Packaging method and assembly packaged by the method

Abstract

The invention relates to a method for encapsulating an electronic board, said electronic board comprising at least one electronic component (3) and at least one connector (4) having at least one first portion (5) electrically connected to a printed circuit (2), and said method comprising at least: a first overmolding step of covering at least one portion of the printed circuit (2) and the electronic component (3) with a first covering layer (8); a first cooling step of cooling the first covering layer (8); a second overmolding step of covering the first covering layer (8) and the first portion (5) of the connector (4) with a second covering layer (9); and a second cooling step of cooling the second covering layer (9).

Description

Technical Field

[0001] The technical field of this invention is the packaging of electronic components.

[0002] This invention relates to a novel packaging method for electronic boards, and the packaged electronic boards produced by this method. Such electronic boards are specifically designed for potentially explosive environments, also known as ATEX environments, and are particularly suitable for the aerospace field, and more specifically, for aircraft fuel tanks. Background Technology

[0003] In certain environments, such as ATEX environments (whether liquid or gaseous), such as inside aircraft fuel tanks, especially in the aviation field, electronic components must be isolated and protected from the outside world. This is to protect them from risks from the external environment and to prevent them from posing any electrical risks to the outside world.

[0004] Among known protection technologies, one approach is to seal electronic components in sealed packaging. However, this solution is costly, bulky, and heavy. Furthermore, it is not reliable or safe under all operating conditions.

[0005] Another known protection technique is to encapsulate electronic components by embedding them in a protective coating.

[0006] In packaging solutions, a well-known technique is resin casting (also known as "encapsulation"), a process in which an electronic board is placed inside a housing and a low-viscosity resin is injected into the housing to completely cover the electronic board.

[0007] However, depending on the nature of the resin, air bubbles may become trapped in the resin, resulting in hot spots and other defects, and / or the resin may damage the solder joints on the electronic board.

[0008] Furthermore, the use of a housing limits the design flexibility of the package, while also increasing the cost, overall size, and weight of the solution.

[0009] Therefore, there is an urgent need for a packaging method for electronic components that is cost-effective, compact, and minimizes weight gain, while maintaining reliability and safety under all operating conditions. In particular, it is necessary to ensure that electronic components are electrically insulated from the external environment and protected from environmental moisture, chemical corrosion, and other harmful effects.

[0010] The encapsulation method must also include:

[0011] - Protect electronic components from shocks and vibrations;

[0012] - Ensure electrical insulation in the event of a malfunction or external event (such as a lightning strike);

[0013] - Provides thermal shock protection; and

[0014] - Make sure they are sealed;

[0015] Even if one of the electronic components malfunctions, burns, and / or explodes, the above requirements must still be met.

[0016] Furthermore, the packaging method must protect the surrounding environment of electronic components from potential hazards, especially electrical hazards. For example, the packaging structure must prevent potential arcs and / or sparks generated by electronic components from propagating outside the package.

[0017] The encapsulation method still needs to be implemented:

[0018] - Resistant to large temperature changes, especially from -55°C to +85°C;

[0019] - Adapt to the thermal expansion differences of electronic boards to prevent components from falling off;

[0020] - Ensure the electronic board is sealed; and

[0021] - To achieve heat dissipation for components;

[0022] - At the same time, ensure inherent safety.

[0023] Finally, the packaging method and the resulting packaged electronic board must be chemically compatible with fuel oil and hydraulic oil, and must not pose a risk of biological contamination to the aforementioned products. Summary of the Invention

[0024] Therefore, the present invention relates to a packaging method based on double overmolding, which is divided into two stages, wherein the two overlays are adhesive across the entire contact surface.

[0025] This invention relates to an electronic board packaging method, the electronic board comprising at least one printed circuit, the printed circuit including:

[0026] -At least one electronic component;

[0027] - At least one connector having a first portion that is electrically connected to a printed circuit.

[0028] In addition, the connector may have a second part that connects to the cable.

[0029] More specifically, the packaging method of the present invention includes at least:

[0030] -Initial preparation steps: Place at least one positioning element near the electronic board or through a port opened on the electronic board, and / or make at least one first fixing element abut against the electronic board;

[0031] - First overmolding step: Cover at least a portion of the printed circuit and electronic components with a first overlay (especially a hot melt adhesive composition);

[0032] - First cooling step: Cool the first coating layer, especially to allow it to cure.

[0033] - Second overmolding step: Cover the first cover layer and the first part of the connector with a second cover layer (especially a thermoplastic compound or thermoplastic elastomer);

[0034] - Second cooling step: Cool the second cover layer, especially to cure it, to ensure that the first cover layer and the second cover layer are directly bonded, especially by chemical bonding and / or mechanical anchoring.

