Lighting system, in particular for a motor vehicle

Abstract

The invention relates to a lighting system (1) which extends in a longitudinal direction, this lighting system (1) being in particular configured to carry out a signalling function for a motor vehicle or a decorative lighting function for a motor vehicle, this lighting system (1) comprising: - a lighting strip (2) extending in the longitudinal direction (Y) and provided with light sources (3), in particular LED light sources, arranged in the longitudinal direction (Y) and spaced apart from one another by a pitch (PITCH), the lighting strip (2) having a width (w);- a diffusing screen (5) extending in the longitudinal direction (Y) and comprising patterns (6), in particular refractive patterns (6), these patterns (6) being for example identical, these patterns (6) being arranged in a tiled manner, in particular in the form of a matrix, each pattern (6) having a concave or convex facet having, longitudinally, a longitudinal profile, and, transversely, a transverse profile.

Description

Lighting system, especially for motor vehicles

[0001] The field of the present invention is that of lighting systems, particularly for motor vehicles.

[0002] Car manufacturers today are integrating the illuminated "pixelated" line into various signaling functions. For example, this function can be selected from: daytime running lights (DRL), turn signals (TI), front position lights (PL), rear lights, brake lights, and rear turn signals.

[0003] This type of system must meet a large number of constraints: Cost (number of LEDs determined by the pitch): the higher the pitch, the lower the cost per cm; remember that LED stands for "light emitting diode" in French, also known by the acronym LED for "light emitting diode" in English, Uniformity of visual appearance when the system is lit, Packaging: in particular minimizing the depth of the system, Optical efficiency, Standardization of parts reused for several projects, Uniform and smooth appearance when not lit.

[0004] The present invention aims to address at least some of these constraints.

[0005] The invention thus relates to a lighting system extending along a longitudinal direction, this lighting system being configured in particular to perform a motor vehicle signaling function or a decorative motor vehicle lighting function, this lighting system comprising: a luminous strip extending along the longitudinal direction and provided with light sources, in particular LEDs, arranged along the longitudinal direction and spaced from each other at a pitch, the luminous strip having a width; a diffusing screen extending along the longitudinal direction and comprising patterns, in particular refractive patterns, these patterns being, for example, identical, these patterns being arranged in a tiling, in particular a matrix (for example, a pattern matrix composed of several rows of parallel patterns), each pattern having a concave or convex facet having, in longitudinal section, a longitudinal profile; andin cross-section, a transverse profile, the longitudinal section being defined along the longitudinal direction and substantially perpendicular to the width of the light band, and the cross-section being perpendicular to the longitudinal direction and substantially parallel to the width of the light band, the radius of curvature of the transverse profile being greater than the radius of curvature of the longitudinal profile, and the diffusing screen having a light exit face, oriented opposite to the light band, and a light entrance face, oriented towards the light band, and the patterns are present on this entrance face and / or this exit face,the luminous strip being placed at a predetermined depth (d) relative to the diffusing screen such that light emitted by the light sources of the luminous strip is refracted by the patterns of the diffusing screen to form a homogeneous-looking image visible along an optical axis to a human observer.

[0006] In the present invention, a "homogeneous-appearing image" is defined as an image that is perceived by the human eye as being homogeneous. For example, a human observer perceives the light emitted by the lighting system as a line that is homogeneously illuminated along its entire length, in particular a line that is uniformly illuminated along its entire length.

[0007] The invention makes it possible, thanks to the patterns, to make the visible result of the light rays emitted by "point" light sources such as LEDs homogenize.

[0008] According to one aspect of the invention, each motif has a concave or convex, cushion-like shape. In particular, each motif has a convex facet on which the longitudinal and transverse profiles are defined.

[0009] The tiling can be of the matrix square type, the matrix rectangular type, or even of the hexagonal type or the tiling of circles of variable or constant size. The tiling can also include shapes of several types and / or several sizes.

[0010] The longitudinal profile of the patterns is advantageously chosen to achieve homogeneity in the resulting light contributions from the different light sources. The longitudinal profile is calculated taking into account the thickness of the material forming the diffusing screen. Other parameters may also be considered in the calculation of the longitudinal profile.

[0011] The transverse profile of the patterns allows for managing light efficiency and concentrating light along the optical axis.

[0012] The longitudinal and transverse profiles of the patterns are constructed to perform different functions. For example, the longitudinal and transverse profiles of the patterns are configured so that the angle of light deviation by the longitudinal profile is approximately twice the angle of deviation by the transverse profile. For example, the angle of light deviation by the longitudinal profile is between 25° and 45°. For example, the angle of deviation by the transverse profile is between 10° and 25°.

[0013] In the present invention, refractive patterns are optical patterns through which light rays propagate according to the laws of refraction.

[0014] In the present invention, the facet of the pattern is concave when the concavity is directed towards the outside of the screen material, and the facet of the pattern is convex when the concavity is directed towards the inside of the screen material.

[0015] The lighting system may also include one or more of the following features, taken alone or in combination.

[0016] The overall elongated shape of the light system can be straight or curved.

[0017] According to one aspect of the invention, the diffusing screen extends along the longitudinal direction, in particular parallel to the light strip.

