JPH1185940A - Radio communication terminal and security method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive radio communication terminal with high stability which is difficult to forge or alter. SOLUTION: An IC card 11 is provided with a circuit element 12 constituted of an integrated circuit and an antenna element 13 for communication. Those circuit elements 12 and antenna elements 13 are arranged on a supporting base material 14. The IC card 11 incorporates a magnetic element 15, and soft magnetic materials indicating the rapid reversal of magnetization when an alternating magnetic field is impressed from the outside part are included in the magnetic element 15. When the alternating magnetic field in a prescribed size is inputted as an inquiry signal from the outside part to the radio communication terminal 11, the soft magnetic body included in the magnetic element 15 indicates the rapid reversal of magnetization when an outside magnetic field strength reaches a preliminarily set level, and radiates a magnetic pulse to the outside part. This magnetic pulse is captured as a security signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication terminal and a security method therefor, and more particularly to an integrated circuit for storing data and performing arithmetic processing on the data, and an antenna for transmitting and receiving data to and from an external terminal. Non-contact IC
The present invention relates to a wireless communication terminal such as a card and a security method thereof.

[0002]

2. Description of the Related Art In recent years, so-called IC cards having built-in integrated circuits such as microcomputers and memories have been used in various fields as replacements for cards using magnetic stripes. Its application range is wide, such as transportation, finance, medical care, and services, and is used for, for example, credit cards, commuter passes, insurance cards, employee ID cards, and the like.

In particular, a non-contact IC card capable of remotely transmitting and receiving data to and from a data processing terminal device has recently been developed and is expected to be extremely convenient. These non-contact IC cards have a built-in IC for data communication and are capable of remote sensing.

FIG. 8 shows an example of a conventional IC card of this type. The IC card 1 includes a circuit element 2 composed of an integrated circuit and an antenna element 3 for communication. The circuit element 2 and the antenna element 3 are arranged on a support base 4. A circuit necessary for the circuit element 2 to function is accommodated between the support base 4 and another support base disposed below the support base 4. As the antenna element 3, a 10-turn spiral loop antenna is used. Unlike the contact type card, the IC card 1 having such a structure does not require a contact terminal electrode for electrical connection, so the card has high reliability, and a driving part such as a card transport mechanism is used. There is also an advantage that the reader / writer device is maintenance-free because there is no such device.

[0005] The antenna used for the non-contact IC card as described above is appropriately selected depending on the communication system used for the wireless communication terminal and the system for supplying power to the wireless communication terminal. Currently, the contactless IC card uses a contact type of up to about 2 mm, a close / close proximity type of up to about 1 m, and several meters of communication, depending on the distance that can be communicated with the external data processing terminal. Microwave type. The contact type is further classified into an electrostatic coupling type and an electromagnetic coupling type.

[0006] For data communication with the external data processing terminal,
A loop coil such as a spiral coil is usually used, but the size and the number of turns vary depending on the frequency used, and generally, a lower frequency has a larger number of turns. For example, currently 135 kHz (medium wave), 4.91
MHz, 13.56 MHz, 2.45 GHz (microwave) systems have already been developed. A spiral coil of about 100 turns is used for a medium wave having the lowest frequency, and a strip antenna is used for a microwave.

[0007] Many of the methods for supplying power to these non-contact IC cards also use an antenna for data transmission and reception. As this power supply method, there is a case where an electrostatic plate made of a metal plate is used as in an electrostatic coupling method.

[0008] Although not having the shape of an IC card but having the same function, there are a ski lift lift ticket and a sports club management tag. For example, a lift ticket is used in which a usage history, balance, and the like are remotely sensed by a wireless communication terminal device built in a wristband.

