WO2005006499A1 - Improved method for crimping at least one connector contact on a flexible electronic circuit - Google Patents

Improved method for crimping at least one connector contact on a flexible electronic circuit Download PDF

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Publication number
WO2005006499A1
WO2005006499A1 PCT/FR2004/050303 FR2004050303W WO2005006499A1 WO 2005006499 A1 WO2005006499 A1 WO 2005006499A1 FR 2004050303 W FR2004050303 W FR 2004050303W WO 2005006499 A1 WO2005006499 A1 WO 2005006499A1
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WO
WIPO (PCT)
Prior art keywords
tooth
track
contact
flexible circuit
flexible
Prior art date
Application number
PCT/FR2004/050303
Other languages
French (fr)
Inventor
Yves Stricot
Frédéric Regnier
Flavio Fantini
Patrice Cappe
Liam Butterworth
Original Assignee
Fci
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fci filed Critical Fci
Priority to EP04767865A priority Critical patent/EP1656718A1/en
Publication of WO2005006499A1 publication Critical patent/WO2005006499A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R12/00—Structural associations of a plurality of mutually-insulated electrical connecting elements, specially adapted for printed circuits, e.g. printed circuit boards [PCB], flat or ribbon cables, or like generally planar structures, e.g. terminal strips, terminal blocks; Coupling devices specially adapted for printed circuits, flat or ribbon cables, or like generally planar structures; Terminals specially adapted for contact with, or insertion into, printed circuits, flat or ribbon cables, or like generally planar structures
    • H01R12/50—Fixed connections
    • H01R12/59—Fixed connections for flexible printed circuits, flat or ribbon cables or like structures
    • H01R12/65—Fixed connections for flexible printed circuits, flat or ribbon cables or like structures characterised by the terminal
    • H01R12/67—Fixed connections for flexible printed circuits, flat or ribbon cables or like structures characterised by the terminal insulation penetrating terminals
    • H01R12/68—Fixed connections for flexible printed circuits, flat or ribbon cables or like structures characterised by the terminal insulation penetrating terminals comprising deformable portions
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R43/00—Apparatus or processes specially adapted for manufacturing, assembling, maintaining, or repairing of line connectors or current collectors or for joining electric conductors
    • H01R43/02—Apparatus or processes specially adapted for manufacturing, assembling, maintaining, or repairing of line connectors or current collectors or for joining electric conductors for soldered or welded connections
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
    • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
    • H05K3/325—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by abutting or pinching, i.e. without alloying process; mechanical auxiliary parts therefor
    • H05K3/326—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by abutting or pinching, i.e. without alloying process; mechanical auxiliary parts therefor the printed circuit having integral resilient or deformable parts, e.g. tabs or parts of flexible circuits
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/03—Use of materials for the substrate
    • H05K1/0393—Flexible materials
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/11—Treatments characterised by their effect, e.g. heating, cooling, roughening
    • H05K2203/1189—Pressing leads, bumps or a die through an insulating layer
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/14—Related to the order of processing steps
    • H05K2203/1446—Treatment after insertion of lead into hole, e.g. bending, cutting, caulking or curing of adhesive but excluding soldering
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
    • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
    • H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
    • H05K3/341—Surface mounted components
    • H05K3/3421—Leaded components

