JP4627767B2 - Information recording medium - Google Patents

Description

The present invention relates to an information recording medium capable of realizing high value-added products such as prepaid cards, cash vouchers, bonds, and program software packages by adding management information for preventing forgery.

  As the recording medium card, (1) a prepaid card or (2) a cash card is used. Examples of (1) include a telephone card issued by NTT (Nippon Telegraph and Telephone Corporation), a pachinko game card issued by the Nippon Card System, or a periodic / ticket / prepaid card issued by a transportation facility. Examples of (2) include bank cash cards and credit card companies. Whether or not these are genuine products is determined by reading or collating magnetic data stored in the card, or by determining whether the product is a genuine product by using a face photograph or hologram attached to the card. Furthermore, various management information on manufacture and use such as date of manufacture, frequency of use, and personal identification number is recorded as magnetic data in the card and rewritten. In addition, (3) gift certificates such as gift certificates and beer coupons, and (4) securities such as stocks and public bonds use advanced printing technology and holograms to prevent counterfeiting and write management information. Bar code etc. are used. Further, recently, (5) holograms and the like have been used in computer program software as a proof of authenticity.

  The above high-value-added products are easily altered or tampered with and become a big social problem. Of these, the cards ((1) to (2)) are filed on March 31, 1993 as a measure for preventing falsification and falsification, Japanese Patent Application No. 5-094846, “Recording Card and its Authenticity Determination Device” ( (Applicant: Iwasaki Tsushinki Co., Ltd.) has been proposed. In this prior art 1, the record carrier card comprises a conventional first magnetic recording area and a second recording area comprising an amorphous ferromagnetic layer, and a security code is recorded in this second recording area. In addition, it has a structure capable of magnetically detecting punch holes for displaying the frequency and the like. Therefore, it has an excellent advantage of easily detecting falsification by a shielding material that hides the punch hole, and the security code provided in the second recording area cannot be rewritten or erased. You can judge false.

  Also, Japanese Patent Application No. 8-276878 “Information Recording Medium” (Applicant: Iwasaki Tsushinki Co., Ltd.) filed on September 30, 1996, which combined an amorphous ferromagnetic thin film and a hologram as an information recording medium, was proposed. ing. By providing the hologram and the amorphous ferromagnetic material, the conventional technique 2 can magnetically read information recorded in the amorphous state in addition to the function originally possessed by the hologram.

Furthermore, as a method of easily adding signals to these magnetic materials, Japanese Patent Application No. 8-231288, filed on August 14, 1996, “Magnetic Patterned Magnetic Plate and its Manufacturing Method” (Applicant) : Iwasaki Tsushinki Co., Ltd.) has been proposed. In this prior art 3, unevenness is provided on a flat substrate by applying ink or by scientific / physical methods, the magnetic characteristics are changed between the flat area and the uneven area, and information recorded by the difference is recorded. It can be read magnetically.
Japanese Patent Application No. 5-094846 Japanese Patent Application No. 8-276878 Japanese Patent Application No. 8-231288

  On the other hand, for example, a micro-order unevenness (diffraction grating) is provided on the surface of a hologram, and a metal thin film is formed on the hologram to reproduce a characteristic pattern such as a three-dimensional image or an interference color to prevent forgery. The metal used at this time only needs to reflect light moderately, inexpensive aluminum or the like is used, and magnetic metal is not generally used. Producing such micron-order irregularities requires a very advanced technique and cannot be easily counterfeited, but in recent years there have been cases of forgery.

  As a technique for writing magnetic data, the above-described conventional technique 2 (Japanese Patent Application No. 8-276878, “Information Recording Medium”) uses magnetic materials of different materials or records information depending on the presence or absence of magnetic materials. Therefore, it is necessary to use an amorphous magnetic material and write a signal to the magnetic material separately from the hologram.

  The object of the present invention is to eliminate the disadvantage that high-value-added products such as conventional prepaid cards, cash cards and cash vouchers can be forged and altered relatively easily, and transfer them to various high-value-added products as well as cards. Another object is to provide an information recording medium having a forgery prevention function that can be easily added by pasting.

