JPH07243988A - Surface inspecting device - Google Patents

Abstract

PURPOSE:To provide a surface inspecting device having a relatively simple structure and no illumination irregularity and capable of generating the illumination light with a strong intensity and correctly making the surface inspection of an object to be inspected. CONSTITUTION:Spot beams generated from multiple laser beam sources 1 and having strong directivity are projected on the surface 3a of an object 3 to be inspected in a line shape at the prescribed angle against the surface 3a, and adjacent spot beams are partially overlapped to have no illumination irregularity. The reflected light from the surface 3a of the projected spot beams is received by a light reception section 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface inspection apparatus for inspecting the condition of a surface of an object to be inspected, such as a steel plate, by irradiating the surface with light and receiving reflected light from the surface.

[0002]

2. Description of the Related Art This type of surface inspection apparatus performs line illumination in a width direction orthogonal to the moving direction on a surface of an object to be inspected such as a steel plate which is moving in a manufacturing line,
As the inspection object moves, the surface of the inspection object is inspected.

As a method of producing this line illumination,
Conventionally, the light of a fluorescent lamp is condensed by a cylindrical lens or a concave mirror to be line illumination, or the light of a point light source such as a halogen bulb is condensed and guided by a large number of fine optical fibers. Line up the emission tips,
There are methods such as line lighting.

[0004]

As described above, in the method of producing line illumination by using a fluorescent lamp, the fluorescent lamp itself is an aggregate of luminous fluxes diverging from each point, so that it is collected by a collimator or a lens. There is a problem that the efficiency is low for lighting, and even if an attempt is made to increase the brightness, the power of the fluorescent lamp is limited, the brightness cannot be increased so much, and the line length is limited. .

Further, in the method of producing line illumination using an optical fiber, the light of the light source is attenuated when passing through the fiber, so that the power of the light source cannot be effectively utilized, and especially the fiber length is long. This is a problem and there is a limit to the length of the line.

The present invention has been made in view of the above,
An object of the invention is to provide a surface inspection device which can generate an illumination light having a high brightness with a relatively simple structure and no illumination unevenness and which can appropriately perform a surface inspection of an object to be inspected. Especially.

[0007]

In order to achieve the above object, a surface inspection apparatus of the present invention is a surface inspection apparatus for irradiating a surface of an object to be inspected with light to perform the surface inspection. A light source means for projecting a plurality of highly directional spot lights, which are adjacent to each other so that there is no uneven illumination in a line on the surface of the object, at a predetermined angle with respect to the surface of the object to be inspected. And a light receiving means for receiving the reflected light from the surface of each spot light from the light source means.

Further, the surface inspection apparatus of the present invention projects a plurality of spot lights for performing area illumination having overlapping illumination areas so as to have a predetermined length even in the direction orthogonal to the width direction of the inspection object. The gist is to have a light source means for emitting light and a light receiving means for receiving reflected light of each spot light from the light source means from the inspected object.

[0009]

In the surface inspection apparatus of the present invention, a plurality of spotlights having a strong directivity from the light source means are provided on the surface of the object to be inspected so that adjacent spots of the spotlights partially overlap each other and do not have illumination unevenness in a line shape. It is projected at an angle.

Further, in the surface inspection apparatus of the present invention, the plurality of spot lights overlap each other with a predetermined length even in the direction orthogonal to the line direction of the object to be inspected, thereby performing area illumination without illumination unevenness. ing.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a diagram showing the configuration of a surface inspection apparatus according to an embodiment of the present invention. In the figure, the inspection object 3 such as a steel plate is moving in the direction indicated by the arrow 21, and the directivity from the plurality of laser light sources 1 is strong with respect to the moving surface 3a of the inspection object 3. Spot light is projected through each lens 2, and a plurality of spots 6 are shown on the surface 3a. These spots 6
An arrow 22 which is the width direction orthogonal to the moving direction of the inspection object 3
The surface 3a is illuminated substantially in a line in the line direction indicated by, and adjacent spots 6 partially overlap with each other by a certain amount to form an overlap portion 5.

Further, in this way, the spot 6 is attached to the object 3 to be inspected.
In order to form the plurality of laser light sources 1 side by side in the line direction 22 which is the width direction, the plurality of laser light sources 1 are also arranged side by side in the line direction 22. In this case, the optical axes of the spot lights from the laser light sources 1 are aligned so that the spot lights from the laser light sources 1 coincide with the line illumination center 4.

