Prism and visual inspection equipment

Abstract

To provide a prism used in a visual inspection device, which is capable of performing visual inspection of the inner and outer circumferential sides of a ring-shaped object to be inspected such as an O-ring, while shortening the inspection time of the object to be inspected in the visual inspection device. [Solution] A prism 3 is formed with a mounting surface 3c for a test object 2, and a first reflecting surface 3d and a second reflecting surface 3e that reflect light incident from the mounting surface 3c. The first reflecting surface 3d and the second reflecting surface 3e are arranged below the mounting surface 3c and reflect the light incident from the mounting surface 3c upward. The first reflecting surface 3d and the second reflecting surface 3e are annular, and the second reflecting surface e is arranged on the outer periphery of the first reflecting surface 3d and concentrically with the first reflecting surface 3d. The first reflecting surface 3d is an inclined surface that slopes downward as it moves radially outward, and the second reflecting surface 3e is an inclined surface that slopes upward as it moves radially outward.

Description

[Technical field]

[0001] The present invention relates to a prism used in an appearance inspection apparatus for inspecting the appearance of an object to be inspected, and also to an appearance inspection apparatus equipped with such a prism. [Background technology]

[0002] Conventionally, there is known an appearance inspection device for inspecting the appearance of an O-ring (see, for example, Patent Document 1). The appearance inspection device described in Patent Document 1 includes a transparent plate on which a mounting surface on which an O-ring is mounted is formed, a diffuse reflector disposed under the transparent plate, a rotating stage on which the transparent plate and the diffuse reflector are mounted, a ring-shaped inner illumination means for irradiating the inner upper surface of the O-ring with diffuse illumination light, an inner camera for photographing the inner upper surface of the O-ring, a ring-shaped outer illumination means for irradiating the outer upper surface of the O-ring with diffuse illumination light, and an outer camera for photographing the outer upper surface of the O-ring. In the appearance inspection device described in Patent Document 1, images of a portion of the O-ring are sequentially photographed by the inner camera and the outer camera while the O-ring is rotated by the rotating stage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-168305 A Summary of the Invention [Problem to be solved by the invention]

[0004] The appearance inspection device described in Patent Document 1 is capable of inspecting the appearance of the inner and outer circumference sides of an O-ring formed in a ring shape. However, when inspecting the appearance of an O-ring with the appearance inspection device described in Patent Document 1, it is necessary to rotate the O-ring on a rotating stage while sequentially taking images of parts of the O-ring with an inner camera and an outer camera, which takes time to inspect the appearance of the O-ring.

[0005] Therefore, an object of the present invention is to provide a prism for use in an appearance inspection device for performing an appearance inspection of an object to be inspected, which is capable of performing appearance inspection of the inner and outer circumferential sides of an annular object to be inspected, such as an O-ring, while shortening the inspection time of the object to be inspected in the appearance inspection device.Another object of the present invention is to provide an appearance inspection device equipped with such a prism. [Means for solving the problem]

[0006] In order to solve the above problems, the prism of the present invention is a prism used in a visual inspection device for visually inspecting an object to be inspected, and is formed with a planar mounting surface on which the object to be inspected can be mounted, and first and second reflecting surfaces which reflect light that enters the inside of the prism from the mounting surface, and where a direction perpendicular to the mounting surface is defined as the axial direction of the prism, a direction perpendicular to the axial direction is defined as the radial direction of the prism, one side of the axial direction is defined as a first direction side, and the side opposite to the first direction side is defined as a second direction side, the first and second reflecting surfaces are disposed on the second direction side of the mounting surface. Both reflect light that enters the inside of the prism from the mounting surface toward a first direction, and the shapes of the first and second reflecting surfaces when viewed from the axial direction are annular, the second reflecting surface is positioned on the outer periphery of the first reflecting surface and is positioned concentrically with the first reflecting surface when viewed from the axial direction, and the first reflecting surface is an inclined surface that slopes toward the second direction as it moves radially outward, and the second reflecting surface is an inclined surface that slopes toward the first direction as it moves radially outward.

