DE19835965A1 - Identification element - Google Patents

Abstract

The invention relates to an identification element (8) with an integrated circuit (6) and an antenna coil (7) (-> RFID transponder) connected to the integrated circuit (6). DOLLAR A The object of the invention is to propose an inexpensive and reliably working identification element (8). DOLLAR A The object is achieved in that the antenna coil (7) consists of a lower conductor track (1) and an upper conductor track (2), that both conductor tracks (1, 2) each have a plurality of turns (3) that the two conductor tracks (1, 2) are arranged on both sides of a dielectric layer (4) and that the two conductor tracks (1, 2) are positioned relative to one another such that they essentially only in a selected area (5a, 5b) or in two selected areas (5a, 5b) overlap.

Description

The invention relates to an identification element with an integrated circuit circuit and an antenna coil connected to the integrated circuit (→ RFID transponder).

The advantage of RFID transponders over those in particular in the area The barcodes used primarily for goods labeling consist of that they allow a direct exchange of information, d. that is, it is not Visual contact between the interrogation device and transponder for the information Communication required. In addition, it is with RFID transponders in contrast to barcodes, the information content of Change need immediately.

RFID transponders can of course be used in a wide variety of areas Application, especially in the area of manufacturing, further processing work and transportation of goods, also in the field of security applications. Examples include the labeling of people and animals, the labeling of luggage, in particular Airports or at the post office, marking vehicles at the Vehicle manufacturing or in parking garages.  

The disadvantage of the known RFID transponders compared to barcodes is a blatant price difference between the two elements. That is the reason for the fact that RFID transponders are still only used in the sales sector Edge areas are used. In particular, one has so far Provision of price information or other information using RFID Transponders for bulk items in department stores and warehouses distance taken, the cost of an RFID transponder is in the range of 10 DM. Your use as one-way labeling is of course complete out of the question.

RFID transponders are either passive or active elements designed. If the RFID transponder is used as an active element, is in the housing that includes the integrated circuit, an additional Energy source, usually in the form of a battery. RFID Transponders can work in a wide variety of frequency ranges, e.g. B. in the low frequency range at 125 kHz, in the medium frequency range 13.56 MHz or in the microwave range, typically at 2.45 GHz. The present invention preferably relates - but in no way exclusively - on passive transponders in the medium frequency range work.

EP 0 682 321 A2 describes a data carrier with an integrated circuit known. The disk consists of a card body and an integrated circuit that is electrically connected via contact elements at least one coil is connected, which consists of one or more Layers is built up. The elements together form a resonance resonant circuit that operates at a predetermined resonance frequency. The Coil is used for energy supply and / or data exchange integrated circuit with external devices. Circuit and contact elements are designed as separate modules.  

The manufacturing costs of this known embodiment of a transponder are so high that it is only used for products in the higher price ranges can be. It is completely unsuitable for use with mass articles.

A method of contacting an integrated circuit with a Resonant circuit, which is mounted on a flexible carrier, and a Corresponding transponders are described in EP 0 821 406 A1. Of the Resonant circuit is formed from two electrically conductive patterns, which are arranged on both sides of the flexible carrier. The resonance resonant circuit has a certain inductance and a certain capacitance. Around good contact of the integrated circuit with the resonance To ensure the resonant circuit, the contact area on the flexible carrier cleaned. Then the integrated circuit is over a so-called wire connection known from semiconductor technology (wire bonding) connected to the resonant circuit. To prevent the Contacting is destroyed again by external influences integrated circuit and the contacting area with a protective layer overdrawn.

Disadvantages are also with this known method or the known one Transponder the relatively high costs for the individual parts and for the production, it is after contacting the integrated circuit with the Resonant circuit absolutely necessary, the circuit and the To cover the contacting area with a protective layer. Usually transponders are integrated in labels. Since the transponder in the area of Chips is much thicker than in the other areas, this leads to considerable problems when printing in z. B. a thermal Label printer. Furthermore, the resonant circuit forming conductive pattern applied to the carrier by etching. Etchen is a relatively expensive process that also greatly affects the environment charged.  

