Method for producing at least one electronic module on a metal retainer plate, including at least one electrical test

A method for producing, on a metal retainer plate, an electronic module undergoing an electrical test. Prior to a final overmolding that forms the exterior envelope of the electronic module, there is performed a limited initial overmolding of at least one electrical-connection zone, thus surrounding a free-end portion of a rough form of an insulating second securing bar, by establishing between these a non-conducting overmolded bridge, a first securing bar is cut off from a component or element in order to electrically isolate said at least one electrical-connection zone, and an electrical test is performed on the zone prior to the final overmolding of the exterior envelope, with the electronic component or element being secured to the insulating second securing bar and to the retainer plate by the overmolded bridge.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Phase Application of PCT International Application No. PCT/FR2017/052379, filed Sep. 7, 2017, which claims priority to French Patent Application No. 1658329, filed Sep. 8, 2016, the contents of such applications being incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to a method for producing at least one electronic module on a metal retainer plate, this method including at least one electrical test of said at least one electronic module. This production method is carried out on a metal retainer plate to which at least one electronic module is secured.

BACKGROUND OF THE INVENTION

An electronic module comprises at least one electronic component, of the microprocessor, integrated circuit, electromagnetic compatibility circuit, type, tracks and at least one electrical-connection element, of the electrical connecting element type, for example one or more connecting pins.

In the conventional way, the electronic component or components or the electrical-connection element or elements comprise at least one electrical-connection zone that is to be electrically tested. A number of electrical tests may thus be carried out on such an electrical module, preferably before final overmolding of the electronic module, so that faulty components or elements can, if necessary, be repaired or replaced.

According to the prior art, it is not possible to electrically test parts of an electronic module without this module being detached from the retainer plate. Because a retainer plate often supports several electronic modules, all of the modules have to be detached from the retainer plate and tested individually.

This is because the retainer plate is made of metal, as are the securing bars which are in direct electrical contact with an electronic component or an electrical-connection element. It is therefore not possible to isolate, on the electronic module, an electrical-connection zone that is to be tested. It is for this reason that the electronic module has to be detached from the retainer plate and tested individually.

This introduces a test-duration cost and also a handling cost.

Conducting an electrical test on an unfinished electronic module which therefore does not have the overmolded envelope of the electronic module encasing all the electronic components and electrical-connection elements of the electronic module is not possible given that, when the electronic module is detached from the retainer plate and from the securing bar or bars, there is no possible way of securing the components and elements to one another and that, when not detached from the retainer plate, the electrical-connection zones in the electronic module are not isolated, thereby rendering electronic testing impossible.

It is therefore commonplace not to test the electronic modules until they have been overmolded so that the electronic components and the electrical-connection elements are kept fixed relative to one another. In that case, when an electronic component or an electrical-connection element is defective, it is the entire electronic module that has to be rejected, thus increasing the rejection cost of an electronic module.

SUMMARY OF THE INVENTION

The problem that the present invention addresses is that of testing one or more electrical-connection zones of at least one electronic module secured to a metal retainer plate during the production thereof without the electronic module being detached from the retainer plate.

To this end, an aspect of the present invention relates to a method for producing, on a metal retainer plate, at least one electronic module comprising at least one electronic component or at least one electrical-connection element for connection to at least the component or the element undergoing at least one electrical test, the retainer plate comprising at least a first securing bar for securing said at least one component or element to the plate and at least one rough form of an insulating second securing bar having a free end pointing toward said at least one component or element, leaving a space between the end and the component or element, said at least one component or element comprising at least one electrical-connection zone that is to be electrically tested, notable in that:prior to a final overmolding that forms the exterior envelope of the electronic module, there is performed an initial overmolding limited to said at least one electrical-connection zone, thus surrounding a free-end portion of said at least one rough form of an insulating second securing bar, by establishing a non-electrically-conducting overmolded bridge in the space between the free-end portion and said at least one electrical-connection zone, the rough form and the associated overmolded bridge forming the insulating second securing bar,said at least one first securing bar is cut off from said at least one component or element in order to electrically isolate said at least one electrical-connection zone, andat least one electrical test is performed on said at least one electrical-connection zone, said at least one electronic component or connection element being secured to said at least one rough form of an insulating second securing bar and to the retainer plate by the overmolded bridge.

