U.S. patent application number 15/676588 was filed with the patent office on 2017-11-30 for plastic layer for a smart card.
This patent application is currently assigned to Nagravision S.A.. The applicant listed for this patent is Nagravision S.A.. Invention is credited to Francois DROZ.
Application Number | 20170341290 15/676588 |
Document ID | / |
Family ID | 47900523 |
Filed Date | 2017-11-30 |
United States Patent
Application |
20170341290 |
Kind Code |
A1 |
DROZ; Francois |
November 30, 2017 |
PLASTIC LAYER FOR A SMART CARD
Abstract
A plastic sheet for manufacturing of a plurality of smart cards
which respectively include a plurality of electronic units,
includes a first sheet formed of a first material having a first
hardness or a first Vicat softening temperature, the first sheet
including a plurality of apertures and/or cavities. The plastic
sheet includes a second material having, when the first material
has the first hardness, a second hardness lower than the first
hardness, and when the first material has the first Vicat softening
temperature, a second Vicat softening temperature lower than the
first Vicat softening temperature, the second material being
located inside the apertures and/or cavities in the first sheet.
The apertures and/or cavities with the second material located
inside the apertures and/or cavities are configured to respectively
receive said electronic units via an at least partial penetration
from the electronic units into the second material.
Inventors: |
DROZ; Francois; (Corcelles,
CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nagravision S.A. |
Cheseaux-sur-Lausanne |
|
CH |
|
|
Assignee: |
Nagravision S.A.
Cheseaux-sur-Lausanne
CH
|
Family ID: |
47900523 |
Appl. No.: |
15/676588 |
Filed: |
August 14, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14177848 |
Feb 11, 2014 |
|
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15676588 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y10T 428/24273 20150115;
G06K 19/07718 20130101; Y10T 428/24479 20150115; G06K 19/07745
20130101; B32B 3/266 20130101; G06K 19/07722 20130101; B29C 51/12
20130101 |
International
Class: |
B29C 51/12 20060101
B29C051/12; G06K 19/077 20060101 G06K019/077 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 18, 2013 |
EP |
13155635.9 |
Claims
1. A plastic sheet for manufacturing of a plurality of smart cards
which respectively include a plurality of electronic units,
comprising: a first sheet formed of a first material having a first
hardness or a first Vicat softening temperature, the first sheet
including a plurality of apertures and/or cavities; and a second
material having, when the first material has the first hardness, a
second hardness lower than the first hardness, and when the first
material has the first Vicat softening temperature, a second Vicat
softening temperature lower than the first Vicat softening
temperature, the second material being located inside the plurality
of apertures and/or cavities in the first sheet, wherein the
plurality of apertures and/or cavities with the second material
located inside the plurality of apertures and/or cavities are
configured to respectively receive said plurality of electronic
units via an at least partial penetration from the plurality of
electronic units into the second material.
2. The plastic sheet according to claim 1, wherein said second
Vicat softening temperature under a load of 10 N is lower than
fifty degrees.
3. The plastic sheet according to claim 1, wherein said second
hardness is less than 96 Shore A.
4. The plastic sheet according claim 1, wherein said first Vicat
softening temperature under a load of 10 N is lower than sixty-five
degrees.
5. The plastic sheet according to claim 1, wherein said first
hardness is more than 60 Shore D.
6. The plastic sheet according to claim 1, wherein said second
material is formed by a thermoplastic polyurethane elastomer.
7. The plastic sheet according to claim 1, wherein said first
material forms the first sheet having the plurality of apertures at
least partially filled by said second material.
8. The plastic sheet according to claim 1, wherein said first
material forms the first sheet having the plurality of cavities at
least partially filled by said second material.
9. The plastic sheet according to claim 1, wherein the second
material that is located inside the plurality of apertures and/or
cavities is substantially flush with a face of the plastic sheet in
which the plurality of apertures and/or cavities are formed.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/177,848, filed Feb. 11, 2014, and claims
priority from European Patent Application No. 13155635.9, filed
Feb. 18, 2013. The entire contents of each of the above
applications are hereby incorporated by reference herein in
entirety.
