Method for producing a vehicle trim panel with electronic function

Abstract

The invention relates to a method for manufacturing a vehicle trim panel having an electronic function, comprising the following steps: providing a first sheet comprising a flexible flat plastic film having a flat first region; performing a first printing step by a two-dimensional printing process for configuring a conductive trace on the first sheet; forming the first sheet according to a three-dimensional shape so that the first area has a three-dimensional shape; performing a second printing step by fluid dispensing or transfer printing for configuring a conductive pad on the first region; attaching an electronic component to the conductive pad; injecting a plastic material on the first sheet to form a carrier sheet; and disposing a decorative cover on the carrier sheet, including a graphical sign configured to mate with the electronic component.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a vehicle trim panel with electronic functions by using In-Mold electronics (IME) technology. Background Art

[0002] In order to increase the comfort of vehicle passengers, electronic functions are often added to existing trim panels, such as decorative or functional lighting functions and / or switch functions for controlling vehicle functions such as an air conditioning system.

[0003] In some cases, both functions are provided together, so that the lighting function informs the vehicle occupants of the possibility of interacting with different switch areas hidden in the trim panel.

[0004] One of the current trends to save cost, space, weight and simplify the manufacturing methods and equipment of these functional trim panels is to provide an integral component manufactured by in-mold electronics (IME) technology.

[0005] The main concept of this technology is to integrate electronics into plastics. To this end, conductive ink is printed on a plastic film for configuring the circuits on which the electronic components are mounted. Furthermore, the plastic film can be shaped and trimmed to match the geometry of the final molded decorative part. The film is then introduced into an injection mold and then overmolded, thereby encapsulating all circuits and electronic components with the injected plastic material. The plastic material, in addition to protecting all electronic components, also serves as a structural carrier for the decorative part.

[0006] Furthermore, in order to complete the decorative panel, the structural carrier comprises a decorative covering on the opposite side with respect to the functional film.

[0007] The decorative covering forms the outer surface of the trim panel concealing the circuitry and electronic components and can simultaneously serve as an interactive surface for vehicle passengers, as all components are concealed, or as a visible surface only to display a specific decorative effect.

[0008] To this end, the decorative coverings often include pictograms, either for communication purposes, which are recognizable to the vehicle passengers, or for decorative purposes, which define specific lighting effects.

[0009] In the case where graphic symbols are used for communication purposes, they provide information about a certain function of the vehicle, for example an indication of the position of a switch area hidden by a decorative covering, or an indication of the status of a certain element of the vehicle, such as the unlocking status of an airbag.

[0010] To this end, the graphic signs may include light-transmitting portions that are backlit to make them more easily identifiable and to provide additional information by changing the color and / or intensity of the light depending on the particular circumstances, or they may include opaque portions that represent distinctive portions of the decorative covering due to a change in color, a change in relief, or both.

[0011] Where graphic signs are used for decorative purposes, they may include light-transmissive portions that are backlit to display particular decorative lighting effects.

[0012] Taking into account that the electronic components, i.e. lighting devices, sensors, etc., are arranged in a plastic film located on one side of the structural carrier forming the decorative part, and the graphic marks are arranged in the decorative covering located on the opposite side thereof, it is very important that each specific electronic component is conveniently positioned relative to the corresponding graphic mark that cooperates with it.

[0013] In the context of the present invention, the term "cooperate" means that the electronic component and the graphic sign work together for a common purpose, such as lighting purpose or switching purpose.

[0014] Problems can arise if the position of a particular electronic component relative to its mating graphic logo cannot be guaranteed.

[0015] For example, where the electronic component is a lighting device such as an LED, if it is inconveniently positioned relative to the graphic logo, undesirable hot spots may be visible through the graphic logo, or the light emitted through the graphic logo may be of insufficient intensity.

[0016] In the case where the electronic component is the inductive antenna of a proximity switch sensor, if it is not properly aligned with the graphic logo, reduced sensitivity or even malfunction of the switch function may occur.

[0017] Therefore, one of the main challenges of this technology is to ensure the accuracy of the position of each electronic component relative to the corresponding graphic mark that mates with it.

[0018] The challenges become more complex when the trim panel has a three-dimensional shape, especially when electronic components are located in specific areas of the trim component where the shape is more complex, including significant curves.

[0019] Patent EP3049227 discloses a method for manufacturing an electromechanical structure comprising a thermoformed film having a three-dimensional shape, the film comprising an electrical circuit and electronic components electrically connected to the circuit; and a plastic structural carrier overmolded on the thermoformed film by an injection molding process.

[0020] Before the film is thermoformed, the circuits are printed on the film using a 2D printing process with conductive ink.

[0021] The printed circuit comprises conductive tracks and pads at the ends of the conductive tracks to which electronic components are attached in such a way that a specific position of the electronic components is defined.

[0022] Therefore, the conductive pad is a critical area that defines a specific location of an electronic component because the location is related to the location of a corresponding graphic mark with which the specific electronic component mates.

