JPH0869680A - Security information code and its reading method - Google Patents

Abstract

PURPOSE: To add a higher security to a medium by mixing at least two kinds of reference coloring materials whose respective density is modulated so as to measure their spectral reflectances and providing them on the medium as recording information. CONSTITUTION: First, more than two kinds of reference coloring materials are selected. In this case, it is preferred to select the coloring materials having spectral reflectances that are not being seen in ordinary inks. Then, the density of the reference materials including a transparent ink are modulated. Although the density can be continuously modulated, it is preferred to stepwise change the density to finer than 32 gradations so as to improve the recording precision. Then, information sections are provided on a body at plural locations. Moreover, the security and the amount of information are further increased by providing the information sections in terms of a bar code manner. That means, a security information code 1 is provided on a card body 2 by more than two kinds of reference coloring materials having respective density modulated and mixed and provided in a bar code manner as a recording information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes use of the fact that each color material has a unique spectral reflection spectrum, and a security information code for imparting security to media such as securities and cards, and a reading method thereof. It is about.

[0002]

2. Description of the Related Art Conventionally, writing of information on a medium such as a card has been performed mainly by using a magnetic recording material. However, the recording method using this magnetic recording material makes it easy to write and erase information. On the other hand, it has a problem that it is easily used because it is widely used.

Therefore, recently, in order to solve such a problem, in addition to the magnetic recording material, a recording material for the purpose of security is provided on a medium such as a card.
It has been considered as one means. Then, as a method of this kind, a hologram is partially provided or an IR
A method of providing a bar code such as a bar or a magnetic bar has been studied.

However, none of these can be said to be decisive means.

That is, although holograms cannot be easily manufactured, they have high security, but since they can be judged only with the naked eye, they are clearly counterfeit and genuine if some of them are old and damaged. It becomes impossible to distinguish from goods.

Further, since the IR bar and the magnetic bar cannot be judged by the naked eye, but can be judged only by a special device, it can be said that the security is higher. However, the IR bar has a pattern of only the difference in absorption in the infrared region, and reproduction can be performed by reading the absorption and the pattern. In addition, the magnetic bar can be reproduced by reading the difference in magnetic force and its pattern.

[0007]

As described above, the conventional methods have a problem that it is difficult to impart a higher security to the medium.

An object of the present invention is to provide a security information code capable of imparting higher security to a medium and a reading method thereof.

[0009]

In order to achieve the above object, first, in the invention according to claim 1, at least two or more kinds of basic coloring materials for measuring the spectral reflectance are respectively provided. The density is modulated and mixed, and recorded information is provided on the substrate.

Here, in particular, as each of the basic coloring materials, a single pigment or a dye is used alone, or a combination of a plurality of pigments or dyes is used. The ratio in is constant.

As the above-mentioned basic coloring materials, those having absorption not only in the visible region but also in the ultraviolet region and the infrared region are used.

On the other hand, in the invention according to claim 4, in the method for reading the information code for security according to the invention according to claim 1, the spectral reflectance of the information portion recorded on the substrate is measured, and the measured. From the spectral reflectance, the previously-measured spectral reflectance data of each basic coloring material is used to calculate the mixing ratio and amount of each basic coloring material included in the information portion.

[0013]

Therefore, in the security information code and the reading method thereof according to the present invention, since it is based on the analysis of the spectral reflection spectrum, not simply by measuring the color, even if it is disassembled by the technique of electronic plate making, In the electromechanical technique, the color is separated by a three-color filter. Therefore, if the spectral reflection spectra are slightly different, it cannot be forged by the electromechanical technique to detect the difference.

Further, since the reading spectrum filter can be arbitrarily selected, the same color cannot be reproduced unless the color materials themselves are the same.

Further, since a general manufacturing method such as gravure printing or thermal transfer can be used and the characteristic peculiar to the molecular structure of the coloring material is used, it cannot be easily forged.

Furthermore, since the colors have already been mixed, it is extremely difficult to carry out a chemical analysis.

As described above, it becomes possible to impart higher security to the medium.

[0018]

[Examples] In order to impart a higher level of security to a medium, it is difficult to make a judgment with the naked eye, and it is possible to make a judgment only with a special device, and a code is not added depending on the pattern, or in addition to that. It is necessary that the pattern material itself has code information.

The present invention is intended to provide a medium such as a card with higher security that cannot be achieved by the conventional medium such as a card, and the card by using color mixture coding in combination with a magnetic recording material. It is provided on a medium such as.

An embodiment of the present invention based on the above concept will be described below in detail with reference to the drawings.

The present invention relates to the colors represented by coloring materials such as pigments and dyes,
That is, the fact that the spectral reflection spectrum is determined by the molecular structure and is unique to each pigment or dye, and that the spectral reflection spectrum obtained by color mixing has additivity is used.

