Inspection equipment

Abstract

To provide an inspection device that can inspect the inner surface of small-diameter objects with high precision. [Solution] The inspection device for inspecting the inner surface 60a of an object to be inspected 60 is equipped with a distance meter having multiple channels. Each channel is equipped with an optical fiber 21 that transmits measurement light 30 from a light source and a sensor head 22 provided at the tip of the optical fiber 21. The sensor head 22 includes a collimating lens 23 that emits the measurement light 30 emitted from the tip of the optical fiber 21 as parallel light toward the inner surface 60a of the object to be inspected 60, and also causes scattered light from the inner surface 60a of the object to be inspected 60 to be incident on the tip of the optical fiber 21. The multiple sensor heads 22 are arranged in a ring around the central axis Ax such that the measurement light 30 is irradiated radially from the central axis Ax toward the inner surface 60a of the object to be inspected 60.

Description

Technical Field

[0001] The present invention relates to an inspection apparatus.

Background Art

[0002] Conventionally, an inspection apparatus is known that inspects the inner peripheral surface by obtaining a light cutting image from an annular beam image obtained by irradiating an annular laser beam onto the inner peripheral surface of an inspection object while moving along the axial direction of the tubular inspection object (see, for example, Patent Document 1).

[0003] In this inspection apparatus, an annular beam that spreads in the circumferential direction from a point on the central axis is used in the space inside the inspection object. The annular beam is incident on the inner peripheral surface of the inspection object, and an annular beam image is acquired by a camera arranged on the central axis of the inspection object. By analyzing this annular beam image, information regarding the inner diameter, surface shape, presence or absence of defects on the inner peripheral surface, etc. of the inspection object can be obtained.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above-described inspection apparatus, during inspection, a light probe including a light module that irradiates an annular beam onto the inner peripheral surface of the inspection object and a camera that receives the light reflected from the inner peripheral surface of the inspection object is moved to enter the space inside the inspection object. When the inspection object has a small diameter and a deep depth, since the camera also needs to be inserted into the inspection object, it is necessary to use a small camera. As a result, a camera with a low number of pixels has to be adopted, and there is a risk that the measurement accuracy will decrease.

[0006] This invention has been made in view of these circumstances, and its purpose is to provide an inspection device that can inspect the inner circumferential surface of a small-diameter object with high precision. [Means for solving the problem]

[0007] To solve the above problems, an inspection apparatus according to one aspect of the present invention is an inspection apparatus for inspecting the inner surface of an object to be inspected, and comprises a distance meter having a plurality of channels. The sensor head includes a collimating lens that emits measurement light emitted from the tip of an optical fiber as parallel light toward the inner surface of the object to be inspected, and also causes scattered light from the inner surface of the object to be inspected to be incident on the tip of the optical fiber. Each channel comprises an optical fiber that transmits measurement light from a light source and a sensor head provided at the tip of the optical fiber. The plurality of sensor heads are arranged in a ring around a central axis such that measurement light is irradiated radially from the central axis toward the inner surface of the object to be inspected.

[0008] Another aspect of the present invention is also an inspection device. This device is an inspection device for inspecting the inner surface of an object to be inspected, and comprises a distance meter having a plurality of channels. Each channel comprises an optical fiber that transmits measurement light from a light source and a sensor head provided at the tip of the optical fiber. The plurality of sensor heads are arranged in a ring around the central axis so that the measurement light is irradiated parallel to the central axis of the object to be inspected, and further comprises a conical mirror that reflects the measurement light from the plurality of sensor heads and irradiates the measurement light radially toward the inner surface of the object to be inspected. The sensor head includes a collimating lens that emits the measurement light emitted from the tip of the optical fiber as parallel light toward the conical mirror, and also causes the scattered light from the inner surface of the object to be inspected, reflected by the conical mirror, to enter the tip of the optical fiber. [Effects of the Invention]

[0009] According to the present invention, an inspection device is available that can inspect the inner circumferential surface of a small-diameter object with high precision. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic cross-sectional view of the inspection apparatus according to the embodiment. [Figure 2] This is a schematic longitudinal cross-sectional view of the optical probe according to the first embodiment. [Figure 3] This is a schematic cross-sectional view of the optical probe according to the first embodiment. [Figure 4] This is a schematic longitudinal cross-sectional view of the optical probe according to the second embodiment. [Figure 5] This is a schematic cross-sectional view of the optical probe according to the second embodiment. [Modes for carrying out the invention]

[0011] In the following, identical or equivalent components and members shown in each drawing will be denoted by the same reference numeral, and redundant explanations will be omitted as appropriate. Furthermore, the dimensions of the members in each drawing will be enlarged or reduced as appropriate for ease of understanding. Additionally, some members that are not important for explaining the embodiment will be omitted from the drawings.

