Registers – Records – Laminated
Reexamination Certificate
1999-05-11
2001-01-16
Le, Thien M. (Department: 2876)
Registers
Records
Laminated
C235S492000, C257S679000
Reexamination Certificate
active
06173898
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to memory cards of the contactless type. Such cards are commonly used as identity badges or remote payment cards, for example.
BACKGROUND OF THE INVENTION
As a general rule, contactless memory cards comprise an integrated circuit associated with a coupling antenna, both of which are embedded in a flat insulating assembly. In practice, the antenna is arranged in a spiral pattern, with its two ends being connected to two contact pads of the integrated circuit.
Document EP-A-0 671 705 illustrates a contactless card having a card body with a cavity leaving the contact terminals of the coupling antenna visible. Into the cavity is inserted an electronic module that comprises an integrated circuit with two contact areas.
A contactless card of that type has the drawback that it is necessary to form a cavity in the card body, and that the electronic module must be placed as accurately as possible in position in the associated cavity in each card body. Such a process is difficult to make compatible with mass production of contactless cards.
The invention relates more particularly to a contactless memory card of the type comprising a laminated card body of plastic material having a support sheet that is sandwiched between other sheets, or layers, and that has on one face thereof both a coupling antenna and an integrated circuit whose two contact pads are connected to the coupling antenna.
Document EP-A-0 737 935 illustrates a contactless card of that type. The integrated circuit of the contactless card described in that document is associated with the coupling antenna via a layer of anisotropic conductive adhesive material that is about 10 &mgr;m to 50 &mgr;m thick. The contact pads of the integrated circuit are then embedded in the anisotropic conductive adhesive layer. The mechanical connection between the integrated circuit and the insulating support sheet can nevertheless be too weak, insofar as the adhesive layer adheres only to the top faces of the turns of the coupling antenna. Consequently, the mechanical retention of the integrated circuit on the contact areas of the coupling antenna can be insufficient in the event of bending and/or twisting forces being imparted to the laminated card body of the contactless memory card.
Reference can also be made to documents DE-A-4 31 605 and EP-A-0 682 321 which show other arrangements that are analogous.
SUMMARY OF THE INVENTION
One object of the invention is to provide a contactless memory card having a card body made of laminated plastic material, in which the integrated circuit has better mechanical adhesion to the contact areas of the coupling antenna, even when large bending or twisting forces are applied.
Another object of the invention is to provide a contactless type memory card in which the structure is compatible with making a coupling antenna by silk screen printing on the associated support sheet.
These and other objects are attained in accordance with one aspect of the present invention directed to a memory card of the contactless type, comprising a laminated card body of plastic material presenting a sandwiched support sheet having on one face thereof a coupling antenna and an integrated circuit with two contact pads connected to the coupling antenna. The integrated circuit rests via the two pads directly on two conductive areas connected to the coupling antenna, and it also rests on at least one additional compensation area that is not connected to the antenna, so that the integrated circuit extends, or lies, substantially parallel to the support sheet. The integrated circuit and the support sheet are mechanically connected to each other by an adhesive material arranged in the empty space defined by their respective facing faces.
The adhesive material present in the empty space defined by the respective facing faces of the integrated circuit and of the support sheet imparts much greater mechanical strength than that encountered with contactless cards of the prior art.
Preferably, two connected conductive areas and two non-connected compensation areas are provided occupying two diagonals of a rectangle to enable the integrated circuit to be supported directly via its four corners. In particular, turns of the coupling antenna pass between pairs of adjacent areas by extending under the integrated circuit.
According to another highly advantageous characteristic of the invention, the adhesive material comprises one or two spots of adhesive, and a sealing resin occupying the majority of the empty space defined by the respective facing faces of the support sheet and of the integrated circuit. The above-mentioned sealing resin considerably improves the mechanical strength of the assembly. If so desired, this makes it possible to silk screen print the coupling antenna on the support sheet and to provide larger track widths for the connections between the integrated circuit and the silk screen printed contact areas.
At least one of the turns of the coupling antenna passing beneath the integrated circuit preferably presents an external portion extending out from under the integrated circuit. In particular, two turns of the coupling antenna present profiles that correspond in axial symmetry about a center substantially in registration with the center of the integrated circuit, and the external portions of the two turns form two arcs whose concave sides face toward the center of symmetry. Each of the above-mentioned arcs enables a deposited drop of sealing resin to be confined within the concave side thereof, such drops then extending by capillary action into the empty space defined by the respective facing faces of the support sheet and of the integrated circuits.
In a particular embodiment, provision can be made for the non-connected compensation areas to present respective retaining appendices extending toward an adjacent turn of the coupling antenna passing beneath the integrated circuit. These appendices make it possible to form a throat while the liquid resin is flowing beneath the integrated circuit, thereby improving retention and expansion of the liquid resin.
The invention also provides a method of manufacturing a memory card of the above-specified type, such method being remarkable in that prior to laminating the card body, the following successive steps are performed:
a) a coupling antenna, two conductive areas connected to said coupling antenna, and two non-connected compensation areas are formed on one face of the insulating support sheet by etching or by printing, said areas being positioned in a rectangle corresponding to the format of the integrated circuit to be put into place; and
b) the integrated circuit is put into place so that two of its pads bear directly on the conductive areas and an adhesive material is interposed in the empty space defined by the facing faces of the support sheet and of the integrated circuit.
Preferably, the adhesive material is interposed firstly by forming one or two spots of adhesive to provide a mechanical link between the support sheet and the integrated circuit, and then depositing at least one drop of sealing resin in the fluid state on the support sheet in the vicinity of the integrated circuit, said drop extending by capillary action into the empty space defined by the respective facing faces.
In the particular case of turns having arcs with their concave sides directed toward the center of symmetry, it is possible to provide for a spot of sealing resin to be deposited within the concave side of each of the arcs.
REFERENCES:
patent: 5400950 (1995-03-01), Myers et al.
patent: 5448110 (1995-09-01), Tuttle et al.
patent: 5598032 (1997-01-01), Fidalgo
patent: 5705852 (1998-01-01), Orihara et al.
patent: 5852289 (1998-12-01), Masahiko
patent: 44 31 605 (1996-03-01), None
patent: 0 645 806 (1995-03-01), None
patent: 0 671 705 (1995-09-01), None
patent: 0 682 321 (1995-11-01), None
patent: 0 737 935 (1996-10-01), None
patent: WO 96/37913 (1996-11-01), None
Frishauf, Holtz Goodman, Langer & Chick, P.C.
Le Thien M.
Lee Diane I.
Schlumberger Systemes
LandOfFree
Memory card of the contactless type does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Memory card of the contactless type, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Memory card of the contactless type will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2451060