The designation “electronic component” covers any electronic component such as an integrated circuit, a capacitor, a resistor, an electromagnetic compatibility circuit, etc., but also covers any electrical interconnection between same, such as tracks.

The technical effect is that it allows at least one electrical test to be carried out on the or each electronic module supported by the metal retainer plate because of the presence of an electrically non-conducting overmolded bridge which therefore insulates one or more zones that are to be electrically tested from the retainer plate while at the same time securing a or each module to the retainer plate once the first metal securing bar or bars have been cut off from the or each module. It then follows that the or each module can be tested during the stages of its production, this being either before or after its final overmolding that forms a casing delimiting the electronic module. An electrical test can thus be performed with the electronic module still secured to the retainer plate.

The rough form or rough forms of the insulating second securing bars, which are made of metal like the first securing bar or bars, are not in direct contact with an electronic component or with an electrical connection element of the electronic module. It is the overmolded bridge that mechanically secures a rough form of an insulating second securing bar to the component or the element of the electronic module while at the same time electrically isolating the component or the element. It then follows that an aspect of the present invention confers upon an insulating second securing bar or bars a function of securing to the component or the element of the electronic module while at the same time maintaining the electrical isolation thereof, which is a function it or they did not have in the prior art. This is possible once the non-insulating first securing bar or bars have then been cut off.

The electrical test can be carried out either before overmolding of the external envelope or afterward, the electronic module still being secured to the retainer plate at least by the insulating second securing bar comprising a rough form and an overmolded bridge.

Advantageously, said at least one electrical test is carried out on said at least one electronic module still secured to the metal retainer plate, said at least one insulating second bar then being cut off at the overmolded bridge.

Prior to that, it is possible to have retained, without cutting them off, another or certain other first securing bars that have no influence on the isolation of one or more electrical-connection zones that are to be tested, these first securing bars therefore not disrupting the conducting of one or more electrical tests. In that case, such first securing bars can be cut off after final overmolding. Conversely, it is possible to have cut off all the first securing bars, the insulating second securing bar or bars alone then securing to the retainer plate the electronic module that is in the process of being produced.

Advantageously, the retainer plate comprises a frame secured to a respective end of said at least one first securing bar and of said at least one rough form of an insulating second securing bar, said at least one bar or rough form respectively having a free end at the opposite end to the end that is secured to the frame, said at least one component or element being secured to the free end of said at least one first securing bar.

One form of frame makes it possible, if need be, to house the most possible electronic modules within it and enables material savings on the retainer plate while at the same time providing effective securing to the electronic module or modules placed inside the frame. It is possible to mark on a corner of the frame information relating to the electronic module(s).

Advantageously, the retainer plate and said at least one first and second securing bar are produced as a single piece by creating a metal component by cutting, stamping or 3-D printing. The retainer plate is thus economical to produce while at the same time being mechanically strong.

Advantageously, the retainer plate is intended to support at least two electronic modules, said respective at least one electronic component and electrical-connection element of said at least two electronic modules being tested while secured to the retainer plate. This makes it possible to produce several electronic modules on the one same retainer plate while electrically testing them without detaching them from the retainer plate. It then follows that the electrical test or tests are conducted more easily than on electronic modules considered separately from one another.

Advantageously, said at least one electronic module comprises at least two zones that are to be electrically tested, the two zones being initially and partially overmolded, and being so independently of one another. The initial and partial overmolding therefore relates only to restricted zones that are to be electrically tested.

Advantageously, when said at least one electronic module that is to be produced has at least one connecting pin by way of an electrical-connection element having a zone that is to be electrically tested, said at least one connecting pin being connected to said at least one electronic component by one end, the rest of the connecting pin projecting from the envelope of the electronic module, the limited initial overmolding is also performed on an end portion of the connecting pin connected to said at least one electronic component.

The connecting pin or pins, part of which projects from the envelope of the electronic module, are thus held in place by a limited initial overmolding with respect to the electronic module that precedes the final overmolding of the envelope of the electronic module. That allows the connecting pin or pins to be held more effectively in addition to electrically isolating the connecting pin or pins. This initial overmolding can in part project from the exterior envelope that a casing of the electronic module will form, the casing being obtained by the final overmolding. The initial overmolding is not restricted to said at least one connecting pin and may cover other components of the electronic module.