[0023] Furthermore, the conductive pad comprises an area that is very clearly defined according to the specific characteristics of the electronic component to be mounted thereon, such as the size or power requirements of the electronic component.

[0024] This area allows ensuring the electrical connection, mechanical connection and heat dissipation of said particular electronic component in order to ensure its correct operation during its service life.

[0025] The electronic components can be attached to the film by surface mounting technology. This step includes applying attachment means on the conductive pads and subsequently assembling the corresponding electronic components by, for example, pick-and-place equipment.

[0026] In order to make the attachment step of electronic components easier, EP3049227 discloses a method in which electronic components are arranged on the film in addition to the circuit before the film is thermoformed, that is, the electronic components are attached to a flat film rather than a film with a complex three-dimensional shape.

[0027] To this end, the position where the electronic component is attached on the flat film is calculated in advance in consideration of the final shape of the three-dimensional film design, and the position is referred to as a predetermined target position.

[0028] According to EP 3 049 227, the predetermined target positions are chosen such that they omit substantial deformations in the subsequent thermoforming step which allows the film to acquire a three-dimensional shape.

[0029] On the one hand, the calculation of the predetermined target position taking into account the final three-dimensional shape of the film is a complex task involving the use of complex computer programs, and furthermore, the definition of the predetermined target position cannot be ensured without performing complementary physical tests to complement the computer programs.

[0030] On the other hand, once the electronic components are attached to the flat film, the film is subjected to two active steps, namely a thermoforming step in which the film is three-dimensionally shaped and an injection molding step in which the film is overmolded to form the structural carrier.

[0031] This means that the film containing the electronic components is exposed to thermal and mechanical stresses, which cause the film to deform and stretch so that the actual position of the electronic components at the end of the process does not match the intended target position.

[0032] On the other hand, as a result of said successive steps, the attachment means provided for connecting the electronic components to the film are also exposed to thermal and mechanical stresses, and therefore they must be strong enough to withstand the stresses to which they are subjected, so as to maintain the original attachment position, and they must be flexible enough to withstand the deformations to which they are subjected, so as not to lose their functionality. This involves the use of special attachment means with specific characteristics to withstand said conditions, which is a very expensive option.

[0033] Likewise, electronic components are exposed to the thermal and mechanical stresses generated during the hot forming step, so they must also be selected to withstand the specific conditions. Moreover, in this case, many of the most commonly used electronic components are particularly sensitive to thermal stresses.

[0034] Furthermore, the method omits locations of electronic components that are subject to significant deformation during the thermoforming step to minimize the problems disclosed above, which limits the design freedom of the final part.

[0035] To overcome the above problems, the electronic components can be attached to the film after the film has been thermoformed, ie on the film having a three-dimensional shape.

[0036] According to this scenario, since the attachment means and the electronic components are applied to the film after the thermoforming process, stress to both the attachment means and the electronic components can be avoided.

[0037] However, since the circuit is printed before the thermoforming step, the critical parts of the circuit, namely the conductive pads that define the specific location of the electronic component and have a specific geometry that ensures its correct operation, are still subject to deformation and stretching.

[0038] On the one hand, this results in a displacement of the position of the pad relative to the predetermined target position after the thermoforming step. Thus, when the pick-and-place device provides an electronic component on the corresponding pad, it will be placed outside the pad or displaced relative to its predetermined target position.

[0039] Even in this case, the pick-and-place equipment can recalculate the attachment position of the electronic component based on the actual displacement position of the electrical pad to ensure electrical connection with each other, but this recalculated position is incorrect according to the predetermined target position. Therefore, the relative position between the specific electronic component and the graphic mark matched with it is incorrect. This will cause the decorative panel to malfunction.

[0040] This problem is exacerbated when several pads are located close to each other.

[0041] On the other hand, the deformation and stretching of the film during the thermoforming step also modifies the geometry of the area defining the conductive pads. As mentioned above, said geometry is defined according to the specific characteristics of the electronic component to be mounted thereon, in order to ensure its correct operation.

[0042] Thus, the deformation of the geometric shape may affect the electrical connection, the mechanical connection and / or the heat dissipation of the electronic components, thereby causing any failure of the trim panel during its service life.

[0043] Even in some cases, where the intended target location of a conductive pad is in a very distinct position after the thermoforming process, the pad may degrade to the extent that conductivity between the conductive trace and the pad may be lost.

[0044] In view of the above-mentioned disadvantages, the object of the present invention is a method for manufacturing a vehicle decorative panel by means of in-mold electronics technology, wherein electronic components can be located in an area of ​​a film including a pronounced curved surface that is deformed when the film acquires a three-dimensional shape, and at the same time, the predetermined target position of the electronic components according to a graphic mark (with which the electronic components cooperate) set on a decorative cover and the correct operation of each electronic component are ensured to ensure the correct operation of the decorative panel. Summary of the invention

[0045] The present invention is defined and characterized by the independent claim, while the dependent claims describe additional characteristics thereof.

