a contour shape equivalent to that which would be obtained if the object were cut along the "plane of light". Then, the revealed contour shape (the height of the object at the light section plane) is captured by an imaging device positioned at an angle shifted from the direction of laser beam irradiation, thereby capturing the contour shape of the object as an image. When using the light section method, because of the process involved, specific conditions must be met regarding the laser beam irradiation method and the relationship between the angle of light irradiation to the object and the angle of imaging from the imaging device. In the cylinder inner surface observation device of Patent Document 1, if the light section method were to be used, the light emitted from the tip of the light guide would be blocked by the structure constituting the cylinder inner surface observation device, making it impossible to form a light section plane. Therefore, it is not possible to obtain data for the entire circumference of the inner surface of the cylinder, which is the object to be imaged, in a single scan by the imaging device.

[0005] The object of the present invention is to provide a technique that allows image data to be obtained over the entire circumference of the inner surface of an object to be inspected by irradiating it with light over the entire circumference of the inner surface of the object to be inspected using the light section method. [Means for solving the problem]

[0006] The first invention is an internal inspection device for imaging the inner surface of a hollow object to be inspected, comprising: an imaging unit inserted into the inside of the object to be inspected and capable of imaging the inner surface of the object to be inspected; a transparent fixing member fixed to the imaging unit, located radially outside the imaging unit, extending axially along the optical axis of the imaging unit, and inserted into the inside of the object to be inspected together with the imaging unit; a light source that emits laser light directed toward one side in the axial direction; and a first mirror that reflects the laser light emitted from the light source and causes it to propagate radially outward over its entire circumference, wherein one end of the fixing member in the axial direction is located one side further in the axial direction than one end of the imaging unit in the axial direction, and the first mirror is fixed to the fixing member one side further in the axial direction than one end of the imaging unit in the axial direction.

[0007] The second invention relates to a transparent tube used in an internal inspection device for imaging the inner surface of a hollow object under inspection, the tube being fixed to an imaging unit capable of imaging the inner surface of the object under inspection, the first mirror extending axially from the radially outer side of the imaging unit with respect to the optical axis of the imaging unit, inserted into the inside of the object under inspection together with the imaging unit, and having one axial end of the first mirror located one axial side further than the axial end of the imaging unit, the first mirror being fixed to the first mirror on one axial side further than the axial end of the imaging unit, and reflecting laser light emitted from a light source that emits laser light directed axially toward one side, causing the laser light to propagate radially outward along its entire circumference. [Effects of the Invention]

[0008] According to the first and second inventions, laser light from a light source can be reflected by the first mirror inside the object under inspection and propagated around its entire circumference. The first mirror is positioned at one end of the imaging unit in the axial direction, that is, further towards the front than the front end of the imaging unit. Wiring for driving the light source is positioned on the other side of the imaging unit in the axial direction, that is, closer to the front. As a result, the imaging field of view of the imaging unit is not obstructed by wiring or the like, and imaging can be performed while irradiating the entire circumference of the inner surface of the object under inspection with laser light, thereby obtaining image data covering the entire circumference of the inner surface of the object under inspection. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view of the internal inspection device and the object being inspected. [Figure 2] Figure 2 is a longitudinal cross-sectional view of the internal inspection device and the object being inspected. [Figure 3] Figure 3 is a partial longitudinal cross-sectional view of the fixing member and the first mirror according to the first modified example. [Figure 4] Figure 4 is a perspective view of a part of the imaging unit, a support member, and an actuator. [Figure 5] Figure 5 is a longitudinal cross-sectional view of the internal inspection device and the object to be inspected according to the second modified example. [Figure 6] Figure 6 is a longitudinal cross-sectional view of the internal inspection device and the object to be inspected according to the third modified example. [Modes for carrying out the invention]

[0010] Hereinafter, exemplary embodiments of the present application will be described with reference to the drawings. In this application, the direction parallel to the optical axis of the imaging unit is referred to as the "axial direction," the direction perpendicular to the optical axis of the imaging unit is referred to as the "radial direction," and the direction along the arc centered on the optical axis of the imaging unit is referred to as the "circumferential direction." In this application, the terms "parallel" and "perpendicular" are used to describe directions, but they do not need to be strictly "parallel" or "perpendicular." In other words, the terms "parallel" and "perpendicular" in this application include cases where the direction is slightly tilted to the extent that the effects of the invention are achieved.

