Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02279176 1999-07-27
Transmiasxo~a module for a transponder device and also a
trausponder device and method of operating a trangponder
device
The present invention relates to a transmission module for
contact-free data transmission between a chip and a reading
device in accordance with Claim 1 or 2 and also to a
transponder device cornprieing a transponder unit and a
transmission module according to Claims 12, 12 or 13 and a
method of operating a transponder device comprising a
transponder unit and a transmission module according to
Claim 16 or 17.
Transponder units, which in their simplest form comprise a
chip and a transponder coil in contact with the terminal
areas of the chip, are used to an increasing extent in
quite different fields, wherein they uniformly serve,
however, the purpose of ensuring a contact-free or wire-
free communication between a reading device disposed more
or leas remotely from the transponder unit and the chip in
order to make possible a data retrieval for the purpose of
detecting data stored on the chip. Such transponder units
are used, for example, in so-called contact-free chip
cards, in coded labels or even for identifying animals ~or
slaughter, in this case used as so-called injection
transponders.
The different fields of application of transponder units
result in some cases zn transmission distances which are
extremely mutually different between the respective
transponder unit and the associated reading device, which
distances accordingly require different operating voltages
o~ the transponder units or of the chip comprised therein.
In addition, it has hitherto been necessary to watch the
layout of the transponder unit to the reading device in
each individual case, which, ae a rule, makes an impedance
matching between the transponder unit and the. reading
device necessary. From the above it becomes clear that even
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on the basis of the two reading parameters, operating
voltage and impedance, alone, a multiplicity of differently
laid-out transponder units is necessary in order to ensure
a reliable operation of the respective transponder unit as
a function of the transmission distance and the nature of
the associated reading device. These requirements are
therefore an obstacle to a fundamentally desirable
standardization in the layout of transpvnder units, which
standardization would make possible an essentially cheaper
production of transponder unite. .
The object of the present invention is therefore to make
possible the design of a standardized transponder unit
regardless of the transmission distance encountered in an
individual case or of the respective type of reading
device.
This object is achieved by a transmission module having the
features of Claim 1 or 2.
According to the invention, a transmission module for the
contact-free data transmission between a chip and a reading
device is proposed which comprises a coil arrangement
having a coupling element and at least one aerial cvzl
which are electrically interconnected, wherein the coupling
element serves to produce an inductive coupling to a
transponder coil electrically connected to the chip and the
aerial coil serves to produce a contact-free connection to
the reading device. In this arrangement, the coupling
element designed as coupling coil and the aerial coil are
~of dzfferent design in regard to at least one of their coil
parameters which influence the coil impedance_
A transmission module which is constructed in this way and
which can be combined with the transponder unit by means of
inductive Coupling consequently makes possible an impedance
matching between the reading device and the transponder
CA 02279176 1999-07-27
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unit. That means that, proceeding from a standardized
transpvnder unit, matching can take place to a reading
device impedance which is different from the impedance of
the transponder unit in that the coupling coil is
essentially identical in regard to ita impedance to the
impedance o~ the transponder unit, and the aerial coil
connected electrically to the coupling coil is matched to
the impedance of the reading device in regard to its
impedance. Consequently) as a result of an appropriate
design of the coil parametexg of coupling coil and aerial
coil, it is possible to combine one and the same
transponder unit with reading devices differing from one
another in regard to their impedance. Available ae such
coil parameters which influence the impedance of the
respective coil in the design of the coupling element as
coupling coil are, for example, the wire cross section of
the coil, the length of the coil wire associated with the
respective coil or even the material used to produce the
coil wire.
According to the invention, a further possibility of
matching a transponder unit to the particular conditions of
the individual case in regard to different transmission
distances is to provide, according to Claim 2, a
transmission module for Che contact-free data transmission
between a chip and a reading device which comprises a coil
arrangement having a Coupling element and at least one
aerial coil, wherein the coupling element serves to produce
an inductive coupling to a transponder coil electrically
connected to the chip and the aexial coil to produce a
contact-free connection to the reading device, wherein the
contact element designed as coupling coil is designed in
such a way that the coupling coil serves as primary coil of
a transfvrrner formed with the associated transponder coil
to induce an increased operating voltage in the chip of the
transponder unit.
