JPH10282006A - Cylindrical surface defect inspection device - Google Patents

Abstract

(57) [Problem] To provide a cylindrical defect inspection apparatus capable of accurately detecting a defect regardless of a state of a defect on a cylindrical surface of a cylindrical inspection object. SOLUTION: A laser beam is irradiated at a certain angle in a circumferential direction of a cylindrical surface 1a of a cylindrical inspection object 1, and reflected light is received by a light receiving sensor 9. The inspection object 1 is moved in the axial direction A of the inspection object 1 in synchronization with the circumferential scanning of the cylindrical surface 1a of the inspection object 1. Thereby, the cylindrical surface 1a of the inspection object 1
Is irradiated with a laser beam at a fixed angle, and the cylindrical surface 1a of the inspection object 1 is spirally scanned. When the amount of reflected light is lower than a predetermined value, it is determined that the inspection object has a defect.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting a surface defect of a cylindrical body, and more particularly, to an apparatus for inspecting a cylindrical surface of an object to be inspected by irradiating the surface with an inspection light and detecting the reflected light. The present invention relates to a structure of a cylindrical defect inspection apparatus that detects a defect on a cylindrical surface of an inspection object.

[0002]

2. Description of the Related Art As a prior art relating to a cylindrical surface defect inspection apparatus, there is, for example, one disclosed in Japanese Patent Application Laid-Open No. Hei 6-118007. In this publication, a defect on the surface of the inspection object is detected by irradiating the inspection object in a cylindrical body with slit light and imaging the slit image.

[0003]

However, Japanese Patent Application Laid-Open No.
In the method disclosed in JP-A-118007, since the optical positional relationship among the inspection object, the illumination device, and the light receiving device differs depending on the axial position of the inspection object, accurate inspection of the entire inspection object cannot be performed. In addition, if there is no mechanism corresponding to the change in the diameter of the inspection object, and if the adjustment mechanism is added,
It is inconvenient because it is necessary to adjust the mounting angle of the lighting device, light receiving sensor, etc. with respect to the circumferential direction of the inspection object.
Furthermore, accurate inspection requires the mounting accuracy of the inspection object, and is difficult to operate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and is capable of accurately detecting a defect on a cylindrical surface of a cylindrical inspection object regardless of the state of the defect on the surface. The purpose of the present invention is to provide a defect inspection apparatus.

[0005]

According to a first aspect of the present invention, an inspection light is applied to a cylindrical surface of a cylindrical object to be inspected to detect its reflected light, and the reflected light data detected continuously is obtained. By performing the process, in the cylindrical surface defect inspection apparatus for detecting a defect on the surface of the inspection object cylinder, a constant while moving in the circumferential direction of the cylindrical surface relative to the cylindrical surface of the cylindrical inspection object An inspection light irradiating unit that irradiates the inspection light at an incident angle; and an inspection object moving unit that moves the inspection object in an axial direction of the inspection object, wherein the inspection light irradiation unit and the inspection object In cooperation with a moving means, the inspection light spirally scans the surface of the inspection object cylinder to detect a defect on the surface of the inspection object cylinder. Accurate chipping regardless of where the defect is on the cylindrical surface It is obtained to be able to detect the.

According to a second aspect of the present invention, in the first aspect of the present invention, the inspection light irradiating means is responsive to the diameter of the inspection object such that a spot of the inspection light is formed on the surface of the inspection object cylinder. And an optical path length adjusting means for adjusting the optical path length of the optical system of the inspection light irradiating means, so that the inspection light irradiating means can correspond to inspection objects having various diameters.

According to a third aspect of the present invention, in accordance with the first or second aspect of the present invention, the reflection light is disposed at an image forming position of the reflected light with respect to the reference surface of the inspection object cylinder and reflected on the reference inspection object cylinder surface. A light-receiving sensor that detects the amount of defocus between the light and the reflected light with respect to the surface of the inspection object cylindrical surface of the inspection object, and based on the amount of defocus detected by the light reception sensor, It is characterized by having inspection object quality determination means for determining quality.
In this case, the quality of the inspection object can be determined according to the state of the irregularities on the surface of the inspection object cylinder.

