JP4262413B2 - Lighting device for inspection - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wrinkle inspection illumination device, and more particularly to a wrinkle inspection illumination device that optically inspects wrinkles by illuminating the surface of a strip-shaped or plate-shaped inspection object.
[0002]
[Prior art]
As one of the band-shaped or plate-shaped wrinkle inspection apparatuses, there is an optical wrinkle inspection apparatus. The optical wrinkle inspection device includes an illumination device that forms a linear illumination pattern on the surface of a material to be inspected. For example, a linear illumination pattern is formed on the surface of the steel sheet while feeding the steel sheet in the longitudinal direction, and the inspection operator directly looks at the surface of the steel sheet or inspects the wrinkles on the monitor screen.
[0003]
Conventionally, a rod-shaped light source of an illuminating device typified by a fluorescent lamp has been extremely insufficient in light quantity and light collecting property. In addition, the distance to the material to be inspected cannot be taken, the temperature change is weak, there is no directivity, and it is difficult to construct a long (for example, 2 m) rod-shaped light source. The imaging resolution could not be increased. Optical fiber illumination is expected as an illumination device that solves such problems, and various optical fiber illumination devices have been developed.
[0004]
The optical fiber illuminating device includes a light source, a sheet-shaped optical fiber bundle in which a large number of optical fibers are aligned, and a condensing lens that forms a linear irradiation pattern on the surface of a strip-shaped or plate-shaped inspection material. . The conventional optical fiber lighting device is a combination of a commercially available optical fiber bundle and a condensing lens (cylindrical lens), but has the following problems.
[0005]
In order to require an optical fiber bundle that is aligned long in the width direction (perpendicular to the optical axis of the optical fiber) according to the width of the material to be inspected, several optical fiber bundles 24 having a width of about 500 mm are joined in the width direction. It was. In the optical fiber bundle, the optical fibers are stacked in a plurality of stages. However, as shown in FIGS. The center of the dent is recessed or swollen. Due to these dents and bulges, the illumination light rays are uneven. When the distance between the condensing lens 40 and the material to be inspected is about several meters, the materials to be inspected are uneven on the order of several mm as shown in FIG. As a result, the illuminance on the surface of the material to be inspected became non-uniform and the wrinkle detection ability was reduced.
[0006]
As an illumination device using a rod-shaped light source, for example, there is a surface inspection device disclosed in Japanese Patent Application Laid-Open No. 2000-65555. As an illuminating device including an optical fiber bundle and a condensing lens, for example, there is an illuminating device disclosed in Japanese Unexamined Patent Publication No. 2000-149607.
[0007]
[Problems to be solved by the invention]
The subject of this invention is providing the illuminating device for a wrinkle inspection which can irradiate the surface of a to-be-inspected material, and can detect wrinkles with high wrinkle detection ability, without the rays of illumination light becoming uneven.
[0008]
[Means for Solving the Problems]
The illuminating device for wrinkle inspection of the present invention is a illuminating device for wrinkle inspection in which a linear irradiation pattern is formed on the surface of a strip-shaped or plate-shaped material to be inspected. A plurality of optical fiber bundles aligned in a direction, an optical fiber unit joined so that the optical fiber bundles are aligned along the alignment direction, and a plurality of condensing lenses including cylindrical lenses in the alignment direction of the optical fibers. And a light collecting unit joined so as to line up.
[0009]
Moreover, in this invention, you may make it bend the said condensing unit according to the bending of the said optical fiber unit. By adjusting the deflection of the condenser lens, irregular light rays from the optical fiber bundle can be aligned in parallel.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
1, 2 and 3 schematically show the illumination device of the present invention. The illuminating device mainly includes a light source, a light guide part, and a light collecting part.
[0011]
The light source 10 includes a high brightness point light source 12 and a concave mirror 14. As the high brightness point light source 12, for example, a metal halide lamp, a halogen lamp, a xenon lamp or the like is used. An elliptical mirror or a parabolic mirror is suitable as the concave mirror 14.
[0012]
The light guide unit 20 includes an optical fiber cable 29 extending from the light source 10 to the optical fiber unit 21. In the optical fiber cable 29, a large number of optical fibers 26 are bundled and covered with a plastic sheath. Inside the optical fiber unit 21, the optical fiber 26 is branched and aligned from the tip of the optical fiber cable 29 to form an optical fiber bundle 22 (shown in FIG. 3). The optical fiber bundle 22 is configured by aligning a number of optical fibers 26 in a direction perpendicular to the optical axis (lateral direction) and stacking a plurality of stages. The optical fiber bundles 22 adjacent to each other in the lateral direction are band-shaped with side ends joined together with an adhesive in accordance with the width of the material to be inspected 1 and extending in the lateral direction. The optical fiber unit 21 is held between the upper plate 31 and the lower plate 32 and held by the optical fiber holding frame 30.
