WO2014207414A2

WO2014207414A2 - Indirect lighting device for a motor vehicle tail light

Info

Publication number: WO2014207414A2
Application number: PCT/FR2014/051676
Authority: WO
Inventors: Alain Buisson; Yves Fichot; Aurélie SORNIN
Original assignee: Automotive Lighting Rear Lamps France
Priority date: 2013-06-28
Filing date: 2014-06-30
Publication date: 2014-12-31
Also published as: CN105492824A; CN105492824B; EP3014172A2; FR3007821A1; WO2014207414A3; FR3007821B1; PL3014172T3; JP2016526768A; EP3014172B1

Abstract

The invention relates to a device for a lighting and/or signalling light of a vehicle, in particular for a tail light, characterised in that said device comprises, in a housing (1): at least one LED light source (3), attached to an opaque mounting (4, 9) comprising a lighting opening (5) intended for the passage of the light to be diffused indirectly toward the observer; a first opaque diffusing element (6) located upstream from the lighting opening and suitable for reflecting and diffusing the light from the light source toward the opening; a second translucent diffusing element (7) located downstream from the first diffusion element facing the lighting opening (5) and intended for transmitting and diffusing the light reflected and diffused by a first diffusing element; a third translucent diffusing element (8) located downstream from the second diffusing element (7) and suitable for transmitting and diffusing the light from the second diffusing element toward the outside of the light in question, said third diffusing element contributing to the shape of the light when turned on.

Description

INDIRECT LIGHTING DEVICE FOR MOTOR VEHICLE REAR LAMP

[01] The present invention relates to the field of lighting and signaling of vehicles, including motor vehicles. It relates more particularly to a device for signaling vehicles comprising indirect lighting whose light, emitted by at least one LED, is reflected by a scattering material which directs it to an output optic, itself diffusing, with several variants possible as needed.

[02] The regulations in force require, depending on the type of vehicle, different lighting or signaling lights. But, in addition to the volume of all fires, the performance and uniformity of illumination of individual fires thus grouped are major concerns.

[03] Already known in the prior art transparent auxiliary screens in which can propagate the light emitted by an auxiliary light source, these screens being intended to equip a fire, including rear, a motor vehicle. Local discontinuities provided in the screen material are foci of light scattering out of these screens (see French Patent Publication No. 2,868,506).

[04] German patent application DE 101 01 795 describes flashing lights, in particular front turn signals for motor vehicles, in which an auxiliary light source for position light illuminates an element arranged transversely in the space between the fire. main and frontal ice, and provides through it an illumination in the same direction as that of the main light.

[05] In the French patent application 01 00048, published under the number 2 819 040, is described an optical component or style for lighting or signaling of motor vehicles. This component is made of transparent material, inside which foci of light scattering are located only in predetermined locations to diffuse the light emitted by a source associated with the lighting or signaling device concerned. This component can be the mirror of a motor vehicle headlamp, or an insert placed in such a projector.

[06] German Patent Application DE 103 11 317 describes a vehicle lighting device comprising a light guide comprising diffusion located essentially at the focus of reflective surfaces which thus leave diffusing a homogeneous illumination.

[07] On the other hand, the present applicant has designed and described, in the French patent application filed on 30.01.2012 under No. 12,00270, a new device for lighting and / or vehicle signaling light. automobile, comprising one or more LEDs and incorporating a light guide, characterized in that it comprises, combined with said guide, a translucent screen, said translucent screen being provided with a graining and disposed between said guide and the visible face of the light or the set of lamps concerned, so as to provide a homogeneous color light function, while said translucent screen is provided with a graining on one or the other or both of its main faces capable of being traversed by the light emitted by the LEDs, and while the piece of translucent material is placed in front of said guide, preferably at a distance of about 5 to 20 mm from said guide.

[08] In these various applications and these various embodiments of light screens diffusing the light emitted by at least one LED, there may appear inhomogeneities in the scattered light, particularly at the level of the guides, including those which may be equipped with curtains or diffusers.

[09] It therefore seemed useful to seek to standardize the light rendering of such lights possibly including a light guide, or to hide any inhomogeneities.

[10] The present invention firstly relates to a device for lighting and / or signaling, including motor vehicle rear lights, as defined above and in the description which follows. The invention also relates to an optical unit comprising such a device, as well as the use of said device for lighting or signaling, including but not exclusively in the rear lights of motor vehicles.

