JPS6055251A - Lighting device for inspection - Google Patents

Abstract

PURPOSE:To detect many kinds of defects having different optical characteristics including scratches formed in the roll line direction by reducing the luminance of light sources arranged in the roll line direction of a surface to be tested less than that of side light sources at a defective part. CONSTITUTION:Plural spot-like light sources 7 are arranged in the same direction as the roll lines 5 of the surface 4 to be inspected and light sources 8 are arranged on the side of the surface 4 to be inspected. The optical outputs of respective light sources are set up so that the luminance of the light sources 7 is lower than that of the illumination light of the light sources 8 at a defective part 6. Consequently, a stripe-like pattern due to the light sources 7 is formed on the surface 4 to be inspected in the rectangular direction to the roll lines 5, so that a defect other than the defective part 6 can be detected in the same direction as the roll lines 5. Since the illumination light of the light source 8 is diffused and reflected at the defective part 6, said defect can be also detected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an inspection illumination device for detecting defects on the surface of an aluminum plate having roll marks (marks caused by rolling rolls).

Conventional configuration and its problems Inspection lighting equipment for detecting defects in the appearance of products is required in inspection processes in many industries. An inspection lighting device is used that is designed to increase the brightness contrast and color contrast between the defective part and its surroundings, depending on the characteristics and shape of the defect.

A conventional inspection illumination device for detecting defects on a surface to be inspected having specular reflection characteristics, such as an aluminum plate, will be described below.

In order to detect multiple defects with different optical characteristics and shapes occurring on the same inspection target surface, it is necessary to use multiple inspection illumination devices corresponding to each defect. In this case, it is necessary to switch the illumination for each type of defect and perform the inspection, which lowers the efficiency of the inspection work compared to a method that detects all defects at the same time. As an effective illumination method for solving this drawback, a method is known in which a light source having a grid pattern of light-emitting parts and non-light-emitting parts is projected onto a surface to be inspected.

FIG. 1 is a diagram showing a conventional inspection illumination device, in which 1 is an inspection object having specular reflection characteristics, 2 is a light source having a grid pattern consisting of a light emitting part 2a and a non-light emitting part 2b, and 3 is an observation position. be.

By using the inspection illumination device configured as described above, it is possible to eliminate defects that occur in the inspection object 1 having specular reflection characteristics, where the specular reflection component is more than the diffuse reflection component, defects where the diffuse reflection component is more than the specular reflection component, and unevenness. It is possible to simultaneously detect defects with different optical characteristics, such as defects with the same diffuse reflection characteristics as the inspection object 1, such as distortion.

However, when there are roll marks on the surface like an aluminum plate, it has diffuse reflection characteristics in the direction perpendicular to the roll marks, and specular reflection characteristics in the same direction as the roll marks, so the pattern of the light source used The shape is limited to a striped pattern, and the mounting position must be such that the striped pattern is perpendicular to the roll. For this reason, it becomes difficult to detect scratches in the same direction as the roll marks (scratches in the direction perpendicular to the striped pattern). This has the disadvantage that the lighting must be switched depending on the type of inspection.

OBJECT OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks.It is an object of the present invention to solve the above-mentioned conventional drawbacks. It is an object of the present invention to provide an inspection illumination device that can detect defects in an object without switching the illumination.

Structure of the Invention The present invention includes a plurality of point-shaped first light sources arranged in the same direction as the roll eyes of the inspection target surface in the range reflected on the inspection target surface;
and a second light source installed on the side of the surface to be inspected, and the light of each light source is adjusted so that the brightness of the first light source is lower than the brightness at the defective part caused by the illumination light of the second light source. By turning on these two types of light sources at the same time, an inspection illumination device configured to set the output power can be used to examine many types of defects with different optical characteristics, including scratches in the same direction as roll marks. It can be detected without replacing the device.

DESCRIPTION OF THE EMBODIMENTS FIG. 2 shows an inspection illumination device in an embodiment of the present invention. In Figure 2, 4 is an aluminum plate, 5
is a roll eye, 6 is a scratch in the same direction as the roll eye, 7 is a point-like first light source, and 8 is a high-intensity second light source with a narrow light distribution like a spotlight. A plurality of light sources 7 are arranged in the same direction as the roll marks in the reflected range of the surface of the aluminum plate 4, and furthermore, a light source 8 is arranged on the side of the aluminum plate 4. The brightness of the light source 7 is still set to be lower than the brightness at the scratch 60 portion caused by the illumination light from the light source 8.