[0046] Firstly, since the method for manufacturing the trim panel is based on in-mold electronics technology, it allows saving costs and time by eliminating the assembly process of the different parts forming the trim panel, namely the circuit with electronic components and the structural carrier and the optional decorative covering.

[0047] Furthermore, the technology allows a reduction in weight and space due to the replacement of rigid electronic components, mainly due to the replacement of the printed circuit board with a thin and flexible plastic film comprising circuits printed with conductive ink.

[0048] In addition to the above, the present technology allows an increase in the degree of freedom in design with respect to a conventional decorative board having an electronic function including a rigid printed circuit board.

[0049] According to the method of the present invention, the printing step of the circuit is divided into two different steps, namely, a first printing step, including a two-dimensional printing process, such as screen printing, inkjet printing, flexographic printing, gravure printing or offset printing, which is used to configure the first part of the circuit on the first sheet when the first sheet includes a flat shape; and a second printing step, including a three-dimensional printing process, in particular a fluid dispensing process or a pad printing process, which is used to configure the second part of the circuit on the first sheet when the first sheet includes a three-dimensional shape.

[0050] According to the invention, the circuit is divided into two distinct parts, a first part comprising mainly conductive traces and a second part comprising conductive pads located on a pronounced curved surface of the first sheet.

[0051] The first part is the bulk of the circuit, which is mainly arranged on a flat area of ​​the first sheet after the forming process, that is, on an area that is not subjected to significant deformation and stretching during the forming process. This means that it is not complex to define and does not require high clarity and precision.

[0052] The second part includes conductive pads, located in a complex area of ​​the first sheet after the forming process. In addition, the conductive pads must be accurately defined because they define the specific location of the electronic components. The combination of the two conditions results in this part being the most complex part to define in the circuit.

[0053] Regarding the printing process, the present invention combines two different printing processes, a two-dimensional printing process and a three-dimensional printing process.

[0054] The first printing process is a two-dimensional printing process, such as screen printing. This process uses a stencil or mesh that includes holes according to a specific design to transfer ink to a flat substrate. A squeegee moves over the screen, filling the holes of the stencil or mesh with ink to imprint the design on the flat substrate.

[0055] The main feature of this process is that it is a fast printing process suitable for printing on flat substrates.

[0056] Since the majority of the circuit is printed through this two-dimensional printing process, the overall time period required to configure the entire circuit is reduced.

[0057] Since the first portion of the circuit does not require high definition and precision, the stencil or screen used during this first printing process can be simplified, thereby reducing the cost of the process.

[0058] Furthermore, since the first part does not require high definition and accuracy, the number of defective parts that do not meet the definition requirement can also be reduced.

[0059] The second printing process is a fluid dispensing process or a pad printing process.

[0060] The fluid dispensing process is a 3D printing process that uses an automatic fluid dispenser fixed on a robot or automatic device to dispense ink onto a substrate having any shape.

[0061] Pad printing is a printing process used to transfer a two-dimensional image onto a three-dimensional object. It uses a silicon pad to take a two-dimensional image from an engraved printing plate (also called a printing plate) and transfer the image to a three-dimensional substrate.

[0062] The main feature of both processes is the accurate dispensing of ink with high precision, regardless of the complexity of the shape of the substrate to be printed.

[0063] Since the conductive pads located in the complex areas of the first sheet of the circuit are printed by this three-dimensional printing process, after the forming step, the conductive pads can be accurately defined regardless of the complex shape of the first sheet, and the accurate definition is maintained after the end of the process.

[0064] On the one hand, this means that once the conductive pad has been configured, it will not be deformed by the forming process, so that its final position will not be offset relative to the predetermined target position. This contributes to the correct operation of the entire trim panel.

[0065] Furthermore, since the conductive pads are not deformed and stretched, the specific geometry of the conductive pads remains intact to meet the technical requirements of the specific electronic component to be mounted on them. This facilitates the correct operation of the specific electronic component. Furthermore, there is no need to use special conductive inks with thermoformable properties to configure the conductive pads, as they are printed after the forming process. This allows the use of common conductive inks as a cheaper option.

[0066] On the other hand, in particular the fluid dispensing process and the pad printing process itself allow to precisely dispense a controlled amount of the second conductive ink in a predetermined target area in order to define a conductive pad, regardless of the complex shape of the dispensing area.

[0067] The step of attaching the first electronic component is also performed after the forming step.

[0068] This ensures that neither the electronic component nor the attachment means connecting the electronic component to the first sheet are exposed to stresses generated during the forming process.

[0069] Therefore, the attachment means does not require special properties such as elasticity to withstand the stretching and deformation occurring during the forming process.

[0070] Furthermore, since the attachment means are not weakened during the forming process, they are better able to withstand the injection process conditions.

[0071] On the other hand, since the electronic components are not exposed to the stress generated during the forming process, the possibility of their degradation is also reduced.

[0072] Therefore, the attachment device or the electronic components do not need to have special characteristics to withstand the harsh process conditions, which allows the use of common components, resulting in a cheaper option.

