JPH0896098A - Information recording medium and information recording/ reproducing device therefor - Google Patents

Abstract

PURPOSE: To obtain a high forger prevention effect by recording information by successively laminating a metallic thin film layer, an infrared-ray absorption layer and a transparent protective layer on a medium base material and melting the metallic thin film layer. CONSTITUTION: A magnetic card MC is composed by successively laminating a metallic thin film layer 2, an infrared-ray absorption layer 3, a hiding layer 4, a transparent protective layer 5 and a magnetic recording part 6 on the one surface of medium base material 1. On the metallic thin film layer 2, a data recording pattern 7 and a clock recording pattern 8 for synchronization are formed by the irradiation with a thermal beam such as laser beam, etc., in accordance with a prescribed information pattern. In this case, laser beam is collected on the infrared-ray absorption layer 3 from the side of the transparent layer 5 for the wavelength of the laser of the magnetic card MC. As a result, a recording is performed because the laser beam projected on this infrared-ray absorption layer 3 is absorbed in the infrared ray absorption exothermic agent contained in the infrared-ray absorption layer 3, light energy is converted into heat energy and the metallic thin film layer 2 is melt due to this heat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium and an information recording / reproducing apparatus therefor, and more particularly to an information recording medium excellent in forgery prevention and an information recording / reproducing apparatus therefor.

[0002]

2. Description of the Related Art Recently, an information recording medium (hereinafter referred to as a card) such as a cash card or a credit card, which is provided with a belt-shaped magnetic recording portion on one side, or a magnetic recording layer such as a telephone card is provided. Magnetic cards such as things are becoming popular. Along with this, a card provided with a heat-sensitive recording layer which can be recorded by using a heat-sensitive recording technique has been issued.

However, magnetic recording has a problem in durability and information retention such that information is written and read by sliding contact with a reproducing head and recorded information is erased by an external magnetic field.

In order to solve such a problem, therefore, a card having a metal piece embedded in the middle of the card for recording information or a card having a metal vapor deposition layer is partially covered with the metal vapor deposition layer according to a predetermined pattern. An information pattern is formed by removing the information, a magnetic field is applied to the information recording portion of the card, and the induced voltage or eddy current signal is detected by a pickup coil or the like, so that the information recorded on the card is contactlessly contacted. Devices and methods for reading have been proposed.

That is, the above magnetically recorded information has a risk of rewriting or erasing data due to the approach of an external magnetic field, but in this method, it may be affected by the external magnetic field and environmental conditions. Without, the long-term stability of data can be secured.

As a conventional technique of this kind, there is one disclosed in, for example, Japanese Patent Laid-Open No. 55-146570.

That is, the magnetic recording portion is provided on a part of a thin flat plate made of plastic or the like as shown in FIG. 15 (a), and magnetic recording as shown in FIG. 15 (b) is not performed. Using a magnetic card MC in which a large number of small non-magnetic metal pieces 50 such as aluminum arranged in the plate in the vertical and horizontal directions according to a predetermined rule are embedded in the plate, FIG.
As shown in (c) and FIG. 15 (d), the card MC
A large number of magnetic poles 62, 64 wound with windings 60, 61 are provided opposite to the front and back of the small metal piece 50, a high-frequency voltage is applied to one winding 60, and the other winding 61 is connected to the inside of the card MC. A reading device for detecting the presence or absence of the small metal piece 50 by an induced voltage is described.

However, the method of embedding a small metal piece is high in the manufacturing cost of the card, and the method shown in FIG. 15 (e) in which a large number of magnetic poles having windings are provided requires a large-scale reading device, and the device price is high. There is a problem that is high.

On the other hand, another conventional technique is disclosed in, for example, Japanese Patent Laid-Open No. 05-294095.

That is, as shown in FIG. 16B, in the magnetic card MC in which the medium base material 1 is provided with the metal vapor deposition layer 53 having a predetermined area, the metal vapor deposition layer 53 is formed according to a predetermined pattern. , A method of reading an information pattern formed by a combination of a non-removed portion 56 where the metal vapor deposition layer 53 is present and a partially removed removed portion 55, which is partially removed by a thermal recording head.

According to this method, as shown in FIG. 16 (a), a predetermined information pattern is obtained by calculating the difference in eddy current between the non-removed portion 56 where the metal vapor deposition layer 53 is present and the removed portion 55 where it is not present. By scanning with the sensor head S for detection and detecting the removed portion 55 from the difference in the detected eddy current, as shown in FIG. 16C, information is read as the output voltage difference of the sensor coil.

In this case, the sensor head S is provided with an oscillation coil (not shown), and this oscillation coil operates so as to generate a high frequency magnetic field. The sensor head S is moved along the information pattern of the magnetic card MC. Then, the scan for reading the recorded information is executed by moving the card at a constant speed.

However, in the above card, the recording of information is performed by bringing the thermal recording head into contact with the card, so that the protective layer cannot be thickened and the card cannot have sufficient durability. Also, due to the widespread use of thermal printers, it cannot be said that there is a sufficient effect for additional writing. Further, in the information reading method as described above, since the card does not have information for reading synchronization, the reading device needs a constant-speed carrier synchronization mechanism when reading the recorded information pattern, which is equivalent to that. However, the reading device is expensive.

