Patent Description:
The term automotive lighting and/or signaling device is used here in a very broad sense to comprise an automotive light, either rear or front, the latter also named a headlight or headlamp.

As is known, an automotive light serves to provide a signal or make the roadbed visible to the driver. In other words, the automotive light is a device intended to provide at least one lighting and/or signaling function of the vehicle. Lighting and/or signaling functions of the vehicle, for example include the position light, the turn signal, the brake light, the rear fog lamp, the reversing light, the dipped beam light, the high beam light, the daytime running light, and further similar lights typical of automotive lights. The device may also perform a merely aesthetical function, such as lighting devices that show logos and the like, which may be located both outside and inside the vehicle.

The present invention is particularly applied to lighting and/or signaling devices that use at least one LED light source that emits a light beam which is channeled in a light guide, through an inlet wall, called "incoupling", of said light guide. Subsequently, the light beam is reflected into the light guide and extracted through a front wall by means of specific extractors arranged along a rear wall called "outcoupling", opposite to said front wall.

It is fundamental there be no uneven concentrations and/or overlapping of light rays (i.e., spots) on the rear wall because in this case, said spots would also be repeated on the front wall, therefore being visible from the outside.

Indeed, the end user requires a uniform and homogenous distribution of the light beams, brightness being equal, possibly devoid of any spots.

Spots substantially are created from the overlapping and/or concentration of several light rays reflected into the light guide which tend to concentrate in certain areas of the outcoupling. The overlapping is due to that fact that separate light rays tend to overlap and/or concentrate in inhomogeneous manner in certain areas of the outcoupling due to the successive reflections inside the light guide.

The phenomenon is felt even more when the light guide has an overall reduced thickness and a particularly extensive rear wall, i.e., an outcoupling, such as, for example what occurs in the case of long and thin light guide plates or bars. Devices with such light guides are known from <CIT> and <CIT>.

It is the object of the present invention to provide a lighting and/or signaling device obtained with a rigid union technique of the internal components inside the container body, which overcomes the limitations of the techniques described in relation to an assembly of conventional type.

Such a need is met by an automotive lighting and/or signaling device according to claim <NUM>.

Other embodiments of the present invention are described in the dependent claims.

Further features and advantages of the present invention will be more comprehensible from the following description of preferred and non-limiting embodiments thereof, in which:.

The elements or parts of elements common to the embodiments described below will be indicated using the same numerals.

With reference to the aforesaid drawings, a lighting and/or signaling device, such as an automotive light, to which the following disclosure refers without however losing in generality, is indicated as a whole by <NUM>.

As mentioned above, the expression "lighting and/or signaling device" may indifferently mean either an automotive rear light or an automotive front light, the latter also known as headlight or headlamp, comprising a light external to the vehicle having a lighting and/or signaling function, such as, for example, a position light, which may be a front position light, a taillight, a side marker, a turn signal, a brake light, a rear fog lamp, a high beam light, a dipped beam light, and the like.

Thus, as better described below, the device in its signaling function may comprise the possibility of sending light signals, logos, but also words and lit messages of any kind. Thus, the device may perform a merely aesthetical function, such as lighting devices that show logos and the like, which may be arranged both outside and inside the vehicle.

The lighting and/or signaling device <NUM> comprises a container body or hollow housing <NUM>, usually made of polymeric material, such as, for example acrylonitrile butadiene styrene, or ABS, which conventionally allows fixing the lighting and/or signaling device <NUM> to the related vehicle or to any type of support.

For the purposes of the present invention, the container body or housing <NUM> may have any shape, size or position: for example, the container body <NUM> may also not be directly connected to the bodywork or other external fixings of the associable vehicle.

The container body <NUM> delimits a containment seat <NUM> which accommodates a plurality of components of said lighting and/or signaling device.

The containment seat <NUM> in particular accommodates at least one light source <NUM> arranged and supported inside said containment seat <NUM>. The at least one light source <NUM> preferably comprises LED or mini LED light sources adapted to emit a light beam comprising a plurality of light rays <NUM> which extend along a main optical propagation axis X-X.

For example, a lenticular body <NUM> may be placed at least partially to close the container body <NUM> so as to close said containment seat <NUM> which accommodates the light source <NUM>.

For the purposes of the present invention, the lenticular body <NUM> is external to the lighting and/or signaling device <NUM> so as to define at least one outer wall of the lighting and/or signaling device directly subject to the atmosphere, thus integrating with the line of the car, when the container body <NUM> is firmly recessed in the enclosure of the vehicle.

According to possible embodiments, the material of the lenticular body <NUM> is of polymeric type, that is a resin such as PMMA (poly methyl methacrylate), PC (polycarbonate) and the like. Said material of the lenticular body <NUM> is therefore at least partially transparent or semitransparent or translucent, one or more opaque portions being able to be included.

