JP2000105809A - Manufacture of noncontact ic card and its antenna pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a long communication range and to enable manufacturing at low cost by forming the antenna pattern of conductive paste on the top surface of a resinoid film substrate with specific resistivity. SOLUTION: The noncontact IC card 2 is put close to an R/W unit 1 and then electric power is transmitted by radio between the R/W unit 1 and noncontact IC card 2 to further transmit and receive information by radio. Namely, an electric power wave or communication wave is radiated by a coil or spiral antenna 101 for the reader writer and this electromagnetic wave is received by a coil or spiral antenna 201 on the card side to place a card-side circuit in operation, thereby to detect signals. In this case, the ratio of the DC voltage power source 205 supplied from a power circuit to the electric power supplied to the card antenna 201 is preferably >=60% and, in concrete, the resistance of the card antenna 201 is preferably <=10 Ω.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact type IC card in which a semiconductor integrated circuit or the like is incorporated in a thin case and which transmits and receives information signals to and from external devices using electromagnetic waves. The present invention relates to a structure of an antenna pattern of a contact IC card and a method of manufacturing the same.

[0002]

2. Description of the Related Art IC cards are considered to be used in a wide range of fields. Among them, in particular, the driving of a circuit which does not have a built-in power supply such as a battery but is contactless and is built in by an external electromagnetic wave. The non-contact type IC card to which power is supplied is expected to be used in various fields in the future, such as a commuter pass or a ticket used when entering or exiting a ticket gate of a station or getting on or off a bus. In such a non-contact IC card of an external power supply type, when passing or approaching the reader / writer in a non-contact manner, power is supplied wirelessly from the reader / writer and a predetermined information signal is transmitted. It transmits and receives.

In such a non-contact type IC card of an external power supply type, an antenna for supplying power and transmitting / receiving information signals is usually provided with (1) a conductor foil attached on an insulating film. Is formed by etching into a predetermined shape (spiral), (2) is formed by a conductive wire having a circular or rectangular or elliptical cross section, and (3) a conductive paste is printed on an insulating film by printing. Those formed are known. In particular, in an IC card, an IC card in which a conductive paste is formed into a spiral coil pattern by a silk screen printing method and a method of manufacturing the same are already known, for example, from Japanese Patent Application Laid-Open No. 9-1970.

[0004]

In the above prior art,
For an antenna formed by etching or conducting wires, the resistance of the antenna can be reduced by selecting a conductor material having a low resistivity. However, an antenna formed by silk-screen printing of a conductive paste cannot always ensure a sufficient communication distance (a distance from a reader / writer in which an IC card can operate).

[0005] However, if the communication distance is limited to a short distance, the original advantage of the non-contact type IC card is lost, and the output of electromagnetic waves may be increased. Due to laws and regulations, there is a limit in increasing the electromagnetic wave output from the reader / writer. Therefore, in a non-contact type IC card (especially when the communication distance is long), an antenna formed by silk screen printing or the like, which has a high resistance of the formed antenna and causes a large power loss, should be used. Was difficult.

On the other hand, in a method of manufacturing an antenna of a non-contact type IC card by etching copper, aluminum, or the like, the antenna can be made thin and
In addition, by selecting a conductor material having a low resistivity as the antenna conductor, the resistance of the antenna itself can be reduced. However, in this etching method,
As compared with other manufacturing methods, the number of steps is large and complicated, and therefore, the manufacturing cost of the IC card is increased.

Further, in the method using a conductor for the antenna, an IC card can be manufactured relatively inexpensively, and the conductor for the antenna itself can be made of a material having a low resistivity as its conductor, thereby reducing the resistance of the antenna. IC card with low cost can be realized. However, in the method using such a lead wire, there is a limit to a reduction in the thickness of an IC card.
The work of connecting the antenna of the conductor and the built-in IC circuit becomes complicated, and it is difficult to automate the production and mass-produce it.

On the other hand, when the antenna is manufactured by printing as described above, the antenna can be manufactured at low cost, and
Since the thickness of the formed antenna can be reduced, the method of forming the antenna by printing the conductive paste is suitable for a thin IC card which is produced and consumed in large quantities.

However, as described above, generally,
The resistivity of the conductor paste is about 10 times larger than that of a metal foil such as copper or aluminum, or a conductor, so that the resistance of the antenna itself is increased and the communication distance is shortened. Therefore, in order to reduce the resistance of the antenna in order to increase the communication distance, the line width of the spiral antenna pattern formed by printing is increased or the thickness thereof is increased to cut the antenna conductor. The area must be increased. However, if the thickness of the antenna pattern is increased by printing, so-called "wandering" and "smearing" occur in manufacturing problems, and the amount of conductive paste used increases. The advantages of a method of manufacturing an antenna coil by printing a certain conductive paste are lost.

