JP3197814B2 - Printing surface inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In general, a CD is formed by depositing an aluminum film 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 of the data surface of the CD, a maker name, a song name, a player name, and the like are printed. As an inspection device for inspecting whether or not the printing state is incomplete,
For example, as disclosed in Japanese Unexamined Patent Publication No. Hei. 4-14339, "illumination device for optical inspection apparatus", light emitted from a fluorescent lamp is irregularly reflected by a diffuse reflector, and the irregular light is reflected by a half mirror. The printed surface is inspected for defects by irradiating the printed surface, photographing the reflected light from the printed surface with an imaging device, and analyzing the image with an image processing device.

[0003]

In order to inspect a defect on a printing surface (hereinafter referred to as a label surface) of a mirror-like inspected object having a printing surface such as a CD, the label surface is not a character printed on the mirror surface. High reflectivity, almost mirror-like, with only a portion of the mirror surface printed with characters due to patterns, designs, etc. (hereinafter referred to as state 1) to low reflectivity, with the entire mirror surface covered with a design, etc. Until (hereinafter referred to as state 2), there are various mirror states (states with different reflectivities). If this label surface is illuminated by an illumination device, the reflected light is photographed by an image pickup device, and if image processing is to be performed to determine a defect on the label surface, if state 1 is illuminated with brightness suitable for state 2 In addition, the reflected light from the mirror surface is too strong, and the image captured by the imaging device is white and causes halation, and the defect on the label surface is erased by the halation. Also, conversely,
If the state 2 is illuminated with the brightness suitable for the state 1, the reflected light from the label surface is too weak, the image taken by the imaging device is too dark, and it is not possible to determine the defect on the label surface. As described above, it is difficult to irradiate the state 1 and the state 2 with the same brightness. For this purpose, it is necessary to change the brightness of the light source according to the mirror surface state of the label surface (a state in which the reflectance is different) and irradiate the label surface with a brightness suitable for defect determination.

[0004] In addition, a previously filed application is disclosed in Japanese Patent Application No. 8-577.
03 ", a fluorescent lamp and a halogen lamp are selectively used depending on the type of label surface defect, a fluorescent lamp is used for a color spot defect, and the other (a, b, c, d, e, and e shown in FIG. 5).
In the f) defect, use of a halogen lamp is described. Therefore, a fluorescent lamp is less likely to cause halation on a mirror surface to determine color spots on a printed surface such as a pattern, but a halogen lamp is used to determine both a printed surface of characters and the like and a mirror surface. Unless the brightness is changed between the state 1 and the state 2, a normal determination cannot be made. However, in order to electrically change the brightness of the halogen lamp, a dimming function is required, and dimming requires a dimming time of about 2 seconds. Therefore, even if the speed of the inspection line is increased to increase the productivity, the tact time of the inspection line cannot be reduced to less than 2 seconds.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides an illuminating device for a printing surface inspection apparatus, wherein a plurality of light sources are provided, and the illuminating device according to the mirror surface state (reflectance) of the label surface. Then, the number of light sources that irradiate the label surface is changed, and the light that irradiates the label surface is dimmed.

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

[0007]

In order to solve the above-mentioned problems, a lighting device of a printing surface inspection device such as a CD is provided with a plurality of light sources, and a plurality of light sources are provided according to a ratio of a mirror surface to a label surface. , Change the number of light sources that illuminate the label surface perpendicularly,
The light emitted to the label surface is adjusted so that halation does not occur in the reflected light from the label surface.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A printing surface inspection apparatus according to the present invention uses a CD
Illuminating device that irradiates a printing surface (label surface) of a mirror-like inspection object having a printing surface such as an imaging device, an imaging device that captures light reflected from the label surface, and an image processing device that analyzes an image captured by the imaging device And

Further, the illuminating device is provided with a fluorescent lamp and a halogen lamp as a light source, and a fluorescent lamp is used for a color spot defect on a color printing surface, and other than the color spot (a, b, c, d, and
A halogen lamp is used for defects e and f). The fluorescent lamp is electrically turned ON / OFF, and the halogen light source cuts off the optical path from the two halogen lamps by opening / closing means disposed on the entire surface of the halogen lamp in accordance with the ratio of the mirror surface to the entire label surface. By changing the number of halogen light sources, the brightness of the reflected light is changed. In other words, when the ratio of the mirror surface to the label surface is high (state 1), one of the two halogen light sources is shut off by the opening / closing means to lower the brightness and reduce the brightness of the label surface. When the ratio occupied by the mirror surface is low (state 2), the brightness is increased by opening both of the two 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 illustrating a main configuration of a CD printing surface inspection apparatus according to an embodiment. FIG. 2 is a sectional view of the CD printing surface inspection apparatus taken along line xx in the embodiment. FIG. 3 is a view of the CD printed surface inspection apparatus taken along the line yy in the embodiment.