Advantageously, the final overmolding and the limited initial overmolding are performed in an electrically insulating resin. For example, epoxy resin is a material often used for an overmolding that falls within the specific context of an aspect of the invention, as it is also a material that is electrically insulating.

An aspect of the invention also relates to an electronic module comprising at least one electronic component and at least one connecting pin extending in part outside a casing forming an envelope of the electronic module with an end portion connected to said at least one electronic component, notable in that the electronic module is produced in accordance with such a method, the electronic component and the end portion of said at least one connecting pin connected to said at least one electronic component bearing a limited initial overmolding which, in the case of the electronic component, ends at least flush with the exterior envelope that forms the casing of the electronic module.

“At least flush with” means that the end portion of the limited initial overmolding is at least at the same level as the exterior envelope or extends beyond the exterior envelope: it is therefore visible from the exterior envelope without projecting from this exterior envelope or projects by a limited amount with respect to this exterior envelope. “Flush with” means that the overmolded bridge has been cut off level with the casing but this cutting-off can also be done some distance from the casing while being at least flush.

It then follows that an electronic module produced according to a method according to an aspect of the invention is recognizable from an electronic module produced according to a method according to the prior art. The final overmolding and the limited initial overmolding are recognizable and the or each cut overmolded bridge. The same may also be true of a connecting pin having an initial overmolding portion that projects from the exterior envelope of the electronic module.

Specifically, another part of the limited initial overmolding, which is preferably not an overmolded bridge, may project from the casing of the electronic module. This is the case with a limited initial overmolding portion which surrounds the portion closest to the casing of one or more electrical-connection pins projecting from the casing. This overmolding portion may therefore be intercalated between the final overmolding and the connecting pins to supplement the final overmolding on the pin portions projecting from the casing. Initial overmolding portions projecting from the casing of the electronic module thus make it possible to differentiate an electronic module according to an aspect of the invention from a module according to the prior art.

According to an aspect of the present invention, the first securing bar or bars are cut off prior to final overmolding. There are therefore no portions of first securing bars definitively remaining in the electronic module and passing through the final overmolding as they do the prior art. This latter had the disadvantage of making it easier for corrosion to get in, given the presence of two different materials namely the metal and the electrically insulating resin, and given the possibility for oxidation of the portions of the first bars definitively remaining in the electronic module.

All this is of particular relevance when the electronic module forms part of a sensor working under high-temperature and harsh environmental conditions, such as in the case of a measurement sensor in a motor vehicle comprising such an electronic module. The ingress of and formation of a flow circuit for a liquid substance contained in the environment surrounding the electronic module could arise out of such a metal/electrically insulating resin interface.

In addition, the cutting-off of the first securing bar or bars at the level of the final overmolding would lead to cutting difficulties with the potential to damage the envelope of the electronic module. All of these disadvantages are avoided according to an aspect of the present invention.

An aspect of the invention also relates to a measurement sensor present in a motor vehicle, characterized in that it comprises such an electronic module.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In what follows, in the specific case of the embodiment of the electronic module according to an aspect of the present invention that is shown in the figures, the front of the electronic module is defined by its face adjacent to the integrated circuit and the rear of the electronic module is defined by its face via which the connecting pins protrude. What is meant by a “rough form of an insulating second securing bar” is an incomplete second-bar portion that will be combined with an overmolded bridge to form the insulating second securing bar proper.

The electronic module is shown inFIG. 7as an enlargement by comparison with the module ofFIGS. 1 to 6which is in the process of being produced. When reference is made to one or more specific figures, these figures are to be considered in combination with the other figures in order to ascertain the designated numerical references that are missing from this or these specific figure(s). For example, the reference20for an electronic module or the reference22for a casing is visible only inFIGS. 6 to 8, the electronic module being incomplete in the other figures, but these references will be used to denote the electronic module or the casing in general for all the figures. In the figures, a single one of the three tracks is reference11and a single one of the three pins by way of electrical-connection element is referenced4, but everything stated in respect of this referenced track or pin is valid for all the tracks or pins.

With reference to all the figures and notably toFIGS. 1 to 7, an electronic module being referenced20only inFIG. 7, an aspect of the present invention relates to a method for producing, on a metal retainer plate2, at least one electronic module20comprising at least one electronic component11,15and at least one electrical-connection element4, for example at least one pin4pointing toward the outside of an envelope of the electronic module20incorporating the majority of the electronic module20thereby forming a casing22, referenced inFIGS. 6 and 7.