[0035] In addition, the first cooling step may include removing the resulting electronic board from the first injection mold.

[0036] Similarly, the first cooling step may include removing the resulting electronic board from the second injection mold.

[0037] The packaging method of the present invention provides a solution to the problems discussed above. The first cover layer ensures that the printed circuit is protected and forms a sealed environment around the electronic components; in addition, the second cover layer provides excellent resistance to environmental stress, especially to environmental stress caused by hydrocarbon mixtures, sustainable aviation fuels, hydraulic oils, etc.

[0038] The packaging method of the present invention adopts double-layer encapsulation molding. In addition to double protection of electronic components, even if the first covering layer fails, the second covering layer can still ensure that the electronic board produced by the packaging method of the present invention is sealed and isolated from the external environment.

[0039] Therefore, the first capping layer can be more flexible and deformable than the second capping layer, while the second capping layer has greater rigidity and higher strength.

[0040] Therefore, for example, when an electronic board is struck by lightning, and an electric arc is generated at the electronic component even though the electronic components are embedded in the first cover layer, the second cover layer will form a second impenetrable barrier to prevent the electric arc from escaping from the encapsulation structure.

[0041] Furthermore, the first cover layer and the second cover layer are firmly bonded, preferably with chemical adhesive, to ensure a sealed interface between them.

[0042] In addition to the features described above, the packaging method of the present invention may also have one or more of the following additional features, which may be used individually or in any technically feasible combination:

[0043] - The first overmolding step includes injecting a first cover layer into a first injection mold under a first pressure, the first pressure being a maximum of 70 bar, particularly 50 bar, and more specifically 15 bar, to protect the integrity of the electronic components during the injection of the first cover layer;

[0044] - The first overmolding step includes injecting the first cover layer into the first injection mold at a first temperature, the first temperature being particularly higher than the melting point of the first cover layer, specifically, the first temperature being lower than 250°C, particularly lower than 200°C, more preferably lower than 180°C, in order to protect the integrity of the electronic components when injecting the first cover layer.

[0045] - The second overmolding step includes injecting the second overlay into a second injection mold under a second pressure, the second pressure being a maximum of 2000 bar, particularly 500 bar to 1500 bar, and more specifically 800 bar to 1200 bar;

[0046] -The second overmolding step includes injecting the second overlay into the second injection mold at a second temperature, which is particularly higher than the melting point and / or glass transition temperature of the second overlay;

[0047] - The first cover layer has a first thickness, particularly 0.5 mm to 5 mm, specifically 2 mm to 4 mm, the first thickness being particularly dependent on the peak insulation voltage to be met, and must be sufficient to ensure electrical insulation between the electronic device and the conductive external environment; and / or

[0048] The second cover layer has a second thickness, particularly 0.5 mm to 5 mm, specifically 2 mm to 4 mm. The second thickness depends in particular on the peak insulation voltage to be met and must be sufficient to ensure electrical insulation between the electronic board and the conductive external environment.

[0049] Furthermore, the packaging method of the present invention may also have at least one of the following features:

[0050] -The initial preparation steps are carried out before the first overcoating and molding step;

[0051] -Including an intermediate preparation step in which at least one second fastener abuts against the electronic board, particularly against the positioning element;

[0052] - Intermediate preparation steps are performed after the first cooling step and / or before the second overmolding step; and / or

[0053] - The second cooling step ensures that the first cover layer and the second cover layer are directly bonded, especially through chemical bonding and / or mechanical anchoring.

[0054] also:

[0055] - The first covering layer is a hot melt adhesive mixture, primarily containing polyamide;

[0056] - The second covering layer (9) is a thermoplastic blend or thermoplastic elastomer, particularly comprising mainly ether-amide block copolymers, polyethersulfone, polyetheretherketone and / or polyamides; and / or

[0057] The second cover layer may contain conductive fillers (especially carbon black), and the amount of these fillers should be sufficient to make the second cover layer conductive after curing.

[0058] Another aspect of the invention relates to an electronic board, the electronic board including a printed circuit, the printed circuit including at least one electronic component and at least one connector, the connector including at least one first portion electrically connected to the printed circuit and a second portion connected to a cable.

[0059] More specifically, the electronic board is manufactured by the above-described packaging method, wherein:

[0060] -At least part of the printed circuits and electronic components are covered by the first cover layer;

[0061] - The first cover layer and the first part of the connector are covered by the second cover layer.

[0062] Furthermore, the first cover layer and the second cover layer are connected to each other by direct adhesion, especially by chemical adhesion and / or mechanical anchoring.