When money is exchanged as in the above-described example, a microcomputer having a high-performance arithmetic processing and a large memory capacity is required. But,
In recent years, a memory having a small memory capacity and a relatively simple structure has been widely used. These are called ID tags and transponders, and are mainly used for identification processing. For example,
A system for automatically recognizing and recording tags attached to athletes by radio is used at the Olympic marathon and the like. Because such systems are also highly valuable, they can be used to manage people in and out, manage livestock, sort in production and sales, etc.
In recent years, its use has been rapidly expanding.

[0010]

By the way, since these systems have been widely used, how to secure security to prevent unauthorized use is becoming a big problem. 2. Description of the Related Art Conventionally, in both a contact type IC card and a non-contact type IC card, security measures have been taken by a so-called software method by signal encryption processing. Also, tags and transponders for identification processing employ the same encryption technology as IC cards.

In a conventional system using an IC card, the contents of a program such as an encryption
There was a problem that the card was misused. Further, when such unauthorized use occurs, even if the operator of the above-described system including an IC card develops a new program to combat such unauthorized use, the unauthorized user will be required to further understand the content. The attack on the program decryption between the system operator and the unauthorized user is repeated, so that the cost of securing the system security increases. there were.

An object of the present invention is to provide a low-cost wireless communication terminal which is difficult to forge or falsify and has high security.

Another object of the present invention is to provide a security method for a wireless communication terminal capable of detecting forgery or falsification at low cost and with high reliability.

[0014]

To achieve the above object, the invention according to claim 1 stores data,
In an integrated circuit for arithmetic processing, a wireless communication terminal having a built-in antenna for transmitting and receiving data between the external terminal, including a soft magnetic material that causes a sharp magnetization reversal when an alternating magnetic field is applied from the outside, A magnetic element for outputting a magnetic pulse generated by the magnetization reversal as a security signal is provided.

The wireless communication terminal is a small portable terminal having a built-in integrated circuit comprising a CPU and a memory and an antenna, and corresponds to a so-called non-contact IC card, RF transponder, ID tag, and the like. The performance and memory capacity of the IC are appropriately selected according to the purpose of application. In the case of a sophisticated and complicated system such as money processing, an integrated circuit having a CPU having a high arithmetic processing capability and a relatively large capacity memory is used. On the other hand, an integrated circuit having a simpler CPU and a small-capacity memory can be used for identification purposes.

The above-mentioned antenna is appropriately selected according to the frequency at which data is transmitted and received. In general, a loop antenna having a larger number of windings is suitable as the frequency is lower or the data is transmitted and received more remotely. Also, when both data transmission and reception and security are performed as described later, the antenna having a large number of turns is used. Examples of the form of the antenna include a coil formed by winding a copper wire, a coil formed by etching copper or aluminum, and a coil formed by printing a silver-based conductive paint.

The magnetic element contains a soft magnetic material which exhibits a sharp magnetization reversal when an alternating magnetic field is applied from the outside. As such a soft magnetic material, for example,
A so-called large Barkhausen reversal material as disclosed in Japanese Patent No. 27958 and Japanese Patent Application Laid-Open No. 4-218905 can be used. These materials are based on Fe or C
It is an o-based amorphous or crystalline alloy, and uses the form of a thin wire, a ribbon, or a thin film. Such a material has a magnetic domain structure in which the magnetization is extremely stable in specific positive and negative directions, and when the applied magnetic field intensity reaches a certain critical value, the magnetization of all or part of the material is simultaneous. Is inverted. Although it is possible to determine strictly whether it should be a large Barkhausen inversion based on the degree of stability of the magnetic domain structure, in the present invention, strictly speaking, even if it can not be called a large Barkhausen inversion, it has similar magnetic characteristics, Any material showing a steep reversal of magnetization can be used. Further, as the magnetic element, a material used for an article monitoring marker disclosed in Japanese Patent Publication No. 3-55873 or Japanese Patent Publication No. 3-58072 can also be used.
These materials include Co-based or Ni-based amorphous alloys,
Permalloy and Sendust, bcc-Fe and fcc-Co
Of low magnetostrictive soft magnetic metal such as an alloy composed of fine crystals, and exhibits a sudden change in magnetization in a very small magnetic field due to low coercive force.

