JP2003157413A - Non-contact type ic card - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce many restrictions imposed on a built-in antenna of a non- contact type IC card. SOLUTION: In an IC card having AC voltage generating means for generating AC voltage by alternating electromagnetic field having a predetermined frequency transmitted from an external device, a converting means for converting the voltage waveform of the AC voltage to operating power and a signal component, a microprocessor that is operated by the operating power and stores and processes information thus converted, and transmitting means for converting and transmitting the signal component generated by the microprocessor, an electrostatic capacity element for adjusting a resonance frequency formed in the IC card, serving as the converting means, is equipped with a coil having inductance selected so as to resonate to the frequency shifted by a constant value with respect to the AC electromagnetic field, and connected to at least an electrostatic capacity component in the microprocessor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC card for communicating in a non-contact state, and more specifically, a non-contact type IC card having an antenna for receiving an operating power source and transmitting and receiving a signal component by an electromagnetic coupling method. Also, the present invention relates to a contact type non-contact type IC card which can be used for both contact type and non-contact type.

[0002]

2. Description of the Related Art IC cards include a memory card and a CPU
Although there is an IC card (also referred to as a smart card) on which a CPU is mounted, a CPU can be mounted on the card, and a card as an information recording medium can have high security. Further, in another classification of the IC card, when communicating with an external device, there is a contact type IC card which is connected by a terminal of an external device connecting terminal formed on the surface of the IC card and a contact of a read / write portion of the external device. , A non-contact type IC card in which an antenna is built in the IC card to communicate with an external device in a non-contact state,
There is a contact-type non-contact type IC card which can be used for both types.

Although the contact type IC card is less expensive to manufacture than the non-contact type card, the contact of an external device needs to be brought into contact with the terminal exposed on the surface of the card when communicating, so that the external type A non-contact type IC card has emerged as a substitute for it because it is necessary to provide a card insertion port in the device, and when the terminals on the card side are contaminated with oil or the like, poor contact is likely to cause troubles.

The IC card requires electric power for operating the CPU, and it is necessary to select whether to incorporate the power source into the card or receive the power from an external device. When a power source is built into an IC card, there are many necessary items such as the fact that the card is thin, visual information is displayed on the card, a magnetic recording unit is installed side by side, and an antenna is built in. When the power source is a battery, there is also a problem that the battery has a lifespan. In the case of a non-contact type IC card, necessary electric power may be generated inside the IC card by a radio wave (electromagnetic wave) supplied from an external device. Many.

The above-mentioned required power is generated in the card,
Although some methods for improving the reception characteristic have been disclosed, in recent inventions, for example, Japanese Patent Laid-Open No. 10-695.
It is introduced in Japanese Patent No. 33 as follows.

As a means for supplying electric power to the non-contact type IC card, means for incorporating a battery has been devised, but the incorporation of the battery causes problems such as thickening of the card body and battery replacement. As described above, many methods of converting received energy into electric power without mounting a battery on the card are adopted, and various coupling methods have been proposed. Among them, there are capacitive coupling method and magnetic coupling method as practical coupling methods. However, in the capacitance method using a capacitor, the energy transmission efficiency is not large, and the capacitance between the card and the reader changes, so Due to changes and low reliability of communication, the magnetic coupling method is predominant.

However, the method of improving the power transfer efficiency in the conventional example focuses only on the transmitted power, and is effective only in the effect of improving the power efficiency on the power transmitting side and sending out more power. In these methods, when the intensity of the radiated electromagnetic field is limited, it does not contribute to the improvement of the power receiving efficiency on the receiving side. In order to improve the received power of a non-contact type IC card located in a weak electromagnetic field, means for absorbing more energy radiated in the card must be provided. Further, since the IC card has a semiconductor integrated circuit built-in, obtaining more current with low power reduces the load on the power supply circuit. That is, it is desirable that the power receiving side has low impedance. However, in the conventional example, only the transmission voltage is focused on, and no reference is made to the power receiving side.