[0014]

As described above, in the conventional card and the information reading method thereof, sufficient durability of the card cannot be obtained, and sufficient effect cannot be obtained for additional writing and falsification. Card transport speed (scanning speed)
However, there is a problem that it becomes difficult to read information when the value changes, and the reading device is large and expensive.

The present invention has been made to solve the above-mentioned problems, and it is possible to obtain a sufficient durability by thickening the protective layer of the card and prevent additional writing and falsification. Provided is an inexpensive and simple information recording medium capable of reliably reading information even if the medium transport speed (scanning speed) changes, and having a high anti-counterfeiting effect, and an information recording / reproducing apparatus therefor. The purpose is to do.

[0016]

In order to achieve the above object, first, in the invention according to claim 1, on a medium substrate,
A metal thin film layer, an infrared absorption layer, and a transparent protective layer are sequentially laminated,
It comprises an intermediate layer recording area for recording information by melting the metal thin film layer.

Further, in the invention according to claim 2, in the information recording medium of the invention according to claim 1, information is recorded by providing a melted portion and a non-melted portion in the metal thin film layer on the medium substrate. By irradiating a heat beam from the transparent protective layer side, the metal thin film layer is selectively melted to record information.

Further, in the invention according to claim 3, in the information recording medium of the invention according to claim 1 or claim 2, between the metal thin film layer and the transparent protective layer, it is transparent to infrared rays and ultraviolet rays. A concealing layer or a printed layer is provided, or a printed layer of visual information is provided on the surface of the transparent protective layer.

In particular, as the infrared absorbing heat generating agent in the infrared absorbing layer, a polymethine-based agent which loses its infrared absorbing heat generating function by irradiating with light having a wavelength in the ultraviolet region above a predetermined level after irradiation with a heat beam. It shall consist of materials.

Further, the information recorded on the metal thin film layer is recording information composed of a series of regularly arranged synchronous clock recording patterns for reading and an encoded data recording pattern.

On the other hand, in the invention according to claim 6, in the information recording / reproducing apparatus for reading the recorded information of the information recording medium according to any one of claims 1 to 4, there is provided an information recording medium. At least one set of means for reading information by converting the magnetic field strength that changes depending on the presence or absence of a metal film into an electric signal, which is composed of an AC magnetic field generating coil and a pickup coil that are arranged opposite to each other with a predetermined gap on both sides Consists of

In the invention according to claim 7, the information recorded in the metal thin film layer of the information recording medium of the invention according to any one of claims 1 to 4 is regularly arranged. In an information recording / reproducing apparatus for reading record information composed of a series of read synchronous clock recording patterns and encoded data recording patterns, the information recording medium is provided by a conveying means for relatively moving the information recording medium and the reading means. Is provided with means for reading the recorded information by the pickup coil, converting it into a digital signal, and extracting the data.

Further, in the invention according to claim 8, the information recording / reading is performed to read the record information recorded on the metal thin film layer of the information recording medium of the invention according to any one of claims 1 to 4. In the reproducing apparatus, a magnetic recording area for recording magnetic information is also provided on the surface or the intermediate layer of the information recording medium, and a means for decoding the information recorded on the metal thin film layer is provided, and the decoding means decodes the information. The recorded information and the same information recorded in the magnetic recording area are compared and referenced.

Furthermore, in the invention according to claim 9, the information is regularly arranged as the information recorded on the metal thin film layer of the information recording medium of the invention according to any one of claims 1 to 4. In an information recording / reproducing apparatus for reading recorded information consisting of a series of read synchronous clock recording patterns and encoded data recording patterns,
Recording means for recording synchronous clock information at the time of information recording,
The information recording medium is moved by the conveying means that relatively moves the information recording medium and the reading means, so that the pickup coil reads the recorded information, converts it into a digital signal, and extracts the data.

[0025]

Therefore, in the information recording medium and the information recording / reading apparatus of the present invention, the infrared absorbing layer is irradiated with a heat beam such as a laser beam without contact with the infrared absorbing layer through the protective layer transparent to infrared rays. By melting the metal thin film layer, it becomes possible to thicken the protective layer, so that sufficient durability can be obtained.

Further, by irradiating the infrared absorbing heat-generating agent of the infrared absorbing layer with visible light or ultraviolet rays of a predetermined level or higher, the infrared absorbing heat generating function is lost, and after the information pattern is recorded, it is exposed to ultraviolet rays.
Since it becomes possible to make the melting of the metal thin film layer difficult by lowering the sensitivity to the heat beam, it is possible to prevent additional writing and falsification.

Further, by recording the synchronous clock at the time of reading in synchronization with the data in the information pattern recording portion of the metal thin film layer, even if the transport speed (scanning speed) of the information recording medium changes. The information can be read reliably. Further, by recording the recording data by various methods, the data cannot be easily read even if the slit is read.

Further, a concealing layer or a printing layer transparent to infrared rays and ultraviolet rays is provided between the metal thin film layer of the information recording medium and the transparent protective layer, or a visual information printing layer is provided on the surface of the transparent protective layer. By providing the above, it becomes possible to make information recorded on the metal thin film layer unreadable with visible light, so that it is difficult to visually recognize and it becomes difficult to read the recorded pattern.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration example of a magnetic card which is an information recording medium according to the present invention. FIG. 1A is a sectional view of the magnetic card, and FIG. 1B is a plan view of the magnetic card. Each figure is shown.