[0073] Furthermore, at the end of the forming process, it may happen that the first sheet including the three-dimensional shape has any quality problem as a result of the forming process, which means that the first sheet is defective.

[0074] According to this scenario, given that the electronic component has not yet been attached to the first sheet, it does not form part of the first sheet, so the cost of the scrap material produced is cheaper than if it did form part of the first sheet.

[0075] Furthermore, dividing the printing process into two steps allows correcting possible errors generated in the first part of the circuit, which are the result of deformation and stretching of the first sheet during the forming process, which deformation and stretching may cause a loss of electrical continuity along the conductive traces. In these cases, a fluid dispensing process or a pad printing process will allow correcting said errors.

[0076] Therefore, the number of defective parts can be further reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] The description is supplemented by a set of drawings illustrating preferred embodiments, which in no way limit the invention.

[0078] Figures 1 to 16 A schematic diagram of a method for manufacturing a vehicle decorative panel having electronic functions by using components obtained in each step according to the present invention is shown. Specifically, Figure 1 , Figure 3 , Figure 5 , Figure 7 , Fig. 9 , Fig.11 , Fig.13 and Fig.15 shows a top view of the element, and Figure 2 , Figure 4 , Figure 6 , Figure 8 , Fig.10 , Fig.12 , Fig.14 and Fig.16 The corresponding cross-sectional view thereof is shown.

[0079] Fig.13 and Fig.14A top view and a cross-sectional view are respectively specifically shown according to a first embodiment of the present invention, wherein the electronic components are not vertically aligned with their corresponding graphic marks.

[0080] Fig.15 and Fig.16 A top view and a cross-sectional view according to a second embodiment of the present invention are respectively specifically shown, wherein the electronic components are vertically aligned with their corresponding graphic marks.

[0081] Fig.17 A top view of the first sheet after step d) is shown, wherein details I corresponding to the electrical pads are enclosed.

[0082] Fig.18 Shows Fig.17 Schematic enlargement of detail I.

[0083] Fig.19 A top view of the first sheet after step i) is shown, wherein light management materials influencing the light emitted by the lighting device are schematically shown.

[0084] Fig. 20 A cross-sectional view of a trim panel according to an embodiment of the present invention is shown, wherein the shape of the decorative covering matches the shape of the first sheet.

[0085] Fig.21 The first embodiment of the present invention is shown Fig. 20 Schematic enlargement of detail J shown in .

[0086] Fig. 22 The second embodiment of the present invention is shown. Fig. 20 Schematic enlargement of detail J shown in .

[0087] Fig.23 A cross-sectional view of a trim panel according to an embodiment of the present invention is shown, wherein the shape of the decorative covering partially matches the shape of the first sheet.

[0088] Fig.24 A perspective view of a decorative plate according to the present invention is shown, wherein some specific graphic marks are shown. DETAILED DESCRIPTION

[0089] Figures 1 to 16 A schematic diagram showing a method of manufacturing a vehicle trim panel 10 having an electronic function by components obtained in each step.

[0090] This method from Figure 1 and Figure 2 The process starts with step a) shown. In this step a) a first sheet material 1 is provided which comprises a flexible flat plastic film having a flat first area 1 . 1 .

[0091] The plastic film includes a material selected from the group consisting of polycarbonate (PC), polymethyl methacrylate (PMMA), polyester (PE), polyethylene terephthalate (PET), polypropylene (PP), and thermoplastic polyurethane (TPU).

[0092] The plastic film preferably comprises a thickness of 50 to 750 μm.

[0093] The method continues Figure 3 and Figure 4 Step b) is shown. In this step b), a flat first sheet 1 is printed with a first conductive ink 6 for forming conductive tracks 2.1 on its first side 1.2.

[0094] Said conductive tracks 2 . 1 printed during this step form a first part of the electrical circuit 2 .

[0095] In addition to the conductive tracks 2.1, other components forming the circuit 2 may be printed during this step b), in particular other components which remain in the substantially flat areas of the first sheet 1 after the shaping process of step c). Said optional electrical components thus also form a first part of the circuit 2.

[0096] The printing process of step b) includes two-dimensional printing processes, such as screen printing, inkjet printing, flexographic printing, gravure printing or offset printing.

[0097] The first conductive ink 6 is specially formulated in terms of material and viscosity to facilitate its compatibility with the first sheet 1 and to be applied by a two-dimensional printing process.

[0098] It may include a dispersion of particles containing a conductive metal dispersed in a solvent. The conductive metal may be, for example, silver, copper, a combination thereof, or the like.

[0099] The dynamic viscosity of the first conductive ink 6 may vary within a range of 5000 to 200000 mPas at a room temperature of 20 to 22°C.

[0100] After step b), the method continues Figure 5 and Figure 6 In step c) the first sheet 1 comprising the conductive tracks 2.1 and optionally other components forming the circuit 2 is shaped according to a three-dimensional shape so that the first area 1.1 has a Figure 6 The three-dimensional shape shown.