As shown in FIGS. 1, 2 and 3, a CD printing surface inspection apparatus 1 includes an imaging device 4 for photographing reflected light from a label surface 3 of a CD 2 and an illumination device 5 for irradiating the label surface 3. And a main body frame 6 for fixing each device. The imaging device 4 includes a color CCD camera 7.
(1), black and white CCD camera 8 (4) and each C
It is composed of an image processing device (not shown) that analyzes an image captured by a CD camera. Lighting device 5
Comprises 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 at the center of the inspection table 9 with the label surface 3 facing upward, centered on the optical axis L of the imaging device. Above the half mirror 12, a color CCD camera 7 and a monochrome CCD camera 8 as the imaging device 4 are fixed. The color CCD camera 7 is fixed to an upper portion of a camera mounting frame 14 by a camera mounting bracket 13. The black-and-white CCD camera 8 has a structure in which the optical axes d of the four cameras intersect at right angles below the camera mounting frame 14.
It is arranged so as to be located at an even position outside the intersection of the diagonal lines s of the book, and the intersection coincides with the optical axis L of the color CCD camera 7. After adjusting the position of the image in the X and Y directions, the upper part of the camera mounting frame 14 is adjusted by the image adjusting bracket 15 to the image pickup device mounting frame 1.
8, and a contact fitting 16 is attached to the lower portion of the camera attachment frame 14. The contact fitting 16 is brought into contact with the inner periphery 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
It is fixed to the inner wall of the body frame 6.

The inspection table 9 is covered with, for example, a black cloth so as not to reflect the light from the half mirror 12 and the ring-shaped fluorescent lamp 19 (hereinafter, referred to as a fluorescent lamp). The fluorescent lighting device 10 includes a fluorescent lamp 19, a fluorescent lighting frame 20, and a diffusion plate 21.
Is fixed to the lower part 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 is coincident with the optical axis L is fixed to a fluorescent lighting frame 20 in parallel with the CD surface. A diffusion plate 21 is fixed to the bottom of the fluorescent illumination frame 20 in parallel with the CD surface. The diffusion plate 21 is used for the half mirror 12.
A circular hole 22 sufficient to allow the reflected light from the surface to the label surface 3 to pass therethrough is formed with the center coincident with the optical axis L. The diffusion plate 21 diffuses light from the fluorescent lamp 19 and emits 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 illumination device 2
3, the halogen light guided by the fiber cable 25 from the halogen light sources 241 and 242 becomes a plane parallel light beam by the surface illumination device 23, and is diffused and fixed in parallel to the front surface of the surface illumination device. The plane-parallel rays are diffused by the plate 26, and uniform diffused rays are emitted toward the half mirror 12.

A half mirror 12 disposed between an optical path formed between a CD and a CCD camera is provided with a surface illumination device 2.
3 is reflected toward the label surface 3. Here, the half mirror 12 is fixed to the main body frame 6 at an angle θ = 45 ° with respect to 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 a stage subsequent to each CCD camera, and processes an image from the CCD camera to determine an image defect.

The halogen light sources 241 and 242 are composed of halogen lamps 271 and 272 for generating light and the condenser lens 2 for condensing light generated from the halogen lamps 271 and 272.
8, the halogen lamps 271, 272 and the condenser lens 28
And an opening / closing means 30 for interrupting light by blocking a light path connecting the halogen lamps 271, 272 and the condenser lens 28 with a shutter plate 29.

As shown in FIG. 4, the opening / closing means 30 comprises a rotary solenoid 31 and a substantially rectangular shutter plate 29 fixed to a drive shaft thereof. When the rotary solenoid 31 is electrically turned on, the shutter plate 29 fixed to the drive shaft of the rotary solenoid 31 rotates by a predetermined angle (in the direction of arrow e) along an arc locus positioned in a direction perpendicular to the optical path. , Halogen lamp 271,
The optical path connecting the condenser lens 272 and the condenser lens 28 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 (in the direction of arrow c), and the halogen lamps 271, 27
The optical path connecting the lens 2 and the condenser lens 28 is blocked, and the halogen light is stopped.

When the ratio of the mirror surface to the entire label surface is high, that is, when the printing surface is narrow (in the case of state 1), the halogen lighting device 11 uses the shutter plate 29 to select one of the halogen lamps 271 and 272. One of them is closed, and the label surface is irradiated with one halogen lamp. When the ratio of the mirror surface to the entire label surface is low, that is, when the printing surface is wide (in the case of state 2), the halogen lamp 27 is
1 and 272 are both opened, and the halogen lamp 271,
272 irradiates the label surface. Then, the halogen light applied to the label surface is reflected on 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), and the defect on the label surface is detected. Is detected.

The body frame 6 surrounds 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 black side walls. In the lighting device.