That is, as shown in FIG. 1, in the magnetic card MC of this embodiment, the metal thin film layer 2, the infrared absorbing layer 3, the concealing layer 4, the transparent protective layer 5, are formed on one surface of the medium substrate 1. The magnetic recording unit 6 is sequentially laminated.

As shown in FIG. 1B, the metal thin film layer 2 has a data recording pattern (hereinafter referred to as a data slit) 7 and a synchronization clock recording pattern (hereinafter referred to as a clock) according to a predetermined information pattern. The slit 8) is formed by irradiation with a heat beam such as a laser beam (not shown).

The width and interval of the slits are defined by the size of the sensor of the information reproducing apparatus (not shown), that is, the size of the pickup coil. Then, in this example, the dimension in the height direction of the slit is about twice as large as the width.

On the other hand, the medium substrate 1 has, for example, a thickness of 1
Although 50 μm polyvinyl chloride (PVC) is used, its thickness is not particularly limited as long as the required strength is obtained.

Any other material can be used as long as it has mechanical strength and heat resistance. For example, a resin such as polyethylene terephthalate (PET), a synthetic resin such as an epoxy resin or a polycarbonate, an aromatic polyamide (aramid), polyester, glass, synthetic paper, or wood can be used.

The metal thin film layer 2 is formed by depositing tin, for example, to form a film having a thickness of 500 angstrom. The thickness of this deposited film is preferably 400 angstroms to 2000 angstroms.

As the other metal, a simple substance, an alloy or a metal compound of a low melting point metal such as bismuth, indium, lead, cadmium, tellurium, aluminum or silver can be used. The film may be formed by a method of attaching the metal foil, instead of vapor deposition.

Further, the infrared absorbing layer 3 is composed of an infrared absorbing exothermic agent and a binder. As the infrared absorbing exothermic agent,
A polymethine cyanine dye is used. In addition, azo dyes, naphthoquinone dyes, anthraquinone dyes, and the like can be used.

As the binder, polyester resin,
Cellulose resins such as ethyl cellulose, methyl cellulose, cellulose acetate, hydroxyethyl cellulose, hydroxypropyl cellulose, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, vinyl resins such as polyacrylamide, and other polymethyl acrylate, polyacrylic acid, etc. Acrylic resin, polyolefins such as polyethylene and polypropylene, polyacrylate resins, epoxy resins and phenol resins can be used.

In this example, a solvent composed of 2% by weight of cyanine dye, 70% by weight of solvent and 28% by weight of polyester resin was applied on the metal thin film layer 2 and dried to form a coating having a thickness of 0.5 μm to 5 μm. The film. Preferably, the coating film has a thickness of 1 μm to 3 μm.

On the other hand, the concealing layer 4 can be made of a material having a high transmittance in the infrared and ultraviolet regions, which are the wavelength regions of the semiconductor laser, and having a suitable opacity to visible light.

As the material, it is possible to use, for example, yellow, magenta, and cyan optical filter materials. In addition, the same effect can be obtained by a method such as providing pattern printing. In this example, a colorant for an optical filter whose mixing ratio is selected so as to increase the transmittance of ultraviolet rays is used.

The masking layer 4 formed by coating and drying on the infrared absorbing layer 3 is a coating film having a thickness of 0.5 μm to 5 μm. Preferably, the coating film has a thickness of 1 μm to 3 μm.

The transparent protective layer 5 has a thickness of 6 μm to 10 μm.
It is made of 0 μm vinyl chloride. The thickness is preferably 10 μm to 150 μm. In this example, the thickness is limited to 70 μm.

Examples of other materials include polyethylene terephthalate (PET), polyamide, polyimide, polycarbonate, cellulose ester, fluorinated polymer, polyacetal, polyolefin, aramid,
A material having good wear resistance and heat resistance such as a fluororesin can be generally used.

Further, the magnetic recording portion 6 is formed as a strip having a width of about 6 mm on the surface of the transparent protective layer 5. This is because it is not appropriate to provide the magnetic recording layer 6 in the inner layer of the magnetic card MC because the transparent protective layer 5 is thick in this example. Of course, the magnetic recording layer 6 may be recorded on the magnetic recording layer 6 with a sufficient gain so that the magnetic recording layer 6 can be read without error, and the magnetic recording layer 6 may be provided on the inner layer of the magnetic card MC.

Next, recording of the data slit 7 and the clock slit 8 on the metal thin film layer 2 of the magnetic card MC is as follows.
Do as follows.

That is, the magnetic card MC is irradiated with a focused laser beam from the transparent protective layer 5 side of the magnetic card MC, and the clock slit 7 and the data slit 8 having a width of about 2 mm and a height of 2 mm to 4 mm. Are formed in a predetermined recording format.

The laser used here has a wavelength of 830 nm.
The spot diameter of the laser beam, which has an optical power of 200 mW in condensing and is condensed by using an appropriate optical system (not shown), is about 100 μm × 100 μm.