FIELD OF THE INVENTION
[0002] The present invention concerns the field of smart cards
incorporating at least one electronic unit, in particular an
integrated circuit, inside the card body. In particular, the
invention concerns plastic materials forming the card body. The
invention also concerns a method of fabricating a plastic layer
intended to receive a plurality of electronic units during the
formation of a plurality of cards.
BACKGROUND OF THE INVENTION
[0003] There is known, in particular from EP Patent No 1846874, a
smart card fabrication method wherein an assembly formed of an
integrated circuit and conductive segments is placed on a substrate
and at least one integrated circuit is introduced into the
substrate. Several variants are proposed. In a first variant, the
integrated circuit is pushed straight into the material forming the
substrate, the latter being relatively hard since it has conductive
paths on its surface. Penetration into the material is generally
achieved by using heat to soften the substrate material at least
locally. In a second variant, prior to inserting the integrated
circuit, a housing is arranged in the substrate having dimensions
which substantially match those of the integrated circuit or are
slightly different therefrom. In a third variant, a housing is
formed having larger dimensions than those of the integrated
circuit and an adhesive substance is deposited in the housing,
prior to adding the integrated circuit assembly and conductive
segments; then a fitting device presses the integrated circuit into
the adhesive substance which is spread out and pushed back into the
space located between the integrated circuit and the wall of the
housing.
[0004] Although possible to achieve, each of the variants described
above has a drawback. The first variant faces the fact that the
substrate is generally formed by a relatively hard plastic layer;
which requires particular precautions during fabrication of smart
cards and particularly requires the areas penetrated by the
integrated circuits to be at least locally softened, to avoid
damaging the integrated circuits. Further, once the card is
finished, the integrated circuit is surrounded by a relatively hard
material; which may cause excessive mechanical stresses on the
integrated circuit during use of the card, in particular when the
card is subject to bending or twisting. In addition to the last
mentioned problem of the first variant, the second variant raises a
fabrication problem since it requires high precision positioning of
the integrated circuit relative to the housing prior to insertion
therein. This is possible to achieve with available fabrication
plants, but the production of smart cards is then more expensive.
The third variant may overcome certain of the aforementioned
problems, but it requires the localised administration of drops of
resin in the substrate housings in the smart card fabrication
site.
SUMMARY OF THE INVENTION
[0005] It is an object of the present invention to overcome the
aforementioned prior art problems and to improve the smart card
fabrication method.
[0006] The present invention therefore concerns a plastic sheet
involved in the formation of a plurality of smart cards which
respectively include a plurality of electronic units. This plastic
sheet is formed of a first material, having a first hardness or a
first Vicat softening temperature, and of a second material having
a second hardness lower than the first hardness, respectively a
second Vicat softening temperature lower than the first Vicat
softening temperature. The second material is located in a
plurality of areas of the plastic sheet which are respectively
intended to at least partially receive the plurality of electronic
units, via penetration into the second material.
[0007] The present invention also concerns a method of fabricating
a plastic sheet according to the invention, which will be described
below in the detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The invention will be described below with reference to the
annexed drawings, given by way of non-limiting example, and in
which:
[0009] FIG. 1 is a schematic view of a step of the method of the
invention for fabricating a bimaterial plastic sheet.
[0010] FIGS. 2 to 3 are schematic cross-sections of a next step of
the fabrication method according to the invention.
[0011] FIG. 4 shows a schematic cross-section of a first embodiment
of a bimaterial plastic sheet according to the invention.
[0012] FIG. 5 is a schematic view of a second embodiment of a
bimaterial plastic sheet according to the invention.
[0013] FIG. 6 is a schematic view of a third embodiment of a
bimaterial plastic sheet according to the invention.
[0014] FIG. 7 is a schematic top view of a fourth embodiment of a
bimaterial plastic sheet according to the invention.
[0015] FIG. 8 is a schematic view of one use of a bimaterial sheet
according to the invention in a first smart card fabrication
method.
[0016] FIG. 9 shows an intermediate product occurring in the first
smart card fabrication method and resulting from the step described
in FIG. 8.
[0017] FIG. 10 is a schematic view of one use of a bimaterial sheet
according to the invention in a second smart card fabrication
method.
[0018] FIG. 11 shows an intermediate product occurring in the
second smart card fabrication method and resulting from the step
described in FIG. 10.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Firstly, a method will be described for fabricating a
plastic sheet involved in the formation of a plurality of smart
cards which respectively include a plurality of electronic units.