The operation of the inspection illumination device of this embodiment configured as described above will be described below.

Since the aluminum plate 4 has roll stitches 6, it exhibits diffuse reflection characteristics in a direction perpendicular to the roll stitches 5, and exhibits specular reflection characteristics in the same direction as the roll stitches 6.

Therefore, if a plurality of light sources 7 are arranged in the same direction as the roll stitches 6, a striped pattern by the light sources 7 is formed on the surface of the aluminum plate 4 in a direction perpendicular to the roll stitches. This allows the light source 7 to detect defects other than the scratches 6 in the same direction as the roll eyes 6, as described above. In addition, the light source 8 is used to detect only the scratches 6 in the same direction as the roll eyes 6, and the light source 8 is connected to the aluminum plate 4 as shown in FIG.
By installing it on the side of the scratch 60, the illumination light from the light source 8 is diffusely reflected at the scratch 60, so that the scratch 6 can be detected.

In this embodiment, when light sources 7 and 8 are turned on at the same time, light source 8
Since the brightness of the scratch 6 caused by the illumination light is set to be higher than the brightness of the light source 7, the scratch 6 can be detected at any position on the surface of the aluminum plate 4.

Furthermore, since the light source 8 is installed on the side of the aluminum plate 4, there is almost no diffuse reflection of the illumination light from the light source 8 on the surface of the aluminum plate 4. Therefore, the brightness contrast between the defective part with different optical characteristics other than the scratch 6 obtained by the light source 7 and its surroundings is not reduced by the illumination light from the light source 8.

As described above, according to this embodiment, by setting the light output of each light source so that the brightness of the light source 7 is lower than the brightness at the scratch 60 portion caused by the illumination light of the light source 8,
By lighting these light sources simultaneously without switching them individually,
Many types of defects with different optical properties can be detected, including scratches 6 in the same direction as the roll marks 5.

In this embodiment, a plurality of light sources 7 are arranged in the same direction as the roll eyes 6, but they may be arranged in a grid pattern. This method is particularly effective when the diffuse reflection characteristics of the aluminum plate 4 in the direction perpendicular to the roll stitches 5 are weak or when the aluminum plate 4 is large.

Further, although the light source 8 is a high-intensity light source with a narrow light distribution such as a spotlight, a condensing fluorescent light fixture combined with a reflector may also be used.

Furthermore, if colored light is used as the light source 8, the detection effect of the scratch e will be further improved.

Effects of the Invention As described above, the inspection illumination device of the present invention includes a plurality of point light sources arranged in the same direction as the roll marks of the inspection target surface within the range of illuminating the inspection target surface, and By setting the light output of each light source so that the brightness of the former light source is lower than the brightness of the defective area caused by the illumination light of the latter light source, these light sources can be simultaneously switched without switching them individually. When illuminated, many types of defects with different optical properties can be detected, including scratches in the same direction as the roll eye. Moreover, the effect is further enhanced by using colored light as a light source installed on the side of the surface to be inspected. Furthermore, the configuration of the illumination device for detecting defects other than scratches is simple, and there are fewer restrictions in terms of implementation and cost.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional inspection illumination device, and FIG. 2 is a perspective view of an inspection illumination device according to an embodiment of the present invention. 4... Aluminum plate, 6... Roll number, 6
...Scratches in the same direction as the roll marks, 7..Light source for detecting defects other than scratches, 8..Light source for detecting scratches.

Claims (3)

[Claims] (1) A plurality of point-shaped first light sources arranged in the same direction as the roll marks of the inspection target surface in the range reflected on the inspection target surface, and a second light source installed on the side of the inspection target surface. . An inspection lighting device configured to set the light output of each light source so that the brightness of the first light source is lower than the brightness at the defective part caused by the illumination light of the second light source described later. (2) The inspection illumination device according to claim 1, wherein point light sources are arranged in a lattice pattern in a range where they are reflected on the surface to be inspected. (3) The inspection illumination device according to claim 1, wherein the light source installed on the side of the surface to be inspected emits colored light.