[0011] Furthermore, in this application, the tip side (rear side) of the imaging unit inserted inside the object under inspection is referred to as "one side in the axial direction," and the front side of the imaging unit is referred to as "the other side in the axial direction," and the shape and positional relationship of each part are described accordingly. In Figures 1 to 6 described later, "one side in the axial direction" is indicated as "a1," and "the other side in the axial direction" is indicated as "a2." In Figures 2, 3, 5, and 6 described later, "radial direction" is indicated as "r0."

[0012] <1. Configuration of the internal inspection device> Figure 1 is a perspective view of an internal inspection device 1 and an object to be inspected 9 according to one embodiment of the present invention. Figure 2 is a longitudinal cross-sectional view of the internal inspection device 1 and the object to be inspected 9. However, in Figures 1 and 2, the support member 50 and actuator 60, which will be described later, are not shown. Also, in Figures 1 and 2, the fixing member 20, which will be described later, is shown by a dashed line, and in the partially enlarged view of Figure 2, the fixing member 20 is shown by a solid line. This internal inspection device 1 is a device that creates three-dimensional data of the inner surface 91 based on image data acquired by imaging the inner surface 91 of a cylindrical object to be inspected 9, and inspects whether there is any abnormality in the condition of the inner surface 91. That is, the internal inspection device 1 images the inner surface 91 of a hollow object to be inspected 9. The internal inspection device 1 is used, for example, to inspect the inner surface of a cylinder mounted in an automobile engine. However, the internal inspection device 1 of the present invention may be a device for inspecting objects to be inspected other than cylinders, such as the inner surface of a hole provided in the wall of a building.

[0013] As shown in Figures 1 and 2, the internal inspection apparatus 1 of this embodiment comprises an imaging unit 10, a fixing member 20, a light source 30, a first mirror 41, a second mirror 42, a support member 50 (see Figure 4 described later), an actuator 60 (see Figure 4 described later), and a control unit 70.

[0014] The imaging unit 10 is a device that is supported by a support member 50, inserted inside the object to be inspected 9, and capable of imaging the inner surface 91 of the object to be inspected 9. In this embodiment, for example, a rigid endoscope is used for the imaging unit 10. As shown in Figure 2, the imaging unit 10 has a scope body 11, an objective lens 12, a plurality of relay lenses 13, and a camera 14.

[0015] The scope body 11 extends axially and cylindrically around the optical axis 100 of the imaging unit 10. The optical axis 100 of the imaging unit 10 is the optical axis of the objective lens 12. The imaging unit 10 is inserted into the inside of the object under inspection 9, moving approximately parallel to the optical axis 100 of the imaging unit 10. For example, stainless steel is used as the material for the scope body 11. The objective lens 12 is fixed near one end of the scope body 11 in the axial direction. In this embodiment, the objective lens 12 is directly fixed to the inner circumferential surface of the scope body 11. However, the objective lens 12 may also be fixed radially inward of the scope body 11 via another fixing mechanism. As a result, as shown in Figure 2, the hollow space 110 radially inward of the scope body 11 is closed near one end of the scope body 11 in the axial direction.

[0016] Multiple relay lenses 13 are provided at predetermined intervals in the hollow space 110 radially inside the scope body 11. In this embodiment, two relay lenses 13 are arranged in the hollow space 110. The relay lenses 13 are convex lenses that are convex toward one side and the other side in the axial direction, respectively.

[0017] Camera 14 is a device that captures an image projected onto the objective lens 12 via a plurality of relay lenses 13. Camera 14 can acquire image data of the inner surface 91 of the object under inspection 9 projected onto the objective lens 12. For example, a digital camera having an image sensor such as a CCD is used for camera 14. Camera 14 is positioned on the other side (front side) in the axial direction of the imaging unit 10. Laser light LB emitted from the light source 30 and irradiated onto the inner surface 91 of the object under inspection 9 is reflected by the inner surface 91 of the object under inspection 9 and enters the imaging unit 10. The laser light LB also passes through the objective lens 12 and continues to the other side in the axial direction, entering camera 14 via two relay lenses 13. In this way, camera 14 can acquire image data of the inner surface 91 of the object under inspection 9.

[0018] However, the structure of the imaging unit 10 may be different from the above structure. The imaging unit 10 may be formed, for example, by housing a super-small cone-shaped lens and a digital camera having an imaging element such as a CCD or a CMOS in a cylindrical transparent member.

