Manufacturing method and electronic configuration for designing an electronic device comprising a non-flat layered item having a non-flat electronic circuit

Abstract

A method for manufacturing an electronic device comprising a non-planar layered item (10) having a non-planar electronic circuit (20) on top of it, wherein the planar electronic circuit (20') is designed to become a non-planar electronic circuit (20) after a molding process, and for each surface mount component (22), an optimal adhesive distribution is defined by determining a first load induced on the bond between the surface mount component and the planar layered item, and a second load induced on the portion of a conductive track located around a local curing area of ​​the planar layered item to which at least one adhesive is applied, wherein the optimal adhesive distribution is selected to obtain a bond having a first fracture threshold greater than the first load and to produce a second load below a predetermined second fracture threshold of the conductive track,

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an electronic device including a non-flat electronic circuit on a non-flat laminar item.

[0002] The non-flat electronic circuit includes at least conductive tracks connecting at least one surface-mounted component (or surface-mounted part) attached to the non-flat laminar item via at least one adhesive providing a known adhesive force per unit area.

[0003] The present invention also targets an electronic device obtained from the above method.

Background Art

[0004] It is already known that an electronic device including a non-flat laminar item having a flat electronic circuit thereon can be obtained by a forming process from a flat laminar item having a flat electronic circuit thereon. Also, it is known to overmold a non-flat laminar item with a non-flat electronic circuit having structural elements by an overmolding process.

[0005] During the forming process of a flat laminar item into a non-flat laminar item, it undergoes local curvature (or curvature) and stretching, which may cause separation of one or several of the surface-mounted components from the surface of the non-flat laminar item, or interruption on some of the conductive tracks, leading to malfunction of the non-flat electronic circuit.

[0006] References EP3499393A1, EP3664586A1, and FR3127861A1 describe different methods for manufacturing non-planar layered items having non-planar electronic circuits on them.

[0007] Furthermore, it is known that non-planar layered items can be overmolded in non-planar electronic circuits that have structural elements using an overmolding process.

[0008] During the overmolding process, the molding resin flows within the mold containing at least a portion of the non-planar electronic circuitry before curing. The fluid material flowing around the surface mount components pushes against them, creating shear loads, which can cause one or more surface mount components to separate from the surface of the non-planar layered item, potentially leading to malfunction of the non-planar electronic circuitry. [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention solves the above and other problems. [Means for solving the problem]

[0010] <Disclosure of the Invention> According to a first aspect, the present invention relates to a method for manufacturing an electronic device comprising a non-planar layered item having a non-planar electronic circuit thereon, as defined in claim 1.

[0011] Non-flat layered items are thin sheets that are molded to have a three-dimensional geometric shape, including curvature, such as a curvature along one axis, like zero Gaussian curvature, or curvature along two orthogonal axes, like positive or negative Gaussian curvature.

[0012] Typically, such non-flat items are made from thermoplastic materials that become deformable when heated, allowing them to be molded into their non-flat shape.

[0013] Non-planar electronic circuits are supported on non-planar layered items, typically printed circuits, and include at least a conductive track and at least one surface-mount component.

[0014] Surface mount components are attached to or electrically connected to non-laminar items (or non-planar laminar items) and / or conductive tracks via at least one adhesive having a known adhesive strength per unit area.

[0015] The adhesive may be a conductive adhesive, providing adhesion to surface-mount components and also providing electrical contact between the electrical contacts of the surface-mount components and the conductive tracks. Solder material is considered to provide both of these functions and therefore can be considered an adhesive.

[0016] Optionally, the dimensions of each surface mount component are known, including at least the dimensions of its base surface facing a non-planar layered item.

[0017] Adhesives may be placed between surface-mount components and non-planar layered items, between surface-mount components and non-planar conductive tracks, on the periphery of surface-mount components, and / or to completely cover surface-mount components that are encapsulated within an adhesion shell. Any combination of these adhesive distributions is intended using the same or different types of adhesives with varying adhesive strengths per unit area.

[0018] Typically, the adhesive automatically deposits as droplets, and the spacing and position between droplets are known. The spacing and position between droplets determine the adhesive distribution of at least one adhesive. The viscosity of the adhesive also determines the size of each droplet and may be known as part of the distribution parameters.

[0019] Typically, each surface mount component has a bottom surface facing the surface of a non-flat layered item, preferably a flat bottom surface. A predetermined number of adhesive droplets having a predetermined distribution are placed between the bottom surface and the surface mount component, and between the surface of the non-flat layered item or conductive track, to provide adhesion. Alternatively, adhesive droplets are placed around the surface mount component and / or completely cover the surface mount component, encapsulating it within an adhesive shell.

[0020] Another known solution for distributing adhesive is to use a stencil, typically a metal plate with openings where the adhesive should be applied. The stencil is placed over a flat layered item, and the adhesive is distributed onto the stencil, reaching the flat layered item only in predetermined locations through the openings. The stencil is then removed, and the surface mount component is placed on the flat layered item with the adhesive deposited on top.

[0021] The proposed manufacturing method is: A step of defining (or specifying / define) the geometric shape and dimensions of a flat layered item suitable for being deformed into a non-flat layered item by a molding process, A step of determining local bending and / or stretching on a flat layered item during the process of forming it into a non-flat layered item, Includes.

[0022] According to the above, starting from a predefined shape of a non-flat layered item, a shape of a flat layered item is defined that can generate the non-flat layered item through a molding process, and it is determined which local bending and / or stretching occurs on each region of the flat layered item during the molding process to become the non-flat layered item.

[0023] The geometric shape and dimensions of a flat layered item can be obtained based on the simulation of the forming process. 3D design software and forming simulation software can be used. Such simulations also provide information on the local bending and / or stretching that each region of the flat layered item undergoes during its forming into a non-flat layered item.

[0024] Alternatively, the definition of the shape of a flat layered item can be obtained through an empirical process using a sample, for example, a sample of a flat layered item with a known pattern drawn on it, which is deformed in a measurable manner after the forming process.

[0025] This forming process, also known as thermoforming, involves heating the flat layered item so that it becomes plastically deformable and forming the flat layered item into a non-flat layered item while the flat layered item is still hot in its plastic state. The forming can be achieved using a mold. When the non-flat layered item is cooled to room temperature, it loses its deformable state and as a result, retains its non-flat shape.

[0026] The process of forming a flat layered item into a non-flat layered item has known limitations in the maximum stretching and curvature of the flat layered item. Accordingly, a non-layered item (or, non-flat layered item) is designed taking into account the said known limitations such that such a non-flat layered item is obtained through the forming process of the flat layered item. <"0000093"> Surface mount components are attached to the flat layered item prior to the forming process by applying at least one adhesive, and subsequently, the flat layered item is formed into a non-flat layered item, causing local bending and / or stretching in at least some of its regions.

[0028] The proposed manufacturing method further defines function-determined locations (or function determined locations) on non-flat layered items for some of the surface-mounted components, identifies precursor locations on the flat layered item that will become function-determined locations after the forming process, and positions the surface-mounted components on the precursor locations, and positions each of the remaining surface-mounted components during the forming process at selected component eligible positions on the flat layered item where the local bending and / or stretching is reduced bending and / or stretching below a predetermined threshold, thereby including the step of designing a flat electronic circuit on the flat layered item to become a non-flat electronic circuit after the forming process.