As shown, the containment seat <NUM> that extends along a first perimeter edge <NUM> is closed by the lenticular body <NUM> which extends along a second perimeter edge <NUM> at least partially counter-shaped to and overlapping said first perimeter edge <NUM>.

The lighting and/or signaling device <NUM> further comprises at least one light guide <NUM> formed with a transparent polymeric material, such as PC, PMMA or the like, configured to at least partially receive the incoming light beam generated by said light source <NUM>, transmit it by means of total internal reflection along a prevailing propagation direction and output it from the lenticular body <NUM>, as better described below.

Said at least one light guide <NUM> is configured to at least partially receive said light rays <NUM> at an inlet wall <NUM> thereof (called incoupling), convey the light rays <NUM> and extract said light rays <NUM> by means of a rear wall <NUM> thereof (called outcoupling).

In particular, said rear wall <NUM> is provided with a plurality of optical extractor elements <NUM> that extract the light rays <NUM> and transmit them externally to the light guide <NUM> through a front wall <NUM> of the light guide <NUM>, opposite to said rear wall <NUM>, along a transverse direction T-T, perpendicular to the main optical propagation axis X-X.

In particular, said optical extractor elements <NUM> of the rear wall <NUM> comprise local discontinuities or surface alterations or prisms or the like, capable of reflecting the light in specular or scattered manner; moreover, the rear wall <NUM> may be embossed or etched, comprising projected incisions capable of scattering light.

Said front wall <NUM> of the light guide <NUM> in turn may comprise optical elements, such as cylindrical optics or pillow optics or the like, and/or scattering elements, such as an embossing portion and/or an etched portion.

According to the invention, with respect to a cross-section plane passing through said main optical propagation axis X-X and said transverse direction T-T, the inlet wall <NUM> of the light guide <NUM> has a middle section <NUM> with polyline geometry comprising a plurality of rectilinear sections and/or curvilinear sections <NUM> so as to overall be convex on the side of the at least one light source <NUM>. The concept of polyline is to be understood in the broad sense: in other words, as better described below, the polyline is a set of rectilinear sections and/or curvilinear sections <NUM> that overall define a straight or (completely or partially) curved line that has a convexity on the side of the light source <NUM>.

Preferably, especially in the case of light guides having a length which is less than <NUM>, said polyline is configured so that the light rays <NUM>, introduced through the inlet wall <NUM> of the light guide <NUM>, hit the rear wall <NUM> directly or following a single reflection on the front wall <NUM>. Thereby, the scattering of the light rays on the rear wall <NUM> may be controlled so that it is uniform and homogeneous and does not have any light spots. For example, the comparison between <FIG> shows how an inlet wall <NUM> (<FIG>) does not allow sufficiently spacing apart two contiguous light rays <NUM>', <NUM>'' from each other, while an inlet wall <NUM> overall having convex polyline allows increased spacing of said contiguous light rays <NUM>', <NUM>''.

According to a possible embodiment of the present invention, said polyline comprises two mutually angled consecutive rectilinear sections <NUM> which form an angle at the vertex which is greater than <NUM> degrees, on the side of the LED light source <NUM>.

According to a possible embodiment of the present invention, said polyline comprises at least one rectilinear section and one curvilinear section <NUM> that are consecutive to each other so as to obtain an overall convex polyline on the side of the at least one light source <NUM>.

According to a possible embodiment of the present invention, said polyline comprises two curvilinear sections <NUM> that are consecutive to each other so as to obtain an overall convex polyline on the side of the at least one light source <NUM>.

In general, the curvilinear sections <NUM> may be arcs of circle, ellipse, parabola, hyperbole and the like.

According to the invention, the section plane passing through the main optical propagation axis X-X and the transverse direction T-T, the rectilinear and/or curvilinear sections <NUM> forming the polyline related to the cross section of the inlet wall <NUM> of the light guide <NUM> identify each one a skirt of the inlet wall <NUM>.

According to the invention, the skirts of the adjacent inlet wall <NUM> are inclined and joined to one another at a vertex line.

Preferably, each skirt of the inlet wall <NUM> extends in a wavy manner along the longitudinal direction L-L.

In greater detail, and according to a possible embodiment of the present invention, each skirt of the inlet wall <NUM> of the light guide <NUM> comprises a plurality of adjacent optics <NUM> along a longitudinal direction L-L, perpendicular to the transverse direction T-T and the main optical propagation direction X-X. Preferably, said optics <NUM> have a "V" or "U" profile with the vertex facing the light source <NUM>.

Therefore, such optics <NUM> follow one another so as to give the skirt of the inlet wall <NUM> a wavy structure having a related phase, amplitude and frequency.

