Registers – Coded record sensors – Holding devices
Reexamination Certificate
1999-01-19
2002-04-09
Lee, Michael G. (Department: 2876)
Registers
Coded record sensors
Holding devices
C235S493000, C235S492000
Reexamination Certificate
active
06367701
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a portable data transmission device for the transmission of electrical signals and/or data to a read-write station. The device has a data medium in which an electronic circuit with a data memory is integrated, and a coupling element, which is assigned to the electronic circuit and is arranged or supported in a predetermined spatial position relative to the electronic circuit. A fixing element is provided, which is at least partially matched to the outer dimensions of the data medium and which supports the data medium, on the one hand, and the coupling element, on the other hand, in the predetermined position with regard to the data medium.
The invention further pertains to a fixing element for supporting a coupling element a contactless smart card. The coupling element is thereby supported by the fixing element. An electronic circuit with a data memory and an induction coil that is electrically connected to the electronic circuit are integrated in the smart card.
The application possibilities of smart cards, which are designed, as a rule, in the check card format, have become extremely diverse on account of a high functional flexibility. They are continuing to increase with rising computer power and storage capacity of the available integrated circuits. In addition to the currently typical fields of application of such smart cards in the form of health insurance cards, flexitime recording cards, telephone cards and the like, in the future applications will emerge, in particular, in electronic payment transactions, in computer access control, in protected data stores and so on. With regard to the type of coupling to a terminal or a read-write station, a distinction is made between smart cards with contacts and so-called contactless smart cards. In the case of a smart card with contacts, contact is made by a metallic contact zone with contact areas which are standardized, usually according to an ISO standard. In addition, there are contactless smart cards which afford not only technical advantages over the smart card with contacts but also a range of interesting new application possibilities for the card issuer and the card co-user. Thus, contactless smart cards do not, for example, necessarily have to be inserted into a card reader, rather there are systems which function over a distance of a few meters. A broad area of application is that of local public transport, for example, where as many people as possible must be detected in the shortest possible time. In addition to other advantages, the contactless smart card affords the advantage that no technical elements are visible on the surface of the card, with the result that the visual configuration of the surface of the card is not limited by magnetic strips or contact areas.
The disadvantages of currently available contactless smart cards reside primarily in the additional components such as transmission coils or capacitor plates which have to be integrated in the card. Furthermore, the electronics required in the contactless smart card in order to contactlessly transmit electrical signals to the read-write station are relatively complex. Circuits which enable signal transmission by means of microwaves, optical signals, capacitive or inductive coupling are suitable, in principle, for this purpose, capacitive and inductive coupling being the most suitable owing to the flat design of the smart card. At the present time the transmission is effected inductively in most of the contactless cards, by which method both the data and the power transmission can be realized. Thus, one or more induction coils are integrated in the card body and make contact in a suitable manner with the circuit situated on the semiconductor chip. Electrical signals are transmitted according to the principle of the loosely coupled transformer, the carrier frequency lying, for example, in the range between 100 and 300 kHz or being a few MHz, in particular the industrial frequency of 13.56 MHz. This necessitates induction coils having coil areas of typically about 30 to 40 cm
2
, which are significantly larger than the base area of the semiconductor chip of the order of magnitude of about 10 mm
2
, the induction coil as a rule having only a few turns and being of planar design.
As a rule, the semiconductor components are mounted in the form of prefabricated modules or directly as a chip onto the etched coil. The chip module, which is present as a separate structural part, together with the induction coil is then laminated into the card body in order to complete the smart card, intermediate sheets in the form of inlay sheets being incorporated for volume equalization in the course of lamination, the intermediate sheets being provided with stamped-out portions, if appropriate. Limits are imposed on the conceivably possible arrangements and designs of the induction coil, firstly by the predetermined maximum structural height of about 840 &mgr;m of an ISO smart card and secondly on account of the predetermined bending properties according to the ISO standard, and so limits are imposed on the maximum magnetic flux density that can be achieved. An important parameter in contactless smart cards is the range, that is to say the maximum distance between smart card and read-write station within which the data transmission still functions entirely satisfactorily. Apart from the properties of the read-write station, the maximum possible range primarily depends on the matching of the induction coil within the smart card in relation to the semiconductor chip, and on the effective area of the induction coil, which operates as an antenna, the coil area naturally being limited on account of the predetermined size of the smart card.
European published patent application EP 0 691 625 describes a portable radio-frequency encapsulation of a smart card as described above. That encapsulation incorporates in it a battery-powered microcontroller circuit, which is used to enable the contactless transmission of data from the smart card to a reading unit. The data exchange from the smart card to the microcontroller circuit provided in the encapsulation is effected capacitively via capacitor plates. Voltage is supplied to the smart card by means of an inductive driver circuit which is provided in the encapsulation and also has a ferrite core.
German published patent application DE 44 01 089 describes a protective enclosure for contactless smart cards, in which the smart card is surrounded by a planar, in particular rectangular, enclosure. At least a partial region of the areas surrounding the card is electrically conductive. The protective enclosure enables contactless smart cards to be protected against unauthorized access.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a portable data transfer device for a smart card and an associated fixing element, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which improves the reading or writing security when the contactless smart card is guided past the read-write station and the maximum possible reading or writing distance can be increased.
With the foregoing and other objects in view there is provided, in accordance with the invention, a portable data transmission system for transmitting signals to a read-write station, comprising:
a contactless smart card with a card body having given outer dimensions and carrying an electronic circuit with a data memory and an induction coil integrated in the card body and electrically connected to the electronic circuit;
a fixing element having dimensions substantially matched to the given outer dimensions of the card body and being adapted to receive the smart card; and
a coupling element supported at the fixing element and having a defined spatial position relative to the electronic circuit when the smart card is received by the fixing element, the coupling element having magnetic material associated with the induction coil f
Cyr Daniel St.
Greenberg Laurence A.
Lee Michael G.
Lerner Herbert L.
Siemens Aktiengesellschaft
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