METHOD FOR MANUFACTURING A TRANSPARENT OR TRANSLUCENT VEHICLE PART

Abstract

A method for manufacturing a vehicle part, including the steps of a) overmolding a semi-transparent film on a transparent or translucent part, b1) applying a paint layer on the semi-transparent film, b2) applying a varnish layer on the paint layer, and b3) partially irradiating the paint layer and the varnish layer with laser radiation so as to etch the paint layer and the varnish layer, step a) being implemented before step b1) or after step b3).

Claims

1. A method for manufacturing a vehicle part, characterized in that it comprises the following steps: a) overmolding a semi-transparent film on a transparent or translucent part, b1) applying a paint layer on the semi-transparent film, b2) applying a varnish layer on the paint layer, and b3) partially irradiating the paint layer and the varnish layer with laser radiation so as to etch the paint layer and the varnish layer.

2. The method according to claim 1, wherein the following step is implemented before step b1): b0) applying a protective layer on the semi-transparent film, under the paint layer.

3. A method for manufacturing a vehicle part, characterized in that it comprises the following steps: b1) applying a paint layer on a semi-transparent film, b2) applying a varnish layer on the paint layer, b3) partially irradiating the paint layer and the varnish layer with laser radiation so as to etch the paint layer and the varnish layer, and a) overmolding the semi-transparent film on a transparent or translucent part.

4. The method according to claim 1, wherein the transparent or translucent part is manufactured by molding a plastic.

5. The method according to claim 4, wherein the plastic is polycarbonate, polypropylene, polyethylene terephthalate or poly(methyl methacrylate).

6. The method according to claim 1, wherein the laser radiation has a wavelength in the infrared, preferably the near infrared, or the ultraviolet.

7. The method according to claim 1, wherein the laser radiation has a wavelength in the near infrared.

8. The method according to claim 1, wherein the semi-transparent film has a visual effect chosen from the following list: chrome, metallic, shiny, matte, satin, brushed or copper, mirror effect.

9. The method according to claim 1, wherein the semi-transparent film comprises a stack of layers made of polyethylene terephthalate.

10. The method according to claim 1, wherein the semi-transparent film has a thickness of between 100 μm and 1 mm.

11. The method according to claim 1, wherein the transparent or translucent part has at least one main shape in relief under the semi-transparent film.

12. The method according to claim 11, wherein the laser irradiation of step b3) is carried out at least opposite the at least one main shape in relief.

13. The method according to claim 11, wherein the transparent or translucent part comprises a first face on which the semi-transparent film is overmolded and having the at least one shape in relief, and a second face opposite the first face, the second face having at least one secondary shape in relief opposite the main shape in relief and of opposite convexity.

14. A vehicle part, characterized in that it is obtained by implementing a manufacturing method according to claim 1.

15. A vehicle part, characterized in that it is obtained by implementing a manufacturing method according to claim 3.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0045] The invention will be better understood upon reading the description which follows, given solely by way of example and with reference to the appended drawings, in which:

[0046] FIG. 1 is a sectional view of a first step in the implementation of a method for manufacturing a vehicle part according to a first embodiment of the invention,

[0047] FIG. 2 is a sectional view of a second step in the implementation of a method for manufacturing the vehicle part according to the first embodiment of the invention,

[0048] FIG. 3 is a sectional view of a vehicle part resulting from the implementation of a manufacturing method according to a second embodiment of the invention,

[0049] FIG. 4 is a sectional view of a vehicle part resulting from the implementation of a manufacturing method according to a variant of the second embodiment of the invention,

[0050] FIG. 5 is a sectional view of a vehicle part resulting from the implementation of a manufacturing method according to a third embodiment of the invention,

[0051] FIG. 6 is a perspective view of the vehicle part of FIG. 5, and

[0052] FIG. 7 is a sectional view of a vehicle part resulting from the implementation of a manufacturing method according to a variant of the third embodiment of the invention.

DETAILED DESCRIPTION

[0053] FIG. 1 shows a first step of a method for manufacturing a vehicle part 2 according to a first embodiment of the invention.

[0054] The vehicle part 2 comprises a transparent or translucent part 4 that is intended to protect a light source (not shown). The term “transparent,” “translucent,” respectively, is understood to mean that it is at least transparent to any light radiation having a wavelength within the visible spectrum, i.e., between approximately 380 and 780 nm. The transparent part 4 is made here of a plastic having this characteristic—in this case polycarbonate, commonly called “PC.” However, a provision can be made to produce the part from any other plastic, such as polypropylene (PP) (translucent), polyethylene terephthalate (PET) (translucent) or poly(methyl methacrylate) (PMMA) (transparent). The transparent or translucent part 4 is made by molding. Since such a method is known, we will not go into further detail about it in the following.

