JP2000097870A - Inspection device for optical card intermediate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the occurrence of a pseudodefect as to an optical card intermediate, and also precisely carry out defect detection. SOLUTION: An image signal from the first region out of image signals of an optical card intermediate from a CCD line sensor camera 2 is differentiated in an X-differentiation processing filter 23a, and an image signal from the second region is differentiated in a y-differentiation processing filter 23b. Signals from the x- and y-differentiation filters 23a, 23b are input into respective binarization processing parts 24a, 24b. A defect of the optical card intermediate is detected thereafter by a CPU, based on signals binalization-processed therein.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical card intermediate product inspection apparatus for inspecting an optical card intermediate product having an optical recording layer formed on a duplicated transparent substrate.

[0002]

2. Description of the Related Art At present, with the spread of plastic cards such as cash cards and credit cards, a card society in which one person carries a plurality of cards has been formed. In general, magnetic cards based on magnetic recording have been the mainstream of conventional plastic cards, but IC cards such as electronic wallets are attracting attention due to advances in digital technology. The widespread use of cards has created a new demand for individuals to retain personal credit information and health histories, and there has been a demand for larger-capacity card-type recording media.

An optical card most expected as a large-capacity card can have a data capacity of several megabytes to several tens of megabytes per card. The optical card is in principle an optical disk in the form of a card, and a write-once WORM optical card is generally available rather than a read-only ROM optical card. The optical card is preformatted with prerecorded data for causing a reader / writer to recognize the contents of the optical card, and a track guide for causing a pickup to follow the data when reading and writing data. Such a preformat pattern is formed by minute concave or convex portions.
Depending on the type of the optical card, a barcode or a character indicating the type of format is also prerecorded on the optical card. Optical cards are standardized by ISO and JIS, and are expected to become popular in the future as the above demands increase.

[0004]

In such an optical card, a card original is pressed against a transparent substrate, or a 2P method is used.
It is obtained by copying a preformat pattern from a card original onto a transparent substrate by injection molding or the like, and laminating a backing substrate such as PVC to an optical card intermediate product having an optical recording layer formed thereon. In this case, it is necessary to inspect the optical card intermediate product, but the inspection of the optical card intermediate product has so far relied on human microscopic inspection.

The present invention has been made in view of the above points, and has as its object to provide an optical card intermediate product inspection apparatus capable of reliably and accurately inspecting an optical card intermediate product. .

[0006]

According to the present invention, there is provided an inspection apparatus for an optical card intermediate product having an optical recording layer including at least a first area and a second area. an xy table that moves in the y-direction, a projector that projects light onto the optical recording layer of the optical card intermediate product, a light receiver that receives light reflected from the optical recording layer of the optical card intermediate product, and a light receiver. An image processing device that performs image processing to detect a defect in an intermediate product of the optical card, the image processing device includes an x differential processing filter that differentiates an image signal from the first area in the x direction, and an image from the second area. A y-differential processing filter for differentiating the signal in the y-direction, a binarization processing unit for binarizing each of the signals from the x-differential processing filter and the y-differential processing filter, and detecting a defect based on the binarized signal CPU An inspection apparatus for an optical card an intermediate product, characterized by.

According to the present invention, the image signal from the first area having passed through the light receiver is differentiated in the x direction by the x differential processing filter, and the image signal from the second area is differentiated in the y direction by the y differential filter. . Next, a filter for x differentiation processing and y
A signal from the differential processing filter is binarized by a binarization processing unit, and a defect is processed by the CPU based on the signal from the binarization processing unit.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical card intermediate product inspection apparatus according to the present invention will be described below with reference to the drawings.

As shown in FIG. 1, an inspection device for an optical card intermediate product is an xy table 1 that moves in x and y directions.
0, and a tray 8 on which the optical card intermediate product 5 provided on the xy table 10 is placed. The tray 8 is provided with a suction hole (not shown) for sucking the optical card intermediate product 5, and the suction hole is connected to a vacuum pump 9. The tray 8 is provided with a guide 8a for holding the optical card intermediate product 5 at a fixed position. The edge 40 of the optical card intermediate product 5 is in contact with the guide 8a.

As shown in FIG. 1, a light projector 1 for projecting light onto the surface of an optical card intermediate product 5 is provided on a tray 8,
Light reflected from the surface of the optical card intermediate product 5 is received by the light receiver 4. The receiver 4 is C
A CD line sensor camera 2 and a condenser lens 3 provided on the optical card intermediate product 5 side of the CCD line sensor camera 2
And the CCD line sensor camera 2 has 50
One having 00 pixels (the number of effective pixels is 4000) is used.