[0063] According to one aspect of the invention, the first capping layer is a mixture mainly composed of polyamide, and / or the second capping layer is a composition mainly composed of ether-amide block copolymer, polyethersulfone, polyetheretherketone and / or polyamide.

[0064] With the help of this invention, electronic components can be reliably, repeatably, and durablely isolated from the external environment, and vice versa.

[0065] The packaging method of this invention is quick, simple, and can be automated, and it utilizes known double-overlay molding equipment. Furthermore, the packaging method of this invention reduces both direct and non-repetitive costs.

[0066] Finally, the packaging method according to the present invention is compatible with most electronic boards.

[0067] The packaged electronic board produced by the packaging method of this invention is lighter, smaller, and has fewer components than previous solutions, and has excellent resistance to vibration, temperature changes, and external environmental corrosion.

[0068] Furthermore, by selecting appropriate components for the second cover layer, the packaged electronic board produced by the packaging method of the present invention can be made compatible with all environments. Attached Figure Description

[0069] The invention will become clearer from the following detailed description, and its further features and advantages will also become apparent. The following detailed description includes exemplary embodiments and references the accompanying drawings (as non-limiting examples) to aid in understanding the invention, illustrating its implementation, and defining the invention where necessary, wherein:

[0070] Figure 1 A schematic diagram of a first example of an electronic board equipped with a connector connected to a cable is shown;

[0071] Figure 2 An example according to the present invention is shown, encapsulated within a first cover layer. Figure 1 A schematic diagram of the electronic board shown;

[0072] Figure 3 This illustrates the invention, encapsulated within a second cover layer. Figure 2 A schematic diagram of the electronic board shown;

[0073] Figure 4 A schematic diagram of a second example of an electronic board equipped with a connector connected to a cable is shown;

[0074] Figure 5 This illustrates the invention, which is encapsulated within a first cover layer. Figure 4 A schematic diagram of the electronic board shown;

[0075] Figure 6 This illustrates the invention, encapsulated within a second cover layer. Figure 5 A schematic diagram of the electronic board shown;

[0076] Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 , Figure 12 An example of the dual-overlay molding and packaging method of the present invention is illustrated schematically; and

[0077] Figure 13 , Figure 14 The schematic illustration shows the initial steps of another example of the double-overlay molding and packaging method of the present invention. Detailed Implementation

[0078] It should be noted that in the accompanying drawings, structural and / or functional elements common to various embodiments may be referred to by the same reference numerals. Therefore, unless otherwise stated, such elements have the same structure, dimensions, and material properties.

[0079] Figures 1 to 6 Two examples of the electronic board 1 of the present invention are illustrated schematically.

[0080] More specifically, such as Figure 1and Figure 4 As shown, the electronic board 1 also includes a printed circuit 2, which includes at least one electronic component 3 mounted on the surface of the printed circuit 2.

[0081] The electronic board 1 also includes at least one connector 4, which has a first part 5 and a second part 6, the first part 5 being electrically connected to the printed circuit 2 and the second part 6 being connected to the cable 7.

[0082] Cable 7 can be rigid or flexible and can be covered with a sheath, such as a sheath made of polytetrafluoroethylene (PTFE).

[0083] Connector 4 is used, for example, to power the electronic board 1 and / or to enable electrical signal exchange between the electronic board 1 and other devices, such as devices connected to cable 7.

[0084] In one specific embodiment, the connector 4 and the cable 7 may be an integral structure.

[0085] The present invention relates to a packaging method for an electronic board 1, and the packaged electronic board 1 obtained by the method.

[0086] The encapsulation method of the present invention includes at least a first overmolding step, in which at least a portion of the printed circuit 2 and the electronic components 3 are covered by a first cover layer 8 (especially hot melt adhesive). Thus, at least a portion of the printed circuit 2 and the electronic components 3 are encapsulated within the first cover layer 8.

[0087] The first covering layer 8 constitutes the first overlay molding layer.

[0088] The first overmolding step of the encapsulation method of the present invention is performed in the first injection mold, for example, using a conventional overmolding process.

[0089] Specifically, the first overmolding step of the encapsulation method of the present invention involves injecting the first cover layer 8 into a first injection mold under a first pressure P1. The maximum value of the first pressure P1 is particularly 70 bar, specifically 50 bar, and more specifically 15 bar.

[0090] Furthermore, the first overmolding step of the encapsulation method of the present invention involves injecting the first cover layer 8 into a first injection mold at a first temperature T1. The first temperature T1 is particularly higher than the melting point of the first cover layer 8, but the first temperature T1 is lower than 250°C, particularly lower than 200°C, and more specifically lower than 180°C.