[0018] According to one aspect of the invention, the diffusing screen is globally flat, and the refractive patterns are aligned on this plane.

[0019] Alternatively, the diffusing screen extends globally along a curved surface, and the refractive patterns are aligned on this global curved surface.

[0020] According to one aspect of the invention, the characteristic size of each motif (for example a diameter of the motif or a side of the motif) is between 0.1 mm and 2 mm, preferably between 0.3 mm and 0.6 mm.

[0021] According to one aspect of the invention, the depth / pitch ratio is between 1 and 2, being in particular substantially equal to 1.5. The depth is the distance between the light strip and the diffusing screen, and the pitch is the distance between successive light sources on the light strip.

[0022] The invention makes it possible in particular to use a depth / pitch ratio which is satisfactory in terms of the homogeneity of the output light, while offering very good luminous efficiency.

[0023] Indeed, to satisfactorily manage light homogeneity, a highly diffusive screen is necessary. Some known systems use a highly diffusive but inefficient film because this film reflects a substantial portion of the light outside the useful cone, resulting in wasted light. For example, for a signaling cone, the useful cone has a horizontal beam angle of approximately 20 degrees and a vertical beam angle of approximately 10 degrees, with increasing photometry from the edge to the center.

[0024] Advantageously, the system according to the invention is configured to achieve an efficiency that is at least equal to 0.5cd / Lm, and preferably at least equal to 0.9 cd / Lm (Candela per Lumen).

[0025] According to one aspect of the invention, the light sources, in particular LEDs, are arranged on the strip in a single row, unlike a matrix arrangement.

[0026] According to one aspect of the invention, the light sources, in particular LEDs, are configured so that they can be switched on simultaneously or sequentially, for example by individual LEDs or by groups of LEDs.

[0027] The invention makes it possible, in particular, to produce an animated image when light sources are switched on sequentially (for example, progressively one after the other). This allows for an animated effect, or for combining signaling functions with a single system, these signaling functions having illuminated areas of different sizes.

[0028] According to one aspect of the invention, the gap between two light sources, in particular LEDs, is between 10 and 15 mm, being for example substantially equal to 13 mm or 14 mm.

[0029] In the invention, the lighting system, with the diffusing screen positioned in front of the light strip at a given depth-to-pitch ratio, is configured such that light rays emitted by a given light source on the light strip are refracted to produce rays exiting the diffusing screen that are parallel to the optical axis. For a given light source on the light strip, the light rays exiting parallel to the optical axis strike the diffusing screen on a portion of the screen that extends towards at least one light source immediately adjacent to that light source.

[0030] Thus, for a given light source (particularly an LED), a light spot is formed (centered on the LED that forms the spot), and the light spot is spread over at least half a step on either side of the given light source. Specifically, the light spot is spread over approximately one step on either side of the given light source, so that this spot extends above (or "vertically") the neighboring light sources.

[0031] This allows for a homogeneous appearance resulting from all the light contributions of the "discrete" light sources (LEDs) on the light strip. In other words, the invention allows for a superposition of spread-out light spots so as to create a substantially homogeneous appearance (for example, with the appearance of a thin light strip) to the eye of a human observer.

[0032] It is worth remembering that it is the longitudinal profile of each pattern that produces the predetermined spread of light.

[0033] As for the transverse profile, it is calculated differently from the longitudinal profile, namely the transverse profile is configured to manage the efficiency of the light beam emitted by the light source (in particular to have a cone of light of the desired angle).

[0034] Preferably, the spacing between light sources is constant along the entire length of the light strip. Alternatively, the spacing between light sources is variable along the light strip. This (non-constant) spacing can vary by + / -20° around a reference value. In particular, the largest spacing can be up to +50% greater than the smallest spacing.

[0035] According to one aspect of the invention, the width of the diffusing screen is between 5 mm and 10 mm.

[0036] According to one aspect of the invention, the lighting system includes a collimating lens configured to collimate transversely the light emitted by the light source.

[0037] The collimation lens has no optical function in the longitudinal axis L.

[0038] According to one aspect of the invention, the collimating lens comprises a light-inlet face and a light-outlet face, the latter being concave and facing away from the light source. The concave shape of the light-outlet face is viewed from inside the collimating lens. More precisely, the concave shape is viewed from a point inside the collimating lens, opposite the light source, which is located at the point where the concavity is being evaluated. Alternatively, the light-outlet face is convex, viewed similarly from inside the collimating lens. The light-inlet face of the collimating lens, opposite the light sources, may have a Fresnel profile with a series of concentric grooves.

[0039] According to one aspect of the invention, the lighting system includes walls, in particular white walls, on either side of the collimation lens.

[0040] According to one aspect of the invention, the walls are extruded, that is to say obtained by an extrusion process.

[0041] Throughout the description, the characteristics described for white walls can be applied to walls in general.

[0042] According to one aspect of the invention, the lens is extruded, that is to say obtained by an extrusion process.

[0043] According to one aspect of the invention, the walls, in particular the white walls, and the collimation lens are co-extruded.

[0044] Coextrusion is achieved in particular by extruding material along the longitudinal direction of the light system.

