(19) 9
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`(12)
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`Europdisches Patentamt
`
`European PatentOffice
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`Office européen des brevets
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`(11)
`
`EP 1 031 939 At
`
`EUROPEANPATENT APPLICATION
`published in accordance with Art. 158(3) EPC
`
`(48) Date of publication:
`30.08.2000 Bulletin 2000/35
`
`(21) Application number: 98953057.1
`
`(22) Dateoffiling: 16.11.1998
`
`(84) Designated Contracting States:
`DE FR GB NL
`
`(30) Priority: 14.11.1997 JP 31394497
`14.11.1997 JP 31394597
`14.11.1997 JP 31394697
`
`(71) Applicant:
`ToppanPrinting Co., Ltd.
`Taito-ku Tokyo110-0016 (JP)
`
`(72) Inventors:
`» EMORI, Susumu
`Taito-ku Tokyo 110-0016 (JP)
`
`(61) Int. cl.’: GO6K 19/00
`
`(86) International application number:
`PCT/JP98/05142
`
`(87) International publication number:
`WO 99/26195 (27.05.1999 Gazette 1999/21)
`
`* NAKAJIMA, Hidemi
`Taito-ku Tokyo 110-0016 (JP)
`* IGARASHI, Susumu
`Taito-ku Tokyo 110-0016 (JP)
`* KOBAYASHI, Kazuo
`Taito-ku Tokyo 110-0016 (JP)
`
`(74) Representative:
`Leson, Thomas Johannes Alois, Dipl.-Ing.
`Patentanwalte
`
`Tiedtke-Bihling-Kinne & Partner,
`Bavariaring 4
`80336 Munchen (DE)
`
`
`
`(54)
`
`COMPOSITE IC MODULE AND COMPOSITEIC CARD
`
`(57)|Asmart card comprises an IC module and an
`prise first and second couplercoils, respectively, which
`antenna for non-contact transmission. The IC module
`are disposed to be closely coupled to each other, and
`the IC module and the antenna are coupled in a non-
`contact state by transformer coupling. An antennacoil is
`disposed so as not to overlap an engagementportion
`for the IC module, whichis a region of an external termi-
`nal electrode serving as a contact-type electrode, an
`embossing region, or a magnetic stripe region.
`
`has both a contact-type function and a non-contact-type
`function.
`In the contact-type function, power reception
`and signal
`transmission/reception is effected via an
`electrical contact.
`In the non-contact-type function,
`powerreception and signal transmission/reception is
`effected in a non-contact state by an electromagnetic
`coupling system without providing the IC card with an
`electrical contact. The IC module and the antenna com-
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`EP1031939Al
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`Printed by Xerox (UK) Business Services
`2.16.7 (HRS)/3.6
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`Infineon Exhibit 1010
`Infineon Exhibit 1010
`Infineon v. AmaTech
`Infineon v. AmaTech
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`

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`EP 1 031 939 A1
`
`Description
`
`Technical Field
`
`The present invention relates to a smart card having both a function of a contact type in which reception of
`(0001)
`supply power, transmission/reception of signals, etc. are performed via an electrical contact, and a function of a non-
`contact type in which reception of supply power, transmission/reception of signals, etc. are performed without provision
`of an electrical contact, in an information recording medium represented by IC cards, etc. used in fields such as office
`automation (OA), factory automation (FA) or security. The present invention also relates to an IC module used for the
`smart card.
`
`Background Art
`
`information recording media with
`With the advent of IC cards including semiconductor memories, etc.,
`[0002]
`greatly increased memory capacities, compared to conventional magnetic cards, etc., have been realized. In addition,
`with internal provision of a semiconductor integrated circuit device such as a microcomputer, an IC card itself has an
`arithmetic process function and this provides high security to the information recording medium.
`[0003]
`The IC cards areinternationally standardized by the ISO (International Organization for Standardization). In
`general, in an IC card, an IC such as a semiconductor memoryis built in a card body formed of a plastic material as a
`basic material and metallic conductive terminal electrodes are provided on a card surface for connection with an exter-
`nal read/write apparatus. In order to effect data communication betweenthe IC card and external read/write apparatus,
`the IC card is inserted in a card slot of the external read/write apparatus and the terminal electrodes of the IC card are
`connected to the external read/write apparatus.