[0055] The vehicle part 2 comprises a semi-transparent film 6 that is overmolded on a first face 8 of the transparent part 4. The first face 8 forms the external surface of the transparent part 4. The term “external surface” is understood to mean a surface of the transparent part 4 that is not situated opposite the light source and that is intended to be exposed to the external environment once the vehicle has been manufactured. The transparent part 4 further has a second face 10, forming the internal surface of the transparent part 4, opposite the first face 8. In other words, the light emitted by the light source first encounters the second face 10, then the first face 8, before entering the external environment.

[0056] The semi-transparent film 6 is defined as such in that it allows the transmission of the light emitted by the light source, with possible partial absorption of this light, but prevents the transmission of natural light. Here, the semi-transparent film 6 comprises a stack of layers made of polyethylene terephthalate (PET) such that the semi-transparent film 6 has a thickness of between 100 μm and 1 mm. This stack of layers makes it possible to give the semi-transparent film 6 a chrome appearance, but it is possible to replace the stack of layers made of polyethylene terephthalate with a completely different stack to give another appearance to the semi-transparent film. For example, it is possible to choose the constitution of the semi-transparent film so that it has a visual effect chosen from the following list: chrome, metallic, shiny, matte, satin, brushed or copper, mirror effect. The semi-transparent film 6 has a simple shape, devoid of openings, covering the entirety of the first face 8 or at the very least a portion of it. It will be seen below how these properties of the semi-transparent film 6 are of interest in the context of the invention.

[0057] The vehicle part 2 here comprises a protective layer 12 that is deposited on the semi-transparent film 6. The protective layer 12 here comprises a varnish layer and protects the transparent part 4 from any ultraviolet radiation to which it may be exposed, particularly from the sun. In addition, the protective layer 12 makes it possible to mechanically protect the transparent part 4, particularly to prevent it from being scratched or deformed by external stresses. In absolute terms, the presence of the protective layer 12 is optional. The protective layer 12 is transparent to any light radiation having a wavelength in the visible spectrum, so as not to prevent the transmission of the light emitted by the light source through the vehicle part 2.

[0058] The vehicle part 2 comprises a paint layer 14 that is deposited over the protective layer 12. Here, the paint layer 14 comprises a primer undercoat 16 onto which a base layer 18 is deposited. The base layer 18 makes it possible to color the external appearance of the vehicle part 2. The primer undercoat 16 improves the opacity of the paint layer 14 and improves the adhesion of the base layer 18 to the transparent part 4.

[0059] The vehicle part 2 comprises a varnish layer 20 that is deposited over the paint layer 14. The varnish layer 20 makes it possible to protect the transparent part 4 and the paint layer 14 from any ultraviolet radiation to which they may be exposed. Here, the protective layer 12 and varnish layer 20 are made of the same material, but a provision can be made to use two different varnishes to produce the two layers 12, 20.

[0060] To deposit the semi-transparent film 6 and the different layers on the transparent part 4, the following steps shown in FIG. 1 are implemented: [0061] a) overmolding the semi-transparent film 6 on the transparent part 4, [0062] b0) applying the protective layer 12 on the semi-transparent film 6, [0063] b1) applying the paint layer 14 on the protective layer 12, and [0064] b2) applying the varnish layer 20 on the paint layer 14.

[0065] Among the steps listed above, steps b0), b1) and b2) are carried out successively. Step a) is carried out independently of the prior implementation of steps b0), b1) and b2). Provision can thus be made to implement step a) of overmolding the semi-transparent film 6, bare, on the transparent part 4, then to apply the layers according to steps b0), b1) and b2) on the overmolded semi-transparent film 6. It is also possible to apply the layers according to steps b0), b1) and b2) on the semi-transparent film 6, then to overmold the assembly on the transparent part 4 according to step a).