When an alternating magnetic field is externally applied to a wireless communication terminal having the above-described magnetic element, the soft magnetic material included in the magnetic element exhibits a steep magnetization reversal at a predetermined magnetic field strength, and Emit a magnetic field. Since the change in magnetization of the soft magnetic material is rapid, the emitted magnetic field is pulse-like, and a security function is obtained by detecting the magnetic pulse as a signal.

For the purpose of preventing forgery or the like, the magnetic element is
When the presence or absence of the generated magnetic pulse signal is checked and used as a security signal, the number of magnetic elements may be one. On the other hand, for example, when it is desired to identify the type or state of the wireless communication terminal, a plurality of types of signals are required.
Such identification can be realized by making the number of the magnetic elements plural.

The magnetic field strength at which the soft magnetic material included in the magnetic element exhibits a steep magnetization reversal corresponds to a large Barkhausen reversal critical magnetic field in the Fe-based amorphous metal thin wire disclosed in Japanese Patent Publication No. 3-27958. In the case of the permalloy ribbon disclosed in Japanese Patent Publication No. 3-55873, the permalloy thickness substantially corresponds to the coercive force. Therefore, if a large number of magnetic elements including a soft magnetic material having a large Barkhausen reversal critical magnetic field or a different coercive force are incorporated in a wireless communication terminal, when a periodic alternating magnetic field is applied from the outside, the external magnetic field becomes large for each of the large magnetic fields. Each magnetic element generates a magnetic pulse each time the critical magnetic field or the coercive force is reached, so that information according to the number and type of the built-in magnetic elements can be transmitted.

Further, the invention according to claim 2 is based on claim 1.
In the wireless communication terminal according to the above, the magnetic element is a current,
It is characterized in that the magnetic properties are changed by application of any one of voltage, magnetic field, stress and cutting.

As the soft magnetic material included in the above magnetic element which shows a steep magnetization reversal when an alternating magnetic field is applied from the outside,
For example, an Fe-based or Co-based amorphous metal thin wire exhibiting the above-described large Barkhausen inversion characteristic can be used. It is known that the magnetic properties of such an amorphous metal thin wire are changed by heating, and a large Barkhausen inversion property can be eliminated or developed by heat treatment. In particular, when a magnetic field or stress is superimposed, the above effect is further emphasized. When a current is passed through the magnetic element, not only can the magnetic element be heated by Joule heat, but also a magnetic field is generated by the current. Therefore, the magnetic element is heated in the magnetic field, and the large Barkhausen inversion characteristic can be eliminated.

On the other hand, soft magnetic materials are generally sensitive to stress. In particular, materials having large magnetostriction tend to have a strong tendency. However, even for zero magnetostrictive materials, the influence of stress cannot be ignored.
Therefore, by applying or removing a stress to the magnetic element, its magnetic characteristics can be changed. As for the method of applying stress, an elastic body is used as a holding member for the soft magnetic material, embossing is applied from above the magnetic element to apply stress, and a resin or metal that is thermally, electrically or optically deformed is adhered to the soft magnetic material. There is a method such as arrangement. Also, when a soft magnetic material is cut, its magnetic properties naturally change. Therefore, the characteristics of the magnetic element can be changed by punching a hole in the magnetic element.

According to a third aspect of the present invention, in the wireless communication terminal according to the second aspect, the soft magnetic material of the magnetic element is a metal-based magnetic material and constitutes a part of an electrode of a capacitor. In addition, the capacitor is characterized by the dielectric breakdown of the capacitor due to the conduction or the irradiation of radio waves, and the characteristics of the metallic soft magnetic material are changed.