[11] The present invention thus relates to a device for lighting and / or vehicle signaling, in particular for taillights, characterized in that it comprises in a housing:

at least one LED light source, fixed on an opaque support having an illumination opening intended for the passage of the light to be diffused indirectly towards the observer, a first opaque diffusing element situated upstream of the illumination opening and adapted to reflect and diffuse the light coming from the light source in the direction of the opening,

a second translucent diffusing element situated downstream of the first diffusing element at the right of the illumination opening and intended to transmit and diffuse the light reflected and diffused by the first diffusing element,

a third translucent diffusing element located downstream of the second diffusing element and adapted to transmit and diffuse light coming from the second diffusing element towards the outside of the fire concerned, said third diffusing element contributing to the geometry of the fire in the state alight.

[12] The implementation of three scattering elements in the path of the light before its perception by an observer makes it possible to better control the perceived homogeneity by attenuating the effect of point light sources induced by the light-emitting diode (s), in particular abbreviated LED or LED for English "electro luminescent diode" constituting the light source according to the invention. In addition, the fact that the three diffusing elements are not juxtaposed but distant from one another makes it possible to better exploit their diffusing effect. Moreover, it should be noted that each diffusing element offers at least two means of modulating the diffusion that it induces to know the nature of the material that constitutes it and / or the state of one of its outer surfaces.

[13] The lighting device according to the invention implements indirect lighting in that the light from the light source comes out of the lighting device after reflection on the surface of the first diffusing element. Thus the light source is carried by opaque support which prevents any direct output of the light outside the lighting device.

[14] According to a feature of the invention, in order to increase the amount of reflected light the first diffusing element is opalescent white in color. Such a color allows effective reflection of light.

[15] According to another characteristic, the reflection surface of the first diffusing element has an irregular surface state. By irregular surface condition it is to be understood that the reflection surface of the first diffusing element does not include a regular pattern such as mirrors or Fresnel lenses but an irregular random or pseudo random pattern. Thus, the irregular nature of the surface condition can be likened to a non-homogeneous character. This irregular state can for example be obtained by graining. Graining is here understood to mean the formation of discontinuities in and / or on the constituent material of the diffusing element concerned.

[16] Classically, the grained material can then be made:

- without adding or removing material, by appropriate treatment of all or part of the inner wall of the mold for making the element to be grained, and / or

by addition of reactive material capable of generating inclusions in the material used to produce the diffusing element or grained opaline screen, under the conditions of preparation thereof,

in both cases according to techniques known to those skilled in the art, which knows how to adapt the roughness obtained to the desired effect.

[17] According to another characteristic of the invention, the first diffusing element is made of a material loaded with particles of dimensions greater than or equal to one micron and / or comprising inclusions of dimensions greater than or equal to one micron. The material constituting the first diffusing element is then a non-homogeneous material such as an opaline material. Such an opaline-type material may for example be PMMA (poly methyl methacrylate) or PC (polycarbonate) to which are added materials selected from microbeads of opalescent material or a dispersible material, in particular to create inclusions such as micro bubbles by the injection and distribution of a gas, in particular C0 ₂ , to give a random character to the opalescence produced. The opaline material may be white or colored, especially to appear amber or super-light blue, by techniques known to those skilled in the art. It can thus make it possible to obtain a color in the lit state different from the color in the off state. It is also possible to use in the light source one or more LEDs that emit a colored light, for example red or amber.

[18] Preferably, the second and third scattering elements are translucent. This translucent state can be obtained in various ways, either by the state of one or the other or both of the outer surfaces of each diffusing element either by the nature of the material which constitutes it, or the combination of several of these three. means.

[19] According to a feature of the invention, the front surface and / or the rear surface of the second diffusing element has an irregular surface condition. This irregular state can be obtained in the same way as for the irregular state of the reflection surface of the first diffusing element. The terms front and rear are used in the context of the present invention in relation to the path of the light from the LED light source, the front face receiving light before the rear face. It is the same for the terms upstream and downstream.

[20] According to another characteristic of the invention, the second diffusing element is made of a material loaded with particles of dimensions greater than or equal to one micron and / or comprising inclusions of dimensions greater than or equal to one micron. Such a charged material may be a colored or unstained transparent material whose inclusions give it a translucent character. The material, also called matrix, may be PMMA (poly methyl methacrylate) or PC (polycarbonate).

[21] According to another characteristic of the invention, the front surface and / or the rear surface of the third diffusing element has an irregular surface condition. This irregular surface condition may be analogous to the possible irregular surface condition of the second diffusing element.