Further, by arranging a plurality of close-up rings (not shown) between the CCD line sensor camera 2 and the condenser lens 3, the CCD can be adjusted without significant optical system adjustment.
The resolution by the line sensor camera 2 can also be changed. The width of one scan is determined in accordance with this resolution. In the present embodiment, the width of one scan is 20 mm in order to provide 5 μ resolution (the ability to detect a defect of 5 μ or more). Therefore, in the case of the optical card intermediate product 5 having an optical recording area having a width of 35 mm, it is necessary to perform two scans.

The CCD line sensor camera 2 is connected to an image processing device 6 for performing image processing to detect a defect of the optical card intermediate product 5, and the image processing device 6 is for controlling the drive of the xy table 10. Computer 7 is connected. The personal computer 7 further sets inspection conditions, executes inspections, statistically processes inspection results,
It also has a function of displaying a map of defect size and defect position information and calculating a yield for each lot.

Next, the image processing apparatus will be described with reference to FIG. The image processing device 6 includes an A / D converter 20 for A / D converting an image signal from the CCD line sensor camera 2, an image memory 21 for storing the image signal, and a median filter 22 for removing noise from the image signal. Have.
The median filter 22 includes an x differential processing filter 23a for differentiating the image signal from the mirror unit 14 in the x direction and a y differential processing filter for differentiating the image signal from the optical recording unit 13 in the y direction, as described later. 23b are connected in parallel, and the x-differential processing filter 23a and the y-differential processing filter 23b have a binarization processing unit 2 for binarizing the signal.
4a and 24b are respectively connected. Here, the x direction refers to the long side direction of the optical card, and the y direction refers to the short side direction of the optical card (see FIG. 2). Also, the binarization processing unit 24a,
A labeling unit 26 for displaying a defective portion on a raw image from the image memory 21 is connected to 24b.

Further, the above-mentioned A / D converter 20, image memory 21, median filter 22, x differential processing filter 23a, y differential processing filter 23b, binarization processing section 2
4a, 24b and the labeling unit 26
It is connected to PU25. The CPU 25 determines the result based on the signals from the binarization processing units 24a and 24b, and outputs the determination result to the image display unit 49.

Next, the optical card intermediate product 5 is shown in FIG.
This will be described with reference to (a), (b), (c), and (d). FIG. 2 (a)
(B) As shown in (c) and (d), the optical card intermediate product 5
Has a transparent substrate 50 and an optical recording layer 12 partially formed on the transparent substrate 50. An optical card pattern is pre-formatted on the transparent substrate 50, and the optical recording layer 12 includes a track guide 41 shown in FIG. 2B and an optical recording unit 13 containing preformat data 46 shown in FIG. 2C. And a mirror portion 14 disposed above and below the optical recording portion 13 and including a bar code 15 and characters 16 representing a format type. Here, FIG. 2D is a diagram showing a cross section of the optical card intermediate product 5.

As shown in FIG. 2A, the optical recording section 13 has acceleration regions 13 located at both left and right ends or one side.
a, 13a, a recording area 13c located at a central portion, and ID pre-recording areas 13b, 13b located between the acceleration areas 13a, 13a and the recording area 13c. A guard track 13d is arranged between the guard track 13d.

Further, as shown in FIG.
c is a number of track guides 41 and track guides 4
The track guide 41 has a width of 2.5 μ and a pitch of the track guide 41 of 12 μ. Further, as shown in FIG. 2C, the guard track 13d includes a plurality of track guides 44.
And a track 46 between the track guides 44,
The track 46 is provided with preformat data 46 with a space 47 interposed therebetween.

When such an intermediate product 5 is placed on the tray 8 shown in FIG. 1, as shown in FIG. 2D, the intermediate product 5 is usually placed with the optical recording layer facing upward, but the transparent substrate 50 When the inspection is to be performed with emphasis on the side, the optical recording layer 12 may be placed on the lower side.

Next, the operation of the present embodiment having the above configuration will be described. First, when light is projected from the projector 1 to the optical recording layer of the optical card intermediate product 5 while the xy table 10 is driven in the x direction, the reflected light from the optical card intermediate product 5 passes through the light receiving lens 3 and passes through the CCD line sensor. Enter camera 2. Next, the image signal of each line of the CCD line sensor camera 2 is A / D converted by the A / D converter 20 of the image processing device 6 and stored in the image memory 21.
Next, the noise of the image signal in the image memory 21 is removed by the median filter 22.