[0045] In this case, the white walls and the collimation lens can be made by co-extrusion of plastics and / or silicone. The white walls can be made of filled silicone.

[0046] Thanks to the invention, it is possible to have a standard set of light strip, collimation lens, and white walls.

[0047] This standard component can be flexible, allowing it to follow a desired curvature.

[0048] According to one aspect of the invention, the white walls are inclined at a non-zero angle to the optical axis so as to flare out as they move away from the light source.

[0049] According to one aspect of the invention, the white walls are configured to rest on a support (in particular of the printed circuit board type) of the light strip.

[0050] The white walls allow for a controlled distance between the light strip and the collimating lens and / or the diffusing screen. Generally, the walls are configured to hold the collimating lens and adjust its positioning relative to the light sources. The walls also prevent stray rays from the sides by reflecting the light.

[0051] Alternatively, the walls can be optically absorbent, for example be black walls.

[0052] According to one aspect of the invention, the light entry and / or exit face of the collimating lens is cylindrical. In particular, the collimating lens may be a cylindrical part manufactured by extrusion. "Cylindrical shape" is understood to mean that this shape is present on the part directly obtained from the extrusion process. This part may then be bent for implantation in the lighting system.

[0053] According to one aspect of the invention, the diffusing screen is formed on a protective glass (or protective diopter) of the light system.

[0054] According to one aspect of the invention, the system comprises a housing configured to accommodate the light strip, the diffusing screen and possibly other optical components, and the protective glass is configured to close this housing.

[0055] In this case, the patterns of the diffusing screen are advantageously on the entrance face, that is to say the inner face of the protective glass.

[0056] This allows the designs to be inside the case, namely in a closed and protected space, thus preventing damage or dirt that would affect the operation of these designs.

[0057] According to one aspect of the invention, the diffusing screen is made with the protective glass in a monolithic manner, for example by molding a plastic-based material.

[0058] According to one aspect of the invention, the collimating lens comprises an entrance face (facing the light strip) that is concave and a flat exit face. The concave shape is viewed from inside the collimating lens, as described above. Alternatively, the exit face is convex, viewed similarly from inside the collimating lens.

[0059] According to another aspect of the invention, the collimating lens has a concave exit face and a flat entrance face (facing the light strip). The concave shape is viewed from inside the collimating lens, as described above. Alternatively, the exit face is convex, viewed similarly from inside the collimating lens.

[0060] According to another aspect of the invention, the diffusing screen is formed by a film, for example, glued (for example, by an OCA optical adhesive for "Optically Clear Adhesive" in English) onto an entrance face (the inner face) of the protective glass.

[0061] The protective glass, which does not include the patterns, can thus be extruded. This simplifies the manufacturing of this protective glass.

[0062] According to another aspect of the invention, the diffusing screen is made by overmolding on the inner or outer face of the protective glass.

[0063] In particular, in the case of overmolding on the outer face of the protective glass, the patterns of the diffusing screen are overmolded with a protective material, in particular a material which is polyurethane.

[0064] According to one aspect of the invention, the refractive index of the protective material is chosen to be significantly lower than the refractive index of the protective glass and the film serving as a diffusing screen. "Significantly lower" means that the difference between the two indices is greater than or equal to 0.05, and preferably greater than or equal to 0.1.

[0065] According to one aspect of the invention, the refractive index of the protective material is chosen to be significantly higher than the refractive index of the protective glass and the film serving as a diffusing screen. "Significantly higher" means that the difference between the two indices is greater than or equal to 0.05, and preferably greater than or equal to 0.1.

[0066] A significant difference between the two indices is necessary to ensure that the diffusing screen patterns are optically effective.

[0067] According to one aspect of the invention, the protective material has patterns on its outer face, that is to say on its face opposite to that which is in contact with the diffusing screen.

[0068] According to one aspect of the invention, the geometry of the diffusing screen patterns takes into account the indices of the protective material, the diffusing screen film and the ice of the protective glass and possibly other optical components in the path of the rays.

[0069] According to one aspect of the invention, the diffusing screen is made with the collimating lens in a monolithic (meaning one-piece) manner, for example by molding a plastic-based material.

[0070] The diffusing screen and the collimating lens are thus formed as a single unit. In other words, the diffusing screen is not made from a separate piece (for example, a protective glass) distinct from the collimating lens. For example, the diffusing screen and the collimating lens are made from the same piece of material.

[0071] According to one aspect of the invention, the collimating lens comprises a flat exit face on which the diffusing screen is disposed.

[0072] According to one aspect of the invention, the collimating lens has a convex entrance face (facing the light strip). The entrance face of the collimating lens can be positioned at a relatively short distance from the light sources to collect the rays emanating from them.

[0073] According to one aspect of the invention, the diffusing screen and the collimating lens define a molded part, in particular made of plastic.

[0074] According to another aspect of the invention, the diffusing screen is formed by a film, for example, glued (for example, by an OCA optical adhesive for "Optically Clear Adhesive") onto an exit face of the collimating lens.

[0075] The collimation lens, which does not include the patterns, can thus be extruded. This simplifies the manufacturing of this collimation lens and, if necessary, the side walls of the collimation lens. Indeed, the patterns of the diffusing screen, due to their shape, cannot be directly produced by extrusion.