`[0004]
`This is suitable for uses requiring security and safety for communication as in large-volume data exchange
`and banking processing, for example, uses for crediting and electronic wallets.
`[0005]
`Onthe other hand, whenthe IC card is applied to gate management for entrance/exit, etc., the main purpose
`for communicationis identification and in most cases the amount of communication data is small. Accordingly, simple
`processingis desired. To solve this problem, a non-contact type IC card has been devised.
`[0006]
`With this type of IC card, an oscillation energy field of high-frequency electromagnetism, ultrasonics,light,
`etc. is provided in the space. The energy is absorbed and converted to an AC power. The AC poweris rectified toa DC
`sourcefordriving an electroniccircuit provided in the card. The frequency of an AC componentin thefield may be used
`as it is, or multiplied or divided to produce anidentification signal. The identification signal is transmitted as data to an
`information processing circuit formed of a semiconductor device via a coupler such as an antenna coil or a capacitive
`element.
`
`In particular, most of non-contact type IC cards designedforidentification or simple numerical data process-
`[0007]
`ing are associated with Radio FrequencyIdentification (RF-ID) of a hard logic which does not have a battery cell anda
`CPU (Central Processing Unit). With the advent of the non-contact type IC card, safety from forgery or falsification is
`enhanced, compared with magnetic cards. Moreover, whena carrier of the card passes through a gate,it should suffice
`if the carrier approaches the card to an antenna unit of the read/write apparatus attached to the gate apparatus or
`brings the card into contact with the antennaunit of the read/write apparatus. The carrier does not have to do time-con-
`suming operations of taking the card out of the case andinsertingit in the slot in the read/write apparatus.
`[0008]
`Recently, in order to apply a single card to many purposes, a smart card has been devised which has the
`former contact type function with external terminals and the latter non-contact type function with radio-frequency data
`communication. This smart card has advantagesof both types,i.e. high security of the contact type which is realized
`by CPU processing and convenience of the non-contact type.
`In either the non-contact type or the composite type,
`where a powersupply is provided in the IC card, there is no need to obtain powerfrom the aforementioned oscillation
`energyfield in the space.
`[0009]
`A general mounting method for the smart card will be described blow.
`[0010]
`A metallic foil antenna coil for non-contact transmission, which is formed by etching, is sandwiched between
`a sheet with engagementhole for an IC module and a substrate. The structure is laminated to produce a card body. In
`this case, two antenna terminals for connection between the antennacoil and the IC module are exposedto an inside
`of the engagementhole in the card body.
`[0011]
`Metallic terminal electrodes for connection with an external apparatus are provided on one surfaceof the IC
`module. The other surface is provided with an IC and terminals for connection with the antenna. A conductive adhesive
`is applied to the terminals. The IC module is mounted in the engagement hole in the card body such that the terminals
`with the conductive adhesive may overlap the antenna terminals of the card, and then the terminals of the IC module
`are connected to the antenna terminals with heat and pressure. Thus, the mounting is completed.
`[0012]
`This mounting method is relatively simple. However,it is difficult to confirm the state of the connection por-
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`EP 1 031 939 A1
`
`tion between the IC module and antenna, and a problem remains with the reliability of connection. In addition, degra-
`dation in the connection portion may easily occur due to mechanical stress. Moreover, since a step for applying the
`conductive adhesive and a thermocompression step are required for the connection between the IC module and
`antenna,it is difficult to use an apparatus for manufacturing a conventional IC card with external terminals. It is thus
`necessary to provide a new manufacturingline.
`[0013]
`In addition, in most of IC cards with the non-contact-type transmission mechanism, an emboss or a mag-
`netic stripe cannot be applied due to restrictions of the coil shape, etc. for keeping reception power. In orderto fully meet
`a demand onthe market, the emboss and magnetic stripe have to be considered. Techniques which do not permit pro-
`vision of an emboss or a magnetic stripe are restricted in the range of application.
