DE4337920A1 - Method and arrangement for producing a permanent electrical pressure contact - Google Patents

Abstract

The invention is based on the object of specifying a method and an arrangement, by means of which method the contact pairs of two conductor foils (which are fitted onto plastic parts) can be produced permanently and reliably without any high temperature stress and without any additional adjustment cost. The method and the arrangement are also intended to be suitable for the productive manufacture of smart cards without any contacts and having a laminated layered construction. The object is achieved according to the invention by a method and an arrangement, in the case of which method the contact surfaces of the conductor track carriers are placed one on top of the other, and the conductor track carriers which surround the contact surfaces and are located one on top of the other are subsequently welded under pressure and at a temperature of more than 140 DEG C. The invention relates to a method and an arrangement for producing a permanent electrical pressure contact on two conductor track carriers made of plastic and having metallic contact surfaces or having contact surfaces made of conductive polymers which are provided with carbon or metal additives, preferably for contacts in laminated smart cards. <IMAGE>

Description

The invention relates to a method and an arrangement to generate a permanent electri pressure contact on two interconnect carriers Plastic with metallic contact surfaces or with Contact surfaces made of conductive polymers, which are provided with carbon or metal additives, preferably for contacts in laminated chipkar ten.

It is not known in the prior art detachable electrical connections between the con tact areas of two flat flexible conductor tracks Carrier made of plastic by adhesive, clamp or To make soldered connections. Such trace Carriers are, for example, flexible printed circuit boards or flexible conductor foils.

The disadvantage of solder connections is that relative high temperatures must be applied and that the heat input to the between the conductor tracks happy contact surfaces over the plastic must be done or that the plastic also on Soldering temperature is heated. Plastics with tempe Resistance to temperatures below 200 ° C can therefore  not be used for this type of contact. The sole one is also unfavorable in the operating case Power transmission between the conductor carriers over the contact areas connected by soldering couples. The resulting mechanical loading loads can destroy the solder joint or to tear off the contact area from the conductor track lead carrier.

When gluing contact surfaces using elec The eventu. is also a tric conductive adhesive necessary power transmission between the lei web carriers via the electrical contacts accomplished. It is also technically incorrect always expensive and expensive to dose the conductive adhesive and position the adhesive partners together the to adjust and as long as in adjusted and ar to hold each other until the Adhesive connection is hardened.

There is still an arrangement in the prior art known in the by electrically insulating Kle Via the conductor track carrier outside the contact area pairings are glued together. Because of who the high bond strengths of the two Lei Trerbahnträger achieved among themselves, is disadvantageous however, that glue between the conductor carriers must be introduced and the required pre precise adherence to adhesive parameters, adhesive thickness and Thickness of the contact areas.

The use of anisotropic is also known Adhesive films, their partial electrical  Conductivity only in zones of increased pressure, so generally in the area of the respective intended contact pairing due to the thickness the contact area. But is a further one processing of the printed circuit boards by lamination provided in thicker composites, the adhesive film with its mechanical and thermal properties ten are taken into account, which becomes a complicated plastic card structure.

It is also known in the prior art to use the lei terfolien together by elastic clamping pieces press. However, this type of contact is with the disadvantage of the high space requirement due to the Clamping pieces and the penetration of moisture into the Area of the contact pairing connected.

The invention has for its object a Ver drive and specify an arrangement with which the Contact pairs of two on plastic parts brought conductive foils permanently and reliably without high temperature stress and without additional Adjustment effort can be made. The Ver drive and the arrangement should also for the pro ductive production of contactless chip cards with la mined layer structure.

According to the invention, the task is accomplished by a method ren solved, in which the contact surfaces of the conductors stacked the web carrier and then the the contact areas surrounding one another  Conductor track under pressure and at a tempera more than 140 ° C are welded.

A particular advantage of the Ver driving is that no additional materials such as solder, glue, adhesive film, clamping pieces etc. are needed and that the connection me is very firm and relatively dense.

It is also possible that the leads with egg coated with an adhesive material that is coated with the Plastic under the same pressure and tempera is weldable under which the Track carriers are welded.

