JP2559763Y2 - Lighting equipment for inspection - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device suitable for use in inspecting the appearance of medicines, foods, machine parts, and the like.

[Prior art]

FIG. 4 shows a conventional lighting device for visual inspection. As shown in FIG. 1, a conventional lighting device includes a light source (11) for illuminating an inspection object (m) at an inspection position, and a diffusion transmitting member provided between the light source (11) and the inspection object (m). (12), wherein the diffuse transmission member (12) is configured to cover the inspection object (m), and has a through hole (13) for inspection in a part thereof. I have.

The diffusion transmitting member (12) is a translucent member and has a property of scattering transmitted light. Therefore, the light emitted from the light source (11) is diffused and scattered by passing through the diffusion transmitting member (12), reaches the inspection object (m), and uniformly illuminates it from all directions. Then, the object to be inspected (m) is passed through a through hole (13) provided in the diffusion transmission member (12) by a camera or the like.
An image is taken for inspection.

[0004]

However, according to the above-mentioned conventional lighting device, there is no problem if the surface of the inspection object (m) has no gloss. If so, there are problems described below.

That is, as described above, in order to image the inspection object (m) from the through hole (13) provided in the diffusion transmitting member (12), the inspection object (m) is passed through the through hole (13).
Cannot be illuminated, but the inspection object (m)
When the surface has no gloss, the light diffusely radiated through the diffuse transmission member (12) reaches the surface of the inspection object (m) uniformly and is also irregularly reflected on the surface. The surface of the inspection object (m) exhibits uniform brightness,
It is not affected by the through hole (13). On the other hand, the inspection object (m)
If the surface has a glossy surface, the light received by the surface is totally reflected.
The back surface of 2) is directly copied by a mirror.
That is, an image in which the portion of the through hole (13) is a dark portion and the other portion is a bright portion.

More specifically, an image obtained by image pickup is as shown in FIG. 5A, and the brightness signal of the line 1 in FIG. 5B is as shown in FIG. In the drawing, (7) indicates a defective portion, but the portion is usually dark.

Normally, a signal obtained by differentiating the brightness signal is judged based on a predetermined threshold value, and a signal exceeding the threshold value is determined to be defective.
As shown in the figure, the brightness signal drops at the portion corresponding to the through hole (3) and the portion corresponding to the defective portion (7), and the differentiated signal shown in FIG. Peak values are respectively generated in portions corresponding to both. If both of the peak values exceed a predetermined threshold value, it is determined that the device is defective. In the case of this example, the determination is correct because there is really a defective portion. However, even when there is no defective portion, it can be determined to be defective due to the dark portion corresponding to the through hole (3). Means that it is a problem.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a lighting device capable of accurately inspecting an object (m) to be inspected even if the surface of the object (m) has gloss.

[0009]

According to a first aspect of the present invention, there is provided a light source for illuminating an inspection object at an inspection position, and a diffuse transmission member provided between the light source and the inspection object. Wherein the diffuse transmission member is provided with a through hole for inspection, and the transmittance of the diffusion transmission member is gradually increased as the distance from the through hole increases. .

According to a second aspect of the present invention, there is provided an illuminating device comprising a light source and a diffuse reflection member for reflecting the light of the light source and illuminating an object to be inspected at an inspection position. In addition, the gist of the present invention is that a through hole is provided and the reflectance of the diffuse reflection member gradually increases as the distance from the through hole increases.

[0011]

According to the first aspect of the present invention, the light transmittance of the diffusion transmitting member is configured to gradually increase as the distance from the hole increases, so that when the surface of the object to be inspected has gloss. Shows a gradual change curve in which the brightness signal obtained by imaging is darkest at the portion corresponding to the through-hole and gradually becomes brighter as the distance from the through-hole increases. Therefore, the peak value of the differentiated signal obtained by differentiating this does not exceed the predetermined threshold value, and it is possible to reliably determine the defective portion.

On the other hand, when the surface of the inspection object has no gloss, the illumination light reaching the portion corresponding to the through hole on the inspection object surface is the smallest, and the illumination light gradually increases as the distance from the illumination light increases. Since the illumination light is diffused and the illumination light is further diffused on the surface of the inspection object, the level difference between the portion corresponding to the through-hole and the other portion of the brightness signal obtained by imaging does not greatly differ. Therefore, even when the surface of the inspection object has no gloss, it is possible to reliably determine the defective portion.

