Motor vehicle component comprising an opaque coating, associated manufacturing method and lighting device comprising said component

Abstract

The invention relates to a component (1) for a motor vehicle, comprising a polymer-based body (10) having a surface (100) and an opaque coating (11) covering at least one portion of said surface (100). The coating is formed by at least one thin layer based on iron, comprising at least iron oxide and iron nitride; and the coating has a thickness greater than or equal to 100 nm over at least 50% of said at least one portion of said surface (100). Furthermore, the coating (11) has an absorption of incident light radiation greater than 70% of the incident light radiation. Thus, the coating provides the surface (100) of the component with reliable and reproducible opacity.

Description

Technical Field

[0001] The present invention relates to the field of components for motor vehicles. The invention has a particularly advantageous application in the field of signalling and lighting for motor vehicles. Background Art

[0002] In order to display a pattern or visual element on the surface of a component of a motor vehicle, an opaque coating that partially covers the surface of the component can be used. The pattern or visual element then appears due to the contrast between the opaque coating and the surface of the component.

[0003] For example, in lighting and / or signaling devices, the coating, which is also often referred to as a mask (also called a "bezel"), can be arranged, for example, on a reflector or on a decorative part of the device. When the device is then switched on, a light pattern can appear, for example to form the light signature of a motor vehicle model.

[0004] One commonly used solution involves applying a layer of black paint to the component's surface. This layer is then etched, for example by laser ablation, to reveal the pattern. However, the typical thickness of the paint layer is approximately 30 μm, which necessitates long laser ablation times and, consequently, significant investment in laser ablation equipment. Furthermore, applying the paint results in significant emissions of environmentally harmful volatile organic compounds.

[0005] As an alternative, JP 2008 / 077929(A) discloses a lighting device for motor vehicles in which a resin substrate is covered with a coating consisting of a thin layer of iron or an iron alloy with a thickness of less than or equal to 10 nm. The substrate and resin assembly is treated by thermal annealing to adjust the color of the oxidized coating. However, thermal annealing can cause cracks in the coating or even damage the substrate. To avoid this, the coating thickness is limited, thereby limiting its opacity.

[0006] It is therefore an object of the present invention to propose a component for a motor vehicle comprising an improved, reliable and reproducible opaque coating.

[0007] By reviewing the following description and the accompanying drawings, other objects, features and advantages of the present invention will become apparent. It will be understood that other advantages may be combined. Summary of the Invention

[0008] To achieve this object, according to a first aspect, there is provided a component for a motor vehicle, the component comprising:

[0009] - a polymer-based body having a surface;

[0010] - an opaque coating covering at least a portion of said surface.

[0011] Advantageously:

[0012] - said coating is formed by at least one thin layer based on iron and comprising at least one compound from the group consisting of iron oxide and iron nitride; and

[0013] - said coating has a thickness greater than or equal to 100 nm over at least 50% of said at least one portion of said surface.

[0014] Advantageously, the coating exhibits an absorption of incident radiation of substantially greater than 70%, preferably substantially greater than 80%, and even more preferably substantially greater than 90%. This radiation may in particular be in the visible range. Alternatively or additionally, the coating exhibits a reflection of incident radiation of substantially less than 30%, preferably substantially less than 20%, and even more preferably substantially less than 10%.

[0015] Black iron oxide and / or iron nitride allows thin layers to be opaque relative to layers based on unoxidized or unnitrided iron. Furthermore, this opacity is provided primarily by absorption of incident light radiation, rather than by reflection of this radiation. Consequently, the coating has a dark color and a non-metallic appearance. The layer is sufficiently thick over a large portion of the coated surface to provide good opacity to the component surface. Furthermore, the thickness of the layer allows good opacity to be provided for a group of components, regardless of any variations in thickness between the components during their manufacture. Consequently, the opaque coating is reliable and reproducible. The material cost of the layer is also lower than that of conventional coatings, thereby reducing the cost of the component.

[0016] Optionally, the component may further have at least one of the following features, which may be adopted individually or in combination.

[0017] The opaque coating may be configured to form at least one opaque region adjacent to the at least one portion of the surface and to form at least one non-coated region. The opaque coating only partially covers the surface of the body of the component so as to display a pattern or visual element on the surface of the component.

[0018] The body may be at least partially transparent, or even transparent. In conjunction with the opaque coating being configured to form at least one opaque region adjacent to at least one portion of the coated surface and at least one uncoated region, the opaque region blocks light transmission, while the uncoated region forms a pass-through region that allows light transmission. The uncoated region may form a light exit diopter in the light emitting device.