[0091] The first covering layer 8 (especially the hot melt adhesive mixture) has a first thickness E1, which is particularly between 0.5 mm and 5 mm, and more specifically between 2 mm and 4 mm.

[0092] Furthermore, the encapsulation method of the present invention includes at least a first cooling step, in which the first cover layer 8 is cooled to cure the first cover layer 8.

[0093] Figure 2 and Figure 5 They were shown schematically respectively. Figure 1 and Figure 3 The electronic board 1 shown is encapsulated within the first cover layer 8 after a first cooling step according to the encapsulation method of the present invention.

[0094] According to the first example embodiment (e.g.) Figure 2 As shown), the first portion 5 of connector 4 may remain outside the first cover layer 8. According to a second example embodiment (such as...), Figure 5 As shown), the first part 5 of connector 4 can be covered by the first cover layer 8, and thus also encapsulated.

[0095] The electronic board 1, which is partially or completely encapsulated within the first cover layer 8, can then be removed from the first injection mold.

[0096] Furthermore, the encapsulation method of the present invention includes at least a second overmolding step, in which the first cover layer 8 and the first portion 5 of the connector 4 are covered by a second cover layer 9 (especially a thermoplastic material or thermoplastic elastomer). Thus, the first cover layer 8 and the first portion 5 of the connector 4 are encapsulated within the second cover layer 9.

[0097] In the second overmolding step, even if the first part 5 of the connector 4 is located outside the first cover layer 8 in the first example embodiment, it will be encapsulated in the second cover layer 9.

[0098] The second covering layer 9 constitutes the second overlay molding layer.

[0099] The second overmolding step of the encapsulation method of the present invention is performed in a second injection mold, which is in particular fitted onto the outside of the component obtained in the first cooling step, for example, using a conventional overmolding process.

[0100] Specifically, the second overmolding step of the encapsulation method of the present invention includes injecting the second cover layer 9 into a second injection mold under a second pressure P2. The maximum value of the second pressure P2 is particularly 2000 bar, specifically between 500 bar and 1500 bar, and more specifically between 800 bar and 1200 bar.

[0101] Furthermore, the second overmolding step of the encapsulation method of the present invention involves injecting the first cover layer 8 into a second injection mold at a second temperature T2. The second temperature T2 is particularly higher than the melting point and / or glass transition temperature of the second cover layer 9.

[0102] Specifically, if the second covering layer 9 is a thermoplastic material or a thermoplastic elastomer, then the second temperature T2 is particularly higher than:

[0103] The melting point of the second covering layer 9 when it is in a semi-crystalline state; and / or

[0104] The second capping layer 9 represents the glass transition temperature when the material is amorphous.

[0105] The second covering layer 9 (especially a thermoplastic material or a thermoplastic elastomer mixture) has a second thickness E2, which is 0.5 mm to 5 mm, especially 2 mm to 4 mm.

[0106] The values ​​for the first thickness E1 and the second thickness E2 can be, for example, 3 mm. In the following text, the general value XX mm will be used to refer to these thicknesses.

[0107] Based on these dimensions, it can be understood that not only is the electronic component 3 covered by the first covering layer 8, but the first covering layer 8 itself is also covered by the second covering layer 9. Of course, "covering" here means "complete coverage".

[0108] Similarly, the surface of electronic component 3 is covered by a first covering layer 8 with a thickness of at least XX millimeters and a second covering layer 9 with a thickness of at least XX millimeters.

[0109] The first cover layer 8 and the second cover layer 9, both with a thickness of at least XX millimeters, can conform to the outline of the electronic board 1 and have a basically uniform thickness on the electronic board 1.

[0110] As a supplement or alternative, the first cover layer 8 and the second cover layer 9, both with a thickness of at least XX mm, may be in block form (as shown in the figure), with variable thickness, but not less than XX mm.

[0111] It can also be set as follows: the first cover layer 8 basically fits the outline of the electronic board 1, and the second cover layer 9 is block-shaped, the external shape of which will determine the shape of the finished product.

[0112] The second cover layer 9 can also be molded with fasteners for mounting the packaged electronic board 1 to the usage position.

[0113] Such fasteners may be integrally molded with the second cover layer 9, or partially embedded in the second cover layer 9 during the second overmolding step.

[0114] In the second overmolding step, the first cover layer 8 protects the electronic components 3 from the molding pressure.

[0115] The encapsulation method of the present invention further includes at least a second cooling step, in which the second cover layer 9 is cooled, and thus the second cover layer 9 is cured.