Next, the types of defects that occur on the label surface 3 include a color spot defect on the color printing surface, a pinhole (a) due to dust or air bubbles mixed in the ink, and a printing ink as shown in FIG. Blurring (b) and bleeding (c), scratching of printed characters and figures (d), foreign matter remaining inside the transparent film that protects the aluminum reflective film (e), and the aluminum reflective film Pock marks (f), which are traces of dust and the like adhering to the transparent protective film to be protected and peeled off, are mainly used. The above defects are classified into color spot defects and other defects (a, b, c, d, e, and f shown in FIG. 5) when classified from the illumination side used for the defect inspection.

In this embodiment, the fluorescent lamp 19 and the halogen lamp 27 are selectively used depending on the type of the label surface defect.
Depending on the state of the label surface (the ratio of the mirror surface to the entire label surface), the two halogen lamps 271 and 272 may be used.
By opening and closing the shutter plate 29 as appropriate, the dimming of the halogen light is performed. According to the timing chart shown in FIG. 6, when a color spot defect is detected (detected by the color CCD camera 7) (timing in FIG. 6), the halogen lamps 271 and 272 are shut off and only the fluorescent lamp 19 is turned on. (Light. Conversely, when other defects (a, b, c, d, e, and f shown in FIG. 5) are detected (detected by a monochrome CCD camera), the fluorescent lamp 19 is turned off and the halogen lamp 271, 272 is opened and closed as appropriate according to the state of the label surface. That is, in the case of the state 1 (timing in FIG. 6), the brightness of the halogen light is weakened by shutting off the halogen lamp 272 and irradiating the label surface 3 with one of the halogen lamps 271. In the case of state 2 (timing in FIG. 6), the halogen lamp 271,
By opening both 272, the brightness of the halogen light applied to the label surface 3 is increased.

Next, the operation of the present 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.
N, the two halogen lights emitted from the two halogen light sources 241 and 242 are both shielded by the shutter plate 29. Then, the ring-shaped light is emitted from the fluorescent lamp 19 toward the diffusion plate 21, and the diffusion plate 21 diffuses the ring-shaped light from the fluorescent lamp 19, and places a uniform diffused light on the inspection table 9. The light is radiated to the label surface 3 of the placed CD2. Then, the reflected light from the label surface 3 passes through the half mirror 12 and is photographed by the color CCD camera 7. The color processing is performed by an image processing device (not shown) located after the color CCD camera 7. A defect is determined.

In the case of a defect other than a color spot, the fluorescent lighting device 1
0 fluorescent lamp 19 is electrically turned off, and the two halogen light sources 241 and 242 are in the state 1 (timing in FIG.
, And the label surface 3 is irradiated only with the halogen lamp 271. In the case of state 2 (timing in FIG. 6), 2
The shutter plate 29 is opened for both units, and the halogen lamp 27 is opened.
The label surface 3 is illuminated by both 1 and 272. In each state, the light emitted from the halogen light sources 241 and 242 is guided to the surface illumination device 23 by the fiber cable 25, converted into plane parallel light by the surface illumination device 23, and converted into plane parallel light 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 the black and white CC
The image is photographed by the D camera 8, and the image is processed by an image processing device (not shown) located after the monochrome CCD camera 8.
Defects other than color spots are determined.

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

[0026]

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

The number of light sources is changed according to the ratio of the mirror surface to the entire label surface of the mirror-like inspected object, and the light irradiated on the print surface is dimmed, so that the defect on the print surface can be reliably determined. As a result, defects due to erroneous determination can be reduced, and the efficiency of the inspection line can be increased.

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

[Brief description of the drawings]

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

FIG. 2 is an xx sectional view of the imaging device.

FIG. 3 is a view taken along the line y-y of the fluorescent lighting device.

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

FIG. 5 is an explanatory diagram of types of defects other than color spots generated on a CD printing surface.

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

[Explanation of symbols]

 Reference Signs List 3 printing surface, label surface, mirror surface 2 CD, mirror-like inspection object 5 lighting 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)

(57) [Claims] An illumination device for irradiating the label surface of a mirror-like inspected object having a label surface printed on a mirror surface, such as a CD, and an imaging device for photographing reflected light from the label surface are provided. In the printed surface inspection apparatus, the illumination device includes a plurality of light sources, and changes the number of light sources that irradiate the printed surface perpendicularly according to a ratio of a mirror surface to the label surface. Printing surface inspection device. 2. The lighting device according to claim 1, wherein the lighting device includes a plurality of light sources, wherein an optical path from the light sources is interrupted by opening / closing means, and the number of light sources that irradiate the label surface perpendicularly is changed. The printed surface inspection device according to the above. 3. The lighting device includes a plurality of halogen light sources, and an optical path from the halogen light sources is interrupted by opening / closing means.
2. The printing surface inspection apparatus according to claim 1, wherein the number of halogen light sources irradiating the label surface perpendicularly is changed.