InFIGS. 1 to 6, the electronic module20is shown with several electronic components, but this type of electronic module20with such components is nonlimiting to the scope of an aspect of the invention and merely illustrative of one electronic module20among so many others for which a production method according to an aspect of the present invention can be implemented.

The electronic module or modules20may be arranged so they extend along the length of the retainer plate2. By way of electronic components, nonlimiting mention may be made of a microprocessor, an integrated circuit15, an electromagnetic compatibility circuit. A magnet17may also be present in the electronic module20.

With reference toFIGS. 1 to 6, without this being limiting, the electronic module20may comprise an integrated circuit15, not shown however inFIG. 1. InFIG. 2, this integrated circuit15is shown without a protective coating13, advantageously although not exclusively, made of an epoxy material, which protective coating13is shown inFIGS. 3 to 5.

InFIG. 2, the integrated circuit15is connected to tracks11by one or more connecting wires16. The connecting tracks11connect the integrated circuit15to other electronic components, for example one or more capacitors, an electromagnetic compatibility unit or other components referred to as surface-mount components. InFIG. 5, a magnet17is inserted in the electronic module20with portions of tracks11and of the integrated circuit15being bent back against the magnet17.

In the context of a method according to an aspect of the present invention, said at least one electronic component11,15or said at least one electrical-connection element4may be subjected to at least one electrical test. This may for example be performed, on the one hand, advantageously on the tracks11once they have been bent back onto the magnet17and, on the other hand, consecutively on the pins4. Respective test points18and18aon the tracks11and on the pins4are shown inFIG. 4, there being three points18for connection elements4and three points18afor the tracks11.

The method for producing the electronic module or modules20is performed on a metal retainer plate2, the electrical module or modules20being secured to the retainer plate2. The electrical test or tests are performed on the electronic module or modules20still secured to the retainer plate2.

The retainer plate2comprises at least a first securing bar5securing said at least one component11,15or electrical-connection element4of the or each electronic module20to the plate2. The retainer plate2also comprises at least one rough form6aof an insulating second securing bar6not contacting said at least one component11,15or electrical-connection element4. What is meant by a “rough form6aof an insulating second securing bar” is an incomplete insulating second securing bar such as an anchor stud or any arbitrary portion of a second securing bar that is shorter than the complete insulating second securing bar6. This rough form6aof second securing bar will be supplemented by an electrically insulating overmolded stud7as will be seen later.

“First bar” is to be considered as meaning a bar of a first type and “insulating second securing bar6” means a bar of the second type. Several first securing bars5and several insulating second securing bars6may coexist together.

The first securing bar or bars5serve to support one or more electronic components and/or one or more electrical-connection elements of each electronic module20in the process of being mounted without the envelope of the electronic module20having already been overmolded, the bar(s) alone providing the support for the components or elements.

The first securing bars5are secured firmly to the components or electrical-connection elements of the electronic module20, for example being made as one piece with this or these components or bonded or welded to this or these components. The first securing bars5are often made of metal and such a connection between components or electrical-connection elements and first securing bars5is electrically conducting.

The rough form or rough forms6aof insulating second connecting bars6have a free end pointing toward said at least one component11,15or element4, leaving a space between them. This free end of the rough form or rough forms6ais T-shaped given that it is intended to be surrounded by an overmolded bridge7and that a T-shape is propitious for anchoring the free end inside the overmolded bridge7.

Nonlimitingly, the rough form or rough forms6aof the insulating second securing bars6, as in the prior art, could serve to limit the overmolding of the envelope of the electronic module20and to help with the positioning of the overmolding of the envelope of the electronic module20, this overmolding being referred to in an aspect of the present invention as final overmolding. This role may optionally be performed in an aspect of the present invention by a fourth type of bar, referred to as envelope bars9and which will be detailed more fully later.

As will be seen later, an aspect of the present invention proposes to confer upon this or these rough form(s)6aof insulating second bars6a role of retaining and isolating certain zones borne by the electronic component or components11,15and/or the electrical-connection element or elements4of the or each electronic module20in the process of being mounted during the production of the electronic module20and, more particularly, for the conducting of one or more electrical test(s). This is achieved by an initial overmolding that forms a bridge overmolded on the rough form6aor each rough form6aof an insulating second securing bar.

