JPH0594517A - Image input device for optical inspection instrument - Google Patents

Abstract

PURPOSE:To reduce the number of parts, to easily obtain the parts, to reduce the size and weight of a device, to improve vibration-proof property and lighting efficiency, and to attain safe and stabilized inspection. CONSTITUTION:This image input device is provided with plural image pickup devices 3, 4 for photographing a mirror face-like object to be inspected such as a compact disk having a non-mirror face part 1a on its center part and an illuminating device 6 with a diffusion plate 14 to light up the object to be inspected and respective devices 3, 4 are fixed in the observation window 1a of the plate 14 so that their optical axes 3b, 4b are inclined from the object only by angle theta. The object is included in the focusing point range of the lenses 3a, 4a of the devices 3, 4 to prevent reflected images from the devices 3, 4 from being projected to the mirror face part 1b of the object 1 photographing by the devices 3, 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mirror-like inspected object having a mirror surface portion, for example, a mirror-finished surface state of a compact disc or the like, more specifically, a character written on the surface,
The present invention relates to an image input device of an optical inspection device when inspecting a printed state of a figure or the like.

[0002]

2. Description of the Related Art Generally, in the case of a compact disc or the like,
In order to display the recorded contents, the manufacturer name, song name, performer name, etc. are printed on the mirror surface. An optical inspection device is used to inspect whether or not this printing condition is defective, but since the surface of the compact disc is usually mirror-finished by aluminum deposition, it reflects light rays like a mirror. However, since the printed characters and the like are identified by this reflective surface, it is difficult to illuminate them, and when the image pickup device is arranged vertically above the compact disc, the image pickup device itself is reflected. In order to solve this, the present applicant has already proposed an image input device for an optical inspection device as shown in FIG. 5 (Japanese Patent Application No. 2-266486).
issue).

In the image input device for this optical device, image pickup devices 16 and 17 are fixed to a support plate 15, and this image pickup device 1
A half mirror 18 is provided on the optical path between the compact disks 1 and 6 and the compact disk 1 on the inspection table 2. A black screen 19 is arranged on one side of the half mirror 18, and a white screen 20 is arranged on the other side of the half mirror 18, and the plane parallel rays from the illumination device 21 are irregularly reflected on the white screen 20. Then, the illumination light that has become uniform turbulent rays is projected onto the compact disc 1 through the half mirror 18, and the reflected light from the compact disc 1 is transmitted through the half mirror 18 and is incident on the imaging devices 16 and 17. There is.

[0004]

However, even the image input device for the optical inspection device having the above-mentioned structure has the following problems and problems. First, since the half mirror, which is a main component, is a special part, it is not easy to obtain and the manufacturing cost is high. Moreover, since the transmittance of the half mirror is less than 50%, the illumination efficiency is poor and the half image is taken by the imaging device. The image contrast is also low. Also,
Since the half mirror is provided so as to be tilted on the optical path and the white screen and the black screen are used, there is a problem that the entire image input device becomes large and heavy and the vibration resistance is poor. It is an object of the present invention to provide a small-sized image input device which does not have such problems and problems and can more stably perform surface inspection.

[0005]

As shown in FIG. 1, for example, an image input device for an optical inspection apparatus according to the present invention comprises a plurality of image pickup devices for photographing a mirror-like object to be inspected having a non-mirror surface portion at its center. In an image input device for an optical inspection device having the above-mentioned illuminating device with a diffuser plate for illuminating a specular object, the optical axis of the imaging device is tilted within the focusing range of the lens with respect to the specular object. It is attached to.