In order to solve such a problem, in a non-contact type IC card which receives electric power from the outside in a non-contact manner, a coil on the power transmitting side (reader / writer side) and a power receiving side (non-contact type IC card side) Provided is a contactless IC card which improves power efficiency on a power receiving side and performs impedance conversion in a coupler in which coils are separated by an air gap (hereinafter omitted). The invention of Japanese Patent Laid-Open No. 10-69533 has a magnetic stripe even in an IC card that has both the contact type transmission mechanism and the non-contact type transmission mechanism as described above and further has a magnetic stripe or emboss formed on the surface of the card. An object of the present invention is to provide a non-contact type IC card capable of improving the power efficiency on the power receiving side, performing impedance conversion, and forming a thin card without impairing the formation of an emboss or an emboss.

[0009]

The above-mentioned invention has the following restrictions. (1) The second coil is selected so that the capacitance element and the impedance value resonate with the electromagnetic wave from the externally provided drive unit at the frequency of the electromagnetic wave. (2) A spiral second coil is provided on the same plane as the first coil or on an adjacent plane along the outer circumference of the card while being electrically insulated from the first coil. (3) At least one turn of the second coil is formed with the same center as that of the first coil. Provided is a non-contact IC card that alleviates these restrictions.

[0010]

In order to achieve the above object, the invention of claim 1 of the non-contact type IC card of the present invention is an AC electromagnetic field of a predetermined frequency transmitted from an external device. AC voltage generation means for generating an AC voltage by means of the above, conversion means for converting the voltage waveform of the AC voltage into operating power and signal component, and a micro-processor for storing and processing information operated by the operating power and converted. In an IC card having a processor and a transmitting means for converting and transmitting a signal component generated by the microprocessor, a resonance frequency formed in the IC card as a converting means for converting the operating power and the signal component is adjusted. The capacitive element for has an inductance selected to resonate at a frequency shifted by a constant value with respect to the alternating electromagnetic field Comprises a yl, and is characterized in that it is connected to the capacitance component of at least the said microprocessor.

Further, the non-contact type I according to the invention of claim 2
The C card includes an AC voltage generating unit that generates an AC voltage by an AC electromagnetic field having a predetermined frequency transmitted from an external device, and a converting unit that converts the voltage waveform of the AC voltage into an operating power and a signal component. In an IC card having a microprocessor that operates by the operating power and stores and processes the converted information, and a transmitting unit that converts and transmits the signal component generated by the microprocessor, the IC card is an alternating current As a means for receiving an electromagnetic field, a second coil formed in the IC card and a first coil that resonates at a frequency shifted by a constant value with respect to the AC electromagnetic field are provided, and the first coil adjusts the resonance frequency. And / or a capacitive element in the microprocessor. .

The invention described in claim 3 is the same as claim 1
The invention according to any one of claims 1 to 3, wherein the metal foil is formed on at least one surface of the insulating thin plate, and the end of the first coil according to claim 2 is
It is characterized in that it is connected to the capacitance element formed on the insulating thin plate and / or a connection terminal of an IC chip mounted on the IC card.

The invention according to claim 4 is the same as claim 1.
In the invention according to any one of claims 3 to 3, the electrostatic capacitance element is formed of a pair of planar patterns formed of a conductive material, and has the same shape portion of the planar pattern with the insulating thin plate sandwiched from both sides. Are formed so as to face each other.

The invention described in claim 5 is the same as claim 4
In the invention described in (1), the capacitance element is formed by a capacitance element having a function of adjusting a capacitance value by an area of the same shape portion facing each other.

The invention described in claim 6 is the same as claim 2
The invention according to any one of claims 1 to 5 is characterized in that the first coil and the second coil are formed such that at least a part of the openings of the respective coils overlap.