[0076] According to another aspect of the invention, the diffusing screen is made by overmolding on an exit face of the collimation lens.

[0077] In other words, the collimation lens can be manufactured from an extruded material, and then the patterns can be overmolded onto it. Overmolding has the advantage of preserving the flexibility of the collimation lens.

[0078] In general, the patterns of the diffusing screen are covered, in particular overmolded, with an additional protective material, in particular a material which is polyurethane.

[0079] According to one aspect of the invention, patterns can be created on a previously extruded part (the collimation lens) by a subsequent treatment such as stamping. This treatment allows for the creation of the specific shapes of the patterns. It can be carried out while the material is still hot, particularly after it exits the extruder. This allows for patterns to be present at the exit point, with the stamping process resulting in outward-facing patterns.

[0080] According to one aspect of the invention, the refractive index of the protective material is chosen to be significantly lower than the refractive index of the diffusing screen. By "significantly lower" is understood to mean that the difference between the two indices is greater than or equal to 0.05, and preferably greater than or equal to 0.1.

[0081] According to one aspect of the invention, the refractive index of the protective material is chosen to be significantly higher than the refractive index of the diffusing screen. By "significantly higher" is understood to mean that the difference between the two indices is greater than or equal to 0.05, and preferably greater than or equal to 0.1.

[0082] A significant difference between the two indices is necessary to ensure that the diffusing screen patterns are optically effective.

[0083] This is particularly applicable when the patterns of the diffusing screen are overmolded with a protective material, in particular a material which is polyurethane, and the patterns are at the interface of two materials having distinct indices, for example polyurethane / silicone.

[0084] According to one aspect of the invention, the protective material has patterns on its outer face, that is, on the face opposite to the one in contact with the diffusing screen. In this case, the protective material may have any refractive index (including one equal to the index of the extruded lens).

[0085] According to one aspect of the invention, the protective material may be present only at the junction with the diffusing screen. Alternatively, the protective material envelops the diffusing screen and also the outer walls of the partitions. As a further alternative, the protective material may envelop the diffusing screen, the outer walls of the partitions, and the underside of an electronic board that carries the light sources. A significant difference between the two indices is necessary to ensure that the patterns of the diffusing screen are optically effective.Preferably, before molding the protective material, a mold of the patterns must first be made, either the patterns are made on a part (the collimating lens) previously extruded, by a subsequent treatment such as pad stamping, or the protective material has patterns on its outer face, that is to say on its face opposite to that which is in contact with the diffusing screen, and in this case, the first overmolding must have an index which differs from the second overmolding.

[0086] The protective material can be configured to provide a smooth surface over the patterns of the diffusing screen.

[0087] According to one aspect of the invention, the lighting system includes a material bridge which joins two facing walls, the material bridge being interposed in particular between the light sources and a collimation lens.

[0088] The material bridge is particularly advantageous when increasing the distance between light sources. In this case, it would be necessary to proportionally increase the depth of the collimating lens. This increase could compromise the overall mechanical strength. To overcome this problem, the material bridge can act as reinforcement.

[0089] According to one aspect of the invention, the material bridge is optically neutral, namely it has no additional optical function.

[0090] Alternatively, the material bridge is configured to form an additional lens. This improves the overall optical performance.

[0091] The material bridge can be above the light sources.

[0092] According to one aspect of the invention, the material bridge is configured to encapsulate the light sources. In this case, the material bridge may have a convex shape. This improves the extraction of light from the LEDs.

[0093] According to one aspect of the invention, the functions performed by the lighting system are selected from: daytime running lights (DRL), turn indicators (TI), position lights (PL) at the front, rear lights, brake lights, rear turn indicators, and RGB decorative lighting functions, including animated decorative lighting functions, inside and / or outside vehicles.

[0094] Other features, details and advantages of the invention will become clearer upon reading the following description on the one hand, and several illustrative and non-limiting examples of embodiments given with reference to the attached schematic drawings on the other hand, in which:

[0095] Laest is a representation, in longitudinal section, of a lighting system according to the invention;

[0096] This is a cross-sectional representation of the light system of the;

[0097] This is a perspective representation of an individual motif on the diffusing screen of the light system;

[0098] This corresponds to the, with representation of the light rays and the image formed;

[0099] Laest is a cross-sectional representation of the lighting system according to a particular embodiment;

[0100] Laest is a cross-sectional representation of the lighting system according to another embodiment;

[0101] Laest is a cross-sectional representation of the lighting system according to yet another embodiment;

[0102] Laest is a cross-sectional representation of the lighting system according to yet another embodiment;

[0103] This is a cross-sectional representation of another example of an embodiment of the invention;

[0104] This is a representation of another example of the realization of the invention;

[0105] This is a representation of another example of the realization of the invention;

[0106] This is a representation of a variant of the invention;

[0107] This is a representation of another variant of the invention;

[0108] Laest is a representation with a protective glass;

[0109] This is a representation of another example of the realization of the invention;

[0110] This is a representation of another example of an embodiment of the invention.

[0111] The features, variations, and different embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variations of the invention may include only a selection of features, described hereafter in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from prior art.