[0019] The component may be a component of a lighting and / or signaling device of a vehicle, in particular a reflector, a decorative element or a closed outer lens.

[0020] A second aspect of the invention relates to a lighting device for a motor vehicle, comprising the component for a motor vehicle according to the first aspect and a light source, the lighting device being used for at least one function selected from a lighting function and a signaling function.

[0021] The body of the component may be at least partially transparent, or even transparent, and the opaque coating may be configured such that at least one opaque area is formed adjacent to the at least one portion of the surface and at least one non-coated area is formed, and wherein the non-coated area forms a light exit diopter.

[0022] The component may be a decorative element for a headlamp. In this case, and in accordance with the previous paragraph, a signaling function may be performed by the non-coated area. For example, the signaling function may be a direction indicator, a position light (also known as a "parking light"), and / or a daytime running light (DRL).

[0023] According to the invention, the component can be an element of an interior lighting device of a vehicle, such as a ceiling or an illuminated trim of the passenger compartment, and / or the component can be a panel or part of a panel of an information display device, in particular an instrument panel.

[0024] A third aspect of the present invention relates to a vehicle equipped with the lighting device according to the second aspect of the present invention.

[0025] A fourth aspect of the invention relates to a method for producing a component for a motor vehicle, comprising:

[0026] - supplying a polymer-based body having a surface;

[0027] - depositing at least once a thin layer based on iron on at least one portion of the surface to be opaque in a gaseous environment comprising at least one reactive gas selected from oxygen and nitrogen, such that the thin layer comprises at least one compound from the group consisting of iron oxide and iron nitride and has a thickness greater than 100 nm over at least 50% of the at least one portion of the surface, thereby forming an opaque coating.

[0028] By reacting at least one reactive gas with iron during deposition, the resulting thin layer comprises at least one compound selected from the group consisting of iron oxide and iron nitride, without the need for additional annealing. Consequently, compared to existing solutions, the layer thickness can be increased, thereby providing good opacity while minimizing or even avoiding the risk of cracking in the coating and damage to the component's bulk. The resulting opaque coating is thus reliable and reproducible. Furthermore, compared to applying a paint, the manufacturing method is less expensive, thereby reducing the cost of the component. Furthermore, compared to existing solutions, when depositing the thin layer, volatile organic compound emissions are reduced or even avoided, particularly since no annealing is performed, thereby reducing the environmental impact of the method.

[0029] According to one embodiment, the method may further include at least one of the following steps:

[0030] - applying a local mask to the surface before depositing the thin layer and subsequently removing the mask after depositing the thin layer; and

[0031] - Laser ablation of a portion of the deposited thin layer.

[0032] The opaque coating thus obtained forms at least one opaque area situated adjacent to at least one portion of the surface that is to be opaque and at least one non-coated area. In a manner synergistic with the laser ablation of the thin layer, the thickness of the deposited layer allows the laser ablation time to be reduced by a factor of three compared to the laser ablation time of the paint layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The objects, features and advantages of the present invention will become more apparent through the detailed description of an embodiment of the present invention, which is illustrated in the following drawings, in which:

[0034] [ Figure 1 ] Figure 1 An overall view of a component for a motor vehicle according to one embodiment of the invention is shown.

[0035] [ Figure 2 ] Figure 2 A schematic diagram shows a lighting device for a motor vehicle according to an embodiment of the present invention.

[0036] Figures 3 to 9 The steps of a method for manufacturing a component for a motor vehicle according to one embodiment of the present invention are schematically illustrated, and more specifically:

[0037] [ Figure 3 ] Figure 3 The diagram shows the setup of the subject;

[0038] [ Figure 4 ] Figures 4 to 6 illustrates the deposition of thin layers according to various embodiments;

[0039] [ Figure 5 ]

[0040] [ Figure 6 ]

[0041] [ Figure 7 ] Figure 7 Laser ablation of a thin layer is shown;

[0042] [ Figure 8A ] Figure 8A The application of a mask to the surface of a supplied body is illustrated;

[0043] [ Figure 8B ] Figure 8B The diagram shows Figure 8A Deposition of a thin layer after applying a mask as illustrated in FIG;

[0044] [ Figure 9 ] Figure 9 A component for a motor vehicle according to an embodiment of the present invention is shown. Figure 7 After laser ablation as shown or Figure 8B Schematic representation of the opaque coating obtained after mask removal is shown.