The invention described in claim 7 is the same as claim 1.
In the invention according to any one of claims 1 to 6, the coil according to claim 1, the first coil according to claim 2 and the second coil have a Q value (2πfL / R) set to 15 or more. It is a feature.

The invention described in claim 8 is the same as claim 1.
In any of the above-described inventions, the insulating thin plate has a thickness of 5 to 250 μm.

The invention described in claim 9 is the same as claim 1.
In any one of Claims 8-8, the material which comprises the coil of Claim 1, the 1st coil of Claim 2, the 2nd coil, and the said capacitance element has thickness 5-5. It is for a conductive material of 50 μm.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The non-contact type IC card of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram for explaining an outline when communicating information with an external device using the non-contact type IC card of the present invention, and FIG. 2 is a diagram for explaining the invention of claim 1. 3 is a diagram for explaining the invention of claim 2, and FIG.
For explaining the invention of FIGS. 5, 6, and 7.
FIG. 8 is a diagram for explaining the invention of claims 3, 4, 5, 8 and 9, and FIG. 8 is a diagram for explaining the invention of claim 6.

In FIG. 1, a transmission / reception control unit 22 is mounted on the external device 2, and a transmission / reception coil 21 transmits a power carrier wave (electromagnetic wave) to a non-contact type IC card and transmits / receives a communication signal. The host computer 4
Information is transmitted to the external device 2. The non-contact type IC card is
Coil 51 for receiving the electromagnetic wave transmitted from the external device 2
The electrostatic capacitance element 61 that resonates with the received electromagnetic wave is mounted. In the case of the contact type non-contact type dual-purpose card, the external terminal 3 is formed on the card surface. Each independent terminal of the external terminal 3 is connected to a connection terminal of an IC chip built in the IC card by a lead wire and corresponds to a contact type external device. The terminal of the coil 51 is connected to another terminal of the IC chip. With the above-described configuration and function, the non-contact type IC card is brought closer to the external device 2 by several cm to 20 cm, and power is supplied from the external device to perform communication.

Although not illustrated, an external device of a general non-contact type IC card and a structure of the non-contact type IC card will be described here.

(Structure of External Device) First, the structure of the part that shares power transmission will be described. A power supply for generating a high frequency voltage, a coding circuit for coding an information signal for transmitting information to a non-contact type IC card, and the coded signal on a high frequency voltage generated from the power supply. A modulator for modulating with, a transmission amplifier for amplifying a signal modulated on a high frequency voltage by the modulator, and a signal amplified by the transmission amplifier is coupled by inductance coupling,
It consists of a matching circuit to prevent reflection by matching impedance with a resonant capacitor whose capacity can be changed, and a transmitting antenna that generates electromagnetic waves that transmit power and data according to the output of this matching circuit. It

(Construction of non-contact type IC card) Non-contact type I
A general configuration of the C card will be described. First, an antenna coil that receives power and data from an antenna of an external device and generates an electromagnetic wave according to transmission data, and a matching / rectification circuit that rectifies the power received by this antenna coil and matches transmission / reception signals. A power supply circuit for supplying a constant DC voltage power supply from the induced voltage rectified by the matching / rectifying circuit, a clock extracting circuit for extracting a clock from a received signal supplied from the matching / rectifying circuit, and the matching / rectifying circuit A noise removing circuit that removes noise components from the received signal supplied from the circuit, a waveform shaping circuit that shapes the received signal supplied from the LPF circuit, and a modulation circuit that modulates the transmitted signal and supplies the modulated signal to the antenna coil. There is a contact correspondence part.

Next, the frequency division circuit for dividing the frequency based on the lock signal supplied from the non-contact corresponding portion to generate a signal for operating the CPU and the signal obtained from the waveform shaping circuit of the IC chip are decoded. Then, a decoding circuit for inputting to the CPU as decoded data (reception data), an encoding circuit for encoding the transmission data obtained from the CPU and inputting it to the modulation circuit of the IC chip, and a chip configuration of an IC card for processing the received information There is a part.