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In the case of this achievement according to the invention,
use is accordingly made of the inductive coupling between
the coupling coil anc~ the transponder coil in order to form
from the coupling coil and the transponder coil a
S transformer with which the operating voltage in the
transponder unit can be increased. Consequently, it becomes
possible, proceeding from a transponder unit with a
standardized layout, to span different transmission
distances as a result of the fact that correspondingly
differently laid-out transmission modules are used in such
a way that a suitable ratio of the number of turns between
the coupling coil and the transponder coil determines the
transformation ratio necessary to overcome the respective
transmission distance.
rn addition to the abovementioned possibility of achieving
an increased operating voltage in the transponder unit by a
suitable specification of the number of.
turns/transformation ratio, there is also the possibility
of amplifying quite generally the magnetic field of the
coupling coil by means of a suitable amplification device
in order thereby to achieve a correspondingly increased
induction and a voltage increase, associated therewith, in
the transponder unit. Such an amplification device may be
formed from a voltage source which increases or generates
the voltage applied to the coupling coil) that is to say)
for instance, by a battery disposed in the transmission
module and in contact with the coupling coil. This makes it
possible to form an active transmission module which has
its own voltage supply.
A further possibility for achieving an amplification effect
is to provide the coupling coil with a core made of a
permeable material, in particular ferrite, which core
increases the magnetic field strength of the coupling coil_
The amplification device described above consequently also
forms an achievement which is independent of, the
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achievement of utilizing the coupling coil and the
transponder coil to form a transformer.
In a particular embodiment of the transmission module which
uses a permeable material rod as core to form an axially
aligned magnetic field, the aerial coil serves
simultaneously as coupling coil_
To make possible a use of the coil arrangement as
transmission module and a simplified application of the
coil arrangement on a transponder unit or a substrate of a
transpvnder unit, the coil arrangement is disposed on a
carrier film. The term "carrier film" is in this case not
to be understood as restrictive in regard to a material.
choice suitable for the carrier film, that is to say, in
contrast to a widespread understanding of the meaning of
the term 'carrier film", as used here, this teen includes
not only plastic materials, but also natural materials,
such as, for example, cellulose or paper. Here) the term
"carrier film" is solely intended to express the fact that
a substrate formed as Carrier film is essentially
determined by its area dimension and has a thickness which
is on the negligible side compared with the area dimension.
For certain application cases) for example for producing a
chip card provided wzth such a transcnission module, it is
advantageous to design the coil arrangement in total as a
card inlay.
Xf the cozl arrangement is to be used in coded labels or
the like, it proves advantageous if the coil arrangement is
formed on an adhesive substrate_
According to Claim 11, the transponder device according to
the invention is provided with a transponder unit and a
transmission module, wherein the transponder unit comprises
a chip having a transpvnder cozl electrically connected to
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the chip and the transmission module comprises a coupling
element having an aerial coil) wherein the coupling element
serves to produce an inductive coupling to the transponder
coil, and the aerial coil is electrically connected to the
coupling element and serves to produce a contact-free
connection to a reading device, wherein, to make possible a
matching between the transponder unit and the reading
device, the coupling element, designed as coupling coil,
and the aerial coil axe of different design in regard to at
least one of their parameters influencing the coil
impedance. The advantages of such a transponder device
provided with a transmission module have already been
explained in detail at the outset.
Furthermore, according to the invention, a tranaponder
device comprising a transponder unit and a transmission
module is proposed according to Claim 12, wherein the
transponder unit comprises a chip having a transponder coil
electrically connected to the chip and the transmiaeion
module comprises a coupling element having an aerial coil,
wherein the coupling element serves to produce an inductive
coupling to the transponder coil, and the aerial coil is
electrically connected to the coupling element and serves
to produce a contact-free connection to a reading device,
2S wherein the coupling element is designed as coupling coil
and has a comparatively lowex number of turns than the
transponder coil, in such a way that the coupling coil
forms a primary coil and the transponder coil a secondary
coil of a transformer.
The advantages of such a transponder device provided with a
transmission module in conjunction with a possible increase
thereby of the operating voltage of the traneponder unit
have already been discussed in detail at the outset.
A further transponder device according to the invention is
provided, according to Claim 13, with a transponder unit
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and a transmission module, wherein the transponder unit
comprises a chip having a transponder coil electrically
Connected to the chip and the transmission module comprises
a coupling element having an aerial coil, wherein the
coupling element serves to produce an inductive coupling to
the transponder coil, and the aerial coil is electrically
connected to the coupling element and serves to produce a
contact-free connection tv a reading device, wherein the
coupling element is formed from a permeable material rod)
in particular a ferrite core, whose end face serves as.
coupling surface and the aerial coil is disposed around the
material rod.