The arrangement according to the invention results from that the conductor track carrier made of weldable art material, which up to temperatures of 120 ° C is elastic and no significant pla Sticity and the contact surfaces and the Leads in welded, surrounding, conductor tracks lying one on top of the other.

The contact areas must be dimensioned sufficiently wide sion, so that when laminating the weldable ren plastic flow of plastic Plastic no contact uncertainties due to con clock withdrawals.

Are the superimposed interconnect carriers made of non-weldable flexible and electrically insulating materials, so it is partial if this conductor carrier at least  three to four times the width of the contact areas have and the pressed conductor track backing of weldable plastic on all sides ben are.

Further advantageous refinements of the inventions arrangement according to the invention are in claims 4 to 9 described.

Due to the mechanically non-releasable welding the conductor track carrier and by the pressure at Ver welding and as a result of the cooling of the ver welded conductor carrier after welding stronger than the contact metals together pulling the plastic creates a mechanical Pressure of the metallic contact surfaces against each other the one that is characterized by the elastic properties of the Plastic is maintained.

As a material for the conductor track carrier are before preferably polyester or polycarbonate. It however, other plastics can also be used that have a greater thermal expansion coefficient in the temperature range less than 120 ° C own than the traces and the contact surfaces.

To improve contact, the waiters surfaces of the metallic contacts with precious metal be coated.

It is also advantageous to use at least the upper area of contact with areas of greater roughness to provide depth. Press the roughness tips  with very high pressure on the surface of the con cycle partners and generate via micro welds safe electrical connections.

It is also advantageous if at least one Edge of a contact surface on the other contact area of the contact partner. Along the can ten result in increased pressures, which lead to a Improve contact.

To have a good electrical connection and a high one to achieve mechanical strength The area of the contact surface pair structured in this way be that the ratio of area of contact surface pair plus supply line to the welding surface of the adjacent or enclosed welding areas is minimal.

Further advantageous effects can be achieved, if the contact surface pairs and their leads from a completely closed welding area are surrounded and / or if the supply lines with egg coated with an adhesive substance, the deal with the plastic under the same pressure and the same temperature under which the conductor track supports are welded.

The invention is based on an off management example explained in more detail. In the associated show the drawing:  

Fig. 1 is a perspective view of two conductors to be connected path carriers,

Fig. 2 shows a section through the erfindungsge Permitted arrangement,

Fig. 3 shows two possible designs of the contact surfaces and

Fig. 4, the coverage of two contact surfaces with offset.

In the embodiment shown in FIG. 1, the upper conductor carrier 1 and the lower conductor carrier 2 made of polycarbonate plastic each have two feed lines 3 which end in contact surfaces 4 . The contact surfaces 4 are coated with the noble metal gold with a layer thickness of, for example, 0.1 μm. The thickness of the feed lines 3 and the contact surfaces 4 is 20 μm in the example. The contact area size is assumed to be 0.5 mm². The conductor carrier 1 and 2 are positio nated and placed one above the other and their thickness so selected that the contact surfaces 4 lie one above the other. The future welding areas 5 are hatched.

Fig. 2 shows in a section through the arrangement according to the dung OF INVENTION welding plane 5 after the welding of the upper conductor track carrier 1 with the lower conductor support 2. The plastic of the interconnect carriers 1 and 2 is intimately connected in the welding plane 5 , the contact surfaces 4 of the two interconnect carriers 1 and 2 press against each other with a slight offset and form two pairs of contact surfaces, which are separated from one another by the welded interconnect carrier material made of electrically insulating plastic are separated.

In Fig. 3 two examples to simplify the positioning of the contact surfaces 4 are shown to each other and to increase the mechanical strength of the weld. The contact surfaces 4 are star-shaped or ring-shaped. Since in the welding areas 5 the mechanical pressure caused by them on the contact surfaces pairs 4 is effective over the shortest distance. Since relatively small area sizes of the contact area pairs 4 of relatively large areas of the welding areas 5 are vice versa, even small incorrect positions of the contact areas to one another do not prevent the safe electrical connection. Good mechanical contact pressures result particularly from the star-shaped contact surface structure and the welding area enclosed in it.