[22] According to another characteristic of the invention, the third diffusing element is made of a material loaded with particles of dimensions greater than or equal to one micron and / or comprising inclusions of dimensions greater than or equal to one micron. This translucent charged material may be as previously described for the second diffusing element.

[23] According to one embodiment of the invention the lighting device comprises a transparent and / or translucent indicator adapted to close the housing. Preferably the indicator ensures a waterproof closure.

[24] According to another embodiment, the third diffusing element is adapted to close the housing. Preferably, the third diffusing element ensures a watertight closure.

According to a variant of this embodiment, the third diffusing element has a smooth rear surface.

According to one characteristic of the invention, the lighting device comprises an opaque mask situated on the rear face or on the front face of a portion of the third diffusing element which is offset with respect to the illumination opening. and which carries the source of light. [27] According to a variant of this characteristic, the second diffusing element is doubled, preferably by overmolding, by the offset portion of the third diffusing element.

[28] According to another characteristic of the invention, the second diffusing element carries an opaque element which partially obscures it.

[29] Of course, the various features, variations and embodiments of the invention may be associated with each other in various combinations to the extent that they are not incompatible or exclusive of each other.

[30] Furthermore, various other features of the invention emerge from the attached description with reference to the drawings which illustrate non-limiting embodiments of a lighting device according to the invention.

- Fig. 1 is a diagrammatic representation in elevation of a horizontal section of a lighting device according to the invention,

- Fig. 2 is a schematic representation in elevation of a horizontal section of a variant of the lighting device according to the invention,

- Fig. 3 is a schematic representation in elevation of a horizontal section of another variant of the lighting device according to the invention,

It should be noted that in these figures the structural and / or functional elements common to the different variants may have the same references.

[31] As shown in FIG. 1 a lighting device according to the invention comprises in a housing 1 at least one LED light source comprising at least one printed circuit board or PCB 2 carrying at least one LED 3. The light source is fixed on a support opaque 4 having at least one lighting aperture 5. The lighting device then comprises a first diffusing element 6 adapted to reflect and diffuse the light in the direction of the illumination aperture 5.

[32] The lighting device comprises, at the opening a translucent screen forming the second diffusing element 7 adapted to be traversed by the light diffused by the first diffusing element 6 and to diffuse said light.

[33] The lighting device also comprises a third diffusing element 8 in turn contributes to the scattering of the light passing through it.

[34] Thus the combination of the three diffusing elements 6, 7, 8, the first working in reflection, the other two in transmission, thus produces the emission towards the outside, on the front face or front of the fire concerned, of homogenized lighting, the source of which is not or very little visible from the observer. The light is not perceived by the observer as the result of a juxtaposition of intense point sources but as coming from a single diffuse source without a hot spot, which reduces the dazzling of the observer when he is close to traffic light.

[35] According to the illustrated example, the front and rear faces of the third diffusing element 8 are provided with graining 11.

[36] Furthermore, in the present case, the rear face with respect to the PCB 2 carrying the LED 3 of the portion 10 of the element 8 is advantageously provided with an opaque element 9, which obscures the diffusing parts facing each other, therefore other than those dedicated to the third diffusing element 8, in the eyes of the observer. This occulting element can in practice be shaped and metallized to suit, and thus play a role of cache vis-à-vis the light rays other than those that the third scattering element receives and diffuses.

[37] For more homogeneity, a better rendering of the lighting and a good evacuation of the heat emitted by the LEDs, the PCB 2 support of the LEDs is separated from the plane of the part of the third diffusing element located outside the savings or opening aforesaid, while the entire PCB + LEDs is surrounded by a mask 9 having only one aperture chosen or adjustable to suit the LEDs.

[38] According to the illustrated example, the lighting device advantageously also comprises an opaque mask suitably located on the rear face or on the front face of a portion 10 of the third diffusing element projecting from the opening, the

PCB is then attached to this portion of the third scattering element.

[39] In the embodiment shown in FIG. 1, the material of the second diffusing element 7 is doubled, preferably by overmoulding, by said protruding portion of the third diffusing element 8.

[40] In practice, for a good rendering of the light intensity to the output of the fire housing concerned, the first diffusing element is made of opal white PC [polycarbonate].

[41] The second and third diffusing elements 7, 8 are preferably made of PMMA [polymethyl methacrylate] or PC [polycarbonate], with at least one irregular outer surface preferably grained, sandblasted or brushed. The material constituting the second and third diffusing elements can also be loaded with microscopic particles larger than one micron in order to increase the diffusing power of said elements. According to the exemplary embodiment illustrated in FIG. 1, the housing 1 is closed by a light or window 12.