[0112] We have represented on the (in longitudinal section) and the (in transverse section), a lighting system 1 according to an example of an embodiment of the invention, which extends along a longitudinal direction Y.

[0113] This lighting system 1 is configured to perform a motor vehicle signaling function or an interior decorative lighting function. For example, this function can be selected from: daytime running lights (DRL), turn signals (TI), front position lights (PL), rear lights, brake lights, rear turn signals, and animated color decorations inside vehicles.

[0114] The lighting system 1 comprises a light strip 2 extending along the longitudinal direction Y and provided with light sources 3, here LEDs, arranged along the longitudinal direction Y and spaced, along this direction X, from each other according to a pitch noted "PITCH".

[0115] The lighting system 1 further includes a diffusing screen 5 extending along the longitudinal direction Y and containing identical refractive patterns 6 arranged in a matrix. For example, the pattern matrix is ​​composed of several rows of parallel patterns. Other types of tessellations besides a matrix can be considered.

[0116] As illustrated in the figure, each motif 6 has a convex facet 7 (i.e., a bulging facet opposite the light band 2) having, in longitudinal section ( ), a longitudinal profile L, and, in transverse section ( ), a transverse profile T, the longitudinal section being defined along the longitudinal direction Y and the transverse section (in the Z axis) being perpendicular to the longitudinal direction Y and parallel to the width w of the light band 2, and the radius of curvature of the transverse profile T is greater than the radius of curvature of the longitudinal profile L. In a variant, each motif 6 could have a concave facet (i.e., a bulging facet oriented towards the light band 2).

[0117] As illustrated in the figure, the light strip 2 is placed at a predetermined depth d relative to the diffusing screen 5 so that light emitted by the light sources 3 of the light strip 2 is refracted by the patterns 6 of the diffusing screen 5 to form a homogeneous-looking image 10 visible along an optical axis OA by the eye of a human observer HO.

[0118] In the present invention, a "homogeneous-appearing image" is defined as an image that is perceived by the human eye as being homogeneous. For example, a human observer perceives the light emitted by the light system 1 as a line / strip that is homogeneously illuminated along its entire length.

[0119] Each motif 6 has a convex, cushion-like shape. Here, each motif 6 has a convex facet oriented opposite to the luminous band 2, and on which the longitudinal profile L and the transverse profile T are defined.

[0120] The longitudinal profile L of the patterns 6 is advantageously chosen to obtain the homogeneity of the result of the light contributions from the different light sources 3. The longitudinal profile L is calculated taking into account the thickness of the material that forms the diffusing screen 5. Other parameters can be taken into account for the calculation of the longitudinal profile L. For example, the geometry of the patterns 6 of the diffusing screen 5 takes into account the indices of the protective material, the film forming the diffusing screen 5 and the glass of the protective glass 27 and possibly other optical components in the path of the rays.

[0121] The transverse profile T of the patterns 6 allows for managing light efficiency and concentrating light along the optical axis OA.

[0122] The longitudinal profile L of pattern 6 and the transverse profile T of pattern 6 are thus constructed to perform different functions. For example, the angle of light deviation by the longitudinal profile is between 25° and 45°. For example, the angle of deviation by the transverse profile is between 10° and 25°.

[0123] The general elongated shape of the light system 1 can be straight or curved.

[0124] The diffusing screen 5 extends along the longitudinal direction Y, parallel to the luminous strip 2.

[0125] The diffusing screen 5 has a light exit face 14, oriented opposite to the light strip 2, and the refractive patterns 6 are present on this exit face 14.

[0126] The diffusing screen 5 is generally flat, and the refractive patterns 6 are aligned on this plane.

[0127] In an unillustrated variant, the diffusing screen 5 extends globally along a curved surface, and the refractive patterns 6 are aligned on this global curved surface.

[0128] The characteristic size of each pattern 6 (for example a diameter of pattern 6 or a side of pattern 6) is between 0.1 mm and 2 mm, preferably between 0.3 mm and 0.6 mm.

[0129] The depth / pitch ratio, therefore the d / PITCH ratio, is between 1 and 2, being notably approximately equal to 1.5. The depth d is the distance between the light strip 2 and the diffusing screen 5, and the pitch called "PITCH" is the distance between the light sources 3 on the light strip 2.

[0130] The invention makes it possible in particular to use a depth / pitch ratio which is satisfactory in terms of the homogeneity of the output light, while offering very good luminous efficiency, as well as good compactness and a reasonable number of LEDs, therefore a reasonable cost.

[0131] Advantageously, the system according to the invention is configured to achieve an efficiency that is at least equal to 0.5 cd / Lm, and preferably at least equal to 0.9 cd / Lm (candela per lumen). Advantageously, the system according to the invention is configured to achieve an efficiency that is substantially equal to 0.9 cd / Lm.

[0132] The 3 light sources (LEDs) are arranged on the strip in a single row, unlike a matrix arrangement.

[0133] If desired, the 3 light sources (LEDs) are configured so that they can be switched on simultaneously or sequentially.

[0134] The invention makes it possible, in particular, to produce an animated image when the light sources 3 are switched on sequentially (for example, progressively one after the other). This provides an animation effect.