[0066] FIG. 2 shows a following step of the method for manufacturing the vehicle part 2. In this step b3), a portion of the vehicle part 2 is irradiated using laser radiation 22 so as to etch the paint layer 14 and the varnish layer 20. This etching is carried out throughout the thickness of the paint layer 14 and the varnish layer 20. This operation is commonly referred to as “laser etching.” In the context of the invention, the laser radiation 22 has a wavelength in the infrared, i.e., between 700 nm and 20,000 nm. One example of such laser radiation is that commonly referred to as “CO.sub.2 laser,” which has a wavelength of 10,600 nm. Preferably, the wavelength of the laser radiation 22 is in the near infrared, i.e., between 700 and 2,000 nm. In this case—and if the protective layer 12 and the varnish layer 20 are transparent to laser radiation 22—the latter range has the advantage of not etching said layers. This avoids the risk of damaging said layers, in particular the protective layer. Alternatively, provision can be made for the laser radiation to have a wavelength in the ultraviolet.

[0067] The irradiation is carried out in only a portion of the vehicle part 2 in the sense that it is carried out according to a predefined pattern of the external surface of the varnish layer 20. It is controlled in such a way that the varnish layer 20 and the paint layer 14 are irradiated and hence eliminated in the pattern and throughout their thickness, but not the protective layer 12, which protects the transparent part 4 from ultraviolet radiation in the regions of the pattern that have been etched, or the semi-transparent film 6. Even if the varnish layer 20 is made of a material that is transparent to laser radiation 22, the irradiation of the underlying paint layer 14 makes it possible to eliminate the varnish layer 20 in the pattern.

[0068] After irradiation, the surface of the vehicle part 2 has two levels.

[0069] In the region of the predefined pattern, the transparent part 4 is coated only with the semi-transparent film 6 and the protective layer 12. In this region, the light emitted by the light source can be transmitted from the light source to the external environment, but in the other direction the semi-transparent film limits the transmission of natural light to the light source. In this way, the light source and any wiring it may have are not visible from outside the vehicle when the light source is switched off.

[0070] Outside the region of the predefined pattern, the transparent part 4 is coated with the semi-transparent film 6, the protective layer 12, the paint layer 14 and the varnish layer 20. In this region, visible light cannot be transmitted from the external environment to the transparent part 4, and vice versa, because it is absorbed by the paint layer 14. In particular, the protection of the transparent part 4 from ultraviolet radiation to which it may be exposed is ensured by the varnish layer 20.

[0071] After this irradiation step, an additional step of polishing the vehicle part 2 can be provided. This improves transparency in the region of the predefined pattern and, more generally, the esthetics of the vehicle part 2. In addition, this polishing makes it possible to round the corners formed by the etching carried out during the irradiation step, and thus to improve the esthetics of the vehicle part 2 and its tactile surface quality.

[0072] It is possible to implement a variant embodiment in which steps b2) and b3) are inverted, so that the varnish layer is not etched by the laser irradiation. It is also possible to implement another alternative embodiment of the method according to which a step b4) is added, occurring after step b3) consisting in applying an additional varnish layer over the paint layer and the varnish layer that have been etched by laser irradiation.

[0073] FIG. 3 shows a vehicle part 2′ obtained by implementing a manufacturing method according to a second embodiment of the invention. Only the differences presented by the vehicle part 2′ compared to that of the first embodiment will be described in the following. Identical or similar elements from one embodiment to another bear identical reference numerals.

[0074] The vehicle part 2′ comprises a transparent part 4 having, on its first face 8, at least one so-called main relief shape 24 under the semi-transparent film 6. In the example of FIG. 3, it is in the form of a rounded convex bump, but it can take any desired shape, and in the desired number. Apart from the at least one main shape in relief 24, the first face 8 has a flat or curved shape. It is assumed in what follows that the transparent part 4 comprises several main shapes in relief 24, knowing that it could very well comprise a single main shape in relief.

[0075] The semi-transparent film 6, the protective layer 12, the paint layer 14 and the varnish layer 20 are deposited and etched in the same way as in the previous embodiment of the invention, by implementing steps a) and b0) to b3). Preferably, the laser irradiation of step b3) is carried out at least opposite the main shapes in relief 24. Thus, the pattern generated in the paint layer 14 and in the varnish layer 20 coincides with the main shapes in relief 24 of the transparent part 4. In this way, the light emitted by the light source passes into the pattern through the main shapes in relief 24, the semi-transparent film 6 and the protective layer 12, which makes it possible to generate a particularly esthetic light scattering, in particular for a person who is not directly in front of the vehicle part but who observes it from the side. This light scattering is illustrated in FIG. 3 by light rays 25 emitted from the light source that are refracted as they exit the main shapes in relief 24, thereby creating a prismatic light scattering effect.