[0013]
The light collecting unit 40 includes a light collecting unit 41 including a plurality of light collecting lenses 42. A cylindrical lens is used as the condenser lens 42. The condensing lenses 42 adjacent in the horizontal direction are elongated in the horizontal direction by connecting side ends with an adhesive in the same manner as the optical fiber bundle 22. The joint 43 of the condenser lens 42 is positioned so as to be displaced laterally with respect to the joint 23 of the optical fiber bundle 22. This shift is such that the lens joint is located in the middle of each optical fiber. Accordingly, there is no reduction in illuminance due to the overlap between the joint 23 of the optical fiber bundle 22 and the joint 43 of the condenser lens 42.
[0014]
In the apparatus configured as described above, the illumination light from the high-intensity point light source 12 is condensed at the incident end of the optical fiber cable 29 by the concave mirror 14. The illumination light is guided to the optical fiber unit 21 via the optical fiber cable 29. The illumination light emitted through the optical fiber unit 21 is condensed by the condenser lens 42 to form a linear illumination pattern 5 on the surface 1 to be inspected. The inspection object 1 moves in the longitudinal direction S thereof, and the eyelid F is imaged by the linear array camera 60.疵 F is detected by visual observation on a monitor (not shown) or by image processing of a video signal. There is no reduction in illuminance due to the overlap between the joint 23 of the optical fiber bundle 22 and the joint 43 of the condenser lens 42. For this reason, it is possible to uniformly irradiate the surface of the material to be inspected and detect wrinkles with high wrinkle detection ability.
FIG. 4 shows an embodiment of the illumination device of the present invention. As shown in FIG. 4A, the light collecting unit 49 is held by the lens holding frame 50. An adjusting screw 52 is fitted to a nut 51 attached to the lens holding frame 50. The tip of the adjustment screw 52 is pressed against the condensing lens 49, and the adjustment screw 52 adjusts the bending of the condensing lens 49 to the bending of the optical fiber bundle. By adjusting the deflection of the condenser lens, irregular light rays from the optical fiber bundle can be aligned in parallel. FIG. 4B shows an illumination pattern on the surface of the material to be inspected, and the curved ray locus 8 can be corrected to the reference straight line 7 by adjusting the deflection of the condenser lens 49.
[0016]
【The invention's effect】
In the lighting device for eyelid inspection according to the present invention, the condensing unit is held by the lens holding frame, and the bending of the condensing lens can be matched with the bending of the optical fiber bundle by the adjusting screw. By adjusting the deflection of the condensing lens in this way, irregular light rays from the optical fiber bundle can be aligned in parallel, and the curved light ray trajectory can be corrected to a reference straight line. As a result, the surface of the material to be inspected is irradiated without unevenness of the illumination light beam, and soot can be detected with high soot detection ability.
[Brief description of the drawings]
FIG. 1 is a perspective view schematically showing a wrinkle inspection illumination device according to an embodiment of the present invention.
2 is a side view schematically showing an optical system of the illumination device shown in FIG. 1. FIG.
3A is a front view of the apparatus shown in FIG. 1, and FIG. 3B is a plan view.
FIGS. 4A and 4B show an embodiment of a lighting device of the present invention, where FIG. 4A is a front view, and FIG. 4B is a schematic diagram of an illumination pattern.
FIG. 5 is a plan view schematically showing optical fiber irregularities at the side ends of the optical fiber bundle.
FIG. 6 is a front view schematically showing an example of a conventional wrinkle inspection illumination device.
7 is an enlarged view of the optical fiber bundle shown in FIG. 6. FIG.
FIG. 8 is a diagram for explaining unevenness of illumination light rays;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Test material 5 Illumination pattern 7 Reference line 8 Ray trace 10 Light source 12 High-intensity point light source 14 Concave mirror 20 Light guide part 21 Optical fiber unit 22 Optical fiber bundle 23 Joint part 26 Optical fiber 30 Optical fiber holding frame 31 Upper plate 32 Below Plate 40 Condensing part 41 Condensing unit 42 Condensing lens 43 Joint part 49 Condensing lens 50 Condensing lens holding frame 51 Nut 52 Adjustment screw 56 Upper plate F 疵

Claims (1)

In the illumination device for wrinkle inspection that forms a linear irradiation pattern on the surface of a strip-shaped or plate-shaped inspection material,
A plurality of optical fibers are composed of a plurality of optical fiber bundles aligned in the direction perpendicular to the optical axis of the optical fiber and in the width direction of the material to be inspected, and the optical fiber bundles are joined so as to be aligned along the alignment direction. An optical fiber unit;
A plurality of condensing lenses composed of cylindrical lenses, and a condensing unit joined so as to be aligned along the alignment direction of the optical fiber,
The condensing unit is disposed on the exit side of the optical fiber unit;
Of the optical fiber unit, in accordance with the deflection of the direction perpendicular to the alignment direction of the vertically and the optical fiber unit to the optical axis, the light collecting unit, as to parallel alignment of the light beam from the optical fiber bundle A wrinkle inspection illumination device characterized by being bent.

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