Illumination – Supported by vehicle structure – Light modifier
Reexamination Certificate
1998-07-21
2001-01-16
Spyrou, Cassandra (Department: 2872)
Illumination
Supported by vehicle structure
Light modifier
C362S516000, C362S517000, C362S518000, C362S521000, C362S522000, C362S297000, C362S346000
Reexamination Certificate
active
06174079
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to headlights for motor vehicles.
BACKGROUND OF THE INVENTION
It is known, from French patent specification FR 2 514 105 of the Company Valeo Vision, to provide a headlight which a light guide consists of a single transparent barrel arranged horizontally and transversely to the direction of emission, with the front of the barrel having a vertical outlet face for emitting light, and the rear of the barrel including a set of cut-outs of limited height defining a series of oblique reflective facets. These facets are disposed in an optical cooperating relationship with lenses having an axis parallel to the emission direction, so that the lenses project images corresponding to the facets in that direction.
Such a headlight, however, have the disadvantage that it is not possible to control the quantity of light flux arriving at each of the facets of the single optical barrel, because of the multiple reflections of the light rays within the latter. In this regard, because of the uncontrollable multiple reflections of the light rays within the barrel, it can happen that one or more facets of the barrel are very weakly illuminated. A consequence of this is that the quality of the final light beam is altered.
In addition, in such a headlight, no mounting means is provided for ensuring accurate positioning of the oblique reflective facets and of the output face of the light guide with respect to the lenses, such that the latter will project, in the emission direction, images corresponding to the facets at a predetermined position, despite the dispersions of light within the thickness of the transparent barrel. In addition, no means is provided for ensuring accurate positioning of the input face of the light guide with respect to the light source itself.
DISCUSSION OF THE INVENTION
In order to overcome the above mentioned drawbacks, the present invention is directed to a lighting module in which conduction of the light flux between the real light source and each facet of the light guide is individualized, in such a way that the illumination of the facets can be controlled, and the desired final light beam obtained; and in which a system is provided for mounting the light guide in such a way as to ensure accurate positioning of the facets and output face of these elements in relation to the dioptric elements, so that the latter will project, in the emission direction, images corresponding to the well-positioned facets in the light beam, as well as good positioning of the input face of the light guide with respect to the light source.
According to one aspect of the invention, a lighting module for a motor vehicle, comprising a real light source, means for concentrating the light radiation from the source on the end of a light guide having a plurality of oblique reflective facets cooperating with a plurality of homologous dioptric elements which are on an axis parallel to the direction of emission of light, is characterised in that the light guide comprises a plurality of transparent strips, juxtaposed in a stack and extending along the longitudinal axis of the light guide, each transparent strip being formed, at least at its end furthest from the real light source, with an oblique reflective facet, and in that the lighting module further includes a reference member for mounting the light guide therein, the reference member comprising a horizontal, generally flat, first portion defining a horizontal reference plane, together with a vertical, generally flat, second portion extending along the longitudinal axis of the light guide and defining a vertical reference plane, the stack of juxtaposed transparent strips of the light guide being mounted in abutment against the first and second portions of the reference member, in a predetermined position along the longitudinal axis of the light guide, so that their reflective flat facets cooperate optically with the dioptric elements, whereby the images of the facets projected by the latter in the emission direction are positioned in a predetermined way.
Thus, the invention has the advantage that the transparent strips constituting the light guide are in engagement in two horizontal and vertical reference planes defined by the flat first and second portions of the reference member. This avoids the optical problems associated with manufacturing tolerances in the transparent strips, because the reflective facets of the strips are positioned in a predetermined way with reference to the horizontal reference plane, and their output faces are likewise positioned in a predetermined way with reference to the vertical plane.
According to a preferred feature of the invention, the horizontal first portion of the reference member is an upper portion against which at least part of the upper surface of the light guide bears, and the vertical second portion of the reference member is a cut-out front portion against which the output faces, for emission of light, of the transparent strips of the light guide, being front faces of the strips, bear.
According to another preferred feature of the invention, the module further includes a retaining member fixed on the said reference member and in engagement against the rear and lower faces of the light guide, so as to maintain the transparent strips by compression in engagement against the first and second portions of the reference member. In this embodiment, the module preferably also includes compressible flexible elements interposed operatively between the rear face of the light guide and the retaining member. Thus, in a module according to the invention in this preferred form, the transparent strips are held in compression in two directions transverse to the longitudinal axis of the light guide, namely the vertical direction and the horizontal direction. There is no additional retaining component in the direction of the longitudinal axis of the light guide, because the compressive forces and friction forces between the faces of the various transparent strips of the light guide are enough to maintain these strips immobile in that direction.
Preferably, the module includes an elastic pressure element between the light guide and the first portion of the reference member.
According to a further preferred feature of the invention, the reference member includes at one end a frame for mounting therein an elliptical reflector carrying the real light source, so that the second focus of the said elliptical reflector is situated at the end of the uppermost, and shortest, transparent strip of the light guide, which is in direct engagement against the said first portion of the reference member.
According to yet another preferred feature of the invention, the horizontal first portion of the reference member comprises a flat upper part and a flat lower part, the said upper and lower parts being in horizontal planes parallel to each other and joined together through a step, the horizontal upper part having an oblique terminal edge, and the first portion having a locating element for positioning, with respect to the longitudinal axis of the light guide, the transparent strip that is directly in engagement against the upper part of the reference member.
Preferably according to the invention, masks are provided for producing a cut-off beam, the masks being disposed in the path of some elementary beams from at least some of the reflective facets, between the front face of the appropriate transparent strips and the associated dioptric elements, the masks being fixed to a mounting member at the front of the module, the mounting member being fixed on the reference member in a predetermined position with respect to the reference member, the mounting member including means for mounting the dioptric elements in the mounting member.
Thus the invention affords the advantage, due to the mounting member at the front or output side of the module, that accurate positioning of the dioptric elements (for example Fresnel lenses) and masks can be ensured with respect to the front or output faces of the t
Boutsikaris Leo
Morgan & Finnegan L.L.P.
Spyrou Cassandra
Valeo Vision
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