[0019] The fixing member 20 is a transmissive (light-transmissive) member that is located on the outer side in the radial direction of the imaging unit 10 and extends in the axial direction along the optical axis 100 of the imaging unit 10. The fixing member 20 is a transmissive tube that extends axially and cylindrically around the optical axis 100 of the imaging unit 10 on the outer side in the radial direction of the imaging unit 10. The fixing member 20 is formed of a transmissive glass or a transmissive resin. One end portion of the fixing member 20 in the axial direction is located on one side in the axial direction rather than one end portion of the imaging unit 10 in the axial direction. Also, the fixing member 20 of the present embodiment has a sufficient thickness. The fixing member 20 is fixed to the outer side in the radial direction of the imaging unit 10 by a fixing mechanism (not shown). Thereby, the fixing member 20 is inserted into the inside of the inspection object 9 together with the imaging unit 10.

[0020] The light source 30 is a device capable of irradiating a laser beam LB with excellent directivity in the ON state. The light source 30 is connected to a power source via wiring 31 or the like. Also, the light source 30 is fixed to the fixing member 20 by a fixing mechanism (not shown). However, the light source 30 may be fixed to the imaging unit 10. Also, as shown in FIGS. 1 and 2, the light source 30 is disposed on the other side in the axial direction from the fixing member 20 and at a position separated from the imaging unit 10 and the fixing member 20. In the present embodiment, the light source 30 is disposed on the other side in the axial direction from the fixing member 20 and below the imaging unit 10 and the fixing member 20.

[0021] The light source 30 emits a laser beam LB, and irradiates the inner surface 91 of the inspection object 9 with the laser beam LB via the second mirror 42 and the first mirror 41. When in the ON state, the light source 30 emits a bundle of the laser beam LB in a direction orthogonal to the optical axis 100. The laser beam LB emitted from the light source 30 is reflected by the second mirror 42 and travels toward one side in the axial direction. That is, the light source 30 emits the laser beam LB traveling toward one side in the axial direction. Here, the "laser beam LB traveling toward one side in the axial direction" includes the laser beam LB that, even if it was traveling in a direction different from "one side in the axial direction" at the time of being emitted from the light source 30, travels toward "one side in the axial direction" by being reflected by the second mirror 42 or the like. In other words, as long as the laser beam LB is finally irradiated from the axial direction to the first mirror 41, the optical path in the middle is not a concern.

[0022] However, the position where the light source 30 is disposed and the direction in which the laser beam LB is emitted from the light source 30 are not limited to this. For example, the light source 30 may be disposed beside the other end portion in the axial direction of the fixing member 20. Also, for example, the light source 30 may be disposed inside the fixing member 20 in the radial direction.

[0023] A second mirror 42 is provided near the other axial end of the fixed member 20. The second mirror 42 is positioned above the light source 30. For example, a plane mirror is used for the second mirror 42. The second mirror 42 is fixed to the outer circumferential surface of the imaging unit 10 on the other axial side of the other axial end of the fixed member 20. However, the second mirror 42 may also be fixed to the other axial end of the fixed member 20. The second mirror 42 has a reflective surface 421 that faces the light source 30 and is inclined at 45° with respect to the optical axis 100. The reflective surface 421 faces the direction of the light source 30 and one side in the axial direction and is inclined at 45° with respect to the optical axis 100. However, the angle of inclination of the reflective surface 421 with respect to the optical axis 100 does not have to be 45°. As a result, the laser light LB emitted from the light source 30 is reflected by the reflective surface 421 and travels horizontally toward one side in the axial direction. In other words, the second mirror 42 can reflect each beam of laser light LB emitted from the light source 30 and propagate it in the axial direction. Furthermore, the second mirror 42 and the first mirror 41 are arranged in a straight line in the axial direction. The second mirror 42 reflects the laser light LB emitted from the light source 30 in the axial direction toward the first mirror 41.

[0024] Thus, by providing the second mirror 42, even when the light source 30 is positioned at a distance from the fixed member 20, the path of the laser beam LB emitted from the light source 30 can be changed by the second mirror 42, causing the laser beam LB to travel axially toward the first mirror 41. In this embodiment, the laser beam LB reflected by the second mirror 42 enters the thickness portion of the fixed member 20, that is, the portion of the material forming the fixed member 20, and continues to travel through the interior of the material forming the fixed member 20. In other words, the laser beam LB reflected by the second mirror 42 travels through the transparent glass or transparent resin forming the fixed member 20 and enters the first mirror 41.