[0101] This means that the first region 1.1 is deformed and stretched during the forming step for obtaining the three-dimensional shape. The forming process may be performed, for example, by hot forming or cold forming.

[0102] The method then proceeds Figure 7 and Figure 8 Step d) shown. In this step d), conductive pads 2.2 configured to be connected to conductive tracks 2.1 are printed on the previously deformed first areas 1.1, in particular on the first side 1.2 of the first sheet 1, with a second conductive ink 7.

[0103] The printing process of step d) comprises a three-dimensional printing process, in particular a fluid dispensing process or a pad printing process.

[0104] In case of a fluid dispensing process, the second conductive ink 7 may be dispensed on the first sheet 1 , in particular on the first side 1 . 2 thereof, using an automatic fluid dispenser fixed to a robot or an automatic device.

[0105] Some examples of fluid dispensing techniques may be piezoelectric jet valve dispensing, aerosol jet printing, 3D dispensing or pneumatic jetting.

[0106] In the case of a pad printing process, the second conductive ink 7 may be taken from an engraved printing plate called a printing plate using a silicon pad in order to transfer said second conductive ink 7 to the first sheet 1 , in particular to its first side 1 . 2 .

[0107] The second conductive ink 7 is specially formulated in terms of material and viscosity to facilitate its compatibility with the first sheet 1 and to be applied by a three-dimensional printing process.

[0108] It may include a dispersion of particles containing a conductive metal dispersed in a solvent. The conductive metal may be, for example, silver, copper, a combination thereof, or the like.

[0109] Depending on the specific fluid dispensing technology or pad printing process, the dynamic viscosity of the second ink may vary within the range of 1 to 1,000,000 mPas at room temperature of 20 to 22°C.

[0110] For example, in the case of piezo jet valve dispensing, the dynamic viscosity is in the range of 50 to 200,000 mPas, in the case of aerosol jet printing, the dynamic viscosity is in the range of 1 to 20 mPas, in the case of 3D dispensing, the dynamic viscosity is in the range of 1 to 1,000,000 mPas, in the case of pneumatic jetting, the dynamic viscosity is in the range of 600 to 150,000 mPas, in the case of pad printing, the dynamic viscosity is in the range of 80 to 1,000 mPas.

[0111] According to certain circumstances, the first conductive ink 6 and the second conductive ink 7 are the same conductive ink. This leads to particularly advantageous results, since only a single conductive ink has to be managed during the entire process.

[0112] The conductive pad 2.2 may be directly connected to the conductive trace 2.1 to ensure electrical continuity between the two components, or it may be indirectly connected via an electrical intermediate portion 2.3, such as Fig.18 shown.

[0113] If necessary, the electrical intermediate part 2.3 is printed during step d) by fluid dispensing or pad printing.

[0114] The electrical intermediate portion 2.3 may be convenient, for example, in the case where the path of the end of the conductive trace 2.1 deviates from the originally defined path due to the first sheet 1 being stretched during the forming process, such as Fig.18 Details are shown.

[0115] In this case, the conductive pad 2 . 2 printed according to a predetermined target position, ie a position corresponding to the corresponding graphic mark 5 . 1 in the final decorative component 10 , is not connected to the conductive track 2 . 1 .

[0116] Thus, the electrical intermediate portion 2.3 is printed to connect the two components 2.1, 2.2 and in this way ensure electrical continuity between them, without requiring the position of the conductive pad 2.2 to be modified according to a predetermined target position.

[0117] Furthermore, said electrical intermediate portion 2.3 may be convenient in case several conductive pads 2.2 are very close together.

[0118] In this case, the corresponding conductive traces 2.1 are defined according to a length shorter than the length required to connect each conductive trace with the corresponding conductive pad 2.2. This is to avoid connection errors between the conductive traces 2.1 and non-corresponding conductive pads 2.2 that are very close to the corresponding conductive pads 2.2.

[0119] Thus, the electrical intermediate portion 2.3 will allow connecting said shorter conductive trace 2.1 with the respective conductive pad 2.2, thereby minimizing the risk of short circuits.

[0120] Alternatively, the invention also contemplates that said step d) may be used to print other parts of the circuit, such as partially or completely printing conductive tracks 2.1 extending over highly deformed areas of the first sheet 1, in order to ensure the integrity of said parts since they have not been subjected to the forming process of step c).

[0121] Furthermore, this step d) may be used to correct errors introduced in the first portion of the circuit 2 preconfigured in the first printing step b), which errors are a result of stretching the first sheet 1 during the forming step c).

[0122] The next step in the method involves Fig. 9 and Fig.10 Step e) is shown. In this step e), the electronic components 3 are attached to the corresponding conductive pads 2.2. Thus, the electronic components 3 can be powered by the conductive pads 2.2.

[0123] For this attachment step, for example, a pick-and-place device may be used. The pick-and-place device includes a robot for placing a surface-mount device (SMD) onto a printed circuit. The device is characterized by placing a wide variety of electronic components at high speed and high precision.