[0007] In the prism of the present invention, the first and second reflecting surfaces, which reflect the light incident on the inside of the prism from the mounting surface on which the test object can be placed, toward the first direction, have an annular shape when viewed from the axial direction of the prism, and the second reflecting surface is disposed on the outer periphery of the first reflecting surface and is disposed concentrically with the first reflecting surface when viewed from the axial direction. Also, in the present invention, the first reflecting surface is an inclined surface that inclines toward the second direction as it moves toward the outside in the radial direction of the prism, and the second reflecting surface is an inclined surface that inclines toward the first direction as it moves toward the outside in the radial direction of the prism.

[0008] Therefore, in an appearance inspection device using the prism of the present invention, if a photographing mechanism is arranged on the first direction side of the prism, for example, when an annular inspection object such as an O-ring is inspected, it is possible to directly photograph the entire image of the first direction side of the inspection object placed directly on the mounting surface or via a transparent glass plate or the like by the photographing mechanism, and it is also possible to photograph the entire image of the inner circumference side and second direction side of the inspection object reflected on the first reflecting surface and the entire image of the outer circumference side and second direction side of the inspection object reflected on the second reflecting surface by the photographing mechanism. That is, in an appearance inspection device using the prism of the present invention, if a photographing mechanism is arranged on the first direction side of the prism, it is possible to photograph the entire image of the annular inspection object at once. Therefore, if the prism of the present invention is used in an appearance inspection device, it is possible to shorten the inspection time of the inspection object in the appearance inspection device, even if it is possible to perform appearance inspection of the inner circumference side and the outer circumference side of the annular inspection object such as an O-ring.

[0009] Furthermore, if the prism of the present invention is used in a visual inspection device, it is possible to capture an image of the second direction side of the object to be inspected without turning the object upside down, so that the inspection time of the object to be inspected in the visual inspection device can be further shortened. Furthermore, if the prism of the present invention is used in a visual inspection device, it is possible to capture an image of the outer peripheral surface of the object to be inspected reflected on the second reflecting surface, so that the object to be inspected can be inspected with high accuracy. Furthermore, if the prism of the present invention is used in a visual inspection device, it is possible to capture an image of the entire ring-shaped object to be inspected at once by arranging a photographing mechanism on the first direction side of the prism, so that the configuration of the visual inspection device can be simplified.

[0010] In the present invention, for example, in a longitudinal section of a prism including the axis of the prism, the first reflecting surface and the second reflecting surface are represented by two straight lines, and the inclination angle of the first reflecting surface relative to the radial direction is equal to the inclination angle of the second reflecting surface relative to the radial direction.

[0011] The prism of the present invention can be used in an appearance inspection device equipped with an imaging mechanism arranged on the first direction side of the prism. This appearance inspection device is capable of inspecting the inner and outer circumference sides of an annular object to be inspected, such as an O-ring, while shortening the inspection time for the object to be inspected.

[0012] In the present invention, for example, the object to be inspected is an O-ring, and the O-ring placed on the mounting surface is arranged concentrically with the first reflecting surface when viewed from the axial direction, and is positioned so as to overlap with the first reflecting surface or the second reflecting surface. Effect of the Invention

[0013] As described above, by using the prism of the present invention in a visual inspection device, it is possible to perform visual inspection of the inner and outer sides of a ring-shaped inspected object, such as an O-ring, and also to shorten the inspection time of the inspected object in the visual inspection device. [Brief description of the drawings]

[0014] [Figure 1] (A) is a schematic diagram for explaining the configuration of a visual inspection apparatus according to an embodiment of the present invention, (B) is a plan view of the prism shown in (A), (C) is a cross-sectional view of the inspected object and the prism shown in (A), and (D) is a bottom view of the prism shown in (A). [Diagram 2] FIG. 2 is a diagram for explaining the configuration of a prism shown in FIG. [Diagram 3] 2 is a diagram for explaining an image captured by the imaging mechanism shown in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0016] (Configuration of visual inspection device and prism) Fig. 1(A) is a schematic diagram for explaining the configuration of an appearance inspection device 1 according to an embodiment of the present invention, Fig. 1(B) is a plan view of a prism 3 shown in Fig. 1(A), Fig. 1(C) is a cross-sectional view of an O-ring 2 and a prism 3 shown in Fig. 1(A), and Fig. 1(D) is a bottom view of the prism 3 shown in Fig. 1(A). Fig. 2 is a diagram for explaining the configuration of the prism 3 shown in Fig. 1. Fig. 3 is a diagram for explaining an image captured by a camera 4 shown in Fig. 1.