[0025] The first mirror 41 is provided at one axial end of the fixing member 20. The first mirror 41 in this embodiment is a conical mirror. The first mirror 41 is fixed to the thickness portion of the fixing member 20, that is, to the portion of the material forming the fixing member 20. As described above, one axial end of the fixing member 20 is located one axial side further than one axial end of the imaging unit 10. That is, the first mirror 41 is fixed to the fixing member 20 one axial side further than one axial end of the imaging unit 10. The other axial surface of the first mirror 41 is a conical reflective surface 411 that is convex toward the other axial side. The reflective surface 411 is conical and inclined at 45° with respect to the optical axis 100. However, the angle of inclination of the reflective surface 411 with respect to the optical axis 100 does not have to be 45°. That is, the first mirror 41 has a conical reflective surface 411. In this embodiment, a commercially available conical mirror can be easily applied to the first mirror 41 of the internal surface inspection device 1.

[0026] However, as shown in the first modified example in Figure 3, the first mirror 41B may be formed by hollowing out a cone shape from one end face in the axial direction of the fixing member 20B and polishing the surface. That is, the first mirror 41B may be a cone-shaped recess that extends from one end face in the axial direction of the fixing member 20B toward the other end face in the axial direction. Furthermore, the recess forming the first mirror 41B in the first modified example is coated with a mirror coating. By forming the first mirror 41B in this way, the total number of parts in the internal inspection device 1 can be reduced.

[0027] As described above, in this embodiment, the reflective surface 411 of the first mirror 41 is convex toward the other side in the axial direction and is conical inclined at 45° with respect to the optical axis 100. As a result, the first mirror 41 can reflect the beam of laser light LB that has traveled from the other side in the axial direction to the one side in the axial direction, and direct it in a direction substantially perpendicular to the central axis 250 of the reflective surface 411 (see partially enlarged view in Figure 2). The central axis 250 is a straight line that passes through the vertex of the reflective surface 411 and is parallel to the optical axis 100. Furthermore, the laser light LB is reflected in different directions on a plane along an arc centered on the central axis 250, depending on the position at which it enters the first mirror 41. As a result, the first mirror 41 can reflect the laser light LB emitted from the light source 30 and direct it radially outward along its entire circumference.

[0028] As a result, optical cross-sections 300 are formed around the entire circumference of the first mirror 41 by the laser beam LB, which travels in a direction substantially perpendicular to the central axis 250. This allows the laser beam LB reflected by the first mirror 41 to be irradiated in a line (band) shape around the entire circumference of the first mirror 41 on the inner surface 91 of the object under inspection 9. In other words, the laser beam LB can be irradiated in a line (band) shape around the entire circumference of the vicinity of one end (tip) of the imaging unit 10 in the axial direction on the inner surface 91 of the object under inspection 9. As a result, the contour shape of the inner surface 91 of the object under inspection 9 around the vicinity of the tip of the imaging unit 10 can be made to stand out in a line (band) shape.

[0029] The laser beam LB, which is irradiated in a line (band) shape around the entire circumference near the tip of the imaging unit 10 onto the inner surface 91 of the object 9 under inspection, is diffusely reflected by the inner surface 91 of the object 9 under inspection. The reflected light from the inner surface 91 of the object 9 under inspection is then projected onto the objective lens 12 of the imaging unit 10. The camera 14 can capture the image projected onto the objective lens 12 via multiple relay lenses 13 and acquire it as image data. In other words, the inner surface inspection device 1 is a device that inspects the condition of the inner surface 91 of the object 9 under inspection using the "light section method".

[0030] As described above, in this embodiment, even though the light source 30 is positioned on the other axial side (front side) of the objective lens 12 of the imaging unit 10, the laser beam LB emitted from the light source 30 is reflected by the second mirror 42 and the first mirror 41 and irradiated onto the inner surface 91 of the object under inspection 9. With this configuration, the light source 30 and the wiring 31 for connecting the light source 30 to an external power source can be positioned on the other axial side (front side) of the objective lens 12 of the imaging unit 10. In other words, the wiring 31 for driving the light source 30 can be positioned on the other axial side (front side) of the tip of the imaging unit 10. As a result, the influence of the light source 30 and the wiring 31 on the imaging field of view of the imaging unit 10 can be suppressed. Furthermore, without the imaging field of view of the imaging unit 10 being obstructed by the light source 30 and the wiring 31, the laser beam LB can be irradiated over the entire circumference of the inner surface 91 of the object under inspection 9 and image can be captured by the camera 14, thereby obtaining image data covering the entire circumference of the inner surface of the object under inspection 9.

[0031] Figure 4 is a perspective view of a part of the imaging unit 10, the support member 50, and the actuator 60. The support member 50 is a plate-shaped member that supports the imaging unit 10. The fixing member 20 and the second mirror 42 are fixed to the imaging unit 10. The light source 30 and the first mirror 41 are fixed to the fixing member 20. In other words, the support member 50 directly or indirectly supports the imaging unit 10, the fixing member 20, the light source 30, the first mirror 41, and the second mirror 42, respectively.