[0045] The accompanying drawings are provided by way of example and do not limit the present invention. They are schematic conceptual illustrations intended to facilitate understanding of the present invention and are not necessarily drawn to scale for actual application. In particular, the relative thicknesses of the thin layers and the main body do not reflect actual conditions. DETAILED DESCRIPTION

[0046] Before commencing a detailed review of embodiments of the present invention, optional features of the first aspect of the present invention are set out below, which features may optionally be used in combination or alternatively:

[0047] - the shape of the body of the component is at least two-dimensional, or even three-dimensional;

[0048] -The main body is opaque;

[0049] - the surface of the body has a color that is different from the color of the coating;

[0050] - the thin layer is in direct contact with at least one portion of the surface;

[0051] - the thin layer comprises, throughout the thickness of the thin layer, at least one compound from the group consisting of iron oxide and iron nitride;

[0052] the opaque coating has a thickness greater than or equal to 200 nm over at least 30% of at least one portion of the surface;

[0053] - the opaque coating has a thickness less than or equal to 1 μm and preferably less than or equal to 600 nm;

[0054] the opaque coating has, over at least 50% of at least one portion of the surface, a color defined by the L*, a* and b* parameters in the 1976 CIE L*a*b* color space, wherein:

[0055] o L* ranges between 20 and 55, and preferably between 25 and 50;

[0056] The range of oa* is between -5 and +5;

[0057] The range of ob* is between -5 and +5.

[0058] According to one example, L is substantially equal to 30. Therefore, the opaque coating is black. According to one example, L is substantially equal to 45. Therefore, the opaque coating is anthracite gray.

[0059] Optional features of the fourth aspect of the present invention are set out below, which features may optionally be used in combination or alternatively:

[0060] - In the range of 10 -4 mbar and 10 -1 mbar and preferably between 10 -3 mbar and 10 -2 mbar to deposit thin layers;

[0061] - the gaseous environment comprises oxygen, wherein the oxygen ratio ranges between 10% and 100%, and preferably between 20% and 80%;

[0062] - the gaseous environment comprises oxygen, wherein the oxygen ratio ranges between 10% and 25%, and preferably between 20% and 25%;

[0063] - the gaseous environment comprises oxygen, wherein the oxygen ratio ranges between 25% and 100%, and preferably between 25% and 80%;

[0064] - at least one reactive gas is diluted in an inert gas, for example in argon;

[0065] - at least one reactive gas is a mixture of oxygen and nitrogen, and more particularly of air;

[0066] - The only reactive gas is oxygen;

[0067] -Deposition of thin layers is by physical vapor deposition;

[0068] The deposition of the thin layer may be a deposition selected from the following:

[0069] oPlasma-assisted thermal evaporation deposition;

[0070] o Electron beam physical vapor deposition (commonly referred to as EBPVD);

[0071] oCathode sputtering deposition.

[0072] It should be noted that within the scope of the present invention, expressions such as "equal to, less than, greater than" should be understood to indicate a comparison that can accommodate certain tolerances, particularly in terms of the dimensional ratios of the values ​​being compared and the uncertainty of measurement. Similarly, the expression "a range between..." indicates a range of values ​​that can accommodate certain tolerances, particularly in terms of the dimensional ratios of the values ​​in the range and the uncertainty of measurement. Essentially equal, lower, or higher values ​​are included within the scope of the present invention.

[0073] A parameter that is “substantially equal to / greater than / less than” a given value is understood to mean that the parameter is equal to / greater than / less than the given value, within a range of 10% to that value. A parameter that is “substantially in the range between two given values” is understood to mean that the parameter is at least equal to the smallest given value, within a range of 10% to that value, and at most equal to the largest given value, within a range of 10% to that value.

[0074] An element based on material A is understood to mean that the element comprises this material A and optionally other materials.

[0075] Throughout the entire description below, thickness is generally measured in a direction perpendicular to the upper plane of the substrate on which the layer is disposed. Therefore, in the cross-sectional views shown, thickness is generally taken in the vertical direction.

[0076] A “partially transparent” element is understood to mean that the element is configured to at least partially transmit incident light, and more specifically, to transmit at least 20%, or even at least 40%, or even at least 50%, or even at least 70% of the incident light, wherein these light rays are in particular in the visible range.

