Functional and / or decorative part comprising a pattern visible by backlighting and its manufacturing process

Abstract

Functional and / or decorative part comprising a pattern visible by backlighting and method of manufacturing same The invention relates to a functional and / or decorative part (1), interior or exterior, for a vehicle, with a luminous pattern (2), only or particularly visible by backlighting, this part (1) comprising a transparent and self-supporting substrate layer (3), with opposite front (4) and rear (4') faces and comprising, on its rear face (4'), at least locally, a discontinuous layer (5) forming a decorative and / or informative pattern, resulting from an inkjet deposition of an optically opaque substance (5') and intended to be selectively exposed to lighting (6),said part (1) further comprising at least one transparent or translucent surface layer (7) covering the front face (4) of the substrate layer (3) and / or a white colored layer partially or totally covering the rear face (4') of the substrate layer (3) bearing the pattern (5) Figure to be published with the abstract: Fig. 2,

Description

Title of the invention: Functional and / or decorative part comprising a pattern visible by backlighting and its manufacturing method

[0001] The present invention relates to the field of vehicle parts, components and elements, and in particular interior or exterior trim, lining or structural parts for vehicles, allowing the production of at least one light pattern only visible by backlighting, also called a "secret till lit effect".

[0002] In this context, the invention relates to such a functional and / or decorative part of this type, a vehicle equipped with at least one such part and a method of manufacturing such a part.

[0003] The present invention falls in particular, but not limited to, the current trend aimed, in the context of the interior and / or exterior equipment of vehicles, at producing certain parts or pieces with cutouts or thinning or at covering certain areas with added patterns, in such a way that they allow light effects to be produced at the level of their apparent surface by backlighting, that is to say by lighting from the rear through a complex formed by a stack of layers forming said part or covering said area.

[0004] These light effects are intended in particular to make particular decorative patterns, messages, logos and / or pictograms appear, to create light halos, to produce diffuse lighting or even to cause the appearance of certain tactile or inductive controls to be activated by the user: these varied light effects being visible only when the light source(s) located at the rear is / are activated and emits. Alternatively, these light effects may, where appropriate, also be apparent, possibly in a reduced or partial manner, in the absence of any lighting, and for example become particularly visible, and therefore strongly attract the attention of the driver or an occupant, when an associated backlight is activated.

[0005] This concept appeals to users and is attractive because it allows large surfaces to be presented inside vehicles without buttons and controls. It also allows, inside or outside the vehicle, to cause surprise effects when the light effect appears, in particular when it takes place in a neutral and judiciously chosen location, not suggesting such an effect, such as for example a grille, a rearview mirror shell, the lid of a glove box, the back of a headrest, a center console, a door panel, a dashboard or a similar part or part of interior equipment.

[0006] Many achievements around this concept are already known.

[0007] Thus, a first type of solutions, for example known from documents FR 3 118 726 (in the name of the applicant), FR 3 096 301, US 7 097 913, US2016 / 0121592, US2015 / 0343837 and GB 2 541 893, implement backlighting through several layers of more or less transparent or translucent materials, in particular through orifices or arranged thinnings, which cause diffraction effects of the light radiation, and interference or blurring at the edges or limits. The visual effects generated are therefore generally relatively tenuous, with imprecise and blurred edges, which result in a delimitation of the displayed image which lacks sharpness and in a strong limitation of the display resolution. Thus, they generally do not allow the display of signs, pictograms or texts that are easily recognizable or readable.In addition to their relatively complex production, these multi-layer materials include natural materials, which makes their application outdoors difficult, and they do not allow any customization of the rendering.

[0008] Embodiments allowing sharper displays are known for example from documents EP 4147867 and EP 4147868 in the name of the applicant, but they also have at least some of the other limitations mentioned above.

[0009] Finally, all these solutions implement one or more masks when the patterns are created by applying a layer of paint or the like, which makes their creation tedious.

[0010] Other embodiments are also known in which the rear face of a transparent substrate is covered either entirely with a layer of opaque ink in which a pattern is engraved by removing material (for example by a laser), or with several layers of inks of different types (opaque, semi-transparent) forming by cooperation a light pattern during illumination. These methods are long, tedious and complex and require large quantities of inks, possibly of different types. They are also relatively unadaptable and do not guarantee with certainty the desired effect with the desired quality.