A metallic magnetic material is used as the soft magnetic material included in the magnetic element, and this material is used for part or all of the electrodes to form a capacitor. This capacitor is made to have a structure with a low withstand voltage, and when it is directly energized or irradiated with strong radio waves, the insulation is broken and short-circuited, and the capacitor is destroyed. At this time, the soft magnetic material, which is also the electrode of the capacitor, is altered or physically destroyed by the arc generated at the time of insulation breakdown,
Magnetic properties change. Therefore, since a signal different from that before the processing is generated from the wireless communication terminal that has performed such processing, the information has been changed. In this way, information that has been changed once will not be restored again, but will help prevent unauthorized modification of the security signal.

According to a fourth aspect of the present invention, in the wireless communication terminal according to the second aspect, a hard magnetic material having a coercive force greater than that of the soft magnetic material is provided near the magnetic element. And a magnetic bias element for applying a bias magnetic field to the soft magnetic material by magnetizing the hard magnetic material to change its magnetic characteristics.

When the hard magnetic material is magnetized, a bias magnetic field is applied to the soft magnetic material of the magnetic element by the residual magnetization to change the magnetic characteristics of the soft magnetic material. In order to change the magnetic characteristics by the bias magnetic field, for example, a plurality of magnetic bias elements including a hard magnetic material may be arranged in the longitudinal direction of the soft magnetic material, and the bias magnetic field may be applied from a large number of magnetic poles. In this way, sharp magnetization reversal of the soft magnetic material is suppressed. Therefore, the magnetic element is prevented from generating a magnetic pulse by the magnetic bias element in which the hard magnetic material is magnetized. When a hard magnetic material is disposed over the entire soft magnetic material or a magnetic bias element is disposed at both ends in the longitudinal direction of a magnetic element including a soft magnetic material, a relatively uniform magnetic field is applied to the magnetic element. Is done. In this case, the soft magnetic material of the magnetic element generates a steep magnetization reversal, but its magnetic field strength is shifted by the amount of the bias magnetic field from the magnetic bias element. Therefore, the generation timing of the magnetic pulse changes. Further, as disclosed in Japanese Patent Application No. 7-340291, hard magnetic materials are arranged at both ends of a soft magnetic material, and a sharp magnetization reversal is caused only when these hard magnetic materials are magnetized. Can also. In this case, both the steepness and the generation timing of the magnetic pulse signal are changed by the magnetization process of the hard magnetic material. If the magnetic properties of the soft magnetic material are changed by applying a magnetic field, the magnetization process can be performed without contact, and the information to be recorded can be rewritten again.

According to a fifth aspect of the present invention, an alternating magnetic field is externally applied to a wireless communication terminal having a built-in integrated circuit, an antenna, and a magnetic element to cause the magnetic element to perform a steep magnetization reversal. A security is obtained by emitting a pulse and detecting and processing the emitted magnetic pulse.

An alternating magnetic field is externally applied to the wireless communication terminal. This magnetic field has the function of an interrogation signal.
The frequency may be appropriately selected according to the magnetic material used, but is generally several Hz to several hundred kHz. The data transmission / reception frequency of the wireless communication terminal may be used as it is, or may be superimposed using a different frequency. At this time, the frequency for transmitting and receiving data and the frequency for interrogating the magnetic element are separated from each other in band. When the magnetic element is in a state capable of sharply reversing the magnetization when asked by the alternating magnetic field in this way, a magnetic pulse is generated according to the strength of the reversing magnetic field. The magnetic pulse is detected by a detection antenna having a loop shape or the like, and the intensity, waveform, phase, frequency distribution, and the like of the voltage generated in the antenna are appropriately analyzed, and the security signal is read. In the simplest case, only the presence or absence of a magnetic pulse is examined.
The antenna that detects the magnetic pulse may be located close to or completely separate from the magnetic field generating antenna to be interrogated.However, when analyzing the phase relationship with the interrogating magnetic field, Are arranged in a way.