In order to achieve this object, an information recording medium according to the present invention includes a base material, and irregularities of a diffraction grating regularly or irregularly provided on the surface of the base material. And a ferromagnetic thin film formed of an amorphous ferromagnetic material on the hologram region, and the ferromagnetic material is used as management information for preventing counterfeiting. An information recording medium in which a thin film has characteristic magnetic characteristics corresponding to the hologram pattern or the shape pattern of the hologram area, and several hologram patterns are arranged in a plurality of directions in the hologram area. And is arranged so that anisotropy is eliminated by changing the direction of the diffraction grating in each divided region .

  As described above in detail, the information recording medium with high security can be obtained by combining the hologram region and the magnetic material according to the present invention, the signal can be read magnetically, the authenticity can be determined, and the visual inspection can be performed. The authenticity can be determined optically such as image recognition or machine reading. Furthermore, it is also possible to add a magnetic signal with a hologram as required.

The present invention comprises a hologram for optical authenticity determination and a magnetic film for magnetic signal reading and authenticity, and the magnetic film is formed directly on the diffraction grating of the hologram or with a nonmagnetic metal film interposed. Is formed. Since the magnetic material used in the present invention is basically a thin film formed by vapor phase growth such as vapor deposition or sputtering, the magnetic properties are greatly influenced by the surface state, particularly the surface irregularities. The ferromagnetic thin film is formed as a reflective layer in the same concave-convex shape along the concave-convex surface of the diffraction grating, and in some cases, light is applied between the substrate and the ferromagnetic thin film or next to the ferromagnetic thin film. A nonmagnetic metal film may be further formed as the reflective layer. In this case, the glossy color of the non-magnetic metal can be observed as reflected light from the outside without being affected by the color of the ferromagnetic thin film. No information recording medium is given. As the base material, a resin film is usually used. However, if a hologram pattern can be formed on the surface and can be added to various media by pasting, transferring, inserting, etc., such as metal, glass, etc. Other materials can be used. In addition, as a material of the ferromagnetic thin film used in the present invention, a soft magnetic material and a hard magnetic material can be used, and not only a crystalline ferromagnetic material but also an amorphous (non-crystalline) ferromagnetic material should be used. Can do. Furthermore, when the information recording medium of the present invention is pasted and transferred to various target objects, if a transparent resin film, glass, or the like is used for the substrate, the ferromagnetic thin film side is turned down and the substrate side is turned up. Can be used as a hologram protective layer. Further, when affixing / transferring on various objects with the ferromagnetic thin film facing up, it is preferable to further provide a transparent resin protective layer on the ferromagnetic layer. In general, when scratches are scratched in one direction on a flat substrate or processed into a fine rectangle by patterning, shape magnetic anisotropy occurs, and there is an easy magnetization axis along the scratches or pattern. It is known that. In the above-mentioned Prior Art 3 “Magnetic Patterned Magnetic Plate and Method for Producing the Same” (Japanese Patent Application No. 8-231288), a flat substrate is provided with unevenness by applying ink or by chemical / physical methods. The magnetic characteristics are changed between the uneven area and the uneven area, and the recorded information is read magnetically due to the difference. On the other hand, in the present invention, for example, it is formed so as to be observed as a hologram pattern by reflected light from a diffraction grating in which irregularities of the order of microns (μm) are regularly or irregularly provided on the surface of a substrate such as a resin. A hologram film is included, and a ferromagnetic thin film is formed on the hologram area, whereby the magnetic film retains the characteristic magnetic characteristics corresponding to the hologram pattern or the shape pattern of the hologram area. The change in magnetic characteristics is specifically a change in coercive force, saturation magnetic flux density, squareness ratio, and the like. The magnetic characteristics of the information recording medium according to the present invention are characterized by a combination of the magnetic characteristics of the original magnetic material and the shape effect of the hologram pattern.

  In the first form, there is a hologram region composed of a diffraction grating having a resin film as a base material and regularly provided with irregularities on the surface thereof, and the entire diffraction region of the hologram region is arranged according to a predetermined rule. A ferromagnetic thin film is directly formed on the diffraction grating. This is cut into a predetermined shape, and forged or attached to a high value-added product made of paper or plastic, it is possible to prevent forgery of the high value-added product. When embedding in a high value-added product such as an insertion, embed the information recording medium near the surface so that it can be magnetically read, or at least part of the magnetic hologram information recording medium if you want to optically check the hologram Must be exposed on the surface. Also, if the base material on which the hologram is to be formed is thinned and pasted on a thicker base material in advance, and an adhesive layer is provided after the magnetic material is deposited, the hologram can be pasted in an arbitrary shape by transfer Can do.

