JP2001307173A - Card authenticity discriminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a card authenticity discriminating device capable of objectively and speedily discriminating the authenticity of the card having a hologram where images based on diffraction patterns are formed plurally. SOLUTION: This card authenticity discriminating device is provided with a projection system 22, which is provided at a card 1 and projecting measuring light Q1 to the hologram 2 where the plural pictures 8, 9 and 10 based on the diffraction patterns 4, 5 and 6 having different array forming direction of a diffraction grating, a detecting system 23 having plural line sensors 28a to 28c for respectively detecting reflected diffraction light, reflected and diffracted by each diffraction grating, and discriminating means 30a to 30c and 31a to 31c for discriminating whether the card 1 is genuine or not by analyzing photoelectric output based on each reflected diffraction light of the line sensors 28a to 28c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a device for determining the authenticity of a card having a hologram on which an image based on a diffraction pattern is formed.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
Hologram sticker 2 on a card 1 such as a credit card
Is known. On the hologram seal 2, an image 4 'based on the diffraction pattern 3 is formed. The hologram seal 2 is used to determine the authenticity of the card 1.

Some cards 1 have a plurality of images formed by changing the direction in which the diffraction gratings constituting the diffraction pattern 3 are formed in order to prevent forgery.

FIG. 2 shows, for example, three diffraction patterns 4, 5,.
6A and 6B show a rectangular hologram seal 2 on which three types of images are formed, and FIG. 3A shows a diffraction pattern 4 in which diffraction gratings are arranged and formed in a direction orthogonal to one side 2 a of the rectangular hologram seal 2. FIG. 3 shows an image 8 based on
FIG. 3B shows an image 9 based on the diffraction pattern 5 in which the diffraction gratings are arranged in a direction obliquely 45 degrees to the right with respect to the arrangement direction of the diffraction gratings in the diffraction pattern 4, and FIG. FIG. 2 shows an image 10 based on a diffraction pattern 6 in which diffraction gratings are arranged diagonally at 45 degrees to the left with respect to the arrangement direction of the gratings. The seal 2 is formed,
The appearance of the images 8, 9, and 10 changes depending on the state of the incident light beam on the hologram seal 2. In FIG. 3, the arrows indicate the directions in which the diffraction gratings are formed, and the direction in which each diffraction grating extends is orthogonal to the direction in which the diffraction gratings are arranged.

Conventionally, the authenticity of the card 1 has been determined by visually checking the image formed on the hologram seal 2.

[0006]

However, when the image formed on the hologram seal 2 is visually inspected to judge the authenticity of the card, the image changes depending on the direction of the incident light beam or the card is damaged. It is difficult
There is a demand for a card authentication device that can objectively determine the authenticity of a card. At this time, it is desirable to change the arrangement direction of the gratings constituting the diffraction pattern so that the authenticity of the card on which a plurality of images are formed can be objectively and quickly determined.

The present invention has been made in view of the above circumstances, and has as its object to objectively and quickly verify the authenticity of a card having a hologram in which a plurality of images based on a diffraction pattern are formed. An object of the present invention is to provide a card authenticity determination device capable of performing determination.

[0008]

According to a first aspect of the present invention, there is provided a card genuineness judging apparatus for a hologram provided on a card and having a plurality of images formed based on diffraction patterns having different diffraction grating arrangement directions. A projection system for projecting measurement light, a detection system having a plurality of line sensors for respectively detecting the reflected and diffracted light reflected and diffracted by the respective diffraction gratings, and Determining means for analyzing whether the card is genuine or fake by analyzing the photoelectric output based on the detected photoelectric output.

According to a second aspect of the present invention, there is provided a card authenticating apparatus, wherein the detection system has a Fourier transform lens interposed between the line sensor and the card.

[0010]

FIG. 4 is a perspective view showing a schematic structure of an example of a card authenticity judging device according to the present invention.

In FIG. 4, reference numeral 20 denotes a box of a card authenticity judging device. The box 20 is provided with an entrance 21 for the card 1. As shown in FIGS. 5A and 5B, a light projecting system 22 for projecting measurement light to a hologram 2 provided on the card 1 and forming an image based on a diffraction pattern is provided inside the box 20. And a detection system 23 for detecting the reflected and diffracted light reflected from the hologram 2 and a circuit block section to be described later.

The light projecting system 22 includes a laser light source unit 24. The laser light source section 24 is a semiconductor laser 24
a and a collimating lens 24b. The collimator lens 24b serves to convert the laser light emitted from the semiconductor laser 24a into parallel measurement light.

