EP0964122B1 - Electronic device, especially electronic key - Google Patents

Abstract

The key uses an embedded structure with elastomer contacts. The electronic key comprises a body (C) provided with a blind hole (O) in which an insulating peg (D) is mounted. The peg contains an integrated circuit (IC) with two contact pads (8,9). These contact pads are connected to the periphery of the body by a block of elastomer material having unidirectional conductivity (B), and first and second contact elements (C1, C2). The block (B) lies between the contact pads and contact elements and is compressed between them in a direction which is transverse w.r.t. the axis of the blind hole (O). When the key is engaged in an appropriate electronic terminal, the integrated circuit is brought into contact with an electronic circuit contained within the terminal.

Description

The present invention relates to an electronic device comprising an integrated circuit intended to be connected to an external device such as an electronic terminal.

The present invention is particularly suitable for an electronic key that can be used, for example, to identify a wearer wishing to enter a zone with controlled access, or else to pay for a commodity supplied by an automatic distributor.

The operating principle of such a key is known per se: typically, it comprises an integrated circuit containing information in a living or read-only memory.

When the key is engaged in an appropriate electronic terminal, the integrated circuit is brought into electrical contact with an electronic circuit contained in the terminal.

The electronic circuit of the terminal can for example compare a code recorded in the memory of the integrated circuit with a reference code, or else activate a flow counter of units included in the memory of the integrated circuit. One such key is known from US-A-5,322,992.

Due to the fact that such a key must come into physical contact with an electronic terminal a large number of times, it is subjected to external aggressions, such as mechanical stresses, shocks, variations in temperature, humidity, which are detrimental to the durability of the integrated circuit or electrical connections.

For these reasons, it is important that the integrated circuit is particularly well protected against external aggressions.

In addition, it is essential that the electrical connections between the integrated circuit and the contact members external parts of the key can withstand such damage without damage.

In addition, it is essential to be able to mount the integrated circuit in the key without applying excessive force to it.

Finally, assembly must be able to be carried out with the minimum number of parts, assembled together as simply as possible, this both to increase the robustness of the assembly and to reduce manufacturing costs.

The present invention aims to provide an electronic key, and more generally an electronic device, satisfying the above-mentioned requirements.

This object of the invention is achieved, as well as others which will appear on reading what follows, with an electronic device, in particular an electronic key, intended to be connected to an external device such as an electronic terminal, remarkable in that it comprises a body provided with a hole defining a longitudinal direction corresponding to a direction of introduction into this hole, and an integrated circuit housed in this hole and comprising at least one contact pad, this contact pad being electrically connected to the periphery of said body by means comprising at least one compressible conductive member and at least one contact member serving to establish the electrical connection to said external device, said compressible conductive member being located between said contact pad and said contact member contact and being in a compressed state between said contact pad and said contact member in a direction substantially transverse to said longitudinal direction.

Thanks to these characteristics, the integrated circuit is protected and it is electrically connected to the periphery of the body of the device by robust means ensuring good electrical contact, and it is protected from the forces liable to be applied to these means.

According to other particular features of the invention: said hole is blind; said integrated circuit is provided with first and second contact pads extended substantially in the same plane; this circuit is located in a housing provided in an insulating sleeve mounted in said hole; and said compressible conductive member is a block of elastomeric material with unidirectional conduction which is in the compressed state respectively between said first and second contact pads and first and second contact members electrically insulated from each other, said first contact member extending inside said hole to the periphery of the body of said electronic device.

• la figure 1a est une vue en perspective schématique d'une clé électronique selon l'invention;
• la figure 1b est une vue en perspective éclatée et partielle d'un premier mode de réalisation d'une clé électronique selon l'invention;
• la figure 2 est une vue en coupe partielle de la clé assemblée de la figure 1b.
• la figure 3 est une vue en perspective éclatée et partielle d'un deuxième mode de réalisation d'une clé électronique selon l'invention;
• la figure 4 est une vue en coupe partielle de la clé assemblée de la figure 3, selon un plan de coupe défini par la ligne IV-IV de cette figure 3;
• la figure 5 est une vue en perspective éclatée et partielle d'un troisième mode de réalisation d'une clé électronique selon l'invention;
• la figure 6 est une vue en coupe partielle de la clé assemblée de la figure 5.