[0017] The appearance inspection device 1 is a device for performing an appearance inspection of an object 2 to be inspected. The object 2 to be inspected in this embodiment is an O-ring formed in a ring shape. Therefore, hereinafter, the object 2 to be inspected is referred to as an "O-ring 2". The O-ring 2 is made of rubber. The shape of the O-ring 2 when no external force is applied is annular. The appearance inspection device 1 inspects the surface of the O-ring 2 for scratches and distortions, and for the presence or absence of foreign matter attached to the surface of the O-ring 2. The appearance inspection device 1 includes a prism 3. That is, the prism 3 is used in the appearance inspection device 1. In addition to the prism 3, the appearance inspection device 1 includes a camera 4 as a photographing mechanism arranged above the prism 3. The appearance inspection device 1 in this embodiment includes one camera 4.

[0018] The camera 4 is disposed directly above the O-ring 2. The camera 4 is installed so that the optical axis of the camera 4 coincides with the up-down direction (vertical direction, Z direction in FIG. 1(A)). The optical axis of the camera 4 passes through, for example, the axis of the O-ring 2 placed on a mounting surface 3c (described later) formed on the prism 3. In the up-down direction, an illumination mechanism (not shown) for shining light onto the O-ring 2 is disposed between the O-ring 2 and the camera 4. That is, the appearance inspection device 1 is equipped with an illumination mechanism. The illumination mechanism is a bright field illumination mechanism that shines light directly onto the O-ring 2 from directly above. The illumination mechanism is, for example, a ring illumination formed in a ring shape, and is disposed at a position that does not interfere with the imaging of the camera 4.

[0019] Prism 3 is formed of, for example, transparent glass or resin. Prism 3 is formed in a flat, approximately truncated cone shape with its axis extending in the up-down direction (vertical direction, Z direction in FIG. 1(A)) and with a short axial length. Specifically, prism 3 is composed of a flat, cylindrical (disk-shaped) portion constituting about half of the upper side of prism 3, and a flat, truncated cone portion constituting about half of the lower side of prism 3 and having a gradually smaller outer diameter toward the bottom. The direction perpendicular to the up-down direction (i.e., the axial direction of prism 3) is the radial direction of prism 3.

[0020] The prism 3 is attached to a support member (not shown). A through hole 3a is formed in the center of the prism 3, penetrating the prism 3 in the vertical direction. A recess 3b is formed on the lower surface of the prism 3, recessed toward the upper side. The recess 3b is formed in the center of the lower surface of the prism 3. The recess 3b is formed in a truncated cone shape whose outer diameter gradually decreases toward the upper side. The upper end of the recess 3b is connected to the lower end of the through hole 3a.

[0021] The prism 3 is also formed with a planar mounting surface 3c on which the O-ring 2 can be mounted, and a first reflecting surface 3d and a second reflecting surface 3e that reflect light incident from the mounting surface 3c into the inside of the prism 3. The mounting surface 3c is a plane perpendicular to the up-down direction. That is, the up-down direction, which is the axial direction of the prism 3, is perpendicular to the mounting surface 3a. The upper side (Z1 direction side in FIG. 1(A)) of this embodiment is the first direction side, which is one side of the axial direction of the prism 3, and the lower side (Z2 direction side in FIG. 1(A)) is the second direction side, which is the other side of the axial direction of the prism 3.

[0022] The mounting surface 3c constitutes the upper surface of the prism 3 and faces upward. The mounting surface 3c is formed in a circular shape. In this embodiment, the O-ring 2 is directly mounted on the mounting surface 3c. The first reflecting surface 3d and the second reflecting surface 3e are disposed below the mounting surface 3c. The first reflecting surface 3d and the second reflecting surface 3e reflect the light incident from the mounting surface 3c into the inside of the prism 3 to the upper side. The first reflecting surface 3d and the second reflecting surface 3e are shaped like an annular ring when viewed from the top-bottom direction. The second reflecting surface 3e is disposed on the outer periphery side of the first reflecting surface 3d and is disposed concentrically with the first reflecting surface 3d when viewed from the top-bottom direction, and surrounds the first reflecting surface 3d when viewed from the top-bottom direction. The first reflecting surface 3d and the second reflecting surface 3e are disposed concentrically with the through hole 3a when viewed from the top-bottom direction.