[0116] In the second cooling step, the second cover layer 9 is ensured to be directly bonded to the first cover layer 8, especially through chemical bonding and / or mechanical anchoring, to achieve complete bonding and / or perfect sealing between the first cover layer 8 and the second cover layer 9.

[0117] Figure 3 and Figure 6 The images show the contents of the second cover layer 9 after the second step of the encapsulation method of the present invention is completed. Figure 2 , Figure 5 A schematic diagram of electronic board 1 in the diagram.

[0118] The electronic board 1, which is encapsulated entirely or partially within the first cover layer 8 and the second cover layer 9, can then be removed from the second injection mold.

[0119] In this instruction manual:

[0120] - The term "direct bonding" should be understood as the adhesion mechanism between the contact surfaces of two materials (here, the first cover layer 8 and the second cover layer 9) without the addition of a third intermediate material;

[0121] - The term "chemical adhesion" should be understood as a mechanism by which the contact surfaces of two materials (here referring to the first coating 8 and the second coating 9) adhere to each other through molecular contact and the formation of chemical bonds (e.g., covalent bonds between the contact surfaces) between atoms, molecules and / or functional groups.

[0122] - The term "mechanical anchoring" should be understood as a mechanism for adhesion between two materials (here, the first coating 8 and the second coating 9) on the contact surface, wherein one material is in liquid form and contacts the surface of the other material and penetrates into the pores of the other material before drying and / or hardening (curing) to ensure mechanical adhesion between the two materials;

[0123] - The term "mechanical anchoring" must also be understood as a mechanism for the adhesion of two materials (here, the first coating 8 and the second coating 9) at their contact surfaces, one of which contains cavities that are designed to be filled with the other material to ensure the fixation between the two materials and to prevent the two materials from loosening after cooling and curing.

[0124] - The term "hot melt adhesive" should be understood to encompass all types of hot melt adhesives, abbreviated as "HMA," which constitutes a category of thermoplastic adhesives;

[0125] - The term "thermoplastic mixture" must also be understood to include all polymers or polymer mixtures that may reversibly soften or melt upon temperature increase; and

[0126] - The term "thermoplastic elastomer composition" should be understood to refer to all types of copolymers or polymer mixtures that combine the properties of thermoplastics (i.e., materials that soften or melt upon heating and harden upon cooling) and elastomers.

[0127] The hot melt adhesive composition and the thermoplastic / thermoplastic elastomer composition may be selected to meet one or more of the following conditions:

[0128] - In its liquid state, the hot melt adhesive composition has a low viscosity, enabling:

[0129] - On the one hand, in the first overmolding step, it can penetrate into the area around electronic components without generating bubbles;

[0130] - On the other hand, injection is performed under low pressure to maintain the integrity of the electronic components covered by the overmolding material;

[0131] - Hot melt adhesive is an electrical insulator;

[0132] - Hot melt adhesive compositions cannot be capacitively coupled;

[0133] - The hot melt adhesive composition is flame retardant;

[0134] - Hot melt adhesive compositions must not be thermal insulators to facilitate heat dissipation of electronic components;

[0135] - Hot melt adhesive compositions can be elastically deformed, making them particularly suitable for the thermal expansion of electronic components;

[0136] - Hot melt adhesive is non-corrosive, and in particular, avoids chemical damage to electronic components;

[0137] - Thermoplastic / thermoplastic elastomer compositions must be adapted to the environment in which the electronic board is used, without polluting and / or damaging the environment, and vice versa;

[0138] - Hot melt adhesives and thermoplastic / thermoplastic elastomer materials must be compatible to avoid cross-contamination and / or degradation, especially to achieve the best possible adhesion at their interfaces (more specifically through chemical bonding and / or mechanical anchoring) to prevent fluid from seeping between the first cover layer 8 and the second cover layer 9;

[0139] - Hot melt adhesive compositions and thermoplastic / thermoplastic elastomer compositions comply with the EU REACH regulation, an acronym for "Registration, Evaluation, Authorisation of Chemicals".

[0140] According to one embodiment of the present invention, the hot melt adhesive composition may be a composition mainly comprising polyamide (PA); the thermoplastic / thermoplastic elastomer composition may be a composition mainly comprising ether-amide block copolymer (TPE-A). Thus, the hot melt adhesive composition and the polyamide groups in the thermoplastic / thermoplastic elastomer composition form a chemical bond between the first capping layer 8 and the second capping layer 9.

[0141] It should be noted that the general formula for the ether-amide block copolymer TPE-A is:

[0142] HO-(CO-PA-CO-O-PE-O)nH

[0143] in:

[0144] -PA is polyamide; and

[0145] -PE stands for polyether.