[0006]

In the image input device for the optical inspection apparatus of the present invention, the surface of the mirror-like object to be inspected which is uniformly illuminated by the illuminating device with the diffuser plate is photographed by each image pickup device. Since the lens is attached so as to be tilted within the focusing range of the inspection object, the reflection image of itself and another imaging device is reflected on the mirror surface portion of the inspection object that is imaged by one imaging device. Is avoiding. That is, the image of each imaging device projected on the mirror-like inspection object is incident on the mirror-like inspection object at a certain angle and is emitted at the same angle as this incident angle, so that each imaging device is self-contained. Also, it does not display the reflection image of another imaging device.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image input device for an optical inspection device of the present invention will be described below with reference to FIGS. Briefly, the image input device for an optical inspection apparatus of the present embodiment includes a plurality of image pickup devices 3 and 4 for photographing the specular object 1 having a non-specular surface portion 1a at the center, and the above-mentioned specular object. Inspection item 1
And an illuminating device 6 with a diffusing plate for illuminating each of the imaging devices 3 and 4, and the optical axes 3b and 4b of the lenses 3a and 4a of the imaging devices 3 and 4 are attached so as to be inclined in a focusing range with respect to the mirror-like inspection object 1. There is. This configuration will be described in more detail below.

The mirror-like inspection object 1 has a non-mirror-like portion 1 at the center.
It has a mirror surface portion 1b on the entire surface except a (clamping area), and in this embodiment, a compact disc having a diameter of 12 cm is used. Print characters, figures, etc. (hereinafter referred to as print characters) are attached to the upper surface of the mirror surface portion 1b of the compact disc 1, and the lower surface of the mirror surface portion 1b serves as a recording layer. In this embodiment, the compact disc 1 is placed on an inspection table 2 whose surface has been subjected to an antireflection treatment, and the image pickup devices 3 and 4 are arranged adjacently above it.

Charge-coupled device cameras (hereinafter referred to as CCD cameras) are used as the image pickup devices 3 and 4, and both cameras 3,
4 is minimized, and the optical axes 3b and 4b of the lenses 3a and 4a attached to the respective front parts are tilted by an angle θ with respect to the perpendicular V to the compact disc 1. This angle θ is preferably set to the minimum, but a characteristic of this arrangement is that the optical axes 3b and 4b of the CCD cameras 3 and 4 intersect at a point X. The images captured by the CCD cameras 3 and 4 are output to and processed by an image processing device 5 provided separately from the image input device for the optical inspection device of this embodiment.

The lighting device 6 with a diffuser plate includes an arm 7, a light base 9, an inverter ballast 10, and a round fluorescent lamp 1.
1, a fluorescent lamp holder 12, a camera holder 13, a diffusion plate 14 and the like. The arm 7 supports the entire image input device for the optical inspection device of this embodiment, and is made of aluminum extruded material, and one end of the arm 7 is fixed to columns 8 which are erected on a base (not shown). Has been done. The distance from the arm 7 to the compact disc 1 can be adjusted by adding the columns 8.

A disk-shaped light base 9 which is the base of the present apparatus is attached to the other end of the arm 7, and the inverter ballast 10 is concealed by the arm 7 on the upper surface of the light base 9. It is fixed. Further, a protrusion 9a is extended on the peripheral edge of the lower surface of the light base 9, and a round fluorescent lamp 11 (JIS standard FCL-20N) is supported inside the protrusion 9a via a fluorescent lamp supporter 12. The above-mentioned CCD cameras 3 and 4 are fixed to the center of the round fluorescent lamp 11 via a camera support 13. Then, the diffusion plate 14 described next is screwed to the outer periphery of the above-mentioned protrusion 9a.

The diffusion plate 14 is formed of an acrylic resin material to have an outer diameter substantially the same as that of the light base 9 described above, and a minimum necessary amount corresponding to the lenses 3a and 4a of the CCD cameras 3 and 4 described above is formed in the central portion of the lower surface. The small hole 14a is bored to secure the light entrance path, and the outer diameter of the upper end is reduced to form the stepped portion 14b. The reduced step portion 14b is fitted into the protrusion of the light base 9 and screwed.

Next, the operation of this embodiment having the above structure will be described. The inverter ballast 10 is operated to turn on the round fluorescent lamp 11 at a high frequency (21 kHz), and the round parallel rays following the shape of the round fluorescent lamp 11 are converted into uniform irregular rays by the diffuser plate 14 and diffused. The compact disc 1 on the inspection table 2 below the plate 14 is projected. Then, the compact disc 1 is photographed by each of the CCD cameras 3 and 4, and at this time, approximately half of the compact disc 1 which is vertically divided from the center is used as a field of view.