[43] FIG. 2 shows another embodiment which differs from that of FIG. 1 in that the support and / or opaque mask 4, 9 is flat and applied against the free face of the third diffusing element 10 which is itself advantageously formed in overmolding with the second diffusing element 7;

[44] According to the embodiment shown in FIG. 3, the element 4 or 9 opaque is integrated into the fire in front of the second diffusing element 7 and thus releases its opposite surface on which is applied the third diffusing element 8 which can then constitute by itself the light 12 of the fire, of which the diffusion volume defined by the profile of the element 8 protrudes outwardly towards the fire.

[45] This embodiment has the advantage of providing a lighting and / or signaling light of reduced thickness. In practice, the maximum thickness represented by A in the figure can thus be between 20 mm and 30 mm. In addition, the X and Y dimensions of the space enclosed by the third diffusing element 8 can also be suitably varied, according to both aesthetic and functional choices that are easily applicable by those skilled in the art.

[46] In the embodiment illustrated in Fig.3, it is recommended to provide the graining only on the inner face, but not on the outer face of the third diffusing element which is then smooth.

[47] The device according to the invention may comprise other characteristics that can be taken separately or in any of their technically possible combinations, in particular:

- The mask 9 is constituted by a metalizable hubcap participating in the aesthetic appearance of the perimeter of the fire concerned.

a graining can be provided on the external face (rear) and / or on the internal face (front) of the third diffusing element,

- It is preferred to confer said graining to the inner face of the third element when it substitutes for the light of the housing.

[48] The device according to the invention is mainly intended to equip, with the appropriate power source and connectors, lighting systems forming lantern, brake light, raised brake light, flashing and / or possibly daytime running light front of motor vehicles.

Claims

1. Device for lighting and / or vehicle signaling, in particular for taillights, characterized in that it comprises in a housing (1):

at least one LED light source (3), fixed on an opaque support (4, 9) having a lighting opening (5) intended for the passage of the light to be diffused indirectly towards the observer,

a first opaque diffusing element (6) situated upstream of the illumination opening and adapted to reflect and diffuse the light coming from the light source in the direction of the opening,

a second translucent diffusing element (7) situated downstream of the first diffusing element at the right of the lighting aperture (5) and intended to transmit and diffuse the light reflected and diffused by the first diffusing element,

a third translucent diffusing element (8) located downstream of the second diffusing element (7) and adapted to transmit and diffuse light coming from the second diffusing element towards the outside of the fire concerned, said third diffusing element contributing to the geometry fire in the lit state.

2. Lighting device according to the preceding claim characterized in that the first diffusing element is white.

3. Lighting device according to one of the preceding claims characterized in that the reflection surface of the first diffusing element has an irregular surface condition.

4. Device according to one of the preceding claims characterized in that the first diffusing element is made of a material loaded particles greater than or equal to one micron and / or comprising inclusions of dimensions greater than or equal to one micron.

5. Lighting device according to one of the preceding claims characterized in that the front surface and / or the rear surface of the second element has an irregular surface condition.

6. Lighting device according to one of the preceding claims, characterized in that the second diffusing element is made of a material loaded with particles of dimensions greater than or equal to one micron and / or comprising inclusions of dimensions greater than or equal to one micron. .

7. Lighting device according to one of the preceding claims, characterized in that the front surface and / or the rear surface of the third element has an irregular surface condition.

8. Lighting device according to one of the preceding claims, characterized in that the third diffusing element is made of a material loaded with particles of dimensions greater than or equal to one micron and / or comprising inclusions of dimensions greater than or equal to one micron .

9. Lighting device according to one of the preceding claims, characterized in that it comprises a transparent and / or translucent indicator (12) adapted to close the housing.

10. Lighting device according to one of the preceding claims characterized in that the third diffusing element (8) is adapted to close the housing.

11. Lighting device according to claim 9 characterized in that the third diffusing element (8) has a smooth rear surface.

12. Lighting device according to one of the preceding claims, characterized in that it comprises an opaque mask (4, 9) located on the rear face or on the front face of a portion of the third diffusing element offset relative to to the lighting opening that carries the light source.

13. Lighting device according to claim 11, characterized in that the second diffusing element (7) is doubled, preferably by overmolding, by the offset portion of the third diffusing element (8).

14. Lighting device according to one of the preceding claims, characterized in that the second diffusing element carries an opaque element which partially obscures it.