[0029] A component eligible position is an area of the flat layered item that undergoes reduced bending and / or stretching below a predetermined threshold during the forming process. The predetermined threshold is selected to identify an area of the flat layered item where the local bending and / or stretching is limited and a reduced load is generated on the surface-mounted components disposed thereon.

[0030] A function-determined location is the position of a surface-mounted component determined by its function, typically the position of a surface-mounted component intended to inform or interact with the user, such as a tactile interface, a button, a light-emitting element, etc.

[0031] By knowing the function-determined locations on the non-flat layered item, the precursor locations on the flat layered item intended to become function-determined locations after the forming process can be determined, for example, by the above-described simulation or empirical experiments.

[0032] Surface-mounted components whose position depends on their function are placed at the defined precursor locations.

[0033] The remaining surface-mount components, whose location is independent of their function, are distributed across the remaining surface of the flat, layered item.

[0034] The remaining surface mount components are distributed so that their position is independent of their function and therefore can be placed at any position on a non-flat, layered item, where the aforementioned bending / stretching is reduced.

[0035] A component-eligible location is a location on a flat, layered item where the bending / stretching generated during the molding process to the non-flat, layered item produces local bending and / or stretching below a predetermined threshold, and is therefore a safe location for placing a surface mount component.

[0036] Once the component's eligible position is determined, the surface mount component is distributed along with the surface mount component whose position is determined by its function, in order to define the positions of all surface mount components in the electronic device.

[0037] When a surface mount component is located on a flat, layered item that is subjected to localized bending and / or stretching during the molding process, detachment may occur if the localized bending and / or stretching exceeds (or overcomes) the adhesion provided by at least one adhesive.

[0038] To prevent this detachment, this method applies to each surface mount component, For each surface mount component, determine the first load induced in the bond between the surface mount component and the flat layered item by local bending and / or stretching on the area where at least one adhesive is applied; For each surface mount component, determine a second load induced by the accumulation of local bending and / or stretching around a localized stiffening region (or stiffened region) of a flat, layered item to which at least one adhesive is applied, on the portion of the conductive track positioned around the localized stiffening region; This includes the step of defining the optimal adhesive distribution, The optimal adhesive distribution is selected to obtain a bond having a first breakage threshold (or fracture threshold) that exceeds the first load, and to generate a second load that falls below a predetermined second breakage threshold for the conductive track, with conductive tracks exceeding this threshold suffering relevant loss in electrical conductivity.

[0039] Surface mount components are primarily rigid components, and as a result, local bending and / or stretching of the flat layered item beneath the surface mount component generates a primary load (or load) on the bond between the surface mount component and the flat layered item using at least one adhesive, due to relative displacement perpendicular to the surface mount component (generating a tensile load) and / or relative displacement parallel to the surface mount component (generating a shear load). These loads can be determined by identifying the relative movement between each part of the surface mount component and the flat layered item during the molding process, taking local bending and / or stretching into account, for example by calculation, digital simulation, or empirical reproduction.

[0040] Furthermore, at least one adhesive applied to a flat, layered item creates a localized curing region of the flat, layered item, in which localized bending and / or stretching is prevented. This localized curing region results in an accumulation of localized bending and / or stretching around it, where the localized bending and / or stretching is greater than in the case where no adhesive is applied. This accumulation of localized bending and / or stretching around the localized curing region can be determined, for example, by calculation or digital simulation, or can be reproduced empirically.

[0041] If localized bending and / or stretching accumulates around a localized hardened area, and this accumulated localized bending and / or stretching induces a second load that exceeds the second fracture threshold of the conductive track, it can lead to fracture of the conductive track connected to the surface mount component.

[0042] Depending on how at least one adhesive is distributed, the bond formed between the surface mount component and the flat layered item can be made stronger, more favorably oriented, or molded to withstand the primary load. Furthermore, increasing the surface area covered by at least one adhesive through the adhesive distribution can spread or decrease the primary load over a larger surface area, reducing the differential displacement (or relative displacement) of the flat layered item between extreme regions of the adhesive-covered area due to local bending and / or stretching, thereby reducing the induced primary load.

[0043] Furthermore, the adhesive distribution affects the size and shape of the local curing region, which in turn affects the magnitude and distribution of the secondary load around it. Therefore, the optimal adhesive distribution may be selected with consideration to maintaining the generated secondary load below the secondary fracture threshold on the region containing the conductive track.

[0044] Therefore, the proposed method determines, for each surface mount component, a first load to be supported by adhesive bonding and a second load induced on the conductive track around the adhesive, and selects the optimal adhesive distribution considering such first and second loads.

[0045] The optimal adhesive distribution can be selected, for example, by iterative calculations that use different adhesive distributions to calculate the first and second loads.

[0046] The optimal adhesive distribution can be selected from, for example, the following adhesive distributions: A single droplet of adhesive in the central region beneath a surface-mount component; Multiple droplets of adhesive in the surrounding area beneath a surface-mount component; Multiple droplets of adhesive aligned (or positioned in alignment) beneath a surface-mount component; Multiple droplets of adhesive in the surrounding area around a surface mount component; The adhesive encapsulation (or casing) of surface-mount components.

[0047] To determine the first fracture threshold, known adhesive strengths per unit area and the distribution of at least one adhesive are taken into consideration, and preferably, known dimensions of the surface mount component are also taken into consideration.

[0048] The first fracture threshold can be determined for each surface-mount component.

[0049] Alternatively, the first fracture threshold can be determined for each group of surface mount components, for example, for groups of surface mount components having the same or similar (within a certain range) base surface area, width-to-length ratio, encapsulation and / or adhesion, for example, the same adhesive and the same or similar amount and / or distribution of adhesive.

[0050] For example, all surface mount components in an electronic circuit can be grouped into several groups, each group containing surface mount components having a similar base surface area and / or a similar width-to-length ratio.

[0051] For example, a group may be defined as a group comprising surface mount components having a base surface area facing a layered item that is smaller than a first value, falls between a first value and a second value greater than the first value, or is greater than the second value, and / or has a width-to-length ratio that is smaller than a first value, falls between a first value and a second value greater than the first value, or is greater than the second value.

[0052] You can define any number of thresholds and use different criteria to define groups.

[0053] These groups can also be defined as groups containing surface mount components bonded with the same adhesive. In this case, a first fracture threshold can be determined for less desirable surface mount components in each group, typically components subjected to less desirable local bending / stretching. Such a first fracture threshold is applied to all surface mount components in the same group.

[0054] The distribution of adhesive also depends on the size of the surface mount component.

[0055] Preferably, the first fracture threshold is defined as the maximum load induced by bending, stretching, and / or a combination of bending and stretching of a flat, layered item during the molding process, which is typically supportable for a given geometric shape or footprint of a component, for each specific amount and distribution of adhesive.

[0056] In some cases, some surface mount components lack a suitable component-eligible location, or the size of the suitable component-eligible location is insufficient to accommodate all the required surface mount components, in which case they become endangered surface mount components, because placing such surface mount components in other areas would likely result in their detachment during the molding process.