In a tranaponder device designed in this way, because of
the strongly focused axial alignment of the magnetic field
generated by the permeable material rod, a particularly
effective and, consequently, low-loss inductive coupling is
possible between the transponder coil of tire transponder
unit and the aerial coil so that, regardless o~ the
possibility deBCribed above of impedance matching or step-
up transformation of the operating voltage of the
transpvnder unit, this configuration of the transponder
device already makes possible an increase in the operating
Voltage in the transponder unit solely as a result of the
2s particularly low-loss coupling via the material rod.
It proves particularly advantageous that, because of the
particularly low-loss inductive coupling between the aerial
coil and the transponder coil via the material rod) the
configuration described above of the transponder device
makes possible the use of a transponder coil which is
designed as a chip coil disposed on the surface of the
chip. Such chip coils are also known by the team "coil on
chip".
In this connection) in a special embodiment of the
transponder device, the chip is disposed with its rear side
CA 02279176 1999-07-27
on the end face of the permeable material rod) and the chip
coil disposed on the contact side of the chip opposite the
rear side is disposed with its coil surface essentially
congruent with the end face of the material rod. This
results in an extremeJ.y miniaturized transponder device,
such as is used, for example, in an injection tzansponder.
In the method according to the invention of operating a
transponder device havir~g a transponder unit comprising a
chip and a transponder coil and having a transmission
module comprising a coupling coil and an aerial coil
electrically connected to the coupling coil, the impedance
of the aerial coil matched to a reading device
communicating with the transponder unit is converted by
means of the transmission module into an impedance o~ the
coupling coil matched to the impedance of the transponder
unit.
A further method according to the invention of. operating a
transponder device having a transponder unit comprising a
chip and a transponder coil and having a transmission
module comprising a Coupling coil and an aerial coil
electrically connected to the coupling coil consists in
using the Coupling coil of the transmission module together
with the transponder coil as a transformer which increases
the operating voltage in the transponder unit.
Preferred embodiments of the transmission modules according
to the invention and also embodiments of transponder
3o devices provided with such transmission modules axe
explained in greater detail below with respect to the
drawings, possible operating modes of such transponder
devices being explained.
In the drawings.
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Figure 1 shows a diagrammatic view of a data tx-ansmission
arrangement compz~ising a transponder device and a
reading device;
Figure 2 shdwe a detail view of the transponder device
shown diagrammatically in Figure 1;
Figure 3 shows a sectional view of a chip card constructed
in layer technique and provided with a
transponder device;
Figure 4 shows a plan view of the transponder device
- disposed in the chip card shown in Figure 3;
Figure 5 shows a further exemplary embodiment of a
transponder device.
Figure 1 Shows a data transmission arrangement 10
comprising a transponder device 11 and a reading device 12.
The traneponder device 11 comprises a transponder unit 13
and a transmission module 14. In the diagrammatic view
chosen in Figure l, the transponder unit 13 comprises a
chip 15 and a transponder coil 18 electrically connected to
the terminal areas 1~, 17 of the chip 15.
The transmission module 14 comprises in the present case a
coupling element, designed here as coupling coil 19, and an
aerial coil 20 electrically connected to the coupling coil.
The transmission module 14 basically serves to xeceive the
electromagnetic broadcasting power emitted by a
broadcasting coil 21 of the reading device 12 v~.a the
aerial coil 20 and to transmit it inductively by means of
the coupling coil 19 to the transponder coil l8~of the
traneponder unit 13. In this connection, the coupling
coil 19 essentially has the purpose of focusing the
electromagnetic field on the transponder coi1.18 in order
CA 02279176 1999-07-27
to achieve as effective an inductive coupling as possible
between the coupling coil 19 and the transpvnder coil 18.
A further function of the transmission module 14 is to
5 effect an increase in the operating voltage of the chip 15
by means of a suitable interaction with the transponder
coil 18 in order to make possible an increased transmission
distance D between the transpondex device I1 and the
reading device 12.
In addition, the transmission module 14 makes possible a
matching of the impedance ZT of the transponder unit 13 to
the impedance ZL of the reading device 12 as a result of the
fact that the coupling coil 19 arid the aerial coil 20 are
essentially identical in their impedance values to the
transponder unit 13 or the reading device 12, respectively,
or are matched thereto.