As a result, the number of data slits 7 formed by melting the metal is changed from 16 slits to 20 slits per row in the 54 mm × 86 mm magnetic card MC. Also, when multiple data slit rows are provided, the maximum number of slit rows is 6, and the presence or absence of slits is 1
With bits, 120 bits can be recorded at the maximum. If one slit has multiple levels,
The information amount is obtained by multiplying the above information amount by the number of levels.

Next, the principle of laser irradiation recording on the magnetic card MC having the metal thin film layer 2 will be briefly described.

In the method of forming an information pattern with the thermal recording head, in the magnetic card MC having the structure shown in FIG. 16B, the thermal recording head (not shown) is brought into contact with the card surface from the side of the thin protective layer to heat the recording surface. Energize the heating element of the recording head. The heat generated by this energization is the protective layer 5
4 is conducted to the metal vapor deposition layer 53 via
3 is heated and melted, and holes are formed in the heated portion.

On the other hand, in the laser irradiation recording, as a basic structure of the magnetic card MC, as shown in FIG.
A medium thin film layer 2, an infrared absorbing layer 3, and a wear-resistant transparent protective layer 5 which are sequentially laminated on one surface of the medium substrate 1 are used.

The metal thin film layer 2 is melted by irradiating a focused laser beam LB instead of the thermal recording head and melting the metal by the heat to form a hole in the metal thin film layer 2. Due to the surface tension, the molten metal becomes a state in which small metal particles called ball-up are aggregated.

That is, as shown in FIG. 2B, the laser beam LB is focused on the infrared absorption layer 3 from the protective layer 5 side which is transparent to the laser wavelength of the magnetic card MC.
Then, the laser light applied to the infrared absorbing layer 3 is absorbed by an infrared absorbing heat generating agent (not shown) included in the infrared absorbing layer 3 to convert light energy into heat energy, and this heat causes the metal thin film layer 2 to By melting, the information pattern is recorded as in the recording portion (P) 9 shown in FIG. Then, after the recording is finished, by irradiating the entire surface of the magnetic card MC with a predetermined amount of ultraviolet rays by an ultraviolet ray irradiator (not shown), the infrared absorbing heat generating function of the infrared absorbing heat generating agent is lost and the sensitivity to the laser beam is lost. Let

Depending on the application, the concealing layer 4 may be omitted, and if necessary, a print layer for forming a visible image may be provided.
As shown in (a), a concealing layer 4 and a printing layer which are transparent to infrared rays and ultraviolet rays are provided between the metal thin film layer 2 of the magnetic card MC and the transparent protective layer 5, and as shown in FIG. 2 (c). As described above, the information recorded on the metal thin film layer 2 can be hidden by a method of providing the printed layer 0 of the visible information on the surface of the transparent protective layer 5.

Next, regarding the information recording / reproducing apparatus for the magnetic card MC according to the present embodiment, when reading information provided on a general magnetic card, the reading principle will be briefly described with reference to FIG. explain.

Basically, when a metal piece is placed in a magnetic field whose change in magnetic field strength is a function of time, the magnetic field applied in the plane perpendicular to the direction of the magnetic field is weakened in the metal. It utilizes that current flows in the direction.

That is, as shown in FIG. 3A, in order to generate an external magnetic field, an AC voltage is applied to the AC magnetic field generating coil 11 by the AC voltage source 10 to generate a magnetic field. Further, as the metal piece, the magnetic card M having the metal thin film layer 2 is used.
At C, a magnetic card MC in which an information slit is recorded and a part of the metal thin film layer 2 is removed is arranged with its surface oriented in a direction perpendicular to the direction of the magnetic field. With such an arrangement, the magnetic flux is in the direction of penetrating the magnetic card MC. At this time, the magnetic flux passing through the portion where the metal film does not exist, that is, the portion where the metal thin film layer 2 is removed, passes through the removed portion as it is, and the magnetic flux density does not change. However, in the portion where the metal film exists, the magnetic flux penetrating the metal thin film layer 2 is weakened by the generation of the induced current as described above.

In this way, the presence or absence of the metal film can be detected by the strength of the magnetic field. Therefore, the slit-shaped information recorded on the magnetic card MC can be read by detecting the change in the magnetic field strength due to the presence or absence of the metal film with the inductor type probe, that is, the pickup coil 12. This signal appears as a change in the strength of the alternating magnetic field generated by applying an alternating voltage to the alternating magnetic field generating coil 11. At that time, for the pickup coil 12,
When the magnetic card MC is moved at a certain speed, the terminal voltage of the pickup coil 12 changes with the movement of the magnetic card MC depending on the presence or absence of the slit. The detection signal 13, which is the terminal voltage of the pickup coil 12, is a signal in which a voltage amplitude change as a magnetic field strength change is superimposed on an AC signal as a carrier wave. And magnetic card MC
The information recorded in 1 is obtained by AM demodulating this superimposed signal.

FIG. 3B is a perspective view showing how information recorded on the magnetic card MC according to the present embodiment is read by the information recording / reproducing apparatus according to the present embodiment. In the figure,
For convenience of explanation, the coil on the back side of the magnetic card MC is shown transparently.

The data slit 7 and the clock slit 8 of the magnetic card MC shown in FIGS. 1 and 2 and the AC magnetic field generating coil 11 and the pickup coil 12, respectively, on the front and back sides of the magnetic card MC are provided in the magnetic card MC. Place them close to each other and face each other. In this case, the diameter of the pickup coil 12 for reading the information of the slit used in this embodiment is about 2 mm. The size of the AC magnetic field generating coil 11 is not particularly limited, but is about 2 mm.