[0023] The first reflecting surface 3d constitutes the side surface of the recess 3b formed in a truncated cone shape. The first reflecting surface 3d is an inclined surface that slopes downward as it approaches the outside in the radial direction of the prism 3. When viewed from the top-bottom direction, the first reflecting surface 3d surrounds the through hole 3a. The second reflecting surface 3e constitutes the side surface of the lower part of the prism 3 formed in a truncated cone shape. The second reflecting surface 3e is an inclined surface that slopes upward as it approaches the outside in the radial direction of the prism 3.

[0024] The inner diameter of the second reflecting surface 3e formed in a circular ring shape is slightly larger than the outer diameter of the first reflecting surface 3d formed in a circular ring shape. For example, the outer diameter of the first reflecting surface 3d is about 21 mm, and the inner diameter of the second reflecting surface 3e is about 22 mm. The outer diameter of the second reflecting surface 3e is about 50 mm. Between the first reflecting surface 3d and the second reflecting surface 3e in the radial direction of the prism 3, a circular ring surface 3f, which is a circular ring-shaped flat surface perpendicular to the up-down direction, is formed. The width of the circular ring surface 3f in the radial direction of the prism 3 is narrow.

[0025] As shown in Fig. 1(C) etc., in a vertical cross section of the prism 3 including the axis of the prism 3, the first reflecting surface 3d and the second reflecting surface 3e are represented by two straight lines. In this embodiment, the inclination angle θ1 of the first reflecting surface 3d with respect to the radial direction of the prism 3 (see Fig. 2(A)) is equal to the inclination angle θ2 of the second reflecting surface 3e with respect to the radial direction of the prism 3 (see Fig. 2(A)). The inclination angles θ1 and θ2 are, for example, about 15°. The shape of the lower surface of the vertical cross section of the prism 3 is W-shaped.

[0026] The outer diameter D (see FIG. 1(C)) of the O-ring 2 inspected by the visual inspection device 1 is, for example, 30 mm or 20 mm. The O-ring 2 mounted on the mounting surface 3c is arranged concentrically with the first reflecting surface 3d when viewed from the top-bottom direction. That is, the O-ring 2 is mounted on the mounting surface 3c so as to be arranged concentrically with the through-hole 3a, the first reflecting surface 3d, and the second reflecting surface 3e when viewed from the top-bottom direction. For example, when the outer diameter of the O-ring 2 is 30 mm, the O-ring 2 mounted on the mounting surface 3c is arranged at a position overlapping with the second reflecting surface 3e when viewed from the top-bottom direction (see FIG. 2(A)), and when the outer diameter of the O-ring 2 is 20 mm, the O-ring 2 mounted on the mounting surface 3c is arranged at a position overlapping with the first reflecting surface 3d when viewed from the top-bottom direction (see FIG. 2(B)).

[0027] 2, the first reflecting surface 3d reflects light that is emitted from the illumination mechanism and enters the prism 3 from above, toward the inner circumferential and lower parts of the O-ring 2, and reflects the light reflected by the O-ring 2 upward toward the camera 4. The second reflecting surface 3e reflects light that is emitted from the illumination mechanism and enters the prism 3 from above, toward the outer circumferential and lower parts of the O-ring 2, and reflects the light reflected by the O-ring 2 upward toward the camera 4.

[0028] The light reflected by the O-ring 2 and then further reflected by the first reflecting surface 3d toward the camera 4 passes through the inner circumferential side of the O-ring 2. The inclination angle θ1 of the first reflecting surface 3d is set so that the light reflected by the O-ring 2 and then further reflected by the first reflecting surface 3d toward the camera 4 is not blocked by the O-ring 2. The light reflected by the O-ring 2 and then further reflected by the second reflecting surface 3e toward the camera 4 passes through the outer circumferential side of the O-ring 2. The inclination angle θ2 of the second reflecting surface 3e is set so that the light reflected by the O-ring 2 and then further reflected by the second reflecting surface 3e toward the camera 4 is not blocked by the O-ring 2.