This plastic sheet is intended to at least partially receive the
plurality of electronic units by penetrating the material forming
the units, as will be explained below.
[0020] According to the invention, the method of fabricating a
plastic sheet including the following steps:
[0021] A) Taking a first sheet 2 formed of a first material having
a first hardness or a first Vicat softening temperature, said first
sheet having a plurality of apertures 4 (see FIG. 1);
[0022] B) Respectively placing in said plurality of apertures 4 a
plurality of discs 6 formed of a second material having a second
hardness lower than the first hardness, respectively a second Vicat
softening temperature lower than the first Vicat softening
temperature (see FIGS. 1 and 2; it will be noted that, for the sake
of clarity of the drawing, FIG. 1 only shows the discs provided for
one row of apertures).
[0023] In a variant, the first sheet has a plurality of cavities
(blind holes) and the discs are placed in said plurality of
cavities. In another variant, the first sheet has apertures (which
traverse the first sheet) and cavities which receive all the discs
formed of a second material, these apertures and cavities being
arranged to receive first and second electronic units
respectively.
[0024] In the geometric plane parallel to general plane 10 of the
first sheet 2, the plurality of discs 6, provided in the
aforementioned step B), have smaller dimensions than those of the
corresponding apertures 4 and/or cavities and a greater height H,
along an axis perpendicular to said general plane, than that of the
corresponding apertures and/or cavities, so that they rise above a
face 8 of the first sheet. For circular discs, it is the diameter D
of these circular discs which will be smaller than the diameter of
the corresponding apertures 4 and/or cavities. For rectangular
discs, the smaller dimensions are of course the width and length of
the rectangular discs. Other disc geometries may be provided in
general plane 10 in other variants.
[0025] Preferably, the first sheet 2 and discs 6 are placed on a
support 12 having a top layer 14 which is non-adherent to the first
sheet and the discs. The top layer 14 is for example formed of
Teflon.RTM.. Support 12 for example forms part of a press 16 shown
schematically in FIG. 2.
[0026] Following the insertion of each disc 6 in a corresponding
aperture 4 or cavity, the following step is provided for the
disc:
[0027] C) Exerting a pressure on disc 6 to reduce the height
thereof so that the disc is substantially flush with face 8 of
first sheet 2 and is at least partially in contact with lateral
wall 20 of the corresponding aperture or cavity, disc 6 then being
connected to the first sheet.
[0028] In a first implementation shown in FIG. 3, step C) is
performed using laminating press 16. The bottom surface of the top
part of the press is advantageously formed by a layer of
Teflon.RTM. 18. It will be noted that layers 14 and 18 may be
replaced by non-adherent sheets which are removable. In a preferred
implementation, step C) consists of a hot lamination, the plurality
of discs 6 being at least partially welded to the first sheet 2.
Press 16 then includes a heating means. In this first
implementation, the set of discs is placed in the corresponding
apertures and then the aforementioned step C) is simultaneously
performed for the plurality of discs. In a second implementation
not shown in the Figures, steps B) and C) are performed cyclically
for each disc or for subsets of discs among the plurality of discs.
In a first variant, each disc is individually placed in the
corresponding aperture using a tool. Next, a thermode is
individually applied to the disc to perform step C); and these two
steps are repeated with the following disc.
[0029] Preferably, the dimensions of the thermode are slightly
larger than those of the apertures. The thermode thus covers the
aperture and a peripheral area of the aperture when a disc inserted
into the aperture is pushed in. This can thus be termed a localised
lamination. In a particular variant, the first tool and the
thermode form one and the same tool and step C) immediately follows
step B) for each disc. In a second variant, a first subset of discs
is placed in a first subset of corresponding apertures. Next,
several thermodes are respectively placed on the subset of discs
and step C) of the method is simultaneously performed for the
subset of discs. The subset of apertures is, for example, a line or
a column of apertures in a first sheet having a matrix of
apertures.