[0011] Finally, there is also a demand for the integration into the aforementioned parts, in a manner that is both discreet and easily accessible and identifiable, of technical functionalities of various natures, for purposes of comfort, control, monitoring, security or other.

[0012] The present invention aims to overcome at least the main limitations mentioned above of existing solutions, and possibly also to satisfy other demands.

[0013] For this purpose, it relates to a functional and / or decorative part, interior or exterior, for a vehicle, with a luminous pattern, only or particularly visible by backlighting, this part comprising a transparent and self-supporting substrate layer, with opposite front and rear faces and comprising, on its rear face, at least locally, a discontinuous layer forming a decorative and / or informative pattern, resulting from an inkjet deposition of an optically opaque substance and intended to be selectively exposed to lighting, said part further comprising at least one transparent or translucent surface layer covering the front face of the substrate layer and / or a layer with occulting properties, preferably white in color, partially or totally covering the rear face of the substrate layer bearing the pattern.

[0014] The invention will be better understood from the following description, which relates to preferred embodiments, given as non-limiting examples, and explained with reference to the appended schematic drawings, in which:

[0015] [Fig-1] is a schematic sectional view of an interior arrangement or component or vehicle exterior incorporating a functional and / or decorative part with a light pattern only visible by backlighting, according to a first embodiment of the invention;

[0016] [Fig.2], [Fig.3], [Fig.4] and [Fig.5] are schematic sectional views, the case possibly partial, of four other embodiments of a functional and / or decorative part according to the invention.

[0017] As shown in Figures 1 to 5, the invention relates to a functional and / or decorative part (1), interior or exterior, for a vehicle, with a luminous pattern (2), only or particularly visible by backlighting, this part (1) comprising a transparent and self-supporting substrate layer (3), with opposite front (4) and rear (4') faces and comprising, on its rear face (4'), at least locally, a discontinuous layer (5) forming a decorative and / or informative pattern, resulting from an inkjet deposition of an optically opaque substance (5') and intended to be selectively exposed to lighting (6), said part (1) further comprising at least one transparent or translucent surface layer (7) covering the front face (4) of the substrate layer (3) and / or a layer (8) with occulting properties, preferably white in color,partially or completely covering the rear face (4') of the substrate layer (3) bearing the pattern (5).

[0018] Thanks to these arrangements, the part (1) with its luminous pattern (2) is not only simple to manufacture (direct deposition on a transparent substrate and without the use of a mask), and by using only the quantity of substance (5') necessary to produce the pattern in a layer (economical manufacturing), it also presents a definition and a quality of effects superior to existing solutions, with the possibility of having very diverse pattern shapes and to easily vary said shape and the degree of opacity of the pattern.

[0019] As indicated above, and depending on the nature and the production of the discontinuous layer (5) and the layer (8) with occulting properties, the light pattern (2) appearing on the front or visible face (4) of the substrate layer (3) can, in the absence of backlighting, either be totally invisible (production with a “secret until illuminated” effect), or be at least discernible or weakly visible, that is to say in a tenuous manner or without notable highlighting, as an attenuated projection of the pattern provided by the discontinuous layer (5). The part can thus, for example, have a surface with a homogeneous and uniform color, matt or glossy, in the absence of backlighting; when the backlighting is activated, the light passes through the different layers of the part (1) and reveals a pattern, colored or not, with a distinct color compared to the background, the whole forming the light effect (2).

[0020] The transparent or translucent surface layer(s) (7) cover at least the part of the front face (4) of the substrate layer (3) which is visible when the part (1) is installed in the vehicle. The layer (8) with occulting properties covering the rear face (4') may be present only in the areas of said rear face (4') not covered by the opaque discontinuous layer (5) forming the decorative and / or informative pattern, therefore the bare areas of this rear face (4'). But preferably, and in particular for reasons of ease of application, said layer (8) covers the entirety of this rear face (4'), including the discontinuous layer (5).

[0021] Optically speaking, the light pattern (2), which appears when the backlight (6) is activated, can be produced positively or negatively by the pattern (5). In other words, this light pattern (2) can either be formed by the light passing through the opaque discontinuous layer (5), or correspond to the (dark) pattern delimited by the light passing through the opaque discontinuous layer (5).

