JP2016205972A - Scan type glossy cylindrical-surface-shape inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glossy cylindrical-surface-shape inspection device capable of inspecting not only the surface shape but also a scratch and dirt even when a cylindrical part cannot rotate, the cylindrical part is extremely long or continuous, or the surface is glossy or a mirror plane.SOLUTION: The inspection device includes: a circular-arc-shaped scan light source having a semiconductor laser 1, a collimation lens 2, a wedge-shaped rotary prism 3, or an oblique rotary mirror; an illumination system having a condensing lens 6 and a gate-type mirror 7; and a detection system having a gate-type mirror 9, an image formation lens 10, and a two-dimensional PSD 13. The gate-type mirrors 7 and 9 are arranged so that the optical axis of the condensing lens 6 and image formation lens 10 is the same as the central axis of a cylindrical surface 8 to be measured via the gate-type mirrors 7 and 9.SELECTED DRAWING: Figure 1

Description

The present invention relates to a glossy cylindrical surface shape inspection apparatus for inspecting the shape of a cylindrical object having a glossy surface or mirror surface on the outside.

  Today, there are cylindrical objects with glossy surfaces composed of metal, plastic, glass, etc., such as rolls for transporting paper and film, or photosensitive rolls used for copying, etc. A method of measuring the cut surface by scanning or making a line image in the axial direction of the cylindrical surface, for example, Patent Document 1, or a method of measuring by moving a conical mirror or the like in the axial direction of the cylindrical surface, for example, Patent Document 2 The surface shape is inspected by a method, or a method in which a light beam on an arc is applied to a cylindrical surface, for example, the method of Patent Document 3.

Patent 3429966 Patent 3099462 Patent 5294081

  The method of measuring the cut surface by scanning or making a line image in the axial direction of the cylindrical surface is based on the premise that the cylindrical surface is rotated, so it was not possible to inspect non-rotatable objects, such as the surface of a continuous molded product . Similarly, an object that is not rotationally symmetric, for example, a cylindrical surface portion of an object having a cylindrical shape on the plate, could not be measured. Further, in the method of measuring by moving a conical mirror or the like in the axial direction of the cylindrical surface, it is not possible to measure an object that is very long or continuous in the axial direction of the cylindrical surface, such as a continuously molded resin pipe. In addition, fine scratches and the like could not be measured by the method of applying a light beam on an arc. Therefore, even if the cylindrical portion cannot be rotated, the cylindrical portion is very long or continuous, and even if the surface is glossy or mirror surface, not only the surface shape but also scratches and dirt An object is to provide a glossy cylindrical surface shape inspection device capable of inspection.

In order to solve the above problems, a scanning system including a light source, a collimator lens, a rotating light scanner, a condensing lens, and a portal mirror, a portal mirror, an imaging lens, a rotating light scanner, a condensing lens, and a two-dimensional lens A detection system having a PSD is provided, and the portal mirror is arranged so that the optical axis of the condenser lens and the imaging lens and the central axis of the measurement target cylindrical surface are substantially the same through the portal mirror. A scanning glossy cylindrical surface shape inspection apparatus was obtained.

  In addition, the scanning glossy cylindrical surface shape inspection apparatus is characterized in that a signal processing for converting a two-dimensional PSD signal into a numerical value in the direction of rotation of the optical scanner is performed, and good / bad determination is performed based on the numerical value.

  In addition, a scanning type glossy cylindrical surface shape inspection apparatus is characterized in that the rotating light scanner is a wedge-shaped rotating prism.

  By configuring as described above, surface shape measurement and inspection of scratches and dirt can be performed even if it is impossible to rotate, no matter how long a cylindrical object is, and even if the surface is a perfect glossy surface or mirror surface. A possible scanning type glossy cylindrical surface shape inspection apparatus can be provided.

It is a block diagram of the scanning glossy cylindrical surface shape inspection apparatus in Example 1 of this invention. It is sectional drawing of the optical system which abbreviate | omitted mirror folding | turning of the scanning glossy cylindrical surface shape inspection apparatus in Example 1 of this invention. It is a figure explaining the image formation image and process in Example 1 of this invention. It is a block diagram of the scanning type glossy cylindrical surface shape inspection apparatus in Example 2 of this invention.