[0057] In other cases, even if the component is in a qualified position, the optimal adhesive distribution may not withstand the first load, preventing the occurrence of an excessive second load. According to the above, the method may include verifying whether any surface mount component is a surface mount component that is at risk, in which case, There is no optimal adhesive distribution that provides both a bond with a first breaking threshold exceeding the first load and localized bending and / or stretching accumulation around a localized cured region that induces a second load below the second breaking threshold. , and / or, the surface-mount component exposed to hazard lacks a suitable component-eligible location with reduced bending and / or stretching below a predetermined threshold.

[0058] This method, upon detection of a surface-mount component that has been exposed to hazards, includes modifying the design of the flat electronic circuit until no more surface-mount components remain exposed to hazards, by performing the following: The first corrective action is to modify the geometric shape, orientation and / or dimensions of the hazardous surface mount component to allow for a different optimal adhesive distribution, or to replace the adhesive used to attach the surface mount component with an alternative adhesive having a higher known adhesive strength per unit area, and / or A second corrective measure to reduce local bending and / or stretching by correcting the shape of non-flat layered items.

[0059] The adhesive surface area can be increased by modifying the distribution of at least one adhesive, or, without increasing the surface area, only the distribution can be modified to reduce the relative displacement between the lever and the adhesive droplets, for example, by bringing the adhesive droplets closer together. The adhesive distribution can also be changed, for example, by moving the adhesive from under the surface mount component to around it, or vice versa.

[0060] By reducing the size of the surface mount component, the surface area subjected to local bending and / or stretching of the layered item is also reduced, thus reducing the relative displacement between the lever and the opposing ends of the surface mount component, allowing it to withstand higher bending and / or stretching, and thus increasing the first fracture threshold.

[0061] Another additional first corrective measure may include replacing the adhesive with another adhesive having a higher adhesive strength per unit area, or combining two different types of adhesives with different distributions, for example, one adhesive under the surface mount component and another different adhesive around it.

[0062] Any or a combination thereof of the above first corrective measures resist the increase in the first load and thus result in an increase in the first fracture threshold, increasing the area of ​​flat, layered items in which the surface mount component can be placed without becoming a surface mount component endangered, and enabling the placement of such surface mount components in areas with local bending / stretching exceeding a predetermined threshold, typically in areas with local bending / stretching adjacent to the predetermined threshold.

[0063] If the above-described first corrective action is insufficient to address all of the hazardous surface mount components, a second corrective action may be implemented. The second corrective action includes modifying the shape of a non-flat layered item to reduce local bending and / or stretching at a location where at least one hazardous surface mount component is intended to be placed, or where a small shape modification is required to enable a safe position for the hazardous surface mount component.

[0064] Furthermore, a combination of the first and second corrective measures is also possible.

[0065] Once all surface-mount components at risk are resolved by the first or first and second corrective measures, the positions of all surface-mount components are finally determined, and the conductive tracks may then be dispersed on a flat, layered item to connect surface-mount components defining a flat electronic circuit, which becomes a non-flat electronic circuit after the molding process.

[0066] Next, a flat layered item having a flat electronic circuit thereon is manufactured according to the design obtained from the previous step of the method, and then formed through a molding process into a non-flat layered item having a non-flat electronic circuit thereon.

[0067] Non-flat layered items are designed by defining their precise volumetric shape. Typically, such a shape is defined to be complementary to the support on which such electronic device must be mounted, for example, the interior surface of a vehicle.

[0068] According to one embodiment of the present invention, the method further includes determining a second fracture threshold for each conductive track, or similarly for a group of conductive tracks, such as a broad conductive track, above which a load is induced that causes local bending and / or stretching beyond the mechanical properties of the conductive track to lead to a disruption (or interruption) of its conductivity, and the design of the flat electronic circuit further includes perfectly positioning the conductive track at a track-eligible position during the forming process such that local bending and / or stretching is below the second fracture threshold.

[0069] The second fracture threshold can be defined by calculation, using simulation, or through empirical experimentation, taking into account the acceptable curvature and / or stretch of the conductive track, which is determined by at least the manufacturing material and the thickness of the conductive track, and it determines the maximum curvature and / or stretch that can be supported by the conductive track without affecting the required conduction of electricity through it, i.e., while maintaining the conductivity of the conductive path above the threshold required to maintain the normal operation of the electronic circuit.

[0070] Typically, the second fracture threshold allows for greater bending and / or stretching than the first fracture threshold.

[0071] The method may also include, as part of the track-qualified locations, detecting track-qualified paths where the curvature and / or elongation during the molding process falls below a second fracture threshold, where the track-qualified paths are oblique to the direction of the local maximum curvature and / or elongation where the local curvature and / or elongation generated during the molding process exceeds the second fracture threshold.

[0072] According to this, the method may further include, for example, identifying track-eligible paths that can be oblique, zigzagging, or orthogonal to a local direction with the greatest local bend and / or greatest local stretch. The apparent bend and / or stretch in the direction of such a track-eligible path is less than the local bend and / or stretch in the direction with the greatest local bend and / or greatest local stretch.

[0073] Therefore, bending and / or stretching along the track-eligible path can remain below the second fracture threshold, even though the maximum local bending and / or maximum local stretching is in a region that exceeds the second fracture threshold.

[0074] If any conductive track lacks a suitable track-eligible location with local bending and / or stretching that generates an induced load (or inductive load) below the corresponding second fracture threshold, the design of the non-planar electronic circuit may be modified to increase the second fracture threshold of at least the conductive track lacking a suitable track-eligible location by modifying the width and / or thickness of the conductive track or its portion, or by modifying the constituent material of the conductive track.

[0075] The curvature and extension of non-flat layered regions are directional; therefore, their curvature and extension at each point are maximum in one direction and minimum in another, and these two directions are typically orthogonal to each other.

[0076] According to this, the region may be outside the track-eligible region because its maximum curvature and / or maximum elongation is too large, and therefore unsuitable for the track according to the embodiments disclosed above. However, in some cases, a track-eligible path can be determined on those unsuitable regions in a direction different from the direction of maximum curvature or maximum elongation, in which case the apparent curvature and apparent elongation in the direction of the track-eligible path are smaller than the maximum curvature and maximum elongation, and are below the curvature and elongation that can be supported by the conductive track considering the track break limit, i.e., if the conductive track follows one of such track-eligible paths, the conductive track can be mounted outside the track-eligible region.

[0077] A zigzag track-eligible path is a path composed of multiple consecutive segments, each segment being oblique or lateral to the maximum curvature and / or maximum stretch of the non-layered item.

[0078] According to an additional embodiment, the method may further include the steps of defining additional functional determination locations on a non-planar layered item for a printed sensor or printed actuator, such as a capacitive sensor, as part of the design of a planar electronic circuit, and identifying additional precursor locations on the planar layered item that will become additional functional determination locations after a molding process. The method then includes the step of printing the printed sensor or printed actuator on the additional precursor locations as part of the planar electronic circuit.

[0079] Print sensors or print actuators may be positioned at locations defined by their functionality. These locations are additional functional determination locations.

[0080] Optionally, the method further includes determining a third fracture threshold for each print sensor or print actuator, beyond which local bending and / or stretching would induce a load that would cause a disruption in its functionality due to exceeding the mechanical properties of the print sensor or print actuator.