In addition, as described above, particularly when the antenna coil of the IC card is formed in a spiral shape, if the antenna has the same outer dimensions and the line width of the antenna pattern is increased, the number of turns is reduced. Must be
This reduces the required inductance,
There is a problem that large power cannot be received.

That is, the present invention solves the above-mentioned problems, particularly the above-described problem in the antenna pattern of the non-contact type IC card of an external power supply type supplied with power from the outside. It is an object of the present invention to provide a non-contact type IC card which has a long communication distance and can be manufactured at low cost, and a method for manufacturing an antenna pattern thereof.

[0012]

By the way, according to the present invention, there is provided a non-contact type external power supply type IC card which transmits and receives information while being supplied with power from a reader / writer without incorporating a power supply therein. In order to efficiently receive the electric power supplied by the electromagnetic wave, the formed antenna coil needs to have a large inductance and a small resistance value.

However, as described above, when printing of a conductive paste is adopted as a method of manufacturing such an antenna pattern, a sufficient communication distance cannot always be obtained. According to the study by the present inventors,
This is because the antenna conductor formed by this printing has a resin and a void for bonding, in addition to the metal particles having conductivity, so that the antenna conductor has higher resistance than other methods. Furthermore, when the resistance of the antenna coil increases, the power consumed by the antenna itself increases, and the proportion of the power that can be supplied to the IC for processing the signal decreases rapidly. If the resistance of the reader / writer is large, it is necessary to shorten the communication distance between the reader / writer and the card, or to transmit power (electromagnetic waves) from the reader / writer in order to obtain enough power to drive the IC. It was confirmed that it was necessary to increase.

Therefore, the present invention has been made based on the above findings of the present inventors. Specifically, the present invention employs conductive paste printing as a method of manufacturing an antenna pattern, while maintaining a sufficient communication distance. It is possible to secure,
Accordingly, an inexpensive manufacturing method using a conductive paste printing method provides an external power supply type non-contact type IC card and a method for manufacturing its antenna pattern.

That is, specifically, according to the present invention,
In order to achieve the object of the present invention, first, a semiconductor integrated circuit and a resin film substrate are sealed inside a plate-like housing of a predetermined size, and a resin sealed inside the plate-like housing. An antenna pattern is formed on at least one surface of the film-making substrate, so that non-contact capable of receiving external power by electromagnetic waves and transmitting and receiving information signals from the outside via the antenna pattern. In the type IC card, the antenna pattern formed on the surface of the resin film substrate is formed using a conductive paste at a resistivity of 10 μΩcm or less.
A C card is provided.

Further, according to the present invention, in order to achieve the above object, a semiconductor integrated circuit and a resin film substrate are sealed inside a plate-like casing having a predetermined size, and the plate-like casing is sealed. An antenna pattern is formed on at least one surface of the resin-made film substrate sealed inside the body, whereby an external power signal is received via the antenna pattern and an external information signal is received. In the non-contact IC card capable of transmitting and receiving, the antenna pattern formed on the surface of the resin film substrate is formed using a conductive paste,
Further, the antenna pattern formed using the conductive paste is such that the power supplied to the semiconductor integrated circuit with respect to the total power supplied from the outside by the electromagnetic wave is 6%.
A non-contact IC card set to have a resistance value of 0% or more is provided.

According to the present invention, in the above-mentioned non-contact type IC card, the resistance value of the antenna pattern is 10Ω or less.

According to the present invention, in the non-contact type IC card described above, the antenna pattern formed on the surface of the resin film substrate is formed in a spiral shape.

Further, according to the present invention, there is provided a method for manufacturing an antenna pattern in a non-contact type IC card as described above, wherein a conductive paste is formed on at least one surface of the resin film substrate by screen printing. There has been proposed a method of manufacturing an antenna pattern in which the antenna pattern is formed by pressing or under heating.

In addition, according to the present invention, there is provided the above-described method for manufacturing an antenna pattern, wherein the pressing is performed at a pressure of 320 kg / cm ² or more.

[0021]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. First, a non-contact type I of an external power supply type according to an embodiment of the present invention is described.
A C card (hereinafter, in some cases, referred to as a wireless IC card in this embodiment), a reader and / or a wireless IC card which wirelessly supplies power to the wireless IC card and transmits / receives signals.
Alternatively, a writer (hereinafter simply referred to as an R / W unit) will be briefly described.

