JPH09281047A - Printed-face inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a printed-face inspection apparatus which surely discriminates the defect of the printed face of a mirror-like object to be inspected, comprising the printed face such as a CD or the like, which eliminates an erroneous discrimination and which enhances the efficiency and the productivity of inspection. SOLUTION: An illumination device 5 of a printed-face inspection apparatus 1 is provided with a plurality of light sources 241, 242. According to the reflectance of the printed face 3 of a mirrorlike object 2 to be inspected, which comprises the printed face 3, the number of light sources which irradiate the printed face 3 is changed, and reflected light is adjusted so as to be suitable for the discrimination of the defect of the printed face 3. Alternatively, an illumination device 5 is provided with halogen light sources 241, 242, optical paths from halogen lamps 271, 273 are made intermittent by a switching means 30, and the brightness of halogen light radiated to the printed face 3 is changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection device for inspecting defects such as characters and figures printed on a mirror surface of a compact disc (hereinafter referred to as a CD).

[0002]

2. Description of the Related Art Generally, in CD, an aluminum film is vapor-deposited on a transparent polycarbonate and a protective film for preventing oxidation is coated on the aluminum film. On the surface of this protective film,
In order to display the recorded contents on the data side of the CD, the manufacturer name, song name, performer name, etc. are printed. As an inspection device to inspect whether there is a defect in this printing state,
For example, as in JP-A-4-143639, “Lighting device for optical inspection device”, a light beam emitted from a fluorescent lamp is diffusely reflected by a diffuse reflection plate, and the diffuse light is reflected by a half mirror, and the reflected light is reflected. A defect on the print surface is inspected by irradiating the print surface, capturing the reflected light from the print surface with an imaging device, and analyzing the image with an image processing device.

[0003]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention When an attempt is made to inspect a printing surface of a mirror-like inspection object having a printing surface such as a CD (hereinafter referred to as a label surface) for defects, the label surface is printed on a mirror surface. Depending on the design, the pattern, etc., only a part of the mirror surface is printed, and the reflectance is almost close to the mirror surface state (hereinafter referred to as "state 1") to the one with low reflectance in which the entire mirror surface is covered with the pattern etc. Up to (hereinafter, state 2), there are various mirror surface states (states having different reflectances). This label surface is illuminated by an illuminating device, the reflected light is photographed by an image pickup device, and if it is attempted to identify a defect on the label surface by image processing, if the state 1 is illuminated with a brightness suitable for the state 2. The reflected light from the mirror surface is too strong, and the image captured by the image pickup device has white halation, and the defects on the label surface are erased by the halation. On the contrary,
When the state 2 is illuminated with the brightness suitable for the state 1, the reflected light from the label surface is too weak and the image captured by the image pickup device is too dark, so that the defect on the label surface cannot be discriminated. As described above, it is difficult to irradiate the state 1 and the state 2 with the same brightness. Therefore, it is necessary to change the brightness of the light source according to the mirror surface state of the label surface (state in which the reflectance is different) to illuminate the label surface with the brightness suitable for the defect discrimination.

In addition, the previously filed Japanese Patent Application No. Hei 8-577.
No. 03 ”, a fluorescent lamp and a halogen lamp are used according to the type of defects on the label surface, a fluorescent lamp is used for color spot defects, and others (a, b, c, d, e, shown in FIG. 5) are used.
For the defect of f), it is described that a halogen lamp is used. Therefore, the fluorescent lamp distinguishes the color unevenness of the printing surface such as a design, so that halation on the mirror surface is unlikely to occur, but the halogen lamp distinguishes both the printing surface and the mirror surface of the character, Normal discrimination cannot be performed unless the brightness is changed between the state 1 and the state 2. However, the halogen lamp needs a dimming function to electrically change the brightness, and dimming requires a dimming time of about 2 seconds. Therefore, even if the speed of the inspection line is increased and the productivity is increased, the takt time of the inspection line cannot be set within 2 seconds.

[0005]

In order to solve the above-mentioned problems, the present invention provides an illuminating device of a printing surface inspection apparatus with a plurality of light sources, and adjusts the mirror surface state (reflectance) of the label surface. Then, the number of light sources that illuminate the label surface is changed to adjust the light that illuminates the label surface.

Further, each of the plurality of light sources is provided with an opening / closing means for connecting / disconnecting the optical path from the light source, and the number of light sources is changed by blocking the optical path by the opening / closing means so that the light for irradiating the label surface is irradiated. Dimming.