[0029] For example, when the appearance inspection device 1 is performing an appearance inspection of an O-ring 2 having an outer diameter of 30 mm, the camera 4 directly captures an image P1 of the entire upper portion of the O-ring 2, and also captures an image P2 of the entire inner and lower portion of the O-ring 2 reflected on the first reflecting surface 3d, and an image P3 of the entire outer and lower portion of the O-ring 2 reflected on the second reflecting surface 3e (see FIG. 3). That is, when the appearance inspection of the O-ring 2 is performed by the appearance inspection device 1, the camera 4 captures an image of the entire O-ring 2 at once. The images P1 to P3 are annular images and are arranged concentrically. Moreover, the image P2 is arranged on the inner side of the image P1, and the image P3 is arranged on the outer side of the image P1.

[0030] Similarly, when the appearance inspection device 1 is used to inspect the appearance of an O-ring 2 having an outer diameter of 20 mm, the camera 4 directly captures an image of the entire upper portion of the O-ring 2, and also captures an image of the entire inner and lower portion of the O-ring 2 reflected on the first reflecting surface 3d and an image of the entire outer and lower portion of the O-ring 2 reflected on the second reflecting surface 3e. A personal computer (PC) is electrically connected to the camera 4. The images captured by the camera 4 are transmitted to the PC. Based on the images captured by the camera 4, the PC determines whether or not there are scratches or distortions on the surface of the O-ring 2, and whether or not there is any foreign matter attached to the surface of the O-ring 2.

[0031] (Main effects of this form) As described above, in this embodiment, the first reflecting surface 3d and the second reflecting surface 3e that reflect the light incident from the mounting surface 3c into the inside of the prism 3 upward have a circular shape when viewed from the top-bottom direction, and the second reflecting surface 3e is disposed on the outer periphery side of the first reflecting surface 3d and is disposed concentrically with the first reflecting surface 3d when viewed from the top-bottom direction. Also, in this embodiment, the first reflecting surface 3d is an inclined surface that slopes downward as it approaches the outside in the radial direction of the prism 3, and the second reflecting surface 3e is an inclined surface that slopes upward as it approaches the outside in the radial direction of the prism 3.

[0032] Therefore, in this embodiment, as described above, an image P1 of the entire upper portion of the O-ring 2 is directly captured by the camera 4, and an image P2 of the entire inner and lower portion of the O-ring 2 reflected on the first reflecting surface 3d and an image P3 of the entire outer and lower portion of the O-ring 2 reflected on the second reflecting surface 3e are also captured by the camera 4. That is, in this embodiment, an image of the entire O-ring 2 is captured at once by the camera 4. Therefore, in this embodiment, even if it is possible to perform an appearance inspection of the inner and outer sides of the O-ring 2 formed in a ring shape, it is possible to shorten the inspection time of the O-ring 2 in the appearance inspection device 1.

[0033] In addition, in this embodiment, it is possible to use camera 4 to capture an image of the lower portion of O-ring 2 without turning O-ring 2 upside down, so that the inspection time of O-ring 2 in visual inspection device 1 can be further shortened. In this embodiment, it is possible to use camera 4 to capture an image of the outer peripheral surface of O-ring 2 reflected on second reflecting surface 3e, so that O-ring 2 can be inspected with high accuracy. Furthermore, in this embodiment, by disposing camera 4 above prism 3, it is possible to capture an image of the entire O-ring 2 formed in a ring shape at once, so that the configuration of visual inspection device 1 can be simplified.

[0034] (Other embodiments) In the above embodiment, the O-ring 2 does not have to be placed directly on the mounting surface 3c. For example, the O-ring 2 placed on a transparent glass plate formed in a thin, flat shape may be placed on the mounting surface 3c together with the glass plate. That is, the O-ring 2 may be placed on the mounting surface 3c via a glass plate or the like. In this case, by placing the O-ring 2 on each of the multiple glass plates in advance while the appearance inspection device 1 is offline, it becomes possible to easily replace the O-ring 2 set in the appearance inspection device 1.