Preferably, skirts of the inlet wall <NUM> have respective wavy structures having equal phase and/or amplitude and/or frequency. Obliviously, at least one among such phase and/or amplitude and/or frequency of a skirt may be different from the others.

According to a possible embodiment of the present invention, said optics <NUM> are arranged along the longitudinal direction L-L according to a continuous sinusoidal pattern comprising alternating ridges <NUM> and depressions <NUM>, at a constant pitch <NUM>. Pitch <NUM> is the distance between two consecutive ridges <NUM> or depressions <NUM> along said longitudinal direction L-L.

According to a possible embodiment of the present invention, pitch <NUM> and the geometry of the optics <NUM> are configured so that the light beam emitted by each light source <NUM> hits two or more consecutive ridges <NUM> or depressions <NUM> of optics <NUM>.

Preferably, said optics <NUM> have a height, i.e., a distance between the ridges <NUM> and the depressions <NUM>, that is the height of the sinusoid, which is less than <NUM>.

Again, with reference to <FIG>, a first skirt <NUM>' of the inlet wall <NUM> is structured to refract and direct the light beam in a first proximal zone <NUM> of the rear wall <NUM>, while a second skirt <NUM>'' of the inlet wall <NUM> is structured to refract and direct the light beam in a second distal zone <NUM> of the rear wall <NUM>, so as to involve the whole rear wall <NUM>, said first proximal zone <NUM> and second distal zone <NUM> being contiguous to each other. In other words, since the first skirt <NUM>' and the second skirt <NUM>'' of the inlet wall <NUM> lie on respective mutually inclined lying planes, the light may be refracted with a much broader light distribution and thus involving the whole rear wall <NUM> - both the first proximal zone <NUM> and the second distal zone <NUM> - without light concentrations in the first proximal zone <NUM> of the rear wall <NUM>.

According to a possible embodiment of the present invention, a transverse thickness <NUM> of the light guide <NUM> is equal to a subtended cord <NUM> at transverse ends <NUM>, <NUM> of said polyline.

Preferably, in order to optimize the optical efficiency of the system, a light emission distribution <NUM> of said light sources <NUM> has transverse amplitude <NUM> which is comparable, for example equal, to said transverse thickness <NUM> of the light guide <NUM> so as to involve all the skirts.

According to a possible embodiment of the present invention, the light guide <NUM>, at the inlet wall <NUM>, has a pair of transverse appendices <NUM>, on opposite sides with respect to said middle section <NUM> with polyline geometry, so as to facilitate the position of the light guide <NUM> in the container body <NUM>.

As can be appreciated from the above description, the present invention allows overcoming the drawbacks introduced in the known art.

In particular, by virtue of the present invention, the outcoupling surface, or rear wall, of the light guide may be homogeneously lit by means of light rays emitted by the LED.

After being refracted into the inlet wall, or incoupling, said light rays hit the rear wall directly or following a single rebound in the light guide: thereby, the mentioned homogeneity and the absence of undesired light spots may be obtained.

It is therefore possible to provide long and thin light guides and/or light guide plates without the risk of having light spots on the outlet wall, thus creating homogeneous and uniform lighting.

Claim 1:
A lighting and/or signaling device (<NUM>) for vehicles, comprising:
- a container body (<NUM>) that delimits a containment seat (<NUM>) which extends along a first perimeter edge (<NUM>), closed by a lenticular body (<NUM>) which extends along a second perimeter edge (<NUM>) at least partially counter-shaped to and overlapping said first perimeter edge (<NUM>),
- said containment seat (<NUM>) housing at least one LED or mini LED light source (<NUM>) adapted to emit a light beam comprising a plurality of light rays (<NUM>) which extend along a main optical propagation axis (X-X), and at least one light guide (<NUM>) configured to at least partially receive said light rays (<NUM>) at an inlet wall (<NUM>) thereof and to transmit and/or reflect said light rays (<NUM>) onto a rear wall (<NUM>) thereof,
- said rear wall (<NUM>) being provided with a plurality of optical extractor elements (<NUM>) which extract the light rays (<NUM>) and transmit them externally to the light guide (<NUM>) through a front wall (<NUM>) of the light guide (<NUM>), opposite to said rear wall (<NUM>), along a transverse direction (T-T), perpendicular to the main optical propagation axis (X-X),
- characterized in that with respect to a cross-section plane passing through said main optical propagation axis (X-X) and said transverse direction (T-T), said inlet wall (<NUM>) has a middle section (<NUM>) with polyline geometry comprising a plurality of rectilinear sections and/or curvilinear sections (<NUM>) so as to be overall convex on the side of the at least one light source (<NUM>),
wherein the rectilinear and/or curvilinear sections (<NUM>) each identify a skirt of the inlet wall (<NUM>), wherein adjacent skirts of the inlet wall (<NUM>) are inclined and joined to one another at a vertex line.