The detection system 23 includes one Fourier transform lens 2
7 and three line sensors 28a to 28c. The card 1 is drawn into the box 20 and set at the front focal position f of the Fourier transform lens 27. The line sensors 28a to 28c are set at the rear focal position f '(f = f') of the Fourier transform lens 26.

The circuit block includes a control block 29, analysis blocks 30a to 30c, and determination blocks 31a to 31c as shown in FIG. The control block unit 29 controls turning on / off of the laser light source unit 24.

An on / off switch S1 is connected to the control block 29. ON / OFF switch S1
Is operated, the semiconductor laser 24a is turned on.

When the semiconductor laser 24a is turned on, the incident angle θ of the parallel measurement light Q1 with respect to the hologram seal 2 is fixed as shown in FIG.
As shown in (b), the light enters the hologram seal 2 from an incident direction at an angle φ = 0 with respect to the direction in which the line sensor 28 extends.

On the hologram seal 2, images 8, 9, and 10 based on three diffraction patterns 4, 5, and 6 are formed. The parallel measurement light Q1 enters from a direction orthogonal to the direction in which each diffraction grating of the diffraction pattern 4 extends.

The diffraction phenomenon is caused by the incident light vector component incident perpendicularly to the direction in which the diffraction grating extends, of the parallel measurement light incident on the diffraction grating. Therefore, the parallel measurement light Q1 is directed in the incident direction φ = 0 degree. 7, the diffraction reflected light (first-order diffraction light) 32 based on the diffraction pattern 4 is applied to the line sensor 2 as shown in FIG.
8a.

On the other hand, the diffracted reflected light 33 based on the diffraction pattern 5 is the incident light vector component Q of the parallel measurement light Q1.
Since 1 ′ contributes to the diffraction and the reflection vector component of the parallel measurement light Q1 exists, it is formed on the line sensor 28c provided on one side from the line sensor 28a.

The diffracted reflected light 34 based on the diffraction pattern 6 is such that the incident light vector component Q1 ″ of the parallel measurement light Q1 contributes to the diffraction, and the reflection vector component of the parallel measurement light Q1 exists. Since the component has a direction opposite to the reflection vector component based on the diffraction pattern 5, the component is formed on a line sensor 28b provided at a position opposite to the line sensor 28c with respect to the line sensor 28a.

Attention is now focused on only the diffraction pattern 4, and it is assumed that the parallel measurement light Q1 is incident on the hologram seal 2, and that the pitches P1 of the diffraction gratings of the diffraction pattern 4 are ideally arranged at regular intervals. 8, a light amount distribution R1 of the reflected diffraction light 32 having a sharp peak and a narrow width W is detected on the line sensor 28a. When the pitch P1 of the diffraction grating is not constant but varies, as shown by a broken line in FIG.
On the line sensor 28a, a light amount distribution R2 of the reflected diffraction light 32 having a spread width W larger than the spread width W of the light amount distribution R1 is detected. The peak intensity Z of the reflected diffraction light 32
Is determined by the depth (phase depth) of the groove 41 of the diffraction grating formed in the hologram seal 2 as shown in FIG.

When a diffraction grating having a large pitch P2 different from the pitch P1 of the diffraction grating is formed on the hologram seal 2, the position of the peak intensity Z of the light quantity distribution R1 of the diffracted reflected light 32 is shown in FIG. As described above, the peak intensity Z of the light amount distribution R1 of the diffracted reflected light 32 based on the diffraction grating pitch P1 is assumed to be located at the origin O (the center of the optical axis of the detection system) and deviates from the origin O.

In the real card, since the pitch of the diffraction grating formed on the hologram seal 2 and the depth of the groove of the diffraction grating are strictly controlled, the peak intensity Z of the light amount distribution of the reflected diffracted light and the light amount distribution thereof Is considered to be within a predetermined range.

On the other hand, in the counterfeit card, the pitch of the diffraction grating is significantly different from the pitch of the diffraction grating of the real card, or the pitch is almost the same but the pitch varies widely, or the pitch of the diffraction grating is large. The depth of the groove 41 is greatly different from the depth of the groove of the diffraction grating of the real card. These appear as optical characteristics such as the peak intensity of the light intensity distribution of the reflected diffracted light, the position of the center of gravity of the light intensity distribution, and the spread of the light intensity distribution. By analyzing these optical characteristics, a genuine card or a forged card is analyzed. Can be determined.