Further, the present invention is effective as a means for rapidly dimming a halogen light source or the like, which requires a long time for the electric dimming function.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The printing surface inspection apparatus of the present invention is a CD
An illumination device that irradiates a printing surface (label surface) of a mirror-like inspection object having a printing surface such as a label surface, an imaging device that captures reflected light from the label surface, and an image processing device that analyzes an image captured by the imaging device. It has and.

Further, the illuminating device is provided with a fluorescent lamp and a halogen lamp as a light source, and the fluorescent lamp is used for the color spot defect on the color printing surface, except for the color spot (a, b, c, d shown in FIG. 5). ，
A halogen lamp is used for the defects e and f). The fluorescent lamp is electrically turned on / off, and the halogen light source is opened and closed according to the reflectance of the printing surface by the opening / closing means arranged on the front surface of the halogen lamp to interrupt the light path from the two halogen lamps. The brightness of the reflected light is changed by changing the number of. That is, when the reflectance of the label surface is high (state 1), the brightness is lowered by blocking one of the two halogen light sources by the opening / closing means, and the reflectance of the label surface is low (state 2). In this case, increase the brightness by opening both halogen lamps.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the main configuration of the CD printing surface inspection apparatus in the embodiment. FIG. 2 is a sectional view taken along line xx of the CD printing surface inspection apparatus in the embodiment. FIG. 3 is a yy arrow view of the CD printing surface inspection apparatus in the embodiment.

As shown in FIGS. 1, 2 and 3, the CD print surface inspection apparatus 1 includes an image pickup device 4 for photographing reflected light from the label surface 3 of the CD 2 and an illuminating device 5 for irradiating the label surface 3. And a body frame 6 for fixing the respective devices. The image pickup device 4 is a color CCD camera 7
(1 unit), black-and-white CCD camera 8 (4 units) and each C
It is configured by an image processing device (not shown) that analyzes an image captured by a CD camera. Lighting device 5
Is composed of an inspection table 9 on which the CD 2 is placed, a fluorescent lighting device 10, a halogen lighting device 11, and a half mirror 12.

The CD 2 is placed substantially in the center of the inspection table 9 with the label surface 3 facing upward, centered on the optical axis L of the image pickup device. Above the half mirror 12, a color CCD camera 7 and a monochrome CCD camera 8 as the image pickup device 4 are fixed. The color CCD camera 7 is fixed to the upper part of the camera mounting frame 14 by the camera mounting bracket 13. In the black and white CCD camera 8, the optical axes d of the four cameras intersect at a right angle under the camera mounting frame 14.
The diagonal lines s of the book are arranged so as to be evenly located outside the intersection, and the intersection coincides with the optical axis L of the color CCD camera 7. After adjusting the position of the image in the XY directions, the upper part of the camera mounting frame 14 is adjusted by the image adjusting bracket 15 to attach the imaging device mounting frame 1.
8, the contact metal fitting 16 is attached to the lower part of the camera mounting frame 14, and the contact metal fitting 16 is brought into contact with the inner circumference of the contact frame 17 to prevent the optical axis of the CCD camera from swinging. are doing. The imaging device mounting frame 18 and the contact frame 17 are
It is fixed to the inner wall of the body frame 6.

The inspection table 9 is covered with, for example, a black cloth or the like so as not to reflect light from the half mirror 12 and the ring-shaped fluorescent lamp 19 (hereinafter referred to as fluorescent lamp). The fluorescent lighting device 10 is composed of a fluorescent lamp 19, a fluorescent lighting frame 20 and a diffusion plate 21.
Is fixed to the lower portion of the main body frame 6 between the CD 2 and the half mirror 12 in parallel with the CD surface. Inside the fluorescent lighting device 10, a fluorescent lamp 19 whose center coincides with the optical axis L is fixed to the fluorescent lighting frame 20 in parallel with the CD surface. A diffuser plate 21 is fixed to the bottom of the fluorescent illumination frame 20 in parallel with the CD surface. The diffusion plate 21 is the half mirror 12.
A circular hole 22 sufficient to allow the reflected light from the label to the label surface 3 to pass therethrough is provided with its center aligned with the optical axis L. The diffusing plate 21 diffuses the light from the fluorescent lamp 19 and radiates uniform diffused light to the label surface.