The invention has for its object an inexpensive and reliable propose working identification element.

The object is achieved in that the antenna coil from a lower Trace and an upper trace is that each trace has one A large number of turns has that the two conductor tracks to both Sides of a dielectric layer are arranged and that the two Conductors are positioned so that they are essentially only in overlap one or two selected areas.

The advantages of the solution according to the invention are, on the one hand, that the Inductance of the antenna coil due to the high number of turns two conductor tracks is relatively high. In particular, it can be measured that the output voltage in a given query field in one predetermined space is sufficient to the integrated circuit activate or operate. On the other hand, the configuration means that the two conductor tracks essentially only in the initial and / or End areas overlap, so that the main contribution to the capacity of the Antenna coil is contributed by these areas while the posts of the remaining overlap areas (i.e. the areas in which the interconnects cross) are negligible. This will make it possible that at the predetermined excitation frequency of the antenna coil higher inductance and thus a higher induced voltage Operation of the integrated circuit can be achieved.

According to an advantageous embodiment, it is provided that the two Antenna coils in one of the two overlap areas, preferably in outer overlap area, electrically connected.

According to an advantageous development of the invention Identification element is provided that it is in the integrated Circuit is a chip without a housing. Of course, this represents a extremely cost-effective solution. Is the identification element in one Integrated label, so printing in z. B. one thermal printer much easier because of the thickness of a transponder without a housing is significantly less than that of a transponder with Casing.  

The conductor tracks are preferably made of a metal foil punched out parts. A process that makes resonance labels very inexpensive Manufacture has already become known from EP 0 655 705 A1. This in Manufacturing processes disclosed in this document are hereby expressly accepted as Disclosure content of the present invention, in particular for manufacturing the antenna coil, added.

According to an advantageous embodiment of the solution according to the invention suggested that the dielectric layer be made of a dielectric adhesive consists. This configuration is also already in the above. European Disclosure described.

The operating voltage of the integrated circuit, i.e. the chip without Housing, is approximately 2 volts. According to an advantageous embodiment of the Identification element according to the invention provides that the number of the turns of the conductor tracks, which are proportional to the inductance of the Antenna coil and therefore the voltage induced, and the size of the Area in which the conductor tracks overlap are chosen so that the Output voltage of the antenna coil for a given query field in a given room range is in the volt range.

In order to compensate for manufacturing tolerances, sees a cheap embodiment of the identification element according to the invention that the antenna coil after completion by heat and pressure in the selected Area or in the selected areas to the desired resonance frequency is tunable. The vote is preferably carried out in that the distance between the two conductor tracks in the overlap area is set by means of a heatable plunger so that the for Activate the integrated circuit required resonance frequency of the antenna coil is supplied. It is quite possible to have one Fine tuning even when the integrated Circuit with the antenna coil is already contacted.

According to a preferred embodiment of the invention Identification element is provided that the antenna coil and integrated circuit via an electrically conductive adhesive connection are interconnected. The adhesive connection is a so-called  isotropic or anisotropic adhesive compounds resulting from the Semiconductor manufacturing are well known. This contacting process is very inexpensive. For the chips used without the housing and the antenna coil described, which is made of punched conductor tracks, it is also easy to use and therefore ideally suited.

An advantageous embodiment of the identification according to the invention elements provides that the two conductor tracks of the antenna coil in have essentially the same dimensions and that the conductor tracks are wound in opposite directions to each other.

Furthermore, the end region of the outer turn and the End region of the inner turn of at least one of the two conductor tracks a wider width than the remaining trace areas. As already stated mentioned earlier, the selected overlap lies areas in these start and / or end areas of the antenna coil. There these areas have a greater width than the other areas of the Conductor tracks, there is a concentration of capacity in the corresponding overlap area. Near the overlap area is also the chip or the integrated circuit with the antenna coil connected. A concentrated total capacity is much cheaper than a total capacity, which is the sum of a large number of individual capacities represents, since the total capacity and thus the energy to operate of the integrated circuit can be concentrated there in a simple manner, where it is needed, namely near the chip.