The above-mentioned IC chip portion includes a central processing unit (CPU) for performing control operations by being supplied with power and signals from the interface portion, a read / write memory unit (RAM) at any time, and a read-only memory unit (ROM). , An electrically erasable read-only memory (EEPROM).

The invention of claim 1 will be described with reference to FIGS. The non-contact type IC card 1 uses the power carrier of 13.56 MHz supplied by the external device 2 and the data communication modulation wave fc210 as the coil L1 (51).
And received in parallel and connected in parallel
A resonance circuit is constructed by the above to improve the reception impedance characteristic. With the configuration of the resonance circuit, the electromagnetic wave transmitted from the external device is received as more stable power.
That is, with such a configuration, the reception impedance is reduced, and the signal can be efficiently extracted.
A clock is extracted from the received signal received by the clock extraction circuit, the noise component is removed by the matching / rectification circuit described above, and the received signal obtained from the LPF circuit is waveform-shaped by the waveform shaping circuit to generate CP.
Sent to U. The contactless contactless IC card has an external terminal 3 for receiving power and information from an external device.

The power carrier wave supplied by the external device 2 and the data communication modulated wave 210 are parallel to the capacitance element C1 (61) and the capacitance component C2 (62) formed in the CPU. The same effect can be obtained by connecting to and using together. The coil L1 and the electrostatic capacitance element C1 (61) shown in FIG. 2 are connected in parallel, and the respective ends are connected to the IC chip 30. Referring to FIG. 4, the coil L1, the capacitance elements C1, I
An example of the connection carrying of the C chip will be described. Coil L
1 has 51a and 51a on both sides of an insulating thin plate (not shown).
The end of the coil 51a and the tip of the coil 51b are connected to each other by a through hole 51ab formed in an insulating thin plate so as to face each other as shown in b. Capacitance element 6
Similarly, 1a and 61b are also formed by facing planar patterns on both sides of an insulating thin plate and are connected to the above-mentioned coil.
The capacitance element will be described in detail with reference to FIG.

The invention according to claim 2 will be described with reference to FIGS. The non-contact type IC card 1 uses the power carrier of 13.56 MHz supplied by the external device 2 and the data communication modulated wave (electromagnetic wave) 210 as an IC.
Receiving by the resonance circuit formed by the second coil L2 (52) on the card side and the electrostatic capacitance element C1 (61) connected in parallel. Furthermore, a number of parallel arranged or connected
A resonance circuit is formed by connecting one coil L1 (51) and the capacitance component C2 (62) formed in the IC chip 30 in parallel, and electromagnetic waves transmitted from an external device are converted into more stable power. To receive.

With such a configuration, the reception impedance is reduced, and electric power can be efficiently taken out.
The subsequent flow of the electric current and the signal wave is the same as that described in the description of claim 1, and therefore the description thereof is omitted. A dual-purpose IC card having both contact-type and non-contact-type functions includes an external terminal 3 for receiving power and data (information) from an external device. Each terminal of the external terminal 3 which is independent for each function and the terminal of the IC chip 30 are connected by a conductive wire.

An example of the variable capacitance type electrostatic capacitance element of the present invention will be described with reference to FIGS. 5, 6 and 7. An insulating thin plate shown in FIG. 5 (referred to as an insulating film in this section).
A metal foil (Ca, Cb) is laminated on both surfaces of P with an adhesive, and the photosensitive solution applied to the surface of the metal foil is applied with a photosensitive solution shown in FIG.
(B) pattern and coil pattern (not shown)
Is baked and unnecessary portions are removed by etching to form a capacitance element as shown in FIG. In this case, the planar patterns (Ca, Cb) formed by the metal foils formed on the front and back surfaces of the insulating plastic film are partially the same pattern, and the insulating film is fixed so as to face each other and exposed, Is etched.