Other particular characteristics and advantages of the present invention will appear on reading the description which follows and on examining the appended drawings given solely by way of examples, and in which:

• Figure 1a is a schematic perspective view of an electronic key according to the invention;
• Figure 1b is an exploded and partial perspective view of a first embodiment of an electronic key according to the invention;
• Figure 2 is a partial sectional view of the assembled key of Figure 1b.
• Figure 3 is an exploded and partial perspective view of a second embodiment of an electronic key according to the invention;
• Figure 4 is a partial sectional view of the assembled key of Figure 3, along a section plane defined by line IV-IV of this Figure 3;
• Figure 5 is an exploded and partial perspective view of a third embodiment of an electronic key according to the invention;
• FIG. 6 is a partial sectional view of the assembled key of FIG. 5.

In these figures, identical reference numerals represent identical or similar members or elements.

It should be noted that in the description which follows the invention is intended to apply to an electronic key, an object which is particularly well suited for receiving it. However, it is understood that it can be incorporated into another electronic device comprising an integrated circuit intended to be connected to an external circuit. Such a support can be for example a smart card or any object that can be identified.

Referring now to Figure 1a which shows an overview of a key according to the invention.

As can be seen in this figure, the body Ca of this key is provided with a hole Oa, located for example at its periphery near its end and intended to contain an electronic unit.

The body Ca, intended to be engaged in an electronic terminal (not shown), can be manufactured in an electrically insulating material, such as plastic, or in an electrically conductive material, such as metal.

This body can also have a mechanical opening function of a lock, and for this purpose have suitable geometry.

Reference is now made to FIGS. 1b and 2, which show the various members of a first embodiment of an electronic device according to the invention, which in this case is an electronic key.

As can be seen in FIG. 1b, the electronic key comprises a body C, shown partially, provided with a blind hole O.

In what follows, the terms "longitudinal" and "longitudinally" will be used to denote a direction corresponding to a direction of introduction into the hole O, and the terms "transverse""and" transversely "will be used to denote a direction substantially perpendicular to this direction of introduction.

The hole O can be of any shape, and in particular of circular shape. It can be obtained during the molding of the body C or by machining this body.

An assembly comprising a first contact member C1, an insulating sleeve D, an integrated circuit IC, a block of elastomeric material with unidirectional conduction B and a second contact member C2, is intended to be mounted in the hole O.

The second contact member C2 comprises a cylindrical cup, the free end 1 of which defines an external contact surface and the bottom 2 of which has a cylindrical chamfered longitudinal extension 3, of axis coinciding with that of the cup.

The cylindrical bowl and the longitudinal extension 3 can be two pieces assembled or constitute a single piece.

The insulating sleeve D has the overall shape of a cylinder pierced axially by a cylindrical cavity 4. It further has, at its end 5 intended to come against the bottom 2 of the member C2, a parallelepipedal housing 6 communicating with the cavity 4 and opening onto the outside.

Finally, in its end opposite to the end 5, the sleeve D comprises a cylindrical recess 7 with an axis coincident with that of the cavity 4.

The socket D can be obtained by molding an electrically insulating material such as rubber.

The integrated circuit IC has a substantially parallelepiped shape corresponding to that of the housing 6, and it is provided with first 8 and second 9 contact pads extending parallel to each other over a length which may be that of the integrated circuit. The transverse median plane Π defines a plane of symmetry for the two ranges 8 and 9.

The block of unidirectional conduction elastomeric material B is conductive, when compressed, only in the direction of compression.

The first contact member C1 has substantially the shape of a rivet whose head 10 corresponds to the cylindrical recess 7, and whose rod 11 has a chamfered end and a diameter substantially equal to that of the cavity 4.

The length of the rod 11 is determined so that it does not cross the transverse median plane π. Similarly, the length of the cylinder 3 is chosen so that it does not cross this plane Π.

The first C1 and second C2 contact members can be obtained by machining or molding a rigid electrically conductive material, in particular metal.

The assembly of the key according to this first embodiment of the invention is carried out as described below.

The block of elastomeric material B is placed under the integrated circuit IC, that is to say against its first 8 and second 9 contact pads.