[0076] FIG. 4 shows a vehicle part 2′ according to a variant of the second embodiment illustrated in FIG. 3. It differs therefrom in that the transparent part 4 has, on its second face 10, at least one so-called secondary shape in relief 26 located opposite a main shape in relief 24 considering a direction of thickness of the transparent part 4 that is vertical in FIG. 4. The secondary shape in relief 26 has a similar convexity with respect to the main shape in relief 24 that is opposite it. In the example of FIG. 4, the vehicle part 2′ comprises a main shape in relief 24 that is convex and a secondary shape in relief 26 that is also convex.

[0077] The arrangement of the main 24 and secondary 26 shapes in relief makes it possible to obtain a light distribution at the first face 8 of the transparent part 4 that is different from the one obtained with the vehicle part of FIG. 3. Through the convexity of the main 24 and secondary 26 shapes in relief, one obtains local concentrations of the light rays passing through the part 4 due to the refraction of the light rays 25 at the second face 10 then at the first face 8, thus creating a certain esthetic effect.

[0078] FIG. 5 shows a vehicle part 2″ obtained by implementing a manufacturing method according to a third embodiment of the invention. Only the differences presented by the vehicle part 2″ compared to that of FIG. 3 will be described in the following. Identical or similar elements from one embodiment to another bear identical reference numerals.

[0079] The vehicle part 2″ comprises a transparent part 4 having, on its second face 10, at least one so-called secondary shape in relief 26. Here, the transparent part 4 comprises as many secondary shapes in relief 26 as it comprises main shapes in relief 24. Each secondary shape in relief 26 is located opposite a main shape in relief 24 considering a direction of thickness of the transparent part that is vertical in FIG. 4, so that the set of secondary shapes in relief 26 is the image of the set of main shapes in relief 24 by a one-to-one function. Each secondary shape in relief 26 has an opposite convexity, but an identical shape and identical dimensions, with respect to the main shape in relief 24 that is opposite it. In the example of FIG. 5, the vehicle part 2″ comprises a convex main shape in relief 24 and a concave secondary shape in relief 26, of identical shape and dimensions so that two vehicle parts 2″ could be fitted together one into the other. In other words, the transparent part 4 has a uniform thickness. As in the previous figure, the light rays 25 illustrate the light scattering passing through the vehicle part 2″. The light rays 25 here are refracted twice and in the same direction, namely when they pass through the secondary shape in relief 26 and then when they pass through the main shape in relief 24.

[0080] The semi-transparent film 6, the protective layer 12, the paint layer 14 and the varnish layer 20 are deposited and etched in the same way as in the previous embodiments of the invention, by implementing steps a) and b0) to b3) and performing the laser irradiation of step b3) at least opposite the main shapes in relief. FIG. 6 in particular illustrates the state of the first face 8 of the vehicle part 2 once these steps have been carried out.

[0081] FIG. 7 shows a vehicle part 2″ according to a variant of the third embodiment illustrated in FIG. 5. It differs therefrom in that inside the secondary shape in relief 26, the second face 10 of the transparent part 4 comprises at least one so-called optical relief 28 configured to further alter the trajectory of some of the light rays 25 passing through the transparent part 4. The optical relief 28 here is in the form of a convex relief, generating a strong local concentration of the light rays leaving the vehicle part 2″ through the first face 8. However, any possible shape can be provided for the optical relief. By way of example, the shape of the optical relief may be such that it forms a collimator, a concave prism or a convex prism.

[0082] The invention is not limited to the embodiments described here, and other embodiments will become clearly apparent to a person skilled in the art.

[0083] To produce the pattern, the laser irradiation engraving technique can be replaced by concealing or masking techniques if the degree of precision of these techniques is satisfactory when implementing the invention. It is also possible to provide for the use of concealing or masking and then implementing engraving by laser irradiation in order to make the production of the pattern more precise.

[0084] The light source can be part of an optical unit of low and high beams of the vehicle, of an optical unit of turn signals of the vehicle, or of an optical unit of decorative lights.

[0085] Alternatively, the transparent part can incorporate light guides or light sources without an optical unit through insert molding, overmolding, fixing by gluing, welding, riveting, or by any other fixing means.

LIST OF REFERENCES

[0086] 2; 2′; 2″: vehicle part [0087] 4: transparent or translucent part [0088] 6: semi-transparent film [0089] 8: first face [0090] 10: second face [0091] 12: protective layer [0092] 14: paint layer [0093] 16: primer undercoat [0094] 18: base layer [0095] 20: varnish layer [0096] 22: laser radiation [0097] 24: main shape in relief [0098] 25: light ray [0099] 26: secondary shape in relief [0100] 28: optical relief