EP3715706A1

EP3715706A1 - Automotive lighting device and method for manufacturing an automotive lighting device

Info

Publication number: EP3715706A1
Application number: EP19166387.1A
Authority: EP
Inventors: Antonio CAMACHO; Juan-Jesus LOPEZ; Daniel Teba; Alberto Lara
Original assignee: Valeo Iluminacion SA
Current assignee: Valeo Iluminacion SA
Priority date: 2019-03-29
Filing date: 2019-03-29
Publication date: 2020-09-30

Abstract

The invention provides an automotive lighting device (1) comprising an optic reflector (2) which comprises a first portion (3) and a second portion (4). The first portion (3) and the second portion (4) are joined by a foldable slim zone (5). The foldable slim zone (5) is configured to be bended to allow the second portion (4) be coupled to the first portion (3) to form an optic reflector (2). The invention also provides a manufacturing method for this optic reflector (2).

Description

TECHNICAL FIELD

The present invention belongs to the field of lamps for automotive vehicles, and more specifically, to the design and manufacturing of optic reflectors.

STATE OF THE ART

Current headlamps comprise metallized reflectors, which are in charge of projecting the light emitted by the light sources.
To do so, these parts are usually manufactured in plastic, and then covered by metal particles, in a metallization process. However, when a reflector design only allows a very tight window to place the reflective surface, the metallization particles do not reach the whole reflector surface, since there are zones which are not easily accessible under vacuum conditions.
To solve this problem, one of the possibilities is increasing reflector width and/or height, so that it is easier for metal particles to reach the farthest zones. However, this implies a design change, and sometimes it is not possible to change the size of the reflector, since it would affect to other elements which are involve in the headlamp design.
Another solution would be to introduce holes on the reflector sides to allow accessibility of metallization vapours to the reflective walls. However, these holes would worsen the luminous behaviour of the lighting reflector.
An alternative solution for this problem is therefore sought

DESCRIPTION OF THE INVENTION

The invention provides a solution for improving the manufacturing of a reflector by the provision of an automotive lighting device according to claim 1 and a method for manufacturing an automotive lighting device according to claim 11. Preferred embodiments of the invention are defined in dependent claims.
Unless otherwise defined, all terms (including technical and scientific terms) used herein are to be interpreted as is customary in the art. It will be further understood that terms in common usage should also be interpreted as is customary in the relevant art and not in an idealised or overly formal sense unless expressly so defined herein.
In this text, the term "comprises" and its derivations (such as "comprising", etc.) should not be understood in an excluding sense, that is, these terms should not be interpreted as excluding the possibility that what is described and defined may include further elements, steps, etc.
In a first inventive aspect, the invention provides an automotive lighting device comprising an optic reflector which comprises a first portion and a second portion, wherein

the first portion and the second portion are joined by a foldable slim zone;
the foldable slim zone is configured to be bended to allow the second portion be coupled to the first portion to form an optic reflector.