[0032] The actuator 60 is a single-axis movement mechanism that supports a support member 50, an imaging unit 10 supported by the support member 50, a fixed member 20 and a second mirror 42 fixed to the imaging unit 10, and a light source 30 and a first mirror 41 fixed to the fixed member 20 so that they can reciprocate in the axial direction. In other words, the actuator 60 supports the support member 50, the imaging unit 10, the fixed member 20, and the light source 30 so that they can reciprocate in the axial direction. The actuator 60 transmits the driving force generated from a drive source such as a motor M1 to the support member 50 via a power transmission mechanism such as a ball screw. When the support member 50 moves, the imaging unit 10, the fixed member 20, the light source 30, the first mirror 41, and the second mirror 42 also move in the axial direction together with the support member 50. As a result, the actuator 60 can move the support member 50, the imaging unit 10, the fixed member 20, the light source 30, the first mirror 41, and the second mirror 42 relative to the object under inspection 9 in the axial direction. By using such an actuator 60, each part of the internal inspection device 1 can be advanced deep inside the object 9 to be inspected with a simple structure.

[0033] The control unit 70 is a means for controlling the operation of each part within the internal inspection device 1. The control unit 70 is composed of a personal computer having an arithmetic processing unit such as a CPU, memory such as RAM, and a storage unit such as a hard disk drive. The control unit 70 is also electrically connected to the imaging unit 10, the light source 30, and the actuator 60. By controlling the operation of the actuator 60, the control unit 70 inserts the support member 50, imaging unit 10, fixing member 20, light source 30, first mirror 41, and second mirror 42 of the internal inspection device 1 into the inside of the object to be inspected 9 and moves them in the axial direction. While moving each of these parts in the axial direction, the control unit 70 drives the light source 30 to continuously irradiate with laser light LB. Furthermore, by controlling the operation of the imaging unit 10, the control unit 70 causes the camera 14 to continuously take images.

[0034] The laser beam LB emitted from the light source 30 is reflected by the second mirror 42 and the first mirror 41, illuminating the inner surface 91 of the object under inspection 9 in a line (band) shape around the entire circumference near the tip of the imaging unit 10. Here, since the imaging unit 10, the fixing member 20, the light source 30, the first mirror 41, and the second mirror 42 are moving in the axial direction, the area on the inner surface 91 of the object under inspection 9 that is illuminated in a line (band) shape by the laser beam LB (the contour shape around the entire circumference near the tip of the imaging unit 10) also moves in the axial direction. The objective lens 12 of the imaging unit 10 projects the reflected light from the area on the inner surface 91 of the object under inspection 9 that is being illuminated by the laser beam LB and moving in the axial direction. The camera 14 of the imaging unit 10 can continuously acquire image data by continuously capturing the image projected onto the objective lens 12 while also moving in the axial direction itself.

[0035] Furthermore, the control unit 70 has a calculation unit 71. The function of the calculation unit 71 is realized by temporarily reading a computer program stored in the memory unit of the control unit 70 into memory, and having the processor perform calculation processing based on the computer program. The calculation unit 71 acquires three-dimensional data of the inner surface 91 of the object to be inspected 9 by stitching together a plurality of image data continuously captured by the camera 14 of the imaging unit 10. In other words, the calculation unit 71 acquires three-dimensional data based on the results obtained by imaging the inner surface 91 of the object to be inspected 9 with the imaging unit 10. Then, the control unit 70 can perform shape inspection, foreign object inspection, defect inspection, etc. of the inner surface 91 of the object to be inspected 9 by analyzing the acquired three-dimensional data.

[0036] <2. Other variations> Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. Below, other modifications will be described, focusing on the differences from the above embodiment.

[0037] <2-1. Second variation> Figure 5 is a longitudinal cross-sectional view of the internal inspection device 1 and the object to be inspected 9 according to the second modified example. In the example of Figure 5, the fixing member 20C has a different structure from the fixing member 20 in the above embodiment. For ease of understanding, the imaging unit 10 on the radially inner side of the fixing member 20C is shown with a dashed line in Figure 5.