[0124] The electronic component 3 may be, for example, a lighting device such as an LED, a sensor, a resistor, a capacitor, an inductor, an antenna or a microcontroller.

[0125] Preferably, the first sheet 1 comprises a combination of several of them.

[0126] As regards the attachment means, ie the means responsible for ensuring the attachment of the electronic component 3 to the respective conductive pad 2 . 2 during the subsequent steps of the method, the invention contemplates several options.

[0127] One possible option is to attach the electronic component 3 directly to the conductive pad 2.2. In this case, the electronic component 3 is attached to the conductive pad 2.2 before the second conductive ink 7 is cured, so that the second conductive ink 7 additionally acts as an adhesive. Once cured, the attachment between the two components 2.2, 3 is reinforced.

[0128] In order to improve the mechanical connection between the two components 2.2, 3, a structural adhesive 9 may be deposited on the electronic component 3 after attaching the electronic component 3 to the conductive pad 2.2.

[0129] Fig.21 Another possible option shown in is to attach the electronic component 3 by depositing a third conductive ink 8 on the conductive pad 2.2 after it has cured. The third conductive ink 8 allows to connect the electronic component 3 electrically and mechanically to the conductive pad 2.2.

[0130] In order to improve the mechanical connection between the two elements 2 . 2 , 3 according to this option, the third conductive ink 8 can be structural.

[0131] improve Fig. 22Another option for the mechanical connection between the two components 2.2, 3 shown in is to deposit a structural adhesive 9 after the electronic component 3 has been attached to the conductive pad 2.2 by means of a third conductive ink 8. This structural adhesive 9 is deposited at least around the periphery of the electronic component 3, i.e. on its connection pins, so as not to affect the operation of the electronic component 3.

[0132] The term structural as used above to define the structural adhesive 9 and the third conductive ink 8 means that the materials comprise specific mechanical properties to withstand the mechanical and thermal stresses generated during the subsequent injection process in step f).

[0133] The third conductive ink 8 and / or the structural adhesive 9 may be applied by a fluid dispensing or pad printing process.

[0134] In the case of electronic components 3, in particular lighting devices such as LEDs, Fig.19 As shown, the method may optionally further comprise a step i) after step e), wherein step i) comprises the step of printing a light management material 11 on the lighting device, wherein the light management material affects the light emitted by the lighting device.

[0135] The light management material 11 may function as a collimator, diffuser or other optical element, depending on the specific optical properties to be achieved.

[0136] exist Fig.11 and Fig.12 In step f) shown, plastic material is injected onto the first sheet 1 , in particular onto the first side 1 . 2 thereof, in order to form the carrier sheet 4 covering the first electronic component 3 .

[0137] Optionally, if step g) is performed before step f), the plastic material is injected between the first sheet 1 and the decorative covering 5 described below.

[0138] The carrier sheet 4 may extend completely or partially over the first side 1 . 2 of the first sheet 1 and optionally over the decorative covering 5 .

[0139] The carrier sheet 4 thus comprises a second side 4.2 facing the first side 1.2 of the first sheet 1 and a first side 4.1 opposite to the second side 4.2.

[0140] The main function of the carrier sheet 4 is to provide structural support for the decorative panel 10 .

[0141] The plastic material forming the carrier sheet 4 may be, for example, a thermoplastic such as polycarbonate (PC), polymethyl methacrylate (PMMA), polypropylene (PP) or polyamide (PA), polyethylene terephthalate (PET), or a thermosetting plastic such as polyurethane (PU).

[0142] In this step f), a first sheet 1 having a three-dimensional shape and comprising circuit 2 and electronic components 3 is introduced into an injection mold and plastic material is then injected onto said first sheet 1 , at least partially embedding both circuit 2 and electronic components 3 .

[0143] According to an embodiment of the invention, where the electronic component 3 is in particular a lighting device such as an LED, the plastic material may be a light-transmitting material which may be transparent or translucent. In the case of translucent, it may include light-diffusing additives.

[0144] The carrier sheet 4 can be formed entirely or partially of a light-transmitting material. In the case of partial formation, the light-transmitting material extends only at one or more portions of the carrier sheet 4 that are affected by the light emitted by the lighting device. In the last case, the carrier sheet 4 comprises both light-transmitting and opaque materials.

[0145] Thus, the carrier pane 4 or a portion of the carrier pane 4 acts as a light guide for distributing and transmitting light emitted by the lighting device towards the first side 4 . 1 .

[0146] Finally, the method includes the following steps: Fig.13 and Fig.14 and according to the second choice Fig.15 and Fig.16 Step g) is shown. In this step g), a decorative covering 5 is provided. The decorative covering 5 is arranged on the first side 4 . 1 of the carrier sheet 4 .

[0147] The decorative covering 5 thus comprises a second side 5 . 3 facing the first side 4 . 1 of the carrier sheet 4 and a first side 5 . 2 opposite the second side 5 . 3 , which first side constitutes the visible side of the decorative panel 10 .