`[0014]
`Anon-contact-type IC card disclosed, for example, in Jpn. Pat. Appin. KOKAI Publication No. 8-227,447per-
`mits provision of an emboss and a magnetic stripe. Specifically, a non-contact-type IC card having an outer shape
`according to ISO 7811 is provided. In order to provide a magnetic stripe and an emboss onthe card, a communication
`IC module is constructed such that an IC mount portion, a power receiving coil and a data transmission/receptioncoil
`are arrangedin a longitudinal direction on a region excluding the magnetic stripe region and embossing region.
`[0015]
`The reception coil and communication coil of the communication IC module are comprised of single-layer
`coils formed by electrocasting. Both are buried in a single strip-like substrate. Lead portions for connection with pads of
`the IC chip are formed of eachcoil.
`[0016]
`The IC chip is mounted onthe strip-like substrate suchthat a circuit surface of the IC chip is opposed to the
`strip-like substrate. The lead portions are bump-bonded to the IC pads and a gap betweenthe strip-like substrate and
`IC chip is filled with a potting resin for fixation. An inner end portion of the coil and an end portion of an internal-end lead
`are jumper-bonded by an enamel copperwire. The bondingis effected by instantaneous thermocompression and ter-
`minal portions are protected with potting resin.
`[0017]
`A methodof integrating this communication IC module and the card is described. According to this method,
`there are providedafirst sheet for covering the upper surface, a second sheet having the samethicknessasthe strip-
`26
`like substrate and having a windowwith a strip-like outer shape, a third sheet having a windowfor passing the IC chip
`and a window for passinga first jumper-bonding portion, a fourth sheet having only a window for passing the IC chip,
`andafifth sheet for covering the lower surface(all formed of vinyl chloride). The communication module is sandwiched
`by the respective sheets and subjected to thermocompression. Thus, the communication module is integrated in the
`card.
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`Although the above technique is applicable to the non-contact-type IC card, it is not applicable to the smart
`[0018]
`card having external terminals.
`[0019]
`The positions of the terminals of the card with external terminals are specified by ISO 7816. FIG. 1 shows a
`magnetic stripe region, an embossing region and an external terminal region specified by ISO 7816. In the smart card,
`an IC module is mounted on the external terminal region. In FIG. 1, in the regions indicated by hatching, mounting of
`an antennafor non-contact coupling is prohibited.
`[0020]
`ISO 7816 specifies an outer long side to be 85.47-85.72 mm, an outer short side to be 53.29-54.03 mm. The
`magnetic stripe region is defined in an area of 15.82 mm from the upper side. The embossing region is defined in an
`area of 24 mm from the lower side, 6.0 mm from theleft side, and 8.0 mm from the right side. The external terminals
`are formedin an area of 28.55 mm from the upper side and 19.87 mm from the left side.
`[0021]
`For example, Jpn. Pat. Appin. KOKAI Publication No. 7-239,922 discloses a prior-art technique of a smart
`card realizing a magnetic stripe and embossing.
`[0022]
`Accordingto this technique, the IC modulefor the IC card comprises an IC chip; a transmission mechanism
`connected to the IC chip for effecting transmission of information and/or powerwith the external apparatus; and a sup-
`port memberfor supporting the IC chip and transmission mechanism. The transmission mechanism comprises a non-
`contact-type transmission mechanism having a coil or an antenna, and a contact-type transmission mechanism having
`a plurality of terminal electrodes of patterned conductors provided on a surface of the support member. This document
`teachesthat since the functions compatible with the contact type and non-contact type are constructed as a module and
`this IC module is fitted and fixed in a plastic card body, the magnetic stripe and embossing can be made without hin-
`drance.
`
`The documentfurther discloses, as mounting means, that the antennaor coil for non-contact transmission
`[0023]
`is provided so as to surround the terminal electrodes, and alternatively the antennais positioned at the center and the
`terminal electrodes are provided around the antenna.
`[0024]
`Specifically, the non-contact transmission antennais contained in the IC module and thereby the connection
`betweenthe antenna coil and the IC module is omitted in the final step.
