LUMINOUS DEVICE COMPRISING AT LEAST TWO LASER-WELDED PORTIONS

Abstract

The present invention relates to a motor vehicle luminous device including at least one first portion that is transparent to at least one laser beam, the portion having at least one first polymer material, and at least one second portion that absorbs the laser beam and is transparent to at least some of the visible spectrum, including at least one second polymer material, the second portion being laser welded to the first portion.

Claims

1. Motor vehicle luminous device comprising: at least one first portion that is transparent to at least one laser beam, said portion comprising at least one first polymer material, and at least one second portionthat absorbs said laser beam and that is transparent to at least some of the visible spectrum, comprising at least one second polymer material, said second portion being laser welded to said first portion.

2. Motor vehicle luminous device according to claim 1, the first polymer material comprises at least one organic polymer chosen from polymethyl methacrylate (PMMA), polycarbonate (PC), the polymer acrylonitrile butadiene styrene (ABS), polybutylene terephthalate (PBT), acrylonitrile styrene acrylate (ASA), polyethylene terephthalate (PET) and one of the blends thereof

3. Motor vehicle luminous device according to Claim 2, wherein the second polymer material comprises at least one organic polymer chosen from polymethyl methacrylate (PMMA), polycarbonate (PC), the polymer acrylonitrile butadiene styrene (ABS), polybutylene terephthalate (PBT), acrylonitrile styrene acrylate (ASA), polyethylene terephthalate (PET) and one of the blends thereof.

4. Motor vehicle luminous device according to any ons claim 3, wherein the second portion comprises at least one second filler that absorbs said laser beam.

5. Motor vehicle luminous device according to claim 4, wherein the first portion is able to absorb at least some of the visible spectrum.

6. Motor vehicle luminous device according to claim 5, wherein the first portion comprises at least one first filler that absorbs at least some of the visible spectrum.

7. Motor vehicle luminous device according claim 1, wherein the first portion is a housing forming a chamber able to accommodate at least one light source and/or at least one luminous module.

8. Motor vehicle luminous device according to any one claim 7, wherein the second portion is a closing outer lens.

9. Process for manufacturing a luminous device according to claim 8, wherein the device comprises the following steps: i. bringing the first portion and the second portion into contact, ii. then irradiating said second portion through said first portion with at least said laser beam, in order to weld said second portion to said first portion.

10. Manufacturing process according to claim 9, wherein said laser beam irradiates said second portion at a wavelength ranging from 800 nm to 1050 nm.

11. Manufacturing process according to claim 10, wherein the process furthermore comprises the following step, after step i: i. irradiating said second portion through said first portion with at least one light beam that is different from the laser beam.

12. Manufacturing process according to claim 11, wherein the light beam irradiates said second portion at a wavelength ranging from 350 nm to 1000 nm.

13. Manufacturing process according to any one of claim 12, wherein the laser beam irradiates the second portion at a temperature above the melting point of the second polymer material.

14. Motor vehicle luminous device according to claim 1, wherein the second polymer material comprises at least one organic polymer chosen from polymethyl methacrylate (PMMA), polycarbonate (PC), the polymer acrylonitrile butadiene styrene (ABS), polybutylene terephthalate (PBT), acrylonitrile styrene acrylate (ASA), polyethylene terephthalate (PET) and one of the blends thereof.

15. Motor vehicle luminous device according to claim 1, wherein the second portion comprises at least one second filler that absorbs said laser beam.

16. Motor vehicle luminous device according to claim 1, wherein the first portion is able to absorb at least some of the visible spectrum.

17. Motor vehicle luminous device according to claim 16, wherein the first portion comprises at least one first filler that absorbs at least some of the visible spectrum.

18. Motor vehicle luminous device according claim 6, wherein the first portion is a housing forming a chamber able to accommodate at least one light source and/or at least one luminous module.

19. Motor vehicle luminous device according to claim 1, wherein the second portion is a closing outer lens.

20. Process for manufacturing a luminous device according to claim 8, wherein the device comprises the following steps: i. bringing the first portion and the second portion into contact, ii. then irradiating said second portion through said first portion with at least said laser beam, in order to weld said second portion to said first portion.

Description

[0115] Other features and advantages of the present invention will become apparent in light of the description of nonlimiting examples of luminous modules according to the invention, which are given with reference to the figures.

[0116] FIG. 1 shows a schematic simplified view of a process for manufacturing a luminous module according to the invention.