The range captured by the CCD camera 3 is preferably from image α to image γ, as shown in FIG. The image α is the outer peripheral edge of the diffusion plate 14, and the images β and γ
Is the outer peripheral edge of the small hole 14 a of the diffusion plate 14 (that is, the inner peripheral edge of the diffusion plate 14). That is, since the optical axis 3b of the CCD camera 3 is inclined by the angle θ with respect to the vertical line V, the CCD camera 3 does not reflect itself on the surface of the compact disc 1, but instead a part of the diffusion plate 14 is used for the compact disc. Reflected on one surface, the image is taken. Also,
The reflected image of the CCD camera 4 also fits exactly in the non-mirror surface portion 1a of the central portion of the compact disc 1 in the image projected by the CCD camera 3, so that the reflected image of the CCD camera 4 appears on the CCD camera 3 as a result. There is no. Also,
The non-mirror surface portion 1a on the inner side of the mirror surface portion 1b usually has no printed characters or the like and is not an object of the inspection, and therefore does not interfere with the inspection.

On the other hand, the range captured by the CCD camera 4 is
Since the image has a symmetrical relationship with the CCD camera 3 with the vertical line V as the center, the description thereof will be omitted here. However, as in the case described above, the reflected image of the CCD camera 4 itself is reflected in the captured image of the CCD camera 4. Also, the reflected image of the CCD camera 3 does not appear. The fields of view of the CCD cameras 3 and 4 partially overlap, and the surfaces of the compact discs 1 to be photographed are entirely within the focusing range of the lenses 3a and 4a. Thus each CCD camera 3, 4
The image taken in is sent to the image processing device 5 and compared with the image data which is inputted in advance and serves as a master to inspect the printing state on the surface of the compact disc 1.

As described above, in the image input apparatus for the optical inspection apparatus of the present embodiment, a plurality of CCD cameras are provided at the center of the image input apparatus only when the central portion of the mirror-like inspection object is not a mirror surface. It is possible to dispose them, and as a result, the entire image input device for an optical inspection device can be downsized. That is,
Although the circular fluorescent lamp 11 and the CCD cameras 3 and 4 are arranged above the compact disc 1 which is a mirror-like inspected object, the compact disc 1 is photographed from the small hole 14a in the substantially central portion of the diffusion plate 14. , The CCD cameras 3 and 4 themselves can be cleverly avoided from being reflected on the mirror surface portion 1b of the compact disc 1, and the surface condition of the compact disc 1 can be more accurately inspected by a smaller image input device. is there. In addition, in the present embodiment, the light source of the round fluorescent lamp 11 is uniformly diffused by the diffuser 14 so that the compact disc 1 as the target can be uniformly illuminated, so that the surface of the compact disc 1 is shaded. It is possible to reduce the occurrence of the occurrence, and it is easy to identify the printed characters and the like, and the inspection accuracy is improved.

Further, aluminum is vapor-deposited to form a mirror surface portion 1b.
When illuminating the compact disc 1 to be used, it is necessary to correctly select the light wavelength of the illumination light source, but the wavelength of the round fluorescent lamp 11 (JIS standard FCL-20N) is appropriate when inspecting printed characters and the like. Moreover, as the round fluorescent lamp 11, a commercially available one can be used as it is.
Is also easy to remove, so it is also excellent in maintenance.

The present invention can be variously modified without departing from the spirit of the invention. For example, the CCD cameras 3 and 4 can be modified.
Alternatively, another image pickup device (for example, a vidicon) may be used, and the diffusion plate 14 may be formed of glass instead of acrylic. The fluorescent lamp is not limited to the round shape, and a long fluorescent lamp can be used. Also, in the above embodiment, 2
The case where the CCD cameras 3 and 4 are used has been described, but the present invention is not limited to this, and four cameras may be used and the compact disc 1 may be divided into approximately four parts and photographed due to the demand for resolution. Furthermore, it goes without saying that the present invention can be applied not only to compact discs, but also to inspection of other mirror-like inspection objects having a hollow central portion.