This assembly is introduced into the housing 6 of the insulating bushing D, so that the block B comes opposite the cavity 4, and that the contact pads of the integrated circuit extend transversely.

Advantageously, the face of the IC circuit intended to come against the bottom 2 of the second contact member C2 can be coated with a layer of insulating adhesive I, so as to protect the integrated circuit against parasitic currents.

The first contact member C1 is introduced into the cavity 4, and it is pushed in until its head 10 abuts against the bottom of the recess 7. In doing so, the chamfered end of the rod 11 of the the member C1 is placed under the block of elastomeric material B by compressing it transversely against the first contact pad 8 of the integrated circuit IC, which has the effect to establish a conductive path between this range and the member C1 and maintain the elements 8 and 9.

The insulating bushing thus equipped is then introduced into the second contact member C2, and it is pushed in until it comes to abut against the bottom 2. In doing so, the longitudinal extension 3 penetrates into the cavity 4 and its chamfered end is placed under the block of elastomeric material B by compressing it transversely against the second contact pad 9 of the integrated circuit IC, which has the effect of establishing a conductive path between this pad and the member C2.

According to a possible variant (not shown), an insulating sheet can be placed against the bottom 2, in order to protect the integrated circuit from any stray currents coming from the member C2.

The chamfers formed on the extension 3 and on the rod 11 make it possible to avoid shearing the block of elastomeric material B during assembly.

Given the conditions imposed on the respective length of the rod 11 and of the extension 3 (see above), there remains a space 12 between these two elements when they are in place in the cavity 4. This space 12 serves to electrically isolate the members C1 and C2 from each other. It is possible, as a variant, to place a block of insulating material in this space.

Finally, the assembly thus obtained is mounted in the hole O. It is advantageous to bear on the edges of the end 1 of the member C2 to carry out this operation, so as not to exert too great pressure on the insulating sleeve. D.

According to a preferred variant (not shown) when the body C is made of an electrically conductive material, the second contact member C2 can be reduced to the longitudinal extension 3 arranged at the bottom of the hole 0. In this case, the electrical continuity between the second contact pad 9 and the outside is provided by the body C. It is also possible to provide only a bottom 2 supporting the extension 3, this bottom being initially introduced into the hole 0.

Aside from the integrated circuit IC and the block of elastomeric material B which are placed without forcing in the housing 6 by means of appropriate clearances, the other assemblies are preferably carried out by tight adjustment.

By adjusting the parts one inside the other, the risk of moisture penetration is eliminated up to the integrated circuit.

We now understand that the electronic key according to the invention requires very few parts, that it is simple to assemble, and that it also makes it possible to minimize the forces exerted on the integrated circuit IC, both during its assembly and during its subsequent use.

The only significant forces which are exerted on the integrated circuit IC are the transverse compression forces exerted by the rod 11 and by the extension 3 on the block B. Advantageously, these forces are exerted in a transverse direction and they are largely absorbed by the block of elastomeric material B. A pressure exerted longitudinally on the member C1 hardly increases the mechanical stresses undergone by the integrated circuit according to an object of the invention.

Reference is now made to FIGS. 3 and 4, which show the various members of a second embodiment of an electronic key according to the invention.

The electronic key comprises a body C ', partially shown, provided with a blind hole O'. The body C 'is made of a conductive material.

The hole O ′ can be of any shape, and in particular of rectangular shape, as is shown diagrammatically in FIGS. 3 and 4.

On one of its side walls, the hole O 'has a parallelepiped conductive projection 13, integral with the body C'. The two free edges 14, 15 of this projection are chamfered.

The hole O 'and the projection 13 can be obtained by molding the body C' or by machining. The projection 13 may have come in one piece with the body C 'or be arranged in particular by probing after the formation of the hole O'.

The projection 13 constitutes a contact member C2 'similar to the contact member C2 described above.

An assembly comprising a contact member C1 ', an insulating socket D', an integrated circuit IC and a block of elastomeric material with unidirectional conduction B, is intended to be mounted in the hole O '.

The socket D 'has a lateral cavity 16 provided for the projection 13. It also has a L-shaped front cavity 17, formed in the center of its side 18 intended to be positioned outwards, and a rectangular housing 19 communicating with both with the lateral 16 and frontal 17 cavities.