[0035] In the above embodiment, the first reflecting surface 3d is represented by two straight lines in the longitudinal cross section of the prism 3, but the first reflecting surface 3d may be formed so that the first reflecting surface 3d is represented by two curved lines in the longitudinal cross section of the prism 3. That is, the first reflecting surface 3d may be formed as a convex curved surface that bulges toward the inside and the lower side in the radial direction of the prism 3, or may be formed as a concave curved surface that recesses toward the outside and the upper side in the radial direction of the prism 3. Even in this case, the first reflecting surface 3d is an inclined surface that inclines downward as it approaches the outside in the radial direction of the prism 3. In this case, the size of the image P2 captured by the camera 4 can be changed.

[0036] Similarly, the second reflecting surface 3e may be formed so that it is represented by two curved lines in a longitudinal cross-sectional view of the prism 3. That is, the second reflecting surface 3e may be formed as a convex curved surface that bulges outward and downward in the radial direction of the prism 3, or may be formed as a concave curved surface that recesses inward and upward in the radial direction of the prism 3. Even in this case, the second reflecting surface 3e is an inclined surface that slopes upward as it approaches the radial outside of the prism 3. In this case, it is also possible to change the size of the image P3 captured by the camera 4.

[0037] In the above-mentioned embodiment, the prism 3 may not have a toric surface 3f. That is, the inner diameter of the second reflecting surface 3e and the outer diameter of the first reflecting surface 3d may be equal. In the above-mentioned embodiment, the inclination angle θ1 of the first reflecting surface 3d and the inclination angle θ2 of the second reflecting surface 3e may be different. In the above-mentioned embodiment, the inspected object 2, the appearance of which is inspected by the appearance inspection device 1, may be an annular sealing member such as a packing or gasket other than an O-ring, or may be an annular member other than a sealing member. In addition, the inspected object 2 may be formed in a ring shape other than a ring shape, or may not be formed in a ring shape. For example, the inspected object 2 may be formed in a C-shape. In the above-mentioned embodiment, the illumination mechanism for irradiating the O-ring 2 with light may be a dark-field illumination mechanism. [Explanation of symbols]

[0038] 1. Visual inspection equipment 2 O-ring (test object) 3. Prism 3c Placement surface 3d 1st reflective surface 3e 2nd reflective surface 4. Camera (filming mechanism) Z Prism axis direction Z1 1st direction side Z2 2nd direction side θ1 Inclination angle of the first reflecting surface θ2 Inclination angle of the second reflecting surface

Claims

1. A prism used in a visual inspection apparatus for performing a visual inspection of an object to be inspected, a flat mounting surface on which the test object can be mounted, and a first reflecting surface and a second reflecting surface that reflect light incident from the mounting surface into the inside of the prism are formed; A direction perpendicular to the mounting surface is defined as an axial direction of the prism, a direction perpendicular to the axial direction is defined as a radial direction of the prism, one side of the axial direction is defined as a first direction side, and the side opposite to the first direction side is defined as a second direction side. the first reflecting surface and the second reflecting surface are disposed on the second direction side of the mounting surface, and reflect light incident from the mounting surface into an inside of the prism toward the first direction, a shape of the first reflecting surface and a shape of the second reflecting surface when viewed in the axial direction are annular, the second reflecting surface is disposed on an outer circumferential side of the first reflecting surface and is disposed concentrically with the first reflecting surface when viewed from the axial direction, The first reflecting surface is an inclined surface that is inclined toward the second direction as it extends outward in the radial direction, The prism is characterized in that the second reflecting surface is an inclined surface that is inclined toward the first direction as it extends radially outward.

2. In a vertical cross section of the prism including an axis of the prism, the first reflecting surface and the second reflecting surface are represented by two straight lines, 2. The prism according to claim 1, wherein an inclination angle of said first reflecting surface with respect to said radial direction is equal to an inclination angle of said second reflecting surface with respect to said radial direction.

3. 3. An appearance inspection apparatus comprising: the prism according to claim 1; and an imaging mechanism disposed on the first direction side of the prism.

4. the test object is an O-ring, An appearance inspection apparatus as described in claim 3, characterized in that the O-ring placed on the mounting surface is arranged concentrically with the first reflecting surface when viewed from the axial direction, and is arranged in a position overlapping the first reflecting surface or the second reflecting surface.

Images