According to a sixth aspect of the present invention, in the wireless communication terminal security method according to the fifth aspect, a magnetic pulse radiated by the magnetic element is detected by the antenna provided in the wireless communication terminal itself. A corresponding security signal is radiated from the antenna to the outside.

The magnetic pulse generated by the magnetic element can be detected by a coil built in the wireless communication terminal. However, in a very small magnetic element, since the intensity of the generated magnetic pulse is small, it is difficult to detect the signal at a long distance. Therefore, if the detection is performed by the wireless communication terminal itself, the detection can be performed with the highest sensitivity. In the case of a wireless communication terminal transmitting and receiving at a frequency below the MHz band, it is possible to use the antenna coil for data transmission and reception as it is for this detection antenna. However, magnetic pulse detection is performed separately from the antenna for data transmission and reception. May be provided with a dedicated antenna coil. The signal of the magnetic pulse detected by the antenna of the wireless communication terminal is transmitted from the data transmitting / receiving antenna to the external terminal. in this case,
The detected magnetic pulse signal may be sent as it is, or the pulse signal may be analyzed by a wireless communication terminal to some extent, converted into a signal corresponding to the signal, and then transmitted.

[0032]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) FIG. 1 shows a first embodiment of a wireless communication terminal according to the present invention. The wireless communication terminal is I
A C card, wherein the IC card 11 includes a circuit element 12 formed of an integrated circuit and a communication antenna element 13;
The circuit element 12 and the antenna element 13 are
4. Circuits necessary for the circuit element 12 to function are accommodated between the support base 14 and another support base (not shown) disposed below the support base 14. The antenna element 3 is a 10-turn spiral loop antenna.

The radio communication terminal 11 has a built-in magnetic element 15, and the magnetic element 15 contains a soft magnetic material that shows a sharp magnetization reversal when an alternating magnetic field is applied from the outside. When an alternating magnetic field of a predetermined magnitude is input as an interrogation signal to the IC card 11 from the outside, the soft magnetic material included in the magnetic element 15 sharply magnetizes when the external magnetic field intensity reaches a predetermined level. A magnetic pulse is emitted to the outside indicating inversion. This magnetic pulse is captured as a security signal. In FIG. 1, the magnetic element 15 is arranged on the antenna element 13, but may be located anywhere on the wireless communication terminal 11.

(Second Embodiment) FIG. 2 shows a second embodiment of the wireless communication terminal according to the present invention. This IC card 11
A shows an IC card 11 of FIG. 1 in which three magnetic elements 15A, 15B, and 15C are used instead of the magnetic element 15. These magnetic elements 15A, 15B, 15C
Are emitted by magnetic pulse signals at different magnetic field strength levels. Specifically, each magnetic element 1
5A, 15B, and 15C include soft magnetic materials having different magnetization reversal magnetic fields. Thus, the plurality of magnetic elements 15A,
By using 15B and 15C, it is possible to give distinctiveness to each wireless communication terminal. FIG. 2 shows an example in which three magnetic elements 15A, 15B, and 15C are used,
The number is not particularly limited, and the installation place does not necessarily have to be arranged at the same place as shown in FIG.

The magnetic element 15 and the magnetic elements 15A, 1
5B and 15C transmit the magnetic pulse signals to the wireless communication terminal 1
1 and the antenna element 13 of the wireless communication terminal 11A, it is desirable that the antenna element 13 is disposed as close to the antenna element 13 as possible, preferably on the antenna element 13. Therefore, the structure of FIG. 1 and FIG.
This embodiment shows a preferred embodiment as a wireless communication terminal capable of detecting a security signal by the antenna 1 of the IC card 11A or the antenna 13 of the IC card 11A and having high sensitivity detection performance.