Figure 2 shows, for the purpose of a more detailed
explanation of the modes of operation, referred to above,
of the transmission module 14, a more detailed view of the
transponder device 11 with the transponder unit 13
comprising the chip 15 and the transpondex coil 18 and the
transmission module 14 comprising the coupling coil 19 and
the aerial coil 20.
In the present case, the aerial coil 20 comprises a number
of turns n = B and the coupling coil 19 comprises a number
of turns n = 10. The coupling coil 19 and the aerial
coil 20 are connected via electrical conductors 22) 23.
Because of the different winding lengths of the coils in
conjunction with the number of turns, given other~riae
identical coil parameters which influence the coil
impedance of the coupling coil 19 and the aerial~coil 20,
the coupling soil 19 has, in the present case, a lower
impedance than the aerial coil 20. Accordingly) the design
of the transmission module 14 shown in Figure.2 can be
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designed, for example, so that the coupling coil 19 is
matched to the relatively low impedance of the transponder
unit 13 and the aerial coil 20 is matched to the relatively
high impedance of a reading device, which is not shown in
greater detail here) so that it becomes possible by means
of the transmission module 14 to coruzect a high-resistance
reading device to a low-resistance transponder unit without
the transponder unit itself, that is to say the transponder
coil 18, having to be matched directly in terms of
impedance for this purpose.
In the embodiment of the transmission module 14 shown in
Figure 2, in addition, an interaction of the coupling
coil 19 provided with a relatively low number of turns
ri = 10 with the transponder coil 18 comprising a relatively
high number of turns n = 2o produces a transformer effect
via the inductive coupling indicated here by a diagrammatic
field line pattern 24 in such a way that the coupling
coil 19 and the transponder coil 18 act as primary coil and
Zo secondary coil, respectively, of a tran9fonner 25, with the
consequence that a comparatively increased voltage is
induced in the transpvnder coil 18) as a result ox which a
correspondingly increased operating voltage is available
for the chip 15.
Figure 3 shows a transmission module 26 in an embodiment as
a card inlay in a chip card 27 formed in layer technique.
rn addition to the transmission module 26, the further
layers are formed from a chip inlay 28 having a chip 29
accommodated therein, a transponder coil inlay 30 having a
transponder coil 31 embedded therein and in contact with
the chip 29 and two outer top layers 32 and 33.disposed in
each case on the chip inlay 28 or the transmission
module 26. The chip inlay 28 arid the transponder coil
inlay 30 form, in the present case, a transponder
device 49.
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Figure 4 shows the transmission module 26 in a plan view,
with a coupling coil 34 and an aerial coil 35 which are
interconnected via conductors 36) 37 and are disposed here
on a common carrier layer 38 designed as thin-film
substrate, which carrier layer may be composed in the
present case of a polyimide film.
Hoth the transponder coil 31 and the coupling coil 34, and
the aerial coil 35 may be formed as wire coils and also as
coils produced in another way.
Figure 5 shows a transponder device 39 comprising a
transponder unit 40, which is formed from a chip 41 and a
transponder coil 43 disposed directly on the contact
surface 42 provided with terminal areas. In specialist
language, such coil arrangements are also described by the
term ~~coil an chip~~ and can be produced in an etching ox
shearing process.
The transponder device 39 comprises a transmission
module 44 which is compvr~ed of a shoat-circuited aexial
coil 46 disposed around a ferrite core 45. As a departure
from the transmission modules 14 and 26 shown in Figures 2
and 4, the electromagnetic field picked up by the aerial
coil 46 is focused in the case of Ghe transmission
module 44 on the transponder coil 43 not by «<eans of a
coupling coil, but by means of the ferrite core 45 which
strongly focuses the magnetic field and aligns it axially.
As shown in Figure S, the transponder device 39 makes
possible a construction in which the chip 41 can be
positioned by means of its rear side 47 directly on an end
face 48 of the ferrite core 45. To achieve as effective an
inductive coupling as possible between the ferrite core 45
and the transponder coil 43, the chip 41 is disposed on the
end face 4i~ of the ferrite core 45 in such a way that the
end face 48 from which the magnetic field is es$entially
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emitted and the transponder coil 43 are in a congruent
position.
The transponder device shown in Figure 5 is particularly
suitable for use as a so-called injection transponder in
which the transponder device 39 is disposed in a
hermetically sealed manner in an injection container which
is formed, for example, from glass and which can be used,
for example, when subeutaneously injected as transponder
far identifying animals to be slaughtered.