Next, a method of reproducing information recorded on the metal thin film layer 2 will be described.

First, an AC voltage is applied from the AC voltage source 10 to the AC magnetic field generating coil 11. In this case, the applied frequency is preferably several kilohertz to several hundred kilohertz. In this embodiment, it is set to 100 kHz.

Next, the magnetic card MC is conveyed in the row direction of the information slits shown by the arrow D in the figure, and sequentially passes through the slit rows recorded in the metal thin film layer 2.

In this case, the AC magnetic field generating coil 1
When a metal film exists between 1 and the pickup coil 12, the magnetic field is weakened by the current generated in the metal film, the voltage amplitude induced in the pickup coil 12 is small, and the voltage amplitude is set to Vd.

In the portion where the metal film is removed, the AC voltage suitable for the coupling between the AC magnetic field generating coil 11 and the pickup coil 12 is induced in the pickup coil 12 by the magnetic field strength generated by the AC magnetic field generating coil 11. To do. When this voltage amplitude is V0, Vd <V0.
In this way, the presence or absence of the metal film can be detected as a change in the amplitude of the AC voltage induced in the pickup coil 12.

In FIG. 3B, the signal detected by the pickup coil 12a located in the data slit 7 is Vd, and the signal detected by the pickup coil 12b located in the clock slit 8 is Vck.

On the other hand, the magnetic information recorded in the magnetic recording section 6 is read out as a voltage signal Vm by the magnetic head 14 at the same time as the information recorded in the metal slit. Although the AC magnetic field generating coil 11 and the pickup coil 12 are air core coils in this example, they may be cored coils.

FIG. 4 is a block diagram showing a schematic configuration example of the information recording / reproducing apparatus according to this embodiment.

That is, as shown in FIG. 4, with the controller CC for controlling the entire apparatus at the center, the CPUC
A memory M for storing a control program and work data, a writing laser head LH and a driver LD thereof, an ultraviolet irradiation mechanism UV, an AC magnetic field generating coil 11, an AC power supply 10 for exciting the same, and a pickup coil 12. And a detection signal processing circuit SP thereof, the magnetic information recording / reading magnetic head 14 and its driver MD, an operation panel P, a card carrying section CT for taking in, carrying, and discharging the magnetic card MC, and the like (not shown). It consists of an interface with external equipment.

Next, various information reading modes according to this embodiment will be described.

FIG. 5 shows a first information reproducing circuit according to the present invention.
It is a block diagram which shows the Example of. This circuit shows a part of the internal circuit of the signal processing circuit SP in FIG.

FIG. 6 is a timing chart of a data reading format by the information reproducing circuit of FIG.

In FIG. 6, the clock slits 8 are recorded at equal intervals and the same width. In this figure, the data slit 7 is formed such that the edge of the slit extending from the slit of the clock slit 8 to the metal film has the same width as the clock slit 8 with the data slit 7 as the center. Then, the data is read from the slit of the clock slit 8 at each edge of the slit that covers the metal film. The signals detected by the pickup coils 12a and 12b schematically show waveforms as a data detection signal 15 and a clock detection signal 16, respectively.

This signal is converted into a data signal 17 and a clock signal 18 which are digital signals by the information reproducing circuit shown in FIG. In FIG. 5, the pickup coil 1
The data detection signal 15 and the clock detection signal 16 detected by 2a and 12b are first detected by the envelope detection circuit 19
At, the carrier component is removed and only the amplitude change signal is extracted. After passing through the envelope detection circuit 19, the level comparator (a) 20 compares the amplitude level when the metal film exists and the amplitude level when the metal film does not exist with a prescribed threshold value. , 1,0 signals. After that, the level converter 21 converts the level into a TTL logic level. The processing up to this point is performed for both the data signal and the clock signal.

Next, the clock signal 18 is supplied to the clock input terminal CLK of the shift register 22 by the data signal 17
Are guided to the serial input terminals SI of the shift register 22 and read as parallel data 23 by a control unit (not shown).

In this recording pattern, the data slit 7
The presence or absence of "1" corresponds to recording bits 1 and 0, respectively. This method has an advantage that data can be read without error even if the width of the slit changes, as shown in the section (a).

FIG. 7 is a diagram showing a timing chart in two cases in which a clock is included in the data slit 7.

In both FIGS. 7A and 7B, the intervals between the data slits 7 are kept constant. Moreover, the width of the data slit 7 corresponds to the slit width in FIG. 5 when the logical value is 1, and the logical value 0 is defined as ½ of the former slit width. In FIG. 7, the leading edge of the slit is the clock.

The difference between FIG. 7 (a) and FIG. 7 (b) lies in the data detection method, which is the presence / absence of a slit by the internal clock 25 of the reproducing apparatus, or whether the data is read as the difference in the detection signal level. Even in this case, as in the case of FIG. 6, the variation of the slit width is allowed to some extent. These encodings have the advantage that the clock slit 8 need not be provided separately from the data slit 7.

Next, FIG. 8 is a block diagram showing a second embodiment of the information reproducing circuit for reading the recording pattern of FIG. 7A.