The dimensions of this housing correspond to those of the volume defined by the stack of the integrated circuit IC on the block of uncompressed elastomer material B, except that the height H1 of this housing is slightly less than the height H2 of this stack.

Finally, the contact member C1 ′ has an L shape corresponding to that of the front cavity 17 and two chamfered edges 20, 21. This member C1 ′ can be obtained by machining or molding a rigid electrically conductive material such as metal.

The assembly of the key according to this second embodiment of the invention is carried out as follows (see Figure 4).

We start by placing the block of elastomeric material B under the integrated circuit IC, that is to say against its first 8 and second 9 contact pads. The face of the circuit IC intended to come against the wall of the hole O ′ can be coated with a layer of insulating adhesive I, so as to protect the integrated circuit.

This assembly is introduced laterally into the housing 19 of the insulating sleeve D ′, so that the block B faces the lateral cavities 16 and front 17 and that the contact pads of the integrated circuit extend longitudinally, and the contact member C1 'is introduced into the front cavity 17. In doing so, the chamfered part is placed under the block of elastomeric material B by compressing transversely against the first contact pad 8 of the integrated circuit IC, which has the effect of establishing a conductive path between this pad 8 and the member C1 '.

The insulating bushing thus equipped is then introduced into the hole O ', and it is pressed until it comes to abut against the bottom of this hole. In doing so, the projection 13 comes to fit into the lateral cavity 16, and the chamfered part of this projection comes to be placed under the block of elastomeric material B by compressing it transversely against the second contact pad 9 of the integrated circuit IC. A conductive path is thus established between this area 9 and the member C2 '.

The installation of the socket D 'in the hole O ' also has the effect of laterally blocking the integrated circuit IC and the block B.

Similarly to the preferred embodiment of the electronic key according to the invention, the various elements involved in the assembly are dimensioned so that there remains a space 12 'between the projection 13 and the member C1' once these elements are mounted.

According to a possible variant (not shown), the contact member C2 'can be formed by a conductive cup similar to that described above in the context of the first embodiment, this cup being pressed into the hole O' during assembly. This variant is useful when the body C ′ is not made of a conductive material.

Reference is now made to FIGS. 5 and 6 which show the various members of a third possible embodiment of an electronic key according to the invention.

The electronic key comprises a body C ", partially shown, provided with a blind hole O ''. The body C" is made of a conductive material.

An assembly comprising a first contact member C1 ", an insulating sleeve D '', an integrated circuit IC, a block of elastomeric material with unidirectional conduction B, an insulating block 23 and a second contact member C2", is intended to be mounted in hole O ".

The insulating sleeve D "has substantially the shape of a cylindrical bowl comprising a longitudinal cavity 24 one end of which is closed by a bottom 25, this bowl defining a volume corresponding substantially to that of the interior of the hole O".

A lateral cavity 26, of rectangular section for example, extends radially from the bottom of the front cavity 24 to the periphery of the member C2 ". The cavity 26 has one of its walls in the extension of the bottom 25.

The member C1 "comprises, under a part 27, intended to come against the bottom 25 of the insulating sleeve D", a parallelepiped housing 28 opening onto the outside and transversely passing through this member C1 ".

The height H3 of this housing is slightly less than the height H2 of the uncompressed stack of the IC, of the block B and of the longitudinal part of the insulating member 22.

The part 29 of the member C1 '' facing the end part 27 is shorter than the latter to form an extension of the lateral cavity 26.

The assembly of the key according to this third embodiment of the invention is carried out as follows.

The block of elastomeric material B is placed under the integrated circuit IC, that is to say against its first 8 and second 9 contact pads, and the insulating member 22 partially around this IC and of block B.

This assembly is introduced into the housing 28, slightly compressing the block B against the first track contact 8, so that the contact pads of the integrated circuit extend transversely.

The assembly thus obtained is introduced into the front cavity 24 of the insulating sleeve D ", and it is pushed in until the end 27 of the member C1" abuts against the bottom 25 of this cavity.

The insulating block 23 and the second contact member C2 "are then introduced into the lateral cavity 26 until they are in abutment against the block B.