[0081] If any printed sensor or printed actuator is located at one additional precursor position that is subjected to bending and / or stretching that induces a load exceeding the third fracture threshold, the design of the non-planar electronic circuit may be modified to coincide with correcting the shape of the non-planar layered item, by implementing a third corrective action to increment the corresponding third fracture threshold of the printed sensor or printed actuator, or by implementing the second corrective action described above.

[0082] Typically, the third fracture threshold allows for bending and / or stretching greater than the first fracture threshold but less than the second fracture threshold.

[0083] Third corrective measures may include modifying the width and / or thickness of the print sensor or print actuator or a part thereof, modifying the constituent material of the print sensor or print actuator, or increasing the size of the print sensor or print actuator.

[0084] Modifying the shape or size of a print sensor or print actuator, or modifying the thickness or width of its components, may result in an increase in the third fracture threshold.

[0085] According to one embodiment, the method further includes the steps of designing a structural element to be overmolded on or around a non-flat layered item, designing an overmolding process for manufacturing the structural element, and determining local flow parameters (or flow parameters) of the mold resin on the non-flat layered item during the overmolding process.

[0086] Such local flow parameters may include, for example, parameters such as the flow velocity, direction, viscosity, and temperature of the uncured fluid molding resin over each region of a non-planar layered item during the overmolding process.

[0087] A fourth fracture threshold is determined for each surface mount component, or for each group of surface mount components, for example, for a group of surface mount components (within a certain range) that have equal or similar base surface area, width-to-length ratio, encapsulation, and / or adhesion. The fourth fracture threshold is the threshold above which, if exceeded, the adhesive force provided by at least one adhesive is exceeded by the load induced by the mold resin injected according to local flow parameters during the overmolding process, and, considering the known adhesive force and distribution of at least one adhesive, as well as the known dimensions of the surface mount component, results in the detachment of the surface mount component.

[0088] Each surface mount component protrudes from the non-planar layered item and therefore obstructs the flow of the molding resin during the overmolding process. The flow of molding resin surrounding the surface mount component generates forces on such component, which may be sufficient to overcome adhesion and lead to its detachment.

[0089] Most delamination is caused by shear loads generated on the adhesive by lateral pushing forces produced by the flow of mold resin injected during the overmolding process on one side of the surface mount component. Delamination worsens as the exposed surface area of ​​the surface mount component increases and as the flow of the injected mold resin becomes faster and denser.

[0090] Surface mount components in an electronic circuit can be divided into several groups, which are surface mount components having the same or similar size and the same type of adhesive (including adhesives with the same or similar amount and / or distribution). For example, all surface mount components in an electronic circuit can be divided into several groups, each group containing surface mount components bonded with the same adhesive and with the same or similar amount and / or distribution of such adhesive.

[0091] In this case, a fourth fracture threshold may be determined for the less desirable surface mount components in each group, typically those with less desirable adhesive quantity or distribution. Such a fourth fracture threshold is applied to all surface mount components in the same group.

[0092] Next, the proposed method may include a step of verifying whether any surface-mount component is a surface-mount component at risk of being subjected to a load exceeding a fourth fracture threshold induced by local flow parameters. If an at-risk surface-mount component is detected, the design of the flat electronic circuit is modified until no more at-risk surface-mount components remain.

[0093] The fourth corrective action consists of relocating each hazardous surface mount component to a position having local flow parameters that induce a load below the fourth fracture threshold to prevent delamination during the overmolding process, and bending and / or stretching that induce a load below the first fracture threshold to prevent detachment during the molding process.

[0094] The fifth corrective action increases the corresponding fourth fracture threshold, which exceeds the load induced by local flow parameters, by modifying the geometric shape and / or dimensions of the hazarded surface mount components to reduce the load induced by local bending and / or stretching beneath them, and / or by correcting their adhesion.

[0095] Corrections to the geometric shape and / or dimensions of a surface mount component at risk can be achieved, for example, by replacing the surface mount component with an alternative surface mount component that has the same functionality but has a reduced cross-section perpendicular to the flat layered item (reducing resistance to the flow of the molded resin) and / or a larger bottom surface facing the flat layered item, where more adhesive can be applied.

[0096] By modifying the geometric shape and / or dimensions of the surface-mount component exposed to hazard, the surface subjected to local bending and / or stretching of the layered item is also reduced, thus reducing the relative displacement between the lever and the opposing ends of the surface-mount component, allowing it to withstand higher bending and / or stretching, and thus increasing the first fracture threshold.

[0097] The fifth corrective action may also include modifying the distribution of at least one adhesive to increase its bonding surface, bringing adhesive droplets closer together to reduce the relative displacement between the lever and the droplets, or modifying the position of the adhesive, for example, by moving the adhesive from under the surface mount component to around it or vice versa.

[0098] The sixth corrective action involves modifying the overmolding process to optimize local flow parameters in the area corresponding to the hazarded surface mount component, thereby reducing shear and / or temperature within that area.

[0099] The sixth corrective action may include reducing the viscosity and / or rate and / or temperature of the mold resin during the overmolding process to lower local flow parameters, and / or modifying the location and / or number of injection gates in the mold through which the molten plastic is introduced during the overmolding process.

[0100] The local flow parameters depend on the definition of the overmolding process. Such an overmolding process can be modified to correct the local flow parameters at least in some locations, for example, by modifying the position and / or number of injection gates in the mold to correct the flow direction in at least some areas, by modifying the injection speed, by modifying the plastic viscosity, or by using a different plastic composition.

[0101] Optionally, at least one surface mount component may have an anisotropic cross-section. In this case, its fourth fracture threshold may be a variable anisotropic fourth directional breakage threshold that changes depending on the directional orientation of the force applied to the surface mount component. For example, the lateral exposed surface area of ​​the surface mount component may be variable depending on its orientation, and the attachment provided by the adhesive may also be directional, for example, if the adhesive is distributed non-radially symmetrically or follows an elongated pattern.

[0102] At least some of the local flow parameters may be local flow parameters of variable anisotropic directionality depending on the directional orientation. For example, the local direction or local velocity of the mold resin are directional parameters.

[0103] The method may include a step of verifying whether any surface mount component is at risk of being subjected to a load exceeding a fourth directional fracture threshold that can be supported in at least one direction, induced by directional local flow parameters in that direction.

[0104] If a surface-mount component is found to be at risk, the design of the flat electronic circuit shall be modified until no surface-mount components remain at risk by implementing the fourth, fifth, sixth, and / or seventh corrective action, which includes correcting the orientation of the surface-mount component.

[0105] If the orientation of a surface mount component is modified, the same surface mount component with the same adhesion can withstand the same load generated thereon without any additional modification, simply by orienting the surface mount component to a better orientation optimized to increase its load resistance or reduce the induced load generated thereon.

[0106] Method steps related to desorption caused by the flow of the mold resin can be carried out independently of other features described in the present invention and, therefore, can be protected in a divisional application without such features.

[0107] Preferably, a first fracture threshold and / or a fourth fracture threshold and / or a fourth directional fracture threshold are defined individually for each surface mount component.

[0108] For at least one surface mount component, it is also proposed that the adhesive used to attach the surface mount component be a conductive adhesive interposed between the surface mount component and the conductive track, providing both adhesion and electrical connection simultaneously. This conductive adhesive can be combined with non-conductive adhesives(s) on the same surface mount component to enhance adhesion.

