JPH06229944A - Optical apparatus and method for inspecting surface - Google Patents

Abstract

PURPOSE:To enable sure and quick detection of a minute variation in the state of a surface by preparing a bright-and-dark pattern by generating bright and dark parts alternately by an illuminating device. CONSTITUTION:A light diffused by a light diffusing plate 4 is separated into the part of a transmitted light and that of an intercepted light by a light control member 5 and the light reaching a light-transmitting part 51 is transmitted therethrough and irradiates a substance 6 to be inspected, while the light reaching a light-intercepting part 52 is prevented from being transmitted. On the surface of the substance 6, therefore, a bright part irradiated directly by the light and a dark part to be made a half-shade part by an indirect light are formed alternately and a bright-and-dark fringe pattern is formed. When the substance 6 is moved by a conveying device 7, the part of a flaw moves from the bright part to the dark part and further to the bright part, a reflection characteristic varies and the part can be discriminated as the flaw. In this way, a minute flaw, an indentation, a foreign matter sticking on the surface or the like can be distinguished surely and quickly without necessitating any skill, and thus the efficiency and precision of inspection are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical surface inspection device and a surface inspection method for inspecting the surface condition of various objects.

[0002]

2. Description of the Related Art For example, painted or plated surfaces of various objects,
Alternatively, when checking the finish of the polished surface, etc., the surface of the object to be inspected is touched directly by hand, and the presence or absence of scratches is checked by the touch, that is, the touch. If the area of the object to be inspected is large and the inspection accuracy is poor, the inspection becomes impossible.
Further, as another surface inspection method, light is applied to the surface of the object to be inspected, and the shape of these surfaces, the flatness, the presence or absence of scratches are examined by observing the reflection of this light. That is, light is uniformly reflected on a cleanly finished surface, and if there are scratches or undesired irregularities, the light reflection characteristics change. Therefore, the surface state can be known by examining this.

[0003]

However, when the surface is inspected by the above-mentioned light reflection condition, if the brightness of the surface of the object to be inspected is uniform and does not change, fine scratches can be identified. However, such a flaw is easy to overlook, and thus requires a lot of skill in the inspection and needs to be reviewed many times.

The present invention has been made under such circumstances, and an object thereof is to provide an optical surface inspection apparatus and a surface inspection method capable of surely and quickly inspecting minute changes in the surface condition. Is what you are trying to do.

[0005]

The present invention comprises:

In an apparatus for irradiating the surface of an object to be inspected with light and inspecting the surface condition by the degree of reflection of this surface, the illuminating device for irradiating the surface of the object to be inspected with light is a portion that illuminates the surface brightly. The light and dark portions are alternately generated to produce a bright and dark pattern. Further, the present invention, on the surface of the object to be inspected, a illuminating device that creates a bright and dark pattern by alternately generating a portion that is illuminated by shining light and a portion that is darker than the bright portion,

A means for moving at least one of the illumination device and the object to be inspected in order to move the light and dark pattern generated on the surface of the object to be inspected along the surface of the object to be inspected. And Further, the optical surface inspection method of the present invention,

[0008] On the surface of the object to be inspected, a portion which is brightened by direct application of light and a portion which is darkened by blocking light to create a shadow are alternately generated. It is characterized in that the relative condition of the surface of the object to be inspected is changed by relatively moving it on the surface of the object to be inspected, and the surface state is examined by the change in the reflection.

[0009]

According to the present invention, bright portions on the surface of the object to be inspected, which are illuminated by the light emitted from the lamp, and dark portions, which are darker than that, are alternately formed. As the light is irradiated, the degree of surface reflection of this bright portion becomes clear and the surface state can be easily discriminated.