According to the second aspect of the present invention, since the reflectance of the diffuse reflection member is configured to gradually increase as the distance from the hole increases, the irradiation light that reaches the surface of the inspection object emits the above-described light. As in the case where the diffusion transmitting member is used, the portion corresponding to the through hole is the smallest, and gradually increases as the distance from the hole increases. Therefore, the defective portion can be reliably determined both in the case where the surface of the inspection object has gloss and in the case where the surface of the inspection object does not have gloss, by the same operation as the case where the above-mentioned diffusion transmission member is used.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a sectional view showing an embodiment of the invention according to claim 1 (hereinafter, referred to as a first embodiment). As shown in FIG. 1, the apparatus of the first embodiment includes a transport device (4) for transporting an inspection object (m) and a light source for illuminating the inspection object (m) transported by the transport device (4). A diffuse transmission member (2) provided between (1), the inspection object (m), and the light source (1).
And an image sensor (5) for imaging the inspection object (m).

The transfer device (4) comprises side walls (4a) and (4a) which are arranged side by side at predetermined intervals, and a pair of endless belts (4c) and (4c) provided at the upper end thereof. A pressure reducing means (not shown) for generating a negative pressure between the side walls (4a), (4a); and the pair of endless belts (4c),
And a driving means (not shown) for driving (4c) in the transport direction. The object (m) is sucked and held on endless belts (4c) and (4c) as shown in the figure.
It can be transported in a predetermined direction.

The light source (1) is a high-power and high-intensity lamp such as a halogen lamp provided diagonally above and below the transport device (4) as shown in FIG. 1, and is transported by the transport device (4). The object (m) to be inspected is illuminated.

The diffusing and transmitting member (2) is a member having a shape that covers the inspection object (m) at the inspection position, that is, a spherical shell shape. A film or the like can be applied. Further, a through hole (3) for imaging is provided at the top of the diffusion transmitting member (2), and an image sensor (5) is provided above the through hole (3). The through hole (3) has a slit shape corresponding to the scanning direction of the image sensor (5).

The light transmittance of the diffusion / transmission member (2) is set so as to gradually increase as the distance from the through hole (3) increases. For example, a diffuse transmission auxiliary member (2
Of the a), the one having the lowest light transmittance is adhered around the through hole (3), and the one with the light transmittance gradually increasing as the distance from the through hole (3) increases. Alternatively, a plurality of diffusion / transmission auxiliary members (2a) having the same light transmittance are laminated and adhered closer to the through hole (3), and the number of adhered layers is reduced as the distance from the through hole (3) decreases, and the light is transmitted. Change the rate. Further, there is a method in which the closer to the through-hole (3), the color of the diffuse transmission member (2) is colored with a darker brightness, and the farther from the through-hole (3), the brighter the color.

The shape of the diffusion transmitting member (2) is not limited to the above-mentioned spherical shell shape, but may be a flat plate shape as long as the object (m) can be sufficiently illuminated. The shape of (3) can also be appropriately set according to the type of the imaging camera.

According to the first embodiment, when the surface of the inspection object (m) has gloss, the inner surface of the diffusion transmitting member (2) is projected on the surface of the inspection object (m). FIG.
An actual image shown in FIG. In the figure, (3 ') is a portion corresponding to the through hole (3), and (2a') is a portion corresponding to the diffusion / transmission auxiliary member (2a). The brightness level of the scan line 1 of the actual video is as shown in FIG. That is, the lightness level corresponding to the through hole (3) is the lowest, and the lightness level gradually increases as the distance from the through hole (3) changes with the change in the light transmittance of the diffusion transmitting member (2). Note that (7) is a defective portion, but the brightness level of this portion shows as dark as the brightness level corresponding to the through hole (3).

The differential signal obtained by differentiating the brightness signal has a small peak value in a portion associated with a change in the transmittance of the diffuse transmission member (2) and a large peak value in a defective portion (7). . Therefore, it is possible to reliably detect the defective portion (7) by setting the change in the transmittance of the diffusion transmitting member (2) to a gradual degree that can detect the defective portion, and setting an appropriate threshold value. it can.

On the other hand, although not particularly shown, when the surface of the inspection object (m) has no gloss, the illumination light reaching the portion corresponding to the through hole (3) on the surface of the inspection object (m) is The illumination light is diffused light, and the illumination light is diffusely reflected and diffused on the surface of the inspection object, so that the brightness signal obtained by the imaging passes through the through-hole (3). The level difference between the corresponding part and the other part is not much different. Therefore, the differential peak value of the portion corresponding to the through hole (3) of the differential signal obtained by differentiating the differential signal is much smaller than that of the defective portion, so that the defective portion can be reliably detected.

Next, an embodiment of the invention according to claim 2 will be described. FIG. 3 is a sectional view showing an embodiment of the invention according to claim 2 (hereinafter, referred to as a second embodiment).