[0109] Optionally, the definition of an optimal adhesive distribution includes extending at least one adhesive beyond the surface mount component and covering portions of conductive tracks positioned around the surface mount component, thereby including the portions of the conductive tracks in the local curing area of ​​the flat, layered item. Each of the aforementioned extensions of the adhesive may also be an elongated extension covering an elongated region of a conductive track branching off from the surface mount component, thereby reinforcing the region of the conductive track and reducing local bending / stretching thereon.

[0110] The present invention also relates to an electronic configuration (or electronic arrangement) that can facilitate the design of non-planar layered items having non-planar circuits thereon. The configuration may include at least one communication interface for transferring data, at least one processor for processing instructions and other data, and memory for storing instructions and other data. The at least one processor is configured to generate the design step described in claim 1 or any of the dependent claims according to the stored instructions.

[0111] According to the above, at least one processor will, according to the stored instructions: Starting with the shape of a non-flat layered item, the geometric shape and dimensions of the flat layered item required to obtain the non-flat layered item through the molding process are defined by calculation, or by calculating the digital flattening (or digital flattening) of the non-flat layered item. The local bending and / or stretching experienced by a non-flat layered item during the molding process, which is necessary to convert a flat layered item to a non-flat layered item, is determined by measuring the local bending of each region of the non-flat layered item and by calculating the local stretching by comparing the surface area of ​​each region of the flat layered item with the corresponding region of the non-flat layered item. On a flat, layered item, after the molding process, several selected surface mount components must be assigned to a precursor position that is stored in memory and corresponds to a functional determination position. On a flat, layered item, during the molding process, localized bending and / or stretching is reduced to a predetermined threshold, allowing the remaining surface-mount components of the electronic circuit to be assigned to a component-eligible location. It is configured in this way.

[0112] The aforementioned definitions of the geometric shape and dimensions of a flat layered item can be obtained, for example, by digitally flattening a non-flat layered item.

[0113] The local bending of a flat layered item into a non-flat layered item can be easily determined simply by measuring the local curvature of each region of the non-flat layered item.

[0114] Furthermore, non-flat layered items are preferably items having regions with positive or negative Gaussian curvature, which cannot be produced simply by bending a flat layered item and also require stretching. The local stretching can also be mathematically characterized to transform a flat region into a curved region with positive or negative Gaussian curvature.

[0115] When circuit mounting components are assigned to flat, layered items, at least one processor is also configured to define the optimal adhesive distribution for each surface-mount component according to stored instructions: For each surface mount component, during the molding process, the relative movement between the region of the flat layered item and the region of the surface mount component bonded by at least one adhesive is calculated to determine the first load induced in the bond between the surface mount component and the flat layered item by local bending and / or stretching on the region where at least one adhesive is applied. For each surface mount component, by calculating local bending / stretching, taking into account the local curing region generated by at least one applied adhesive, a second load induced in the portion of the conductive track positioned around the local curing region of a flat, layered item to which at least one adhesive should be applied is determined by the accumulation of local bending and / or stretching around the local curing region due to curing generated in the local curing region. The optimal adhesive distribution is selected to obtain a bond with a first fracture threshold that exceeds the first load, and to generate a second load that falls below a predetermined second fracture threshold of the conductive track, above which the conductive track suffers associated losses of conductivity.

[0116] The first load can be easily calculated by at least one processor because the local bending and stretching experienced by the flat layered item in the area where the adhesive is applied are known. Therefore, the relative movement between each point of the flat layered item and each point of the surface mount component bonded to it via the adhesive can be easily determined. Knowing this relative movement allows the magnitude of the first load to be determined, and knowing the adhesive strength per unit area of ​​the adhesive, at least one processor can determine whether such a first load is above or below the first fracture threshold. Depending on the result of this calculation, modifications to the adhesive disposition may be necessary to reduce the first load, increase the surface area of ​​the adhesive, or ultimately change the adhesive to increase the adhesive strength per unit area.

[0117] These modifications can be automatically calculated by at least one processor, for example, by iteratively calculating different adhesive distributions according to stored instructions.

[0118] Next, taking into account the localized curing regions generated by the adhesive (which accumulate localized bending / stretching around the areas covered by the adhesive), at least one processor can recalculate the localized bending / stretching. Using the results of this recalculation of the localized bending / stretching accumulated around the localized curing regions, at least one processor can determine whether some of the conductive paths contained in the region surrounding the localized curing regions are subjected to a second load induced by such accumulation of localized bending / stretching, which is above (or superior to) a second fracture threshold of the conductive paths, the value of which is stored in digital memory or can be calculated by at least one processor taking into account some characteristics of the materials constituting the conductive paths stored in digital memory.

[0119] Similarly, at least one processor may also be configured to define a first corrective action or a second corrective action according to stored instructions. [Brief explanation of the drawing]

[0120] The aforementioned and other advantages and features will be better understood from the following detailed description of embodiments with reference to the attached drawings, which should be interpreted in an illustrative and non-limiting manner. [Figure 1] Figure 1 shows a perspective view of a non-planar layered item, where the three-dimensional relief is indicated by topographic lines, and two functional determination locations for two surface-mount components and one additional functional determination location for one printed sensor or printed actuator are indicated by dashed rectangles. [Figure 2]Figure 2 shows a perspective view of a flat layered item obtained by the molding process from the non-flat layered item shown in Figure 1, where two precursor positions for two surface mount components and one additional precursor position for one printed sensor or printed actuator are indicated by dashed rectangles, which correspond to the two functional determination positions and one additional functional determination position shown in Figure 1, where different regions of the flat layered item that undergo different bending and / or stretching during the molding process are indicated by dashed lines. [Figure 3] Figure 3 shows an exploded perspective view of the flat, layered item shown in Figure 2, with a flat electronic circuit on top of it. [Figure 4] Figure 4 shows a combined perspective view of a flat, layered item having the flat electronic circuit shown in Figure 3. [Figure 5] Figure 5 shows a perspective view of an electronic device including a non-planar layered item having a non-planar electronic circuit, which is obtained by a molding process from a flat layered item having a flat electronic circuit as shown in Figure 4. [Figure 6] Figure 6 shows an exploded perspective view of the electronic device shown in Figure 5, with structural elements that are overmolded on top of it; [Figures 7A-7D] Figures 7A–7D show cross-sections of a flat, layered item with a single surface-mount component attached with adhesive, illustrating four different possible optimal adhesive distributions. [Figures 8A-8D] Figures 8A–8D show cross-sections of a non-planar layered item with one surface mount component attached with adhesive, showing the same four different possible optimal adhesive distributions as in Figures 7A–7D, illustrating how localized cured areas of different sizes are generated and how this affects localized bending around the surface mount component. [Modes for carrying out the invention]

[0121] <Detailed Description of the Invention and Specific Embodiments> The proposed electronic device is shown in the figure according to a preferred embodiment, which is only a non-limiting example.

[0122] The electronic device shown in Figure 5 comprises a non-planar layered item 10 having a predetermined three-dimensional shape, on which a non-planar electronic circuit 20 is applied, and the non-planar electronic circuit comprises surface-mount components 22, conductive tracks 21, and optionally printed sensors or printed actuators 23.