[0117] FIG. 2 shows a schematic simplified view of a luminous device according to the invention.

[0118] For the sake of clarity, only those components that are essential to the comprehension of the invention have been shown, schematically and not to scale.

[0119] FIG. 1 shows a schematic simplified view of a process for manufacturing a luminous module according to the invention. A first portion 2 comprises a first contact surface 4 and a second portion 6 comprises a second contact surface 8. According to the process of the invention, the first portion 2 is brought into direct physical contact with the second portion 6, and, in particular, the first contact surface 4 is brought into direct physical contact with the second contact surface 8, forming the contact zone 9. A welding device 10 emits at least one laser beam 12 and at least one light beam 14. The first portion 2 is transparent to the laser beam 12 and to the light beam 14, and the second portion 6 absorbs the laser beam 12 and the light beam 14. Thus, the laser beam 12 irradiates the second portion 6 level with the second contact surface 8 through the first portion 2, allowing the second polymer material of the second portion 6 to be melted, in particular level with the second contact surface 8. The first polymer material and the second polymer material blend level with the contact zone 9, thereby allowing the two portions 2 and 6 to be welded with each other. Concomitantly, the light beam 14 irradiates the second portion 6 level with the second contact surface 8 through the first portion 2. This allows the second polymer material of the second portion 6 to be softened and the second contact surface 8 to better conform with the first contact surface 4, allowing a high-quality weld to be obtained. The irradiation by the light beam 14 furthermore allows the first and second polymer materials to reach their melting point more rapidly.

[0120] FIG. 2 shows a schematic simplified view of a luminous device according to the invention. The luminous device 20 comprises a casing 22 that accommodates a luminous module 24, and a closing outer lens 26 allowing the casing 22 to be closed. The casing 22 and the closing outer lens 26 have been welded to each other by the process of the invention such as described in FIG. 1, the casing 22 being formed by the first portion 2 and the closing outer lens 26 being formed by the second portion 6. In this luminous device, the casing 22 is black, and therefore absorbs visible light, and transparent to the laser beam 12 and to the light beam 14. The closing outer lens 26 absorbs the laser beam 12 and the light beam 14.

EXAMPLE

Step i

[0121] In this exemplary embodiment, the polymer material used for the first portion of the luminous device is the transparent polymethyl methacrylate of black color sold by Altuglas International (Arkema group) under the reference Plexiglas V825T black 58015. This first polymer material: [0122] is transparent to the laser at a wavelength of 980 nm, [0123] possesses a melting point of 230° C., and [0124] is of black color.

[0125] The polymer material used for the second portion of the luminous device is the polymethyl methacrylate sold by Evonik Röhm GmbH under the reference Plexiglas Heatresist hw55. This second polymer material: [0126] absorbs the laser at a wavelength of 980 nm, [0127] is transparent to visible light, and [0128] possesses a melting point of 230° C.

[0129] In step i of the process, the first portion is brought into contact with the second portion; in particular, the first contact surface of the first portion makes direct physical contact with the second contact surface of the second portion, and the weld will be produced level with these two contact surfaces. A compressing step is carried out in order to guarantee the contact between the two contact surfaces level with the zone to be welded.

Steps ii and iii

[0130] After step i, step ii and step iii are carried out concomitantly and comprise irradiating the second portion through the first portion with a laser beam and a light beam.

[0131] The laser beam irradiates the second portion through the first portion at a wavelength of 980 nm and with a power of 120 W, and thus allows the second polymer material to be melted, the temperature level with the second contact surface being comprised between 200° C. and 280° C. The radius of the laser beam is 4 mm, and the welding speed is about 80 mm/s. The second polymer material melts and blends with the first polymer material level with the contact zone.

[0132] Concomitantly, the light beam is generated by a halogen lamp that emits in the infrared, and that may also emit in the visible. The power of this halogen lamp is 1200 W and allows the second portion to be softened level with the second contact surface, at a temperature comprised between 80° C. and 90° C., in order to ensure a good conformity of the contact zone. The radius of the light beam is larger than that of the laser beam, so that the area irradiated by the radiation of the laser beam is contained within the area irradiated by the light beam.

Step iv

[0133] After steps ii and iii have been carried out, a cooling step iv is carried out at a temperature of 25° C.

[0134] The compression implemented in step i is maintained during steps ii, iii and iv.

[0135] The luminous device 20 such as shown in FIG. 2 comprising a casing 22 by way of first portion and a closing outer lens 26 by way of second portion is obtained.