[0148] The decorative covering 5 may comprise as the first sheet material 1 a plastic film, a wood veneer sheet, a leather sheet, a textile, a metal sheet, a stone sheet, a cork sheet or any other sheet material commonly used as a decorative covering in vehicles.

[0149] In the particular case that the decorative covering 5 is a plastic film as the first sheet material 1 , the decorative covering 5 can be manufactured according to steps a) to e) or according to steps a) to c).

[0150] Thus, the decorative covering 5 may be shaped according to a three-dimensional shape and may comprise the electrical circuit 2 in addition to the electronic components 3 .

[0151] In case the decorative covering 5 is formed according to a three-dimensional shape, the shape may be as follows Fig. 20 The shape of the first sheet 1 is exactly matched as shown, or it can be Fig.23The shape shown partially matches that of the first sheet 1 .

[0152] The present invention also contemplates an option in which the shape of the decorative covering 5 does not match the shape of the first sheet 1, such as Fig.14 and Fig.16 shown.

[0153] According to one embodiment of the invention, the decorative cover 5 may be inserted as the first sheet 1 into the injection mold to inject plastic material therebetween for forming the decorative component 10 , that is, step g) is performed before the injection molding step f).

[0154] According to another embodiment of the invention, after the injection moulding step f), the decorative covering 5 may be attached to the assembly formed by the first sheet 1 and the carrier sheet 5 , ie outside the injection mould, for example by a lamination process.

[0155] The decorative covering 5 may also comprise a coating applied directly on the carrier sheet 4 .

[0156] The decorative cover 5 may also include a laminated material. For example, it may include a light-transmitting layer with a decorative effect, a masking layer disposed on one side of the light-transmitting layer, and a protective layer or coating disposed on the other side of the light-transmitting layer (particularly on the visible side of the decorative board 10).

[0157] Preferably, the decorative covering 5 is partially opaque so as to hide all elements inside the trim panel 10 .

[0158] The decorative covering 5 has at least one graphic symbol 5 . 1 which is configured to cooperate with the electronic component 3 of the first sheet 1 .

[0159] As mentioned above, in the context of the present invention, the term "cooperation" means that the electronic component 3 and the corresponding graphic symbol 5.1 work together for a common purpose.

[0160] In the case where the electronic component 3 is a lighting device, the light emitted by the lighting device is transmitted to the outside of the decorative plate 10 through the corresponding graphic logo 5 . 1 , so the common purpose is to emit light to the outside of the decorative plate 10 .

[0161] In the case where the electronic component 3 is an inductive antenna for a proximity switch, a signal induced by the inductive antenna is detected by the graphic symbol 5.1, for example due to a vehicle passenger's finger approaching or touching the graphic symbol 5.1. The common purpose is to activate the proximity switch.

[0162] Graphic signs 5.1 may be any graphic or symbolic image that is recognizable to vehicle passengers and is used for communication purposes and / or decorative purposes, such as Fig.24 shown.

[0163] The graphic logo 5.1 may be a light-transmitting part that is backlit in order to make it easier to recognize and provide additional information by changing the color and / or intensity of the light according to the specific environment.

[0164] The graphic mark 5.1 may also be an opaque portion which represents a distinctive portion of the decorative covering 5 due to a change in color, a change in relief or both.

[0165] The graphic mark 5.1 can be arranged by printing on the cover layer 5 or on any layer forming the cover layer 5. It can also be arranged by laser cutting an opaque layer as a mask.

[0166] exist Fig.13 and Fig.14 In the embodiment shown, the electronic component 3 comprises a lighting device, such as an LED, and the corresponding graphic mark 5.1 matched with the lighting device is light-transmissive.

[0167] like Fig.13 As shown, the lighting device is conveniently positioned according to a position that is not aligned with the corresponding graphic mark 5 . 1 relative to a main axis of the lighting device extending perpendicularly through the thickness of the decorative panel 10 .

[0168] The misaligned positions are specifically chosen to fulfil a dual function, to avoid undesired hot spots due to the lighting device being too close to the respective graphic sign 5.1, and to ensure that the light provided through the respective graphic sign 5.1 meets the requirements in terms of light intensity.

[0169] exist Fig.15 and Fig.16 In the embodiment shown, the electronic component 3 comprises an inductive antenna for a proximity switch. The corresponding graphic mark 5.1 cooperating with the inductive antenna can be light-transmissive or an opaque part that can be distinguished by the vehicle user.

[0170] like Fig.15 As shown, the sensing antenna is conveniently positioned relative to a main axis of the sensing antenna extending perpendicularly through the thickness of the trim panel 10 according to the alignment with the corresponding graphic mark 5.1, so as not to impair the sensitivity of the antenna.

[0171] The present invention also considers other embodiments, in which a specific graphic mark 5.1 cooperates with two electronic components 3, such as an induction antenna and a lighting device. This situation makes it easier to identify the graphic mark 5.1 used to switch a certain function because the graphic mark is backlit.