[0022] The layer (8) with occulting properties, preferably white in color, advantageously contributes to defining the degree of opacity of the pattern (when it covers the latter). By occulting properties in relation to the layer (8), it is meant herein that the latter contributes, on the one hand, to the total erasure or not of the visibility of said pattern at the surface (4) in the absence of backlighting, but also, and even mainly, to the suppression of the visibility of the elements and components located at the rear of the part (1) and which could be visible at the level of the visible face of the part due to the transparency of the substrate layer (3). In any event, this layer (8) allows the light coming from the backlighting means (6) to pass through, at least partially, to highlight the pattern (5) and generate a light pattern (2) sufficiently visible on the front face (4). By varying the opacity of this layer (8), for example by varying its thickness or the nature of the substance which constitutes it, the rate of passage of light through it is directly varied. It is applied last, so that the pattern (5) is perfectly visible and not altered on the front face (4), while said layer (8) is invisible at this level and obscures the environment which is located beyond it at the rear of the part (1).

[0023] Preferably, this layer (8) is white in color, but it can also have a different color, in particular black.

[0024] In addition to allowing the production of a light pattern (2) by backlighting due to its at least relative opacity, it may be provided that the opaque substance (5'), for example a UV crosslinking ink, has electrical conductivity properties, at least part of the decorative and / or informative pattern formed by the discontinuous layer (5) also constituting a functional component of the electromagnetic, electrical or electronic type.

[0025] The pattern (5) thus fulfills a second technical function, linked or not to its function of participating in the generation of a light effect. Indeed, the light effect can provide an indication of the additional optional technical function, or else be completely dissociated from the latter.

[0026] According to a first possible variant, the functional component formed by at least part of the decorative and / informative pattern consists of an antenna for the reception, emission and / or transmission of an electromagnetic signal.

[0027] According to a first possible variant, the functional component formed by at least part of the decorative and / informative pattern consists of a proximity or contact detector, for example of the inductive, capacitive, mechano-electric or piezoelectric type.

[0028] According to a preferred embodiment, the discontinuous layer forming the decorative and / or informative pattern (5) is made up of successive deposits, by projection in superimposed layers of droplets of the opaque substance (5') forming ink, made according to patterns of successive elementary deposits, offset from each other and forming by accumulation said pattern (5), the surface of this pattern (5) being optically opaque or having translucency properties, where appropriate at least on one zone or region (of this surface).

[0029] The conductive pattern (5) is well connected to the electronic device which delivers or receives its electrical signal, and the type of which depends on the function(s) performed. Optionally, different parts of the pattern (5) can perform different functions.

[0030] Advantageously, the opaque discontinuous layer (5) is applied directly to the rear face (4'). However, depending on the materials constituting the substrate layer (3) and the substance (5'), and / or to possibly guarantee improved bonding of the discontinuous layer (5), it may be provided that the substrate layer (3) comprises on its rear face (4') a layer (9) of primer or bonding agent, at least translucent, preferably transparent, on which is deposited the discontinuous layer forming the decorative and / or informative pattern (5).

[0031] In accordance with a first variant embodiment, the transparent or translucent surface layer (7), covering the front face (4) of the substrate layer (3) and constituting the visible surface of the part (1), consists of a layer of protective varnish or lacquer.

[0032] In accordance with a second embodiment variant, the transparent or translucent surface layer (7), covering the front face (4) of the substrate layer (3) and constituting the visible surface of the part (1), consists of an added layer, such as for example a film, a skin, a complex layer formed of a textile or a skin associated with an underlying comfort layer, foam or cellular material, or even a plastic-coated fabric, this added surface layer being either overmolded onto said front face (4), or prefabricated and secured to said front face (4) by means of an adhesive layer (10), transparent or translucent, for example a layer of glue or a double-sided adhesive strip, of optical quality.

[0033] Advantageously, the substrate layer (3) consists of a transparent plastic material, for example chosen from polycarbonate, polypropylene and polymethyl methacrylate.

[0034] Advantageously, the layer (8) with occulting properties, for example white in color, substantially opaque and covering either the entire rear face (4'), or at least the areas of the rear face (4') not comprising the discontinuous layer forming the decorative and / or informative pattern (5) or even only the pattern (5), consists of a film, a layer of varnish, a layer of paint or a layer of ink, having where appropriate a constitution and a nature similar to those of the substance (5') forming said pattern (5).