For example, the track guide 4 of the recording area 13c
1 has a width of 2.5 .mu. And has a resolution of 5 .mu.
The track guide 41 having the width is not detected as a defect. However, in some cases, it is conceivable to mistakenly detect the 2.5 μ-width track guide 41 as a defect. Such a pseudo defect is removed as noise by a filter, preferably a median filter 22. As such a median filter 22, an 8 × 4 filter shown in FIG. 8 is preferable, and the coefficients are as shown in FIG.

Next, an image signal from at least an area (hereinafter, a mirror surface area 100) including at least the mirror surface part 14 and the guard track 13d in the optical recording layer 12 of the optical card intermediate product 5 is x.
Differentiation is performed in the x direction in the differentiation processing filter 23a, and a maximum point based on the differentiation processing is obtained. At the same time, the optical recording layer 1
2, an image signal from an area of the optical recording section 13 that does not include the guard track 13d (hereinafter, the optical recording section area 101) is differentiated in the y-direction by the y-differential processing filter 23b, and a maximum point based on the differential processing is obtained. Desired. That is, x differential processing filter 23a and y differential processing filter 2
The signal from 3b is processed in each of the binarization processing sections 24a and 24b, and the result is sent to the CPU 25 to perform defect detection.

The defect 3 detected by the CPU 25
3 is displayed on the raw image from the image memory 21 by the labeling unit 26, and the display result is output to the image display unit 49 (see FIG. 3).

During this time, the personal computer 7
Controls the driving of the xy table 10 and sets the inspection conditions for the CPU 25. The personal computer 7 statistically processes the detection result from the CPU 25, displays a map of defect size and defect position information, and calculates the yield of the lot.

According to the present embodiment, the optical recording layer 12 of the optical card intermediate product 5 has the mirror surface area 100 and the optical recording area 1.
The image signal from the mirror surface area 100 is differentiated in the x direction, and the image signal from the optical recording unit 13 is differentiated in the y direction. As a result, the entire surface of the optical card intermediate product 5 is inspected without causing a pseudo defect except for the boundary portion 24 of the mirror surface portion 14 shown by a thick line as shown in FIG.
Can be detected. The pre-record data portion of the guard track 13d shown in FIG.
Because of the pitch, it is conceivable that the defect is detected as a pseudo defect while being unstable, but the mirror surface region 100 including the mirror surface portion 14 and the guard track 13d and the guard track 13
By setting different thresholds for the optical recording section 13 except for the point d, that is, for the optical recording section area 101, it is possible to prevent a pseudo defect from the guard track 13d. Specifically, by setting the threshold value on the mirror surface area 100 side to 200% (half the sensitivity) of the threshold value of the optical recording area 101, the entire surface can be inspected without generating a pseudo defect. .

There are other bar codes 15 and format types 16 that are preformatted on the mirror surface portion 14. These are also detected as pseudo defects. The position is specified and masked and excluded from the data.

The ID pre-record data section 13b,
13b is an area slightly lower than the recording area 13c when imaged because it has a resolution of 5 μ or less.

Next, as a comparative example, a case will be described in which either one of the x-direction differentiation and the y-direction differentiation is performed on the reflected light from the optical recording layer of the optical card intermediate product 5 without distinguishing the regions. When only differentiation in the x direction is performed, the optical recording unit 13 of the optical recording layer 12 is
Due to the presence of 3b and 13b, a pseudo defect 30 as shown in FIG. 4A is generated on both sides of the ID prerecord areas 13b and 13b due to differentiation in the x direction. When only the differentiation in the y direction is performed, the difference between the apparent reflectances of the mirror portion 14 and the optical recording portion 13 depending on the presence or absence of the preformat is given by
A pseudo defect 31 as shown in FIG. 4B is generated in the optical recording layer 12 by differentiation in the y direction. Therefore, if the AND of the differentials in the x direction and the y direction is calculated, the display unit 12 as shown in FIG.
, The number of pseudo defects 32 generated is greatly reduced.

However, as shown in FIG. 6, the true defect 33 is a combination of the four corners composed of the area 34 differentiated in the x direction and the area 35 differentiated in the y direction as shown in FIG.
Only the defect detection becomes unstable.

On the other hand, according to the present invention, the image signal from the mirror surface area 100 is differentiated in the x direction, and the image signal from the optical recording area 101 is differentiated in the y direction. The defect can be suppressed and the defect can be detected with high accuracy.

Next, the binarized defects detected by the binarization processing sections 24a and 24b are labeled by a labeling unit 26 on the raw image. At this time, the determination process is performed in the CPU 25 according to the standard of the cluster defect set by the personal computer 7.