[0172] Furthermore, the present invention also contemplates other embodiments in which a particular graphic sign 5.1 is simultaneously coupled to more than one lighting device. This may be convenient depending on the intensity requirements or size of the graphic sign 5.1 to be backlit.

[0173] The trim panel 10 of the present invention may be any trim panel that has an aesthetic function and covers any interior or exterior body portion of a vehicle.

[0174] Where the trim panel 10 covers an interior body component of a vehicle, it may be, for example, a door trim, a pillar trim, an instrument panel trim, a center console trim, a carpet, a roof trim, a sun visor, or a portion of any of these. Other interior trim panels are contemplated by the present invention.

[0175] Where the trim panel 10 covers an exterior body component of a vehicle, it may be, for example, a door exterior trim, a pillar exterior trim, an exterior logo trim, a radiator grille trim, or a portion of any of these. Other exterior trim panels are contemplated by the present invention.

Claims

1. A method for manufacturing a vehicle decorative panel (10) having electronic functions, comprising the following steps: a) providing a first sheet material (1), said first sheet material comprising a flexible flat plastic film having a flat first area (1.1), b) printing conductive traces (2.1) on said first sheet (1) with a first conductive material (6) by screen printing, inkjet printing, flexographic printing, gravure printing or offset printing, c) shaping the first sheet (1) including the conductive traces (2.1) according to a three-dimensional shape, so that the first area (1.1) has a three-dimensional shape, d) printing a conductive pad (2.2) connected to the conductive trace (2.1) on the first area (1.1) with a second conductive ink (7) by fluid dispensing or pad printing, e) attaching an electronic component (3) to the conductive pad (2.2) so that the electronic component (3) can be powered via the conductive pad (2.2), f) injecting plastic material onto the first sheet (1) to form a carrier sheet (4) covering the electronic component (3), wherein the carrier sheet (4) comprises a second side (4.2) facing the first sheet (1) and a first side (4.1) opposite to the second side (4.2), g) providing a decorative covering (5), the decorative covering (5) being arranged to be located on the first side (4.1) of the carrier sheet (4), comprising a graphic mark (5.1) arranged to cooperate with the electronic component (3).

2. The method for manufacturing a vehicle decorative panel (10) having electronic functions according to claim 1, wherein: In step d), an intermediate portion (2.3) is also printed with the second conductive ink (7) by fluid dispensing or pad printing, the intermediate portion (2.3) connecting the conductive trace (2.1) and the conductive pad (2.2).

3. The method for manufacturing a vehicle decorative panel (10) having electronic functions according to claim 1, wherein: The decorative covering (5) comprises a plastic film produced according to steps a) to e).

4. The method for manufacturing a vehicle decorative panel (10) having electronic functions according to claim 1, wherein: The electronic component (3) is directly attached to the conductive pad (2.2).

5. The method for manufacturing a vehicle decorative panel (10) having electronic functions according to claim 1, wherein: The step e) further comprises printing a third conductive ink (8) on the conductive pad (2.2), wherein the third conductive ink is configured to attach the electronic component (3) to the conductive pad (2.2).

6. The method for manufacturing a vehicle decorative panel (10) having electronic functions according to claim 5, wherein: The third conductive ink (8) is structural.

7. The method for manufacturing a vehicle decorative panel (10) having electronic functions according to any one of claims 1 or 5, wherein: After step e), a structural adhesive (9) is dispensed onto the electronic component (3).

8. The method for manufacturing a vehicle decorative panel (10) having electronic functions according to claim 1, wherein: The electronic component (3) is a lighting device.

9. The method for manufacturing a vehicle decorative panel (10) having electronic functions according to claim 8, wherein: The plastic material is light-transmissive, and the carrier sheet (4) is a light guide configured to distribute and transmit light emitted by the lighting device toward the first side (4.1) of the carrier sheet (4).

10. The method for manufacturing a vehicle decorative panel (10) having electronic functions according to claim 9, wherein: The light transmitted by the light guide passes through the graphic logo (5.1) so as to be visible outside the decorative panel (10).

11. The method for manufacturing a vehicle decorative panel (10) having electronic functions according to claim 10, wherein: The lighting device is positioned relative to a main axis of the lighting device extending perpendicularly through the thickness of the decorative panel (10) according to a position that is not aligned with the corresponding graphic mark (5.1).

12. The method for manufacturing a vehicle decorative panel (10) having electronic functions according to claim 1, wherein: The electronic component is an antenna for a proximity switch, the antenna being positioned relative to a main axis of the antenna extending perpendicularly through the thickness of the decorative panel (10) according to a position aligned with the corresponding graphic mark (5.1).

13. The method for manufacturing a vehicle decorative panel (10) having electronic functions according to claim 8, wherein: The method further comprises, after step e), a step i) comprising the step of printing a light management material on the lighting device, the light management material affecting the light emitted by the lighting device.

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