Further, according to the present invention, if at least one of the position of the illumination device and the object to be inspected is changed, the reflection condition is changed. Or, on the contrary, the shadowed part changes such as reflecting light, so you can easily find minute scratches etc., and you can identify them reliably and quickly, and the surface of the object to be inspected You can check the condition effectively.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In the drawings, reference numeral 10 indicates a lighting device,
Among them, reference numeral 1 is a lamp housing, which has a box shape with an inner surface having a reflecting surface 2 of white or the like and an open lower end. In the lamp housing 1, a light source, for example, a plurality of straight tube fluorescent lamps 3 ... Are housed side by side in the horizontal direction. The light emitted from these lamps 3 ...
One part is reflected by the reflecting surface 2 of the lamp housing 1, and the rest is directly irradiated downward, so that the lamp housing 1
It is designed to radiate downward from the open end of the bottom.

A light diffusing plate 4 is provided at the lower end open portion of the lamp housing 1. The light diffusing plate 4 diffuses the light emitted downward from the lower end open portion of the lamp housing 1, whereby the light transmitted through the light diffusing plate 4 is diffused, and the brightness on the lower surface of the light diffusing plate 4 is reduced. It is controlled so as to be substantially equal over the entire surface.

A light control member 5 is provided below the light diffusion plate 4. The light-blocking member 5 is made of, for example, a light-blocking plate material, and has slits serving as a large number of light-transmitting portions 51 ... Formed at equal intervals. That is, this light control member 5
Are formed by alternately forming slit portions which become the light transmitting portions 51 ... And light shielding portions 52 which block light, at equal intervals.

An object 6 to be inspected is arranged below the light control member 5. The object 6 to be inspected is placed on the conveying member 7, whereby the surface to be inspected of the object 6 to be inspected faces the light control member 5, and the conveying member 7 moves at a constant speed or intermittently in the arrow direction, for example. It is supposed to be moved together by moving to.

In such a structure, the light diffused by the light diffusing plate 4 is divided by the light control member 5 into a transmitted light portion and a light shielding portion. That is, the light reaching the light transmitting portion 51 formed in the light control member 5 is transmitted through the light transmitting portion 51 to illuminate the inspection object 6, and the light reaching the light shielding portion 52 is transmitted through the light shielding portion 52. Is hindered.

Therefore, on the surface of the object 6 to be inspected, a bright portion 61 directly irradiated with light and a dark portion 62 which becomes a penumbra due to indirect light which is not reached by direct light are alternately formed. That is, a striped pattern due to light and darkness of light is formed.

Here, when the surface of the object 6 to be inspected is beautifully finished, in the bright portion 61 to which the light is directly irradiated, when viewed from a predetermined direction, it is uniformly brightly reflected and dark. Even if it is dark in the portion 62, when viewed from a predetermined direction, it looks uniformly dark throughout.

However, when there is a scratch on the surface of the object 6 to be inspected, for example, when the scratch is present in the bright portion 61 directly irradiated with the light (A in FIG. 3), this may be caused depending on the condition of the scratch. The surface of the scratch does not reflect light in a predetermined direction but reflects it in an undesired direction. Therefore, depending on the angle at which the scratch is viewed, the shadow may appear darker than other bright areas. On the other hand, when the scratch is present in the dark portion 62 where the light is blocked (B in FIG. 3), indirect light may be reflected in a predetermined direction on the surface of the scratch depending on the condition of the scratch. . Therefore, depending on the angle at which this flaw is viewed, it may appear brighter than other dark areas. That is, even with the same scratch, there is a difference between the reflection characteristic when it exists in the bright portion 61 (A in FIG. 3) and the reflection characteristic when it exists in the dark portion 62 (B in FIG. 3).

Therefore, the object to be inspected 6 is conveyed by the carrier device 7.
Move in the direction of the arrow,
From the dark part 62 to the brighter part 61,
During this time, the reflection characteristic changes, and for example, the flaw looks like a shadow or looks like a bright spot, which can be identified as a flaw.

Therefore, according to such an inspection method and apparatus, it is possible to surely and quickly identify fine scratches and irregularities or foreign substances adhering to the surface without requiring skill, and the inspection efficiency and accuracy are improved. improves.

