Registers – Records – Laminated
Reexamination Certificate
1998-07-27
2001-01-16
Le, Thien M. (Department: 2876)
Registers
Records
Laminated
C235S492000
Reexamination Certificate
active
06173897
ABSTRACT:
In the field of personal cards containing a micro-processor, one distinguishes between contact cards wherein the terminal or Reader unit supplies electric power to the card chip by means of delicate contact feelers, and non-contact cards which receive the requisite electrical power by electromagnetic radiation or close proximity inductive transfer. The present paper relates to the latter type.
Also in this field, innovative efforts arose quite early, an example being the British patent GB 1,314,021 (Digital data carrying component and associable data transfer device) wherein it was intended to replace magnetic stripe cards by inductively-coupled card components in automatic fare assessment and collection installations, on railways and buses. Meanwhile, the demand for stored value cards evolved in many other fields as well. One can divide them into three groups, namely
(a) those cards which are required to be read, and written on, inside a machine so that the card, if invalid for one reason or another, can be retained. In such cases, the card is inserted through a slot and then drawn mechanically to the transaction location.
(b) cards required in situations where the emphasis is on user convenience and transaction speed; the card remains hand-held and passes the Reader at fairly close proximity (15-150 mm).
(c) cards which are in visual line with a Reader position at a distance of 1-10 metres, and are required to deliver a signal identifying the card holder to the interrogating station.
At present, no cards are available that could perform well in all of the named cases. While it is feasible for persons to carry several stored value cards, in practice this is an inconvenience and creates confusing accounting problems. It would be desirable to have to handle only one type of card for the various application cases. This would also avoid the need to install different update equipment for each card group.
There are, however, considerable obstacles to the producing of a single type of card capable of satisfying the above listed operation modes.
The aim of the present invention is to point out the principles for a non-contact energy and data transfer system which permits the card to be read at very close distance, at a medium range of proximity (say, 20 mm to 150 mm), as well as at a distance of several metres; using a card which can be manufactured at a low cost, will not age through frequent usage, will not deteriorate over time and will not generate electronic pollution through radiation.
It is not irrelevant from the economic point of view whether or not these apparently high-staged objectives are achieved or not. If they were shown to be non-achievable, this would mean a very large increase in the production of plastic cards and card Readers of different types. In terms of total cost, this may well exceed the total cost to the economy of minting coins and printing currency notes. This would contrast with the declared purpose of modem cards to reduce the overheads of value exchanges and trade.
In my preceding patent applications nr. 9605050.4 and 9606764.0 I have set out the design principles of an antenna module built into the card which would permit the use of a single card for the card groups (a) and (b) referred to in the introduction.
To this will now be added a demonstration of suitability of essentially the same antenna module also for card communication with a distant Reader Station. The description that follows is largely a repetition of the material already deposited (as quoted) although there are minor amendments and insertions. This is followed by a new chapter which explains how the card would perform responsive to a gigahertz electromagnetic communication channel.
For most financial transactions it would not be desirable for a Reader Emitter to power up a card at a distance of more than 3-4 inches. It would, on the other hand, be desirable that on bringing a card closer to the Reader Plate, there should be a steep rise in the injected power level, reaching its peak at about 2 inches distance. Upon approaching the Card Reader still further the power level should remain constant, or at least, nearly constant.
It is feasible to design a coupling system so that this is achieved, based on the provision that the Antenna is connected to an oscillator whose frequency is lower than the resonance frequency of the Reader Antenna. As the card antenna comes closer to the Reader Plate, the mutual inductance of the antenna pair increases, in such a manner that the joint resonance frequency coincides with the preset frequency of the Reader driving oscillator. This may be set to be the case at a distance of, say, two inches. If the user brings the card still closer to the Reader unit (beyond the critical coupling) the energy transfer would tend to become less efficient; however, the flux interlinkage would increase still further.
In balance, adequate power will be transferred to the Card between zero to 2½ inches proximity. In the absence of a card in its environment the Reader Antenna ‘falls asleep’, there will be but low radiation from the Reader. This would be further reduced because of a degree of mutual cancellation of the twin coils of the Reader Antenna at non-proximity distances. The
FIG. 5
of GB 2291725 indicates the basic circuitry in the card when receiving input from the Reader twin radiator elements which operate in antiphase.
In
FIG. 5
of the named patent, (reproduced on
FIG. 7
in this paper) the coupling elements are two capacitor pairs 180° out of phase; even the voltage parameters which characterise individual data its occur in the coupling pairs in opposite directions relative to a steady state condition. Their separate interface sections (
32
,
33
) produce therefrom a single input signal to a circuit group (
34
) which translates the signal into a high or low data bit, and into a clock pulse, both inputted to a microprocessor (
30
).
Whereas thus in close proximity (say, between 1 mm to 60 mm), the antiphased signals can be read out separately and become additively effective within the card antenna and connected circuits, at a spacing beyond 100 mm the two signal elements intermingle and cancel each other. (The behaviour at VHF frequencies will, however, have to be established experimentally.)
In the present paper, the capacitor plates are widened portions of the coil elements. It is envisaged that a coil is made of thin conductor stripes deposited on thin laminate insulating material of which the card is to be made up. The purpose of this arrangement is to avoid the strain on the coil material if it were constituted of solid wires or relatively thick metal deposits. It is reported that coils of the latter kind when subject to frequent bending, become brittle and develop discontinuities which understandably ruin the resonance effect.
By making the width of the inductive strips fairly wide, its thickness can be made small enough to avoid any undue strain during the bending of the card. It is no longer possible to accommodate several turns; however as will be seen it is possible to have a number of loops co-acting in parallel.
REFERENCES:
patent: 4795898 (1989-01-01), Berstein et al.
patent: 4835846 (1989-06-01), Juan et al.
patent: 4960983 (1990-10-01), Inoue
patent: 5434398 (1995-07-01), Goldberg
patent: 5436441 (1995-07-01), Inoue
patent: 5444222 (1995-08-01), Inoue
patent: 5587574 (1996-12-01), Van Geel
patent: 5594680 (1997-01-01), Ohtake et al.
patent: 5648761 (1997-07-01), Kreft et al.
patent: 5670772 (1997-09-01), Goto
patent: 5675658 (1997-10-01), Brittain
patent: 5698838 (1997-12-01), Yamaguchi
patent: 5821525 (1998-10-01), Takebayashi
patent: 5852289 (1998-12-01), Masahiko
Le Thien M.
Rothwell Figg Ernst & Manbeck
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