Further, depending on the type of the card, as described in the section of the prior art, three images based on three diffraction patterns having different directions must be formed on the hologram seal 2; In the case of a counterfeit card in which only three images are formed, three diffracted reflected lights 32, 33, and 34 are not obtained, and only one diffracted reflected light is obtained, and the peak intensity Z of the diffracted reflected light is obtained. , It can be determined whether or not the card is a counterfeit card.

Accordingly, as shown in FIG. 6, the diffracted and reflected lights 32, 3 detected by the line sensors 28a to 28c.
The photoelectric output based on 3, 34 is analyzed by the analysis block units 30a to 303.
0c, and the analysis block units 30a to 30c calculate the peak intensity Z of the light quantity distribution of the diffracted reflected light 32, 33, 34, its center of gravity XG, and its spread width W (standard deviation) by a statistical method. , It can be determined whether the card is a genuine card or a counterfeit card.

Now, in FIG. 6, the line sensor 28a
, I,..., N from the left, and the photoelectric output of each pixel is Xi, the center of gravity XG of the light quantity distribution is obtained by the following equation (1). Further, the spread width W of the light amount distribution is obtained as a standard deviation by the following equation (2).

[0028]

(Equation 1)

That is, each of the analysis block units 30a to 30
c has a function of performing a calculation based on the above equations (1) and (2) and temporarily storing the calculation result, and a function of temporarily storing the peak intensity Z.

The analysis outputs of the analysis blocks 30a to 30c are input to the determination blocks 31a to 31c. The decision block units 31a to 31c include comparators 43a to 43c.
3c, 44a to 44c, 45a to 45c, allowable value setting units 46a to 46c, 47a to 47c, 48a to 48c, and a comprehensive judgment unit 49.

The allowable value setting units 46a to 46c set the allowable range of the peak intensity Z of the light quantity distribution, and
47c sets the allowable range of the center of gravity of the light amount distribution, and the allowable value setting units 48a to 48c set the allowable range of the spread width of the light amount distribution.

For each of the diffraction patterns 4, 5, and 6 that form the images 8, 9, and 10, the peak intensity Z and the center of gravity X of the light amount distribution are obtained.
Since G and spread width W are different, each allowable range is set for each line sensor.

Each of the peak intensity analysis outputs from the analysis blocks 30a to 30c is input to the comparators 43a to 43c.
The comparators 44a to 44c include the analysis block units 30a to 30
c, the output of each center-of-gravity position analysis is input to the comparators 45a to 45a.
An output of each spread width analysis is input to 45c from the analysis block unit 30c.

The comparators 43a to 43c compare whether or not there is a peak intensity analysis output in the allowable range of the peak intensity for the card authenticity set by the allowable value setting units 46a to 46c. Is the tolerance setting unit 47
a to 47c to determine whether or not there is a center-of-gravity position analysis output in the center-of-gravity position allowable range.
Reference numeral 45c compares whether or not there is a spread width analysis output in the spread width allowable range for card authenticity set by the allowable value setting units 48a to 48c.

The results of these comparisons are input to the overall judgment section 49, and the overall judgment section 49 judges whether the card is a genuine card or a counterfeit card based on these comparison results. The determination result is displayed on the display unit 50.

According to the embodiment of the present invention, whether the card is a genuine card or a counterfeit card can be determined by the method described below.

For example, a real card 1 has a hologram seal 2 on which images based on three types of diffraction patterns are formed.
Is provided, and three peaks of the diffracted light obtained by projecting the measurement light to the hologram seal 2 must be detected. However, the reflected diffracted light obtained by projecting the measurement light to the hologram seal 2 When only one peak intensity is obtained, the card can be reliably determined to be a fake.

Further, even if the counterfeit card is made somewhat elaborate, the peak intensity of the light intensity distribution of the diffracted reflected light for each line sensor obtained by projecting the measurement light onto the hologram seal 2 is obtained. By judging whether or not the position of the center of gravity and the spread width thereof are within the allowable range for authenticity judgment, the authenticity of the card can be accurately judged.

[0039]

The card authentication device according to the present invention is constructed as described above, so that the authenticity of a card having a hologram in which a plurality of images based on a diffraction pattern are formed can be objectively and quickly determined. It has the effect that it can be done.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a card having a hologram seal.

FIG. 2 is an explanatory diagram illustrating an example of a diffraction pattern formed on a hologram seal.