First, FIG. 5 shows a schematic configuration of a system for transmitting and receiving information such as a ticket or a commuter pass as a wireless IC card by wireless. That is, in the embodiment shown in FIG.
Power transmission between a / W coil (coil or spiral R / W antenna) 101 and a card coil (coil or spiral card antenna) 201 formed on an IC card (proximity wireless card) 2 Both power transmission and communication transmission / reception are performed using electromagnetic waves (radio waves) composed of waves and data communication modulated waves. According to the present embodiment, in order to simplify the non-contact type card (that is, the proximity type wireless card) 2, the electric field strength is limited to within the radio law (500 μV / m at a distance of 3 m), and , A single antenna (R / W coil) 101
To transmit this modulated wave.

That is, the R / W unit 1 has 13.56.
A power supply 105 for generating a high-frequency voltage of MHz, and input transmission data (DAT) to be transmitted to the proximity wireless card 2.
A) an encoding circuit 107 for encoding 106; amplitude modulation (Amplitude Shift Keying modulation) by a signal encoded by the encoding circuit 107 on a high frequency voltage of 13.56 MHz generated from the power supply 105; A modulator 108 for superimposing; a transmission amplifier 109 for amplifying a signal ASK-modulated on a high frequency voltage of 13.56 MHz by the modulator 108; a signal amplified by the transmission amplifier 109 is coupled by an inductance coupling 103 And capacitor 1
A matching circuit (feeding circuit) 102 for matching impedance to prevent reflection by providing an electromagnetic wave 04 to generate electromagnetic waves for power transmission and data transmission according to the output of the matching circuit 102; An R / W coil 101 for receiving data transmitted by an electromagnetic wave from a card coil 201 of the wireless card 2;
01: a filter circuit 110 for matching the signal received at 01 with a matching circuit 102 and removing a noise component from the signal generated by the inductance coupling 103;
Receiver amplifier 111 for amplifying a signal obtained through zero
And the signal amplified by the receiving amplifier 111
Demodulator 112 that demodulates using a 13.56 MHz high frequency voltage signal obtained from
2 to decode the demodulated signal and receive data (DAT
A) A decoding circuit 113 for outputting the data as 114.

On the other hand, the proximity wireless card (contactless card) 2 includes a card coil 201 and a semiconductor IC.
A wireless chip 202 as a chip; also a semiconductor IC
And a CPU + interface chip 210 which is a chip. Note that by reducing the size of the wireless chip 202, the wireless chip 202 and the CPU + interface chip 210 can be configured as one chip. The card coil 201 receives an electromagnetic wave generated for transmitting power and transmitting data from the R / W coil 101 of the R / W unit 1 and generates an electromagnetic wave corresponding to the load-switched modulated transmission data. Is what you do.

The wireless chip 202 rectifies the 13.56 MHz power received by the card coil 201 and matches the impedance of the transmitted / received signal with a matching / rectifying circuit 203 for matching;
5 from the induced voltage rectified from the matching / rectifying circuit 203
a constant voltage power supply circuit 204 for supplying a constant DC voltage power supply 205 of about 2 to 5 V at about mW; a clock extraction circuit 206 for extracting a clock from a received signal obtained from the card coil 201; An LPF circuit 207 for removing a noise component from the received signal; a waveform shaping circuit 208 for shaping the waveform of the received signal obtained from the LPF circuit 207; And a load switching modulation circuit 209 for supplying the load switching modulation circuit 209 to the card coil 201.

Here, the CPU + interface chip 210 is the clock extraction circuit 2 of the wireless chip 202.
A frequency dividing circuit 211 for generating a signal for operating the microcomputer 214 by dividing the frequency based on the clock signal extracted in 06;
A decoding circuit 212 for decoding a signal obtained from the waveform shaping circuit 208 of the wireless chip 202;
A received data control circuit 213 for controlling the decoded data (received data) obtained from the microcomputer 2 and inputting it to the microcomputer 214; a transmission data control circuit 215 for controlling the transmitted data from the microcomputer 214; The transmission data obtained by the control is encoded and the wireless chip 2
A microcomputer 214 such as an H8 which incorporates a memory for storing information as a card and performs processing of transmission / reception data and transfer of data to / from the memory; And is configured to receive a stable power supply 205 from the constant voltage power supply circuit 204 of the wireless chip 202.

The reason why the R / W coil 101 and the card coil 201 are used to transmit electric power by electromagnetic waves (wireless) is to improve the efficiency of electric power transmission in the vicinity. Further, when the coil 201 is formed on the close proximity wireless transfer card 2, there is an advantage that the close proximity wireless transfer card 2 is resistant to deformation. Further, the R / W coil 101 may be formed by a spiral antenna, like the card coil 201.