Definitions

  • the invention relates to an improved method for crimping at least one connection contact on a flexible electronic circuit.
  • Flexible electronic circuits also called flexible circuits or "flex” are circuits generally consisting of a first sheet of flexible insulating material, on which are arranged electrically conductive tracks, for example copper. These conductive tracks are themselves covered, either by a second sheet of insulating material or by an insulating varnish.
  • Such flexible circuits are commonly used in the electrical industry and, in particular, in the electrical industry dedicated to the automobile.
  • connection techniques intended to connect these flexible circuits to electrical contacts or to electronic components. One of these techniques consists in using connection plates or connection contact.
  • connection plates are provided with piercing teeth forming one or more crown (s).
  • piercing teeth forming one or more crown (s).
  • the connection is made by means of clips piercing the flexible circuit. These clips are distributed on a connection plate above which the flexible circuit to be connected is placed.
  • Each of these staples has a ring of piercing teeth which pass through the flexible circuit and are then crimped onto the flexible circuit. The teeth are thus intended to pass through the flexible circuit from a lower face to an upper face and then be folded down by crimping against the upper face of the flexible circuit.
  • Such a flexible circuit pierced by such a connection plate has an acceptable electrical resistance to allow the passage of an amount of current conventionally used in the field of connectors through the conductive tracks.
  • the electrical resistance between a conductive track of the flexible circuit intended to be in contact with the tooth and the tooth is equal to 2 milliohms (m ⁇ ).
  • this electrical resistance is not low enough to allow the passage of a greater amount of current through the tracks of the flexible circuit.
  • the conductive tracks have a thickness of the order of 75 to 100 ⁇ m. To decrease the electrical resistance between the tooth and the track, one could increase a contact area between the tooth and the track in contact with the tooth. To increase the contact area of the tooth with the track, the thickness of such a conductive track could be increased.
  • the invention provides for solving this problem by increasing a contact surface between the tooth and the track at a location of the tooth intended to be in contact with the track. More particularly, the invention provides an improved method of crimping at least one connection contact on a flexible electronic circuit.
  • the tooth After piercing the flexible circuit, the tooth is heated in such a way that it is welded at a point on the track that it has already crossed. By welding to the track, the tooth fills the spaces between the tooth and the track at the location of the tooth crossing the track. By filling these spaces, the contact surface of the tooth with the track increases and then makes it possible to decrease the electrical resistance between the connection contact and the track.
  • This process involves the heating of the tooth using a heating bar which has the property of heating very quickly in a few seconds so as to immediately transfer the heat to the tooth without causing burning of the tooth and without burning of the tooth. flex while causing the tooth to weld with the track at the location of the tooth in contact with the track.
  • the bar is a tungsten bar capable of heat in 1 to 3 seconds.
  • This heating bar also has the property of welding the tooth without adding additional material.
  • the tooth is covered with a fusible conductive product such as for example a tin-lead mixture, a copper tin mixture, pure tin, a tin-silver-copper mixture, or nickel.
  • a fusible conductive product such as for example a tin-lead mixture, a copper tin mixture, pure tin, a tin-silver-copper mixture, or nickel.
  • connection contact relates to a method of crimping at least one connection contact on a flexible electronic circuit, the connection contact comprising at least one piercing tooth.
  • the flexible circuit comprising a flexible and thick strip delimiting a lower face and an upper face while being formed by a first sheet of insulating material, by at least one track electrically conductive, and by a second sheet of insulating material, characterized in that - the tooth is covered with a fusible conductive product, - the flexible circuit is pierced from the lower face to the upper face of the band through the piercing tooth, - one end of the tooth is folded against the upper face of the band, and - the tooth is heated is to carry out a welding of the tooth with the track at at least one place of the tooth intended to be in contact with the track.
  • FIG. 1 a schematic representation of an electronic circuit flexible provided with a connection contact, according to the invention
  • Figures 2a to 2b schematic representations of an embodiment of a ring of piercing teeth of a connection contact, according to the invention
  • - Figure 3 a three-dimensional schematic representation of a flexible electronic circuit provided with a connection contact, according to the invention
  • - Figures 4a to 4d schematic representations of the different stages of a crimping process of a connection contact on a flexible circuit, according to the invention.
  • FIG. 1 a schematic representation of an electronic circuit flexible provided with a connection contact, according to the invention
  • Figures 2a to 2b schematic representations of an embodiment of a ring of piercing teeth of a connection contact, according to the invention
  • - Figure 3 a three-dimensional schematic representation of a flexible electronic circuit provided with a connection contact, according to the invention
  • - Figures 4a to 4d schematic representations of the different stages of a crimping process of a connection contact on
  • the flexible circuit forms a flexible and thick strip delimiting a lower face 3 and an upper face 4.
  • This flexible strip is formed from the lower face 3 to the upper face 4 by a first sheet of flexible insulating material 5, by at least one electrically conductive track 6, and by a second sheet of insulating material 7.
  • These conductive tracks can be deposited on the first sheet 5 and covered by the second sheet 7.
  • These conductive tracks can form one or more circuit patterns printed.
  • These tracks can be formed following the printing of a layer of electrically conductive ink on the first sheet 5.
  • This layer of ink 6 can essentially consist of copper or nickel or another conductive product. electricity.
  • this layer of ink forms a thickness 20 of 75 to 100 micrometers ( ⁇ m) in thickness and the flexible circuit can form a thickness 18 of 300 ⁇ m.
  • laminated copper will preferably be used.
  • the thickness 18 is measured in a direction perpendicular to a plane formed by the flexible circuit from the lower face 3 to the upper face 4.
  • the connection contact 2 is formed of an electrically conductive metal plate. This connection contact 2 can be formed by a plate of copper or other conductive material. This connection contact 2 also has an upper face 8 and a lower face 9. In the preferred example in FIG. 1, the connection contact 2 is placed with its upper face 8 attached to the lower face 3 of the circuit. flexible 1.
  • the connection contact 2 also comprises at least one piercing tooth, such as 10a, 10b, 10c, 1 ⁇ d, FIGS. 1 and 2b.
  • This piercing tooth can be part of a crown of teeth 11 as shown in FIGS. 2a to 2b.
  • This crown of teeth 11 may include four teeth 10a, 10b, 10c and 10d.
  • This crown of teeth 11 is formed after cutting the material formed by contact 2 over a whole thickness 12 of this same contact 2. To make this crown of teeth 11, a cross-shaped cutting is carried out throughout the thickness 12 of the contact 2. The cutting across the entire thickness 12 of the connection contact 2 is shown in dotted lines in FIG. 2a. The delimitation of the resulting teeth is shown in Figure 2b.