This solution avoid any photometry problems caused by holes in the reflector or by the joint line generated when demoulding a reflector with tight demoulding angles, and it further solves the metallization problems, since the shadow generated by the second portion is eliminated: the reflector may be metallized with the second portion being open and then the second portion may be closed to form the final reflector. This optic reflector may be manufactured in a single piece, avoiding problems associated to using several moulds.
In some particular embodiments, the automotive lighting device comprises more than one foldable slim zones, and further comprises a reinforce element between the slim zones.
Sometimes the plastic material flowability does not allow a very slim foldable zone, so a single slim zone may not be enough for a 180º folding operation. In these cases, more than one slim zones may be provided, to perform a sequential folding and get the second portion be closed over the first portion.
In some particular embodiments, the optic reflector is made of plastic.
Plastic is the common material for performing these elements, being a cheap one and accepting a further metallization process.
In some particular embodiments, the first portion comprises a first fitting element and the second portion comprises a second fitting element, and the first fitting element and the second fitting element are intended to be coupled.
These fitting elements improve the connection between the first and second portions, and achieves a more reliable assembly.
In some particular embodiments, the first fitting element and the second fitting element form a clipping joint. In other embodiments, the first fitting element and the second fitting element form a snap fit joint. In different embodiments, the first fitting element and the second fitting element form a pressure joint.
These types of joints are suitable for achieving a compact and reliable assembly, with a single step in the manufacturing assembly line.
In some particular embodiments, the automotive lighting device further comprises solid-state light sources.
The term "solid state" refers to light emitted by solid-state electroluminescence, which uses semiconductors to convert electricity into light. Compared to incandescent lighting, solid state lighting creates visible light with reduced heat generation and less energy dissipation. The typically small mass of a solid-state electronic lighting device provides for greater resistance to shock and vibration compared to brittle glass tubes/bulbs and long, thin filament wires. They also eliminate filament evaporation, potentially increasing the life span of the illumination device. Some examples of these types of lighting comprise semiconductor light-emitting diodes (LEDs), organic light-emitting diodes (OLED), or polymer light-emitting diodes (PLED) as sources of illumination rather than electrical filaments, plasma or gas.
In some particular embodiments, the light sources are mounted in a printed circuit board.
The automotive lighting device may be specially designed for LEDs, wherein these LEDs may be mounted in a printed circuit board and emit light towards the reflector.
In some particular embodiments, the optic reflector comprises more than one reflective cavities.
LEDs arrangements involve the use of different cavities in the reflector, so that each cavity reflects the light emitted by one of the LEDs.
In a further inventive aspect, the invention provides a method for manufacturing an automotive lighting device according to the first inventive aspect, the method comprising the steps of

designing a mould with a first portion of the optic reflector and a second portion of the optic reflector joined by the foldable slim zone, wherein the foldable slim zone of the mould is thick enough for a plastic material to flow through
injecting a plastic material in the mould to form the optic reflector
unmould the optic reflector;
perform a metallization of the optic reflector; and
fold the foldable slim zone to mount the optic reflector.

This method is advantageous since it provides an easy and reliable way of obtaining a lighting device with a convenient metallization without substantially altering the final shape of the optic reflector.
In some particular embodiments, the method further comprises the step of calculating the number of foldable slim zones depending on the flowability of the plastic material.
Depending on the flowability of the plastic material used and the requirements of the reflector, more than one foldable slim zone may be needed.

BRIEF DESCRIPTION OF THE DRAWINGS

To complete the description and in order to provide for a better understanding of the invention, a set of drawings is provided. Said drawings form an integral part of the description and illustrate an embodiment of the invention, which should not be interpreted as restricting the scope of the invention, but just as an example of how the invention can be carried out. The drawings comprise the following figures:

Figure 1 shows a particular embodiment of a support element used in an automotive lighting device according to the invention.
Figure 2 shows a schematic lateral view of an automotive lighting device according to the invention.
Figure 3 shows some steps of a manufacturing method for an automotive lighting device according to the invention.
Figure 4 shows a lighting device according to a particular embodiment of the invention installed in an automotive vehicle.