[0030] A first embodiment of a bimaterial plastic sheet 22
according to the invention, obtained notably via the fabrication
method described above, is shown in cross-section in FIG. 4. This
plastic sheet is formed of a first sheet 2 formed of a first
material, having a first hardness. This first sheet 2 has a
plurality of apertures which are filled by discs 6 formed of a
second material having a second hardness, lower than the
aforementioned first hardness. The second material adheres to the
lateral wall 20 of the holes. The plurality of apertures 4 defines
a plurality of areas 5 of the plastic sheet 22 in which the second
material is located. This plurality of areas of lower hardness is
respectively intended to receive a plurality of electronic units
via penetration of the second material, as will be explained
below.
[0031] In a first variant, the second hardness is less than 96
Shore A. In a second variant, the first hardness is more than 60
Shore D. In a particular embodiment, the first and second variants
are advantageously combined. Preferably, the second material is
formed by a thermoplastic polyurethane elastomer. For the
definition of Shore A and Shore D, reference may be made to ISO
standard 868 and DIN standard 53505 respectively. Thermoplastic
polyurethane elastomers are sold, in particular, by BASF under the
name Elastollan.RTM..
[0032] In an alternative of the invention, the plastic sheet
according to the invention is formed of a first material 2, having
a first Vicat softening temperature, and of a second material 6
having a second Vicat softening temperature, which is lower than
the first Vicat softening temperature. In a first variant, the
second Vicat softening temperature under a load of 10 N is less
than fifty degrees (50.degree. C.). In a second variant, the first
Vicat softening temperature under a load of 10 N is more than
sixty-five degrees (65.degree. C.). In a particular embodiment, the
first and second variants are advantageously combined. Preferably,
the second material is formed by a thermoplastic polyurethane
elastomer. The Vicat softening temperature is the temperature
measurement at which a pin with a section of 1 mm.sup.2 penetrates
a thermoplastic material to a depth of 1 mm tested under a load of
10 N or 50 N (for further information, reference may be made to ISO
306). The various embodiments of the plastic sheet of the invention
also apply to this alternative.
[0033] A second embodiment of a bimaterial plastic sheet 24
according to the invention is shown in cross-section in FIG. 5.
This plastic sheet 24 differs from the first embodiment in that it
is formed of a first sheet 2A formed of said first material and
having a plurality of cavities 26 filled with discs 6A formed of
said second material. The plurality of cavities 26 open out on the
top face 8 of plastic sheet 24 and define a plurality of areas 5A
in which the second material is located. This plurality of areas of
lower hardness is respectively intended to receive a plurality of
electronic units via penetration of the second material, as will be
explained below. It will be noted that, in a variant embodiment,
the first sheet 2A is formed by two layers 28 and 29, layer 28
having a plurality of holes whereas layer 29 is continuous and
defines the bottom of cavities 26. Layers 28 and 29 may be welded
or bonded in a preliminary step prior to the insertion of the
plurality of discs 6A. Preferably, they are welded during step C)
of the fabrication method described above, simultaneously as discs
6A are pushed in and welded to first sheet 2A.
[0034] It will be noted that, in a variant, discs 6 or 6A may be
respectively bonded inside apertures 4 or cavities 26. In another
variant, the second material is introduced into apertures 4 or
cavities 26 by a technique of injecting or casting said second
material.
[0035] A third embodiment of a bimaterial plastic sheet 32
according to the invention is shown in cross-section in FIG. 6. The
third embodiment differs from the preceding embodiments in that the
plurality of apertures 4B in first sheet 2B each has an annular
shoulder 34 in the bottom part thereof. Discs 6B have an initial
diameter such that they abut against the lateral walls 20B of the
respective shoulders 34 during the pushing in which occurs in step
C) of the fabrication method described above, without however
filling the annular areas 35 located above the annular shoulders.
Discs 6B define, on the top face 8 of plastic sheet 32, areas 5B of
lower hardness having a smaller diameter than that of the
respective apertures 4B. The space remaining in each annular area
35 is advantageous for the subsequent penetration of an electronic
unit, in particular when the unit has relatively large dimensions
and the second material forming discs 6B is not compressible.
Finally, it will be noted that, as in the second embodiment, the
first sheet 2B is formed in a preferred variant of two layers 36
and 37, respectively having a first plurality of holes and a second
plurality of holes, the latter having smaller diameters than those
of the first plurality of holes. These two layers 36 and 37 are
preferably hot laminated in a preliminary step prior to the
insertion of discs 6B into apertures 4B.