[0012] Figure 1 is a schematic cross-sectional view of the inspection device 100 according to the embodiment. The inspection device 100 inspects the inner surface of the object to be inspected 60 by irradiating it with an annular beam.

[0013] The inspection device 100 comprises a housing 50 and a support plate 51 arranged in the internal space of the housing 50. The housing 50 can move on the floor surface by wheels 53. The internal space of the housing 50 is divided into two spaces, upper and lower, by the support plate 51. The upper space will be called the inspection room 50A, and the lower space will be called the waiting room 50B. In this embodiment, the positional relationship between the inspection room 50A and the waiting room 50B is upper and lower, but this is not necessarily required. For example, they may be arranged side by side horizontally. Alternatively, the upper and lower relationship between the inspection room 50A and the waiting room 50B may be reversed.

[0014] A workpiece mounting section 52 is fixed on a support plate 51, and a tubular object to be inspected, for example, 60 is held on the workpiece mounting section 52. The object to be inspected 60 is fixed in a position where its central axis is parallel to the vertical direction. An opening 54 is provided directly below the internal space of the object to be inspected 60, passing through the support plate 51 and the workpiece mounting section 52 in the vertical direction.

[0015] The inspection device 100 is equipped with a non-contact distance meter 20. The non-contact distance meter is also called a non-contact distance sensor, non-contact displacement meter, or non-contact displacement sensor. The non-contact distance meter 20 may be a non-contact distance meter that utilizes optical coherence tomography (OCT). OCT is a well-known technology used in devices such as fundus imaging equipment. The OCT may be wavelength-swept OCT or spectral domain OCT. The non-contact distance meter 20 has multiple channels and is capable of monitoring displacement at multiple points. The number of channels in the non-contact distance meter 20 may be, for example, 4 channels, 8 channels, or 16 channels.

[0016] The non-contact distance meter 20 comprises an optical probe 10, a sensor body 15, and an optical fiber bundle 16 connecting the optical probe 10 and the sensor body 15.

[0017] The optical probe 10 is supported on a moving mechanism 18 by a rod-shaped support member 12. The moving mechanism 18 is configured to move the optical probe 10 and the support member 12 along the central axis of the object to be inspected 60. The moving mechanism 18 is controlled by a control unit 42. In standby mode when no inspection is being performed, the optical probe 10 is waiting in a waiting chamber 50B below the object to be inspected 60 (below the support plate 51). During inspection, the optical probe 10 is raised by the moving mechanism 18 through the opening 54 and enters the inspection chamber 50A, entering the space inside the object to be inspected 60. The detailed configuration of the optical probe 10 will be described later.

[0018] The sensor main body 15 is housed in the standby chamber 50B of the housing 50. The sensor main body 15 may house a light source, a detector, etc. necessary to realize OCT for each channel. The sensor main body 15 and the optical probe 10 are connected by an optical fiber bundle 16. The optical fiber bundle 16 is a bundle of optical fibers for each channel. The measurement light from the light source in the sensor main body 15 is guided to the optical probe 10 via the optical fiber bundle 16. Also, the scattered light generated on the inner peripheral surface of the inspection object 60 by the irradiation of the measurement light from the optical probe 10 is captured by the optical probe 10 and guided to the detector in the sensor main body 15 via the optical fiber bundle 16. For example, by OCT, the inner diameter value of the inspection object 60 is measured for each channel.

[0019] The control unit 42 is also housed in the standby chamber 50B of the housing 50. The control unit 42 controls the sensor main body 15 and the moving mechanism 18 according to a command from the upper controller 40. The inner diameter value data for each channel obtained by the sensor main body 15 is input to the analysis unit 41 of the upper controller 40. The analysis unit 41 creates a cross-sectional profile of the inspection object 60 based on the input inner diameter value data.

[0020] (First Embodiment) FIG. 2 is a schematic longitudinal sectional view of the optical probe 10 according to the first embodiment. FIG. 3 is a schematic cross-sectional view of the optical probe 10 according to the first embodiment.