According to an advantageous embodiment of the invention Identification element is the transponder or the chip between the two inner turns of the two conductor tracks in the area of one Axis of symmetry of the identification element arranged. This The configuration is in particular together with that described below Development of the identification element according to the invention of great Advantage. According to this development, it is provided that between the two traces and outside the area where the chip is arranged, two tracks of a dielectric film are provided. This Foil increases the distance between the two conductor tracks and thus prevents a in the overlap areas of the two conductor tracks  Short circuit occurs that would deactivate the antenna coil. Preferably the dielectric film is made of polyester.

The invention is explained in more detail with reference to the following figures. It shows:

Fig. 1 is a plan view of the lower conducting track,

Fig. 2 is a plan view of the upper wiring,

Fig. 3 is a plan view of an embodiment of the identification element according to the invention and

Fig. 4 is a plan view of a further embodiment of the identification element of the invention.

Fig. 1 shows a plan view of the lower conductor 1, the antenna coil 7. While the lower conductor track 1 has almost three turns 3 , the upper conductor track 2 - as can be seen from the plan view in FIG. 2 - has almost four turns 3 . The relatively high number of turns results in a high inductance and ultimately the provision of a sufficiently high induced voltage for activating the integrated circuit 6 . Incidentally, the two conductor tracks 1 , 2 are wound in opposite directions.

Fig. 3 shows the way the finished identification element 8, which is composed of the two tracks 1, 2.

The start area 5 and the end area 5 of the lower conductor track 1 and the end area of the upper conductor track 2 have a greater width than the other areas of the conductor tracks 2 , 3 . Both conductor tracks 1 , 2 are preferably punched out of a metal foil, in particular an aluminum foil. Of course, the film could also be made of another conductive metal, e.g. B. made of copper.

For the purpose of forming the antenna coil 7 , a dielectric layer 4 is arranged between the two conductor tracks 1 , 2 . The two conductor tracks 1 , 2 are positioned in relation to one another such that they overlap essentially only in selected areas 5 a, 5 b. According to a preferred embodiment, the two conductor tracks 1 , 2 are electrically contacted with one another in the overlap region 5 b of the outer turns 3 . In the simplest case, the contact is made by punching the two conductor tracks in the overlap area 5 b. However, other methods of contacting can also be used.

The dielectric layer 4 , which is arranged between the two conductor tracks 1 , 2 , is preferably a dielectric hot-melt adhesive. The dielectric layer 4 electrically isolates the two conductor tracks 1 , 2 from one another. The offset positioning of the two conductor tracks 1 , 2 ensures that the majority of the capacitance comes from the overlap regions 5 , while the other overlap regions 10 , in which the two conductor tracks 1 , 2 intersect, only make insignificant contributions to the total capacity. This configuration concentrates the capacity and thus the energy of the antenna coil in the area in which it is needed, namely in the immediate vicinity of the chip.

The integrated circuit 6 , that is to say the preferably unpackaged chip 6 , is arranged between the end region of the lower interconnect 1 and the end region of the upper interconnect 2 in the immediate vicinity of the central axis 11 of the antenna coil 6 .

The contact between chip 6 and conductor tracks 1 , 2 is preferably carried out by means of the so-called flip-chip bonding method, that is to say using an electrically conductive adhesive. Of course, the other contacting methods that have become known from semiconductor production can also be used in connection with the present invention.

In order to prevent that a short circuit occurs in the overlapping portions 11, which would deactivate the antenna coil 7 and the identification member 8 is provided at least in these regions 11 an additional dielectric film 9 or other additional dielectric layer.

In FIG. 4, a further embodiment can be seen of the identification element of the invention. 8 It differs from the identification element 8 shown in the previous figures only in design.