[0077] Now refer to Figure 1 、 Figure 2 and Figure 9 To describe components used in motor vehicles.

[0078] A component 1 for a motor vehicle includes a body 10. The body 10 has a surface 100, at least a portion 1000 of which is covered by an opaque coating 11. The opaque coating 11 is configured to at least partially obscure the surface 100 of the body 10. Thus, the appearance or properties of the surface 100, such as its diffusion, reflection, and / or light transmission properties, can be masked. More specifically, the opaque coating covers at least a portion 1000 of the surface 100, or even a plurality of portions 1000, so as to reveal a pattern or visual element on the surface 100 of the component 1.

[0079] like Figure 1 and Figure 9 As shown, the coating 11 may form at least one opaque region 111 or even a plurality of opaque regions, and at least one non-coated region 112 or even a plurality of non-coated regions 112 on the surface 100 of the component. The opaque region 111 and the coated region 112 may form a visual element or pattern by contrast.

[0080] like Figure 1 As illustrated, the component 1 may be a trim piece of a vehicle headlamp, for example intended to be placed below or above a lighting module.

[0081] The component 1 may be included in a lighting device 2 for a motor vehicle, for example being mounted by means of a fastening element 12. The lighting device 2 comprises a light source 20 and provides a lighting function and / or a signaling function.

[0082] The lighting device 2 may be a signaling module, integrated into a rear light of a vehicle, or even, as is the case here, into a headlight (also called a headlamp) of a vehicle.

[0083] according to Figure 2 In the illustrated non-limiting example, the lighting device 2 is a signaling module that is incorporated into a headlamp and comprises a light source 20 (eg a light emitting diode), a reflector 21 arranged facing the light source 20 , and an exit diopter.

[0084] According to an example not shown, component 1 may be a reflector 21 of a light emitting device 2. The opaque areas 111 of coating 11 may prevent light from being reflected by reflector 21, and the non-coated areas 112 may allow such reflection.

[0085] according to Figure 2 In the example illustrated in , the component 1 can be included in, or even form, the exit diopter of the light emitting device 2. The opaque areas 111 of the coating 11 can prevent the transmission of light from the reflector 21. The non-coated areas can allow such transmission and thus the lighting function. Figure 1 In FIG, such a separate component 1 can be seen, which forms the trim of the headlight and the exit screen for the signaling modules (eg direction indicators, position lights and / or daytime running lights).

[0086] According to one example, the coating is arranged on the inner face of component 1 in order to protect it from possible impacts and bad weather. Thus, the life of the coating 11 can be increased, and accordingly the life of component 1. According to another example, the coating is arranged on the outside of component 1. Component 1 can then be arranged inside an assembly (e.g., a sealed assembly). The coating can then be protected from possible impacts and bad weather. When component 1 is included in the output diopter of the light-emitting device 2, or even forms the output diopter, it is preferred to arrange the coating on the outside of component 1. This thereby prevents any elements present in the thickness of component 1 from being visible. In addition to or instead of arranging component 1 in the assembly, the coating can be covered with a protective layer that is configured to withstand possible impacts and bad weather. For example, the protective layer is a colorless or colored varnish.

[0087] The body 10 of the component 1 will now be described in detail. The body 10 is based on a polymer, or even on a plurality of polymers. The polymer may be chosen from among polycarbonate, polymethyl methacrylate, polybutyl methacrylate, polypropylene, polyamide, polyethylene, polyether, polyester resins, epoxy resins, polyurethanes and other thermoplastic and thermosetting materials, uncoated or previously coated with one or more polymer sublayers, and derivatives thereof. For example, polycarbonate has excellent mechanical properties and heat resistance, allowing use over a wide temperature range, typically between -100°C and 130°C, or even up to 180°C for "high temperature" grades of polycarbonate. ° C, which is particularly advantageous for component 1 for use in motor vehicles. It should be noted that body 10 may include other materials (e.g., fillers and / or reinforcements), thereby forming a composite material. Body 10 of component 1 may also have at least a two-dimensional, or even three-dimensional, shape. When component 1 is included in or even forms the output diopter of a light emitting device 2, body 10 is preferably three-dimensional.

[0088] According to one example, the body 10 may be opaque. The surface 100 of the body 10 may have a different color from the coating 11 to display a visual element or pattern that contrasts between the non-coated area 112 and the opaque area 111 on the surface 100.