`[0025]
`In view of the standard illustrated in FIG. 1, however, it is clear that the method in which the antennacoil is
`provided around the terminal electrodes is not feasible. More specifically, in the method in which the non-contact trans-
`mission antennais contained in the IC module, an adequate antenna area is not obtained, and this permits only a so-
`called close-contact mode in which the distance for communication is several mm orless.
`
`

`

`EP 1 031 939 A1
`
`Since the distance betweenthe terminal electrodes and embossing region is 1.45 mm at maximum,it is not
`[0026]
`practical to dispose the antennaorcoil so as to surround the terminal electrodes without overlapping the terminal elec-
`trodes, as will be described below.
`In the case where the antenna coil is disposed around the external terminals, the
`maximum outside diameter and minimum inside diameter of the coil are @12 mm and @9.3 mm,respectively. If the
`antenna coil is formed of a print pattern in this region, where the pattern width and interval are 0.15 mm and 0.1 mm
`respectively, the numberof turns and the inductance become about four and 0.4 wH, and six and 1.0 wH in respective
`cases (yH denotes microhenry). Where the coil is disposed around the outer periphery of the terminal electrodes while
`the embossing region maintained, only several turns are obtained even with the formation ofthe print coil. Owing to the
`smallness of the area of the coil, too, adequate power cannot be obtained and only close coupling is permitted with a
`communication distance being several mm orless.
`[0027]
`In this case, the merit of adding the non-contact transmission function is small. The merit of adding the non-
`contact transmission mechanism to the contact type transmission mechanism is obtained with a communication dis-
`tance exceeding several-ten mm to 100 mm. Communication is achieved if the card is exposed to the antenna unit of
`the external read/write apparatus within such an area. For this purpose,it is necessary to increase the area of thecoil
`or the numberof turns.
`
`In brief, where the coil is disposed around the outer periphery of the terminal electrodes within the IC mod-
`[0028]
`ule, only several turns are obtained evenif the print coil is formed, and owing to the smallness of the area of thecoil,
`too, adequate power cannot be obtained. Moreover,if a practical numberof turns is to be obtained with a conductor pat-
`tern, it overlaps the embossing region.
`[0029]
`Onthe other hand, in the case of the latter mounting means wherein the terminal electrodes are disposed
`around the antenna, the embossing area is obviously occupied and the standard of the IC card with external terminals,
`ISO 7816, is not at all satisfied. The likelihood of acceptancein the marketis very low.
`[0030]
`Since the smart card is associated with weak radio waves, there is a demand to enhance powertransmis-
`sion efficiency. Prior-art techniques for this purpose are described, for example, in Jpn. Pat. Appin. KOKAI Publication
`No. 2-7,838 and Jpn. Pat. Appin. KOKAI Publication No. 63-224,635.
`In these prior-art methods for enhancing the
`powertransmission efficiency, however, attention is paid only to transmission power and these methodsare effective
`only in cases where the transmission-side power efficiency can be improved and more power be sent out. Conse-
`quently, wherethe intensity of a radiant electromagneticfield is limited, these methods do not contribute to the improve-
`mentin the reception-side powerreceptionefficiency. In order to improve the powerreception performanceof the smart
`card located in a weak electromagnetic field with the non-contact type function of the IC card itself, it is necessary to
`provide the card with meansfor absorbing moreradiation energy.
`[0031]
`Furthermore, since the smart card includes a semiconductor integrated circuit, acquisition of more current
`with less poweris desirable for reduction of a load on the powersupply circuit. In order words,it is desirable to lower
`the power-reception side impedance. In the prior art, however, attentionis paid only to the transmission voltage and not
`to the powerreception side.
`[0032]
`A first object of the present invention is to overcome the problemsin the prior art and provide an IC module
`having reception sensitivity enough to obtain an adequate communication distance, despite no wired connection dis-
`posed between the IC module and a non-contact transmission antenna, and being capable of maintaining both a con-
`tact-type and a non-contact-type transmission mechanism in practical operation states, and to provide a smart card
`including the IC module.