  • teeth are intended to be oriented perpendicularly to the plane formed by the contact 2. Preferably, they are located on the same side of the plane formed by the contact 2 so as to strengthen the approach of the contact 2 to the flexible circuit 1.
  • some of the piercing teeth 10 could be inclined by a first side and others by a second side of the plane formed by the contact 2 (not shown). In this case, provision may be made for placing an additional flexible circuit (not shown) against this same connection contact 2 so that the lower face 3 of this connection contact 2 is attached to an upper face (not shown) of this additional flexible circuit.
  • the flexible circuit 1 according to the invention and the additional flexible circuit would then be in communication with each other via the connection contact 2.
  • All of these teeth 10a, 10b, 10c and 10d form the crown of teeth 11 and delimit a central hollow space 13.
  • Each of the teeth has an end 10e, 10f, 10g, and 10h respectively with a shape which can be advantageously pointed to facilitate the piercing of the contact 2 through the flexible circuit. Either of these ends may have a rounded shape or a flattened shape.
  • the crimping process of the connection contact 2 on the flexible circuit 1 can be carried out as follows, FIGS. 4a to 4d.
  • the teeth are first covered with a fusible electrically conductive product.
  • FIG. 4a represents a cross section of the flexible circuit 1 and of the connection contact 2 with the flexible circuit 1 detached from the connection contact 2.
  • the connection contact 2 is intended to come into contact with the flexible circuit 1 in such a way that the upper face 8 of this same contact 2 comes into contact with the lower face 3 of the circuit 1.
  • This approximation of the upper face 8 to the lower face 3 is represented by arrows F in FIG. 4a .
  • the teeth 10a, 10b, 10c, and 10d pass entirely through the flexible circuit 1 from the lower face 3 to the upper face 4, passing successively through the first insulating layer 5, through the conductive layer 6 and through the second insulating layer 7.
  • Each of the teeth 10a, 10b, 10c and 10d passes entirely through the circuit 1 with a position of each of the teeth relatively perpendicular to a plane formed by the contact 2.
  • the drilling of the teeth 10a, 10b , 10c and 10d through the flexible circuit 1 can be facilitated due to the pointed shape of the ends of the teeth.
  • Each of the teeth 10 is then in contact with the track along a first portion 15 of the tooth. The dimension of this first portion 15 depends on a thickness 20 of the track 6.
  • FIG. 3 illustrates a perspective representation of a flexible circuit 1 provided with the connection contact 2 according to the invention.
  • the term crimp each of the teeth 10a, 10b, 10c and 10d on the upper face 4 of the flexible circuit 1, the fact of folding against the upper face 4 of the flexible circuit each of these teeth 10 in the direction opposite to the central space 13
  • the teeth 10 are folded against the upper face 4 of the flexible circuit towards the outside of the crown of teeth 11. These teeth can be folded down by means of a punch.
  • Each of the teeth has a height 17 at least greater than the thickness 18 of the flexible circuit 1, FIG. 2b. This height 17 is measured in a direction perpendicular to the plane formed by the contact 2 between the upper face 8 of the contact 2 and the end of each of the teeth.
  • a flexible circuit 1 has a thickness of 300 ⁇ m and in this case the height 17 of each of the teeth must be at least greater than 300 ⁇ m to allow the tooth to fall back against the upper face 4.
  • at least one of the teeth such as 10a, 10b, 10c and 10d is heated so as to weld the tooth with the track at at least one location of the tooth in contact with the track.
  • the tooth is in contact with the track along a first portion 15 of the tooth.
  • the conductive product allows the tooth to come to be welded to the track by its first portion 15.
  • Each of the teeth can be heated by means of a heating bar 14.
  • the heating is represented by the wavy arrows F "on the Figure 4c.
  • the heating bar is intended to make a weld which is similar to a soldering of the tooth on the track. By soldering is meant the fact that there is a weld of the portion of the tooth with the portion of corresponding track without providing additional material but only a contribution of the fusible conductive product covering the tooth.
  • This heating bar also has the property of immediately heating the tooth in a few seconds while rising very high in temperature so as to transfer the heat to the tooth immediately without burning the tooth or flex. In one example, the bar heats up to 1000 ° C in 1 to 3 seconds. The heating on the tooth can be done in 1 to 3 seconds only.
  • This heating bar 14 can be a tungsten bar.
  • This brazing has the advantage of filling possible spaces 20 between the tooth and the track at a location of the tooth in contact with the track. These spaces 20 are likely to remain after the tooth has been pierced through the flexible circuit 1. These spaces are responsible for a reduction in the contact surface between the tooth and the track. These spaces 20 are filled following the welding of the tooth to the track at a location of the tooth in contact with the track.
  • the welding of the tooth with the track is carried out in such a way that spaces 20 present between the portion 15 of the tooth and the corresponding portion of track are filled.
  • the tooth is then in contact with the track over an entire surface delimited by the portion 15.
  • the electrical conductivity is increased and the electrical resistance decreased.
  • the electrical resistance of such a flexible circuit provided with this connection contact according to the invention is 0.2 m ⁇ .
  • at least one of the teeth can also be welded to a second location 16 of the tooth on the conductive track 6. This tooth is welded a second time so that the second sheet 7 is completely pierced once again from the upper face 4 of the flexible circuit and in the direction of the conductive track 6.
  • This second sheet 7 is completely pierced following local abrasion in a thickness 19 of the second insulating sheet 7. Localized abrasion is carried out following heating by the heating bar 14 on one end of the tooth.
  • the heating of the ends 10e and 10g of the teeth 10a and 10c respectively is represented by an arrow F ′ "in FIG. 4d.
  • This abrasion located through the second insulating layer 7 is produced so that the end of the tooth comes in contact with the conductive track 6, as shown in FIG. 4d.
  • This local abrasion of the second insulating sheet 7 is carried out while heating one end of each of the teeth so as to melt the conductive product covering the end of the tooth.
  • connection contact 2 is then in contact with the conductive track 6 according to a first contact zone 15 and according to a second contact zone 18, FIGS. 1 and 4d
  • the first contact zone 15 corresponds to a place in the tooth intended to be in contact with the track 6 s next to a first piercing of the tooth right through the flexible circuit 1.
  • the second contact zone 16 corresponds to a place in the tooth intended to be in contact with the track 6 following a second piercing of the tooth to through the second sheet 7.
  • the electrical resistance can be reduced by one g factor 10 or from 2 m ⁇ to 0.2 m ⁇ . This also results in an increase in electrical conductivity. This electrical conductivity is all the more important as the first contact zone 15 and the second contact zone 16 of the end of the tooth are extended.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Metallurgy (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Coupling Device And Connection With Printed Circuit (AREA)