The block 23 and the member C2 "are then lightly pressed against the block B, thus compressing this block against the second contact pad 9 of the integrated circuit.

By maintaining this compression, the insulating sleeve D '' is finally introduced into the hole O ", the member C2" then being in abutment against the side wall of the hole O ".

Of course, the invention is not limited to the embodiments described and shown which have been given only by way of example.

Thus, for example, the hole formed in the body of the key could be through and the 2 contact areas of the key located respectively at the two ends of this hole.

Finally, the side walls of the various hollow members described above may have projections and / or recesses used in particular for holding other members introduced at least partially inside these various hollow members.

Claims (12)

1. Electronic device, especially an electronic key, intended to be connected to an external device, such as an electronic terminal and including a body (C; C'; C") provided with a hole (O; O'; O") defining a longitudinal direction corresponding to a direction of insertion into said hole, and an integrated circuit (IC) housed in said hole and having at least a first contact pad (8; 9), characterised in that said first contact pad is electrically connected to the periphery of said body by means comprising at least one compressible conductive member (B) and at least a first contact member (C1; C1'; C1"; C2; C2'; C2") used to establish the electrical connection to said external device, said compressible conductive member being located between said first contact pad and said first contact member in a compressed state along a substantially transverse direction to said longitudinal direction, the perpendicular direction to said first contact pad being substantially parallel to said transverse direction.
2. Electronic device according to claim 1, characterised in that said integrated circuit (IC) is placed in a housing (6; 19; 28) resulting from the assembly of other elements (C1; C1'; C1"; D; D'; D") longitudinally engaged in said hole (O; O'; O").
3. Electronic device according to claim 2, characterised in that said integrated circuit (IC) is further provided with a second contact pad (9; 8) located in substantially the same general plane as said first contact pad and electrically connected to a second contact member (C2; C2'; C2"), and in that said compressible conductive member (B) is a block of elastomeric material with one-directional conductivity which is in the compressed state between said first and second contact pads and respectively said first and second contact members which are electrically isolated from each other.
4. Electronic device according to claim 3, characterised in that a cavity (4) passes through said sleeve (D) made of an insulating material, communicating with the housing (6) containing said integrated circuit (IC), in that said first and second contact pads (8, 9) of the circuit are arranged transversely in said housing, and in that said first contact member (C1) and at least part (3) of said second contact member (C2) are engaged facing each other in said cavity.
5. Electronic device according to claim 3, characterised in that said sleeve made of an insulating material (D'; D") has frontal (17; 24) and lateral (16; 26) cavities in which said first (C1'; C1") and second (C2'; C2") contact members are respectively engaged.
6. Electronic device according to claim 5, characterised in that said housing (19) containing said integrated circuit (IC) is formed in said sleeve made of an insulating material (C'), and in that it communicates with said frontal (16) and lateral (17) cavities, said first and second pads (8, 9) of said integrated circuit being arranged longitudinally in the housing.
7. Electronic device according to claim 5, characterised in that said housing (28) containing said integrated circuit (IC) is partially formed in said first contact member (C1"), said first and second pads (8, 9) of said integrated circuit being arranged transversely in the housing.
8. Electronic device according to any of claims 3 to 6, characterised in that said second contact member (C2) includes a conductive recess, extending to the periphery of the body of said electronic device and containing said sleeve made of an insulating material (D), said integrated circuit (IC), said block of elastomeric material with one-directional conductivity (B) and said first contact member (C1), and in that said second contact member includes a longitudinal extension (3; 13).
9. Electronic device according to claim 8, characterised in that said conductive recess and said longitudinal extension (3) are made in a single same piece.
10. Electronic device according to any of claims 3 to 7, characterised in that its body (C'; C") is formed of an electrically conductive material, and in that said second contact member (C2', C2") is electrically connected to the body inside said hole (O'; O").
11. Electronic device according to any of the preceding claims, characterised in that the various elements placed in said hole (O; O'; O") are kept secured to each other and in relation to the hole with a tight fit.
12. Electronic device according to any of the preceding claims, characterised in that said device is an electronic key, intended for example for identifying a carrier wishing to enter a zone with controlled access, or for paying for food provided by a dispensing machine.