`[0033]
`A second object of the present invention is provide a smart card having both functions of contact type and
`non-contact type and being capable of performing at least either of power reception or signal transmission/reception in
`a non-contact mode, wherein the carrier wave reception efficiency on the smart card side is enhanced by a coupler in
`which a powertransmission side (reader/writer side) coil is separated from a power reception side (smart card side)
`antenna with an air gap, thereby improving powerefficiency on the power reception side (or signal transmission effi-
`ciency) and performing impedance conversion, and to provide an IC module for the smart card.
`[0034]
`A third object of the inventionis to provide an IC module and a smart card having both a contact-type trans-
`mission mechanism and a non-contact-type transmission mechanism and having a magnetic stripe and an embossed
`portion on a surfaceof the card, wherein power-reception-side powerefficiencyis improved and impedanceconversion
`is effected without adversely affecting formation of the magnetic stripe and embossed portion and the thicknessof the
`card can be reduced.
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`Disclosure of Invention
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`[0035]
`
`(1) A smart card according to the present invention has both a function of a contact type and a function of a non-
`contact type, the smart card comprising an IC module and an antenna element. The IC module comprises an IC
`
`

`

`EP 1 031 939 A1
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`chip incorporating a contact-type transmission function and a non-contact-type transmission function, and a mod-
`ule substrate having an external terminal serving as a contact-type transmission element andafirst couplercoil.
`The antenna element comprises an antenna for performing at least one of power reception and signal transmis-
`sion/reception with an external read/write apparatus, and a second couplercoil connected to said antenna. Thefirst
`coupler coil of the IC module and the second couplercoil of the antenna element for non-contact transmission are
`disposed to be closely coupled to each other, and the IC module and the antenna element are coupled in a non-
`contact mannerby transformer coupling.
`(2) According to the invention, in the smart card described in (1), the antenna element has a capacitive element.
`(3) According to the invention, the smart card described in (1) or (2) further comprises an embossing region. The
`IC module is provided at a substantially central portion of one shorter side of the card, and the embossing region
`is provided along one longerside of the card. The antenna for non-contact transmission is provided so as not to
`interfere with an external terminal region of the IC module and the embossing region.
`(4) According to the invention, the smart card described in (1) or (2) further comprises an embossing region. The
`IC module is provided at a substantially central portion of one shorter side of the card, and the embossing region
`is provided along one longerside of the card. The antenna for non-contact transmission is provided so as not to
`interfere with an external terminal region of the IC module and the embossing region. The antennais provided at a
`region defined by a longer side of the card opposed to the one longer side along which the embossing region is
`provided, a boundary of the embossing region on aninnerside of the card, a boundary of the external terminal
`region of the IC module ontheinnerside of the card, and a shorter side of the card opposedto the one shorter side
`at which the IC module is provided.
`(5) According to the invention, the smart card described in (1) or (2) further comprises an embossing region. The
`IC module is provided at a substantially central portion of one shorter side of the card, and the embossing region
`is provided along onelongerside of the card. At least a portion of the antenna for non-contact transmissionis dis-
`posed between the embossing region and an edge of the card and between an external terminal region of the IC
`module and an edge of the card, and along a periphery of the card so as notto interfere with the external terminal
`region of the IC module and the embossing region.
`(6) Accordingto the invention, the smart card described in (1) or (2) further comprises a magnetic stripe region and
`an embossing region. The IC module is provided at a substantially central portion of one shorterside of the card,
`the embossing region is provided along one longer side of the card, and the magnetic stripe region is provided
`along the other longer side of the card. The antenna for non-contact transmission is provided so as notto interfere
`with an external terminal region of the IC module, the embossing region, and the magnetic stripe region.
`(7) Accordingto the invention, the smart card described in (1) or (2) further comprises a magneticstripe region and
`an embossing region. The IC module is provided at a substantially central portion of one shorterside of the card,
`the embossing region is provided along one longer side of the card, and the magnetic stripe region is provided
`along the other longerside of the card. The antenna for non-contact transmission is provided substantially along a
`boundary of the magnetic stripe region on aninner side of the card, a boundary of the embossing region on an
`outer peripheral side of the card, and a boundary of an external terminal region of the IC module on the outer
`peripheralside of the card, so as notto interfere with an external terminal region of the IC module, the embossing
`region, and the magnetic stripe region.