Even if the distance between the IC card 2 and the R / W unit 1 is remarkably large, the internal circuits 210 and
The card coil 201 is provided with a resonance circuit so as to connect the tuning capacitor 25 and obtain a large induced power so that a desired DC voltage can be supplied to the card coil 202. As the card coil 201, a spiral antenna coil is continuously wound in the same direction.
With a multilayer structure having more than two layers, a stray capacitance generated between the coils and the inductance of the coils constitute a parallel resonance circuit, and the tuning capacitance 25 can be made unnecessary or extremely small.

In addition, since the rectifier circuit 203 is configured as a full-wave rectifier circuit, the ripple is reduced, the smoothing capacity is also reduced, and the smoothing capacitor can be reduced in size and incorporated. It is possible to reduce the size.

As described above, in the close proximity wireless transfer card system according to the embodiment of the present invention, the R / W unit 1 And non-contact IC card 2
In between, power is transmitted wirelessly, and information transmission / reception (communication) is performed wirelessly.
That is, in the proximity wireless card system, the coil for the reader / writer or the spiral antenna 101
A power transmission wave or a communication wave is radiated, and the electromagnetic wave is received and induced by a coil or a spiral antenna 201 on the card side, a circuit on the card side is operated, and a signal is detected.

Incidentally, in the proximity wireless card system whose configuration has been described in detail above, the non-contact type
When the resistance of the spiral card antenna 201, which is the antenna of the C card 2, increases, the power consumed by the antenna itself increases as shown in FIG. In other words, the ratio of the power that can be supplied to the components, that is, the wireless chip 220 and the CPU + interface chip 210 is rapidly reduced.

However, according to various experiments by the present inventors, in order to secure a sufficient communication distance as the non-contact type IC card 2 used in the above-described close proximity wireless card system, the total power supplied ( It has been confirmed that it is preferable that the power supplied to the IC with respect to the total power supplied is approximately 60% or more. That is, in FIG. 5 described above, the DC voltage power supply 20 supplied from the power supply circuit 204 for the power supplied to the card antenna 201 is used.
It is preferable that the ratio of No. 5 be approximately 60% or more. More specifically, it is preferable that the resistance of the card antenna 201 be 10Ω or less.

Therefore, in the present invention, as an antenna for a non-contact type IC card, an antenna pattern or an antenna coil pattern is formed with a conductive paste on an insulating film, and the formed coil pattern is pressed or pressed.
By applying pressure under heating, good resistance characteristics can be obtained as the non-contact type IC card antenna.

That is, the conductor of the conductive paste formed by screen printing is made of metal particles having electrical conductivity (for example,
(Silver) together with a resin and a void for bonding these particles. Therefore, its resistance value is larger than that of an antenna made of a metal foil or a conductive wire. Therefore,
In the method of manufacturing an antenna pattern according to the present invention, the formed conductive paste is pressed, or is pressed under heating, thereby moving metal particles in the printed conductor to reduce voids, and thereby, the metal particles , The resistance of the antenna pattern due to the printing of the conductive paste is reduced. Also, on the surface of the printed conductor, the pressurization or the pressurization under heating reduces the unevenness, which also reduces the resistance of the printed conductor. This makes it possible to obtain good resistance characteristics as the non-contact type IC card antenna described above. In addition, as a specific method for performing the above-mentioned pressurization or pressurization under heating, for example, a hot press or a hot roll can be used.

The method of manufacturing an antenna pattern according to the present invention will be described in further detail. In the present embodiment, silver powder is used as metal powder, ethyl cellulose is used as binder, α-terpineol is used as solvent, and a small amount of A dispersing agent was added, and the mixture was kneaded with a so-called trimmer to obtain a conductive paste. Using the obtained conductive paste, as shown in FIG. 2 attached, on a polyester film having a thickness of 50 μm, a width of 1.5 mm, a pitch of 2.0 mm,
Spiral antenna pattern 3 with 7 turns
Was formed using a screen printer. Thereafter, the polyester film on which the antenna pattern was printed was dried at room temperature for about 1 hour, and then dried at 100 ° C. for 30 minutes with warm air.

The resistivity of the conductor of the antenna pattern 3 on the polyester film 4 obtained as described above is 30 μΩcm.
Met. As shown in FIG. 3, this is sandwiched between silicone-coated polyester films 5, 5, and between stainless steel plates 6, 6,... Having good surface smoothness (in this case, in two steps) at 120 ° C. The press was performed at a temperature of 15 minutes while changing the pressure. In FIG. 3, reference numeral 7 denotes an upper punch, reference numeral 7 'denotes a lower punch, and reference numerals 8 and 8.
Indicates heaters provided in the upper punch and the lower punch.