[0146] The thermoplastic elastomer constituting the second cover layer 9 can absorb shock and vibration; in addition, when subjected to mechanical load, the thermoplastic elastomer constituting the second cover layer 9 can deform without damaging the cable 7.

[0147] According to another embodiment of the invention, the thermoplastic / thermoplastic elastomer composition may be a thermoplastic composition primarily comprising polyamide (PA). In this other embodiment of the invention, the polyamide (PA) constituting the second cover layer 9 is more cost-effective and more rigid. Furthermore, it may also have additional functions, such as areas for securing the packaging to a support.

[0148] According to another embodiment of the present invention, the second cover layer 9 is made of a thermoplastic composition mainly comprising polyethersulfone (PES) and / or polyether ether ketone (PEEK), thereby giving the second cover layer 9 excellent mechanical strength and chemical stability.

[0149] According to yet another embodiment, the thermoplastic / thermoplastic elastomer composition does not contain fillers that could make it conductive, thereby enhancing the electrical insulation performance between the printed circuit 2 and the environment in which it is used.

[0150] According to another embodiment of the present invention, the thermoplastic / thermoplastic elastomer composition may contain a conductive filler (e.g., carbon black) in an amount sufficient to make the thermoplastic / thermoplastic elastomer composition conductive after curing. Thus, the thermoplastic / thermoplastic elastomer composition facilitates the dissipation of electrostatic charges.

[0151] The first and second overmolding steps of this invention employ known molds and processes. In both the first and second overmolding steps, the position of the component to be overmolded must be recorded. Furthermore, the component to be overmolded must, in particular, be kept centered in the first injection mold and / or the second injection mold.

[0152] Therefore, the positioning or fixing of the component to be overmolded can be achieved through the following components:

[0153] - Positioning components: used for high-precision positioning of components to be packaged; and

[0154] - Fixtures: Used to secure the components to be packaged during the packaging process.

[0155] The positioning element is preferably made of metal, especially because it can withstand the temperatures encountered during the packaging process. Furthermore, metal positioning elements are also suitable for use as electrical connectors.

[0156] In addition, the positioning element can be detachable.

[0157] According to one specific embodiment, if connector 4 has sufficient rigidity, it can also serve as a positioning element and / or a fixing element.

[0158] Combination Figures 7 to 14 Two embodiments of the encapsulation method of the present invention are described below.

[0159] For the sake of simplicity, electronic component 3 is not shown in the figure, and the shapes of the various components to be packaged are also highly simplified schematically.

[0160] The packaging method of the present invention may include an initial preparation step (especially such as...) Figure 7 As shown), in this step, at least one positioning element 10 (especially at least one insert 10) is disposed near the electronic board 1. In one specific embodiment, the positioning element 10 is spaced apart from the electronic board 1.

[0161] according to Figure 13 , Figure 14 In another embodiment shown, the positioning member 10 may also be disposed in the through hole 13 opened in the area on the electronic board 1 where no electronic component 3 is installed. Figure 13 The electronic board 1 before the positioning element 10 is placed is shown. Figure 14 The electronic board 1 is shown after the positioning element 10 has been placed. It should be noted that the subsequent packaging steps of this alternative are similar to those of the first alternative; therefore, they will not be repeated here. Please refer to [link to relevant documentation]. Figures 8 to 12 .

[0162] According to this other embodiment, such a positioning element 10 can also be used as a fixing point (especially by threaded connection) to fix to a support. For this purpose, the positioning element may, for example, have a longitudinal port, which may be threaded or unthreaded.

[0163] In the double-overlay molding process, the height of the positioning component 10 can be basically equal to the height of the electronic board 1 at the end of the encapsulation method, that is, the height after the first cover layer 8 and the second cover layer 9 are covered.

[0164] The initial preparation steps may also include placing at least one first fixing member 11a (in particular at least one centering device 11a). In addition, the first fixing member 11a may abut against the electronic board 1 (in particular different surfaces of the electronic board 1) to fix the electronic board 1 in the first injection mold.

[0165] Alternatively, the first fixing member 11a can be directly disposed in the first injection mold.

[0166] Such a first fastener 11a can in particular abut against a blank area of ​​the electronic board 1, that is, an area without electronic components 3.

[0167] The packaging method of the present invention may include a first positioning step, in which the component obtained at the end of the initial preparation step is loaded into a first injection mold, and the positioning member 10 is fixed to the first fixing member 11a.