As described above, the reflected light from the surface 3a of the object 3 to be inspected which is linearly illuminated by the spot light from the laser light source 1 is received by the light receiving section 11 via the condenser lens 10. Has become. Then, the light receiving unit 11 is configured to perform the surface inspection of the inspection object 3 based on the reflected light from the surface 3a of the inspection object 3.

The light intensity of a single spot light from each laser light source 1 draws a Gaussian distribution curve as shown by 8 in FIG. 1 (b), but each spot light is spotted in FIG. 1 (b). By partially overlapping each other as shown in group 7, the light intensity of each spot light is added to the light intensity in this spot group 7 to obtain a spot intensity distribution as shown by 9 in FIG. 1 (b). Therefore, it is possible to perform uniform and even line illumination. By performing uniform and even line illumination on the surface of the inspection object 3 in this manner, the surface inspection of the inspection object 3 can be performed accurately.

It is to be noted that the spot light from each laser light source 1 having the spot intensity distribution of the Gaussian distribution curve as shown by 8 in FIG. 1 (b) gives a uniform spot intensity distribution as shown by 9 in FIG. 1 (b). To obtain each laser light source 1
It is only necessary to adjust the position in the line direction and adjust the size of the overlapping portion 5.

FIG. 2 is a diagram showing another embodiment of the present invention. In addition to arranging the spots 6 from the plurality of laser light sources 1 shown in FIG. 1A in the line direction 22, the embodiment shown in FIG. Are arranged so as to overlap with each other, and by such a structure, it is possible to perform uniform illumination in an area shape so as to show the spot intensity at 12. The plurality of laser light sources 1 in this case are configured by arranging two or more rows of the laser light sources 1 arranged in a line as shown in FIG. 1A, but the present invention is not limited to this. For example, even if the arrangement of the plurality of laser light sources 1 is not particularly specified, only the irradiation direction of the spot light is adjusted to form an area on the surface of the inspection object 3 as shown in FIG. It is good if it becomes.

FIG. 3 is a diagram showing still another embodiment of the present invention. In the embodiment shown in FIG. 3, the direction of the spot light from the plurality of laser light sources 1 in the embodiment shown in FIG. 1 is inclined with respect to the surface 3a of the inspection object 3 with a projection angle θ, whereby the spot light is The specular reflection component of the light reflected by the surface 3a is guided to the light receiving unit 11. In this way, the specular reflection component of the spot light is guided to the light receiving unit 11, so that the light receiving unit 11 can more accurately perform the surface inspection of the inspection object 3.

[0018]

As described above, according to the present invention,
A plurality of highly directional spot lights from the light source means are projected onto the surface of the object to be inspected at a predetermined angle so that adjacent spots of the adjacent light beams partially overlap each other. Therefore, it is possible to generate the illumination light with high brightness and to accurately perform the surface inspection of the inspection object.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration and a brightness distribution of a surface inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing another embodiment of the present invention.

FIG. 3 is a diagram showing still another embodiment of the present invention.

[Explanation of symbols]

 1 Laser Light Source 2 Lens 3 Inspected Object 3a Surface of Inspected Object 5 Overlap 6 Spot

Claims (4)

[Claims] 1. A surface inspection apparatus for irradiating a surface of an object to be inspected with light to inspect the surface of the object to be inspected. A surface comprising light source means for projecting light at a predetermined angle with respect to the surface of the object to be inspected, and light receiving means for receiving reflected light of each spot light from the light source means from the surface. Inspection device. 2. A surface inspection apparatus for irradiating a surface of an object to be inspected with light to inspect the surface of the object to be inspected, the illumination areas overlapping each other so as to have a predetermined length even in a direction orthogonal to a width direction of the object to be inspected. And a light receiving means for receiving a plurality of spot lights for illuminating the area, and a light receiving means for receiving reflected light of each spot light from the light source means from the object to be inspected. Inspection device. 3. The surface inspection apparatus according to claim 1, wherein the light source means is composed of a plurality of light sources that respectively generate spot lights having strong directivity. 4. The surface inspection apparatus according to claim 1, wherein the light source means is a laser light source.