It is the electronic component or components11,15or the electrical-connection element or elements4that are to be electrically tested by having at least one electrical-connection zone that is to be electrically tested. All the electronic components11,15or the electrical-connection elements4can be electrically tested, or just some of them.

InFIGS. 1 to 6, the retainer plate2is planar and rectangular, surrounding an electronic module20, although this is nonlimiting. There may be more than one electronic module20per plate2, for example, nonlimitingly, there may be 16, 24 or 32 electronic modules20per retainer plate2, and not necessarily an even number.

FIGS. 1 to 6show six first securing bars5, two for the tracks11near the integrated circuit15, two for the tracks11mid-way along the length of the retainer plate2, and two for the connecting pins4that the electronic module20comprises at a longitudinal end referred to as the rear end.

Two intermediate securing bars5care also provided between the connecting pins4of which there are three, and two intermediate securing bars5care provided between the tracks11of which there are three near the integrated circuit15, the intermediate securing bars5cbeing aligned with the associated first securing bars5.

Also shown are four rough forms6aor four insulating second securing bars6, depending on the degree of advancement of the method, with four rough forms6aof insulating second securing bars inFIGS. 1 to 2having inFIGS. 3 to 6become insulating second securing bars by having been supplemented respectively by an overmolded bridge7. In addition, there may also be bars of a third type and of a fourth type.

The bars of a third type are temporary-retention bars5bwhich temporarily come into contact with an internal element of the electronic module20when it is being assembled and temporarily hold this internal element during assembly. In the embodiment shown inFIGS. 1 to 6and notably inFIGS. 3 and 4, these temporary-retention bars5bhold in place the protective coating13that envelops the integrated circuit15.FIGS. 1 to 6show two temporary-retention bars5bper electronic module20on a retainer plate.

It is not necessary to secure these temporary-retention bars5bto the protective coating13because their action is merely temporary. The fact that the protective coating13is intercalated between two retaining bars5bleading from one respective longitudinal side of the retainer plate2may be enough to hold it in place by simple contact with the ends of the temporary-retention bars5b.Conversely, it is also possible to secure the protective coating13temporarily to each end of the temporary-retention bars5bby bonding or welding.

InFIG. 1, an integrated circuit has not yet been positioned at the front of the electronic module. InFIG. 2, the integrated circuit15is positioned at the front of the electronic module20but the protective coating13has not yet been installed and the temporary-retention bars5beach have a free end leaving between each of them and the portion of the integrated circuit15opposite enough space for the introduction of the protective coating13between the portion of integrated circuit15and their free ends.

InFIGS. 3 and 4, the protective coating13, while encasing the integrated circuits15, is inserted between the free ends of the two temporary-retention bars5b.

InFIG. 5, the tracks11initially extending in the plane of the retainer plate2, these tracks11connecting the integrated circuit15encased in the protective coating13, are bent through around 90° to form two bent-over portions spaced away from one another, these portions being bent in opposite directions from one another. A planar portion of the tracks11connects these two bent-over portions, running parallel to the plane of the retainer plate2. The bent-over portions and the planar portion of the tracks11surround a substantially cylindrical magnet17. One of the bent-over portions bears the integrated circuit15which is pressed against the magnet17.

As shown inFIG. 5, in this bent-over position, the free ends of the temporary-retention bars5bare clear of contact with the protective coating13and rendered once again free. Likewise, the first securing bars5lying at the level of the tracks11in the vicinity of the integrated circuit15have been cut off to allow the tracks11to be bent over.

InFIG. 5, the electronic module20is secured to the retainer plate2only by the insulating second securing bars6through the creation of overmolded bridges7connecting the free ends of the rough forms6aof insulating second bars6to the electronic module20, the overmolded bridges7forming part of a limited initial overmolding8.

The fourth type of bars groups together envelope bars9intended to come into contact with the final overmolding of the electronic module20forming a casing22for the electronic module20, this being shown inFIG. 6. InFIGS. 1 to 6, two envelope bars9are provided. The envelope bars9may be similar to the rough forms6aof insulating second securing bars6, having substantially the same length.