  In the first embodiment, the hologram area is formed on the entire surface or a part of the information recording medium. For example, when a hologram pattern is formed on the entire surface or a part of an information recording medium, when the hologram diffraction grating and the magnetic flux for reading excitation are arranged in parallel so as to be parallel to each other, the ferromagnetic material is directly formed on the hologram pattern. When the film is formed, the easy magnetization axis is strongly oriented in the entire hologram region, and magnetic characteristics different from those obtained when a ferromagnetic material is formed on a flat surface such as a PET (polyester) film or a mirrored nonmagnetic metal plate are exhibited. In addition, when the hologram area is divided into several parts, the orientation of the diffraction grating is changed in each of the divided areas so as to eliminate anisotropy, and a ferromagnetic material is formed thereon, the in-plane magnetic anisotropy Thus, an information recording medium showing the same magnetic characteristics can be obtained regardless of the direction of reading. This information recording medium can read a signal magnetically and determine authenticity from its magnetic characteristics, and can also make an authenticity determination optically by visually confirming the hologram.

  Next, in the second form, there is a zone where there is a hologram region in which a resin film is used as a base material and irregularities of the diffraction grating are regularly provided on the surface, and a zone where there is no hologram region. The diffraction gratings are arranged on the entire surface in accordance with one fixed rule, and a ferromagnetic thin film is directly formed on the surfaces of both the existence area where these hologram areas exist and the absence area where these hologram areas do not exist. In this way, two types of magnetic characteristics corresponding to the presence or absence of the hologram area 0 can be held in the information recording medium, and data can be written using the difference in the magnetic characteristics. As in the case of the first form, it can be added to a high value-added product by pasting, inserting and transferring.

In the second form, the presence area and the absence area corresponding to the presence or absence of the hologram area on the information recording medium are provided according to a predetermined rule. The magnetic signal is changed depending on the presence or absence of the hologram area, and this is used as data. For example, when a hologram region is arranged using a ferromagnetic material so that the direction of the magnetic flux for reading and excitation of the hologram is parallel, the easy magnetization axis is strongly oriented in the hologram region, and the magnetic characteristics are exhibited by the presence or absence of the hologram region. Change, read this, and give a signal. This information recording medium can read a signal magnetically, determine authenticity from its magnetic characteristics, and can optically determine authenticity by visually confirming the hologram pattern. Will be able to record various management information such as date of manufacture or personal identification number as magnetic data on high value-added products.

  Further, in the third embodiment, at least two types of hologram regions having different patterns exist by changing the angle of the diffraction grating, for example, and a soft magnetic thin film is directly formed thereon. In this way, two or more types of magnetic characteristics corresponding to the hologram pattern can be held in the information recording medium, and data can be written using this difference in magnetic characteristics. As in the case of the first form, it can be added to a high value-added product by pasting, inserting and transferring.

  In the third embodiment, two or more types of different hologram patterns are present, and the magnetic characteristics change due to different hologram patterns. This can be used as data. The holograms having different patterns here are diffraction gratings having different diffraction grating stripe angles (directions) and line-gap dimensions. Changing the pattern changes the magnetic properties. For example, when a hologram is arranged alternately while rotating the diffraction grating of the hologram by 90 ° using a ferromagnetic material, the diffraction grating is rotated by 90 ° in the region where the direction of the magnetic flux for reading and excitation is parallel. Compared to the region, the easy axis of magnetization is strongly oriented, and the magnetic characteristics change depending on the hologram pattern, which can be read out separately and given a signal. This information recording medium can read a signal magnetically, determine authenticity from its magnetic characteristics, and can optically determine authenticity by visually confirming the hologram pattern. Will be able to record various management information such as date of manufacture or personal identification number as magnetic data on high value-added products.

  In the fourth embodiment, image information such as a portrait, a three-dimensional image, and characters is written in the hologram area, and a ferromagnetic thin film is directly formed thereon. By doing so, a change in magnetic characteristics corresponding to image information written in the form of a pattern in the hologram area is recorded on the information recording medium. As in the case of the first form, it can be added to a high value-added product by pasting, inserting and transferring.

