AU4879699A

AU4879699A - A method for producing a contactless chip card

Info

Publication number: AU4879699A
Application number: AU48796/99A
Authority: AU
Inventors: Frank Dorner
Original assignee: Kunz GmbH
Current assignee: Kunz GmbH
Priority date: 1998-09-22
Filing date: 1999-09-20
Publication date: 2000-03-23
Anticipated expiration: 2019-09-20
Also published as: JP2000099680A; AU764706B2; EP0989513A2; EP0989513A3; DE19843425A1

Description

S F Ref: 475538

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

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Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Kunz GmbH Obachgasse A-1220 Wien

AUSTRIA

Frank Dorner Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia A Method for Producing a Contactless Chip Card The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845 r 15657 A method for producing a contactless chip card This invention relates to a method for producing a contactless chip card by laminating a layer structure under pressure and heat which has an inside layer with a recess for Sreceiving at least one chip module and at least one antenna coil and a cover layer on both sides of the inside layer.

To permit the surface to be as smooth and flat as possible the recess in the inside layer in such a chip card is fitted as exactly as possible to the dimensions of the chip iomodule and antenna coil. The inside layer thus generally consists of two single layers. One single layer, in which the annular recess for the antenna coil is punched, has a thickness corresponding to the antenna coil. The remaining part of the chip module, which can have a greater thickness than the tantenna coil from case to case, is received by a further punching possibly in a further single layer (compare e.g.

DE 196 46 184 Al).

In the known chip card production method, single layers must thus be exactly punched, positioned relative to each _Oother and interconnected e.g. thermally before the chip module and coil can be put into the recess.

S"Tolerances of the coil and chip module inevitably result in a more or less wide gap between the recess opening on the surface of the inside layer and the coil or chip module.

For the card thickness to be as small as possible one customarily uses a chip module wherein an IC module is bonded to a thin wafer as a chip carrier. The chip module thus has an irregular thickness cross section, resulting in further free spaces. This causes the formation of hollows on the sur- 3oface of the laminated card which lead to printing errors, i.e. unprinted places, when the card is printed by methods requiring a smooth, flat surface, for example with a thermal printhead.

2 In order to prevent delamination of the card and permit both large- and small-volume antenna windings to be inserted into the recess, it is known from DE 197 10 656 Al to fix a core layer with a recess for the antenna coil and a chip module on an intermediate foil, whereupon the remaining free space is filled with a liquid plastic material and the antenna coil and chip module are then inserted. To obtain a reliable connection of the individual components one places a cut-in intermediate foil on the core layer through which air iO bubbles therebelow can escape. Since the liquid plastic material shrinks when curing, a hollow is also formed on the card surface in this method.

The problem of the invention is to provide a method for obtaining in a simple way chip cards with a perfectly flat and thus correctly printable surface.

This is obtained according to the invention by the method characterized in claim i. The subclaims render advantageous developments of the invention.

According to the inventive method a plastic material 2owhich foams during lamination is introduced into the recess in the inside layer. Thus, the free space of the recess remaining after incorporation of the chip module and/or antenna Coil between the two cover layers is filled with plastic foam, thereby preventing the formation of hollows in the surg face of the card.

According to the inventive method one thus obtains a perfectly smooth card surface which is correctly printable in particular with printing processes using thermal printheads.

The inventively produced card can thus be printed e.g.

2c with a thermal printhead and a thermal transfer band e.g. according to EP 153 693 with a thermoreactive or sublimable ink layer or for example by offset printing without the formation of improperly printed places. This ensures perfect printing, for example during personalization of the card with the card 3 ,owner's name or other data or photo, the value, the period of 3 validity or other alphanumeric data of an identification or key card.

The inside layer and cover layers can be made of any laminable thermoplastic resin, e.g. PVC (polyvinyl chloride), (polyethylene terephthalate), PBT (polybutylene terephthalate), ABS (acrylonitrile-butadiene-styrene), PC (polycarbonate), polyethylene, polypropylene, polyamide or PMMA (polymethylmethacrylate). The inside and cover layers can be made of the same or different plastics.

p The foamable plastic material has a foaming temperature in the range of the laminating temperature or therebelow, i.e. in the range of or below the softening temperature of the plastic of the inside and cover layers.

The foamable plastic material can be for example a mixture of a foaming agent and a prepolymer which cures after foaming, or of a prepolymer with groups from which a gas, such as carbon dioxide, is split off for foam formation during polymerization, for example polyurethane.

According to the inventive method the punching in the in- 0 side layer need not be fitted exactly to the dimensions of the chip module and antenna coil. This considerably simplifies the production of the inside layer. In particular the inside layer can consist according to the invention of a single layer having a thickness corresponding to the height of Sthe chip module. It is thus unnecessary to produce two exactly punched single layers and exactly position and weld the single layers as in the prior art.