That is, the spectral reflection spectrum of the coloring material and the spectrum of ultraviolet, visible, and infrared regions are a collection of absorptions corresponding to the molecular structure of the coloring material, including the interaction between molecules,
Although the colors look the same to the naked eye, the spectra are different for different molecules. It's like a molecular fingerprint.

On the other hand, regarding the additivity of color mixture, Kubelka-Munk's equation and Duncan's equation represent it.

That is, the Kubelka-Munk equation shows that the reflectance R can be represented by the absorption coefficient K and the scattering coefficient S of the medium in the turbid medium, and is expressed by the following equation.

K / S = (1−R _∞ ) ² / 2R _∞ (1) The equation (1) is solved for R _∞ as follows.

R _∞ = 1 + K / S {(K / S) ² +2 (K / S)} ^1/2 (2) Further, Duncan's equation is expressed by the respective absorption coefficient K _i and scattering coefficient when mixed. S _i indicates that additivity holds, and is as follows.

(K / S) _mix = (K ₁ C ₁ + K ₂ C ₂ + ... + K _i C _i ) / (S ₁ C ₁ + S ₂ C ₂ + ... + S _i C _i ) ... (3) where C _{1 to} C _i represent the mixing ratio of each primary color material.

This equation is derived in some approximation to a function of K / S. That is, it is a method generally called a constant number method or a two constant method. Then, the constant number method is expressed by the following equation.

(K / S) _mix = A ₁ C ₁ + A ₂ C ₂ + ... + A _i C _i + (K / S) _S (4) where A _i is K / S per unit concentration , (K /
S) _S is the K / S of the substrate.

This means that K / S is calculated by measuring the reflectance of each raw material for each wavelength, and K / S for each wavelength after mixing is calculated.
It shows that S is calculated. Furthermore, this K / S
It shows that the reflectance is calculated from the value of.

That is, if the spectral reflectance of the raw materials and the respective blending amounts are known, the spectral reflectance after mixing will be obtained by a certain calculation.

On the contrary, if the spectral reflectance of the mixed colors is measured, the blending ratio and the amount thereof can be calculated using the data of the primary colors.

That is, the mixing ratio C _i of each primary color material is arbitrarily changed to obtain (K / S) _mix , the predicted reflectance is calculated by the above equation (2), and the measured spectrum of the mixed colors is calculated. C _i at the time when it coincides with the reflectance is the desired mixture ratio and amount. In this case, a differential method or the like can be applied as a method of changing C _i .

Next, a specific coding method will be described.

That is, as a method of providing the coloring material, for example, a gravure printing method, an offset printing method, a thermal transfer method, an ink jet method, a silk screen printing method, a relief printing method, an electrophotographic method, an intaglio printing, etc. can be applied. .
Here, for convenience of description, the gravure printing method will be described as an example.

First, two or more types of basic color materials are selected. In this case, it is preferable to use a coloring material having a spectral spectrum that cannot be found in general ink.

Next, each of the basic color materials, including the transparent ink, is density-modulated and mixed. In this case, the density can be continuously modulated, but in order to improve the reading accuracy, it is preferable to gradually change the density to about 32 gradations or less for each color.

That is, when two types of basic coloring materials are used, one information portion can represent 32 × 32 ways. However, in the case of gravure printing, the total amount of base material and the amount of transparent ink are constant, so the actual amount will be much smaller. Further, if the number of basic color materials is further increased, the number of combinations will be further increased, but in order to secure a certain degree of reading accuracy, it is preferable that the number is 7 or less.

Next, a plurality of information parts can be provided on the base body. Further, by providing the barcode, it is possible to further increase the amount of information to be included and improve the security.

FIG. 1 is a plan view showing a configuration example in which a security information code according to this embodiment is provided on a card which is a medium.

That is, as shown in FIG. 1, the security information code 1 records at least two kinds of basic coloring materials for measuring the spectral reflectance by modulating their respective concentrations and mixing them. The information is provided on the card base 2 in the form of a bar code.

Here, each basic color material contains only a single pigment or dye, or a combination of a plurality of pigments or dyes, and the ratio in each basic color material. Is constant. Also, as the color material,
It is possible to use a material that absorbs not only in the visible region but also in the ultraviolet region and infrared region.

On the other hand, there are three ways to match the same color.
Each mixing ratio is selected so that the stimulus values are equal, but this is not necessary in the present embodiment, and a numerical value using a spectral curve as a filter is used instead of the color matching function of each basic coloring material. It is preferable.

Next, a method of reading the security information code 1 of this embodiment will be described.

FIG. 2 is a schematic diagram showing a configuration example of a reading device for realizing the method for reading the security information code 1 of this embodiment.

As shown in FIG. 2, the spectrophotometer 3 can be used to read the security information code 1. That is, the spectrophotometer 3 is used to measure the spectral reflectance of the information portion (security information code 1) recorded on the card substrate 2. At this time, it is possible to include not only the visible light region but also the infrared region and the ultraviolet region.