[0135] According to one aspect of the invention, the pitch between two light sources 3 (LEDs) is between 10 and 15 mm, being for example substantially equal to 13 mm or 14 mm.

[0136] The edge of pattern 6 is the place that gives the greatest deviation of light.

[0137] In the invention, the lighting system 1, with the diffusing screen 5 positioned in front of the light strip 2 with a given d / PITCH ratio, is configured such that light rays emitted by a given light source 3 of the light strip 2 are refracted to produce, at the output of the diffusing screen 5, rays parallel to the optical axis OA. For a given light source 3 of the light strip 2, the light rays exiting parallel to the optical axis OA strike the diffusing screen 5, on an area of ​​this diffusing screen 5 that extends towards at least one light source 3 immediately adjacent to this given light source 3.

[0138] Thus, for a given light source 3 (here LED1), a light spot LZ1 (see image) is formed (centered on the LED that forms the spot), and the light spot LZ1 is spread over at least half a pitch (0.5 pitch) on either side of the given light source 3 (LED1). Preferably, the light spot is spread approximately one pitch on either side of the given light source 3 (LED1), so that this spot is spread above (i.e., "vertically") the neighboring light sources 3 (LED2 and LED3). These LEDs 2 and 3 produce the respective light spots LZ2 and LZ3. The light spots LZ1, LZ2, LZ3, etc., form a homogeneous line of light.

[0139] This allows for a homogeneous appearance resulting from all the light contributions of the "discrete" light sources 3 (LEDs) on the light strip 2. In other words, the invention allows for a superposition of light spots LZ1, LZ2, LZ3, etc. spread out so as to create a substantially homogeneous appearance (for example with the appearance of a thin light strip 2) for the eye of a human observer.

[0140] It is recalled that it is the longitudinal profile L of each pattern 6 which produces the predetermined light spreading.

[0141] As for the transverse profile T, it is calculated differently from the longitudinal profile L, namely the transverse profile T is configured to manage the efficiency of the light beam emitted by the light source 3 (in particular to have a cone of light of desired angle).

[0142] According to one aspect of the invention, the width of the diffusing screen 5 is between 5 mm and 10 mm.

[0143] We will now describe an example of the implementation of the invention. In this embodiment of the invention, the lighting system 1 comprises a collimating lens 20 configured to collimate transversely the light emitted by the light source 3.

[0144] The collimation lens 20 has no optical function in the longitudinal axis L.

[0145] The collimation lens 20 includes a light exit face 22 which is flat, and an entrance face 21 which is turned towards the light source 3 and is concave in shape.

[0146] The light system 1 includes white walls 24 on either side of the collimation lens 20, and which extend along the longitudinal direction Y.

[0147] The white walls 24 and the collimation lens 20 are co-extruded.

[0148] Coextrusion is achieved in particular by extruding material along the longitudinal Y direction of the light system 1.

[0149] In this case, the white walls 24 and the collimation lens 20 can be made by co-extrusion of plastics and / or silicone.

[0150] Thanks to the invention, it is possible to have a standard set of 2 light strips, 20 collimation lenses, and 24 white walls.

[0151] This standard component can be flexible, allowing it to follow a desired curvature.

[0152] The white walls 24 are inclined at a non-zero angle to the optical axis OA so as to flare out as they move away from the light source 3.

[0153] The white walls are configured to rest on a support 25, here of the printed circuit board type, of the light strip 2.

[0154] Thus the white walls allow a controlled distance between the light strip 2 and the collimation lens 20 and / or the diffusing screen 5. The white walls 24 can surround the support 25, here of the printed circuit board type, also on the back of the board.

[0155] The collimation lens 20 is made of silicone.

[0156] According to one aspect of the invention, the light inlet face 21 and / or the light outlet face 22 of the collimating lens 20 is cylindrical in shape along the longitudinal direction Y.

[0157] The diffusing screen 5 is formed on a protective glass 27 (or protective diopter) of the luminous system 1.

[0158] According to one aspect of the invention, the system comprises a housing 28 configured to house the light strip 2, the diffusing screen 5 and possibly other optical components, and the protective glass 27 is configured to close this housing 28.

[0159] In this case, patterns 6 of the diffusing screen 5 are advantageously on the entrance face 29, that is to say the inner face of the protective glass 27.

[0160] This allows the patterns 6 to be inside the housing 28, namely in a closed and protected space, thus avoiding damage or dirt which would affect the operation of these patterns 6. Thus, the diffusing screen 5 has an inlet face 29 of the light, oriented towards the light strip 2, and the refractive patterns 6 are present on this inlet face.

[0161] The diffusing screen 5 is made with the protective glass 27 in a monolithic manner, for example by molding a plastic-based material.

[0162] We will now describe, with reference to another example of an embodiment of the invention, in which the collimating lens 20 has a concave exit face 31 and a flat entrance face 30 (facing the light strip 2).

[0163] In the example embodiment of the, the diffusing screen 5 is formed by a film 32 for example glued (for example by an OCA (Optically Clear Adhesive) optical glue or optically transparent adhesive) on an entrance face 29 (the inner face) of the protective glass 27.

[0164] The protective glass 27, which does not include the patterns 6, can therefore be extruded. This simplifies the manufacture of this protective glass 27.