According to a fourth aspect of the present invention, in the third aspect of the invention, the position of the optical system of the inspection light irradiating means is corrected so as to correct the defocus based on the defocus amount detected by the light receiving sensor. A defocus correcting means for correcting, an optical system displacement detecting means for detecting the displacement of the optical system corrected by the defocus correcting means, and a displacement detected by the optical system displacement detecting means. An inspection object position correction unit that corrects the positional deviation of the inspection object, wherein the inspection object quality determination unit determines the inspection object based on the displacement detected by the optical system displacement detection unit. This is characterized in that the quality of the object to be inspected is corrected by correcting the positional deviation of the object to be inspected.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the construction of a main part of a cylindrical body surface defect inspection apparatus according to an embodiment of the present invention. In the drawing, reference numeral 1 denotes an inspection object, and 1a denotes an inspection object 1. Cylindrical surface,
2 is a laser oscillator, 3 is a half mirror, 4 is a lens, 5
Is a rotating mirror, 6 and 7 are conical mirrors, 8 is a pinhole,
9 is a light receiving sensor, A is a moving direction of the inspection object 1, and B is an image forming position of the reflected light.

Referring to FIG. 1, first, a mechanism for irradiating a laser beam at a fixed angle in the circumferential direction of a cylindrical inspection object 1 and receiving the reflected light by a light receiving sensor 9 will be described.

The laser light emitted from the laser oscillator 2 passes through the half mirror 3 and the lens 4 and enters the rotating mirror 5. The laser beam deflected by the rotating mirror 5 forms a spot on the cylindrical surface 1 a of the inspection object 1 via the conical mirror 6 and the conical mirror 7. The reflected light from the cylindrical surface 1a enters the rotating mirror 5 via the conical mirror 7 and the conical mirror 6.

When the cylindrical surface 1a of the inspection object 1 is at the reference position in the diameter direction of the inspection object 1, that is, when the cylindrical surface 1a of the inspection object 1 has no irregularities, the reflected light incident on the rotating mirror 5 Is focused on the position B by the lens 4 and the half mirror 3, passes through the pinhole 8, and enters the light receiving sensor 9. At this time, the light receiving amount of the light receiving sensor 9 takes a maximum value.

When the cylindrical surface 1a of the inspection object 1 is not at the reference position in the diameter direction of the inspection object 1, that is, when the cylindrical surface 1a of the inspection object 1 has irregularities, the reflected light incident on the rotating mirror 5 Is formed before or after the position B by the lens 4 and the half mirror 3. As a result, the amount of reflected light that passes through the pinhole 8 and enters the light receiving sensor 9 is reduced as compared with the case where the cylindrical surface 1a of the inspection object 1 is at the reference position in the diameter direction of the inspection object 1.

Here, when the test object 1 is fixed without moving in the axial direction, the test object 1 is emitted from the laser oscillator 2 and is rotated on the same circumference of the cylindrical surface 1a of the test object 1 by the rotation of the rotating mirror 5. The amount of light received by the light receiving sensor 9 when the reflected light of the laser beam scanned at a fixed incident angle is received by the light receiving sensor 9 is large when the cylindrical surface 1a of the inspection object 1 has no irregularities, and is small when the cylindrical surface 1a has irregularities.

According to the first aspect of the present invention, as shown in FIG.
In a mechanism in which a laser beam is irradiated at a fixed angle in the circumferential direction of the cylindrical surface 1a of the inspection object 1 and the reflected light is received by the light receiving sensor 9, the mechanism is synchronized with the scanning of the inspection object 1 in the circumferential direction. By moving the inspection object 1 in the axial direction A of the inspection object 1, the cylindrical surface 1a of the inspection object 1 is irradiated with laser light at a certain angle, and the cylindrical surface 1a of the inspection object 1 is spirally formed. It can be scanned, and the cylindrical surface 1 of the inspection object 1
a The entire surface is irradiated with a laser beam at a fixed incident angle, and the amount of reflected light is measured by the light receiving sensor 9. If the amount of reflected light becomes lower than a predetermined value, it is determined that the inspection object has a defect. This is to determine.

FIG. 2 is a view showing the construction of a main part of a cylindrical surface defect inspection apparatus according to another embodiment of the present invention. In FIG. The same reference numerals as those in the embodiment shown in FIG. 1 are assigned to the portions having the same functions as those in the embodiment shown in FIG.