DETAILED DESCRIPTION OF THE INVENTION

The example embodiments are described in sufficient detail to enable those of ordinary skill in the art to embody and implement the systems and processes herein described. It is important to understand that embodiments can be provided in many alternate forms and should not be construed as limited to the examples set forth herein.
Accordingly, while embodiment can be modified in various ways and take on various alternative forms, specific embodiments thereof are shown in the drawings and described in detail below as examples. There is no intent to limit to the particular forms disclosed. On the contrary, all modifications, equivalents, and alternatives falling within the scope of the appended claims should be included. Elements of the example embodiments are consistently denoted by the same reference numerals throughout the drawings and detailed description where appropriate.
Figure 1 shows a particular embodiment of an optic reflector 2 used in an automotive lighting device according to the invention, before being finished.
This optic reflector 2 comprises a first portion 3 and a second portion 4 joined by a foldable slim zone 5. This foldable slim zone 5 is configured to be bended to allow the second portion 4 be coupled to the first portion 3. To achieve a reliable joint, the first portion 3 comprises a first fitting element 7 and the second portion 4 comprises a second fitting element 8. This bending is not shown in this figure yet.
The optic reflector 2 is manufactured by mould injection of a plastic material. The mould follows the shape shown in figure 1. Before injecting the plastic material, the size of the foldable slim zone is carefully calculated by mould flow simulations, so that this part of the mould is thick enough for a plastic material to flow through.
Figure 2 shows a detail of this bending portion. The calculations mentioned before provide the number of foldable slim zones which are necessary to guarantee a feasible manufacturing process and a feasible bending of the second portion over the first portion. For example, this figure 2 shows two foldable slim zones 5, 5' between first and second portions 3, 4, with a reinforce element 6 between the slim zones 5, 5'. This reinforce element 6 divides the slim zone for a better behaviour of the plastic material in the manufacturing process.
After the mould has been designed with the optimal shape in the foldable slim zone, the plastic material is injected in the mould to form the optic reflector. Once the injection process is finished, the optic reflector is unmoulded, thus obtaining an element as the one of figure 1. Then, the optic reflector is metallized, taking advantage of the absence of shadows provided by the open second portion 4. As a consequence, the metallization particles may reach the whole inner surface of the reflector 2 and then achieve a successful metallization process.
Finally, after the metallization process has been finished, the second portion 4 is bended over the first portion 3 and adjusted by some fitting elements.
Figure 3 shows a finished optic reflector 2 according to the invention, once the second portion 4 has been bended over the first portion 3 by means of folding over the foldable slim portion 5.
As aforementioned, to achieve a reliable joint, the first portion 3 comprises a first fitting element 7 and the second portion 4 comprises a second fitting element 8. Both first and second fitting elements 7, 8 provide a clipping joint which adjusts the second portion 4 to form the final structure of the optical reflector 2.
Figure 4 shows a lighting device 1 according to the invention installed in an automotive vehicle 100. This automotive lighting device 1 comprises a plurality of LEDs 20 and a housing which encloses an optical reflector 2 specially adapted for LEDs, with a printed circuit board to receive the LEDs and a plurality of cavities to project the light emitted by each one of them.

Claims

Automotive lighting device (1) comprising an optic reflector (2) which comprises a first portion (3) and a second portion (4), wherein
the first portion (3) and the second portion (4) are joined by a foldable slim zone (5);

the foldable slim zone (5) is configured to be bended to allow the second portion (4) be coupled to the first portion (3) to form an optic reflector (2).
Automotive lighting device (1) according to claim 1, comprising more than one foldable slim zones (5, 5'), and further comprises a reinforce element (6) between the slim zones (5, 5').
Automotive lighting device (1) according to any of the preceding claims, wherein the optic reflector (2) is made of plastic.
Automotive lighting device (1) according to any of the preceding claims, wherein the first portion (3) comprises a first fitting element (7) and the second portion (4) comprises a second fitting element (8), and the first fitting element (7) and the second fitting element (8) are intended to be coupled.
Automotive lighting device (1) according to claim 4, wherein the first fitting element (7) and the second fitting element (8) form a clipping joint.
Automotive lighting device (1) according to claim 4, wherein the first fitting element (7) and the second fitting element (8) form a snap fit joint.
Automotive lighting device (1) according to claim 4, wherein the first fitting element (7) and the second fitting element (8) form a pressure joint.
Automotive lighting device (1) according to any of the preceding claims, further comprising solid-state light sources (20).
Automotive lighting device (1) according to claim 8, wherein the light sources (20) are mounted in a printed circuit board.
Automotive lighting device (1) according to any of claims 8 or 9, wherein the optic reflector comprises more than one reflective cavities.
Method for manufacturing an automotive lighting device according to any of the preceding claims, the method comprising the steps of
designing a mould (50) with a first portion of the optic reflector and a second portion of the optic reflector joined by the foldable slim zone, wherein the foldable slim zone of the mould is thick enough for a plastic material to flow through

injecting a plastic material in the mould to form the optic reflector (2);

unmould the optic reflector (2);

perform a metallization of the optic reflector (2); and

fold the foldable slim zone (5) to mount the optic reflector.
Method according to claim 11, further comprising the step of calculating the number of foldable slim zones depending on the flowability of the plastic material.