In FIG. 8, the slit information is detected by one circuit. The process from signal detection to level conversion is the same as in the case of FIG. In order to generate the clock signal 18 at the output stage of the level converter 21, the output of the level converter 21 is guided to the clock generation circuit 24. Further, the clock generation circuit 24 detects a difference in data slit width.
The internal clock 25 shown in (a) is generated and input to the clock input terminal CLK of the shift register 22. The subsequent processing is the same as in the case of FIG.

Next, FIG. 9 is a block diagram showing a third embodiment of the information reproducing circuit for reading the recording pattern of FIG. 7B.

In FIG. 9, the slit information is detected by one circuit. The level comparator (b) 26 of the upper data line of the circuit of FIG. 9 detects the change in the voltage signal induced in the pickup coil 12 by the width of the data slit 7 when the width is narrow and when it is narrow at the specified threshold value. Are set to output 1 and 0 respectively. On the other hand, the level comparator (c) 27 that generates the clock signal does not depend on the slit width and generates logic 1 and 0 depending on the presence or absence of the slit. Further, the clock signal 18 that has passed through the level converter 21 is given an appropriate delay by the delay circuit 28,
It is input to the clock input terminal CLK of the shift register 22.

Next, FIG. 10 is a block diagram showing a fourth embodiment of the information reproducing circuit for reading the recording patterns of FIGS. 11 and 12.

FIG. 11 is a diagram showing a timing chart of a recording pattern in which the data amount is increased by changing the width of the data slit 7 in a plurality of steps, and FIG. 12 is the same width. It is a figure which shows the timing chart of the recording pattern which increased the amount of information by making it the data slit 7 which changed the number of slits of these in multiple steps. In both FIGS. 11 and 12, since the detection signal has a multi-valued level, the allowance of the recording slit width is reduced as compared with the binary one. The maximum width of the data slit 7 is
Must be within detector dimensions.

In FIG. 10, the signal detection of the data line and the envelope detection are the same as in the case of the first embodiment shown in FIG. The clock line is the same as in the first embodiment shown in FIG. 5 from signal detection to level conversion.
The data line passing through the envelope detector 19 is voltage-amplified by the amplifier 29 and guided to the analog input terminal of the analog / digital (A / D) converter 30. The data becomes parallel digital data 23 by the A / D converter 30. The amplifier 29 may be included in the envelope detector 19.

Next, FIG. 13 is a configuration diagram showing a fifth embodiment of an information reproducing circuit for reading the recording pattern of FIG.

FIG. 14 is a timing chart of a recording pattern in which the data slit 7 is bi-phase encoded. In this recording pattern, the data signal 1
The exclusive OR of 7 and the clock signal 18 is obtained as the final information. Although the data is drawn so that it is recognized at the trailing edge of the clock slit 8 here, it may be read at the leading edge thereof.

The recording pattern reading of FIG. 13 is the same as that of the first embodiment shown in FIG. 5 from signal detection to level conversion. The level-converted data signal 17 and clock signal 18 are processed by an exclusive OR (EX-OR) circuit 3
1 is input to this exclusive OR (EX-OR) circuit 3
The output of 1 is the serial input terminal S of the shift register 22.
Guided by I. The clock signal 18 that has passed through the level converter 21 is guided to the clock input terminal CLK of the shift register 22 through the delay circuit 26. This delay is for avoiding a malfunction due to a glitch caused by a recording slit error or the like as a result of the exclusive OR.

As described above, the magnetic card M of this embodiment
In C and its information recording / reproducing apparatus, the infrared ray absorbing layer 3 is irradiated with a heat beam such as a laser beam through a protective layer 5 transparent to infrared rays in a non-contact manner to the metal thin film layer 2
Since it is made to melt, the transparent protective layer 5 can be made thicker because it does not rely on heat conduction as in a thermal recording head, and sufficient durability can be obtained. This is because the writing is non-contact and the intermediate layer can be recorded.

Further, the infrared absorbing heat generating agent of the infrared absorbing layer 3 is exposed to ultraviolet rays after recording the information pattern, assuming that the infrared absorbing heat generating function is lost by irradiating visible rays or ultraviolet rays of a predetermined level or higher. Therefore, it is possible to intentionally reduce the sensitivity to the heat beam and make it difficult to melt the metal thin film layer 2.

In the infrared absorbing exothermic agent used in this example,
The predetermined UV irradiation reduced the sensitivity of the medium to 1/10 or less of that before the UV irradiation. Therefore, the metal thin film layer 2 is at a level at which it cannot be already melted, and it becomes practically impossible to additionally write, whereby additional writing and tampering can be prevented.

Further, since the synchronous clock at the time of reading is recorded in the information pattern recording portion of the metal thin film layer 2 in synchronization with the data, the transport speed (scanning speed) of the magnetic card MC changes. Also, the information can be surely read.

Further, since the synchronizing clock is recorded on the magnetic card MC, a constant speed synchronizing mechanism is not required in the device for scanning the magnetic card MC to reproduce information, and the information recording / reproducing device is inexpensive. It can be anything.

Further, since the recorded data is recorded and read by the various methods as described above, even if the slit of the metal thin film layer 2 is simply read, the data cannot be easily read. Therefore, a high anti-counterfeit effect can be obtained.