[0019]

As described above, according to the image input device for an optical inspection apparatus of the present invention, it is not necessary to use a special part such as a half mirror, so that the components can be easily obtained and By reducing the number of constituent parts, the overall size and weight of the device can be reduced, and space can be saved, and it is resistant to vibration, and safer and more reliable inspections can be performed. Further, since the illumination efficiency of the specular object is good, the contrast of the image of the image pickup device is improved, and the surface inspection of the specular object can be stably performed, which is useful in automating the inspection device. Has the effect of being.

[Brief description of drawings]

FIG. 1 is an enlarged sectional schematic configuration diagram of an embodiment of an image input device for an optical inspection device of the present invention.

FIG. 2 is an enlarged cross-sectional view of the same mirror-like inspection object.

FIG. 3 is a partially cutaway perspective view of the same.

FIG. 4 is an exploded perspective view of the same.

FIG. 5 is a cross-sectional schematic configuration diagram of a conventional image input device for an optical inspection device.

[Explanation of symbols]

 1 Mirror-like inspected object 1a Non-mirror surface part 1b Mirror surface part 2 Inspection table 3, 4 Imaging device 6 Illumination device with diffuser plate

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[Procedure amendment]

[Submission date] December 28, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction content]

[0005]

Means for Solving the Problems An optical inspection apparatus for an image input apparatus of the present invention, for example如rather shown in FIG. 1, a plurality of image pickup apparatus for capturing a mirror surface-like object to be inspected, mirror-the previously described An image input device for an optical inspection device, comprising an illuminating device with a diffusion plate for illuminating an inspection object, wherein an image pickup device is attached such that its optical axis is tilted within a focusing range of a lens with respect to a mirror-like inspection object. ..

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image input device for an optical inspection device of the present invention will be described below with reference to FIGS. To schematic, optical inspection apparatus for an image input apparatus of this embodiment includes a plurality of imaging devices 3 and 4 for capturing a mirror surface-like object to be inspected 1, spreading to illuminate the mirror-inspected object 1 described above Backed Lighting device 6
And the optical axes 3b and 4b of the lenses 3a and 4a of the respective image pickup devices 3 and 4 are attached so as to be tilted in the focusing range with respect to the mirror-like inspection object 1. This configuration will be described in more detail below.

[Procedure correction 4]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

The diffusion plate 14 is formed of an acrylic resin material to have an outer diameter substantially the same as that of the light base 9 described above, and a minimum necessary amount corresponding to the lenses 3a and 4a of the CCD cameras 3 and 4 described above is formed in the central portion of the lower surface. The observation window 14a is provided to secure the light entrance path, and the outer diameter of the upper end is reduced to reduce the stepped portion 14b.
Is formed. The reduced step portion 14b is fitted into the protrusion of the light base 9 and screwed.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

The image captured by the CCD camera is shown in FIG. 2A.
The area surrounded by a square is inside. That is, it is approximately half of the CD including the chuck hole of the CD. In this way, overlapping observation of the central hole is necessary in order to obtain common position information with the other CCD camera. FIG. 2B shows the inspection area. The main part of the present invention is to dispose the image of the observation window 14a outside the inspection area. That is,
By inclining the camera unit by θ with respect to the vertical line V, the shadow of the observation window 14a, which is directly underneath, can be driven out of the inspection area as shown in FIG. 2C. Further, in order to minimize θ, the shadow of the observation window 14a is skillfully designed so that it fits exactly in the center of the CD. The field of view of the CCD camera 3a is represented by a range between an angle α and an angle γ, as shown by the hatched portion in B in FIGS.
The angle β and the angle β may be determined so as to be projected on the diffusion plate 14, respectively. That is, the outer diameter of the diffusion plate 14 is
The angle β determines the inner diameter of the observation window 14a. The optical axes of the two CCD cameras cross each other in order to minimize θ, and as shown in FIG. 2C, a reflection image of the observation window 14a is formed in the clamping area 1a which is a non-inspection area of the specular object. Deploy.