[0035] As examples, the aforementioned layers can be chosen as follows, when present:

[0036] - Layer (7): layer visible to users. It can be of different compositions: textile covering, translucent material such as plastic coated fabric (Tep), PVC, PU, ​​or any other translucent decorative covering.

[0037] - Layer (8): layer (8) is the layer, white in color for example, but not necessarily, allowing the function of occultation and partial opacity. It can be formed by: application of a white tint film or white paint (in PU for example), depositing a layer of white ink or white varnish. As indicated previously, this layer (8) can also have another color, for example black.

[0038] - Layer (9): bonding layer of the bonding primer or varnish type hanging.

[0039] In accordance with a possible concrete embodiment of the part (1), and for the case where they are present, the different superimposed and constituent layers of said part (1) with a stratified structure respectively have the following thicknesses: substrate layer (3): thickness between 2 mm and 5 mm, discontinuous layer of substance (5') forming the pattern (5): thickness between 10 pm and 500 pm, surface layer (7): thickness between 0.5 mm and 2 mm and layer (8) of white color: thickness between 10 pm and 1 mm.

[0040] Comparing Figures 1 to 5, it can be seen that the substrate and discontinuous layers (3, 5) are always present, while the rear occulting layer (8) and the surface transparent / translucent layer (7) can each be present individually (one or the other) or together, or not at all.

[0041] In relation to a preferred application of the invention, the functional and / or decorative part (1) constitutes with at least one lighting means (6) an arrangement or a structural component (11), intended to be mounted externally on or internally in a vehicle, where appropriate as a removable and interchangeable modular part.

[0042] The invention also relates to a motor vehicle comprising at least one functional and / or decorative part (1) as described above, as an interior or exterior part, said vehicle also comprising at least one lighting means (6) for producing, selectively and by backlighting, a light pattern (2) on the visible face of said part (1), said part (1) and said lighting means (6) together forming a structural arrangement or component (11), possibly also integrating a technical function of an electromagnetic, electrical or electronic nature and constituting, where appropriate, a removable and interchangeable modular part of said vehicle.

[0043] Finally, the invention also relates to a method for manufacturing a functional and / or decorative part (1), for interior or exterior mounting on a vehicle and having a light pattern (2) only visible by backlighting, for example a part (1) as described above, said method comprising at least the following steps consisting of: - providing a transparent and self-supporting substrate layer (3), with opposite front (4) and rear (4') faces, shaped or molded to constitute the body of the part (D, - depositing on the rear face (4') of this substrate layer (3), at least locally, a discontinuous layer (5) forming a decorative and / or informative pattern using an inkjet deposition process of an opaque substance (5'), for example an ink with UV crosslinking, this deposit being controlled by a calculation and control means in accordance with a predetermined program, - applying or adding at least one transparent or translucent surface layer (7) so as to cover the front face (4) of the substrate layer (3) and / or a layer (8) with occulting properties, preferably white in color, so as to cover either the entire rear face (4'), or at least the areas of the rear face (4') not comprising the discontinuous layer forming the decorative and / or informative pattern (5), or only said pattern (5).

[0044] Advantageously, the method consists, in order to produce the discontinuous layer (5) forming the decorative and / or informative pattern, in projecting onto the rear face (4') of this substrate layer (3), by successive deposition phases and in superimposed layers, ink droplets (5') distributed surfacewise according to elementary droplet distribution patterns, predetermined and specific to each deposition phase, the successive depositions being carried out with mutual offsets between the patterns respectively applied and the successively projected droplets forming, by cumulative aggregation and crosslinking on the rear face (4'), said pattern (5).

[0045] More precisely, the method may consist, depending on the shape of the pattern (5) sought, in defining for the successive deposition phases elementary droplet distribution patterns with alignments in two perpendicular directions, possibly producing a staggered distribution of the droplets of a pattern, and in shifting the elementary distribution patterns of two consecutive deposition phases by a step corresponding to a fraction of the distance between two droplets, for example to half of this distance.