In the fourth embodiment, image information such as a portrait, a three-dimensional image, and characters is provided in a part of a uniform hologram area. In this case, the magnetic characteristics change depending on the presence / absence of image information, and the magnetic characteristics change continuously or discontinuously within the region where the image is provided, depending on the shape of the image and the way the image information is formed. By doing so, a change in magnetic characteristics corresponding to the image information written on the hologram is recorded on the magnetic hologram information recording medium. For example, consider a case where another diffraction grating pattern is provided with a round pattern in a uniform hologram region and a ferromagnetic material is used. In a certain hologram area, the direction of the diffraction grating and the magnetic flux for reading excitation is set to 45 °. The round pattern provided in the hologram area is such that the direction of the magnetic flux for reading and excitation is parallel to the hologram diffraction grating. When this is read from one end to the other end with a magnetic head, the magnetic characteristics are different between the uniform area where the diffraction grating is 45 ° and the circular pattern where the diffraction grating is parallel, and the magnetic characteristics unique to the round pattern change. Can be detected. In this way, it is possible to read the change in magnetic characteristics according to the design, and to give a unique magnetic property change to an information recording medium having a design. This information recording medium can read a signal magnetically, determine authenticity from its magnetic characteristics, and can optically determine authenticity by visually confirming the hologram pattern. Reads a change in magnetic characteristics in accordance with image information written in the hologram area, and refers to a change in the magnetic characteristics of the genuine product, thereby making it possible to make a more advanced authenticity determination.

  According to the present invention, since the hologram pattern is directly used for writing the magnetic signal, there is an advantage that it is not necessary to separately write the signal. At the same time, by combining with hologram technology, an unprecedented security element is obtained, and it is extremely difficult to forge it.

  According to the present invention, whether it is an amorphous magnetic material or a crystalline ferromagnet, it is possible to maintain the characteristic magnetic characteristics by devising the diffraction grating pattern of the hologram, read this, and determine the authenticity It becomes. Further, by changing the diffraction grating pattern or writing an image in the form of a pattern in the hologram area in advance, it is possible to hold magnetic data corresponding to the pattern in the information recording medium. Also, evaluating the magnetic characteristics of the information recording medium evaluates the performance of both the magnetic material and the hologram. Therefore, if the information recording medium according to the present invention is forged, it is possible to evaluate both the workmanship of the hologram and the workmanship of the magnetic material by evaluating the magnetic characteristics of the forged product, both of which are not satisfied. Therefore, it is very difficult to forge and high security can be realized.

Example 1
As shown in FIG. 1A, a diffraction grating 4 for forming a hologram pattern is provided on the entire surface of a substrate 2 for an information recording medium 1, and an Fe-based ferromagnetic thin film 3 is formed thereon with a film thickness of 0.2 μm. Then, the magnetic signal was examined. The magnetic signal referred to here indicates a waveform obtained when AC excitation is performed by the reader shown in the block diagram of FIG. FIG. 1B is a partially enlarged view of the end surface of the information recording medium 1 shown in FIG. In FIG. 2, 11 is an object to be determined such as the information recording medium 1 shown in FIG. 1, 12 is an alternating current excitation power source, 13 is an excitation coil, 8 is a magnetic head, 9 is an amplifier, 10 is an oscilloscope, and 5 is a reading. Direction (direction of excitation magnetic field). As the traveling drive mechanism for traveling one of the information recording medium 1 and the magnetic head 8 along the direction perpendicular to the scanning direction with respect to the other, a normal appropriate traveling drive mechanism can be used. The illustration is omitted. In this example, the mirror surface of a silicon wafer was used as the base material 2 in order to confirm the magnetic behavior, and the diffraction grating 4 was formed of a positive resist for semiconductor processes. Actual holograms used in security are often made of the same material resin for both the base material and diffraction grating, but the effect of the base material material on the magnetic properties is low, rather it depends greatly on the shape of the actual hologram. A similar pulse wave can be obtained with a hologram. The diffraction grating 4 forming the hologram is formed so that the concave / convex arrangement direction is parallel to the magnetic flux of excitation, the line width α of the diffraction grating 4 is 2 μm, the space width β is 1 μm, and the height γ is 0.4 μm. It was. This pattern produced a unique interference color of the hologram. The magnetic characteristics are affected by the area A of the diffraction grating 4 of the hologram, and a pulse wave appears as shown in FIG. FIG. 3B is a partially enlarged view of FIG. In Comparative Example 1 shown in FIG. 14 having no hologram region, a pulse having a small peak value can be obtained as shown in FIG. 15 even if the magnetic material is formed as in Example 1, and as shown in FIG. A pulse with a large peak value does not appear. FIG. 4 is a modification of FIG. 1A, FIG. 4A is an example in which a regular curved portion 4a is provided on the diffraction grating 4, and FIG. 4B is a diagram of FIG. ), And the peak value of the pulse wave slightly decreases at the regular curved portion 4a provided on the diffraction grating 4. As shown in FIG. 5, if the concavo-convex arrangement of the diffraction grating 4 forming the hologram is oriented in many directions, the magnetic signal will be the same even when reading along each direction, and there is almost no anisotropy and the reading direction is set. Any magnetic hologram information recording medium can be obtained.