[0168] Therefore, in the first overmolding step of the encapsulation method of the present invention, the first cover layer 8 (especially a hot melt adhesive composition) is injected (especially in liquid form) into the first injection mold.

[0169] The first injection mold is designed to cover at least a portion of the printed circuit 2 and the electronic components 3 by overmolding the first cover layer 8.

[0170] All or part of the connector 4 may also be overmolded by the first cover layer 8, although this is not necessary in the first overmolding step.

[0171] exist Figure 8 In the example, the entire printed circuit 2 is overmolded and covered, although in reality only the electronic components 3 need to be covered and encapsulated within the first cover layer 8.

[0172] After the first cooling step, the first covering layer 8 has cooled and solidified, at which point the first fastener 11a can be removed, exposing at least one hollow cavity (well-like structure 12), especially as... Figure 9 As shown.

[0173] Before the second overmolding step, the encapsulation method of the present invention may include at least one intermediate preparation step in which at least one second fixing member 11b (in particular at least one centering device 11b) is placed; the second fixing member 11b may abut against the electronic board 1 (in particular different surfaces of the electronic board 1) to fix the electronic board 1 in the second injection mold.

[0174] Alternatively, the second fastener 11b can be directly installed inside the first injection mold.

[0175] According to one specific embodiment, the second fixing member 11b is disposed on the positioning member 10 extending from the outside of the first covering layer 8, such as... Figure 10 As shown.

[0176] The packaging method of the present invention may include a second positioning step, in which the component obtained in the intermediate preparation step is loaded into a second injection mold, and the second fixing member 11b (especially integrally formed with the second injection mold) is fixed.

[0177] Therefore, in the second overmolding step of the encapsulation method of the present invention, a liquid second covering layer 9 (especially a thermoplastic material or a thermoplastic elastomer composition) is injected into a second injection mold.

[0178] The second injection mold is designed to allow the second cover layer 9 to be molded over and cover the first cover layer 8 (especially to cover the entire layer).

[0179] Furthermore, regardless of whether the first part 5 of connector 4 is covered by the first cover layer 8, it must be covered by the second cover layer 9 to protect the connection between connector 4 and electronic board 1 and to ensure the sealing of components at connector 4, such as... Figure 11 As shown.

[0180] Therefore, the second covering layer 9 needs to be flexible enough to deform under mechanical loads to fit the cable 7.

[0181] In the second overcoating step, the well-shaped structure 12 is filled and overcoated by the second covering layer 9.

[0182] The positioning element 10 can be used as a fixing point (especially by threaded connection) to fix to the support. In addition, the positioning element 10 can also be used as an anti-creep ring.

[0183] In some cases, the cable 7 connected to the connector 4 may be covered by a sheath, especially a sheath made of polytetrafluoroethylene (PTFE), and the first cover layer 8 and / or the second cover layer 9 may be difficult to attach to the sheath.

[0184] To ensure that the electronic board 1 is sealed at the interface with the sheath, the encapsulation method of the present invention may include a sealing step in which a sealing sleeve (especially by heat sealing) is connected to the interface between the sheath and the first cover layer 8 and / or the second cover layer 9.

[0185] As a supplement or alternative, the sheath is surface-treated during the sealing step to improve the adhesion of the first cover layer 8 and / or the second cover layer 9.

[0186] In one specific embodiment, the encapsulation method of the present invention is configured as follows:

[0187] - Multiple positioning elements 10, especially multiple inserts 10;

[0188] - Multiple first fasteners 11a, particularly multiple centering devices 11a; and / or

[0189] - Multiple second fasteners 11b, especially multiple centering devices 11b.

[0190] - In the encapsulation method of the present invention, the number of second fixing members 11b is less than or equal to the number of positioning members 10.

[0191] - The electronic board 1 includes a printed circuit 2 and at least one connector 4. After being packaged by the packaging method of the present invention, at least a portion of the printed circuit 2 and the electronic components 3 are encapsulated in a first cover layer 8, and the entire first cover layer 8 and the first portion 5 of the connector 4 are encapsulated in a second cover layer 9.

[0192] The encapsulation method of the present invention ensures a strong bond and complete seal between the first cover layer 8 and the second cover layer 9, for example, through chemical bonding or mechanical anchoring.

[0193] In various embodiments, the printed circuit 2 may include a plurality of electronic components 3 mounted on the surface of the printed circuit 2. According to the invention, in this configuration, all electronic components 3 are covered by a first cover layer 8 in the first overmolding step.

[0194] The electronic board 1 obtained by the packaging method of the present invention is particularly suitable for use in aircraft fuel tanks and / or ATEX environments.