In the figures, an or each electronic module20may have three pins4which form electrical-connection elements. A first securing bar5connects the first and third pins4respectively to a length of the retainer plate2whereas two intermediate first securing bars5cconnect each of the first or third pins4respectively to the second pin. The same is true of the securing of the tracks11to one another at the rear of the electronic module20.

The majority of the first securing bars5and insulating second securing bars6may be positioned laterally with respect to the associated electronic module20, but these bars may also be positioned to the front or to the rear of the associated electronic module20.

According to an aspect of the present invention, prior to the final overmolding that forms the exterior envelope, there is performed a limited initial overmolding8at said at least one electrical-connection zone, thus surrounding a free-end portion of said at least one rough form6aof an insulating second securing bar6, by establishing a non-electrically-conducting overmolded bridge7in the space between the free-end portion of the rough form6aand said at least one electrical-connection zone. This is shown inFIG. 5.

Said at least one first securing bar5is then cut off from said at least one electronic component11,15or electrical-connection element4in order to electrically isolate said at least one electrical-connection zone. The overmolded bridge7remains the only thing securing said at least one electrical-connection zone to the retainer plate2via said at least one insulating second securing bar6thus formed. This overmolded bridge7, advantageously made from resin in a material that is electrically insulating, notably of epoxy, is effectively not a conductor of electricity, thus rendering the second securing bar6insulating.

The electronic component or components11,15and/or the electrical-connection element or elements4are then supported only by the limited initial overmolding8, possibly with an overmolded bridge7, the limited initial overmolding8connecting these components11,15and/or elements4to an insulating second securing bar6or to the insulating second securing bars6. This is the case inFIG. 5, in which all the first securing bars5have been cut off and are no longer visible or are visible only in terms of their portion that remains anchored to the retainer plate2.

If one or more of the first securing bars5are not secured to one or more electrical-connection zones, then it is possible for this or these first securing bar(s)5not to be cut off, as they do not prevent the electrical test or tests from being conducted. This or these first securing bar(s)5will, however, be cut off before or after the final overmolding of the exterior envelope of the electronic module20to form the casing22encapsulating the electronic module20.

After the limited initial overmolding8, one or more electronic component(s) secured to one or more electronic component(s) already present may also be added.

The insulating second securing bars6, formed of the rough forms6aand of a respective overmolded bridge7, which are shown inFIG. 5, perform a role of securing the tracks11to the retainer plate2after the cutting-off of the first securing bars5by holding these tracks11. These tracks11may therefore be electrically isolated even though they have not experienced a limited initial overmolding8but have profited from the limited initial overmolding8performed at other points on the electronic module20.

In the context of an aspect of the present invention, one or more electrical tests on the electrical-connection zone or zones is or are performed. Where possible, it is preferable for this or these electrical tests to take place with a planar retainer plate2. This is because this or these electrical tests are easier to perform on a retainer plate2that is planar, but may also be performed after potential bendings, in the case of some of the electrical tests, notably tests on one or more auxiliary component(s).

This may therefore be done prior to the final overmolding of the exterior envelope or after this final overmolding, still with the electronic component or components11,15or the electrical-connection element or elements4remaining secured to the insulating second securing bar or bars6by the overmolded bridges7that these bars6comprise.

In order to finalize the or each electronic module20, the exterior envelope may be overmolded and then the overmolded bridge7cut off level with the exterior envelope or protruding from the exterior envelope after the electrical test or tests, the exterior envelope forming the casing22of the electronic module20.

The overmolded bridge or bridges7that form part of a limited initial overmolding8encapsulating an electronic component11,15of the electronic module20, may be cut off as close as possible to the envelope of the electronic unit formed by the casing22in order to exhibit no roughness protruding beyond the envelope, namely flush with the envelope. The overmolded bridge or bridges7may, however, be cut off so that they protrude significantly from the envelope.

Conversely, when the limited initial overmolding8at least partially over part of its length encapsulates an electrical-connection element4such as one or more electronic connecting pins4projecting from the casing22, the limited initial overmolding8may be left projecting from the casing22to form an interface between the pins4and the casing22by encapsulating the pin or pins4outside the casing22over a portion of their length. This is particularly clearly visible inFIG. 7.