As can be seen from the example of FIG. 7, the conductive planar patterns formed on both sides of the insulating film have respective ends 601a and 601b (not shown), but coil 50a as shown in FIG. , 50b connected in parallel near the end. In the planar pattern formed on the front and back surfaces of the insulating film P so that the same pattern faces each other, the connection portions A1, A2, A3 are formed in the pattern with a narrow width as shown in FIG. As described in the invention of claim 5, the power effect is optimized in FIG. 2 or 3, and the Q value of the invention of claim 7 is 15 or more. The connection portions A1, A2, A3 of are disconnected.
The power effect can be finely adjusted by using a finer pattern other than the pattern shown in FIG.
You can use it without anxiety even if you have read two of them.

Materials used for the insulating film, coil and capacitance element will be described below. In FIG. 5, as the insulating film P, a heat resistant film such as polyester or polyimide is often used. Further, the coils 50a and 50b shown in FIG.
l (aluminum), Cu (copper), Zn (zinc), Fe
An (iron) foil or an alloy foil using these elements is used. As the adhesive used for bonding the insulating film P and the metal foil, a thermosetting adhesive such as epoxy, silicone, polyimide, phenol, acrylic, or a thermoplastic and heat-sealable adhesive is used. It

The thickness of the metal foil used is from 1 to 50.
μm, preferably about 5 μm. The thickness of the insulating film is 5 to 250 μm, preferably 12 to 25 μm.
It is about μm. The reason is that for a non-contact type IC card, the coil and the capacitive element are one component that constitutes the card, and when the capacitive element laminated by the adhesive becomes thick, the total thickness of the IC card becomes large. Since the upper limit of is set, it becomes difficult to secure the overall strength of the finished card, which causes various obstacles in practical use of the card. From this point of view, since the upper limit of the thickness of the card is 840 μm, the thickness of the above-mentioned coil and the circuit board forming the capacitance element is 10
% Or less, and preferably 80 μm or less.

The Q value described in claim 7 will be described with reference to FIG. The coil L1 according to claim 1, and
In order to improve the impedance effect of the first coil L1 and the second coil L2 according to claim 2, a Q value (2πf
L / R) is set to 15 or more. The Q value of the coil is
It is a quantity that represents the power effect of the resonant circuit.
It is set by the resonance frequency f, the inductance L of the coil forming the opening, and the DC resistance component R of the resonance circuit.
The amount of the electric power carrier wave that the non-contact type IC card receives from the external device depends on the transmission coil unit (21 in FIG. 1) of the external device on the transmitting side and the receiving coil of the non-contact type IC card 1 on the receiving side. It depends on the distance from the two coils L2 (52), the angle at which they face each other, and the like. Proximity type IC with a communication distance of 20 cm between the external device 2 and the non-contact type IC card 1
In the case of a card, the non-contact type IC card 1 needs to secure the minimum required voltage 3.3V at the farthest position, for example. By setting the Q value to a slightly higher standard value 15 of 5 to 20 which is usually required, a ratio between the energy stored in the resonance circuit and the power consumed in the resonance circuit is set, which will be described later. Set the conditions of the capacitance element.

[0035]

The present invention has solved the following problems and brought about the effects. (1) A reader / writer (external device) provided outside,
Stable communication became possible without depending on the distance between IC cards. (2) It is possible to perform stable communication even when two non-contact type IC cards are stacked and used, or even when two or more cards are present in the communication space. (3) In terms of the size and arrangement of the first coil and the second coil, it suffices that any one of the coils be included in the other coil in a planar manner, so that the degree of freedom in design is expanded.

[Brief description of drawings]

FIG. 1 is a conceptual diagram for explaining an outline when communicating information with an external device using a non-contact type IC card of the present invention.

FIG. 2 is a diagram for explaining the invention of claim 1;

FIG. 3 is a diagram for explaining the invention of claim 2;

FIG. 4 is a diagram for explaining the invention of claim 3;

FIG. 5 is a diagram for explaining the invention of claims 3, 4, 5, 8 and 9.