Abstract

The invention relates to an improved method for crimping at least one connector contact on a flexible electronic circuit. According to the invention, an electrical resistance between the flexible circuit and the connector contact is reduced by increasing the surface area of said contact by connection to at least one electrical conducting track (6), contained within said flexible circuit. The above is achieved with a flexible circuit having a connector contact provide with at least one piercing tooth soldered to a track by heating the tooth after the tooth has crossed the flexible circuit.

Description

Procédé amélioré de sertissage d'au moins un contact de raccordement sur un circuit électronique souple Improved method of crimping at least one connection contact on a flexible electronic circuit
L'invention concerne un procédé amélioré de sertissage d'au moins un contact de raccordement sur un circuit électronique souple. L'invention trouve des applications dans le domaine de la connectique et en particulier, de la connectique automobile. Les circuits électroniques souples, appelés aussi circuits flexibles ou « flex » sont des circuits constitués généralement d'une première feuille d'un matériau isolant souple, sur laquelle sont disposées des pistes conductrices d'électricité, par exemple en cuivre. Ces pistes conductrices sont elles- mêmes recouvertes, soit par une seconde feuille de matériau isolant soit par un vernis isolant. De tels circuits souples sont couramment utilisés dans l'industrie électrique et, en particulier, dans l'industrie électrique dédiée à l'automobile. Il existe actuellement plusieurs techniques de connexions destinées à raccorder ces circuits souples à des contacts électriques ou à des composants électroniques. Une de ces techniques consiste à utiliser des plaquettes de connexion ou contact de raccordement. Ces plaquettes de connexion sont munies de dents de percement formant une ou plusieurs couronne(s). Une telle technique est décrite dans le document US-A-4 749 368. D'après ce document, la connexion se fait au moyen d'agrafes perçant le circuit souple. Ces agrafes sont réparties sur une plaquette de connexion au-dessus de laquelle est placé le circuit souple à connecter. Chacune des ces agrafes comporte une couronne de dent de percement qui traversent le circuit souple et sont ensuite serties sur le circuit souple. Les dents sont ainsi destinées à traverser le circuit souple depuis une face inférieure jusqu'à une face supérieure pour ensuite se rabattre par sertissage contre la face supérieure du circuit souple. Un tel circuit souple transpercé par une telle plaquette de connexion présente une résistance électrique acceptable pour permettre le passage d'une quantité de courant classiquement utilisée dans le domaine de la connectique à travers les pistes conductrices. Dans un exemple, la résistance électrique entre une piste conductrice du circuit souple destinée à être au contact de la dent et la dent est égale à 2 milliohms (mΩ). Cependant, cette résistance électrique n'est pas suffisamment faible pour permettre le passage d'une plus grande quantité de courant à travers les pistes du circuit souple. Habituellement, les pistes conductrices possèdent une épaisseur de l'ordre de 75 à 100 μm. Pour diminuer la résistance électrique entre la dent et la piste, on pourrait augmenter une zone de contact entre la dent et la piste au contact de la dent. Pour augmenter la zone de contact de la dent avec la piste, on pourrait augmenter l'épaisseur d'une telle piste conductrice. Or, augmenter l'épaisseur de la piste conductrice provoquerait un éventuel durcissement du circuit souple et rendrait le coût de fabrication d'un tel circuit souple élevé. On s'est rendu compte qu'après percement de la dent à travers le circuit souple, la dent n'était pas parfaitement au contact de la portion de piste qu'elle est censée traverser. Des espaces subsistent entre la dent et la piste à un endroit de la dent au contact avec la piste après l'avoir traversée. On s'est rendu compte que ces espaces sont à l'origine de la résistance électrique élevée d'un tel circuit souple muni du contact de raccordement. C'est pourquoi, l'invention prévoit de résoudre ce problème en augmentant une surface de contact entre la dent et la piste à un endroit de la dent destinée à être au contact de la piste. Plus particulièrement, l'invention prévoit un procédé amélioré de sertissage d'au moins un contact de raccordement sur un circuit électronique souple. Après avoir transpercé le circuit souple, la dent est chauffée de telle manière qu'elle se soude à un endroit de la piste qu'elle a déjà traversée. En se soudant à la piste, la dent comble les espaces existant entre la dent et la piste a l'endroit de la dent traversant la piste. En comblant ces espaces, la surface de contact de la dent avec la piste augmente et permet alors de diminuer la résistance électrique entre le contact de raccordement et la piste. Ce procédé fait intervenir le chauffage de la dent à l'aide d'une barre chauffante qui a la propriété de chauffer très rapidement en quelques secondes de manière à transférer immédiatement la chaleur à la dent sans entraîner de brûlure de la dent et sans brûlure du flex tout en provoquant une soudure de la dent avec la piste à l'endroit de la dent au contact avec la piste. Dans un exemple, la barre est une barre de tungstène susceptible de chauffer en 1 à 3 secondes. Cette barre chauffante a également la propriété de réaliser une soudure de la dent sans apport de matière supplémentaire. Pour ce faire, la dent est recouverte d'un produit conducteur fusible comme par exemple un mélange d'étain-plomb, un mélange d'étain cuivre, de l'étain pur, un mélange d'étain-argent-cuivre, ou du nickel. Dans une variante de l'invention, pour augmenter une zone de contact du contact de raccordement avec une piste du circuit souple, au moins une extrémité d'une dent est soudée sur la piste après s'être rabattue contre la face supérieure du circuit souple. L'extrémité de la dent est soudée sur la piste conductrice tout en transperçant à nouveau cette deuxième feuille isolante. La deuxième feuille est transpercée suite à une abrasion locale de cette même feuille par la barre chauffante et entraînée par le chauffage de l'extrémité de la dent. Pour réaliser un tel circuit électronique souple muni de ce contact de raccordement, l'invention a donc pour objet un procédé de sertissage d'au moins un contact de raccordement sur un circuit électronique souple, le contact de raccordement comportant au moins une dent de percement s'étendant perpendiculairement à un plan formé par le contact de raccordement, le circuit souple comportant une bande souple et épaisse délimitant une face inférieure et une face supérieure tout en étant formée par une première feuille d'un matériau isolant, par au moins une piste conductrice d'électricité, et par une deuxième feuille d'un matériau isolant, caractérisé en ce que - on recouvre la dent d'un produit conducteur fusible, - on transperce le circuit souple depuis la face inférieure jusqu'à la face supérieure de la bande par l'intermédiaire de la dent de percement, - on replie une extrémité de la dent contre la face supérieure de la bande, et - on chauffe la dent de manière à réaliser une soudure de la dent avec la piste à un au moins un endroit de la dent destiné à être au contact avec la piste. L'invention sera mieux comprise à la lecture de la description qui suit et à l'examen des figures qui l'accompagnent. Celles-ci ne sont présentées qu'à titre indicatif et nullement limitatif de l'invention. Les figures montrent : - Figure 1 : une représentation schématique d'un circuit électronique souple muni d'un contact de raccordement, selon l'invention ; - Figures 2a à 2b : des représentations schématiques d'une réalisation d'une couronne de dents de percement d'un contact de raccordement, selon l'invention ; - Figure 3 : une représentation schématique tridimensionnelle d'un circuit électronique souple muni d'un contact de raccordement, selon l'invention ; - Figures 4a à 4d : des représentations schématiques des différentes étapes d'un procédé de sertissage d'un contact de raccordement sur un circuit souple, selon l'invention. La figure 1 illustre un circuit électronique souple 1 muni d'un contact de raccordement 2, selon l'invention. Le circuit souple forme une bande souple et épaisse délimitant une face inférieure 3 et une face supérieure 4. Cette bande souple est formée depuis la face inférieure 3 jusqu'à la face supérieure 4 par une première feuille d'un matériau isolant souple 5, par au moins une piste conductrice d'électricité 6, et par une deuxième feuille de matériau isolant 7. Ces pistes conductrices peuvent être déposées sur la première feuille 5 et recouvertes par la deuxième feuille 7. Ces pistes conductrices peuvent former un ou plusieurs motifs de circuits imprimés. Ces pistes peuvent être formées suite à une impression d'une couche d'encre conductrice d'électricité sur la première feuille 5. Cette couche d'encre 6 peut être essentiellement constituée par du cuivre ou par du nickel ou un autre produit conducteur d'électricité. Dans un exemple, cette couche d'encre forme une épaisseur 20 de 75 à 100 micromètres (μm) d'épaisseur et le circuit souple peut former une épaisseur 18 de 300 μm. Dans le cas où la couche d'ancre atteint environ 100 μm d'épaisseur, on utilisera préférentiellement du cuivre laminé. L'épaisseur 18 est mesurée selon une direction perpendiculaire à un plan formé par le circuit souple depuis la face inférieure 3 