[0089] Alternatively, the body 10 may be partially transparent or even transparent. The coating 11 may form at least one opaque region 111 and at least one non-coated region 112. The opaque region 111 allows light transmission to be blocked on the surface 100 of the body 10, and the non-coated region 112 forms a pass-through region that allows light transmission and thus may form an exit diopter.

[0090] The body 10 may also comprise a diffusing filler, in particular in order to form an exit diopter that diffuses the transmitted light.

[0091] The coating 11 will now be described in detail. The coating 11 is formed of at least one thin layer 110. The coating 11 is configured to make at least one coated portion 1000 of the surface 100 opaque. Preferably, the portion 1000 coated by the coating cannot be seen by the user, and more particularly, the color of the portion 1000 can be obscured. Figure 9 As illustrated, thin layer 110 may be in direct contact with surface 100 .

[0092] The thin layer 110 is based on iron and comprises at least one compound from the group consisting of iron oxide and iron nitride. The black color of the iron oxide and / or iron nitride allows the layer 110 to be darker and thus effectively opaque, having a metallic appearance, compared to layers based on unoxidized or nitrided iron.

[0093] More specifically, coating 11 is configured to render component 1 opaque primarily through light absorption, rather than through reflection, as is the case with existing solutions for rendering components opaque by bleaching or by a mirror effect. To this end, coating 11 can be configured to have an absorption of incident radiation substantially greater than 70%. More specifically, the incident radiation lies in the visible range. According to one example, the coating has an absorption of incident radiation substantially greater than 80%. Thus, the coating has a grayish color, and component 1 has satisfactory opacity. According to one example, the coating has an absorption of incident radiation substantially greater than 90%. Thus, the coating has a black color, and component 1 has satisfactory opacity. According to alternative or additional examples, coating 11 can be configured to have a reflection of incident light radiation substantially less than 30%, preferably substantially less than 20%, and even more preferably substantially less than 10%.

[0094] The color of the coating 11 can be described in the 1976 CIE L*a*b* color space, which is commonly used to characterize surface colors. In this space, three parameters characterize color: lightness L* describes the luminosity of the surface; the two parameters a* and b* represent the deviation of the color from a gray surface of the same lightness. Preferably:

[0095] - L* ranges between 20 and 55, and preferably between 25 and 50;

[0096] -a* ranges between -5 and +5;

[0097] -b* ranges between -5 and +5.

[0098] Thus, the coating 11 has a gray to black color, thereby ensuring effective opacity of the coated portion 1000. For example, L* is substantially equal to 30, which corresponds to black. According to another example, L* is substantially equal to 45, which corresponds to gray, and more specifically anthracite gray. A method for measuring the color of the coating 11 in the 1976 CIE L*A*b* color space involves using a spectrophotometer in contact with the coating. The values ​​of L*, a*, and b* are measured by a spectrophotometer. For example, a Konica CM-700 or CM-2600 spectrophotometer.

[0099] Coating 11 has a thickness E greater than or equal to 100 nm over at least 50% of coated portion 1000. Thus, this layer is sufficiently thick to provide good opacity of coated portion 1000 over a substantial portion of portion 1000. Furthermore, this thickness allows for good opacity to be provided to a group of components 1, regardless of any variations in thickness between these components 1 when layer 110 is deposited, as will be described below. Consequently, opaque coating 11 is reliable and reproducible. More specifically, thickness E of coating 11 may be greater than or equal to 200 nm over at least 30% of coated portion 1000. Thus, layer 110 provides even better opacity of coated portion 1000. Thickness E of the coating may be less than or equal to 1 μm, and preferably less than or equal to 600 nm, in order to minimize the costs associated with producing coating 11.

[0100] Further features of the coating 11 are described below in the description of the method for producing the component 1 .

[0101] Now refer to Figures 3 to 9 A method for producing the component 1 is described.

[0102] like Figure 3 As illustrated, the method comprises providing a body 10 according to the features described above.

[0103] The method then comprises at least one deposition of a thin layer 110 in order to obtain a layer 110 comprising at least one compound selected from the group consisting of iron oxide and iron nitride. To this end, the layer 110 can be formed by oxidizing and / or nitriding iron. For example, the iron can originate from a metal source based on iron evaporated during deposition, and the layer 110 can be formed by condensation of the metal after oxidation and / or nitridation. The metal source can be pure iron or an iron alloy, and more particularly, any type of steel, including stainless steel.