Reference list

1

lower trace

2nd

upper trace

3rd

Swirl

4th

dielectric layer

5

a Overlap area / end area

5

b Overlap area / end area

6

integrated circuit

7

Antenna coil

8th

Identification element

9

dielectric film

10th

Overlap area

11

middle axis

Claims (14)

1. Identification element with an integrated circuit and an antenna coil connected to the integrated circuit (→ RFID transponder), characterized in that
that the antenna coil ( 7 ) consists of a lower conductor track ( 1 ) and an upper conductor track ( 2 ),
that both conductor tracks ( 1 , 2 ) each have a plurality of turns ( 3 ),
that a dielectric layer ( 4 ) is arranged between the two conductor tracks ( 1 , 2 ) and
that the two conductor tracks ( 1 , 2 ) are positioned so that they overlap essentially only in a selected area ( 5 a; 5 b) or in two selected areas ( 5 a, 5 b). 2. Identification element according to claim 1, characterized in that the integrated circuit is a chip ( 6 ) without a housing. 3. Identification element according to claim 1 or 2, characterized in that the antenna coil ( 7 ) and the integrated circuit ( 6 ) are connected to one another via an electrically conductive adhesive connection. 4. Identification element according to claim 1, characterized in that the conductor tracks ( 1 , 2 ) are parts punched out of a metal foil. 5. Identification element according to claim 1, characterized in that the dielectric layer ( 4 ) consists of a dielectric adhesive. 6. Identification element according to claim 1, 2, 3, 4 or 5, characterized in that the number of turns ( 3 ) of the conductor tracks ( 1 , 2 ), which determines the inductance of the antenna coil ( 7 ), and the size of the area ( 5 ), in which the conductor tracks ( 1 , 2 ) overlap, are selected such that the output voltage of the antenna coil ( 7 ) lies in a predetermined spatial area in the volt range for a given query field. 7. Identification element according to claim 1 or 6, characterized in that the antenna coil ( 7 ) after completion by heat and pressure in the selected area ( 5 a; 5 b) or in the selected areas ( 5 a, 5 b) the desired resonance frequency can be tuned. 8. Identification element according to one or more of the preceding claims, characterized in that
that the two conductor tracks ( 1 , 2 ) of the antenna coil ( 7 ) have essentially the same dimensions and
that the conductor tracks ( 1 , 2 ) are wound in opposite directions to each other. 9. Identification element according to claim 1 or 7, characterized in that the end region ( 5 b) of the outer turn ( 3 ) and the end region ( 5 a) of the inner turn ( 3 ) of at least one of the two conductor tracks ( 1 ; 2 ) one has a greater width than the remaining areas of the corresponding conductor track ( 1 ; 2 ). 10. Identification element according to claim 1 or 9, characterized in that the two conductor tracks ( 1 , 2 ) in the end regions ( 5 b) of the two outer turns ( 3 ) are electrically connected to one another. 11. Identification element according to claim 1 or 10, characterized in that the transponder ( 6 ) or the chip ( 6 ) between the two inner turns ( 3 ) of the two conductor tracks ( 1 , 2 ) in the region of a central axis ( 11 ) of the Identification element ( 8 ) is arranged. 12. Identification element according to one or more of the preceding claims, characterized in that an additional dielectric layer ( 9 ) is provided between the two conductor tracks ( 1 , 2 ) and outside the area in which the chip ( 6 ) is arranged. 13. Identification element according to claim 12, characterized in that the dielectric layer is two webs ( 9 ) of a dielectric film, which are preferably made of polyester. 14. Antenna coil for use in an identification element with an integrated circuit, characterized in that
that the antenna coil ( 7 ) consists of a lower conductor track ( 1 ) and an upper conductor track ( 2 ),
that both conductor tracks ( 1 , 2 ) each have a plurality of turns ( 3 ),
that a dielectric layer ( 4 ) is arranged between the two conductor tracks ( 1 , 2 ) and
that the two conductor tracks ( 1 , 2 ) are positioned so that they overlap essentially only in a selected area ( 5 a; 5 b) or in two selected areas ( 5 a, 5 b).