As a result, as shown in FIG. 4, as the applied pressure increases, the resistivity of the conductor of the printed antenna pattern 3 formed on the polyester film 4 decreases, and particularly, the conductor is 320 kg / cm ² or more. Therefore, according to the applied pressure, the resistivity of this printed conductor is 10 μΩcm,
Despite adopting conductive paste printing as a method of manufacturing an antenna pattern, it is possible to obtain a non-contact IC card and a low-resistance antenna having suitable resistance characteristics as the antenna pattern 3 thereof, that is, a card antenna 201. Was.

[0038]

As described above in detail, according to the present invention, as a method of manufacturing an antenna pattern of a non-contact type IC card of an external power supply type, an inexpensive and mass-producible conductive paste printing method is used. And, despite the printing of the conductive paste, the resistance characteristics of the obtained antenna pattern can be made suitable characteristics as a non-contact type IC card of an external power supply type. An excellent effect of realizing a low-cost and thin external power supply type non-contact IC card with low resistance, long communication distance, and low cost can be realized.

[Brief description of the drawings]

FIG. 1 is a characteristic diagram showing a change in a ratio of (IC supply power / total supply power) to an antenna resistance, which is a resistance characteristic of an external power supply non-contact IC card according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of an antenna print pattern of the external power supply type non-contact type IC card according to the embodiment.

FIG. 3 is a cross-sectional view showing an example of a press device used for manufacturing an antenna conductive pattern of the external power supply type non-contact type IC card according to the embodiment.

FIG. 4 is a diagram showing a change in resistivity of an obtained antenna conductive pattern with respect to a pressure applied by the press device shown in FIG. 4;

FIG. 5 is a block diagram showing an example of a close proximity wireless transfer card system using an external power supply type non-contact type IC card according to the embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 R / W unit 2 Non-contact IC card (wireless IC card) 3 Antenna pattern made of conductive paste 4 Polyester (insulating) film 5 Polyester film coated with silicon 6 Stainless steel plate 7 7 ′ Upper punch And lower punch 8 ... heater

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masami Makuuchi 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Hitachi, Ltd. Production Technology Research Laboratories (72) Koichi Uesaka 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa F-term in Hitachi, Ltd. Production Engineering Laboratory (reference) 4E351 AA01 BB09 BB31 CC11 CC31 DD05 DD51 EE12 EE24 GG06 5B035 AA04 BB09 BC02 BC03 CA01 CA06 CA12 CA23

Claims (6)

[Claims] 1. A semiconductor integrated circuit and a resin film substrate are sealed inside a plate-like housing of a predetermined size, and at least one of the resin film substrates sealed inside the plate-like housing. An antenna pattern is formed on the surface,
Thus, in a non-contact type IC card capable of receiving external power by electromagnetic waves through the antenna pattern and transmitting and receiving information signals from the outside, the antenna pattern formed on the surface of the resin film substrate Is a non-contact type IC card formed of a conductive paste with a resistivity of 10 μΩcm or less. 2. A semiconductor integrated circuit and a resin film substrate are sealed inside a plate-like housing of a predetermined size, and at least one of the resin film substrates sealed inside the plate-like housing. A non-contact IC card which has an antenna pattern formed on its surface and which can receive external power via the antenna pattern by electromagnetic waves and transmit and receive information signals from the outside. The antenna pattern formed on the surface of the film substrate is formed using a conductive paste, and the antenna pattern formed using the conductive paste is based on the total power supplied from the outside by the electromagnetic wave. A non-contact IC car, wherein the power supply to the semiconductor integrated circuit is set to have a resistance value of 60% or more. De. 3. The contactless IC card according to claim 1, wherein the antenna pattern has a resistance of 10Ω.
A non-contact type IC card characterized by the following. 4. The non-contact type IC card according to claim 1, wherein the antenna pattern formed on the surface of the resin film substrate is formed in a spiral shape. Non-contact IC card. 5. The method for manufacturing an antenna pattern in a non-contact type IC card according to claim 1 or 2, wherein a conductive paste is formed on at least one surface of the resin film substrate by screen printing. Then, the antenna pattern is formed by pressurizing or pressurizing under heating. 6. The method for manufacturing an antenna pattern according to claim 5, wherein the pressing is performed at 320 kg.
A method for manufacturing an antenna pattern, comprising forming a pressure at a pressure of not less than / cm ² .