FIG. 1 shows a configuration diagram of a scanning glossy cylindrical surface shape inspection apparatus in Embodiment 1 of the present invention. 1 is a semiconductor laser, 2 is a collimator lens, 3 is a wedge-shaped rotating prism, 5 is a light-shielding plate, 6 is a condenser lens, 7 is a portal mirror, 8 is a cylindrical surface to be measured, 9 is a portal mirror, The imaging lenses 1 and 11 are wedge-shaped rotating prisms, the imaging lenses 2 and 13 are two-dimensional PSDs.

The light emitted from the semiconductor laser 1 is converted into substantially parallel light by the collimator lens 2 and enters the wedge-shaped rotating prism 3. The light emitted from the wedge-shaped rotating prism 3 is bent toward the thicker wedge. Since the wedge-shaped rotating prism 3 is rotating, the emitted light is scanned in an arc shape.

The light scanned in the arc shape is collected by the condenser lens 6. Here, the light that is not reflected by the gate mirror 7 is shielded by the light shielding plate 5. In the middle of the light collection, it is folded back by the gate-shaped mirror 7 and is collected in a circular arc shape on the surface of the measurement target cylindrical surface 8. The gate-type mirror is a normal mirror, but a part that mechanically interferes with the measurement object is cut out.

Here, the optical axis of the condenser lens is configured to coincide with the cylindrical axis of the cylindrical surface 8 to be measured when it is folded back by the portal mirror 7. Considering a cross-section cut by a plane perpendicular to the optical axis, the light exiting the condenser lens is collected in the direction of the optical axis, so that the cylindrical surface having the same axis is incident and reflected within the plane including the axis. Will do.

The light reflected from the cylindrical surface to be measured is folded back by the portal mirror 9 and is incident on the wedge-shaped rotating prism 11 by the imaging lens 10. Here, the wedge-shaped rotating prism 11 is synchronized with the wedge-shaped rotating prism 3 and rotates in the reverse direction. As a result, the light emitted from the wedge-shaped rotating prism 11 is converted into a direction substantially parallel to the optical axis, and is incident on the two-dimensional PSD 13 by the condenser lens 12. Also here, the optical axis of the imaging lens 10 and the condensing lens 12 is configured to coincide with the cylindrical axis of the measurement target cylindrical surface 8 when folded by the portal mirror 9. Since the two-dimensional PSD 13 is placed at a position conjugate to the reflection point of the measurement target cylindrical surface 8 and the imaging lens 10 and the condenser lens 12, a point conjugate to the reflection point on the measurement target cylindrical surface 8 is present on the two-dimensional PSD. An image will appear.

FIG. 2 shows a diagram of an optical system in which mirror folding of the glossy cylindrical surface shape inspection apparatus in the embodiment of the present invention is omitted. Here, the folding mirror is omitted, and the optical axis of the optical system and the axis of the cylindrical surface to be measured are actually matched. The function of each component is as described in FIG. 1, and light travels as shown in this figure in any cross section including the optical axis except for the portion that cannot be reflected by the portal mirror.

When the measurement target cylindrical surface fluctuates as indicated by 8a, the reflected light travels as indicated by a broken line and reaches the portion 13a on the two-dimensional PSD, and the fluctuation can be detected. Since any change in the cross section including the optical axis can be detected in this way, the shape of the glossy cylindrical surface can be measured.

FIG. 3 is a diagram for explaining a formed image and processing in the embodiment of the present invention. Reference numeral 13 denotes a two-dimensional PSD on which imaging light I conjugate with the reflection point of the measurement target cylindrical surface 8 is projected. As described with reference to FIG. 2, since the present optical system is rotationally symmetric with respect to the optical axis, an imaging point is formed at the center coordinate O on the two-dimensional PSD 13 if the cylindrical surface is perfect.

If there is a variation in the measurement target cylindrical surface, the variation is converted into the imaging light variation 13a as described with reference to FIG. The fluctuation varies on a straight line including the center coordinate O on the two-dimensional PSD 13, but the direction is rotated by the rotation of the wedge-shaped rotating prism 11. Therefore, when the unevenness of the measurement target cylindrical surface 8 is read from the PSD signal, the distance R from the center coordinate O from the center coordinate O to the imaging light 13a in the rotation angle θ direction of the wedge-shaped rotating prism 11 is obtained. . When the calculated R does not fall within the planned range S, it is determined that the shape is defective. Since PSD can also measure the amount of light, it can be determined as defective if the amount of reflected light is below a certain level.