[0021] Here, the number of channels of the non-contact distance meter 20 is set to 8 channels. Each channel of the non-contact distance meter 20 includes an optical fiber 21 that transmits measurement light from a light source, and a sensor head 22 provided at the tip of the optical fiber 21.

[0022] The optical probe 10 is equipped with eight sensor heads 22. Each sensor head 22 includes a collimating lens 23. The collimating lens 23 directs the measurement light 30 emitted from the tip of the optical fiber 21 as parallel light toward the inner surface 60a of the object to be inspected 60. The collimating lens 23 also directs the scattered light generated on the inner surface 60a of the object to be inspected 60 due to the irradiation of the measurement light toward the tip of the optical fiber 21.

[0023] As shown in Figure 3, the eight sensor heads 22 are arranged in a ring around the central axis Ax of the object to be inspected 60 so that the measurement light 30 is irradiated radially from the central axis Ax toward the inner surface 60a of the object to be inspected 60. The eight sensor heads 22 are arranged at a predetermined angular interval θ (θ = 45° in Figure 2) around the central axis Ax of the object to be inspected 60. As shown in Figure 2, the optical fiber 21 is arranged along the central axis Ax of the object to be inspected 60, and the optical axis of the sensor head 22 (i.e., the optical axis of the collimating lens 23) is directed by bending the tip of the optical fiber 21 at approximately a right angle to the central axis Ax. By arranging the eight sensor heads 22 as shown in Figure 2 and irradiating the measurement light 30 at eight points on the inner surface 60a of the object to be inspected 60, radius values ​​can be obtained at eight points, and a cross-sectional profile of the object to be inspected 60 can be constructed.

[0024] According to this first embodiment, since it is not necessary to insert a camera into the object to be inspected 60 as in the light section method, the inner diameter value of the small-diameter object to be inspected 60 can be obtained with high precision. Furthermore, in this first embodiment, since the optical probe 10 does not have any movable parts, durability can be improved compared to a method that uses, for example, a rotating mirror.

[0025] In this first embodiment, the tip of the optical fiber 21 is bent to make the optical path of the measurement light 30 approximately perpendicular to the central axis, and the measurement light 30 is irradiated onto the inner circumferential surface 60a. Since no reflective material such as a conical mirror is used to bend the optical path of the measurement light 30, the configuration of the optical probe 10 can be simplified.

[0026] In this example, the non-contact distance meter 20 has 8 channels, so radius values ​​are obtained at 8 points on the inner surface 60a of the object being inspected 60. However, by increasing the number of channels, radius values ​​can be obtained at more points, allowing for the construction of a more accurate cross-sectional profile. Furthermore, by rotating the object being inspected 60, radius values ​​can also be obtained at more points, allowing for the construction of a more accurate cross-sectional profile.

[0027] (Second Embodiment) Figure 4 is a schematic longitudinal cross-sectional view of the optical probe 110 according to the second embodiment. Figure 5 is a schematic transverse cross-sectional view of the optical probe 110 according to the second embodiment.

[0028] Here too, the non-contact distance meter 20 has 8 channels. Each channel of the non-contact distance meter 20 includes an optical fiber 21 that transmits measurement light from a light source, and a sensor head 22 provided at the tip of the optical fiber 21.

[0029] The optical probe 10 comprises eight sensor heads 22 and a conical mirror 112. As shown in Figure 5, the eight sensor heads 22 are arranged in a ring around the central axis Ax such that the measurement light 30 is irradiated parallel to the central axis Ax of the object to be inspected 60. The eight sensor heads 22 are arranged at a predetermined angular interval θ (θ = 45° in Figure 2) around the central axis Ax of the object to be inspected 60.

[0030] Each sensor head 22 includes a collimating lens 23. The collimating lens 23 directs the measurement light 30 emitted from the tip of the optical fiber 21 toward the conical mirror as parallel light. The collimating lens 23 also directs scattered light from the inner surface 60a of the object to be inspected 60, which has been reflected by the conical mirror 112, toward the tip of the optical fiber 21.