[0046] Most preferably, the method for forming the discontinuous layer (5) forming a pattern may correspond to the method described in document WO2016142510, and possibly documents WO2019219273 and WO2019243440, of the applicant.

[0047] In terms of possibilities for adapting and adjusting the light effect (2), the method may provide for being able to adjust the size of the droplets or the number of successive deposition phases to form the discontinuous layer (5) as a function of the optical properties desired for the pattern that it forms, between opacity and relative translucency, and taking into account the optical opacity properties of the substance (5') constituting the projected ink.

[0048] In order to facilitate the implementation of the method, the latter may provide that the layer (8) with occulting properties, preferably white in color, is applied by projection onto the rear face (4'), covering it completely or not, namely covering or not the decorative and / or informative pattern (5), and putting in uses an inkjet deposition process similar to that used for producing said pattern (5).

[0049] In order to be able to guarantee a secure attachment of the pattern (5) on the rear face (4'), whatever the nature of the substance (5') and of the substrate layer (3), the method may consist in applying to the rear face (4') of the substrate layer (3) a layer (9) of primer or attachment, at least translucent, preferably transparent, before the deposition of the discontinuous layer (5) forming the decorative and / or informative pattern on this face (4').

[0050] Furthermore, it may be provided to deposit a layer of protective varnish or transparent or translucent lacquer on the front face (4) of the substrate layer (3) to form the visible surface layer (7) of the part (1).

[0051] Alternatively, the method may consist of providing and adding as a transparent or translucent surface layer (7), intended to cover the front face (4) of the substrate layer (3) and to constitute the visible surface of the part (1), a film, a skin, a complex layer formed of a textile or a skin associated with an underlying comfort layer, foam or cellular material, or even a plastic-coated fabric, this added surface layer being either overmolded onto said front face (4), or added as a prefabricated layer and secured to said front face (4) by means of an adhesive layer (10), transparent or translucent, for example a layer of glue or a double-sided adhesive strip, of optical quality.

[0052] As a concrete implementation of a method in accordance with the invention, said method may consist, at least for the deposition of the discontinuous layer (5) forming the decorative and / or informative pattern, and possibly also for the deposition of the rear layer (8) and / or for the deposition of the surface layer (7), in moving the substrate layer (3), for example with a six-axis robotic arm, in front of a multi-head jet projection device, the projection of the substance intended to form the layer in question (5, 7, 8) being controlled by a calculation and control means regulating the wave train and the projection speed of the drops in accordance with a predetermined program and as a function of the geometry of the substrate layer (3) and its position and its speed of movement relative to said projection device,the substance (5') at least of the drops forming the discontinuous layer (5) advantageously corresponding to a UV crosslinking ink and preferably being subjected to an active drying operation immediately after deposition. The applicant's documents WO2019219273 and WO2019243440 describe means for such implementation.

[0053] According to a practical embodiment of the invention, which is both simple and adaptable in terms of result, it is provided that the discontinuous layer (5) forming a decorative pattern and / or informative is formed in a single pass of the multi-head jet projection device, the degree of opacity of the pattern obtained being adjusted by adjusting the size of the drops of substance (5') projected and / or their possible mutual overlap.

[0054] Of course, the invention is not limited to the embodiments described and shown in the attached drawings. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Claims

1. Functional and / or decorative part (1), interior or exterior, for a vehicle, with a luminous pattern (2), only or particularly visible by backlighting, this part (1) comprising a transparent and self-supporting substrate layer (3), with opposite front (4) and rear (4') faces and comprising, on its rear face (4'), at least locally, a discontinuous layer (5) forming a decorative and / or informative pattern, resulting from an inkjet deposition of an optically opaque substance (5') and intended to be selectively exposed to lighting (6), said part (1) further comprising at least one transparent or translucent surface layer (7) covering the front face (4) of the substrate layer (3) and / or a layer (8) with occulting properties, preferably white in color, partially or totally covering the rear face (4') of the substrate layer (3) bearing the pattern (5).

2. Functional and / or decorative part according to claim 1, characterized in that the opaque substance (5'), for example a UV-crosslinking ink, has electrical conductivity properties, at least part of the decorative and / or informative pattern formed by the discontinuous layer (5) also constituting a functional component of the electromagnetic, electrical or electronic type.

