Registers – Records – Laminated
Reexamination Certificate
1997-07-08
2001-03-27
Le, Thien M. (Department: 2876)
Registers
Records
Laminated
C235S492000
Reexamination Certificate
active
06206291
ABSTRACT:
FIELD OF THE INVENTION
The present invention concerns electronic cards incorporating at least one electronic element.
In particular, a card according to the invention comprises an integrated circuit serving for example for the identification of persons.
BACKGROUND OF THE INVENTION
A category of electronic cards concerned by the invention is made up by cards without exterior electrical contact and possessing a coil enabling electromagnetic coupling with an external arrangement.
By card is understood every object having a substantially planar structure defining a general plane of the object and exhibiting any contour whatsoever in such general plane.
The patent document EP 0 570 784 in the name of the present applicant describes various embodiments of an electronic card comprising a layer formed by a solidified binder in which is incorporated at least one electronic element electrically coupled to a coil. This document also describes various embodiments of a method of manufacture of such a card.
In a particularly advantageous embodiment, there is provided a positioning structure exhibiting at least one principal opening in which is housed the electronic element. In each embodiment described, the coil and the electronic element are housed within such principal opening. In all the proposed embodiments, the various elements incorporated within the solidified layer of binder are located facing entirely planar surfaces.
According to an embodiment of the method of manufacture described in the patent document EP 0 570 784, the following various steps for the manufacture of a card are provided:
I) the bringing onto a work surface of a first outer layer formed from a solid material;
II) the placing of at least one electronic element on the first outer layer;
III) the bringing of a binder onto the first outer layer;
IV) the bringing onto said binder of a second outer layer formed from a solid material and facing the first outer layer;
V) the application of a pressure on the first and second outer layers until such outer layers are located at a predetermined distance relative to one another.
In a final step, the binder is solidified in order to form an intermediate layer between the outer layers.
According to a specific characteristic of the method described hereinbefore, a positioning structure, defining at least one internal zone serving in particular for positioning the coil, is brought in between steps I and IV of the method.
According to a variant of the method described hereinbefore, it is foreseen to bring initially the planar outer layer and the various elements to be incorporated into the card, in particular the electronic element electrically coupled to the coil and also a positioning structure when the latter is provided. Next, the binder is applied in the form of a viscous liquid. Onto such binder is then applied the second outer layer. Finally, with the help of pressing means, pressure is exerted on the outer layers and consequently on the binder along a direction perpendicular to the work surface so as to form the layer of binder in which are incorporated various elements as provided.
The variant of the method described hereinbefore is very advantageous from an economic viewpoint since it enables producing large quantities of cards at low cost. Additionally, such variant is advantageous from the fact that it does not necessitate applying heat in order to melt the outer layers, thus avoiding the shrinkage phenomena of the material and buckling of the card once cooled. However, the applicant has observed in the course of numerous experiments that the method described hereinbefore brings results which are satisfactory for various specific embodiments, but that on the other hand a certain number of cards obtained by this method and having one of the structures proposed in patent document EP 0 570 784 does not exhibit a sufficiently satisfactory flatness such that for certain embodiments the industrial yield is relatively low.
Effectively, the requirement of flatness for electronic cards is particularly high, in particular when printing is provided on an external surface of such cards. Certain printing techniques require absolutely planar outer surfaces, lacking which deformations appear in the printed message.
SUMMARY OF THE INVENTION
The purpose of the present invention is to overcome the drawbacks remaining in the invention described in patent document EP 0 570 784 in providing an electronic card exhibiting very good flatness and no residual air in the binder layer, such card also being obtainable with the help of a relatively simple method.
Here it should be mentioned that the applicant has carried out extensive research on the cards produced according to the method described hereinbefore in order to detect the nature of the problem causing deformations in the surface of a certain number of cards. During such research, the applicant has initially determined that in a certain number of applications the coil occupied a relatively large surface as projected into the general plane of the card. Next, and in contrast to the coils as shown drawn on the figures of patent document EP 0 570 784, the coils used in electronic cards generally exhibit a cross-section of rectangular form. Additionally, such coils are self-supporting, that is to say, the windings of such coils are glued to one another. Thus, the coil exhibits a definite form and a certain rigidity.
In the variant of the method described hereinbefore, when the coil is applied to the first planar outer layer, the lower surface of such coil then bears against the inner face of such first outer layer. When the binder is applied in the form of a viscous liquid and pressure is exerted on the latter, the binder spreads out and covers the upper surface of the coil, which generates a resultant pressure on such coil towards the work surface. The coil is thus pressed against the first outer layer and the binder does not infiltrate between the coil and such first outer layer. Thereby, the first outer layer does not adhere to the layer of binder on its superposition surface with the coil, which can bring about deformations on the surface of the first outer layer following solidification of the binder and removal of the pressure exerted on the latter.
The above-mentioned problem is further aggravated by a second problem connected with the state of the lower surface of the coil. Effectively, the coil is formed from windings exhibiting a circular cross-section. The coils are formed with the help of a winding arrangement generally exhibiting two flanges between which the coil is formed. Inevitably, the surfaces of the coil exhibit a multitude of furrows, certain of which may have a depth which is not negligible. Once the coil is brought onto the inner face of the outer layer, the furrows located on the lower surface of the coil define at least one substantially closed space between the coil and the outer layer, resulting in a confinement of air during formation of the card. Such residual air can be slightly pressurized during the application of pressure on the binder serving to form the binder layer which brings about deformations of the outer face of the outer layer when application of the pressure has ceased. Additionally, it has been observed that when said pressure is removed, the residual air confined between the coil and the outer layer is apt to diffuse within the card and in particular at the interface between the outer layer initially supplied and the layer of binder.
It will be mentioned that similar problems appear with other elements incorporated in an electronic card, in particular when a substrate is provided on which the electronic element is secured, such as that described on
FIGS. 10 and 11
of patent document EP 0 570 784. Such problems can also be encountered with other elements incorporated in the card, for example with an electronic unit of a certain dimension exhibiting a planar face or a protection ring on the interior of which is housed an integrated circuit for example.
In order to achieve the purpose of the inventi
Griffin & Szipl, P.C.
Le Thien M.
NagraID S.A.
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