One or both of the cover layers can also be constructed of a plurality of single layers which can likewise be inter- 3oconnected during lamination. A plurality of chip modules and/ or antennas can also be provided in one or more recesses in the inside layer.

For incorporation of the foamable plastic material in the recess in the inside layer formed for example by punching, 3~the inside layer is preferably disposed on a cover layer and connected therewith for example by spot welding. The antenna 4 coil together with the chip module bonded thereto is then placed in the recess and at the same time fixed by the foamable plastic material. Then the upper opening of the recess is sealed with the second cover layer, whereupon the layer g assembly is laminated.

It is also possible to dispose the punched inside layer on one cover layer and connect it therewith, then place the chip module with the antenna coil in the recess, and subsequently apply a layer of foamable plastic material to the up- \oper side of the inside layer e.g. with a screen printing apparatus, on which layer the second cover layer is then placed.

For laminating the layers and foaming the foamable plastic in the recess of the inside layer, the thus obtained Ilayer structure can be put into a conventional laminating press with heatable press plates or rolls. The laminating temperature depends on the softening temperature of the plastic of the individual layers of the layer structure and on the foaming temperature of the foamable material. It can be ol130 to 190 0 C for example. To obtain a surface as smooth as possible one can increase the laminating pressure during cooling. It is also possible to press the card in a cold press under elevated pressure after hot laminating. The thus obtained card blank can then be put in the final format of g the card e.g. by punching. The card can then be printed for personalization and the printing optionally provided with a transparent protective layer.

In-the following the inventive method will be explained in more detail with reference to the drawing, in which: S Figure 1 shows a perspective view of the inside layer with a chip module and antenna coil on the lower cover layer before application of the upper cover layer; Figure 2 shows an enlarged cross section through part of the card along line II-II in Figure 1 with the upper cover !layer applied; 5 Figure 3 shows the card according to Figure 2 after foaming of. the plastic material; and Figures 4 and 5 show cross sections of another embodiment corresponding to Figures 2 and 3.

S For producing an identification, credit or similar key card, one fastens inside layer 2 to lower cover layer 1 by spot welding for example. Inside layer 2 has punched recess 4, i.e. opening toward surface 3, which according to Figure 1 consists of annular channel 5 for receiving antenna coil 6 1 •and enlargement 7 of channel 5 for receiving chip module 8 which has IC module 10 bonded to antenna coil 6 on carrier wafer 9.

According to Figure 2 chip module 8 with antenna coil 6 lies on foamable plastic material 12 which has been incorpo- K rated in recess 4 before insertion of module 8 with coil 6.

Second cover layer 13 is placed on surface 3 of inside layer 2 in order to seal recess 4. The thickness of inside layer 2 can be for example 1 mm or less, the thickness of cover layers 1 and 13 e.g. 100 microns or less.

.o The layer structure shown in Figure 2 is disposed for lamination between the two press plates (not shown) of a 00 laminating press. During lamination plastic material 12 is foamed and recess 4 thus filled with plastic foam 12a (Figure 3) In the variant according to Figures 4 and 5, chip module 8 with antenna coil 6 is placed in recess 4 of inside layer 2 to the lower side of which lower cover layer 1 is fastened.

Then layer 15 of foamable plastic material is put on surface 3 of inside layer 2 including recess 4 e.g. with a screen 3 9printing device, whereupon second cover layer 13 is placed on inside layer 2 provided with layer 15. During lamination plastic material 15 is foamed in the area of recess 4, and recess 4 thus filled with plastic foam 15a, while the pressure of the laminating press prevents foaming of layer 15 beinside layer 2 and upper cover layer 13 in the area outside recess 4.

Claims

1. A method for producing a contactless chip card, comprising the steps of: laminating a layer structure having an inside layer with a recess for receiving at least one chip module and/or at least one antenna coil and a cover layer on both sides of the inside layer, under pressure and heat; and incorporating, in the recess, a foamable plastic material which foams during lamination. 1o

2. A method as claimed in claim 1, whereby the inside layer is disposed on a cover layer before the foamable plastic material is incorporated in the recess.

3. A method as claimed in claim 2, whereby the inside layer is connected with one cover layer before incorporation of the foamable plastic material in the recess.

4. A method as claimed in either one of claim 2 or 3, whereby the chip module and/or the antenna coil are placed on the foamable plastic material in the recess.

A method as claimed in any one of claims 1 to 3, whereby the foamable 20 plastic material is applied as a layer to at least one side of the inside layer. too.

6. A method as claimed in claim 1, whereby the inside layer consists of a .6o single layer.

7. A method as claimed in any of the above claims, whereby at least one of the cover layers is printed after lamination.

8. A method for producing a contactless chip card, substantially as described herein with reference to any one of the embodiments, as that embodiment is described in the accompanying drawings. DATED this Thirtieth Day of August, 1999 Kunz GmbH Patent Attorneys for the Applicant SPRUSON FERGUSON [R:\LIBK] 1605.doc:BFD