The halogen lighting device 11 includes a surface lighting device 23.
And two halogen light sources 241, 242 and the surface lighting device 2
The halogen light guided by the fiber cables 25 from the halogen light sources 241 and 242 is made into a plane parallel light beam by the surface lighting device 23 and is fixed in parallel to the front surface of the surface lighting device. The plate 26 diffuses the plane parallel rays and radiates a uniform diffused light toward the half mirror 12.

The half mirror 12 disposed between the optical path formed between the CD and the CCD camera is a surface illumination device 2.
Diffuse light from 3 is reflected toward the label surface 3. Here, the half mirror 12 is fixed to the body frame 6 at an angle θ = 45 ° with the optical path. The reflected light from the printing surface 3 that has passed through the half mirror 12 is read as an image by the color CCD camera 7 and the monochrome CCD camera 8. An image processing device (not shown) is provided at the rear stage of each CCD camera, processes an image from the CCD camera, and determines an image defect.

The halogen light sources 241, 242 are halogen lamps 271, 272 for generating light and a condenser lens 2 for condensing light emitted by the halogen lamps 271, 272.
8, halogen lamps 271, 272, and condenser lens 28
The shutter plate 29 interrupts the optical path between the halogen lamps 271 and 272 and the condenser lens 28 and is opened and closed by an opening / closing means 30.

As shown in FIG. 4, the opening / closing means 30 is composed of a rotary solenoid 31 and a substantially rectangular shutter plate 29 fixed to its drive shaft. When the rotary solenoid 31 is electrically turned on, the shutter plate 29 fixed to the drive shaft of the rotary solenoid 31 is rotated by a predetermined angle (in the direction of arrow e) in an arc locus located in a direction perpendicular to the optical path. , Halogen lamp 271,
The optical path connecting the condenser lens 28 and 272 is opened, and the halogen light sources 241 and 242 emit halogen light. When the rotary solenoid 31 is turned off, the shutter plate 29 returns to the original position (direction of arrow c), and the halogen lamps 271, 27
The light path connecting 2 and the condenser lens 28 is blocked, and the halogen light is stopped.

The halogen illuminator 11 has a shutter plate 29 when the label surface has a high reflectance (state 1).
As a result, either one of the halogen lamps 271 and 272 is closed, and one halogen lamp illuminates the label surface. If the label surface has a low reflectance (state 2), the shutter plate 29 causes the halogen lamp 27
Both 1, 272 are open, halogen lamp 271,
The label surface is illuminated with two pieces of 272. Then, the halogen light irradiated on the label surface is reflected by the label surface, the reflected light is photographed by the image pickup device 4, and the image is analyzed by an image processing device (not shown) to check for defects on the label surface. To detect.

The body frame 6 encloses the illumination space up to the color CCD camera 7, the monochrome CCD camera 8, the half mirror 12, and the surface illumination device 23 of the halogen illumination device 11 with a black side wall, and external light Keeps you out of the lighting system.

Next, the types of defects that occur on the label surface 3 include color spot defects on the color printing surface, pinholes (a) due to dust or air bubbles mixed in the ink, and printing ink as shown in FIG. Dirt (b) or blurring (c), scratches due to chipping of printed characters or figures (d), contamination of foreign matter with dust remaining inside the transparent film that protects the aluminum reflective film (e), aluminum reflective film The pock mark (f), which is a trace of dust or the like that has adhered to a transparent protective film for protection and is peeled off, is the main one. The above defects are classified into color spot defects and other defects (a, b, c, d, e, f shown in FIG. 5) when classified from the illumination side used for defect inspection.

In the present embodiment, the fluorescent lamp 19 and the halogen lamp 27 are selectively used depending on the type of defects on the label surface.
Depending on the state (reflectance) of the label surface, the halogen light is adjusted by opening and closing the two halogen lamps 271 and 272 at appropriate times. According to the timing chart shown in FIG. 6, a color spot defect is detected (color C
In the case of (detection by the CD camera 7) (timing in FIG. 6), the halogen lamps 271 and 272 are shut off, and only the fluorescent lamp 19 is turned on (lighted). On the contrary, when other defects (a, b, c, d, e, f shown in FIG. 5) are detected (detected by the black and white CCD camera), the fluorescent lamp 19 is turned off and the halogen lamp 271. 272
Depending on the state of the label surface, open and close as appropriate. That is, in the case of state 1 (timing in FIG. 6), the halogen lamp 272 is shut off and one of the halogen lamps 271 irradiates the label surface 3 to weaken the brightness of the halogen light. In the case of the state 2 (timing of FIG. 6), both the halogen lamps 271 and 272 are opened to increase the brightness of the halogen light with which the label surface 3 is irradiated.