(Third Embodiment) FIG. 3 shows a third embodiment of the wireless communication terminal according to the present invention. The IC card 11B has a second antenna element 16, and the magnetic element 15 is arranged on the antenna element 16. Since the second antenna element 16 is arranged on the IC card 11B exclusively for detecting the magnetic pulse signal of the magnetic element 15 and is specially adjusted for that purpose, as shown in FIG. 1 or FIG. 13 is higher in sensitivity than when 13 is used in combination.

[0038]

The present invention will be described below in detail with reference to examples and comparative examples. The wireless communication terminal according to the present invention includes the magnetic element 15 and the magnetic elements 15A and 15
B and 15C are built in, and can be in a card form, a chip form, or other forms, and a number of manufacturing methods can be considered along with them. Therefore, the present invention is not limited to the examples described later. The following examples are provided for the purpose of deepening the understanding of the present invention, and assume a non-contact IC card which is one of the embodiments of the wireless communication terminal of the present invention. That is, an embodiment in which a magnetic element is built in a plastic base will be described below.

(Example 1) A wire diameter of 30 μmφ and a length of 50 m
m ₃₉ Co ₃₉ Fe ₃₉ Si ₇ B ₁₅ (atomic%) amorphous metal fine wire is sandwiched between two 25 μm-thick PET films coated with an adhesive, and then fixed, and a 100 μm-thick PE
A card-shaped sample was obtained by performing a pouch process by sandwiching the two T films. This sample was inserted into the center of an excitation coil having a length of 300 mm and 560 turns and a detection coil (with a compensation coil) having a length of 100 mm and 640 turns. The excitation coil is a Hewlett-Packard HP
AC current is supplied from a −3324A synthesized function sweep generator,
A sinusoidal magnetic field of 1 Oe was generated. Hewlett-Packard HP-54 detection coil
A 110 digitizing oscilloscope was connected, and the voltage waveform induced in the detection coil by the magnetization reversal of the sample was measured.

FIG. 4 shows a waveform of a voltage pulse generated in the detection coil. Since the magnetization reversal of the amorphous metal thin wire is extremely steep, a sharp pulse waveform having a small half-value width was observed, and a security function such as confirmation of card validity could be obtained by the presence or absence of this waveform. The identification of the magnetic pulse signal could be performed not only by checking the waveform but also by analyzing the frequency distribution and measuring a specific harmonic component.

(Embodiment 2) In addition to the structure of Embodiment 1, three pieces of a semi-hard magnetic material having a larger coercive force than the above-described fine metal wire (Arnochrome manufactured by Arnold) are arranged on the fine metal wire. A card-shaped sample was prepared. A DC magnetic field of about 100 Oersted was applied to the sample, and these magnetic sections were magnetized. The characteristics of the sample thus obtained were measured in the same manner as in Example 1. FIG. 5 shows a waveform of a voltage generated in the detection coil. The waveform clearly changes as compared with FIG. 4, and it can be seen that the magnetic pulse signal is no longer emitted. Thus, the magnetic pulse signal could be controlled by applying the bias magnetic field from the semi-hard magnetic section to the soft magnetic material made of the amorphous metal thin wire.

Example 3 Five types of fine wires having different magnetic fields for reversing the magnetization were produced by changing the heat treatment conditions of Co ₃₉ Fe ₃₉ Si ₇ B ₁₅ (atomic%) amorphous metal fine wires. The switching field was 0.7, 1.1, 1.7, 2.2, and 3.4 Oersteds in ascending order. Make these thin lines 1
A card-shaped sample was prepared by arranging 5 pieces in parallel with 5 mm. This sample was placed in the center of an exciting coil having a length of 300 mm and a number of turns of 560 and a detection coil having a length of 15 mm and a number of turns of 527 (with a compensating coil) so that the longitudinal direction of the coil and the longitudinal direction of the fine wire coincided. Inserted. As in Example 1, a 60 Hz, 4 Oe triangular wave magnetic field was generated in the excitation coil, and the voltage waveform induced in the detection coil by the magnetization reversal of the sample was measured.