When inspecting the surface of the inspection object 6,
Although it is possible for an operator to directly inspect it, a monitor camera takes a picture of the reflection condition of the surface of the object 6 to be inspected as described above, and this is reflected on a monitor TV for remote inspection, or It can also be applied to means for automatically identifying defective products by image processing and automatically selecting them. The bright and dark pattern generated on the surface of the inspection object 6 is not limited to the striped pattern, and may be, for example, a lattice pattern, a concentric ring pattern, or the like.

Further, the light source is not limited to the straight tube fluorescent lamp, various lamps can be used, and the light diffusing plate 4 can be replaced with a means for transmitting light into parallel rays. is there. Furthermore, instead of moving the inspection object 6 in the direction of the arrow, the entire illumination device 10 or the light control member 5 may be moved.

Further, in the above description, the object 6 to be inspected, the illuminating device 10, or the light control member 5 is moved relatively, but the present invention is not limited to this, and the surface of the object 6 to be inspected is bright or dark. It is also possible to use only the lighting device 10 that generates the pattern. That is, since the lighting device 10 produces a bright and dark pattern, the bright portion is irradiated with light that does not diffuse, and the reflection of the surface becomes clear at the bright portion, so that the surface state can be easily discriminated. be able to. Therefore, relative movement of the inspection object 6 and the illumination device 10 is not restricted.

[0025]

As described above, according to the present invention, the light which is not diffused is irradiated in the bright portion, the reflection condition of the surface of the bright portion becomes clear, and the surface condition can be easily discriminated. be able to.

When the object to be inspected and the illuminating device are moved relative to each other, the degree of reflection on the surface of the object to be inspected changes. Part of the shadow changes, or conversely, the part that is in shadow changes such as reflecting light, so that it is possible to reliably and quickly perform fine scratches or irregularities without admitting skill, or foreign matter attached to the surface. It is possible to distinguish the above, and the inspection efficiency and accuracy are improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an optical surface inspection apparatus showing an embodiment of the present invention.

FIG. 2 is a view for explaining the operation of the embodiment.

FIG. 3 is a view for explaining the principle of the same embodiment.

[Explanation of symbols]

1 ... Lamp Hauzong 3 ... Straight tube type fluorescent lamp 4 ... Light diffusing plate 5 ... Light control member 6 ... Inspected object 7 ... Conveying device 10 ... Illumination device 51 ... Light transmitting part 52 of light control member ... Light control member Light-shielding portion 61 ... Brightly illuminated portion of the inspection object 62 ... Dark portion of the inspection object

Claims (5)

[Claims] 1. An apparatus for irradiating light on the surface of an object to be inspected and inspecting the surface condition according to the reflection of the surface, wherein an illuminating device for irradiating light to the surface of the object to be inspected illuminates the surface brightly. An optical surface inspection device characterized in that bright and dark patterns are produced by alternately generating portions and portions darkened from the bright portions. 2. An illumination device for illuminating a surface of an object to be inspected with light so as to alternately generate a portion that is illuminated brightly and a portion that is darker than the bright portion, and a surface of the object to be inspected. An optical surface inspection apparatus comprising: a means for moving at least one of the illumination device and the object to be inspected so as to move the bright and dark pattern generated on the object along the surface of the object to be inspected. 3. The illumination device is provided between a lamp for irradiating the surface of an object to be inspected with light, and between the lamp and the object to be inspected, and transmits the light emitted from the lamp to inspect the object to be inspected. And a light-shielding member alternately provided with a light-transmitting portion that generates a bright portion on the surface of the object and a light-shielding portion that shields the light emitted from the lamp to generate a dark portion on the surface of the object to be inspected. The optical surface inspection apparatus according to claim 1 or 2, wherein: 4. The optical surface inspection device according to claim 3, further comprising a diffusion plate provided between the lamp and the light control member for diffusing light emitted from the lamp. 5. The surface of the object to be inspected is alternately generated with a portion which becomes bright by directly shining light and a portion which becomes dark by blocking light to form a shadow, and a portion of a pattern due to light and dark of this light. Is relatively moved on the surface of the object to be inspected, thereby changing the reflection condition of the surface of the object to be inspected, and the surface state is examined by the change in the reflection. Inspection method.