(Example 2)
As in Example 1, a silicon wafer was used as the base material 2 to form a hologram. However, in Example 2, as shown in FIG. 6A, the area 6 with the hologram area (A area) and the hologram area are absent. There are areas 7 (flat areas X), which are arranged alternately. An Fe-based ferromagnetic thin film 3 was formed thereon with a film thickness of 0.2 μm, and changes in magnetic signals were examined. At this time, in the area 6 where the hologram area is located, the diffraction grating 4 is made parallel to the magnetic flux of excitation. It was examined what happens to the magnetic signal in the area 6 with the hologram area shown in the partially enlarged view of FIG. 6B and the area 7 without the hologram area shown in the partially enlarged view of FIG. The reading device is the device shown in the block diagram of FIG. The line of the diffraction grating 4 was 1 μm, the space was 1 μm, and the height was 0.4 μm. It can be seen that the interference color unique to the hologram is seen by this pattern and exists in a stripe shape. In Example 2, the magnetic characteristics changed as shown in FIG. 7A and an enlarged view of FIG. 7B corresponding to the presence or absence of the hologram region (FIG. 7). That is, a large pulse appears as shown in FIG. 7B in the area 6 (A area) where the hologram area is present, and a pulse is also broadened as shown in FIG. 7C in the area 7 (X area) where there is no hologram area. The peak value also became smaller. In this way, the hologram pattern can be read visually or with an optical reading device, and at the same time, the corresponding magnetic signal can be read.

(Example 3)
As in Example 1, a silicon wafer was used as the base material 2, and as shown in the partially enlarged views of FIGS. 8 (a), 8 (b), and 8 (c), the unevenness of the diffraction grating 4 forming the hologram pattern was observed. Diffraction gratings 4 with different angles in the arrangement direction were provided in the same plane, and an Fe-based ferromagnetic thin film 3 was formed thereon with a thickness of 0.2 μm, and changes in magnetic signals were examined. At this time, two types of hologram patterns are rotated at an angle of 90 °. The magnetic reading signal is a waveform obtained when AC excitation is performed by the reading device shown in the block diagram of FIG. The lines of the diffraction grating 4 are 1 μm, the space is 1 μm, and the height is 0.4 μm, and only the angles are different. The interference color peculiar to the hologram is seen by this pattern, and the hue is different between the hologram regions having different angles, and the stripe can be confirmed. As shown in the partially enlarged views of FIG. 9 (a) and FIGS. 9 (b) and 9 (c), the magnetic characteristics correspond to the angle in the arrangement direction of the concave and convex portions of the diffraction grating 4 forming the hologram pattern. Appeared. That is, when the pattern is 0 ° (reading direction and diffraction grating 4 are parallel: A region), a large pulse appears as shown in FIG. 9B, and 90 ° (reading direction and diffraction grating is orthogonal: B region). Sometimes, as shown in FIG. 9 (c), the pulse also became broad and the crest value decreased. The hologram pattern can be read visually or with an optical reading device, and at the same time, the corresponding magnetic signal can be read.