As shown in the figure, the apparatus of the second embodiment is different from the apparatus of the first embodiment in that the diffuse transmission member (2) is a diffusion reflection member (6), and the spherical shell-shaped diffusion reflection member is used. The light source (1) is provided so as to illuminate the inner surface of (6), and the inspection object (m) is illuminated by the reflected light from the diffuse reflection member (6).

As the diffuse reflection member (6), papers or plastic sheets / films for irregularly reflecting received light can be used. The reflectivity of the diffuse reflection member (6) is gradually increased as the distance from the through hole (3) increases. Among the diffuse reflection auxiliary members (6a) having different reflectivities, the one having the lowest reflectivity is used. Next, a member having a low reflectance is attached around (3) to change the reflectance of the member. Alternatively, the color closer to the through-hole (3) may be colored darker with lightness, and the farther away from the hole (3), the brighter the color may be colored.

According to the apparatus of the second embodiment, similarly to the apparatus of the first embodiment, when the surface of the object (m) has a gloss, the image is projected on the surface of the object (m). The reflection surface of the diffuse reflection member (6) is imaged by the image sensor (5). Since the reflectance of the reflection surface of the diffuse reflection member (6) is increased as the distance from the hole (3) increases, the brightness signal to be imaged is darkest at the portion corresponding to the hole (3), and gradually increases as the distance increases. It will be bright. Therefore, a brightness signal and a differential signal similar to those in the first embodiment shown in FIGS. 2B and 2C can be obtained, and the defective portion can be reliably detected.

When the surface of the inspection object (m) has no gloss, the reflectance of the diffuse reflection member (6) is gradually increased as the distance from the hole (3) increases, so the inspection object (m) The illumination light reaching the portion corresponding to the through-hole (3) on the surface of the specimen has the smallest amount, and gradually increases as the distance from the illumination light increases. However, as in the first embodiment, the illumination light reaches the surface of the inspection object (m). The light is irregularly reflected, and the level difference between the brightness signal and the other portion corresponding to the through hole (3) is not substantially different. Therefore, also in this case, the defective portion can be reliably detected.

In the first and second embodiments, the light source (1) directly illuminates the diffuse transmitting member (2) or the diffuse reflecting member (6). However, the present invention is not limited to this. Instead, an optical fiber bundle is interposed between the diffuse transmission member (2) or the diffuse reflection member (6) and the light source (1), and the optical fiber bundle on the light projecting side is branched and dispersed to illuminate. It may be. With this configuration, the entire surface of the diffuse transmission member (2) or the diffuse reflection member (6) can be illuminated with substantially uniform illuminance, and a decrease in inspection accuracy due to a partial decrease in illuminance can be prevented. it can.

[0029]

As described in detail above, according to the present invention, it is possible to reliably detect a defective portion existing on the surface of an object to be inspected, regardless of whether or not the surface has gloss. it can.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing video data and a brightness signal obtained by illuminating by the first embodiment device, and a differential signal after differential processing.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a conventional lighting device.

FIG. 5 is an explanatory diagram showing video data and a brightness signal obtained by illumination by a conventional illumination device, and a differential signal after differential processing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Diffusion transmission member 2a Diffusion transmission auxiliary member 3 Through-hole 4 Transport device 5 Image sensor 6 Diffuse reflection member 6a Diffuse reflection auxiliary member 7 Defective part m Inspection object l Scan line

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-167450 (JP, A) JP-A-51-11464 (JP, A) JP-A-54-135547 (JP, A) JP-A-59-114 119246 (JP, A) JP-A-63-53452 (JP, A) JP-A-2-167450 (JP, A) JP-A-4-66849 (JP, A) JP-A-4-309849 (JP, A) Japanese Utility Model No. 4-51610 (JP, U) Japanese Utility Model No. 4-64715 (JP, U) Japanese Utility Model No. 1-117758 (JP, U)

Claims (2)

(57) [Scope of request for utility model registration] 1. A light source (1) for illuminating an inspection object (m) at an inspection position, and a diffusion transmitting member (2) provided between the light source (1) and the inspection object (m). An illumination device, wherein a through hole (3) for inspection is provided in the diffusion / transmission member (2), and the transmittance of the diffusion / transmission member (2) gradually increases as the distance from the through hole (3) increases. A lighting device for inspection characterized by having been configured as described above. 2. An illumination device comprising: a light source (1); and a diffuse reflection member (6) that reflects light from the light source (1) and illuminates an inspection object (m) at an inspection position. The diffuse reflection member (6) is provided with a through hole (3) for inspection, and the reflectance of the diffusion reflection member (6) is gradually increased as the distance from the through hole (3) increases. Lighting equipment for inspection.