FIG. 6A shows a voltage waveform of this sample. In addition, each voltage pulse and the thin line which generated it could be collated by the time position which clocks the signal (60 Hz) of an excitation magnetic field. Further, FIG.
(E) shows a voltage waveform when different thin lines are divided one by one. It can be seen that the signal is no longer emitted at the locations marked with a cross in the figure due to the division processing. That is, it was possible to identify which thin line was processed by monitoring the voltage waveform.

It has been clarified that when a plurality of different types of thin wires are used, a plurality of types of signals can be handled in accordance with the combination, and more signals can be used when a method of changing the signal is used in combination. .

Example 4 First, a polyethylene terephthalate (PET) film (125 μm thick) was coated with a water-soluble ink (manufactured by Osaka Printing Ink Co., Ltd.) containing spherical silicon oxide and calcium carbonate as pigments at a thickness of 17 μm.
Screen printing was performed so that At this time, the short side 10
mm, long side 60mm, short side 1mm, long side 50mm
The ink was applied in a lattice-frame-like pattern in which four openings were arranged. Next, using a DC magnetron sputtering apparatus disclosed in Japanese Patent Application Laid-Open No. 4-218905, an amorphous thin film having a thickness of 0.5 μm and having a composition of Co ₅₁ Fe ₂₆ Si ₁₀ B ₁₃ (the number represents atomic%) is formed. , On a screen printed PET film. The film was washed with water to remove the water-soluble ink and the thin film deposited thereon, thereby obtaining a sample in which four elongated strip-shaped thin films having a short side of 1 mm and a long side of 50 mm were arranged.

The card-like sample containing an elongated thin film obtained in this manner was applied to an AC BH tracer (AC, BH-100).
K, detection coil width 10 mm, manufactured by RIKEN ELECTRONICS CO., LTD.), Triangular wave excitation is applied, and the voltage waveform induced in the detection coil is X
Recorded on Y plotter. Excitation is 20Hz, 0.5O
e.

FIG. 7 (a) shows the voltage waveform of the detection coil obtained in this manner, and a magnetic pulse signal similar to the signal obtained by the thin metal wire in Examples 1 to 3 is obtained by a thin film material. It became clear that it could be used for security. FIGS. 7B to 7E show voltage waveforms when the strip-shaped thin films are divided one by one. As in the case of the thin wire of the third embodiment, the emission of the magnetic pulse signal was suppressed even by the dividing process even in the thin film. Thus, the security signal can be identified by monitoring the voltage waveform.

[0048]

According to the present invention, when an alternating magnetic field is applied from the outside, the soft magnetic material of the magnetic element exhibits a steep magnetization reversal at a predetermined magnetic field intensity and emits a magnetic pulse to the surroundings. By detecting the magnetic pulse as a security signal, forgery or falsification of the wireless communication terminal can be detected, and a low-cost wireless communication terminal that is difficult to forge or falsify and has high security can be obtained.

When any one of current, voltage, magnetic field, stress, and cutting is applied, the magnetic properties of the magnetic element change. By applying these physical quantities, the large Barkhausen inversion property can be eliminated or developed. The characteristics of the magnetic element can be changed, whereby various security signals can be generated, and a highly reliable wireless communication terminal that is more difficult to forge or falsify can be obtained.

Further, if the magnetic element constitutes a part of the electrode of the capacitor, the soft magnetic material of the magnetic element is broken down by energization or irradiation of radio waves, and the arc generated at that time causes the softening of the magnetic element. The magnetic material is altered or physically destroyed, and the magnetic characteristics change, and a signal different from that before processing is generated from the wireless communication terminal that has been subjected to such processing, and the information previously held by the magnetic element is lost. Changed,
Unauthorized alteration of the security signal can be prevented.