Example 4
This is an example of a hologram having a circular pattern using a silicon wafer as the base material 2 as in the first embodiment. As shown in FIG. 10 (a) and FIG. 10 (b), which is a partially enlarged view, the angle of the hologram diffraction grating 4 is parallel to the excitation magnetic flux in a uniform hologram region whose angle is 45 ° with the excitation magnetic flux. A circular hologram region having an angle of the diffraction grating 4 was provided. An Fe-based ferromagnetic thin film was formed thereon with a thickness of 0.2 μm, and the change in magnetic signal was examined. The magnetic signal is a waveform obtained when AC excitation is performed by the reader shown in the block diagram of FIG. In this embodiment, by making the reading width of the magnetic head 8 larger than the width of the information recording medium, the design of the hologram can be read by magnetic signal output. The line of the diffraction grating 4 is 1 μm, the space is 1 μm, the height is 0.4 μm, and only the common angle is different. The interference color peculiar to the hologram was seen by these patterns, and the circular hologram area A and other areas C had different colors. As for the magnetic characteristics, a pulse wave corresponding to the hologram pattern appeared as shown in FIGS. 11A and 11B and 11C which are enlarged views thereof. That is, when the pattern is 45 ° (reading direction and diffraction grating 4 is 45 °), a small pulse appears, and as the circular pattern of 0 ° (reading direction and diffraction grating 4 is parallel: area A) appears, the pulse Gradually increased and decreased, and after passing the symbol, the original small pulse was obtained as shown in FIG. 11 (c). In this way, a circular hologram pattern can be read visually or with an optical reading device, and at the same time, a corresponding magnetic signal can be read.

  In the above embodiment, the magnetic characteristics were confirmed only for a simple hologram pattern. However, the information recording medium according to the present invention is also characterized by the pattern for complex patterns such as a hologram pattern for reproducing a stereoscopic image often used in security. It can be easily inferred that it can be distinguished from other magnetic films without using special materials.

(Example 5)
This is an example of a hologram pattern using a silicon wafer as the base material 2 and having the design of the letter “A” as in the first embodiment. As shown in FIG. 12, the letter “A” having the concave / convex arrangement angle of the diffraction grating 4 parallel to the excitation magnetic flux in a uniform hologram area where the concave / convex arrangement angle of the hologram diffraction grating 4 is 45 ° with the excitation magnetic flux. A hologram region having a shape of “is provided. An Fe-based ferromagnetic thin film was formed thereon with a film thickness of 0.2 μm. The line width of the diffraction grating 4 is 1 μm, the space width is 1 μm, and the height is 0.4 μm. The interference color peculiar to the hologram is seen by these patterns, and the hologram area having the shape of “A” and other areas have different colors. The reading device shown in the block diagram of FIG. 2 is used, and the reading width of the magnetic head is made sufficiently smaller than, for example, the letter “A” as shown in FIG. The magnetic heads 8 of CH1 to CH20 are arranged so as to be divided, and for example, (1) (2) (3)... (14) Asynchronous or continuous in which the information recording medium 1 is temporarily stopped at regular intervals. In order to generate a read output pulse output by performing a scan that sequentially switches CH1 to CH20 of the magnetic head 8 during the temporary stop using an appropriate switching circuit not shown in FIG. When the reading device is operated, a pulse wave appears corresponding to the shape of “A” as shown in FIG. That is, a small pulse appears when the pattern is 45 ° (reading direction and diffraction grating is 45 °), and a pulse appears in the region where the pattern of the letter “A” whose pattern is 0 ° (reading direction and diffraction grating is parallel) appears. Becomes larger and passes through the letter “A” and becomes the original small pulse. The scanning may be performed by moving the single magnetic head 8 along the fixed direction, and the driving of the information recording medium 1 is about 1/10 of the scanning speed in the fixed direction. The traveling speed is low as described above, and continuous driving can be adopted in addition to the previous start-stop driving. As the traveling drive mechanism for traveling one of the information recording medium 1 and the magnetic head 8 along the direction perpendicular to the scanning direction with respect to the other, a normal appropriate traveling drive mechanism can be used. The illustration is omitted. As described above, the hologram signal “A” can be read visually or with an optical reading device, and simultaneously the corresponding magnetic signals can be read.