Next, the operation of this embodiment having such a configuration will be described.

In the case of a color spot defect (timing in FIG. 6), the fluorescent lamp 19 of the fluorescent lighting device 10 is electrically turned on.
Then, the halogen light emitted from the two halogen light sources 241 and 242 is blocked by the shutter plate 29. Then, ring-shaped light is emitted from the fluorescent lamp 19 toward the diffuser plate 21, and the diffuser plate 21 diffuses the ring-shaped light from the fluorescent lamp 19 and places a uniform diffused light on the inspection table 9. It radiates to the label side 3 of the placed CD 2. The reflected light from the label surface 3 passes through the half mirror 12, is photographed by the color CCD camera 7, and is colored by an image processing device (not shown) located at the rear stage of the color CCD camera 7. Defects are identified.

In the case of defects other than color spots, the fluorescent lighting device 1
The fluorescent lamp 19 of 0 is electrically turned off, and when the two halogen light sources 241 and 242 are in the state 1 (timing of FIG. 6), the halogen lamp 272 is moved to the shutter plate 29.
The label surface 3 is illuminated only by the halogen lamp 271. In the case of state 2 (timing in FIG. 6), 2
The shutter plate 29 is opened together with the halogen lamp 27.
The label surface 3 is irradiated with both 1 and 272. In each state, the light emitted from the halogen light sources 241 and 242 is guided to the surface illuminating device 23 by the fiber cable 25, converted into the plane parallel light by the surface illuminating device 23, and the plane parallel light is converted by the diffusion plate 26. The diffused and uniform diffused light is emitted toward the half mirror 12. The half mirror 12 reflects the diffused light toward the label surface 3 of the CD 2 at an angle of θ = 45 °. Then, the reflected light from the label surface 3 passes through the half mirror 12 and is CC for black and white.
An image processing device (not shown), which is photographed by the D camera 8 and is located at the rear stage of the monochrome CCD camera 8,
Defects other than color spots are identified.

CD2 in which a defect is detected by the above inspection
Is fed back to the production line (not shown) and treated as a defective product.

[0026]

The present invention is embodied in the form described above and has the following effects.

By changing the number of light sources according to the reflectance of the printing surface of the mirror-like inspection object and adjusting the light irradiating the printing surface, the defect of the printing surface can be surely discriminated, and the false judgment can be made. It is possible to reduce defects caused by another and improve the efficiency of the inspection line.

Further, by using the opening / closing means for dimming the light sources and changing the number of light sources, the dimming time can be shortened, the takt time of the inspection line can be shortened, and the productivity can be improved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional configuration diagram showing a main configuration of an embodiment of a CD printing surface inspection apparatus of the present invention.

FIG. 2 is a sectional view of the imaging device taken along line xx.

FIG. 3 is a yy arrow view of the same fluorescent lighting device.

FIG. 4 is a perspective view of an essential part of opening / closing means for the halogen light source.

FIG. 5 is an explanatory diagram of types of defects other than color spots that occur on the printed surface of a CD.

FIG. 6 is a timing chart showing a fluorescent lamp lighting timing, a halogen lamp intermittent timing, and a photographing timing of the image pickup apparatus.

[Explanation of symbols]

 3 Printing Surface (Label Surface) 2 Mirror-like Inspected Object (CD) 5 Illumination Device 4 Imaging Device 1 Printing Surface Inspection Device 241 Light Source (Halogen Light Source) 242 Light Source (Halogen Light Source) 30 Opening / Closing Means 271 Halogen Light Source (Halogen Lamp) 272 Halogen light source (halogen lamp)

Claims (3)

[Claims] 1. A printing surface inspection apparatus comprising: an illuminating device that irradiates the printing surface of a mirror-like inspected object having a printing surface; and an imaging device that captures reflected light from the printing surface. Is a plurality of light sources, and changes the number of light sources that irradiate the printing surface according to the reflectance of the printing surface. 2. The illuminating device includes a plurality of light sources, and an optical path from the light source is interrupted by an opening / closing means to change the number of light sources irradiating the printing surface according to the reflectance of the printing surface. The printing surface inspection apparatus according to claim 1, wherein 3. The halogen light source includes a plurality of halogen light sources, and the light path from the halogen light source is interrupted by the opening / closing means according to the reflectance of the printing surface to irradiate the printing surface. 2. The number of the above is changed.
The printing surface inspection device described.