[0195] Although described by way of various examples, alternatives and embodiments, the packaging method of the present invention and the resulting electronic board 1 include various alternatives, modifications and improvements that are obvious to those skilled in the art. It should be understood that such alternatives, modifications and improvements are all within the scope of protection of the present invention.

Claims

1. A method for packaging an electronic board (1), the electronic board (1) comprising at least one printed circuit (2), the printed circuit (2) comprising: -At least one electronic component (3); as well as - At least one connector (4), the connector (4) having at least one first portion (5) electrically connected to the printed circuit (2); The method is characterized by comprising at least: - Initial preparation steps: Place at least one positioning element (10) near the electronic board (1) or through the port (13) opened on the electronic board (1), and / or make at least one first fixing element (11a) abut against the electronic board (1). - First overlay molding step: Cover at least a portion of the printed circuit (2) and electronic components (3) with the first cover layer (8); - First cooling step: Cooling the first covering layer (8); - Second overmolding step: Cover the first cover layer (8) and the first part (5) of the connector (4) with the second cover layer (9); - Second cooling step: Cool the second cover layer (9).

2. The packaging method according to claim 1, characterized in that, The first overmolding step includes injecting the first cover layer (8) into a first injection mold under a first pressure (P1), the first pressure (P1) being particularly 0 bar to 70 bar, specifically 0 bar to 50 bar, more specifically 0 bar to 15 bar; and / or injecting it at a first temperature (T1), the first temperature (T1) being particularly higher than the melting point of the first cover layer (8).

3. The packaging method according to any one of the preceding claims, characterized in that, The second overmolding step includes injecting the second cover layer (9) into a second injection mold under a second pressure (P2), the second pressure (P2) being at a maximum of 2000 bar, particularly 500 bar to 1500 bar, more specifically 800 bar to 1200 bar; and / or injecting at a second temperature (T2), the second temperature (T2) being particularly higher than the melting point and / or glass transition temperature of the second cover layer (9).

4. The packaging method according to any one of the preceding claims, characterized in that, The first cover layer (8) has a first thickness (E1), particularly 0.5 mm to 5 mm, specifically 2 mm to 4 mm; and / or the second cover layer (9) has a second thickness (E2), particularly 0.5 mm to 5 mm, specifically 2 mm to 4 mm.

5. The packaging method according to any one of the preceding claims, characterized in that, The initial preparation steps are performed before the first overmolding step.

6. The packaging method according to any one of the preceding claims, characterized in that, It also includes an intermediate preparation step in which at least one second fastener (11b) is brought into contact with the electronic board (1), particularly with the positioning member (10).

7. The packaging method according to claim 6, characterized in that, The intermediate preparation steps are performed after the first cooling step and / or before the second overmolding step.

8. The packaging method according to any one of the preceding claims, characterized in that, The second cooling step ensures that the first cover layer (8) and the second cover layer (9) are directly bonded, especially through chemical bonding and / or mechanical anchoring.

9. The packaging method according to any one of the preceding claims, characterized in that, The first cover layer (8) is a hot melt adhesive composition, particularly mainly comprising polyamide (PA); and / or the second cover layer (9) is a thermoplastic composition or thermoplastic elastomer, particularly mainly comprising ether-amide block copolymer (TPE-A), polyethersulfone (PES), polyether ether ketone (PEEK) and / or polyamide (PA).

10. The packaging method according to any one of the preceding claims, characterized in that, The second cover layer (9) contains conductive filler, especially carbon black.

11. An electronic board (1) comprising a printed circuit (2), said printed circuit (2) comprising: -At least one electronic component (3); - At least one connector (4), said connector (4) having at least one first portion (5) electrically connected to the printed circuit (2), and A second part (6) connected to the cable (7); The electronic board (1) is characterized in that it is manufactured by the packaging method described in any one of the preceding claims, and: - The positioning element (10) is located near the electronic board (1), and / or at least one first fixing element (11a) abuts against the electronic board (1). -At least a portion of the printed circuit (2) and the electronic components (3) are covered by the first cover layer (8); as well as - The first cover layer (8) and the first part (5) of the connector (4) are covered by the second cover layer (9).

12. The electronic board (1) according to claim 11, characterized in that, The first cover layer (8) and the second cover layer (9) are connected to each other by direct adhesion, especially by chemical adhesion and / or mechanical anchoring.

13. The electronic board (1) according to claim 11 or 12, characterized in that, The first cover layer (8) is a composition mainly comprising polyamide; and / or the second cover layer (9) is a composition mainly comprising ether-amide block copolymer (TPE-A), polyethersulfone (PES), polyether ether ketone (PEEK) and / or polyamide (PA).

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