jusqu'à la face supérieure 4. Le contact de raccordement 2 est formé d'une plaque métallique conductrice d'électricité. Ce contact de raccordement 2 peut être formé par une plaque en cuivre ou autre matériau conducteur. Ce contact de raccordement 2 comporte également une face supérieure 8 et une face inférieure 9. Dans l'exemple préféré figure 1 , le contact de raccordement 2 est placé avec sa face supérieure 8 accolée à la face inférieure 3 du circuit souple 1. Le contact de raccordement 2 comporte également au moins une dent de percement, telle que 10a, 10b, 10c, 1θd, figures 1 et 2b. Cette dent de percement peut faire partie d'une couronne de dents 11 telle que représentée figures 2a à 2b. Cette couronne de dents 11 peut comporter quatre dents 10a, 10b, 10c et 10d. Cette couronne de dents 11 est formée après découpage de la matière formée par le contact 2 dans toute une épaisseur 12 de ce même contact 2. Pour réaliser cette couronne de dents 11 , un découpage en forme de croix est réalisé dans toute l'épaisseur 12 du contact 2. Le découpage dans toute l'épaisseur 12 du contact de raccordement 2 est représenté en traits pointillés sur la figure 2a. La délimitation des dents en résultant est représentée sur la figure 2b. Ainsi après découpage dans toute l'épaisseur 12 du contact de raccordement 2, quatre triangles formant chacun une dent telles que 10a, 10b, 10c et 10d sont délimités. Les dents sont destinées à être orientées perpendiculairement par rapport au plan formé par le contact 2. De préférence, elles sont situées par un même côté du plan formé par le contact 2 de manière à renforcer le rapprochement du contact 2 au circuit souple 1. Dans une variante, certaines des dents de percement 10 pourraient être inclinées par un premier côté et d'autres par un deuxième côté du plan formé par le contact 2 (non représenté). Dans ce cas, il peut être prévu de disposer un circuit souple supplémentaire (non représenté) contre ce même contact de raccordement 2 de telle manière que la face inférieure 3 de ce contact de raccordement 2 soit accolée à une face supérieure (non représentée) de ce circuit souple supplémentaire. Le circuit souple 1 selon l'invention et le circuit souple supplémentaire seraient alors en communication l'un avec l'autre par l'intermédiaire du contact de raccordement 2. L'ensemble de ces dents 10a, 10b, 10c et 10d forme la couronne de dents 11 et délimitent un espace creux central 13. Chacune des dents comporte une extrémité 10e, 10f , 10g, et 10h respectivement avec une forme qui peut être avantageusement pointue pour faciliter le percement du contact 2 à travers le circuit souple. Ou bien chacune de ces extrémités peut comporter une forme arrondie ou bien une forme aplatie. Le procédé de sertissage du contact de raccordement 2 sur le circuit souple 1 peut être réalisé de la manière suivante, figures 4a à 4d. Les dents sont d'abord recouvertes d'un produit conducteur d'électricité fusible. Au moins une des dents peut être recouverte d'un produit conducteur fusible de 1 à 5 μm d'épaisseur. Ce produit conducteur d'électricité fusible peut être formé préférentiellement par un mélange d'étain plomb. Ce produit peut également être un mélange d'étain cuivre, ou bien un mélange d'étain-cuivre argent ou bien de l'étain pur. La figure 4a représente une coupe transversale du circuit souple 1 et du contact de raccordement 2 avec le circuit souple 1 détaché du contact de raccordement 2. Lors d'une première étape, le contact de raccordement 2 est destiné à venir au contact du circuit souple 1 de telle manière que la face supérieure 8 de ce même contact 2 vienne se placer au contact de la face inférieure 3 du circuit 1. Ce rapprochement de la face supérieure 8 à la face inférieure 3 est représenté par des flèches F sur la figure 4a. Il en résulte figure 4b que les dents 10a, 10b, 10c, et 10d traversent entièrement le circuit souple 1 depuis la face inférieure 3 jusqu'à la face supérieure 4 en passant successivement à travers la première couche isolante 5, à travers la couche conductrice 6 et à travers la deuxième couche isolante 7. Chacune des dents 10a, 10b, 10c et 10d traverse entièrement le circuit 1 avec une position de chacune des dents relativement perpendiculaire à un plan formé par le contact 2. Le percement des dents 10a, 10b, 10c et 10d à travers le circuit souple 1 peut être facilité du fait de la forme pointue des extrémités des dents. Chacune des dents 10 est alors au contact de la piste selon une première portion 15 de la dent. La dimension de cette première portion 15 dépend d'une épaisseur 20 de la piste 6. Puis, après avoir traversé de part en part le circuit souple 1 , chacune des dents 10a, 10b, 10c et 10d est sertie sur la face supérieure 4 de ce circuit souple 1 , figures 3 et 4c. Le sertissage des dents est représenté par des flèches F' sur la figure 4b. La figure 3 illustre une représentation en perspective d'un circuit souple 1 muni du contact de raccordement 2 selon l'invention. On entend par sertir chacune des dents 10a, 10b, 10c et 10d sur la face supérieure 4 du circuit souple 1 , le fait de rabattre contre la face supérieure 4 du circuit souple chacune de ces dents 10 en direction opposée à l'espace central 13. Les dents 10 sont rabattues contre la face supérieure 4 du circuit souple vers l'extérieur de la couronne de dents 11. Ces dents peuvent être rabattues au moyen d'un poinçon. Chacune des dents possède une hauteur 17 au moins supérieure à l'épaisseur 18 du circuit souple 1 , figure 2b. Cette hauteur 17 est mesurée selon une direction perpendiculaire au plan formé par le contact 2 entre la face supérieure 8 du contact 2 et l'extrémité de chacune des dents. Dans un exemple, un circuit souple 1 possède une épaisseur de 300 μm et dans ce cas la hauteur 17 de chacune des dents doit être au moins supérieure à 300 μm pour permettre à la dent de se rabattre contre la face supérieure 4. Selon un mode de réalisation préféré de l'invention, au moins une des dents telles que 10a, 10b, 10c et 10d est chauffée de manière à réaliser une soudure de la dent avec la piste à au moins un endroit de la dent au contact avec la piste. La dent est au contact de la piste selon une première portion 15 de la dent. Le produit conducteur permet à la dent de venir se souder à la piste par sa première portion 15. Chacune des dents peut subir un chauffage par l'intermédiaire d'une barre chauffante 14. Le chauffage est représenté par les flèches ondulées F" sur la figure 4c. La barre chauffante est destinée à réaliser une soudure qui s'apparente à une brasure de la dent sur la piste. On entend par brasure le fait qu'il se produit une soudure de la portion 15 de la dent avec la portion de piste correspondante sans apporter de matière supplémentaire mais uniquement un apport du produit conducteur fusible recouvrant la dent. Cette barre chauffante a également la propriété de réaliser un chauffage immédiat de la dent en quelques secondes tout en montant très haut en température de manière à transférer la chaleur à la dent immédiatement sans entraîner de brûlure de la dent ou du flex. Dans un exemple, la barre chauffe à 1000°C en 1 à 3 secondes. L'application d'une telle barre chauffante sur la dent peut s'effectuer en 1 a 3 secondes seulement. Cette barre chauffante 14 peut être une barre de tungstène. Cette brasure présente l'avantage de combler d'éventuels espaces 20 entre la dent et la piste à un endroit de la dent au contact de la piste. Ces espaces 20 sont susceptibles de subsister après le percement de la dent à travers le circuit souple 1. Ces espaces sont responsables d'une diminution de la surface de contact entre la dent et la piste. Ces espaces 20 sont comblés suite à la soudure de la dent à la piste à un endroit de la dent au contact de la piste. Plus précisément, la soudure de la dent avec la piste est réalisée de telle manière que des espaces 20 présents entre la portion 15 de la dent et la portion de piste correspondante sont comblés. La dent est alors au contact de la piste sur toute une surface délimitée par la portion 15. Ainsi, la conductivité électrique est augmentée et la résistance électrique diminuée. Dans un exemple, la résistance électrique d'un tel circuit souple muni de ce contact de raccordement selon l'invention est de 0,2 mΩ, Selon une variante de l'invention, au moins une des dents peut également être soudée à un deuxième endroit 16 de la dent sur la piste conductrice 6. Cette dent est soudée une deuxième fois de telle manière que la deuxième feuille 7 est entièrement transpercée une nouvelle fois depuis la face supérieure 4 du circuit souple et en direction de la piste conductrice 6. Cette deuxième feuille 7 est entièrement transpercée suite à une abrasion locale dans une épaisseur 19 de la deuxième feuille isolante 7. L'abrasion localisée est réalisée suite à un chauffage par la barre chauffante 14 sur une extrémité de la dent. Le chauffage des extrémités 10e et 10g des dents 10a et 10c respectivement est représenté par une flèche F'" sur la figure 4d. Cette abrasion localisée à travers la deuxième couche isolante 7 est réalisée de manière à ce que l'extrémité de la dent vienne au contact de la piste conductrice 6, comme représenté figure 4d. Cette abrasion locale de la deuxième feuille isolante 7 est réalisée tout en chauffant une extrémité de chacune des dents de manière à faire fondre le produit conducteur recouvrant l'extrémité de la dent. Le produit conducteur ainsi fondu crée une soudure d'au moins une des extrémités des dents sur la piste conductrice 6 à un deuxième endroit de la dent 16. Le contact