Here, the dense defect is a defect 3 of about 10 μm.
3 are concentrated in a region of, for example, 3600 μm ² ,
These defects are individually small but have an adverse effect on the R / W of the optical card as a whole. In this case, if this minute defect 33 exceeds a count number within a set range, it is determined to be a defect. A nearby defect is a process that regards a defect that is mainly divided into two or more in image processing as a single defect if it is within a set parameter, and affects the defect size and the number of defects. give. In addition, the total area of the defects can be set. If the total area exceeds this, even if each defect is small, it is still determined to be defective. These results are finally sent from the CPU 25 to the personal computer 7 as information on the defect position and the size by the GPIB (general purpuse).
interface bus) for statistical processing and mapping.

As described above, if a high-resolution optical system is used to detect the defect size as close as possible to the actual defect size, there is an optical card intermediate product 5 that cannot inspect the entire surface in one scan due to the limitations of the light receiver 4. Therefore, the xy table 10 is reciprocated, but an overlapped portion is provided between two scans so as not to generate an uninspected portion, and the CPU 25 processes the data of the overlapped portion so that the result is appropriate.

In the conventional optical card inspection apparatus, in order to determine an inspection area, it is necessary to scan a card in advance and manually specify an area by using a cursor. This took more than twice the time required for the inspection and was uneconomical. In order to automate this, in the present invention, the right and left edges of the optical recording section 13 of the optical card intermediate product 5 shown in FIG. 2 are detected. Specifically, the xy table 10
Is moved to scan the optical card intermediate product 5. At this time, when the optical recording unit 13 enters the field of view of the light receiver 4, the reflectance increases. The CPU 25 sequentially compares the integrated values of the luminance of one line of pixels of the CCD line sensor camera 2 in the scanning direction, and calculates and generates a least square line based on the position data of the pixels at the position where the integrated value changes abruptly. This is the edge (boundary) of the optical recording unit 13.

[0034]

As described above, according to the present invention, the image signal from the first area of the optical card intermediate product is differentiated in the x direction, and the image signal from the second area is differentiated in the y direction. Therefore, the occurrence of a pseudo defect can be suppressed as compared with the case where the x-direction differentiation and the y-direction differentiation are performed on the entire region, and at the same time, the defect detection can be performed with high accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment of an optical card intermediate product inspection device according to the present invention.

FIG. 2 is a diagram showing an optical card intermediate product.

FIG. 3 is a diagram illustrating functions of the image processing apparatus.

FIG. 4 is a view showing a pseudo defect according to a comparative example.

FIG. 5 is a view showing a pseudo defect according to a comparative example.

FIG. 6 is a diagram illustrating a defect detection state according to a comparative example.

FIG. 7 is a diagram showing a defect detection state according to the present invention.

FIG. 8 is a diagram showing a median filter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Projector 2 CCD line sensor camera 3 Condenser lens 4 Receiver 5 Optical card intermediate product 6 Image processing device 7 Personal computer 8 Tray 10 XY table 11 Optical card intermediate product substrate 13 Optical recording area 14 Mirror surface part 22 Median filter 23a x differential Processing filter 23by y differential processing filter 24a, 25b Binarization processing unit 25 CPU

Continued on the front page F-term (reference) 2F065 AA49 BB02 BB22 CC00 DD06 FF01 FF04 HH12 JJ02 JJ08 JJ25 MM03 PP12 QQ03 QQ04 QQ06 QQ13 QQ18 QQ24 QQ25 QQ31 QQ34 QQ37 QQ41 SS13 2G051 AA07 EA01 EA03 EA03

Claims (3)

[Claims] 1. An optical card intermediate product inspection apparatus having an optical recording layer including at least a first area and a second area, comprising: an xy table on which an optical card intermediate product is placed and moved in x and y directions. A light emitter that projects light onto the optical recording layer of the optical card intermediate product; a light receiver that receives light reflected from the optical recording layer of the optical card intermediate product; An image processing device for detecting a defect of an intermediate product is provided. The image processing device includes an x differential processing filter that differentiates an image signal from the first area in the x direction and a y that differentiates an image signal from the second area in the y direction. A differential processing filter, a binarization processing unit that binarizes signals from the x differential processing filter and the y differential processing filter, and a CPU that detects a defect based on the binarized signal. To be Inspection apparatus of the card an intermediate product. 2. The optical card intermediate product inspection apparatus according to claim 1, wherein a filter for removing predetermined noise from the image signal is provided at a stage preceding the x differential filter and the y differential processing filter. 3. The optical card intermediate product according to claim 1, wherein the CPU of the image processing apparatus designates a predetermined area of the optical card intermediate product in advance and masks a signal from the determined area. Inspection equipment.