[0123] Some of these surface-mount components must be located at specific predetermined function-defined positions 30 on the non-flat layered item 10. Optionally, some of the print sensors or print actuators 23 must also be located at specific predetermined additional function-defined positions 33 on the non-flat layered item 10.

[0124] The three-dimensional shape of the non-flat layered item 10, and the arrangement of the functional definition positions 30 and additional functional definition positions 33 within the three-dimensional non-flat layered item 10, are designed, for example, taking into consideration the function, arrangement, and / or aesthetic criteria of the electronic device.

[0125] According to the above, the proposed method first includes the step of determining the shape of a non-flat layered item 10, as shown in Figure 1, and the arrangement of a function determination position 30 and optionally additional function determination positions 33 thereon.

[0126] Subsequently, the shape of the flat layered item 10' obtained from the non-flat layered item 10 through the molding process is determined, for example, through a simulation of the molding process, identifying the local bending and / or stretching experienced by each region of the flat layered item 10' during the molding of the non-flat layered item 10, and identifying the arrangement of precursor positions 30' that will become functional determination positions 30 after the molding process, and the arrangement of additional precursor positions 33' that will become additional functional determination positions 33 after the molding process.

[0127] The method also includes defining a scheme for a flat electronic circuit 20' required to generate the electronic functionality of an electronic device, identifying each surface-mount component 22 by known dimensions, and the conductive tracks 21 required to obtain such electronic functionality, and optionally, a printed sensor or printed actuator 23 of this flat electronic circuit 20'.

[0128] The surface mount components 22 are classified into two groups: one group includes surface mount components 22 whose position on the non-planar layered item 10 is determined by their function, such as buttons and lights, which are intended to interact with the user; and the other group includes the remaining surface mount components 22 whose position can be freely changed.

[0129] Similarly, print sensors or print actuators can be classified into those whose position is determined by their function and the rest, but in this case, most or all of them would fall into the first group.

[0130] Furthermore, initial adhesive parameters are determined for each surface mount component 22, including the adhesive type, using known adhesive strength per unit area, to provide mounting of surface mount components onto flat layered items 10' and / or conductive tracks 21.

[0131] Then, the optimal adhesive distribution is determined for each surface mount component 22.

[0132] To obtain such an optimal adhesive distribution, the method includes determining the value of a first load induced in the bonding between each surface mount component 22 and the flat layered item 10' by local bending and / or stretching subjected to a region of the flat layered item 10' to which at least one adhesive is to be applied during the molding process.

[0133] A method for obtaining an optimal adhesive distribution also includes determining the value of a second load induced in a portion of a conductive track 21 positioned around a local curing region of a flat, layered item 10' to which at least one adhesive should be applied, by the accumulation of local bending and / or stretching around the local curing region due to curing generated in the local curing region.

[0134] Such primary loads depend on the surface area covered by the adhesive, as well as on the shape and arrangement of such surfaces, because a larger surface area distributes the load over a larger area, and also because localized bending / stretching induces greater primary loads, increasing the distance between the extreme points of flat, layered items and increasing the relative movement between them.

[0135] Therefore, the optimal adhesive distribution should cover enough surface to distribute the primary load and reduce the primary load per surface unit to less than the known adhesive strength per surface area of ​​at least one adhesive, while simultaneously minimizing the distance between the extreme ends of the region covered by at least one adhesive, for example, by concentrating the adhesive in the central region.

[0136] Preferably, the optimal adhesive distribution can be selected to minimize the distance between the extreme ends of surfaces covered by at least one adhesive in the direction that experiences most of the local bending / stretching, resulting in elongated adhesive-covered regions in directions with less local bending / stretching.

[0137] The optimal adhesive distribution also affects the secondary load that occurs on the conductive track around the surface mount component, because the adhesive creates localized curing regions of the flat, layered item with increased stiffness, where the adhesive does not experience localized bending / stretching during the molding process. Since the localized curing regions do not experience localized bending / stretching, the surrounding areas of the flat, layered item accumulate localized bending / stretching and therefore experience further localized bending / stretching.

[0138] These accumulated localized bending / stretching forces depend on the size and shape of the localized cured area, which is a result of the optimal adhesive distribution.

[0139] Therefore, the optimal adhesive distribution should be defined such that the molding process does not cause any disruption to the conductivity of the conductive track around the surface mount, taking into account that the generated second load remains below the second fracture threshold of the conductive track surrounding the localized cured area.

[0140] Similarly, a third fracture threshold can be determined for each print sensor or print actuator, or for a group of print sensors or print actuators, and the third fracture threshold is also the maximum bending and / or stretching that can be supported by the print sensor or print actuator 23 without loss of functionality.

[0141] Next, the geometric shape of the flat electronic circuit 20' is determined, and each surface-mount component 22 whose position depends on its function is placed at the corresponding precursor position 30' of the flat layered item 10', and each printed sensor or printed actuator 23 whose position depends on its function is placed at the corresponding additional precursor position 33' of the flat layered item 10', if present.

[0142] Furthermore, for each conductive track 21, or for each group of conductive tracks, a second fracture threshold is determined, for example, by empirical experimentation or simulation. The second fracture threshold is the limit beyond which the conductive track will deform due to local bending and / or stretching of the flat layered item 10' during the formation of a non-flat layered item that affects its conductivity. Such a limit can be expressed, for example, as the maximum local bending, maximum local stretching, and / or the maximum combination of local bending and local stretching that the flat layered item 10' experiences over the local area to which the conductive track 21 is applied, without affecting its conductivity, during the forming process.

[0143] The conductive tracks 21 can be classified into several groups, each group containing conductive tracks 21 of similar width. In this case, the second fracture threshold is determined for the narrower conductive tracks 21 in each group and is considered the second fracture threshold for all conductive tracks 21 in the group.

[0144] The tracks eligible region is determined on the surface of the flat layered item 10' for each conductive track, or for each group of conductive tracks having the same second fracture threshold. The tracks eligible region is the area of ​​the flat layered item 10' having local bending and / or stretching below the second fracture threshold, and can be easily determined by considering the known local bending and / or stretching and second fracture threshold of the flat layered item 10' during the molding process. The conductive tracks 21 are then distributed within the tracks eligible region according to an electric scheme to obtain the intended electronic functionality.

[0145] In some cases, connections between surface-mount components 22 require that conductive tracks 21 be defined across areas not initially defined as track-eligible regions. In these cases, track-eligible paths 34 may be determined across areas not initially defined as track-eligible regions as part of the track-eligible region.

[0146] A track-eligible path may be oblique, zigzag, or perpendicular to a local direction, for example, having the greatest local bend and / or the greatest local stretch. The apparent bend and / or stretch in the direction of such a track-eligible path is less than the local bend and / or stretch in the direction with the greatest local bend and / or the greatest local stretch.

[0147] Therefore, the bending and / or stretching along the track-eligible path 34 may be below the second fracture threshold, even though the maximum local bending and / or maximum local stretching is in a region that exceeds the second fracture threshold.

[0148] Next, several conductive tracks 21 can be mounted on the track-eligible path 34.

[0149] The electronic device may include a structural element 40 overmolded on or around a non-planar layered item 10 having a non-planar electronic circuit 20 thereon.