According to a second aspect of the present invention, as shown in FIG.
1 is obtained by replacing the conical mirror 7 of the embodiment shown in FIG. 1 with a conical half mirror 10 and a donut-shaped mirror 11 which can move in the axial direction A of the test object 1. When ΔD changes, the donut mirror 11
Is moved in the axial direction A of the test object 1 by ΔX = ΔD / 2 so that the optical path length can be kept constant. As a result, the diameter D of the target test object 1 becomes smaller. Even if it changes, an accurate inspection can be performed.

FIG. 3 is a block diagram of a main part for explaining another embodiment of a cylindrical surface defect inspection apparatus according to the present invention. In FIG. 3, reference numeral 12 denotes a four-division photodiode, and a, b, c, and d denote the same. In the divided areas of the four-division photodiode 12, other portions that perform the same operations as in the embodiment shown in FIG. 1 or 2 are denoted by the same reference numerals as those in the embodiment shown in FIG.

According to a third aspect of the present invention, as shown in FIG. 3A, the reflected light of the inspection light which has formed the spot on the inspection object 1 has the cylindrical surface 1a of the inspection object 1 at the reference position. In this case, the spot shape is detected by the four-division photodiode 12 placed at the position B where the reflected light forms an image, and the spot shape at the four-division photodiode 12 according to the position of the inspection object 1 as shown in FIG. As a result, the unevenness of the cylindrical surface 1a of the inspection object 1 is reduced by the following focus error {(Sa + Sd)-(Sb + Sc)} / {(Sa + S)
d) − (Sb + Sc)｝ (where, Sa, Sb, Sc,
Sd respectively represents the spot area on the divided areas a, b, c, and d).
The threshold level for detecting a defect is set according to the case where the cylindrical surface 1a of the inspection object 1 is convex or concave, so that accurate defect detection can be performed.

FIG. 4 is a block diagram of a main part for explaining another embodiment of the cylindrical surface defect inspection apparatus according to the present invention. In FIG. 4, reference numeral 13 denotes a motor, 14 denotes a displacement meter, and FIGS. Parts having the same functions as those of the embodiment shown in FIG. 3 are denoted by the same reference numerals as those of the embodiment shown in FIGS.

According to a fourth aspect of the present invention, as shown in FIG.
The focus error obtained from the output of the four-division photodiode 12 is fed back to the motor 13 to adjust the position of the lens 4 so that the focus error becomes 0. At this time, the displacement of the lens 4 detected by the displacement meter 14 The unevenness of the cylindrical surface 1a of the inspection object 1 is determined, and by determining this, a defect of the inspection object 1 can be detected.

According to the present invention, it is possible to accurately detect the irregularities of the cylindrical surface 1a of the inspection object 1 over a wider range than in the invention of the third aspect, and thereby, the mounting position of the inspection object 1 Even if there is some deviation, the position of the inspection object 1 can be corrected and a more accurate defect can be detected.

[0023]

According to the first aspect of the present invention, inspection light is applied to the surface of a cylindrical object to be inspected to detect the reflected light, and the reflected light data detected continuously is processed. A cylindrical surface defect inspection apparatus for detecting a defect on the surface of the inspection object cylinder, wherein the cylindrical surface of the inspection object is moved in a circumferential direction of the cylinder surface with respect to the cylindrical surface of the inspection object at a constant incident angle. Inspection light irradiation means for irradiating inspection light, and an inspection object moving means for moving the inspection object in the axial direction of the inspection object, wherein the inspection light irradiation means and the inspection object movement means By cooperating, the inspection light spirally scans the surface of the inspection object cylinder to detect a defect on the surface of the inspection object cylinder. Regardless, a defect can be accurately detected.

According to a second aspect of the present invention, in the first aspect of the present invention, the inspection light irradiating means adjusts the diameter of the inspection object so that a spot of the inspection light is formed on the surface of the inspection object cylinder. Since the optical path length adjusting means for adjusting the optical path length of the optical system of the inspection light irradiating means is provided, it is possible to cope with inspection objects having various diameters.