3. Functional and / or decorative part according to claim 2, characterized in that the functional component formed by at least part of the decorative and / or informative pattern consists of an antenna for receiving, transmitting and / or transmitting an electromagnetic signal.

4. Functional and / or decorative part according to claim 2, characterized in that the functional component formed by at least part of the decorative and / or informative pattern consists of a proximity or contact detector, for example of the inductive, capacitive, mechano-electric or piezoelectric type.

5. Functional and / or decorative part according to any one of claims 1 to 4, characterized in that the discontinuous layer forming the decorative and / or informative pattern (5) is made up of successive deposits, by projection in superimposed layers, of droplets of the opaque substance (5') forming ink, made according to successive elementary deposition patterns, offset from each other and forming by accumulation said pattern (5), the surface of this pattern (5) being optically opaque or having translucency properties, where appropriate at least over one zone or region.

6. Functional and / or decorative part according to any one of claims 1 to 5, characterized in that the substrate layer (3) comprises on its rear face (4') a layer (9) of primer or bonding agent, at least translucent, preferably transparent, on which the discontinuous layer forming the decorative and / or informative pattern (5) is deposited.

7. Functional and / or decorative part according to any one of claims 1 to 6, characterized in that the transparent or translucent surface layer (7), covering the front face (4) of the substrate layer (3) and constituting the visible surface of the part (1), consists of a layer of protective varnish or lacquer.

8. Functional and / or decorative part according to any one of claims 1 to 6, characterized in that the transparent or translucent surface layer (7), covering the front face (4) of the substrate layer (3) and constituting the visible surface of the part (1), consists of an added layer, such as for example a film, a skin, a complex layer formed of a textile or a skin associated with an underlying comfort layer, foam or cellular material, or a plastic-coated fabric, this added surface layer being either overmolded onto said front face (4), or prefabricated and secured to said front face (4) by means of an adhesive layer (10), transparent or translucent, for example a layer of glue or a double-sided adhesive strip, of optical quality.

9. Functional and / or decorative part according to any one of claims 1 to 8, characterized in that the substrate layer (3) consists of a transparent plastic material, for example chosen from polycarbonate, polypropylene and polymethyl methacrylate.

10. Functional and / or decorative part according to any one of claims 1 to 9, characterized in that the layer (8) with occulting properties, preferably white in color, substantially opaque and covering either the entire rear face (4'), or at least the areas of the rear face (4') not comprising the layer discontinuous forming the decorative and / or informative pattern (5) or only the pattern (5), consists of a film, a layer of varnish, a layer of paint or a layer of ink, having where appropriate a constitution and a nature similar to those of the substance (5') forming said pattern (5).

11. Functional and / or decorative part according to any one of claims 1 to 10, characterized in that the different superimposed and constituent layers of said part (1) with a laminated structure respectively have the following thicknesses: substrate layer (3): thickness between 2 mm and 5 mm, discontinuous layer of substance (5') forming the pattern (5): thickness between 10 pm and 500 pm, surface layer (7): thickness between 0.5 mm and 2 mm and white layer (8): thickness between 10 pm and 1 mm.

12. Functional and / or decorative part according to any one of claims 1 to 11, characterized in that it constitutes with at least one lighting means (6) an arrangement or a structural component (11), intended to be mounted externally on or internally in a vehicle, where appropriate as a removable and interchangeable modular part.

13. Motor vehicle comprising at least one functional and / or decorative part (1) according to any one of claims 1 to 12, as an interior or exterior part, said vehicle also comprising at least one lighting means (6) for producing, selectively and by backlighting, a light pattern (2) on the visible face of said part (1), said part (1) and said lighting means (6) together forming a structural arrangement or component (11), possibly also integrating a technical function of an electromagnetic, electrical or electronic nature and constituting, where appropriate, a removable and interchangeable modular part of said vehicle.