de raccordement 2 est alors en contact avec la piste conductrice 6 selon une première zone de contact 15 et selon une deuxième zone de contact 18, figures 1 et 4d. La première zone de contact 15 correspond à un endroit de la dent destiné à être au contact de la piste 6 suite à un premier percement de la dent de part en part à travers le circuit souple 1. La deuxième zone de contact 16 correspond à un endroit de la dent destiné à être au contact de la piste 6 suite à un deuxième percement de la dent à travers la deuxième feuille 7. Il en résulte un circuit électronique souple présentant une résistance électrique sensiblement diminuée par rapport à un autre circuit souple muni d'un contact de raccordement habituellement rencontré dans l'état de la technique. Dans un exemple, la résistance électrique peut être diminuée d'un g facteur 10 ou de 2 mΩ à 0,2 mΩ. Il en résulte aussi une augmentation de la conductivité électrique. Cette conductivité électrique est d'autant plus importante que la première zone de contact 15 et la deuxième zone de contact 16 de l'extrémité de la dent sont étendues. The invention relates to an improved method for crimping at least one connection contact on a flexible electronic circuit. The invention finds applications in the field of connectors and in particular, automotive connectors. Flexible electronic circuits, also called flexible circuits or "flex" are circuits generally consisting of a first sheet of flexible insulating material, on which are arranged electrically conductive tracks, for example copper. These conductive tracks are themselves covered, either by a second sheet of insulating material or by an insulating varnish. Such flexible circuits are commonly used in the electrical industry and, in particular, in the electrical industry dedicated to the automobile. There are currently several connection techniques intended to connect these flexible circuits to electrical contacts or to electronic components. One of these techniques consists in using connection plates or connection contact. These connection plates are provided with piercing teeth forming one or more crown (s). Such a technique is described in document US-A-4,749,368. According to this document, the connection is made by means of clips piercing the flexible circuit. These clips are distributed on a connection plate above which the flexible circuit to be connected is placed. Each of these staples has a ring of piercing teeth which pass through the flexible circuit and are then crimped onto the flexible circuit. The teeth are thus intended to pass through the flexible circuit from a lower face to an upper face and then be folded down by crimping against the upper face of the flexible circuit. Such a flexible circuit pierced by such a connection plate has an acceptable electrical resistance to allow the passage of an amount of current conventionally used in the field of connectors through the conductive tracks. In one example, the electrical resistance between a conductive track of the flexible circuit intended to be in contact with the tooth and the tooth is equal to 2 milliohms (mΩ). However, this electrical resistance is not low enough to allow the passage of a greater amount of current through the tracks of the flexible circuit. Usually, the conductive tracks have a thickness of the order of 75 to 100 μm. To decrease the electrical resistance between the tooth and the track, one could increase a contact area between the tooth and the track in contact with the tooth. To increase the contact area of the tooth with the track, the thickness of such a conductive track could be increased. However, increasing the thickness of the conductive track would cause possible hardening of the flexible circuit and would make the cost of manufacturing such a flexible circuit high. We realized that after piercing the tooth through the flexible circuit, the tooth was not perfectly in contact with the portion of track it is supposed to cross. Spaces remain between the tooth and the track at a place of the tooth in contact with the track after having crossed it. It has been realized that these spaces are at the origin of the high electrical resistance of such a flexible circuit provided with the connection contact. This is why, the invention provides for solving this problem by increasing a contact surface between the tooth and the track at a location of the tooth intended to be in contact with the track. More particularly, the invention provides an improved method of crimping at least one connection contact on a flexible electronic circuit. After piercing the flexible circuit, the tooth is heated in such a way that it is welded at a point on the track that it has already crossed. By welding to the track, the tooth fills the spaces between the tooth and the track at the location of the tooth crossing the track. By filling these spaces, the contact surface of the tooth with the track increases and then makes it possible to decrease the electrical resistance between the connection contact and the track. This process involves the heating of the tooth using a heating bar which has the property of heating very quickly in a few seconds so as to immediately transfer the heat to the tooth without causing burning of the tooth and without burning of the tooth. flex while causing the tooth to weld with the track at the location of the tooth in contact with the track. In one example, the bar is a tungsten bar capable of heat in 1 to 3 seconds. This heating bar also has the property of welding the tooth without adding additional material. To do this, the tooth is covered with a fusible conductive product such as for example a tin-lead mixture, a copper tin mixture, pure tin, a tin-silver-copper mixture, or nickel. In a variant of the invention, to increase a contact zone of the connection contact with a track of the flexible circuit, at least one end of a tooth is welded to the track after being folded against the upper face of the flexible circuit . The end of the tooth is welded to the conductive track while again piercing this second insulating sheet. The second sheet is pierced following local abrasion of this same sheet by the heating bar and driven by the heating of the end of the tooth. To make such a flexible electronic circuit provided with this connection contact, the invention therefore relates to a method of crimping at least one connection contact on a flexible electronic circuit, the connection contact comprising at least one piercing tooth. extending perpendicular to a plane formed by the connection contact, the flexible circuit comprising a flexible and thick strip delimiting a lower face and an upper face while being formed by a first sheet of insulating material, by at least one track electrically conductive, and by a second sheet of insulating material, characterized in that - the tooth is covered with a fusible conductive product, - the flexible circuit is pierced from the lower face to the upper face of the band through the piercing tooth, - one end of the tooth is folded against the upper face of the band, and - the tooth is heated is to carry out a welding of the tooth with the track at at least one place of the tooth intended to be in contact with the track. The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These are presented for information only and in no way limit the invention. The figures show: - Figure 1: a schematic representation of an electronic circuit flexible provided with a connection contact, according to the invention; - Figures 2a to 2b: schematic representations of an embodiment of a ring of piercing teeth of a connection contact, according to the invention; - Figure 3: a three-dimensional schematic representation of a flexible electronic circuit provided with a connection contact, according to the invention; - Figures 4a to 4d: schematic representations of the different stages of a crimping process of a connection contact on a flexible circuit, according to the invention. FIG. 1 illustrates a flexible electronic circuit 1 provided with a connection contact 2, according to the invention. The flexible circuit forms a flexible and thick strip delimiting a lower face 3 and an upper face 4. This flexible strip is formed from the lower face 3 to the upper face 4 by a first sheet of flexible insulating material 5, by at least one electrically conductive track 6, and by a second sheet of insulating material 7. These conductive tracks can be deposited on the first sheet 5 and covered by the second sheet 7. These conductive tracks can form one or more circuit patterns printed. These tracks can be formed following the printing of a layer of electrically conductive ink on the first sheet 5. This layer of ink 6 can essentially consist of copper or nickel or another conductive product. electricity. In one example, this layer of ink forms a thickness 20 of 75 to 100 micrometers (μm) in thickness and the flexible circuit can form a thickness 18 of 300 μm. In the case where the anchor layer reaches approximately 100 μm in thickness, laminated copper will preferably be used. The thickness 18 is measured in a direction perpendicular to a plane formed by the flexible circuit from the lower face 3 to the upper face 4. The connection contact 2 is formed of an electrically conductive metal plate. This connection contact 2 can be formed by a plate of copper or other conductive material. This connection contact 2 also has an upper face 8 and a lower face 9. In the preferred example in FIG. 1, the connection contact 2 is placed with its upper face 8 