[0104] To allow oxidation and / or nitridation, deposition can be performed in a gas environment comprising at least one gas suitable for reacting with at least iron (this gas is also referred to as a reactive gas). The reactive gas can be diluted in a gas that does not react during deposition, also referred to as an inert gas, such as argon. The reactive gas can be selected from oxygen for oxidation reactions and nitrogen for nitridation reactions.

[0105] According to one example, the reaction gas is oxygen, optionally mixed with nitrogen and / or diluted in an inert gas. The gaseous environment may include oxygen, wherein the oxygen ratio ranges from 10% to 100%, and preferably from 20% to 80%. Depending on the oxygen ratio, the oxidation reaction between iron and oxygen can be adjusted.

[0106] The reduction in oxygen content leads to a lower reaction with iron, which allows the iron oxide concentration in the layer 110 to be reduced and a gray color to be obtained. Furthermore, the reduction in oxygen content allows the explosion risks associated with oxygen to be overcome. For example, the oxygen ratio can range from 10% to 25%, and preferably from 20% to 25%, in order to obtain a gray coating 11. The reaction gas can be a mixture of oxygen and nitrogen, wherein the oxygen ratio can be substantially equal to 20%. For example, the reaction gas is air, thereby minimizing the cost of the coating 11 and the cost of the deposition equipment.

[0107] By increasing the oxygen content, the oxidation reaction of iron is promoted, which allows to increase the iron oxide concentration in the layer 110. The oxygen ratio in the gaseous environment can range between 25% and 100%, and preferably between 25% and 80%, in order to obtain a black coating 11. In fact, with an oxygen content between 80% and 100%, the gaseous environment can be very reactive and cause yellow, red or blue reflections. In order to avoid any explosion risk caused by an oxygen content greater than 25%, the deposition equipment can include a safety unit, such as a dry pumping unit.

[0108] The deposition time and the pressure of the gas environment can be configured to adjust the thickness of the deposited layer 110. During deposition, the pressure can range from 10 -4 mbar and 10 -1mbar, and preferably between 10 -3 mbar and 10 -2 mbar (in the International System of Units, 1 mbar = 10 -3 bar = 100 Pa). Pressures above these ranges can lead in particular to inhomogeneities in the layer 110 and to the formation of rough deposits, giving the coating a powdery appearance. Pressures below this range may also be insufficient to allow the reaction between the iron and the reactive gas and thus give the layer 110 a metallic appearance. It should be noted that these parameters can be adjusted depending on the deposition technique used. The range is between 10 -4 mbar and 10 -1 Pressures between mbar are particularly suitable for electron beam physical vapor deposition. -3 mbar to 10 -2 Pressures between mbar are particularly suitable for plasma-assisted thermal evaporation and sputtering deposition.

[0109] like Figures 4 to 6 As shown, the layer 110 can be deposited on the upper surface 100 of the body 10. It should be noted that the layer 110 can also be deposited on the side surface 100 of the body 10. In addition, the body 10 can have a three-dimensional shape, for example with a material relief, and the layer 110 can be deposited on the surface 100 following its three-dimensional shape. Depending on the deposition technology used, the layer 110 can be compliant or non-compliant. The term "compliant" is understood to mean that the layer has a consistent thickness (with the closest manufacturing tolerances), regardless of how the direction of the layer 110 changes. When the layer 110 is non-compliant, the thickness of the layer 110 can vary between different sections of the layer. Accordingly, it should be understood that only a portion of the layer 110 can have the thickness E described above.

[0110] The method may comprise depositing a plurality of thin layers 110, 110'. Figure 6 In the illustrated example, in particular, the deposition parameters can be adapted to adjust the concentration of iron oxide and / or iron nitride in the thin layer 110 between the individual layers 110, 110'. Alternatively or additionally, the deposition of the thin layer 110 can also be configured such that the layer 110 has a concentration gradient of iron oxide and / or iron nitride in the thin layer 110. In particular, the layer 110 can have a concentration gradient in a direction perpendicular to the surface 100 of the body.

[0111] To form the opaque areas 111 and the non-coated areas 112 , the method may comprise at least one process selected from: applying a local mask 3 to the surface 100 before depositing the thin layer 110 ; and laser ablating a portion 112 ′ of the deposited thin layer 110 .