[0031] A conical mirror 112 is positioned where the measurement light 30 from the eight sensor heads 22 is incident. The conical mirror 112 has a conical reflective surface. The axis of rotation of this conical surface coincides with the central axis Ax. The conical mirror 112 reflects the measurement light 30 from the eight sensor heads 22 and irradiates the measurement light 30 radially toward the inner circumferential surface 60a of the object to be inspected 60. When the apex angle of the conical mirror 112 is 90°, the measurement light 30 from each sensor head 22 is reflected perpendicular to the direction of incidence, and radial measurement light 30 is irradiated. As shown in Figure 5, by arranging the eight sensor heads 22 and irradiating the measurement light 30 onto eight areas of the inner circumferential surface 60a of the object to be inspected 60, the average radius value of the beam-irradiated area in the eight areas can be obtained, and the cross-sectional profile of the object to be inspected 60 can be constructed.

[0032] In this second embodiment, as in the light section method, it is not necessary to insert the camera into the object to be inspected 60, so the inner diameter value of the small-diameter object to be inspected 60 can be obtained with high precision. In addition, in this second embodiment, the optical probe 10 does not have any movable parts, so durability can be improved.

[0033] In this second embodiment, by arranging the conical mirror 112, the optical path of the measurement light 30 is made approximately perpendicular to the central axis, and the measurement light 30 is irradiated onto the inner circumferential surface 60a. By using the conical mirror 112, it is only necessary to simply bundle the optical fibers 21 of each channel, so the adjustment of the optical path (optical axis) of the measurement light 30 is easier compared to the first embodiment.

[0034] In this example, the non-contact distance meter 20 has 8 channels, so the average radius value is obtained for 8 areas on the inner surface 60a of the object being inspected 60. However, by increasing the number of channels, the average radius value can be obtained for a larger area, allowing for the construction of a more accurate cross-sectional profile. Furthermore, by rotating the object being inspected 60, the average radius value can also be obtained for a larger area, allowing for the construction of a more accurate cross-sectional profile.

[0035] Any combination of the embodiments and modifications described above is also useful as an embodiment of the present invention. The new embodiments resulting from these combinations possess the combined effects of the respective embodiments and modifications. [Explanation of Symbols]

[0036] 10, 110 Optical probe, 12 Support member, 15 Sensor body, 16 Optical fiber bundle, 18 Moving mechanism, 20 Non-contact distance meter, 21 Optical fiber, 22 Sensor head, 23 Collimating lens, 30 Measurement light, 40 Higher-level controller, 41 Analysis unit, 42 Control unit, 50 Housing, 51 Support plate, 52 Workpiece mounting unit, 53 Wheels, 54 Aperture, 60 Object to be inspected, 100 Inspection device, 112 Conical mirror.

Claims

1. An inspection device for inspecting the inner surface of an object to be inspected, Equipped with a rangefinder having multiple channels, Each channel comprises an optical fiber for transmitting measurement light from a light source and a sensor head provided at the tip of the optical fiber. The sensor head includes a collimating lens that emits the measurement light emitted from the tip of the optical fiber as parallel light toward the inner surface of the object to be inspected, and also causes scattered light from the inner surface of the object to be inspected to enter the tip of the optical fiber. An inspection device characterized in that the plurality of sensor heads are arranged in a ring around the central axis such that the measurement light is irradiated radially from the central axis toward the inner circumferential surface of the object to be inspected.

2. The inspection apparatus according to claim 1, characterized in that the distance meter is a non-contact distance meter utilizing optical coherence tomography (OCT).

3. The inspection apparatus according to claim 1 or 2, characterized in that the plurality of sensor heads are arranged at predetermined angular intervals around the central axis of the object to be inspected.

4. An inspection device for inspecting the inner surface of an object to be inspected, Equipped with a rangefinder having multiple channels, Each channel comprises an optical fiber that transmits measurement light from a light source, and a sensor head provided at the tip of the optical fiber. Multiple sensor heads are arranged in a ring around the central axis such that the measurement light is irradiated parallel to the central axis of the object to be inspected. The system further comprises a conical mirror that reflects the measurement light from multiple sensor heads and irradiates the measurement light radially toward the inner surface of the object to be inspected, The inspection apparatus is characterized in that the sensor head emits the measurement light emitted from the tip of the optical fiber as parallel light toward the conical mirror, and includes a collimating lens that causes the scattered light from the inner surface of the object to be inspected, reflected by the conical mirror, to be incident on the tip of the optical fiber.

5. The inspection apparatus according to claim 4, characterized in that the distance meter is a non-contact distance meter utilizing optical coherence tomography (OCT).

6. The inspection apparatus according to claim 4 or 5, characterized in that the plurality of sensor heads are arranged at predetermined angular intervals around the central axis of the object to be inspected.

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