  That is, with such a configuration, the unevenness of the base material (2) and the diffraction grating (4) regularly or irregularly provided on the surface of the base material is reflected by the reflected light from the unevenness of the diffraction grating. A hologram thin film (A) formed so as to be observed as a pattern, and a ferromagnetic thin film (3) formed on the hologram light, and the ferromagnetic thin film as management information for preventing forgery The information recording medium (1) having characteristic magnetic properties corresponding to the hologram pattern or the shape pattern of the hologram area as a target, the hologram area of the information recording medium along a certain direction (5) Excitation means (12, 13) for AC excitation, and magnetic head means for sequentially scanning out the output signal from the information recording medium by the AC excitation along the fixed direction of the hologram area. 8) and continuously or stepwisely moving one of the information recording medium and the magnetic head means at a traveling speed sufficiently lower than the scanning speed along the feeding direction perpendicular to the scanning direction with respect to the other. Travel driving means for traveling driving; and visual display means (10) for visually displaying the output signal from the magnetic head means in synchronization with the sequential scanning and the traveling driving, the hologram pattern or the hologram region An information reading device formed so that a signal pattern corresponding to the shape pattern is observed by the visible display means is realized.

(Comparative Example 1)
As shown in FIG. 14A and a partially enlarged view of FIG. 14B on the base material 2 on which the diffraction grating 4 is not formed, an Fe-based ferromagnetic material is used for the silicon wafer and the magnetic body. A magnetic film having a thickness of 0.2 μm was formed (X region), and the magnetic characteristics were confirmed. FIG. 15A and a partially enlarged view of FIG. 15B show magnetic signals in the same direction as in the first embodiment. It can be seen that the magnetic signal in the X region obtained is a broad pulse, which is clearly different from the case where the hologram region is present.

  16 (a) and 16 (b) are examples in which the information recording medium of the present invention is adhered to the surface of a thin and high-value-added product made of plastic, paper such as prepaid cards and gold vouchers, and pasted by a method such as transfer. It is.

It is the schematic diagram (a) of Example 1, and a partial enlarged view (b). 2 is a block diagram illustrating a configuration example of a reading device in Examples 1 to 4 and Comparative Example 1. FIG. FIG. 2 is a magnetic signal (a) obtained from the recording medium of Example 1 and a partially enlarged view thereof. It is the perspective view (a) which shows the modification of Example 1, and its magnetic signal (b). 2 is a schematic perspective view showing an example in which hologram patterns are arranged in a plurality of directions in Example 1. FIG. It is the schematic diagram (a) of Example 2, and a partially enlarged view (b) (c). It is the magnetic signal (a) obtained from the recording medium of Example 2, and its partial enlarged view (b) (c). It is the schematic diagram (a) of Example 3, and partial enlarged views (b) and (c). It is a magnetic signal (a) obtained from the recording medium of Example 3, and a partial enlarged view (b) (c). It is the schematic diagram (a) and enlarged view (b) of Example 4. It is a magnetic signal (a) obtained from the recording medium of Example 4, and a partial enlarged view (b) (c). FIG. 10 is a perspective view for explaining the structure of a recording medium of Example 5 and a reading device for reading the magnetic signal. It is a figure which shows the example of a magnetic signal obtained from Example 5. It is the schematic diagram (a) of Comparative Example 1, and a partially enlarged view (b). FIG. 6 is a magnetic signal obtained from the recording medium of Comparative Example 1 and a partially enlarged view (b). It is a schematic perspective view which shows an example when the information recording medium by this invention is affixed on a card | curd (a) and gold | metal | money ticket (b).

Explanation of symbols

1 Information recording medium 2 Base material 3 Ferromagnetic film (ferromagnetic thin film)
4 Diffraction gratings 4a and 4b Curved portion 5 Reading direction (direction of excitation magnetic field)
6 Area with hologram (existing area)
7 Area without hologram (None area)
8 Magnetic Head 9 Amplifier 10 Oscilloscope 11 Object to be Determined (Information Recording Medium)
12 Excitation power supply 13 Excitation coil 14 Prepaid card 15 Gold vouchers

Claims (1)

A substrate;
A hologram region formed such that irregularities of the diffraction grating regularly or irregularly provided on the surface of the substrate are observed as a hologram pattern by reflected light from the irregularities of the diffraction grating;
A ferromagnetic thin film formed of an amorphous ferromagnetic material on the hologram region;
An information recording medium in which characteristic magnetic properties corresponding to the hologram pattern or the shape pattern of the hologram region are held in the ferromagnetic thin film as management information for preventing counterfeiting,
The hologram area is divided into several parts so that hologram patterns are arranged in multiple directions, the orientation of the diffraction grating is changed in each divided area, and the anisotropy is arranged.
An information recording medium characterized by the above.

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