`(8) Accordingto the invention, the smart card described in (1) or (2) further comprises a magnetic stripe region and
`an embossing region. The |C module is provided at a substantially central portion of one shorter side of the card,
`the embossing region is provided along one longer side of the card, and the magnetic stripe region is provided
`along the other longerside of the card. The antenna for non-contact transmission is provided at a region defined
`by a boundary of the embossing region on an innerside of the card, a boundary of an external terminal region of
`the IC module on theinner side of the card, a boundary of the magnetic stripe region on the innerside of the card
`and a shorter side opposed to said one shorter side at which the IC module is provided, so as not to interfere with
`an external terminal region of the IC module, the embossing region, and the magnetic stripe region.
`(9) According to the invention, in the smart card describedin (1) or (2), the second couplercoil of the antenna ele-
`mentis disposed outside a loop of the antenna.
`(10) An IC module accordingto the present invention comprises an IC chip incorporating a non-contact-type trans-
`mission function and a contact-type transmission function, and a module substrate having a first coupler coil and
`an external terminal serving as a contact-type transmission element. The first coupler coil is provided on a side of
`the module substrate which is opposite to a side on whichthe external terminal is provided, and is formed of a wind-
`ing coil fabricated by winding conductor wire coated with an insulation film.
`(11) Accordingto the invention, in the IC module described in (10), the windingcoil is spirally wound on at least one
`of a periphery and a vicinity of the IC chip.
`(12) According to the invention, in the IC module described in (10), the winding coil is toroidally wound on at least
`one of a periphery anda vicinity of the IC chip.
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`EP 1 031 939 A1
`
`in the IC module described in (10), the winding coil is wound around an outer
`(13) According to the invention,
`peripheral, end face of the module substrate.
`(14) Accordingto the invention, in the IC module described in any oneof (10) to (18), the IC chip and the first cou-
`pler coil are resin-sealed on a side of the IC module on which the IC chip is mounted.
`(15) According to the invention, in the |C module described in any one of (10) to (18), a size of the module substrate
`is substantially equal to a size of a region of the external terminal.
`(16) An IG module according to the present invention comprises an IC chip incorporating a contact-type transmis-
`sion function and a non-contact-type transmission function, and a module substrate havingafirst coupler coil and
`an external terminal serving as a contact-type transmission element. Thefirst couplercoil is formed of a patterned
`conductor on a side of the module substrate which is opposite to a side on which the external terminal is provided,
`and is disposed onat least one of a periphery andavicinity of the IC chip.
`(17) Accordingto the invention, in the IC module described in (16), the coil is wound around a seal memberof the
`IC chip in at least one of a spiral manner and a toroidal manner.
`(18) Accordingto the invention, in the IC module described in (16), the IC chip and the first coupler coil are resin-
`sealed onaside of the IC module on which the IC chip is mounted.
`(19) According to the invention, in the IC module described in (16), a size of the module substrate is substantially
`equalto a size of a region of the external terminal.
`
`Brief Description of Drawings
`
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`[0036]
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`FIG. 1 shows dimensionsof a card with an external terminal, as stipulated by ISO 7816;
`FIG. 2 shows an equivalent circuit of a non-contact coupler circuit for describing the principle of a non-contact
`transmission mechanism according to the presentinvention;
`FIG. 3A and FIG. 3B are an exploded perspective view and a cross-sectional view showing a structureofafirst
`embodiment of a smart card according to the present invention;
`FIG. 4 showsa first example of arrangement of an antenna coil accordingto the first embodiment;
`FIG. 5 shows a second example of arrangementof the antenna coil accordingto the first embodiment;
`FIG. 6 showsa third example of arrangementof the antennacoil according to the first embodiment;
`FIG. 7 shows a fourth example of arrangement of the antenna coil according to the first embodiment;
`FIG. 8A and FIG. 8B are an exploded perspective view and a cross-sectional view showing a structure of a second
`embodiment of a smart card according to the present invention;
`FIG. 9 showsa first example of arrangement of an antenna coil according to the second embodiment;
`FIG. 10 shows a second example of arrangementof the antenna coil according to the second embodiment;
`FIG. 11 showsa third example of arrangementof the antenna coil according to the second embodiment;
`FIG. 12A and FIG. 12B are an exploded perspective view and a cross-sectional view showing a structureof a third
`embodiment of a smart card according to the present invention;
`FIG. 13 showsa first example of arrangement of an antennacoil according to the third embodiment;
`FIG. 14 shows a second example of arrangement of the antenna coil according to the third embodiment;
`FIG. 15A and FIG. 15B showathird example of arrangement of the antennacoil according to the third embodiment;
`FIG. 16A and FIG. 16B show a first example of the structure of a capacitive element in the present invention;
`FIG. 17A and FIG. 17B show a second example of the structure of the capacitive elementin the presentinvention;
`and
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`45
`FIG. 18A and FIG. 18B showathird example of the structure of the capacitive element in the presentinvention.