FIG. 4 shows a configuration diagram of a glossy cylindrical surface shape inspection apparatus in Embodiment 2 of the present invention. 3b is an oblique rotation mirror, 4 is a folding mirror, and the others are the same as in the first embodiment.

The light emitted from the semiconductor laser 1 is converted into substantially parallel light by the collimator lens 2 and enters the folding mirror 4. The light emitted from the folding mirror 4 travels upward on the same optical axis as the optical axis of the condenser lens 6 and enters the obliquely rotating mirror 3b. The oblique rotation mirror 3b reflects light inclined from the optical axis, and since it rotates, the reflected light is scanned in an arc shape.

The arc-shaped light is collected by the condenser lens 6. Thereafter, the light that is not reflected by the portal mirror 7 is shielded by the light shielding plate 5. Since light does not pass through the light shielding side, it is desirable that the mechanism for supporting the folding mirror 4 is also installed in the same direction as the light shielding plate 5. The light that has not been shielded is folded back by the portal mirror 7 and collected on the surface of the cylindrical surface 8 to be measured. The functions up to the imaging lens 10 are the same as those in the first embodiment.

Unlike the first embodiment, the light emitted from the imaging lens 10 enters the condenser lens 12 as it is and enters the two-dimensional PSD 13. In the first embodiment, light having no abnormality is incident on the center of the two-dimensional PSD 13, but in this embodiment, light having no abnormality draws an arc on the two-dimensional PSD 13. Therefore, although it is not suitable for measuring minute unevenness, this method can also be used when the unevenness to be measured is relatively large or the measurement of the amount of reflected light is main. In such a case, one-dimensional PSD can also be used. Note that the condensing lens 12 is omitted, and the function can be realized only by the imaging lens 10. Of course, it is also possible to measure minute irregularities by providing an obliquely rotating mirror that rotates in reverse in synchronization with the scanning side as in the first embodiment.

As described above, in any of the embodiments, even if the cylindrical surface is a perfect specular reflection surface, the cylindrical surface cannot be rotated, or the cylindrical surface is a continuous object. The surface shape can be measured. Further, since measurement is performed by scanning with a single beam, a difference in partial reflectance can be detected with high sensitivity. In any embodiment, if two sets are used, it is possible to inspect cylindrical objects in a 360 degree range. In addition, the cylindrical surface of the object is optimal, but the present invention is not limited to this, and inspection of a spherical body or a polygonal mirror reflector can be performed by this method. It is also possible to omit the light shielding plates 5 and 5B and to have a similar function in the portal mirror. The condensing lens 6 and the imaging lens 10 can be replaced with a parabolic mirror having the same function.

As described above, according to the present embodiment, even if the cylindrical surface is a perfect specular reflection surface, the cylindrical surface cannot be rotated, or the cylindrical surface is a continuous object, Since the surface shape can be measured, and the difference in partial reflectance can be detected with high sensitivity, the irregularities and scratches of the continuous cylindrical body whose surface has been difficult to inspect until now, Inspection of cracks, dirt, etc. is possible and can be used for measurement on the line. Further, the present invention can be applied to an object that cannot be rotated such as a flat end. As described above, since it is possible to inspect a glossy cylindrical body, which has been difficult until now, it is very useful in industry.

DESCRIPTION OF SYMBOLS 1 Semiconductor laser 2 Collimator lens 3 Wedge-shaped rotating prism 3b Oblique rotating mirror 4 Folding mirror 5 Light-shielding plate 6 Condensing lens 7 Portal mirror 8 Measuring object cylindrical surface 9 Gate-shaped mirror 10 Imaging lens 11 Wedge-shaped rotating prism 12 Condensing lens 13 2D PSD
23 Collimation lens O Two-dimensional PSD center coordinate 13a Imaging light image S Tolerable range

Claims (2)

Semiconductor laser, collimation lens, arcuate scanning light source with wedge-shaped rotating prism or obliquely rotating mirror, condenser system, illumination system with portal mirror, and detection system with portal mirror, imaging lens, and two-dimensional PSD A scanning-type glossy cylindrical surface shape inspection, characterized in that the gate-type mirror is arranged so that the optical axis of the condenser lens and the imaging lens and the central axis of the measurement target cylindrical surface are the same via the gate-type mirror apparatus. 2. The glossy cylindrical surface shape inspection apparatus according to claim 1, further comprising a wedge-shaped rotating prism or an oblique rotating mirror that rotates in synchronization with the scanning side behind the light-receiving-side imaging lens.

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