[0036] It will be noted that, where cavities are provided in the
first plastic sheet, it is possible to provide discs with
dimensions such that the discs do not come into contact with the
lateral wall of the cavities, the connection between these discs
and the first sheet being achieved via the bottom of the cavities.
It is thus possible for a circular space (empty space) to remain
inside the cavities around the discs.
[0037] A fourth embodiment of a bimaterial plastic sheet 40
according to the invention is shown in FIG. 7. The fourth
embodiment differs in that the discs 6C inserted into apertures 4
of the first sheet 2 each have a profile in the general plane of
the first sheet which is different from the contour of the
corresponding aperture. In the fabrication method described above,
the initial profile of disc 6C is selected such that, during step
C) of the method, protruding portions of the disc come into contact
with the lateral wall 20 of the corresponding aperture 4, while
leaving empty areas 39 in the aperture. During the final pushing in
of discs 6C, the protruding portions are slightly deformed due to
the pressure exerted by lateral wall 20 on said protruding portions
which eventually adhere to the first material forming first sheet
2. In a variant, only a small amount of heat is provided to deform
the discs and ensure the connection thereof to the first sheet. It
will be noted that it is also possible to provide at least one
recess in the disc, particularly in the central area. Preferably,
this recess is made in accordance with the electronic unit or units
to be inserted into the corresponding aperture. For example, the
recess will be positioned in an area provided for the thickest
portion of the electronic unit or, in the case of several
electronic units inserted into the same aperture in first sheet 2;
the recess will be positioned in the area provided for the thickest
electronic unit. In a variant, it is the most fragile portion of an
electronic unit or the most fragile electronic unit of the
electronic units used which is positioned in the area of the
recess.
[0038] FIG. 8 shows a schematic view of one use of a plastic sheet
22A according to the invention in a first smart card fabrication
method. The plastic sheet 22A is placed on a support 12A. The
plastic sheet is similar to the plastic sheet 22 described above,
with the addition of an electrical circuit arranged on top face 8.
At the periphery of each area 5 defined by a disc 6 of low
hardness, this electrical circuit includes contact pads 44 for
electrical connection to an electronic unit 46. Electronic unit 46
and conductive segments 48 are moved above plastic sheet 22A using
a gripping tool 50 so that the electronic unit is located above a
disc 6. Next, the gripping tool lowers the assembly formed of the
electronic unit and conductive segments towards disc 6 and inserts
electronic unit 46 into the relatively soft material forming the
disc. Thus, the electronic unit easily penetrates the plastic sheet
according to the invention. In a variant, the material forming disc
6 is compressible. The intermediate product 52 shown in
cross-section in FIG. 9 is then obtained. The material of disc 6 is
either compressed or in a compressed state. In another variant,
notably with an integrated circuit of small dimensions, the
material forming disc 6 comes out of aperture 4 slightly when the
electronic unit penetrates the aperture. This may permit the top
surface of the integrated circuit to be partially covered and
prevent any subsequent electrical problems between the integrated
circuit and the conductive segments 48 which must only have
electrical contact with one determined pad of the integrated
circuit. In a variant implementation, disc 6 has a lower Vicat
softening temperature and the penetration of electronic unit 46
into the disc is achieved by applying heat to soften the disc
quickly without deforming first sheet 2 and without any risk of
damaging the electronic unit.
[0039] FIG. 10 is a schematic view of one use of a plastic sheet 56
according to the invention in a second smart card fabrication
method. Plastic sheet 56 is formed by a plastic sheet 32 described
above and a continuous plastic film 58 closing apertures 4B on the
rear face side of plastic sheet 32. It is noted that apertures 4B
define a plurality of cavities in plastic sheet 56. A printed
circuit 54 with electronic units 46A arranged on the top surface
thereof is placed on a support 12. Plastic sheet 56 is placed
opposite printed circuit 58 and deposited on the printed circuit so
that the electronic units are located facing discs 6B. Next, using
a press, the electronic units are inserted into cavities 4B
penetrating the material forming discs 6B. During this penetration,
discs 6B are deformed and at least substantially fill the annular
areas 35 by displacing the material of the discs so as to
substantially reduce the spaces initially remaining in cavities 4B.
A smart card 60 shown in cross-section in FIG. 11 is thus
obtained.
* * * * *