Inspection apparatus

Abstract

To provide an inspection device capable of inspecting accurately by making a flaw formed on a surface of an inspection object conspicuous.SOLUTION: An inspection device 1 includes an illumination device 3 in which a plurality of illuminations 32 are arranged on a base 31 configured in a planar shape, a camera 4 that receives reflected light of light emitted from the illumination device 3, and an inspection unit 5 that inspects quality of a defective part formed on a surface of an inspection target 6 on the basis of an image acquired by the camera 4. A partition plate 34 that partitions and shields the illumination 32 for each block is provided in the illumination device 3 configured in a flat shape, and the inspection unit 5 switches the illumination 32 for each of blocks B1 to B4 partitioned by the partition plate 34, acquires an image, and inspects SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an inspection device that can inspect defects such as scratches and irregularities formed on the surface of an object, and more particularly to an inspection device that can clearly detect and inspect defective areas. [Background technology]

[0002] Generally, when inspecting for defects such as scratches formed on the surface of an object, the object is irradiated with light, the reflected light is received by a camera, and the image obtained by the received light is analyzed to determine whether or not the object has any defects.

[0003] When inspecting defects formed on such surfaces, if light is irradiated onto a planar inspection object, the inspection object appears bright in the specular reflection areas (hereinafter referred to as "reflective areas") of the inspection object, and scratches present in the reflective areas appear dark due to the change in the reflection angle caused by the scratches. Conversely, in the non-reflective areas where the reflected light is not received by the camera, the background appears dark and the scratches appear bright due to the change in the reflection angle of light caused by the scratches. Furthermore, when inspecting the same scratch in these reflective and non-reflective areas, the scratches may be detected as having different areas depending on the condition of each scratch.

[0004] Incidentally, when irradiating the inspection object with light in this manner, depending on the direction of the flaw, the flaw may not be noticeable due to differences in the direction of reflection.

[0005] For this reason, a method has been proposed in which the illumination of a dome-shaped illumination device is switched to irradiate light from multiple angles to enable inspection (Patent Document 1), and a method in which the illumination of a ring-shaped illumination device is switched to irradiate light from multiple angles to enable inspection (Patent Document 2).With these methods, scratches can be detected by irradiating light onto them from various directions. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-131365 [Patent Document 2] Unexamined Japanese Patent Publication No. 2022-153735 Summary of the Invention [Problem to be solved by the invention]

[0007] However, even this method has the following problems.

[0008] In other words, the inspection device described above can detect dark scratches by shining light from various directions onto scratches in the reflective area, but it can sometimes be difficult to accurately grasp the condition of the scratch just by looking at the condition of the scratch in such a bright reflective area.

[0009] Therefore, it is possible to detect bright scratches by receiving reflected light from scratches that exist in dark non-reflective areas outside the reflective area, but at the boundary between the reflective area and the non-reflective area, light from the reflective area leaks into the non-reflective area, making it impossible to increase the contrast of scratches in the area near the boundary between the reflective area and the non-reflective area.

[0010] Therefore, the present invention has been made with an eye on the above-mentioned problems, and aims to provide an inspection device that makes scratches formed on the surface of the object to be inspected more noticeable, enabling accurate inspection. [Means for solving the problem]

[0011] That is, in order to solve the above-mentioned problems, the present invention provides an inspection device comprising an illumination device in which a plurality of illumination devices are arranged on a planar base, a camera that receives reflected light from the light irradiated from the illumination device, and an inspection unit that inspects the quality of defective areas formed on the surface of an object to be inspected based on images acquired by the camera, wherein the planar illumination device is provided with partition plates that separate the illumination devices into blocks and block light, and the inspection unit switches the illumination devices for each block separated by the partition plates to acquire images and perform inspection.

[0012] With this configuration, the partition plate can clearly separate the bright reflective area from the dark non-reflective area, and inspection can be performed in the reflective area while increasing the contrast of defective areas in the reflective and non-reflective areas, making scratches more noticeable for inspection.

[0013] In addition, in such an invention, the camera simultaneously acquires images of both the reflective area that receives reflected light from the lighting device and the non-reflective area outside the reflective area, and the inspection unit inspects for defective areas present in the reflective area and also inspects for defective areas present in the non-reflective area.

[0014] In this way, it becomes possible to inspect not only the reflective area as in the conventional method, but also the state of defective portions in the non-reflective area at the same time.

[0015] Furthermore, the camera is provided above a circular opening provided in the center of the base of the lighting device, and a cylindrical portion having a cylindrical shape is provided in the circular opening so as to protrude toward the inspection target portion.