attached to the lower face 3 of the circuit. flexible 1. The connection contact 2 also comprises at least one piercing tooth, such as 10a, 10b, 10c, 1θd, FIGS. 1 and 2b. This piercing tooth can be part of a crown of teeth 11 as shown in FIGS. 2a to 2b. This crown of teeth 11 may include four teeth 10a, 10b, 10c and 10d. This crown of teeth 11 is formed after cutting the material formed by contact 2 over a whole thickness 12 of this same contact 2. To make this crown of teeth 11, a cross-shaped cutting is carried out throughout the thickness 12 of the contact 2. The cutting across the entire thickness 12 of the connection contact 2 is shown in dotted lines in FIG. 2a. The delimitation of the resulting teeth is shown in Figure 2b. Thus after cutting through the entire thickness 12 of the connection contact 2, four triangles each forming a tooth such as 10a, 10b, 10c and 10d are delimited. The teeth are intended to be oriented perpendicularly to the plane formed by the contact 2. Preferably, they are located on the same side of the plane formed by the contact 2 so as to strengthen the approach of the contact 2 to the flexible circuit 1. In a variant, some of the piercing teeth 10 could be inclined by a first side and others by a second side of the plane formed by the contact 2 (not shown). In this case, provision may be made for placing an additional flexible circuit (not shown) against this same connection contact 2 so that the lower face 3 of this connection contact 2 is attached to an upper face (not shown) of this additional flexible circuit. The flexible circuit 1 according to the invention and the additional flexible circuit would then be in communication with each other via the connection contact 2. All of these teeth 10a, 10b, 10c and 10d form the crown of teeth 11 and delimit a central hollow space 13. Each of the teeth has an end 10e, 10f, 10g, and 10h respectively with a shape which can be advantageously pointed to facilitate the piercing of the contact 2 through the flexible circuit. Either of these ends may have a rounded shape or a flattened shape. The crimping process of the connection contact 2 on the flexible circuit 1 can be carried out as follows, FIGS. 4a to 4d. The teeth are first covered with a fusible electrically conductive product. At least one of the teeth can be covered with a fusible conductive product 1 to 5 μm thick. This fusible electrically conductive product can preferably be formed by a mixture of lead tin. This product can also be a mixture of copper tin, or a mixture of silver tin-copper or pure tin. FIG. 4a represents a cross section of the flexible circuit 1 and of the connection contact 2 with the flexible circuit 1 detached from the connection contact 2. During a first step, the connection contact 2 is intended to come into contact with the flexible circuit 1 in such a way that the upper face 8 of this same contact 2 comes into contact with the lower face 3 of the circuit 1. This approximation of the upper face 8 to the lower face 3 is represented by arrows F in FIG. 4a . It follows from FIG. 4b that the teeth 10a, 10b, 10c, and 10d pass entirely through the flexible circuit 1 from the lower face 3 to the upper face 4, passing successively through the first insulating layer 5, through the conductive layer 6 and through the second insulating layer 7. Each of the teeth 10a, 10b, 10c and 10d passes entirely through the circuit 1 with a position of each of the teeth relatively perpendicular to a plane formed by the contact 2. The drilling of the teeth 10a, 10b , 10c and 10d through the flexible circuit 1 can be facilitated due to the pointed shape of the ends of the teeth. Each of the teeth 10 is then in contact with the track along a first portion 15 of the tooth. The dimension of this first portion 15 depends on a thickness 20 of the track 6. Then, after passing right through the flexible circuit 1, each of the teeth 10a, 10b, 10c and 10d is crimped on the upper face 4 of this flexible circuit 1, Figures 3 and 4c. The crimping of the teeth is represented by arrows F ′ in FIG. 4b. FIG. 3 illustrates a perspective representation of a flexible circuit 1 provided with the connection contact 2 according to the invention. The term crimp each of the teeth 10a, 10b, 10c and 10d on the upper face 4 of the flexible circuit 1, the fact of folding against the upper face 4 of the flexible circuit each of these teeth 10 in the direction opposite to the central space 13 The teeth 10 are folded against the upper face 4 of the flexible circuit towards the outside of the crown of teeth 11. These teeth can be folded down by means of a punch. Each of the teeth has a height 17 at least greater than the thickness 18 of the flexible circuit 1, FIG. 2b. This height 17 is measured in a direction perpendicular to the plane formed by the contact 2 between the upper face 8 of the contact 2 and the end of each of the teeth. In one example, a flexible circuit 1 has a thickness of 300 μm and in this case the height 17 of each of the teeth must be at least greater than 300 μm to allow the tooth to fall back against the upper face 4. According to one mode In a preferred embodiment of the invention, at least one of the teeth such as 10a, 10b, 10c and 10d is heated so as to weld the tooth with the track at at least one location of the tooth in contact with the track. The tooth is in contact with the track along a first portion 15 of the tooth. The conductive product allows the tooth to come to be welded to the track by its first portion 15. Each of the teeth can be heated by means of a heating bar 14. The heating is represented by the wavy arrows F "on the Figure 4c. The heating bar is intended to make a weld which is similar to a soldering of the tooth on the track. By soldering is meant the fact that there is a weld of the portion of the tooth with the portion of corresponding track without providing additional material but only a contribution of the fusible conductive product covering the tooth. This heating bar also has the property of immediately heating the tooth in a few seconds while rising very high in temperature so as to transfer the heat to the tooth immediately without burning the tooth or flex. In one example, the bar heats up to 1000 ° C in 1 to 3 seconds. The heating on the tooth can be done in 1 to 3 seconds only. This heating bar 14 can be a tungsten bar. This brazing has the advantage of filling possible spaces 20 between the tooth and the track at a location of the tooth in contact with the track. These spaces 20 are likely to remain after the tooth has been pierced through the flexible circuit 1. These spaces are responsible for a reduction in the contact surface between the tooth and the track. These spaces 20 are filled following the welding of the tooth to the track at a location of the tooth in contact with the track. More specifically, the welding of the tooth with the track is carried out in such a way that spaces 20 present between the portion 15 of the tooth and the corresponding portion of track are filled. The tooth is then in contact with the track over an entire surface delimited by the portion 15. Thus, the electrical conductivity is increased and the electrical resistance decreased. In one example, the electrical resistance of such a flexible circuit provided with this connection contact according to the invention is 0.2 mΩ. According to a variant of the invention, at least one of the teeth can also be welded to a second location 16 of the tooth on the conductive track 6. This tooth is welded a second time so that the second sheet 7 is completely pierced once again from the upper face 4 of the flexible circuit and in the direction of the conductive track 6. This second sheet 7 is completely pierced following local abrasion in a thickness 19 of the second insulating sheet 7. Localized abrasion is carried out following heating by the heating bar 14 on one end of the tooth. The heating of the ends 10e and 10g of the teeth 10a and 10c respectively is represented by an arrow F ′ "in FIG. 4d. This abrasion located through the second insulating layer 7 is produced so that the end of the tooth comes in contact with the conductive track 6, as shown in FIG. 4d. This local abrasion of the second insulating sheet 7 is carried out while heating one end of each of the teeth so as to melt the conductive product covering the end of the tooth. conductive product thus melted creates a weld of at least one of the ends of the teeth on the conductive track 6 at a second location of the tooth 16. The connection contact 2 is then in contact with the conductive track 6 according to a first contact zone 15 and according to a second contact zone 18, FIGS. 1 and 4d The first contact zone 15 corresponds to a place in the tooth intended to be in contact with the track 6 s next to a first piercing of the tooth right through the flexible circuit 1. The second contact zone 16 corresponds to a place in the tooth intended to be in contact with the track 6 following a second piercing of the tooth to through the second sheet 7. This results in a flexible electronic circuit having a substantially reduced electrical resistance compared to another flexible circuit provided with a connection contact usually encountered in the prior art. In one example, the electrical resistance can be reduced by one g factor 10 or from 2 mΩ to 0.2 mΩ. This also results in an increase in electrical conductivity. This electrical conductivity is all the more important as the first contact zone 15 and the second contact zone 16 of the end of the tooth are extended.