Next, using the arithmetic unit 4, the spectrophotometer 3
Using the spectral reflectance data of each basic coloring material that has been measured in advance and stored in the storage device 5 from the spectral reflectance obtained by, the composition of each basic coloring material included in the information part is used. Calculate the amount. Then, the obtained compounding ratio corresponds to the code of the information part.

Next, a more specific example of this embodiment will be described.

That is, ATSK yellow, cyan, and magenta of the gravure ink manufactured by Toyo Ink Co. were respectively added to 50% of the stock solution with methanol / water (50/50).
It was diluted with to obtain a basic concentration, and printed on a PET card with a gravure proofing machine GP2 manufactured by Kurashiki Spinning Co., Ltd.

Next, the spectral reflectance was measured with a spectrophotometer manufactured by Murakami Color Research Laboratory. Then, K / S was calculated from the spectral reflectance obtained by this measurement, and K / S per unit concentration at each wavelength was obtained.

On the other hand, the basic concentrations of yellow and cyan were mixed and stirred in equal amounts, and the spectral reflectance was measured. Further, the K / S of the color mixture was calculated using the formula (4), and the spectral reflectance was measured using the formula (1). As a result, the calculated spectral reflection spectrum matched the spectral reflection spectrum generated by the measurement with an error of 4% or less.

Further, using the characteristic values obtained by using the absorption characteristics of each ink as a spectral filter, the compounding ratio of each color that is the closest to the measured value was calculated by the differential method.
The results were 50% cyan.

As described above, in this embodiment, at least two kinds of basic coloring materials for measuring the spectral reflectance are mixed by modulating their respective densities and recorded on the card base 2 as recording information. The card base 2 when the security information code 1 is read.
The spectral reflectance of the information portion (security information code 1) recorded above is measured by the spectrophotometer 3, and the measured spectral reflectance is measured in advance by the arithmetic device 4 and stored in the storage device 5. By using the data of the spectral reflectances of the respective basic coloring materials, the mixing ratio and the amount of the respective basic coloring materials included in the information part are calculated.

Therefore, it is difficult to forge based on the peculiarity of each basic coloring material, and there are many combinations of color mixture, difficulty of chemical analysis due to color mixture, and further possibility of combined use with bar code and magnetic recording. Therefore, it is possible to obtain a card or the like having a higher level of security that could not be realized by the conventional method.

That is, in the security information code and its reading method of the present embodiment, the color is not simply measured but the spectral reflection spectrum is analyzed. Therefore, even if it is disassembled by the electronic platemaking technique. In the electronic plate-making technique, the components are separated by the three-color filter, so if the spectral reflection spectra are slightly different, it cannot be forged by the electronic plate-making technique in order to detect the difference.

Further, since the reading spectrum filter can be arbitrarily selected, the same color cannot be reproduced unless the color materials themselves are the same.

Further, since general manufacturing methods such as gravure printing and thermal transfer can be used, and since the characteristics peculiar to the molecular structure of the coloring material are used, it cannot be easily forged.

Furthermore, since the colors have already been mixed, it is extremely difficult to carry out a chemical analysis.

As described above, it becomes possible to add a higher degree of security to the medium, and it is possible to provide an extremely effective countermeasure against counterfeit counterfeiting crimes that are expected to increase in the future. .

[0060]

As described above, according to the present invention, at least two or more kinds of basic color materials for measuring the spectral reflectance are mixed by modulating their respective densities, and recorded as record information on the substrate. When the security information code is read, the spectral reflectance of the information portion recorded on the substrate is measured, and the basic colors measured in advance are measured from the measured spectral reflectance. By using the spectral reflectance data of the material to calculate the mixing ratio and amount of each basic color material contained in the information area, it is possible to give a higher level of security to the medium. Information code and its reading method can be provided.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment in which a security information code according to the present invention is provided on a card which is a medium.

FIG. 2 is a schematic diagram showing a configuration example of a reading device for realizing the method for reading a security information code according to the same embodiment.

[Explanation of symbols]

1 ... Security information code, 2 ... Card base, 3
... spectrophotometer, 4 ... arithmetic unit, 5 ... storage unit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G06K 7/00 W 7623-5B 7/12 Z 7623-5B 19/06

Claims (4)

[Claims] 1. A security characterized in that at least two or more kinds of basic coloring materials for measuring spectral reflectance are mixed by modulating their respective densities and provided as record information on a substrate. Information code for. 2. As each of the basic coloring materials, a single pigment or dye is used alone, or a combination of a plurality of pigments or dyes is used. The ratio is set to be constant.
Information code for security described in. 3. The security information code according to claim 1, wherein each of the basic color materials is one that absorbs not only in a visible range but also in an ultraviolet range and an infrared range. 4. The method for reading a security information code according to claim 1, wherein the spectral reflectance of the information portion recorded on the base is measured, and the spectral reflectance is measured in advance from the measured spectral reflectance. The information code for security is characterized in that the compounding ratio and amount of each basic color material contained in the information part is calculated by using the data of the spectral reflectance of each basic color material. How to read.