[0112] like Figure 7 As shown, the deposited layer 110 may be subjected to laser radiation in order to etch the layer 110. The laser radiation may be configured so as to etch a portion 112' of the layer 110 on the portion 1001 of the surface 100. Thus, the portion 1001 of the surface may be completely uncoated, such as Figure 9 According to an example not shown, the laser radiation can be configured so that the etching of the layer 110 is localized, for example, in order to obtain a gradient variation in the thickness E of the layer 110 between the non-coated areas 112 and the opaque areas 111. The power and the ablation time of the laser radiation can be particularly adapted to this purpose.

[0113] like Figure 8A As shown, the method may comprise applying a mask 3 to a portion 1001 of the surface 100 intended for non-coating. The layer 110 may then be deposited on the assembly formed by the body 10 and the mask 3, as shown. Figure 8B By removing the local mask 3, an opaque area 111 and a non-coated area 112 are formed, as shown in FIG. Figures 8B to 9 The transformation is illustrated.

[0114] Layer 110 can be deposited using physical vapor deposition techniques. Layer 110 can be deposited using plasma-assisted thermal evaporation. Thermal evaporation deposition is faster and is therefore particularly suitable for high-thickness thin layer deposition. Plasma also allows oxidation and / or nitridation reactions to occur between iron and the reaction gas environment. During plasma-assisted thermal evaporation deposition, the first deposited atomic layer can have a higher iron concentration than the oxygen concentration or even the concentration of oxygen and nitrogen (if applicable). As iron is deposited, the iron concentration and the oxygen element concentration and the concentration of nitrogen (if applicable) can be balanced to achieve a stoichiometric ratio of iron oxide and / or nitride, and thereby form a concentration gradient in layer 110 in a direction perpendicular to the surface 100 of the body 10.

[0115] Layer 110 can be deposited using electron beam physical vapor deposition. Depending on the power of the electron beam, electron beam physical vapor deposition allows the deposition rate of the thin layer to be adjusted, thereby adjusting the characteristics of the resulting layer. For example, the first layer 110 can be deposited at a fast rate. The oxidation or nitridation reaction of the iron may be incomplete. Layer 110 can then have a higher iron concentration than the oxygen concentration or even the oxygen and nitrogen concentrations (if applicable). The second layer 110 can then be deposited at a lower rate in order to obtain a final layer 110 that exhibits a good stoichiometric ratio and thus ensures opacity through the coating 11.

[0116] The layer 110 can be deposited by reactive cathode sputtering. Atomic sputtering deposition is relatively fast and is therefore particularly suitable for the deposition of thin layers of high thickness. In addition, the thin layer 110 obtained can have better adhesion, because the ions generated during cathode sputtering have sufficient energy to be slightly implanted in the surface 100 of the body 10. In addition, using this technology, the thin layer 110 maintains the stoichiometric ratio of the elements of the source material, thereby allowing the characteristics of the obtained layer to be adjusted. According to one example, the layer is deposited by magnetron cathode sputtering. The metal source is then a non-magnetic source and is made of stainless steel, for example. Due to the presence of chromium in this metal source, the reaction between iron and oxygen is limited, resulting in the gray color of the coating 11.

[0117] By way of example, the mode of operation of the method will now be described, wherein a thin layer is deposited by plasma-assisted thermal evaporation, wherein:

[0118] - performing thermal evaporation with a voltage supply ranging between 1 V and 10 V, preferably between 3 V and 7 V, and a current supply ranging between 100 A and 10,000 A, preferably substantially ranging between 500 A and 3,000 A;

[0119] the plasma is powered by direct current, or by medium-frequency alternating current (e.g. 40 kHz), or even by radiofrequency or by microwaves. When the plasma is powered by direct current or by medium-frequency alternating current (e.g. 40 kHz), the plasma is supplied with a voltage ranging from 500 V to 10,000 V, preferably from 2,000 V to 6,000 V, and a current ranging from 0 mA to 5,000 mA, preferably from 50 mA to 1,000 mA;

[0120] - the evaporation time ranges between 50 seconds (s) and 1000 seconds, preferably between 150s and 400s;

[0121] -The pressure range is between 10 -4 mbar and 10 -1 mbar, preferably between 10 -3 mbar and 10 -2 mbar.

[0122] In view of the above description, it is evident that the present invention proposes a component for a motor vehicle comprising an improved, reliable and reproducible opaque coating.

[0123] The invention is not limited to the embodiments described above, but extends to all embodiments covered by the claims.