[0038] In this modified example, the fixing member 20C has a cylindrical portion 21C and a flange portion 22C. The cylindrical portion 21C extends axially and cylindrically around the optical axis 100 of the imaging unit 10, on the radially outer side of the imaging unit 10. The flange portion 22C spreads radially outward from one axial end of the cylindrical portion 21C. The flange portion 22C also spreads circumferentially and annularly around the optical axis 100 of the imaging unit 10. The flange portion 22C is formed from transparent glass or transparent resin. One axial end of the fixing member 20C is located one axial side further than one axial end of the imaging unit 10. However, the thickness of the cylindrical portion 21C is thinner than the thickness of the fixing member 20 in the above embodiment.

[0039] In this modified example, the first mirror 41 is provided on the flange portion 22C. The first mirror 41 is a conical mirror. The first mirror 41 is fixed to the flange portion 22C on one side in the axial direction from one end of the imaging unit 10 in the axial direction. The reflective surface 411 on the other side in the axial direction of the first mirror 41 is convex toward the other side in the axial direction and is conical inclined at 45° with respect to the optical axis 100. However, the angle of inclination of the reflective surface 411 with respect to the optical axis 100 does not have to be 45°.

[0040] Furthermore, a second mirror 42 is fixed to the outer circumferential surface of the imaging unit 10 on the other axial side of the other axial end of the cylindrical portion 21C. The second mirror 42 has a reflective surface 421 that faces the light source 30 and is inclined at 45° with respect to the optical axis 100. The reflective surface 421 faces the direction of the light source 30 and one side in the axial direction and is inclined at 45° with respect to the optical axis 100. As a result, the laser light LB emitted from the light source 30 is reflected by the reflective surface 421 and travels axially toward one side in the axial direction. However, the angle at which the reflective surface 421 is inclined with respect to the optical axis 100 does not have to be 45°.

[0041] In this modified example, the thickness of the cylindrical portion 21C of the fixing member 20C is thin, and the reflective surface 421 of the second mirror 42 is located radially outward from the cylindrical portion 21C. Therefore, the laser beam LB reflected by the second mirror 42 travels through the layer of air La1 radially outward from the cylindrical portion 21C and is incident on the first mirror 41 fixed to the flange portion 22C. The laser beam LB is then reflected by the first mirror 41 and irradiates the inner surface 91 of the object under inspection 9 in a line (band) shape over the entire circumference around the tip of the imaging unit 10.

[0042] Thus, in this modified example, the thickness of the cylindrical portion 21C of the fixing member 20C is reduced, and the laser beam LB is configured to travel through the air layer La1 on the radially outer side of the cylindrical portion 21C. This reduces the amount of material constituting the fixing member 20C, leading to cost reduction. In addition, in the flange portion 22C of the fixing member 20C in this modified example, instead of providing a conical mirror as the first mirror 41, a recess like that in the first modified example described above may be provided.

[0043] <2-2. Third variation> Figure 6 is a longitudinal cross-sectional view of the internal inspection device 1 and the object to be inspected 9 according to the third modified example. In the example of Figure 6, the fixing member 20D has a different structure from the fixing member 20 in the above embodiment. For ease of understanding, the imaging unit 10 on the radially inner side of the fixing member 20D is shown with a dashed line in Figure 6.

[0044] The fixing member 20D extends axially and cylindrically around the optical axis 100 of the imaging unit 10, on the radially outer side of the imaging unit 10. One axial end of the fixing member 20D is located one axial side further than one axial end of the imaging unit 10. The fixing member 20D also has sufficient thickness. The fixing member 20D also has a through hole 200D. The through hole 200D penetrates axially through a portion of the thickness of the fixing member 20D, i.e., the portion of the material forming the fixing member 20D, in a portion of the circumferential direction. In this modified example, one axial end of the through hole 200D is closed by a cover portion 23D for fixing the first mirror 41. However, the cover portion 23D does not necessarily have to be provided if the first mirror 41 can be fixed to the fixing member 20D.

[0045] As described above, the first mirror 41 is provided on the cover portion 23D. The first mirror 41 is a conical mirror. The first mirror 41 is fixed to the cover portion 23D on one side in the axial direction from one end of the imaging unit 10 in the axial direction. The reflective surface 411 on the other side in the axial direction of the first mirror 41 is convex toward the other side in the axial direction and is conical inclined at 45° with respect to the optical axis 100. However, the angle of inclination of the reflective surface 411 with respect to the optical axis 100 does not have to be 45°.