According to a third aspect of the present invention, in accordance with the first or second aspect, the reflection light is disposed at an image forming position of the reflected light with respect to the reference surface of the inspection object cylinder and reflected on the reference surface of the inspection object cylinder. A light-receiving sensor that detects the amount of defocus between the light and the reflected light with respect to the surface of the inspection object cylindrical surface of the inspection object, and based on the amount of defocus detected by the light reception sensor, Since the inspection object quality determination means for determining the quality is provided, it is possible to determine the quality of the inspection object according to the state of the irregularities on the cylindrical surface of the inspection object.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the position of the optical system of the inspection light irradiating means is adjusted so as to correct the defocus based on the defocus amount detected by the light receiving sensor. A defocus correcting means for correcting, an optical system displacement detecting means for detecting the displacement of the optical system corrected by the defocus correcting means, and a displacement detected by the optical system displacement detecting means. An inspection object position correction unit that corrects the positional deviation of the inspection object, wherein the inspection object quality determination unit determines the inspection object based on the displacement detected by the optical system displacement detection unit. Is determined, the quality of the inspection object can be determined regardless of the accuracy of the mounting position of the inspection object.

[Brief description of the drawings]

FIG. 1 is a main part configuration diagram for explaining an embodiment of a cylindrical surface defect inspection apparatus according to the present invention.

FIG. 2 is a main part configuration diagram for explaining another embodiment of the cylindrical body surface defect inspection apparatus according to the present invention.

FIG. 3 is a main part configuration diagram for explaining another embodiment of a cylindrical body surface defect inspection apparatus according to the present invention.

FIG. 4 is a main part configuration diagram for explaining another embodiment of a cylindrical body surface defect inspection apparatus according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Inspection object, 1a ... Cylindrical surface of the inspection object 1, 2 ... Laser oscillator, 3 ... Half mirror, 4 ... Lens, 5 ... Rotating mirror, 6, 7 ... Conical mirror, 8 ... Pinhole, 9 ... Light reception Sensor: 10: conical half mirror, 11: donut-shaped mirror, 12: quadrant photodiode, 13: motor, 1
4: Displacement meter, A: Moving direction of inspection object 1, B: Image forming position of reflected light, D: Diameter of inspection object 1, a, b, c, d: 4
A divided area of the divided photodiode 12.

Claims (4)

[Claims] 1. A method of irradiating inspection light on a cylindrical surface of a cylindrical object to be inspected to detect reflected light thereof, and processing the reflected light data detected continuously, thereby obtaining a surface of the cylindrical object to be inspected. In the inspection apparatus for inspecting a surface defect of a cylindrical body, the inspection light irradiates the inspection light at a certain incident angle while moving in a circumferential direction of the cylindrical surface of the cylindrical inspection object. Irradiation means, having an inspection object moving means for moving the inspection object in the axial direction of the inspection object,
The inspection light irradiation unit and the inspection object moving unit cooperate with each other, whereby the inspection light spirally scans the inspection object cylindrical surface to detect a defect on the inspection object cylindrical surface. Characteristic cylindrical surface defect inspection device. 2. The cylindrical surface defect inspection apparatus according to claim 1, wherein the inspection light irradiating means is responsive to a diameter of the inspection object such that a spot of the inspection light is formed on a surface of the inspection object cylinder. And a light path length adjusting means for adjusting an optical path length of an optical system of the inspection light irradiation means. 3. The cylindrical surface inspection apparatus according to claim 1, wherein said cylindrical surface inspection apparatus is disposed at an image forming position of reflected light with respect to a reference cylindrical surface of the inspection object. And a light-receiving sensor for detecting the amount of defocus between reflected light with respect to the object and light reflected from the surface of the inspection object with respect to the cylindrical surface of the inspection object. An inspection apparatus for inspecting the surface of a cylindrical body, comprising a means for judging the quality of an object to be inspected for judging the quality of an object. 4. The inspection system according to claim 3, wherein the optical system of the inspection light irradiation means corrects the defocus based on the defocus amount detected by the light receiving sensor. Defocus correcting means for correcting the position, optical system displacement detecting means for detecting the displacement of the optical system corrected by the defocus correcting means, and the displacement detected by the optical system displacement detecting means. Inspection object position correction means for correcting the positional deviation of the inspection object based on the displacement of the inspection object based on the displacement amount detected by the optical system displacement amount detecting means. An inspection apparatus for inspecting a surface defect of a cylindrical body, which determines whether or not an inspection object is good.