Furthermore, between the metal thin film layer 2 of the magnetic card MC and the transparent protective layer 5, a concealing layer 4 or a printing layer transparent to infrared rays and ultraviolet rays may be provided, if necessary.
By printing the visual information printing layer 0 on the surface of the transparent protective layer 5, it becomes possible to make the information recorded in the metal thin film layer 2 unreadable by visible light, and therefore, the visual recognition cannot be performed. However, it is difficult to read the recorded pattern, and the security can be further improved.

The present invention is not limited to the above embodiment, but can be implemented in the same manner as described below.

(A) In any of the above-mentioned FIGS. 5 to 14, in order to increase the amount of information, a plurality of rows of data slits 7 are provided, and a set of pickup coils 12a for reading is used as a data row. You may provide it correspondingly.

(B) In the above embodiment, the metal thin film layer 2
The information recorded on the magnetic recording part 6 is not in the same data format as the information recorded on the magnetic recording part 6, but the data recorded on the metal thin film layer 2 is recorded on the magnetic recording part 6, The authenticity of the magnetic card MC may be determined by reading the same data twice and comparing and referring to the same data.

(C) In the above embodiment, the slits are recorded by changing the intervals of the plurality of data slits 7 having a uniform width which is almost equal to the size of the pickup coil 12 according to the recording information, and the slits are conveyed at a constant speed. However, by forming the recording pattern so that the change in the transmitted magnetic field intensity by the data slit 7 can be read, it becomes possible to read the information as the frequency change.

The writing and reading of the recording pattern in this case are performed by, for example, FSK (Frequency Shift).
t Keying) or MSK (Minimum)
According to the method of Shift Keying). According to this, the frequency of the carrier wave is shifted so that the frequency when the data is logic 1 is f1 and the frequency when the data is logic 0 is f2 (f1 << f2). And the magnetic card M
When reproduced as a C slit, it can be realized by changing the pitch of the slit.

[0104]

As described above, according to the present invention, information is obtained by sequentially laminating a metal thin film layer, an infrared absorbing layer and a transparent protective layer on a medium substrate and selectively melting the metal thin film layer. Equipped with an intermediate layer recording area for recording, the infrared absorbing heat generating agent of the infrared absorbing layer loses its infrared absorbing heat generating function by irradiating the infrared rays of a predetermined level or more after the heat beam irradiation, and records the recorded information of the metal thin film layer. At the time of reproduction, at least one set of reading means composed of an AC magnetic field generating coil and a pickup coil is provided, and a metal film (a metal film ( The magnetic field strength, which changes depending on the presence of slits, is converted into an electrical signal to read information, and the information recorded on the metal thin film layer is data information. Clock data having a series of synchronous clock patterns for reading which are arranged at equal intervals and data in which the clock patterns are arranged out of phase, and information recorded on the metal thin film layer is arranged at equal intervals. A slit portion having two different widths, a series of slit portions having different widths in which information recorded in the metal thin film layer is arranged at equal intervals, and information recorded in the metal thin film layer at equal intervals. , Consisting of a series of slits of different numbers arranged in series, consisting of a series of bi-phase code data pattern parts and clock pattern parts in which information recorded in the metal thin film layer is regularly arranged, metal thin film The information recorded on the layer includes the same data as the information recorded on the magnetic recording section, or the information recorded on the metal thin film layer and the magnetic recording section. The recorded information is not in the same data format, but the data for encoding the information recorded in the metal vapor deposition layer is recorded in the magnetic recording portion to record the synchronization clock, so that the protective layer of the card is protected. The thickness can be increased to obtain sufficient durability, additional writing and tampering can be prevented, information can be reliably read even when the medium transport speed (scanning speed) changes, and a high forgery prevention effect It is possible to provide an inexpensive and simple information recording medium and a device for recording / reproducing the information which can obtain the information.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of a magnetic card which is an information recording medium according to the present invention.

FIG. 2 is a sectional view showing an example of an information recording format in the magnetic card of the embodiment.

FIG. 3 is a schematic diagram showing a configuration example of an information recording / reproducing device for a magnetic card of the same embodiment.

FIG. 4 is a block diagram showing a configuration example of an information recording / reproducing apparatus for a magnetic card of the same embodiment.

FIG. 5 is a configuration diagram showing a first embodiment of an information reproducing circuit of the magnetic card of the same embodiment.

6 is a diagram showing a timing chart of a data reading format by the information reproducing circuit of FIG.

FIG. 7 is a diagram showing a timing chart when a clock is included in a data slit.

FIG. 8 is a configuration diagram showing a second embodiment of an information reproducing circuit for reading the recording pattern of FIG. 7 (a).

FIG. 9 is a configuration diagram showing a third embodiment of an information reproducing circuit for reading the recording pattern of FIG. 7 (b).

FIG. 10 is a configuration diagram showing a fourth embodiment of an information reproducing circuit for reading the recording patterns of FIGS. 11 and 12.

FIG. 11 is a diagram showing a timing chart of a recording pattern in which the amount of information is increased by using a data slit in which the data slit width is changed in a plurality of steps.

FIG. 12 is a diagram showing a timing chart of a recording pattern in which the amount of information is increased by using a data slit in which the data slit width is changed in a plurality of steps.