3A and 3B are explanatory diagrams for explaining the details of the diffraction pattern shown in FIG. 2; FIG. 3A shows a diffraction pattern in which an arrangement direction of a diffraction grating is formed in a direction orthogonal to one side of a hologram seal; (B) shows a diffraction pattern in which the arrangement direction of the diffraction grating is formed at an angle of 45 degrees to the right with respect to the arrangement direction of the diffraction pattern shown in (a), and (c) shows the arrangement of the diffraction pattern shown in (a). A diffraction pattern in which the arrangement direction of the diffraction grating is formed at an angle of 45 degrees to the left with respect to the direction is shown.

FIG. 4 is a perspective view showing a schematic configuration of a card authenticity determination device according to the present invention.

FIGS. 5A and 5B are explanatory views showing a schematic configuration of an optical system of a card authenticity determination device according to the present invention, wherein FIG. 5A is a front view and FIG.

FIG. 6 is a circuit block diagram of a card authenticity determination device according to the present invention.

FIG. 7 is an enlarged explanatory view for explaining reflected diffraction light formed by the parallel measurement light Q1 incident on the hologram seal shown in FIG. 2, wherein the parallel measurement light Q1 is a diffraction pattern 4;
3 shows reflected diffracted light when the light enters from a direction orthogonal to the direction in which the diffraction gratings constituting the diffraction grating extend.

FIG. 8 is an explanatory diagram of a light amount distribution based on reflected diffracted light when the parallel measurement light Q1 is incident from a direction orthogonal to a direction in which each diffraction grating constituting the diffraction pattern 4 extends.

FIG. 9 is an explanatory diagram showing the depth of the groove of the diffraction grating of the diffraction pattern shown in FIG. 2;

FIG. 10 is an explanatory diagram of a light amount distribution based on reflected diffraction light when the parallel measurement light Q1 is incident from a direction orthogonal to a direction in which each diffraction grating constituting the diffraction pattern 4 extends,
11 shows a light quantity distribution based on the reflected diffraction light of a diffraction grating having a pitch larger than the pitch of the diffraction grating of the diffraction pattern 4 shown in FIG.

[Explanation of symbols]

 Reference Signs List 1 Card 2 Hologram seal (hologram) 22 Projection system 23 Detection system 28a-28c Line sensor 30a-30c Analysis unit (judgment unit) 31a-31c Judgment block unit (judgment unit) Q1 Parallel measurement light (measurement light)

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[Procedure amendment]

[Submission date] May 25, 2000 (2005.2
5)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

According to a second aspect of the present invention, there is provided a card authenticating apparatus, wherein the detection system includes a Fourier transform lens interposed between the line sensor and the card .

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

The detection system 23 includes one Fourier transform lens 2
7 and a light receiving section 28, and the light receiving section 28 has three lines.
It consists of sensors 28a-28c . The card 1 is drawn into the box 20 and set at the front focal position f of the Fourier transform lens 27. Line sensors 28a-2
8c side focal position f '(f of the Fourier transform lens 27
= F ').

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

When the semiconductor laser 24a is turned on, the incident angle θ of the parallel measurement light Q1 with respect to the hologram seal 2 is fixed as shown in FIG.
As shown in (b), the light enters the hologram seal 2 from an incident direction at an angle φ = 0 with respect to the direction in which the line sensor 28a extends.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0025

[Correction method] Change

[Correction contents]

Further, depending on the type of the card, as described in the section of the prior art, three images based on three diffraction patterns having different directions must be formed on the hologram seal 2; in the case of counterfeit cards, such as only pieces of image is not formed, the three diffracted reflected light 32, 33 and 34 is not obtained, et al., i.e.,
Since only give only one diffracted reflected light, the number of peak intensity Z of the diffracted reflected light, will be able to determine whether counterfeit cards.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0027

[Correction method] Change

[Correction contents]

Now, in FIG. 8 , the line sensor 28a
, I,..., N from the left, and the photoelectric output of each pixel is Xi, the center of gravity XG of the light quantity distribution is obtained by the following equation (1). Further, the spread width W of the light quantity distribution is obtained as the standard deviation σ by the following equation (2).

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Claims (2)

[Claims] 1. A light projecting system for projecting measurement light to a hologram provided with a plurality of images based on diffraction patterns provided on a card and having different arrangement directions of diffraction gratings, and the respective diffraction gratings A detection system having a plurality of line sensors for respectively detecting the reflected and diffracted reflected light, and analyzing the photoelectric output based on the reflected and diffracted light of each of the line sensors to determine whether the card is genuine or fake And a determination means for determining whether or not the card is authentic. 2. The card authenticating apparatus according to claim 1, wherein the detection system has a Fourier transform lens interposed between the line sensor and the card.