[0124] List of reference numerals

[0125] 1 part

[0126] 10 main body

[0127] 100 Surface

[0128] 1000 will be the opaque part

[0129] 1001 Non-coated part

[0130] 11 Opaque coating

[0131] 110 thin layer

[0132] 110 Second Thin Layer

[0133] 111 opaque area

[0134] 112 non-coated area

[0135] 112' thin layer section

[0136] 12 fastening elements

[0137] 2 Light-emitting device

[0138] 20 light sources

[0139] 21 reflectors

[0140] 22 output diopter

[0141] 3 masks

Claims

1. A component (1) for a motor vehicle, comprising: • a polymer-based body (10) having a surface (100); • an opaque coating (11) covering at least a portion (1000) of said surface (100); and Its characteristics are: • the coating is formed by at least one thin layer (110) based on iron and comprising at least one compound from the group consisting of iron oxide and iron nitride; and • said coating has a thickness (E) greater than or equal to 100 nm over at least 50% of said at least one portion (1000) of said surface (100); • The coating exhibits an absorption of incident optical radiation greater than 70% of the incident optical radiation.

2. The component (1) according to claim 1, wherein The opaque coating (11) is configured such that at least one opaque region (111) is formed near the at least one portion (1000) of the surface (100), and at least one non-coated region (112) is formed.

3. The component (1) according to any one of claims 1 and 2, wherein The opaque coating (11) has a thickness (E) greater than or equal to 200 nm over at least 30% of the at least one portion (1000) of the surface (100).

4. The component (1) according to any one of claims 1 and 2, wherein The opaque coating (11) has a thickness (E) less than or equal to 1 μm.

5. The component (1) according to any one of claims 1 and 2, wherein The body (10) is at least partially transparent.

6. Component (1) according to any one of claims 1 and 2, wherein The opaque coating (11) has a color defined by L*, a*, and b* parameters in the 1976 CIE L*a*b* color space on at least 50% of the at least one portion (1000) of the surface (100), wherein: •L* ranges between 20 and 55; •a* ranges from -5 to +5; •b* ranges from -5 to +5.

7. A lighting device (2) for a motor vehicle, comprising a component (1) for a motor vehicle according to any one of claims 1 to 6 and a light source (20), the lighting device (2) being used for at least one function selected from a lighting function and a signaling function.

8. The lighting device (2) according to claim 7, wherein: The body (10) is at least partially transparent, and the opaque coating (11) is configured such that at least one opaque region (111) is formed adjacent to the at least one portion (1000) of the surface (100) and at least one non-coated region (112) is formed, wherein the non-coated region (112) forms an exit diopter (22).

9. A method for manufacturing a component (1) for a motor vehicle, comprising: • supplying a polymer-based body (10) having a surface (100); • Depositing an iron-based thin layer (110) at least once on at least one portion (1000) of the surface (10) to be opaque in a gas environment comprising at least one reactive gas selected from oxygen and nitrogen, such that the thin layer (110) comprises at least one compound from the group consisting of iron oxide and iron nitride, and the thin layer (110) has a thickness (E) greater than 100 nm on at least 50% of the at least one portion of the surface, thereby forming an opaque coating (11).

10. The method according to claim 9, further comprising at least one of the following steps: • applying a local mask (3) to the surface (100) before depositing the thin layer (110), and subsequently removing the mask (3) after depositing the thin layer (110); and • Laser ablation of a portion (112') of the deposited thin layer (110).

11. The method according to any one of claims 9 and 10, wherein: In the range of 10 -4 mbar and 10 -1 The thin layer (110) is deposited at a pressure between mbar and mbar.

12. The method according to any one of claims 9 and 10, wherein The gas environment includes oxygen, wherein the oxygen ratio ranges between 10% and 100%.

13. The method according to any one of claims 9 and 10, wherein: The gas environment includes oxygen, wherein the oxygen ratio ranges between 10% and 25%.

14. The method according to any one of claims 9 and 10, wherein The gas environment includes oxygen, wherein the oxygen ratio ranges between 25% and 100%.

15. The method according to any one of claims 9 and 10, wherein: The thin layer (110) is deposited by physical vapor deposition selected from the following: •Plasma-assisted thermal evaporation deposition; •Electron beam physical vapor deposition; •Cathode sputtering deposition.

16. The method according to claim 12, wherein: The oxygen ratio ranges between 20% and 80%.

17. The method according to claim 13, wherein: The oxygen ratio ranges between 20% and 25%.

18. The method according to claim 14, wherein The oxygen ratio ranges between 25% and 80%.

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