14. A method of manufacturing a functional and / or decorative part (1), for interior or exterior mounting on a vehicle and having a light pattern (2) only visible by backlighting, for example a part according to any one of claims 1 to 12, said method comprising at least the following steps consisting of: - providing a transparent and self-supporting substrate layer (3), with opposite front (4) and rear (4') faces, shaped or molded to constitute the body of the part (1), - depositing on the rear face (4') of this substrate layer (3), at least locally, a discontinuous layer (5) forming a decorative and / or informative pattern using an inkjet deposition method of an opaque substance (5'), for example a UV-crosslinking ink, this deposition being controlled by a calculation and control means in accordance with a predetermined program, - applying or adding at least one transparent or translucent surface layer (7) so as to cover the front face (4) of the substrate layer (3) and / or a layer (8) with occulting properties, preferably white in color, so as to cover either the entire rear face (4'),either at least the areas of the rear face (4') not comprising the discontinuous layer forming the decorative and / or informative pattern (5), or only said pattern (5).,

15. Method according to claim 14, characterized in that it consists, in order to produce the discontinuous layer (5) forming the decorative and / or informative pattern, in projecting onto the rear face (4') of this substrate layer (3), by successive deposition phases and in superimposed layers, ink droplets (5') distributed surfacewise according to elementary droplet distribution patterns, predetermined and specific to each deposition phase, the successive depositions being carried out with mutual offsets between the patterns respectively applied and the successively projected droplets forming, by cumulative aggregation and crosslinking on the rear face (4'), said pattern (5).

16. Method according to claim 15, characterized in that it consists, depending on the shape of the pattern (5) sought, in defining for the successive deposition phases elementary droplet distribution patterns with alignments in two perpendicular directions, possibly producing a staggered distribution of the droplets of a pattern, and in shifting the elementary distribution patterns of two consecutive deposition phases by a step corresponding to a fraction of the distance between two droplets, for example to half of this distance.

17. Method according to claim 15 or 16, characterized in that it consists of adjusting the size of the droplets or the number of successive deposition phases to form the discontinuous layer (5) as a function of the optical properties desired for the pattern that it forms, between opacity and relative translucency, and taking into account the optical opacity properties of the substance (5') constituting the sprayed ink.

18. Method according to any one of claims 14 to 17, characterized in that the white layer (8) is applied by projection onto the rear face (4'), covering it completely or not, namely covering or not covering the decorative and / or informative pattern (5), and implementing an inkjet deposition method similar to that used for producing said pattern (5).

19. Method according to any one of claims 14 to 18, characterized in that it consists of applying to the rear face (4') of the substrate layer (3) a layer (9) of primer or bonding agent, at least translucent, preferably transparent, before the deposition of the discontinuous layer (5) forming the decorative and / or informative pattern on this face (4').

20. Method according to any one of claims 14 to 19, characterized in that it consists of depositing a layer of protective varnish or transparent or translucent lacquer on the front face (4) of the substrate layer (3) to form the visible surface layer (7) of the part (1).

21. Method according to any one of claims 14 to 19, characterized in that it consists in providing and adding as a transparent or translucent surface layer (7), intended to cover the front face (4) of the substrate layer (3) and to constitute the visible surface of the part (1), a film, a skin, a complex layer formed of a textile or a skin associated with an underlying comfort layer, foam or cellular material, or a plastic-coated fabric, this added surface layer being either overmolded onto said front face (4), or added as a prefabricated layer and secured to said front face (4) by means of an adhesive layer (10), transparent or translucent, for example a layer of glue or a double-sided adhesive strip, of optical quality.

22. Method according to any one of claims 14 to 21, characterized in that it consists, at least for the deposition of the

23. discontinuous layer (5) forming the decorative and / or informative pattern, and possibly also for the deposition of the back layer with occulting properties (8) and / or for the deposition of the translucent or transparent surface layer (7), moving the substrate layer (3), for example with a six-axis robotic arm, in front of a multi-head jet projection device, the projection of the substance intended to form the layer in question (5, 7, 8) being controlled by a calculation and control means regulating the wave train and the projection speed of the drops in accordance with a predetermined program and as a function of the geometry of the substrate layer (3) and its position and its speed of movement relative to said projection device,the substance (5') at least of the drops forming the discontinuous layer (5) advantageously corresponding to a UV crosslinking ink and preferably being subjected to an active drying operation immediately after deposition., Method according to any one of claims 14 to 22, characterized in that the discontinuous layer (5) forming a decorative and / or informative pattern is formed in a single pass of the multi-head jet projection device, the degree of opacity of the pattern obtained being adjusted by adjusting the size of the drops of substance (5') projected and / or their possible mutual overlap.

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