[Procedure Amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction content]

On the other hand, the range captured by the CCD camera 4 is
Since the image has a symmetrical relationship with the CCD camera 3 about the vertical line V, description thereof will be omitted here, but similar to the above case, the observation window 14a in the region to be inspected in the image captured by the camera 4 will be described. Arrange a reflection image of. The fields of view of the CCD cameras 3 and 4 partially overlap, and the surfaces of the compact disc 1 to be photographed are entirely within the focusing range of the lenses 3a and 4a. In this way, the images captured by the CCD cameras 3 and 4 are
The print state on the surface of the compact disc 1 is inspected by comparing with the image data which is sent to the image processing apparatus 5 and is input in advance as a master image data.

[Procedure Amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

As described above, in the image input apparatus for the optical inspection apparatus of the present embodiment, a plurality of CCD cameras are provided at the center of the image input apparatus only when the central portion of the mirror-like inspection object is not a mirror surface. It is possible to dispose them, and as a result, the entire image input device for an optical inspection device can be downsized. That is,
Although the circular fluorescent lamp 11 and the CCD cameras 3 and 4 are arranged above the compact disc 1 which is a mirror-like inspected object, the compact disc 1 is photographed through the observation window 14a in the substantially central portion of the diffusion plate 14. , The CCD cameras 3 and 4 themselves can be cleverly avoided from being reflected on the mirror surface portion 1b of the compact disc 1, and the surface condition of the compact disc 1 can be more accurately inspected by a smaller image input device. is there. In addition, in this embodiment, the light source of the round fluorescent lamp 11 is uniformly diffused by the diffuser 14 and the compact disc 1 as the target can be uniformly illuminated, so that the surface of the compact disc 1 is not shaded. It is possible to reduce the number of occurrences, it is easy to identify the printed characters and the like, and the inspection accuracy is improved.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

Further, aluminum is deposited to protect the surface from oxidation.
Compact disc 1 with a mirror surface portion 1b covered with a protective film
When illuminating, protect the interference fringes due to this protective film thickness.
It is necessary to select a light wavelength of fit illumination source correctly, the wavelength of the round fluorescent lamp 11 (JIS Standard FCL-20 N) is
It is suitable for inspecting printed characters and the like, and the round fluorescent lamp 11 can be a commercially available one as it is, and the diffusion plate 14 can be easily removed, which is also excellent in maintenance.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Name of item to be corrected] 0019

[Correction method] Change

[Correction content]

[0019]

As described above, according to the image input device for an optical inspection apparatus of the present invention, it is not necessary to use a special part such as a half mirror, so that the components can be easily obtained and By reducing the number of constituent parts, the overall size and weight of the device can be reduced, and space can be saved, and it is resistant to vibration, and safer and more reliable inspections can be performed. Further, since the illumination efficiency of the mirror-like object to be inspected is also good, and improved Contra <br/> be sampled image of the image pickup apparatus, it is possible to surface inspection of the specular object to be inspected can be stably performed, the inspection apparatus This has the effect of being beneficial in the automation of.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

FIG. 2 is a schematic linear plan view of an image captured by an imaging device.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

FIG. 3 is a partially cutaway perspective view of the image input device shown in FIG.

[Procedure Amendment 11]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure Amendment 12]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

Claims (1)

[Claims] 1. An image input for an optical inspection device, comprising: a plurality of image pickup devices for photographing a specular object to be inspected having a non-mirror surface portion in a central portion; and an illuminating device with a diffusing plate for illuminating the specular object to be inspected. The image input device for an optical inspection device, wherein the image pickup device is attached so that an optical axis of the image pickup device is inclined in a focusing range of a lens with respect to a mirror-like inspection object.