JPH0462332B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a non-contact optical surface defect inspection method.

[Conventional technology]

The product (hereinafter referred to as
Defects are detected by irradiating light from a specific direction onto the surface of the object to be inspected (referred to as the object to be inspected), receiving the diffusely reflected light using an imaging device such as a television camera, and electrically detecting the amount of reflected light. A non-contact optical surface defect inspection method for detecting defects is known. In this type of surface defect inspection method, it is desired to separate and identify the inspection object part from the background part, and conventionally, for example, as shown in FIG. 7, the inspection object is a continuous sheet 11. In this case, the roller 12 is made of a material having a different reflectance from that of the sheet 11.
As shown in the graph of Figure 8, both 1
Due to the difference in the amount of reflected light from the rollers 1 and 12, the part to be inspected (sheet 11) is compared to the background part (roller 1) which is not to be inspected.
It is separated and identified from 2). Further, if the sheet 11 is a product colored in a certain color, separation and identification can be similarly performed by using a roller 12 of a different color from the sheet 11. In FIG. 7, since the sheet 11 meanderes in the X direction on the roller 12, it is necessary to reliably follow the movement to detect defects and maintain inspection accuracy, so the separation of the parts to be inspected as described above is necessary. Identification is extremely important.

[Problem that the invention seeks to solve]

In the case of a simple-shaped object to be inspected where the entire surface is the part to be inspected, as in the example in Fig. 7 above, in other words, when viewed from the direction of inspection, the object to be inspected is When the outline and the inspection target part match, the contrast is increased by giving the background part a different reflectance and hue from the inspection target part, and the inspection target part is separated and identified from the background part. I can do it.

However, when the shape of the object to be inspected is complex, there is no way to easily and reliably separate the part to be inspected from the background as described above, and it is necessary to devise ways to separate the part to be inspected from the background. The current situation is that. For example, as shown in FIGS. 9 and 10, when the inspection target portion 14 is formed on a part of the surface of the inspection object 13, the background portion 15 is also a part of the inspection object 13. Therefore, the reflectance etc. are fixed and both parts 14 and 1
It is difficult to give any contrast to 5. Furthermore, even if an appropriate contrast is obtained by some method, the background portion 15
When the mark 16 etc. is engraved and displayed on the background part 15, the brightness of the background part 15 varies.
As shown in the graph of FIG. 1, there is a problem in that it is difficult to reliably separate and identify the parts to be inspected.

In view of the above-mentioned problems, the present invention provides that, when the part to be inspected is formed in a part of the object to be inspected, the part to be inspected and other parts are generally Focusing on the fact that there is a step between the
The purpose of this invention is to provide a method for reliably and easily identifying a portion to be inspected.

[Means for solving problems]

To achieve the above object, the present invention provides a non-contact optical surface defect inspection method in which an object to be inspected is rotated, and a member having a different reflectance from that of the object to be inspected is elastically arranged. It is characterized in that the inspection object part is identified by rotating or slidingly contacting the outer end of the inspection object part of the object to be inspected and detecting the difference in the amount of reflected light at the contact part.

[Effect]

According to the above-mentioned method of the present invention, the outer edge of the inspection object is detected based on the difference in the amount of reflected light at the contact portion with members having different reflectances, and the outer edge of the inspection object is detected by one rotation of the inspection object. Even if the rotating inspection object deviates from its center due to eccentricity, the inspection area mask of the inspection machine can follow the detected movement of the outer edge of the inspection object. Since it can be moved, stable defect detection performance can be obtained.

〔Example〕

Hereinafter, preferred embodiments of the surface defect inspection method according to the present invention will be described based on the drawings.

First of all, FIGS. 1 to 3 show a method according to the first embodiment, in which reference numeral 1 is a disk-shaped object to be inspected, which is placed and fixed on a rotating disk (not shown) and has a convex step 2. The target portion 3 is formed on the upper surface of the convex step portion 2 . 4 is a material having a different reflectance from the part to be inspected 3 (for example, if the part to be inspected 3 is black or other low reflectance material, it is made of a white material with high reflectance such as Teflon, or if the part to be inspected is white or other material) A disc-shaped reflective member made of a black material with low reflectivity such as carbon (if the material is highly reflective), and is elastically biased by the coil spring 5 to support the supporting member 6. It is rotatably attached to the shaft, and its outer periphery is in rotational contact with the outer peripheral edge 7 (rising surface of the convex end 2) of the portion to be inspected 3 with a constant pressing force. Also,
An imaging device (not shown) such as a television camera or a line camera measures the amount of reflected light from the area A shown in the shaded area in FIG. configured to inspect. The graph in FIG. 4 shows the amount of light reflected from the area A when the inspection target part 3 has a low reflectance and the reflective member 4 has a high reflectance.
There is a significant difference in the amount of reflected light between the two. When the inspected object 1 rotates, the reflecting member 4 also rotates, but the level of reflected light is almost constant. Therefore, even if center runout occurs due to eccentricity of the inspected object 1, the area A can be clearly separated from the By moving the inspection area mask that establishes this, inspection accuracy can be maintained and stable defect detection performance can be obtained.

Next, FIGS. 5 and 6 show a second embodiment of the method of the present invention. Slide it into contact with the outer peripheral edge 7 of the inspection target part 3 of the rotating inspection object 1 with a constant pressing force,
Similar to the first embodiment described above, the inspection target part 3 is identified and detected based on the difference in the amount of reflected light, and since the reflecting member 8 serving as the background does not rotate, the amount of reflected light from the reflecting member 8 is a constant value, therefore,
More stable identifiability can be obtained. In addition,
In this case, since the reflective member 8 is worn out by sliding, it is desirable to use a material with excellent wear resistance such as Teflon.

〔Effect of the invention〕

As explained above, in the surface defect inspection method of the present invention, a member having a different reflectance from the inspection target part is brought into contact with the outer edge of the inspection target part, and the inspection target part is detected by the difference in the amount of reflected light from both. clearly separated detection,
Defects can be detected with stable accuracy even for objects to be inspected with complex shapes, and the method of the present invention takes into consideration the contrast between the reflectance of the inspected part and the materials with different reflectances. It has the feature that it can be applied to objects to be inspected with any reflectance depending on the selection.

[Brief explanation of drawings]

Fig. 1 is a schematic plan view showing a first embodiment of the method of the present invention, Fig. 2 is a schematic front view of the same, Fig. 3 is a schematic plan view with the same part cut away, and Fig. 4 is the amount of reflected light in the same embodiment. FIG. 5 is a schematic plan view showing the second embodiment, FIG. 6 is a schematic front view thereof, FIG. 7 is a perspective view showing a method for inspecting a sheet-like object to be inspected, and FIG. 8 is a schematic plan view showing the second embodiment. FIG. 9 is a schematic plan view showing an example of the conventional method, FIG. 10 is a schematic front view of the same, and FIG. 11 is a graph of the amount of reflected light in the method. 1...Object to be inspected, 3...Part to be inspected, 4, 8...
... Reflection member, 5 ... Coil spring, 7 ... Outer peripheral edge.

Claims (1)

[Claims] 1 In a non-contact optical surface defect inspection method that detects defects by electrically detecting and measuring the amount of reflected light from the inspection target part of the inspection object using an image sensor such as a television camera, A rotating object is rotated, and a member having a reflectance different from that of the object to be inspected is elastically disposed and brought into rotational contact or sliding contact with the outer edge of a portion to be inspected of the rotating object to be inspected, and the amount of reflected light from the contact portion is adjusted. A surface defect inspection method characterized by identifying a portion to be inspected by detecting a difference.