The presence of a limited initial overmolding8is recognizable by the cross section of the overmolded bridge7encapsulated by final overmolding substantially at the same level as or extending beyond the final overmolding, which means to say at least coming flush to the exterior envelope of the electronic module20having passed through it. The presence of a limited initial overmolding8is therefore visible on the electronic module20produced according to a method according to an aspect of the present invention. Likewise, a portion of the limited initial overmolding8projecting from the casing22may also be discernible. This can be seen on the connecting pins4on the outside of the casing22of the electronic module forming the exterior envelope of the electronic module20.

The final overmolding and the limited initial overmolding8may be made from the same material, for example epoxy resin, or in any event from an electrically insulating resin.

The steps of the production method are shown inFIGS. 1 to 6. Some of these steps are optional and inherent to the type of electronic module20that is to be produced. The same is true of the number of first securing bars5and of insulating second securing bars6. Envelope bars9and temporary-retention bars5bof the third and fourth types mentioned previously, as well as intermediate securing bars5cmay also be present in appropriate numbers.

FIG. 1shows a first step of the method according to an aspect of the invention whereby the tracks11of the electronic module20are secured to a frame2aof the retainer plate only by first securing bars5. The integrated circuit has not yet been introduced into the retainer plate2.

FIG. 2shows a step specific to the electronic module20illustrated inFIGS. 1 to 6with electrical connection of the integrated circuit15and of the tracks11by connecting wires16.FIG. 3shows a step of encapsulating the integrated circuit15in a protective coating13, third temporary securing bars5bflanking the protective coating13. Not all of the features of these two steps are essential to the implementation of the production method according to an aspect of the present invention; only the presence of the tracks11and of an integrated circuit15are generally common to most electronic modules20.

InFIGS. 1, 2 and 3, the free ends of the rough forms6aof insulating second securing bars not yet formed have not been encapsulated in a respective overmolded bridge7and these free ends lie at some distance from the components of the electronic module20.

FIG. 4shows a step of limited initial overmolding8of portions of components11and of electrical-connection elements4of the electronic module20with the creation of overmolded bridges7connecting these portions respectively to a rough form to form an insulating second securing bar6. The overmolded bridges7are made of an insulating material, ensuring insulation between the portions of the electronic module20that were initially overmolded and the rough forms of the insulating second securing bars6, which rough forms are no longer or barely visible in this figure as they have, for the most part, been overmolded in a respective overmolded bridge7.

FIG. 4also shows a step of cutting off the first securing bars5, stubs5aof cut first bars being visible in this figure. The same is true of the intermediate securing bars5c, for example between the electrical connecting pins4or between the tracks11.

FIG. 5shows a bending of the tracks11ending in the integrated circuit15around a magnet17. The third temporary securing bars5btherefore no longer play the role of securing to the protective coating13of the integrated circuit15of the electronic module20. This step is not essential to the implementation of the method according to an aspect of the present invention.

FIG. 6shows the final overmolding of the electronic module20, thereby forming its casing22. The overmolded bridges7may project from the casing22or lie flush with the casing22but will be cut off either level with the envelope of the casing22or such that they project from the casing22. The limited initial overmolding8may also project from the casing22partially flanking electrical-connection elements4external to the casing22, in this instance the connecting pins4. Fourth envelope bars9may locally limit the final overmolding that forms the casing22by coming into contact with it locally, something which is not essential in the context of an aspect of the invention.

In one preferred embodiment of the retainer, plate2, this retainer plate2may comprise a frame2asecured amongst other things to a respective end of the first securing bar or bars5and to the rough form or rough forms6aof insulating second securing bars6.

Said at least one first securing bar5and rough form6aof an insulating second securing bar6respectively have a free end at the opposite end to the end secured to the frame2a, the free end of the first securing bar or bars5being secured to an electronic component11,15or to an electrical-connection element4of the electronic module20.

The frame2amay have a writing zone2bon which information relating to the electronic module20may be written, for example, although not solely, information pertaining to the electrical tests.

The retainer plate2therefore via its frame2adelimits an internal opening used for positioning and securing electronic components11,15or other components that form part of one or more electronic module(s)20in the process of being produced.

In the case of the or each of the first securing bars5, the electronic component or components11,15or the electrical-connection element or elements4may be secured to the free end of this first securing bar5. This securing may be achieved by welding or bonding. In the case of the or each of the rough forms6aof the insulating second securing bars6, the electronic component or components11,15or the electrical-connection element or elements4may be positioned some distance away from this rough form6aof an insulating second securing bar6before the limited initial overmolding8, this limited initial overmolding8creating an overmolded bridge7.