[0046] Furthermore, a second mirror 42 is fixed to the outer circumferential surface of the imaging unit 10 on the other side in the axial direction from the other end of the fixing member 20D in the axial direction. The second mirror 42 has a reflective surface 421 that faces the light source 30 and is inclined at 45° with respect to the optical axis 100. The reflective surface 421 faces the direction of the light source 30 and one side in the axial direction and is inclined at 45° with respect to the optical axis 100. However, the angle of inclination of the reflective surface 421 with respect to the optical axis 100 does not have to be 45°. The second mirror 42, the through hole 200D, and the first mirror 41 are arranged in a straight line in the axial direction. As a result, the laser light LB emitted from the light source 30 is reflected by the reflective surface 421, travels through the through hole 200D toward one side in the axial direction, and enters the first mirror 41. The laser beam LB is then reflected by the first mirror 41 and irradiates the inner surface 91 of the object to be inspected 9 in a line (band) shape around the entire circumference near the tip of the imaging unit 10.

[0047] Thus, in this modified example, a through hole 200D is provided in the fixing member 20D, and the laser beam LB is configured to advance through the through hole 200D. This reduces the amount of material used to construct the fixing member 20D, leading to cost reduction. In addition, in the lid portion 23D of the fixing member 20D in this modified example, instead of providing a conical mirror as the first mirror 41, a recess like that in the first modified example described above may be provided.

[0048] The internal inspection device and the details of the permeable tube may be modified as appropriate without departing from the spirit of the present invention. Furthermore, the elements that appear in the above embodiments and modifications may be combined as appropriate without creating any inconsistencies.

[0049] <3. Summary> This technology can be configured as follows:

[0050] (1): An internal surface inspection device for imaging the inner surface of a hollow object to be inspected, An imaging unit is inserted inside the object to be inspected and is capable of imaging the inner surface of the object to be inspected, A transparent fixing member is fixed to the imaging unit, located radially outside the imaging unit, extending axially along the optical axis of the imaging unit, and inserted together with the imaging unit into the inside of the object under inspection; A light source that emits laser light directed in one direction along the axis, A first mirror that reflects the laser light emitted from the light source and propagates it radially outward along the entire circumference, It has, One end of the fixing member in the axial direction is located one axial side further than the one axial end of the imaging unit. An internal surface inspection device wherein the first mirror is fixed to the fixing member on one side in the axial direction, rather than on one end in the axial direction of the imaging unit.

[0051] (2): The internal inspection device described in (1), The fixing member is a transparent tube that extends axially from the radially outer side of the imaging unit, with respect to the optical axis of the imaging unit, and is inserted into the inside of the object to be inspected together with the imaging unit, in an internal inspection device.

[0052] (3): An internal inspection device as described in (1) or (2), The first mirror is a conical mirror having a conical reflective surface, in an internal surface inspection device.

[0053] (4): An internal inspection device as described in (1) or (2), The first mirror is an internal surface inspection device, wherein the first mirror is a conical recess that extends from one end face in the axial direction toward the other end face in the axial direction of the fixed member.

[0054] (5): An internal inspection device as described in any one of (1) to (4), A second mirror is fixed to the other axial end of the fixing member, or fixed to the outer circumferential surface of the imaging unit on the other axial side of the other axial end of the fixing member, and reflects the laser light emitted from the light source axially toward the first mirror. An internal inspection device further possessing the following.

[0055] (6):(5) The internal inspection device described above, The fixing member is formed from permeable glass or permeable resin. An internal surface inspection device wherein the laser light reflected by the second mirror travels through the glass or resin and enters the first mirror.

[0056] (7): An internal inspection device as described in (5) or (6), The aforementioned fixing member is A cylindrical portion extending axially and cylindrically with respect to the optical axis of the imaging unit, A flange portion that extends radially outward from one end in the axial direction of the cylindrical portion and extends circumferentially and annularly around the optical axis of the imaging portion, It has, The first mirror is provided on the flange portion, An internal surface inspection device wherein the laser light reflected by the second mirror travels through the layer of air radially outside the cylindrical portion and enters the first mirror.

[0057] (8): An internal inspection device as described in any one of (1) to (7), A support member that supports the imaging unit, An actuator that supports the support member, the imaging unit, the fixing member, and the light source so that they can reciprocate in the axial direction, An internal inspection device further possessing the following.

[0058] (9): An internal inspection device as described in any one of (1) to (8), An internal surface inspection device having a calculation unit that acquires three-dimensional data based on the results obtained by imaging the inner surface of the object to be inspected with the imaging unit.

