Method for manufacturing a transparent vehicle part

Abstract

In this method for manufacturing a vehicle part, the following steps are implemented, applying a first varnish coat to a transparent part, applying a paint coat to the first varnish coat, applying a second varnish coat to the paint coat, and irradiating the paint coat and the second varnish coat in part with laser radiation.

Claims

1. A method for manufacturing a transparent external vehicle part, characterized in that it comprises the following successive steps: applying a first varnish coat, which is transparent to visible light, to a transparent part, applying a paint coat to the first varnish coat, applying a second varnish coat to the paint coat, and irradiating the paint coat and the second varnish coat in part with laser radiation so as to etch through the paint coat and the second varnish coat and expose a portion of the first varnish coat, wherein the first and second varnish coats are transparent to any laser radiation having a wavelength within the near infrared.

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

3. The method according to claim 2, wherein the plastic is one of polycarbonate, polypropylene, or poly(methyl methacrylate).

4. The method according to claim 1, wherein the laser radiation has a wavelength within the infrared.

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

6. The method according to claim 1, wherein the first and second varnish coats are made of a material that is capable of absorbing or reflecting ultraviolet radiation.

7. The method according to claim 1, wherein the first and second varnish coats are made of a same material.

8. The method according to claim 1, wherein the paint coat comprises a primer undercoat.

9. The method according to claim 1, wherein the vehicle part is polished after the irradiation step.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) 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:

(2) FIG. 1 is a sectional view of a first step in the implementation of a manufacturing method according to the invention, and

(3) FIG. 2 is a sectional view of a second step in the implementation of a manufacturing method according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(4) FIG. 1 shows a first step of a method for manufacturing a vehicle part 2.

(5) The vehicle part 2 comprises a transparent part 4 that is intended to protect a light source (not shown). The term “transparent” 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 transparent part from any other plastic having this characteristic, such as polypropylene (PP) or poly(methyl methacrylate) (PMMA). The transparent part is produced by molding. Since such a method is known, we will not go into further detail about it in the following.

(6) The vehicle part 2 comprises a first varnish coat 6 that is deposited onto an external surface of the transparent part 4. The term “external surface” is understood to mean a surface of the transparent part 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 first varnish coat 6 protects the transparent part 4 from any ultraviolet radiation to which it may be exposed, particularly from the sun. In addition, the first varnish coat 6 makes it possible to mechanically protect the transparent part, particularly to prevent it from being scratched or deformed by external stresses.

(7) The vehicle part 2 comprises a paint coat 7 that is deposited onto the external surface of the transparent part 4 on top of the first varnish coat 6. Here, the paint coat 7 comprises a primer undercoat 8 onto which a base coat 10 is deposited. The base coat 10 makes it possible to color the external appearance of the vehicle part 2. The primer undercoat 8 improves the opacity of the paint coat 7 and improves the adhesion of the base coat 10 to the transparent part 4.

(8) The vehicle part 2 comprises a second varnish coat 12, which is deposited onto the external surface of the transparent part 4 on top of the paint coat 7. The second varnish coat 12 makes it possible to protect the transparent part 4 and the paint coat 7 from any ultraviolet radiation to which they may be exposed. Here, the first and second varnish coats are made of the same material, but a provision can be made to use two different varnishes to produce the two coats 6, 12.

(9) According to the first step of the method for manufacturing the vehicle part 2, the first varnish coat 6, then the paint coat 7, and then the second varnish coat 12 is deposited onto the transparent part 4.

(10) FIG. 2 shows a second step of the method for manufacturing the vehicle part 2. In this step, a portion of the vehicle part 2 is irradiated using laser radiation 14 so as to etch the paint coat 7 and the second varnish coat 12. This etching is carried out throughout the thickness of the paint coat 7 and the second varnish coat 12. This operation is commonly referred to as “laser-etching.” In the context of the invention, the laser radiation 14 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 14 is in the near infrared, i.e., between 700 and 2,000 nm. In this case—and if the first 6 and second 12 varnish coats are transparent to laser radiation 14—the latter range has the advantage of not etching the varnish coats. This avoids the risk of damaging the varnish coats.

(11) 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 second varnish coat 12. It is controlled in such a way that the second varnish coat 12 and the paint coat 7 are irradiated and hence eliminated in the pattern and throughout their thickness, but not the first varnish coat 6, which protects the transparent part from ultraviolet radiation in the regions of the pattern that have been etched. Even if the second varnish coat 12 is made of a material that is transparent to laser radiation 14, the irradiation of the underlying paint coat 7 makes it possible to eliminate the second varnish coat 12 in the pattern.

(12) After irradiation, the surface of the vehicle part 2 has two levels.

(13) In the region of the predefined pattern, the transparent part 4 is coated only with the first varnish coat 6. In this region, visible light can be transmitted from the light source to the outside environment, and vice versa.

(14) Outside the region of the predefined pattern, the transparent part 4 is coated with the first varnish coat 6, the paint coat 7, and the second varnish coat 12. 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 coat 7. In particular, the protection of the transparent part 4 from ultraviolet radiation to which it may be exposed is ensured by the second varnish coat 12.

(15) 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 aesthetics 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 aesthetics of the vehicle part 2 and its tactile surface quality.

(16) The invention is not limited to the embodiments described here, and other embodiments will become clearly apparent to a person skilled in the art.

(17) The light source can be part of an optical block of low and high beams of the vehicle, of an optical block of turn signals of the vehicle, or of an optical block of decorative lights.

(18) 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

(19) 2: vehicle part

(20) 4: transparent part

(21) 6: first varnish coat

(22) 7: paint coat

(23) 8: primer undercoat

(24) 10: base coat

(25) 12: second varnish coat

(26) 14: laser radiation