FIG. 6 is a diagram for explaining the inventions of claims 3, 4, 5, 8 and 9.

FIG. 7 is a diagram for explaining the inventions of claims 3, 4, 5, 8 and 9.

FIG. 8 is a diagram for explaining the invention of claim 6;

[Explanation of symbols]

1 Non-contact type IC card 2 of the present invention 2 External device 3 External terminal 4 Host computer 21 Transmission / reception coil (external device side) 22 Transmission / reception control unit (external device side) 30 IC chips 50a, 50b Coils 51, 51a, 51b First coil L1 52, 52a, 52b Second coil L2 60a, 60b, 61, 61a, 61b Capacitance element C1 62 Capacitance component C2 210 Power carrier, data communication modulated wave fc 601a, 601b Connection part A1, A2 of plane pattern , A3 Cut portions Ca and Cb of planar pattern (capacitive element) One example of pattern of capacitive element P Insulating thin plate (insulating film)

Claims (9)

[Claims] 1. An AC voltage generating means for generating an AC voltage by an AC electromagnetic field having a predetermined frequency transmitted from an external device, and a converting means for converting a voltage waveform of the AC voltage into an operating power and a signal component. In the IC card having a microprocessor for storing and processing the information operated by the operating power and converted, and the transmitting unit for converting and transmitting the signal component generated by the microprocessor, the operating power and the signal The capacitance element for adjusting the resonance frequency formed in the IC card as a conversion means for converting the component into a component has an inductance selected so as to resonate at a frequency shifted by a constant value with respect to the AC electromagnetic field. And a coil having the capacitor, the coil being connected to at least a capacitance component in the microprocessor. Non-contact type IC card. 2. An AC voltage generating means for generating an AC voltage by an AC electromagnetic field having a predetermined frequency transmitted from an external device, and a converting means for converting a voltage waveform of the AC voltage into an operating power and a signal component. An IC card having a microprocessor for storing and processing the information which is operated by the operating power and converted, and a transmission means for converting and transmitting a signal component generated by the microprocessor, wherein the IC card is As a means for receiving an AC electromagnetic field, a second coil formed in the IC card and a first coil resonating at a frequency shifted by a constant value with respect to the AC electromagnetic field are provided, and the first coil adjusts a resonance frequency. Non-contact type characterized in that it is connected to a capacitance element and / or a capacitance component in a microprocessor for IC card. 3. The coil according to claim 1, wherein the metal foil is formed on at least one surface of the insulating thin plate, and the ends of the first coil according to claim 2 are formed on the insulating thin plate. A contact type IC card, which is connected to a connection terminal of an IC chip mounted on the electrostatic capacitance element and / or the IC card. 4. The capacitance element is composed of a pair of planar patterns made of a conductive material so that the same shaped portions of the planar patterns face each other with the insulating thin plate sandwiched from both sides. The contact type IC card according to claim 1, wherein the contact type IC card is formed. 5. The electrostatic capacitance element is formed by an electrostatic capacitance element having a function of adjusting the electrostatic capacitance value according to the area of the same shaped portion facing each other.
The non-contact type IC card described in any one. 6. The non-woven fabric according to claim 2, wherein the first coil and the second coil are formed such that at least a part of openings of the respective coils overlap each other. Contact type IC card. 7. The coil according to claim 1, the first coil and the second coil according to claim 2, wherein a Q value (2πfL /
R) is set to 15 or more, a non-contact type IC card. 8. The insulating thin plate has a thickness of 5 to 250 μm.
The non-contact type IC card according to any one of claims 1 to 7, wherein m is m. 9. The material forming the coil according to claim 1, the first coil and second coil according to claim 2, and the capacitance element is for a conductive material having a thickness of 5 to 50 μm. The non-contact type IC card according to claim 1, wherein