The retainer plate2and said at least one first5and second6securing bars may be produced as a single piece by cutting or stamping from a piece of electrically conducting metal. The cutting may be cutting of any kind, for example waterjet cutting or laser cutting. It is also possible to obtain the retainer plate by 3-D printing, notably with the depositing of material and agglomeration using any means.

As an alternative, said at least one first securing bar5and at least one rough form6aof insulating second securing bar6may be bonded or welded to the retainer plate2.

As previously mentioned, the retainer plate2may be intended to support at least two electronic modules20, for example 16, 24 or 32 modules. At least one of the electronic components11,15or at least one of the electrical-connection elements4of each module20may be tested before or after a final overmolding of the envelope of the electronic module20that incorporates them, it being possible for this to be done while keeping all the modules20of the plate2secured to the retainer plate2.

Each electronic module20may comprise at least two zones that are to be electrically tested. In the figures, although this is nonlimiting, these may be the tracks11connecting the integrated circuit15to the rest of the electronic module20and one or more, connecting pin(s)4. An initial overmolding8limited to each zone that is to be tested or to a zone adjacent to the zone that is to be tested is therefore performed beforehand. The two zones may be overmolded initially and partially, and be so independently of one another.

An aspect of the invention also relates to an electronic module20comprising at least one electronic component11,15and at least one connecting pin4extending partially outside of the envelope of the electronic module20with an end portion connected inside the electronic module20, for example to at least one electronic component11,15.

With more particular reference toFIG. 7, such an electronic module20is produced and tested in accordance with a method as described hereinabove. The end portion of the connecting pin4connected to said at least one electronic component11,15may bear a limited initial overmolding8a portion of which projects from the casing22while encapsulating a portion of the pin or pins4, the pins4projecting from the casing22while being encapsulated on their adjacent portions by the portion of the overmolding which itself projects from the casing22. A cut off overmolded bridge7is visible as a cut-off portion7aon the envelope of the casing. This cut-off portion7alies flush at least with the envelope of the casing22, therefore lying at the same level as this envelope that forms the casing22or projecting externally from this envelope.

With more particular reference toFIG. 8, an aspect of the present invention also relates to a measurement sensor1comprising such an electronic module20. This measurement sensor1can be used in a motor vehicle as a sensor1that senses the speed or position of a drive shaft such as a camshaft or a crankshaft, notably being an inductive sensor1, although this is nonlimiting.

By way of example, this sensor1may more specifically be a sensor1that measures the speed or position of a drive shaft of the motor vehicle such as, for example, a camshaft or a crankshaft. The measurements taken by the sensor1are sent in the form of electrical signals to an electronic command/control unit of the vehicle which uses them to manage the engine parameters. This electronic command/control unit is known to those skilled in the art as an ECU which stands for “Electronic Control Unit”.

The sensor1is connected to the electronic control unit by three electric lines comprising a power supply, an output for sending electrical signals from the sensor1to the electronic control unit, and an electrical ground.

InFIG. 8, the pins4projecting from the casing22of the electronic module20have a curved shape differing from the planar shape shown inFIGS. 1 to 7, which is nonlimiting, these two modes being able to be employed as alternative.

In general, the sensor1comprises a base10and the electronic module20. The base10has a lug-shaped envelope12allowing the sensor1to be attached to a part of the vehicle such as, for example, the structure of the chassis or a wall, and a barrel14, made as one with the envelope12, designed to house the electronic module20within it. The electronic module20is configured to measure values of parameters that can be used by the electronic control unit to manage the operation of the vehicle engine.

For example, the electronic module20may be configured to measure the electromagnetic field in the vicinity of a target mounted on a drive shaft of the vehicle in order to determine the speed or position thereof. The electronic module20comprises a casing22of cylindrical shape, closed at one of its ends and inside which the electronic components previously mentioned with reference toFIGS. 1 to 6are inserted.

InFIG. 8, the electronic module20is discernible as having been produced using a method according to an aspect of the present invention insofar as it has one end of a portion of an overmolded bridge7acut off at least flush with the casing22and visible on the envelope thereof.