[0016] This configuration can limit the light that enters the circular opening, and can provide a clear contrast between reflective and non-reflective areas in the image captured by the camera.

[0017] Furthermore, if the camera is positioned above a circular opening provided in the center of the base of the lighting device and a cylindrically shaped portion is provided in the circular opening so as to protrude toward the inspection target portion, the end of the partition plate is attached and fixed to the side of the cylindrical portion.

[0018] With this configuration, the partition plate can be firmly fixed, and the lighting can be enclosed by the partition plate and the cylindrical portion.

[0019] Furthermore, a plurality of the partition plates are provided in the intersecting direction.

[0020] With this configuration, for example, by dividing a rectangular lighting device into four equal parts around the center and irradiating light from each direction, it is possible to form reflective and non-reflective areas around defective areas, enabling accurate inspection under a variety of conditions.

[0021] The cylindrical portion is made of a black non-reflective material that does not reflect light.

[0022] This configuration prevents reflected light from entering the camera, making the contrast clearer. [Effects of the Invention]

[0023] According to the present invention, an inspection device comprises an illumination device having a plurality of illumination devices arranged on a planar base, a camera that receives reflected light from the light irradiated from the illumination device, and an inspection unit that inspects the quality of defective areas formed on the surface of an object to be inspected based on images acquired by the camera.The planar illumination device is provided with a partition plate that divides the illumination into blocks and blocks light, and the inspection unit switches the illumination for each block separated by the partition plate and acquires images for inspection.Therefore, the partition plate makes it possible to clearly separate bright reflective areas from dark non-reflective areas, and inspection can be performed in the reflective areas while increasing the contrast of defective areas in the reflective and non-reflective areas, making scratches more noticeable for inspection. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a schematic side view of an inspection device according to an embodiment of the present invention; [Figure 2] 1 is a bottom view of the lighting device in the same configuration. [Figure 3] FIG. 10 shows an image captured by a camera in the same configuration. [Figure 4] A diagram showing an image in which the lighting is switched without a partition plate installed. [Figure 5] FIG. 10 is a diagram showing an image in which the illumination is switched without providing a cylindrical portion. [Figure 6] A diagram showing the inspection flow in the same form. [Figure 7] FIG. 10 is a schematic diagram showing an inspection device according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0026] The inspection device 1 of this embodiment is designed to inspect the surface of an object under inspection 6 for defects such as scratches and irregularities. As shown in FIG. 1 , the inspection device 1 includes an illumination device 3 that irradiates light onto the object under inspection 6 placed on a mounting table 2, a camera 4 that receives reflected light from the light irradiated by the illumination device 3, and an inspection unit 5 that inspects the object under inspection 6 for defects using images captured by the camera 4. Characteristically, the illumination device 3 includes a plurality of luminaires 32 mounted on a base 31, which are separated by partition plates 34 to form blocks. When irradiating the object under inspection 6 with light, the partition plates 34 clearly define the boundaries between illuminated and unilluminated blocks. This configuration clearly defines the brightness of the reflective area 71 and the non-reflective area 72, making defects such as scratches more clearly visible. The inspection device 1 of this embodiment will be described in detail below. In this embodiment, the object under inspection 6 is assumed to be a planar object placed on a planar mounting table 2.

[0027] First, the lighting device 3 is configured by arranging multiple luminaires 32, such as LEDs, on the surface of a substantially rectangular base 31. The luminaires 32 are evenly spaced along the surface of the base 31 and are configured to irradiate light downward from each block with uniform illuminance. The base 31 is provided with side walls 33 around its periphery to prevent light from leaking outward. Further, partition plates 34 are provided inward from the side walls 33, allowing each luminaire 32 to form a block. The base 31 is further provided with a circular opening 35 in the center to allow light to be received by the camera 4. A black cylindrical portion 36 is attached below the circular opening 35. The partition plate 34 is attached by attaching one end to the side wall 33 and the other end to the cylindrical portion 36, thereby forming a block surrounded by the partition plate 34, the cylindrical portion 36, and the side wall 33. In this example, two partition plates 34 are provided in the X direction from the central cylindrical portion 36 and two partition plates 34 are provided in the Y direction from the central cylindrical portion 36 on the rectangular base 31, forming four small rectangular blocks. In this case, if the blocks are designated B1, B2, B3, and B4 along the rotational direction, it is possible to switch between illuminating only B1 and B2, illuminating only B2 and B3, illuminating only B3 and B4, and illuminating only B4 and B1, and to light all B1 to B4.

[0028] The camera 4 receives light that is reflected from the inspection object 6 out of the light emitted from the lighting device 3, and captures an image with the field of view covering the area of ​​the cylindrical portion 36. In this case, when capturing an image in which two adjacent blocks B1 to B4 are sequentially lit, half of the circular field of view will be a bright reflective area 71 and the other half will be a dark non-reflective area 72, as shown in Figure 〇.