`
`Best Mode for Carrying Out the Invention
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`Embodiments of the smart card according to the present invention will now be described with reference to
`[0037]
`the accompanying drawings.
`[0038]
`To begin with, the basic structure and basic principle of a non-contact transmission mechanism will be
`described.
`
`FIG. 2 shows an equivalent circuit of a non-contact coupler circuit for describing the principle of the non-con-
`[0039]
`tact transmission mechanism according to the present invention. A transmission/reception circuit 101 of a non-contact
`type external read/write apparatus 100 is connected to a transmission/reception coil 102 which is an electromagnetic
`coupler for supplying powerto, and exchanging information with, the non-contact transmission mechanism in the smart
`card.
`
`[0040]
`
`Onthe other hand, the non-contact transmission mechanism of the smart card 1 comprises an antennacoil
`
`

`

`EP 1 031 939 A1
`
`4, connected electromagnetically and directly to the transmission/reception antenna 102 of the external read/write
`apparatus 100, for receiving power and exchanging information; a capacitive element 15 connected between both ends
`of the antennacoil 4 to constitute a parallel resonancecircuit; an IC chip 6 mounted on an IC module 2; a first coupler
`coil 8 connected to the IC chip 6; and a second couplercoil 3 closely coupled and disposed to transmit a signal received
`by the antennacoil 4 to the first coupler coil 8 with a maximum efficiency and connected between both ends of the
`capacitive element 15 of the parallel resonancecircuit.
`[0041]
`Although the capacitive element 15 is connected in parallel to the antenna coil 4, it may preferably be con-
`nected in series betweenthe antenna coil 4 and second couplercoil 3. If the parasitic capacity is increased, the capac-
`itive element 15 can be dispensed with.
`[0042]
`Coupling among the respectivecoils will now be described, referring to a case where powerand information
`is transmitted from the external read/write apparatus 100 to the smart card 1.
`[0043]
`A high-frequency magnetic field is induced in the transmission/reception coil 102 by a high-frequency signal
`(not shown) produced by the transmission/reception circuit 101 of the external read/write apparatus 100. This high-fre-
`quencysignal is radiated to the space as magnetic energy.
`[0044]
`If the smart card 1 is located in the high-frequency magnetic field at this time, a current is caused to flow in
`the parallel resonancecircuit, which comprises the antenna coil 4 and capacitive element 15 of the smart card 1, due
`to the high-frequency magnetic field produced by the transmission/reception coil 102 of the external read/write appara-
`tus 100. In this case, currents due to the high-frequency magnetic field are also inducedin the first coupler coil 8 con-
`nected directly to the IC chip 6 and the second coupler coil 3 connected to the resonancecircuit of the antennacoil 4
`and capacitive element 15 to transmit powerto thefirst coupler coil 8. The amount of induced currents in this caseis
`less than that of current inducedin the antennacoil 4 by an order of magnitude, and accordingly the sensitivity of recep-
`tion depends greatly on characteristics of the antenna coil 4.
`[0045]
`A signal received by the resonancecircuit of the antenna coil 4 and capacitive element 15 is transmitted to
`the second couplercoil 3. Since the second coupler coil 3 and first coupler coil 8 are closely coupled and disposed with
`a maximum transmissionefficiency, the signal is then transmitted to the IC chip 6 via transformer coupling of the second
`couplercoil 3 andfirst coupler coil 8. The maximum t