[0165] In the example of the realization of the, the diffusing screen 5 is made by overmolding on the external face 33 of the protective glass 27.

[0166] The 6 patterns of the diffusing screen are overmolded with a protective material 35, specifically a polyurethane material. The patterns 6 are at the interface of two materials with distinct indices, for example polyurethane / polycarbonate, or silicone / PMMA (PMMA stands for polymethyl methacrylate), or silicone / polycarbonate.

[0167] The refractive index of the protective material 35 is chosen to be significantly lower than the refractive index of the protective glass 27 and the film serving as a diffusing screen 5.

[0168] We will now describe, with reference to another example of an embodiment of the invention, in which the diffusing screen 5 is made with a collimating lens 120 in a monolithic (meaning monobloc) manner, for example by molding a plastic-based material.

[0169] The diffusing screen 5 and the collimating lens 120 thus form a single piece. In other words, the diffusing screen 5 is not made from a separate piece (for example, a protective glass) distinct from the collimating lens 120. For example, the diffusing screen 5 and the collimating lens 120 are made from the same piece, of the same material. The protective glass can be a separate piece added to protect the diffusing screen 5 and the collimating lens 120, as illustrated in the figure.

[0170] The collimating lens 120 has a convex entrance face 122 (facing the light strip). The entrance face 122 of the collimating lens 120 can be positioned at a relatively short distance from the light sources to collect the rays emanating from them.

[0171] According to another embodiment of the invention illustrated in the figure, the diffusing screen 5 is formed by a film 125 for example glued (for example by an OCA optical glue for "Optically Clear Adhesive" in English or optically transparent adhesive) on an exit face 121, which is for example flat, of the collimation lens 120.

[0172] The collimation lens 120, which does not include the patterns, can thus be extruded. This simplifies the manufacture of this collimation lens 120 and, if necessary, of the walls 24 on the sides of the collimation lens 120. Indeed, the patterns of the diffusing screen 5, due to their shape, cannot be directly produced by extrusion.

[0173] Alternatively, the diffusing screen 5 could be made by overmolding onto the exit face 121 of the collimation lens 120.

[0174] In other words, the 120 collimation lens can be manufactured from an extruded material, and then the patterns can be overmolded onto it. Overmolding has the advantage of preserving the flexibility of the 120 collimation lens.

[0175] In another embodiment of the invention illustrated on the figure, the patterns of the diffusing screen 5 are overmolded with an additional protective material 126, in particular a material which is polyurethane.

[0176] Alternatively, patterns can be created on a pre-extruded part (the 120 collimation lens) through a subsequent treatment such as stamping. This treatment allows for the creation of the specific pattern shapes. It can be performed while the material is still hot, particularly after it exits the extruder. This allows for patterns to be applied at the exit point, with the stamping process creating outward-facing patterns.

[0177] According to one aspect of the invention, the refractive index of the protective material is chosen to be significantly smaller than the refractive index of the diffusing screen 5. By "significantly smaller" it is understood that the difference between the two indices is greater than or equal to 0.05, and preferably greater than or equal to 0.1.

[0178] According to one aspect of the invention, the refractive index of the protective material is chosen to be significantly greater than the refractive index of the diffusing screen 5. By "significantly greater" it is understood that the difference between the two indices is greater than or equal to 0.05, and preferably greater than or equal to 0.1.

[0179] A significant difference between the two indices is needed to ensure that the patterns of the diffusing screen 5 are optically effective.

[0180] This is particularly applicable when the patterns of the diffusing screen 5 are overmolded with a protective material 126, in particular a material which is polyurethane, and the patterns are at the interface of two materials having distinct indices, for example polyurethane / silicone.

[0181] According to one aspect of the invention, the protective material 126 has patterns on its outer face, that is to say on its face opposite to that which is in contact with the diffusing screen 5. In this case, the protective material may have any refractive index (including equal to the index of the extruded lens).

[0182] According to one aspect of the invention, the protective material 126 may be present only at the junction with the diffusing screen 5, as illustrated in the.

[0183] Alternatively, the protective material 126 envelops the diffusing screen 5 and also the outer walls of the low walls 24, as illustrated on the.

[0184] Alternatively, the protective material 126 can envelop the diffusing screen 5, the outer walls of the walls 24 and the underside of an electronic board 127 which carries the light sources 3, as illustrated in the.

[0185] The protective material 126 can be configured to provide a smooth surface over the patterns of the diffusing screen 5.

[0186] In another embodiment of the invention illustrated on the, the lighting system includes a material bridge 128 which joins two opposite walls 24, the material bridge 128 being interposed between the light sources 3 and the collimation lens 120.

[0187] The material bridge 128 is particularly advantageous when increasing the distance between the light sources 3. In this case, it would be necessary to proportionally increase the depth of the collimation lens 120. This increase could compromise the overall mechanical strength. To overcome this problem, the material bridge can act as a reinforcement.

[0188] In the example described, the material bridge 128 is configured to form an additional lens. This improves the overall optical performance.

[0189] The material bridge 128 is above the light sources 3.