Fig. 4 explains the effect of a slight incorrect positioning of the contact surfaces 4 of a pair of contact surfaces. In the area of overlap from contact edges 6 to contact surfaces 4 , there are mechanical pressure increases that have a contact-improving effect. These pressure increases are particularly effective with ring-shaped or star-shaped contact surface structures.

Reference list

1 upper conductor track carrier
2 lower conductor carriers
3 supply line
4 contact surface
5 welding area
6 contact edge

Claims (14)

1. Method for generating a permanent electrical pressure contact on two interconnect carriers made of plastic with contact surfaces characterized by the following process steps:

• - Stacking the contact surfaces ( 4 ) of the Lei terbahnträger ( 1 , 2 ) and
• - Connecting the superimposed interconnect carriers ( 1 , 2 ) surrounding the contact surfaces ( 4 ).

2. The method according to claim 1, characterized in that the connection of the contact surfaces ( 4 ) surrounding, superimposed interconnect carriers ( 1 , 2 ) is carried out by welding under pressure and at a temperature greater than 140 ° C. 3. The method according to claim 1, characterized in that the connection of the contact surfaces ( 4 ) surrounding, superimposed conductor track carrier ( 1 , 2 ) by pressing and laminating the conductor track carrier ( 1 , 2 ) in laminating layers he follows. 4. The method according to claim 2, characterized in that the feed lines ( 3 ) are coated with an adhesive insulating material ( 6 ) which can be welded to the plastic under the same pressure and temperature conditions under which the conductor track carrier ( 1 , 2nd ) are welded. 5. Arrangement for generating a permanent electrical pressure contact on two interconnect carriers with contact surfaces, characterized in that

• - The conductor carrier ( 1 , 2 ) consist of weldable plastic, which is elastic up to temperatures of 90 ° C and has no significant plasticity and
• - The contact surfaces ( 4 ) and the supply lines ( 3 ) are in welded surrounding, superimposed interconnect carriers ( 1 , 2 ).

6. Arrangement for generating a permanent electrical pressure contact on two interconnect carriers with contact surfaces, characterized in that

• - The conductor carrier ( 1 , 2 ) made of plastic hen and
• - The contact surfaces ( 4 ) and the feed lines ( 3 ) are in laminated welded printed conductor carriers.

7. Arrangement according to claim 5 or 6, characterized in that the thickness of the conductor track carrier ( 1 , 2 ) is greater than the thickness of the conductor tracks and their possible insulating layers or the thickness of the contact surfaces ( 4 ). 8. Arrangement according to one of claims 5 to 7, characterized in that the area portion of the contact surfaces ( 4 ) and their leads ( 3 ) or the lead insulation in the welding area ( 5 ) smaller than the area portion of the adjacent mutually welded conductor track pieces ( 1 , 2 ) is. 9. Arrangement according to one of claims 5 to 8, characterized in that the surfaces of the con tact surfaces ( 4 ) are coated with precious metal. 10. Arrangement according to one of claims 5 to 9, characterized in that the surface of at least one surface ( 4 ) of the contact surface pair has areas with a roughness depth greater than 2 microns. 11. An arrangement according to one of claims 5 to 10, characterized in that at least one edge (6) of a contact surface (4) on the other con tact surface (4) is of the contact area pair. 12. Arrangement according to one of claims 5 to 11, characterized in that the supply lines ( 3 ) are welded to the conductor track carriers ( 1 , 2 ). 13. Arrangement according to one of claims 6 to 12, characterized in that the superimposed are the non-weldable conductor carrier ( 1 , 2 ) are fixed by pressing and laminating in La minierschichten, the width of the conductor carrier ( 1 , 2 ) greater than twice is the contact area width. 14. Arrangement according to one of claims 5 to 12, characterized in that the contact surfaces ( 4 ) surrounding, superimposed interconnect carriers ( 1 , 2 ) are fixed by welding, the thickness of the welded composite including greater than four times an interconnect carrier Lich of its traces.