JP2011027577A - Device for inspecting glossy cylindrical surface shape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To overcome the problem in a conventional shape inspection method that uses the rotation of a cylindrical surface with specular reflection, wherein the method can not be applied to the cylindrical surface of a continuum or to an unrotatable cylindrical surface. <P>SOLUTION: The device for inspecting a glossy cylindrical surface shape includes: an illumination system with a circular light source, a condenser lens and a gate-type mirror; and a detection system with a gate-type mirror, an imaging mirror and a two-dimensional camera. The gate-type mirror is arranged so that the optical axes of the condenser lens and the imaging lens and the central axis of the cylindrical surface to be measured are coincided with each other by the gate-type mirror. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

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 Surface shape inspection is performed by the method.

Patent 3429966 Patent 3099462

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. Therefore, the present invention provides a glossy cylindrical surface shape that can measure the surface shape even when the cylindrical portion cannot be rotated, or even if the cylindrical portion is very long or continuous, and the surface is glossy or mirror surface. An object is to provide an inspection device.

In order to solve the above problems, an illumination system including an arc-shaped light source, a condensing lens, and a portal mirror, and a detection system including a portal mirror, an imaging lens, and a two-dimensional image sensor are provided. The glossy cylindrical surface shape inspection apparatus is characterized in that the portal mirror is arranged so that the optical axis of the image lens and the central axis of the measurement target cylindrical surface are substantially the same through the portal mirror.

  Further, the glossy cylindrical surface shape inspection apparatus is characterized in that image processing for converting the image of the two-dimensional image sensor into a numerical value by the distance from the center of the arc is performed, and good / bad determination is performed based on the numerical value.

  Also, the glossy cylindrical surface shape inspection apparatus is characterized in that the arc-shaped light source includes a semiconductor laser, a collimation lens, and two axicon lenses.

  By configuring as above, glossy cylindrical surface shape that can measure the surface shape 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 An inspection device can be provided.

It is a block diagram of the 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 of the 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 glossy cylindrical surface shape inspection apparatus in Example 2 of this invention.

FIG. 1 shows a configuration diagram of a glossy cylindrical surface shape inspection apparatus in Embodiment 1 of the present invention. 1 is a semiconductor laser, 2 is a collimator lens, 3 and 4 are conical axicon lenses, 5 is a light shielding plate, 6 is a condenser lens, 7 is a portal mirror, 8 is a cylindrical surface to be measured, and 9 is a portal mirror Reference numerals 10 and 11 denote imaging lenses, and reference numeral 12 denotes a two-dimensional image sensor.

The light emitted from the semiconductor laser 1 is converted into substantially parallel light by the collimator lens 2 and enters the axicon lens 3. The axicon lens is a conical lens, and the emitted light spreads in an arc shape. This is put into the axicon lens 4 and converted again into a substantially parallel arc-shaped light.

Here, the light that is not reflected by the gate mirror 7 is shielded by the light shielding plate 5. The arc-shaped light that is not shielded is condensed by the condenser lens 6. 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 always incident perpendicularly to a cylindrical surface having the same axis because it converges in the optical axis direction.

The light reflected from the measurement target cylindrical surface is folded back by the portal mirror 9 and is incident on the two-dimensional image sensor 12 by the imaging lenses 10 and 11. Again, when folded by the portal mirror 9, the optical axes of the imaging lenses 10 and 11 are configured to coincide with the cylindrical axis of the cylindrical surface 8 to be measured. Since the two-dimensional image sensor 12 is placed at a position conjugate to the reflection point of the measurement target cylindrical surface 8 and the imaging lenses 10 and 11, an arc conjugate to the reflected arc light of the measurement target cylindrical surface 8 is placed on the two-dimensional image sensor. 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 12a on the two-dimensional image sensor, so that 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 12 denotes a two-dimensional image sensor on which imaging light I conjugate with the reflection point of the measurement target cylindrical surface 8 is projected. As described in FIG. 2, since this optical system is rotationally symmetric with respect to the optical axis, if the cylindrical surface is perfect, the two-dimensional image sensor 12 also rotates about the central coordinate O that intersects the optical axis. Symmetric arc-shaped imaging light I is formed.

If there is a change in the measurement target cylindrical surface, the change is converted into a change in imaging light as described with reference to FIG. 2, but the change is on a straight line including the center coordinate O on the two-dimensional image sensor 12. Will fluctuate. Therefore, when the unevenness of the cylindrical surface 8 to be measured is read from the main image, a straight line with an arbitrary angle θ is considered from the center coordinate O, the intersection of the straight line and the imaging light I is obtained, and the distance R from the central coordinate O is obtained. Will be asked. That is, image processing is performed in which data of the polar coordinate system (θ, R) centered on the point O is calculated. If the calculated (θ, R) coordinates do not fall within the expected range, it is determined that the shape is defective.

FIG. 4 shows a configuration diagram of a glossy cylindrical surface shape inspection apparatus in Embodiment 2 of the present invention. 21 is a lamp light source, 22 is a light-shielding plate having an arc-shaped slit, 23 is a collimation lens, 5B is a light-shielding plate through which arc-shaped light is transmitted, and 6 and the like are the same as in the first embodiment.

The light emitted from the lamp light source 21 is shielded by the light shielding plate 22, but only the portion passes because the slit on the arc is cut. The light that has passed through the slit on the arc is converted into substantially parallel light by the collimation lens 23.

Here, the light that cannot be reflected by the portal mirror 7 is blocked by the light blocking plate 5B. In the first embodiment, the original beam has no central portion. However, in the second embodiment, since the central portion is also light, the central portion is also shielded. The arc-shaped light that is not shielded is condensed by the condenser lens 6. In the middle of the light collection, it is folded back by the gate-shaped mirror 7 and condensed on the surface of the measurement target cylindrical surface 8 in an arc shape. Subsequent functions are the same as those 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. 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.

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, the surface which has been difficult to inspect until now can be inspected for a specular continuous cylindrical body, and can be used for measurement on a line. Further, the present invention can be applied to an object that cannot be rotated such as a flat end. Thus, since it is possible to inspect a cylindrical body that has been difficult until now, it is very useful in industry.

DESCRIPTION OF SYMBOLS 1 Semiconductor laser 2 Collimator lens 3, 4 Axicon lens 5 Light shielding plate 6 Condensing lens 7 Portal mirror 8 Cylindrical mirror surface 9 Portal mirror 10, 11 Imaging lens 12 Two-dimensional image sensor 21 Lamp light source 22 Arc-shaped slit With light shielding plate 23 Collimation lens O Center coordinates I Imaged light image

Claims (3)

An illumination system with an arc-shaped light source, a condenser lens, and a portal mirror, and a detection system with a portal mirror, an imaging lens, and a two-dimensional camera are provided. A glossy cylindrical surface shape inspection apparatus, wherein a gate-type mirror is arranged so that a central axis of the cylindrical surface is the same through a gate-type mirror. 2. The glossy cylindrical surface shape inspection apparatus according to claim 1, wherein image processing for converting the image of the two-dimensional camera into a numerical value based on the distance from the optical axis light spot coordinate is performed, and whether the quality is good or bad is determined based on the numerical value. 3. The glossy cylindrical surface shape inspection apparatus according to claim 1, wherein the arc-shaped light source includes a semiconductor laser, a collimation lens, and two axicon lenses.

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