[0059] (10): A transparent tube used in an internal inspection device for imaging the inner surface of a hollow object under inspection, It is fixed to an imaging unit capable of imaging the inner surface of the object to be inspected, and extends axially from the radially outer side of the imaging unit with respect to the optical axis of the imaging unit, and is inserted together with the imaging unit into the inside of the object to be inspected, One end of itself in the axial direction is located one axial side further than the one axial end of the imaging unit. A transparent tube to which a first mirror, which reflects laser light emitted from a light source that emits laser light directed toward one side in the axial direction and propagates it radially outward along its entire circumference, is fixed at one end in the axial direction, further than the axial end of the imaging unit. [Industrial applicability]

[0060] This invention can be used in internal inspection devices and permeable tubes. [Explanation of symbols]

[0061] 1. Internal Inspection Device 9. Object under inspection 10 Imaging Unit 11. Scope body of the imaging unit 12. Objective lens of the imaging unit 14. Camera in the imaging unit 20, 20B, 20C, 20D Fixing members 21C Cylindrical part of the fixing member 22C Flange portion of fixing member 30 light source 31. Wiring of light sources 41,41B First Mirror 42 Second Mirror 50 Support member 60 Actuators 70 Control Unit 71 Arithmetic section 91 Inner surface of the object being inspected 100 Optical axis of the imaging unit 300 light section 411 Reflecting surface of the first mirror 421 Reflecting surface of the second mirror LB laser light La1 Air layer

Claims

1. An internal surface inspection device for imaging the inner surface of a hollow object under inspection, An imaging unit is inserted inside the object to be inspected and is capable of imaging the inner surface of the object to be inspected, A transparent fixing member is fixed to the imaging unit, located radially outside the imaging unit, extending axially along the optical axis of the imaging unit, and inserted together with the imaging unit into the inside of the object under inspection; A light source that emits laser light directed in one direction along the axis, A first mirror that reflects the laser light emitted from the light source and propagates it radially outward along its entire circumference, It has, One end of the fixing member in the axial direction is located one axial side further than the one axial end of the imaging unit. An internal inspection device in which the first mirror is fixed to the fixing member on one side in the axial direction, rather than on one end in the axial direction of the imaging unit.

2. An internal inspection device according to claim 1, The fixing member is a transparent tube that extends axially from the radially outer side of the imaging unit, with respect to the optical axis of the imaging unit, and is inserted into the inside of the object to be inspected together with the imaging unit, in an internal inspection device.

3. An internal inspection device according to claim 1, The first mirror is a conical mirror having a conical reflective surface, in an internal surface inspection device.

4. An internal inspection device according to claim 1, The first mirror is an internal surface inspection device, wherein the first mirror is a conical recess that extends from one end face in the axial direction toward the other end face in the axial direction of the fixed member.

5. An internal inspection device according to any one of claims 1 to 4, A second mirror is fixed to the other axial end of the fixing member, or fixed to the outer circumferential surface of the imaging unit on the other axial side of the other axial end of the fixing member, and reflects the laser light emitted from the light source axially toward the first mirror. An internal inspection device further possessing the following.

6. An internal surface inspection device according to claim 5, The fixing member is formed from permeable glass or permeable resin. An internal surface inspection device wherein the laser light reflected by the second mirror travels through the glass or resin and enters the first mirror.

7. An internal surface inspection device according to claim 5, The aforementioned fixing member is A cylindrical portion extending axially and cylindrically with respect to the optical axis of the imaging unit, A flange portion that extends radially outward from one end in the axial direction of the cylindrical portion and extends circumferentially and annularly around the optical axis of the imaging portion, It has, The first mirror is provided on the flange portion, An internal surface inspection device wherein the laser light reflected by the second mirror travels through the layer of air radially outside the cylindrical portion and enters the first mirror.

8. An internal inspection device according to any one of claims 1 to 4, A support member that supports the imaging unit, An actuator that supports the support member, the imaging unit, the fixing member, and the light source so that they can reciprocate in the axial direction, An internal inspection device further possessing the following.

9. An internal inspection device according to any one of claims 1 to 4, An internal surface inspection device having a calculation unit that acquires three-dimensional data based on the results obtained by imaging the inner surface of the object to be inspected with the imaging unit.

10. A transparent tube used in an internal inspection device that images the inner surface of a hollow object under inspection, It is fixed to an imaging unit capable of imaging the inner surface of the object to be inspected, and extends axially from the radially outer side of the imaging unit with respect to the optical axis of the imaging unit, and is inserted together with the imaging unit into the inside of the object to be inspected, One end of itself in the axial direction is located one axial side further than the one axial end of the imaging unit. A transparent tube to which a first mirror, which reflects laser light emitted from a light source that emits laser light directed toward one side in the axial direction and propagates it radially outward along its entire circumference, is fixed at one end in the axial direction, further than the axial end of the imaging unit.

Images