[0150] In this case, the method may include designing a structural element 40 to be overmolded, designing an overmolding process for manufacturing the structural element 40, defining the mold resin to be overmolded and its mold parameters, such as the viscosity of the fluid mold resin, temperature, injection speed before curing, and / or the position of the injection gate into which the fluid mold resin is introduced into the mold.

[0151] The material to be overmolded may be, for example, a thermoplastic resin, silicone rubber, or a thermosetting resin.

[0152] Next, local flow parameters of the mold resin on the non-flat layered item 10 during the overmolding process are determined. Such local flow parameters may include, for example, parameters of the mold resin on each region of the non-flat layered item during the overmolding process, such as the flow rate, direction, viscosity, temperature, or others of the mold resin before curing.

[0153] For each surface mount component 22, or for a group of surface mount components 22, the fourth fracture threshold can be determined by empirical experimentation or computer simulation. Beyond the fourth fracture threshold, the adhesive strength provided by at least one adhesive is overcome by the load induced by the local flow of the fluid molding resin, according to local flow parameters during the pre-curing overmolding process, resulting in the detachment of the surface mount component 22. The determination of the fourth fracture threshold is obtained by considering the known adhesive strength and distribution of at least one adhesive, as well as the known dimensions of the surface mount component.

[0154] If any surface-mount component 22 is a surface-mount component at risk of being subjected to an induced load exceeding the fourth fracture threshold, the design of the flat electronic circuit 20' shall be modified by implementing the fourth, fifth, or sixth corrective action until no surface-mount components remain at risk.

[0155] The fourth corrective action involves relocating each hazardous surface mount component to a position having local flow parameters that induce a load below the fourth fracture threshold to prevent detachment during the overmolding process, and having bending and / or stretching that induces a load below the first fracture threshold to prevent detachment during the molding process.

[0156] The fifth corrective action consists of reducing the size of the surface mount component and / or modifying the distribution and / or adhesive strength of at least one adhesive to increase the corresponding fourth fracture threshold that exceeds the load induced by the local flow parameters.

[0157] The fifth corrective action may also include modifying the distribution of at least one adhesive to increase its bonding surface area, bringing adhesive droplets closer together to reduce the relative displacement between the lever and the droplets, or modifying the position of the adhesive, for example, by moving the adhesive from under the surface mount component to around it or vice versa.

Claims

1. A method for manufacturing an electronic device comprising a non-planar layered item (10) having a non-planar electronic circuit (20) thereon, wherein the non-planar electronic circuit (20) comprises at least a conductive track (21) and at least one surface mount component (22) attached or attached and electrically connected via at least one adhesive having a known adhesive strength per unit area, the method is: A step of defining the geometric shape and dimensions of a flat layered item (10') suitable for being deformed into a non-flat layered item (10) through a molding process, A step of determining local bending and / or stretching on the flat layered item (10') during the molding process to the non-flat layered item (10), On the flat layered item (10'), a flat electronic circuit (20') which will become the non-flat electronic circuit (20) after the molding process is formed. Define a functional determination position (30) on the non-flat layered item (10) for some of the surface mount components (22), identify a precursor position (30') on the flat layered item (10') that will become the functional determination position (30) after the molding process, and position the surface mount component (22) on the precursor position (30'). Each of the remaining surface mount components (22) is positioned during the molding process at a selected component-eligible position (31) of the flat layered item (10') such that the local bending and / or stretching is reduced to a predetermined threshold. Therefore, the design steps and For each surface mount component (22), the optimal adhesive distribution is determined. For each surface mount component (22), determine a first load induced by local bending and / or stretching on the area where the at least one adhesive is applied to the bond between the surface mount component (22) and the flat layered item (10'). For each surface mount component (22), determine a second load induced by the accumulation of local bending and / or stretching around the local curing region resulting from the curing generated in the local curing region, on the portion of the conductive track (21) positioned around the local curing region of the flat layered item (10') to which the at least one adhesive is applied. The step defined by, The step is to select the optimal adhesive distribution such that it obtains a bond having a first breaking threshold that exceeds the first load, and generates a second load that is below a predetermined second breaking threshold of the conductive track (21) such that, if exceeded, the conductive track suffers associated loss of conductivity. A method comprising the steps of manufacturing the flat layered item (10') having the flat electronic circuit (20') thereon according to a design obtained from a preceding step of the Method, and forming the non-flat layered item (10) having the non-flat electronic circuit (20) thereon through the molding process.

2. The method according to claim 1, wherein the optimal adhesive distribution is selected from the following adhesive distributions: A single droplet of adhesive in the central region beneath the surface mount component; Multiple droplets of adhesive in the surrounding area beneath the surface mount component; Multiple droplets of adhesive aligned beneath the surface mount component; Multiple droplets of adhesive in the surrounding region around the surface mount component; The aforementioned surface mount component is embedded in an adhesive encapsulation.

3. The method according to claim 1 or 2, wherein the optimal adhesive distribution is selected by iterative calculation.

4. The method according to any one of claims 1 to 3, wherein the definition of the optimal adhesive distribution includes extending the at least one adhesive beyond the surface mount component and covering a portion of the conductive track (21) positioned around the surface mount component (22) so that the portion of the conductive track (21) is included in the local curing region of the flat layered item (10').

5. The method includes the steps of verifying whether any surface mount component (22) is a surface mount component at risk because it lacks an optimal adhesive distribution that provides both a bond having a first fracture threshold above the first load and a localized accumulation of bending and / or stretching around the localized cured region that induces a second load below the second fracture threshold, and / or verifying whether the surface mount component at risk lacks a suitable component-eligible location (31) having reduced bending and / or stretching below a predetermined threshold and load, When a surface-mount component exposed to hazard is detected, the design of the flat electronic circuit (20') is modified until no surface-mount components exposed to hazard remain. The first corrective action is to modify the geometric shape, orientation and / or dimensions of the surface mount component exposed to the hazard, thereby enabling a different optimal adhesive distribution, or to replace the adhesive used to attach the surface mount component with an alternative adhesive having a known higher adhesive strength per unit area, and / or A second corrective measure to reduce the local bending and / or stretching by modifying the shape of the non-flat layered item (10), The steps to correct this by performing the following: The method according to any one of claims 1 to 4, further comprising:

6. The manufacturing method according to any one of claims 1 to 5, further comprising the step of positioning the conductive track (21) completely in a track-qualified position (32) during the molding process such that the local bending and / or stretching induces a load below the second fracture threshold.

7. The method comprising the step of detecting a track-qualified path (34) as part of the track-qualified position (32), wherein the bending and / or stretching during the molding process along the track-qualified path (34) is below the second fracture threshold in the longitudinal direction of the track-qualified path (34), and the track-qualified path (34) is oblique to the direction of the local maximum bending and / or stretching that occurs during the molding process and exceeds the second fracture threshold, the manufacturing method according to claim 6.

8. The above method further, As part of the design of the flat electronic circuit (20'), define additional function-determining locations (33) on the non-flat layered item for a printed sensor or printed actuator (23), and identify additional precursor locations (33') on the flat layered item (10') that will become the additional function-determining locations (33) after the molding process. A manufacturing method according to any one of claims 1 to 7, comprising the step of printing the print sensor or print actuator (23) on the additional precursor position (33') as part of the flat electronic circuit (20').