13 is a configuration diagram showing a fifth embodiment of an information reproducing circuit for reading the recording pattern of FIG.

FIG. 14 is a diagram showing a timing chart of a recording pattern in which a data slit is bi-phase encoded.

FIG. 15 is a schematic diagram showing a configuration example of a conventional magnetic card and its information reading device.

FIG. 16 is a schematic diagram showing a configuration example of a conventional magnetic card and its information recording / reading device.

[Explanation of symbols]

MC ... magnetic card, 1 ... medium substrate, 2 ... metal thin film layer,
3 ... Infrared absorbing layer, 4 ... Hiding layer, 5 ... Transparent protective layer, 6 ...
Magnetic recording unit, 7 ... Data slit, 8 ... Clock slit, 9 ... Recording unit, 10 ... AC voltage source, 11 ... AC magnetic field generating coil, 12 ... Pickup coil, 12a ... Data pickup coil, 12b ... Clock pickup coil, 13 ... detection signal, 14 ... magnetic head, D ... card transport direction, 15 ... data detection signal, 16 ... clock detection signal, 17 ... data signal, 18 ... clock signal, 19 ...
Envelope detection circuit, 20 ... Level comparator a, 21 ... Level converter, 22 ... Shift register, 23 ... Parallel data, 24 ... Clock generation circuit, 25 ... Internal clock, 2
6 ... Level comparator b, 27 ... Level comparator c, 28 ... Delay circuit, 29 ... Amplifier, 30 ... Analog-digital converter, 31 ... Exclusive OR circuit, 32 ... Detection current signal,
33 ... Data output, 50 ... Metal small piece, 51 ... Blank part, 5
2 ... Magnetic layer, 53 ... Metal vapor deposition layer, 54 ... Protective layer, 55 ...
Removed part, 56 ... Non-removed part, S ... Sensor head, 6
0, 61 ... Windings, 62, 64 ... Magnetic poles.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G06K 7/10 A 7623-5B 19/10 G11B 5/09 301 Z 7520-5D 11/03 9075- 5D // B41M 5/26 7416-2H B41M 5/26 X

Claims (9)

[Claims] 1. A medium thin film layer, an infrared absorbing layer, and a transparent protective layer are sequentially laminated on a medium substrate, and an intermediate layer recording area for recording information by melting the metal thin film layer is provided. Characteristic information recording medium. 2. The information recording medium according to claim 1, wherein information is recorded by providing a melted portion and a non-melted portion in the metal thin film layer on the medium base material, and the transparent protective layer. An information recording medium, characterized in that the metal thin film layer is selectively melted by irradiating a heat beam from the side to record information. 3. The information recording medium according to claim 1 or 2, wherein a concealing layer or a printing layer transparent to infrared rays and ultraviolet rays is provided between the metal thin film layer and the transparent protective layer. Alternatively, the information recording medium is characterized in that a visual information printing layer is provided on the surface of the transparent protective layer. 4. The information recorded on the metal thin film layer is recorded information composed of a series of regularly arranged read synchronous clock recording patterns and encoded data recording patterns. Item 1. The information recording medium according to item 1. 5. The infrared absorbing exothermic agent in the infrared absorbing layer is made of a polymethine-based material that loses its infrared absorbing and exothermic action by irradiating with light having a wavelength in the ultraviolet region above a predetermined level after irradiation with a heat beam. The information recording medium according to any one of claims 1 to 3, wherein the information recording medium is formed. 6. An information recording / reproducing apparatus for reading recorded information on an information recording medium according to any one of claims 1 to 4, wherein a predetermined gap is provided on both sides of the information recording medium. Information including at least one means for reading information by converting the magnetic field strength, which changes depending on the presence or absence of a metal film, into an electric signal, which is composed of an AC magnetic field generating coil and a pickup coil which are disposed opposite to each other. Information recording on recording media
Playback device. 7. A series of read synchronous clock recording patterns arranged regularly as information recorded in the metal thin film layer of the information recording medium according to claim 1. In an information recording / reproducing apparatus for reading recorded information composed of an encoded data recording pattern, by moving the information recording medium by a conveying means that relatively moves the information recording medium and the reading means,
An information recording / reproducing apparatus for an information recording medium, comprising means for reading recorded information with the pickup coil, converting it into a digital signal and extracting the data. 8. An information recording / reproducing apparatus for reading recorded information recorded on a metal thin film layer of the information recording medium according to claim 1, wherein: A magnetic recording area for recording magnetic information is also provided on the surface or the intermediate layer, and means for decoding the information recorded on the metal thin film layer is provided, and the information decoded by the decoding means and the magnetic recording. An information recording / reproducing apparatus for an information recording medium, characterized in that the same information recorded in an area is compared and referred to. 9. A series of regularly arranged synchronous clock recording patterns for reading as information recorded on the metal thin film layer of the information recording medium according to claim 1. In an information recording / reproducing apparatus for reading recorded information composed of an encoded data recording pattern, a recording means for recording the synchronous clock information at the time of information recording, and the information recording medium and the reading means are relatively moved. By moving the information recording medium by the transport means,
An information recording / reproducing apparatus for an information recording medium, comprising means for reading recorded information with the pickup coil, converting it into a digital signal and extracting the data.