[0029] The inspection unit 5 inspects the image acquired by the camera 4 for defects such as scratches, using various techniques. Specifically, for example, the inspection unit 5 detects whether there are any pixels in the reflective region 71 that are darker than a predetermined reference brightness value. If there are multiple adjacent pixels, the pixels are grouped together, and if the area of ​​the grouped region is equal to or greater than a predetermined value, the inspection unit 5 determines that the region is defective. Conversely, the inspection unit 5 detects whether there are any pixels in the non-reflective region 72 that are brighter than a predetermined reference brightness value. If there are multiple adjacent pixels, the pixels are grouped together, and if the area of ​​the grouped region is equal to or greater than a predetermined value, the inspection unit 5 determines that the region is defective. Note that when the reflective region 71 and the non-reflective region 72 are inspected separately, the contrast difference becomes unclear at the boundary between the reflective region 71 and the non-reflective region 72, making accurate inspection difficult. Therefore, the illumination 32 is rotated between B1 and B2, B2 and B3, B3 and B4, and B4 and B1 for inspection. In this way, there are no boundaries, so that defects such as scratches can be located in the reflective area 71 and the non-reflective area 72 for all areas and can be inspected.

[0030] Next, we will compare and explain the image taken by camera 4 when partition plate 34 and cylindrical portion 36 are installed (Figure 3) with the image taken by camera 4 when partition plate 34 and cylindrical portion 36 are not installed (Figure 4).

[0031] 3 and 4 show the state when an undamaged plate-like object with a mirror surface is used as the inspection object 6, and light is irradiated onto it by sequentially switching half of the light in the rotation direction between B1 and B2, B2 and B3, B3 and B4, and B4 and B1, without the partition plate 34 or cylindrical portion 36. As can be seen from Fig. 4, when the partition plate 34 or cylindrical portion 36 is not provided, light leaks into the non-reflective area 72, and when an attempt is made to inspect the non-reflective area 72, it is not possible to increase the contrast.

[0032] In contrast to this, when a partition plate 34 or a cylindrical portion 36 is provided as shown in Figure 3, the boundary between the reflective area 71 and the non-reflective area 72 becomes clear, and when inspection is performed in the non-reflective area 72, the contrast of the flaw can be increased and the inspection can be performed.

[0033] Next, a comparative example will be shown of a state where the cylindrical portion 36 is not attached to the circular opening 35 of the lighting device 3 (FIG. 5) and a state where the cylindrical portion 36 is attached (FIG. 3).

[0034] As shown in Fig. ◯, if the cylindrical portion 36 is not attached to the circular opening 35, light enters the edge of the circular opening 35, making the area around the edge of the circular opening 35 bright. As a result, scratches and the like present at that position cannot be inspected as an inspection in the non-reflective area 72.

[0035] In contrast, as shown in FIG. 3, when a black cylindrical portion 36 is attached to the circular opening 35, light does not enter the edge of the circular opening 35, and inspection can be performed in the reflective area 71 and the non-reflective area 72 even near the edge of the circular opening 35.

[0036] By providing the partition plate 34 and the cylindrical portion 36 in this way, the field of view of the camera 4 can be clearly divided into a reflective area 71 and a non-reflective area 72.

[0037] Next, a method for inspecting the presence or absence of defective portions formed on the surface of the inspection object 6 using the inspection device 1 configured as above will be described with reference to the flowchart of FIG.

[0038] First, when inspecting the inspection object 6, the inspection object 6 is placed on the placement table 2.

[0039] First, all the lights 32 from B1 to B4 are turned on (step S1), and all the regions are inspected as reflective regions (step S2), and the results are output (step S3).

[0040] Next, among the four blocks separated by the partitions 34, the lights 32 in B1 and B2 are turned on (step S4).

[0041] 3, light emitted from B1 and B2 is irradiated onto the inspection object 6 with the side light blocked by the partition plate 34, and the specularly reflected light is acquired by the camera 4. At this time, the light reflected from the inspection object 6 hits the inner surface of the cylindrical portion 36, but because the cylindrical portion 36 is configured to be black, there is no reflection from there, and only the light directly reflected from the inspection object 6 enters the camera 4. Then, by receiving the reflected light in this way, half of the circular light receiving area becomes a bright reflective area 71, and the other half becomes a dark non-reflective area 72.

[0042] Then, with the area divided into the reflective area 71 and the non-reflective area 72 in this way, each area is inspected for defects (step S5), and if there are any defective pixels with a predetermined area or more, information indicating that they are "defective" and their location are output (step S6).