9. The above method further, A step of determining a third fracture threshold for each print sensor or print actuator (23), wherein exceeding the third fracture threshold induces a third load that causes the local bending and / or stretching to cause an interruption in the functionality of the print sensor or print actuator beyond its mechanical properties. The manufacturing method according to claim 8, further comprising the step of performing a third corrective action to increase the corresponding third fracture threshold of the print sensor or print actuator (23) by modifying the shape or size of the print sensor or print actuator (23) and / or by modifying the thickness or width of at least a portion of the print sensor or print actuator (23), if any of the print sensors or print actuators (23) are positioned at one additional precursor position (33') that is subjected to bending and / or stretching that induces a third load, or by performing a second corrective action.

10. The above method further, The steps include designing a structural element (40) to be overmolded on or around the non-flat layered item (10), and designing an overmolding process for manufacturing the structural element (40). A step of determining the local flow parameters of the mold resin injected onto the non-flat layered item (10) during the overmolding process, A step of determining a fourth fracture threshold for each surface mount component (22), wherein, taking into account the known adhesive strength and distribution of the at least one adhesive and the known dimensions of the surface mount component, the adhesive strength provided by the at least one adhesive is exceeded by a load induced by the local flow of the uncured fluid mold resin according to local flow parameters during the overmolding process, resulting in the detachment of the surface mount component (22). A step of verifying whether any of the surface mount components (22) is a surface mount component that is at risk of being subjected to a load exceeding the fourth fracture threshold induced by local flow parameters, If a surface-mount component exposed to hazard is detected, the design of the flat electronic circuit (20') is modified until no surface-mount components exposed to hazard remain. A fourth corrective measure comprising correcting the position of each hazardous surface mount component to a location having local flow parameters that induce a load below the fourth fracture threshold, and / or bending and / or stretching that induces a load below the first fracture threshold, and / or A fifth corrective measure to increase the corresponding fourth fracture threshold above the load induced by the local flow parameter by modifying the geometric shape and / or dimensions of the surface mount components exposed to the hazard, thereby reducing the load induced by the local bending and / or stretching beneath them, and / or by correcting their adhesion, and / or The corrective step involves modifying the overmolding process by performing a sixth corrective action to optimize the local flow parameters in the area corresponding to the hazardous surface mount component to reduce shear and / or temperature therein, A manufacturing method according to any one of claims 1 to 9, including

11. At least one surface mount component (22) has an anisotropic cross-section, and its fourth fracture threshold is a variable anisotropic fourth directional fracture threshold depending on the orientation. At least some of the aforementioned local flow parameters are local flow parameters of anisotropic directionality that are variable depending on the directional orientation, A step of verifying whether any surface mount component is a surface mount component that is subjected to a load in at least one direction that exceeds the four-directional fracture threshold that can be supported in the same direction, induced by the local flow parameters in that direction, The manufacturing method according to claim 10, comprising the step of correcting the design of the flat electronic circuit by performing the fourth, fifth, sixth, and / or seventh corrective measures, which are present in the correction of the orientation of the surface mount components, when a surface mount component exposed to hazard is detected, until no surface mount components are left exposed to hazard.

12. The manufacturing method according to any one of claims 1 to 11, wherein the first fracture threshold and / or the fourth fracture threshold and / or the fourth directional fracture threshold are defined individually for each surface mount component.

13. If any conductive track lacks a suitable track-eligible location with local bending and / or stretching that generates an induced load below the corresponding second fracture threshold, the design of the non-planar electronic circuit is deemed to be: To change the width and / or thickness of the conductive track or its portion, The electronic device according to claim 6 or 7, wherein the material constituting the conductive track is changed to increase the second fracture threshold of conductive tracks that lack at least a suitable track qualified position.

14. The third corrective measure for increasing the third fracture threshold applies to at least one print sensor or print actuator that receives an induced load exceeding the third fracture threshold. Changing the width and / or thickness of the print sensor or print actuator or its components, By changing the constituent materials of the print sensor or print actuator, The electronic device according to claim 9, comprising increasing the size of the print sensor or print actuator.

15. The fifth corrective measure for increasing the fourth fracture threshold applies to at least one surface mount component subjected to an induced load exceeding the fourth fracture threshold, Replacing the surface mount component with an alternative surface mount component having the same functionality but with a reduced cross-section perpendicular to the flat layered item to reduce drag, and / or improving adhesion by having a larger bottom surface face the flat layered item, or This includes increasing the adhesive strength by replacing the at least one adhesive with an adhesive with a stronger adhesive strength per unit area, by modifying the distribution of the at least one adhesive, by increasing the amount of the at least one adhesive, and / or by adding a certain amount of additional different adhesives, and / or At a minimum, the sixth corrective measure for optimizing the local flow parameters on the region that induces a load on the surface mount component exceeding the fourth fracture threshold is: Lowering the viscosity and / or speed and / or temperature of the molding resin during the overmolding process to reduce local flow parameters; The electronic device according to claim 10, 11, or 12, comprising changing the position and / or number of injection gates of the mold into which the molten mold resin is introduced during the overmolding process.

16. An electronic configuration for designing a non-planar layered item having a non-planar circuit on top of it, comprising: at least one communication interface for transferring data; at least one processor for processing instructions and other data; and a memory for storing the instructions and other data, wherein the at least one processor processes the stored instructions according to the instructions. Starting from a given shape of the non-flat layered item, the geometric shape and dimensions of a flat layered item required to obtain the non-flat layered item are defined by calculation, or by calculating the digital flattening of the non-flat layered item. The local bending and / or stretching experienced by the non-flat layered item during the molding process, which is necessary to convert the flat layered item to the non-flat layered item, is determined by measuring the local bending of each region of the non-flat layered item and calculating the local stretching by comparing the surface area of ​​each region of the flat layered item with the corresponding region of the non-flat layered item. Identify precursor positions that coincide with a given predetermined position on the non-flat layered item stored in the memory, on which several selected surface mount components must be assigned. On the flat layered item, during the molding process, it is configured to identify component-eligible locations where the local bending and / or stretching is reduced to a predetermined threshold, allowing the remaining surface-mount components of the electronic circuit to be assigned. Once the circuit mounting components are assigned to the flat layered item, the at least one processor also determines the optimal adhesive distribution for each surface mounting component according to the stored instructions. For each surface mount component, the first load induced in the bond between the surface mount component and the flat layered item by the local bending and / or stretching on the area where the at least one adhesive is applied is determined by calculating the relative movement between the area of ​​the flat layered item and the area of ​​the surface mount component bonded by the at least one adhesive during the molding process. For each surface mount component, the configuration is configured to define a second load induced by the accumulation of local bending and / or stretching around the local curing region due to curing generated in the local curing region, on the portion of the conductive track positioned around the local curing region of the flat layered item to which the at least one adhesive is applied, by calculating the local bending / stretching considering the local curing region generated by the at least one applied adhesive. The optimal adhesive distribution is selected to obtain a bond having a first fracture threshold that exceeds the first load, and to generate a second load that falls below a predetermined second fracture threshold of the conductive track, such that the conductive track suffers associated conductivity loss when the second fracture threshold is exceeded, in an electronic configuration.

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