Furthermore, if the magnetic characteristics are changed by applying a bias magnetic field to the soft magnetic material of the magnetic element by magnetizing the magnetic bias element, both the steepness of the magnetic pulse signal and the generation timing are improved. Because of the change, not only can the processing be performed without contact, but also the security information to be recorded can be rewritten again.

Further, when questioned by the alternating magnetic field, the magnetic element undergoes rapid magnetization reversal, and a magnetic pulse is generated in accordance with the strength of the reversing magnetic field. The magnetic pulse is detected by a loop-shaped detecting antenna. The security signal can be read easily and with high reliability based on the intensity, waveform, phase, frequency distribution, etc. of the voltage generated in the antenna.

Furthermore, if a magnetic pulse radiated by the magnetic element is detected by an antenna coil provided in the wireless communication terminal itself, and a security signal corresponding to the detected magnetic pulse is radiated from the antenna to the outside, a very small size can be achieved. Even if the intensity of the magnetic pulse generated by the magnetic element is small, the signal can be detected even at a long distance.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a first embodiment of a wireless communication terminal according to the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a second embodiment of the wireless communication terminal according to the present invention.

FIG. 3 is an explanatory diagram illustrating a configuration of a wireless communication terminal according to a third embodiment of the present invention.

FIG. 4 is a measurement waveform diagram of a magnetic pulse detected by a detection coil in the first embodiment.

FIG. 5 is a measurement waveform chart of a voltage generated in a detection coil in the second embodiment.

FIG. 6 is a measurement waveform chart of a magnetic pulse detected by a detection coil in the third embodiment.

FIG. 7 is a measurement waveform diagram of a magnetic pulse detected by a detection coil in a fourth embodiment.

FIG. 8 is an explanatory diagram showing a configuration of a conventional wireless communication terminal.

[Explanation of symbols]

 Reference Signs List 11 IC card (wireless communication terminal) 11A IC card (wireless communication terminal) 11B IC card (wireless communication terminal) 12 integrated circuit 13 antenna element 14 support base material 15 magnetic element 15A magnetic element 15B magnetic element 15C magnetic element 16 antenna element

Claims (6)

[Claims] A wireless communication terminal having a built-in antenna for transmitting and receiving data between an integrated circuit for storing and performing arithmetic processing on data and an external terminal, wherein a steep magnetization is generated when an external magnetic field is applied from the outside. A wireless communication terminal comprising: a magnetic element that includes a soft magnetic material that causes reversal and outputs a magnetic pulse generated by the magnetization reversal as a security signal. 2. The wireless communication terminal according to claim 1, wherein the magnetic characteristics of the magnetic element change when any one of a current, a voltage, a magnetic field, a stress, and a cut is applied. 3. The wireless communication terminal according to claim 2, wherein the soft magnetic material of the magnetic element is a metallic magnetic material and constitutes a part of an electrode of the capacitor, and the soft magnetic material is energized or irradiated with radio waves. A radio communication terminal characterized in that the dielectric breakdown of a capacitor and a change in the characteristics of the metal-based soft magnetic material occur. 4. The wireless communication terminal according to claim 2, further comprising a hard magnetic material disposed near said magnetic element and having a coercive force greater than said soft magnetic material, and magnetizing said hard magnetic material. A wireless communication terminal comprising a magnetic bias element for applying a bias magnetic field to the soft magnetic material to change its magnetic characteristics. 5. An alternating magnetic field is externally applied to a wireless communication terminal having a built-in integrated circuit, an antenna, and a magnetic element to cause the magnetic element to perform a sharp magnetization reversal and emit a magnetic pulse. A security method for a wireless communication terminal, wherein security is obtained by detecting and processing a pulse. 6. The security method for a wireless communication terminal according to claim 5, wherein the magnetic element emits a magnetic pulse.
A security method for a wireless communication terminal, wherein the security signal is detected by the antenna provided in the wireless communication terminal itself, and a security signal corresponding to the detection is radiated from the antenna to the outside.