[0043] Next, when the inspection based on irradiation from B1 and B2 is completed, only B2 and B3 are irradiated (step S7), and the reflective area 71 and the non-reflective area 72 are rotated in the rotation direction for inspection and output (steps S8 and S9).

[0044] Similarly, irradiation of only B3 and B4 (step S11), inspection and output (steps S12 and S13), and irradiation of only B4 and B1 (step S13), inspection and output (steps S14 and S15) are performed.

[0045] According to the above embodiment, the inspection device 1 includes an illumination device 3 having a plurality of illumination devices 32 such as LEDs arranged on a flat base 31, a camera 4 that receives reflected light from the light irradiated from the illumination device 3, and an inspection unit 5 that inspects the quality of defective areas formed on the surface of the object to be inspected 6 based on images acquired by the camera 4. The planar illumination device 3 is provided with partition plates 34 that separate the illumination devices 32 into blocks B1 to B4 and block light, and the inspection unit 5 switches the illumination devices 32 for each block B1 to B4 separated by the partition plates 34 to acquire images for inspection. Therefore, the partition plates 34 can clearly separate the bright reflective area 71 and the dark non-reflective area 72, and inspection can be performed in the reflective area 71 while increasing the contrast of defective areas in the reflective area 71 and the non-reflective area 72, making it possible to make scratches stand out and inspect them.

[0046] The present invention is not limited to the above-described embodiment, but can be implemented in various forms.

[0047] For example, in the above embodiment, the partition plates 34 are provided at right angles to the X and Y directions for inspection, but the partition plates 34 may be provided at predetermined angles other than right angles for inspection. In this case, however, it is preferable to perform inspection while shifting the position of the illumination 32 so that the boundary between the reflective area 71 and the non-reflective area 72 is shifted sequentially.

[0048] In the above embodiment, the inspection object 6 is placed on the mounting table 2 for inspection, but a movable mounting table 2 such as a conveyor may be used as the mounting table 2. When inspection in a predetermined inspection area is completed, the mounting table 2 may be driven to acquire an image of the next inspection area and perform inspection.

[0049] Furthermore, in the above embodiment, the partition plate 34 is provided, but the partition plate 34 may be made of a material other than a plate, as long as it blocks light from each block.

[0050] Furthermore, as shown in FIG. 7, even when the illumination device 3 installed between the inspection object 6 and the camera 4 is a coaxial illumination device using a half mirror 37 that directs light directly onto the inspection object 6, inspection can be performed using an illumination device 3 having a similar partition plate 34. [Explanation of symbols]

[0051] 1. Inspection equipment 2. Mounting table 3. Lighting equipment 31...Base 32. Lighting 33...side wall 34 Divider 35...Circular opening 36 Cylindrical part 37. Half mirror 4. Camera 5. Inspection Department 6. Inspection object 71...reflection area 72...Non-reflective area

Claims

1. a lighting device in which a plurality of lights are arranged on a flat base; a camera that receives reflected light from the light emitted from the lighting device; an inspection unit that inspects whether a defective portion formed on the surface of the inspection object is good or bad based on the image acquired by the camera; In an inspection device comprising: a partition plate for dividing the illumination into blocks and blocking light is provided in the planar illumination device; The inspection device in which the inspection unit switches the illumination for each block separated by the partition plate to acquire images and perform inspection.

2. the camera simultaneously captures images of both a reflective area that receives reflected light of light irradiated from the lighting device and a non-reflective area outside the reflective area, 2. The inspection device according to claim 1, wherein the inspection unit inspects for defective portions present in the reflective area and also inspects for defective portions present in the non-reflective area.

3. the camera is provided above a circular opening provided in the center of a base of the lighting device; 2. The inspection device according to claim 1, wherein a cylindrical portion formed in a cylindrical shape is provided in the circular opening so as to protrude toward the inspection object portion.

4. the camera is provided above a circular opening provided in the center of a base of the lighting device; a cylindrical portion formed in a cylindrical shape is provided in the circular opening portion so as to protrude toward the inspection object portion, 2. The inspection device according to claim 1, wherein an end of the partition plate is attached and fixed to a side surface of the cylindrical portion.

5. 2. The inspection device according to claim 1, wherein a plurality of the partition plates are provided in intersecting directions.

6. the camera is provided above a circular opening provided in the center of a base of the lighting device; a cylindrical portion formed in a cylindrical shape is provided in the circular opening portion so as to protrude toward the inspection object portion, 2. The inspection device according to claim 1, wherein the cylindrical portion is made of a black non-reflective material.

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