[0190] In another embodiment of the invention illustrated in Figure 1, the material bridge 128 is configured to encapsulate the light sources 3. In this case, the material bridge 128 may have a concave shape, viewed from inside the lens. This improves the extraction of light from the LEDs.

Claims

A lighting system (1) extending along a longitudinal direction, this lighting system (1) being configured in particular to perform a motor vehicle signaling function or a motor vehicle decorative lighting function, this lighting system (1) comprising: a light strip (2) extending along the longitudinal direction (Y) and provided with light sources (3), in particular LEDs, arranged along the longitudinal direction (Y) and spaced from each other according to a pitch (PITCH), the light strip (2) having a width (w), a diffusing screen (5) extending along the longitudinal direction (Y) and comprising patterns (6), in particular refractive patterns (6), these patterns (6) being for example identical, these patterns (6) being arranged according to a tiling, in particular a matrix, each pattern (6) having a facet (7), concave or convex, having, in longitudinal section, a longitudinal profile (L), and, in transverse section, a transverse profile (T),the longitudinal section being defined along the longitudinal direction (Y) and substantially perpendicular to the width (w) of the luminous strip (2), and the transverse section being perpendicular to the longitudinal direction (Y) and substantially parallel to the width (w) of the luminous strip (2), the radius of curvature of the transverse profile being greater than the radius of curvature of the longitudinal profile (L), and the diffusing screen (5) having a light exit face, oriented opposite to the luminous strip (2), and a light entrance face, oriented towards the luminous strip (2), and the patterns (6) being present on this entrance face and / or this exit face,the luminous strip (2) being placed at a predetermined depth (d) relative to the diffusing screen (5) such that light emitted by the light sources (3) of the luminous strip (2) is refracted by the patterns (6) of the diffusing screen (5) to form a homogeneous-looking image visible along an optical axis (OA) to a human observer. lighting system (1) according to the preceding claim, wherein the characteristic size of each motif (6), for example a diameter of the motif (6) or a side of the motif (6), is between 0.1 mm and 2 mm, preferably between 0.3 mm and 0.6 mm. Light system (1) according to any one of the preceding claims, wherein the depth / pitch ratio is between 1 and 2, in particular being substantially equal to 1.5, the depth being the distance between the light strip (2) and the diffusing screen (5), and the pitch is the distance between the light sources (3) on the light strip (2). Light system (1) according to any one of the preceding claims, wherein the light system (1) comprises a collimating lens (20) configured to collimate transversely the light emitted by the light source, and in particular the collimating lens comprises a light inlet face (21) and a light outlet face, outlet face (22) which is turned away from the light source and convex in shape. Light system according to the preceding claim, wherein the diffusing screen (5) is made with the collimating lens (20) in a monolithic manner, for example by molding a plastic-based material. Light system (1) according to the preceding claim, wherein the diffusing screen (5) and the collimating lens (20) define a molded part, in particular made of plastic. Light system (1) according to claim 5, wherein the diffusing screen (5) is formed by a film for example glued onto an exit face of the collimation lens (20). Light system (1) according to claim 5 or 6, wherein the diffusing screen (5) is made by overmolding on an exit face of the collimation lens (20). Light system (1) according to any one of claims 5 to 8, wherein the patterns (6) of the diffusing screen (5) are overmolded with an additional protective material, in particular a material which is polyurethane. Lighting system (1) according to any one of the preceding claims, wherein the lighting system comprises a material bridge which joins two opposite walls, the material bridge being interposed in particular between the light sources and a collimation lens (20). Light system (1) according to the preceding claim, wherein the material bridge is configured to form an additional lens. Light system (1) according to claim 10 or 11, wherein the material bridge is configured to encapsulate the light sources. Light system (1) according to any one of claims 1 to 4, wherein the diffusing screen (5) is formed on a protective glass (27) of the light system (1), and the system comprises a housing configured to accommodate the light strip (2), the diffusing screen (5) and any other optical components, and the protective glass (27) is configured to close this housing. lighting system (1) according to the preceding claim, wherein the diffusing screen (5) is made with the protective glass (27) in a monolithic manner, for example by molding a plastic-based material. Light system (1) according to claim 13, in which the diffusing screen (5) is formed by a film (32) for example glued onto an entrance face of the protective glass (27). Light system (1) according to claim 13, wherein the diffusing screen (5) is made by overmolding on the inner or outer face of the protective glass (27). Light system (1) according to the preceding claim, wherein, in the case of overmolding on the external face of the protective glass (27), the patterns (6) of the diffusing screen (5) are overmolded with a protective material, in particular a material which is polyurethane. Lighting system (1) according to any one of the preceding claims, wherein the functions performed by the lighting system (1) are selected from: daytime running lights, direction indicators, front lights, rear lights, stop lights, rear direction indicators, and animated RGB decorative lighting functions. Lighting system (1) according to claim 4, or any one of claims 1 to 3 or 5 to 18 in combination with claim 4, comprising walls on either side of the collimating lens. Lighting system (1) according to the preceding claim, in which the walls are extruded. Light system (1) according to claim 4, or any one of claims 1 to 3 or 5 to 20 in combination with claim 4, wherein collimation lens is extruded. Lighting system (1) according to any one of claims 19 to 21, wherein the walls and the collimating lens are co-extruded.

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