Claims

REVENDICATIONS
1 - Procédé de sertissage d'au moins un contact de raccordement (2) sur un circuit électronique souple (1), le contact de raccordement comportant au moins une dent de percement (10a, 10b, 10c, 10d) s'étendant perpendiculairement à un plan formé par le contact de raccordement, le circuit souple comportant une bande (1 ) souple et épaisse délimitant une face inférieure (3) et une face supérieure (4) tout en étant formée par une première feuille (5) d'un matériau isolant, par au moins une piste conductrice d'électricité (6), et par une deuxième feuille (7) d'un matériau isolant, caractérisé en ce que - on recouvre la dent d'un produit conducteur fusible, - on transperce le circuit souple depuis la face inférieure jusqu'à la face supérieure de la bande par l'intermédiaire de la dent de percement, - on replie une extrémité de la dent contre la face supérieure de la bande, et - on chauffe la dent de manière à réaliser une soudure de la dent avec la piste à un au moins un endroit de la dent destiné à être au contact avec la piste. 2 - Procédé selon la revendication 1 , caractérisé en ce qu'on chauffe la dent pendant une durée de 1 à 3 secondes au moyen d'une barre chauffante. 3 - Procédé selon la revendication 2, caractérisé en ce qu'on utilise une barre chauffante de tungstène. 4 - Procédé selon l'une des revendications 1 à 3, caractérisé en ce qu'on recouvre la dent d'un produit conducteur fusible de 1 à 5 μm d'épaisseur. 5 - Procédé selon l'une des revendications 1 à 4, caractérisé en ce qu'on recouvre la dent d'un mélange d'étain-plomb, ou d'un mélange d'étain- cuivre, ou d'un mélange d'étain-cuivre-argent, ou d'étain pur. 6 - Procédé selon l'une des revendications 1 à 5, caractérisé en ce qu'on obtient une résistance électrique entre la dent et la piste à un endroit de la dent au contact avec la piste de 0,2 milliohms (mΩ). 7 - Procédé selon l'une des revendications 1 à 6, caractérisé en ce que - on chauffe une extrémité de la dent de telle manière que l'extrémité de la dent se soude à la piste conductrice d'électricité après avoir traversée une deuxième fois la deuxième feuille de matériau isolant. 1 - Method for crimping at least one connection contact (2) on a flexible electronic circuit (1), the connection contact comprising at least one piercing tooth (10a, 10b, 10c, 10d) extending perpendicularly to a plane formed by the connection contact, the flexible circuit comprising a flexible and thick strip (1) delimiting a lower face (3) and an upper face (4) while being formed by a first sheet (5) of a material insulating, by at least one electrically conductive track (6), and by a second sheet (7) of an insulating material, characterized in that - the tooth is covered with a fusible conductive product, - the circuit is pierced flexible from the lower face to the upper face of the strip via the piercing tooth, - one end of the tooth is folded against the upper face of the strip, and - the tooth is heated so as to produce a weld of the tooth with the track at a u at least one place on the tooth intended to be in contact with the track. 2 - Method according to claim 1, characterized in that the tooth is heated for a period of 1 to 3 seconds by means of a heating bar. 3 - Process according to claim 2, characterized in that a tungsten heating bar is used. 4 - Method according to one of claims 1 to 3, characterized in that the tooth is covered with a fusible conductive product of 1 to 5 microns thick. 5 - Method according to one of claims 1 to 4, characterized in that the tooth is covered with a tin-lead mixture, or a tin-copper mixture, or a mixture of tin-copper-silver, or pure tin. 6 - Method according to one of claims 1 to 5, characterized in that one obtains an electrical resistance between the tooth and the track at a location of the tooth in contact with the track of 0.2 milliohms (mΩ). 7 - Method according to one of claims 1 to 6, characterized in that - One end of the tooth is heated so that the end of the tooth is welded to the electrically conductive track after having crossed the second sheet of insulating material a second time.
PCT/FR2004/050303 2003-07-02 2004-07-01 Improved method for crimping at least one connector contact on a flexible electronic circuit WO2005006499A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP04767865A EP1656718A1 (en) 2003-07-02 2004-07-01 Improved method for crimping at least one connector contact on a flexible electronic circuit

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0350287A FR2857166A1 (en) 2003-07-02 2003-07-02 IMPROVED METHOD OF CRIMINATING AT LEAST ONE CONNECTING CONTACT ON A FLEXIBLE ELECTRONIC CIRCUIT
FR03/50287 2003-07-02

Publications (1)

Publication Number Publication Date
WO2005006499A1 true WO2005006499A1 (en) 2005-01-20

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EP (1) EP1656718A1 (en)
FR (1) FR2857166A1 (en)
WO (1) WO2005006499A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7410384B2 (en) 2006-05-16 2008-08-12 Fci Americas Technology, Inc. Electrical contact with stapled connection
DE102013206069B3 (en) * 2013-04-05 2014-05-22 Lear Corp. Method for manufacturing seat sensor arrangement in vehicle, involves placing connector and conductor tracks on conductors by insulation unit to electrically connect flat electrical cables and film contact sensor

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007068280A1 (en) * 2005-12-16 2007-06-21 Fci Crimping method and device manufactured thereby

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986006882A1 (en) * 1985-05-09 1986-11-20 Associated Enterprises, Inc. Method and mass termination connector with solder connections
US4749368A (en) * 1986-04-03 1988-06-07 E. I. Du Pont De Nemours And Company Contact strip terminal

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986006882A1 (en) * 1985-05-09 1986-11-20 Associated Enterprises, Inc. Method and mass termination connector with solder connections
US4749368A (en) * 1986-04-03 1988-06-07 E. I. Du Pont De Nemours And Company Contact strip terminal

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7410384B2 (en) 2006-05-16 2008-08-12 Fci Americas Technology, Inc. Electrical contact with stapled connection
US7422468B2 (en) 2006-05-16 2008-09-09 Fci Americas Technology, Inc. Electrical contact with stapled connection
DE102013206069B3 (en) * 2013-04-05 2014-05-22 Lear Corp. Method for manufacturing seat sensor arrangement in vehicle, involves placing connector and conductor tracks on conductors by insulation unit to electrically connect flat electrical cables and film contact sensor

Also Published As

Publication number Publication date
FR2857166A1 (en) 2005-01-07
EP1656718A1 (en) 2006-05-17

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