ILLUMINATION DEVICE FOR IMAGE OF A VIRTUAL ILLUMINATED SURFACE OF A COLLECTOR

Description

Technical field

[0001] The invention relates to the field of lighting and light signaling, more particularly in the automotive field. Prior art

[0002] The published patent document FR 3 047 541 A1 discloses a lighting device comprising two optical modules arranged opposite each other. Each of these two optical modules essentially comprises a light source and a collector with a reflective surface. These two light sources are arranged on two opposite faces of a common support. Each of the reflective surfaces is a surface of revolution in a half-space delimited by the common support of the light sources. The two reflective surfaces thus form two half-shells opposite each other. One of the two optical modules is configured to form a lighting beam with a horizontal cutoff, corresponding to a so-called "low-beam" beam. To do this, the module comprises a reflective surface with a so-called "cutoff" edge located at a focus of the reflective surface.Rays encountering the surface in question behind the cut-off edge are reflected towards an upper part of a projection lens while those passing in front of the edge in question are not deflected and encounter a lower part of the lens in question. This phenomenon ensures an essentially horizontal cut-off of the beam. The other of the two optical systems operates in essentially the same way, except that the focus of the reflecting surface is located in front of the cut-off edge. The beam produced by the second optical system is combined with that of the first system to produce a high-beam type illumination beam, i.e. a beam without a horizontal cut-off. This configuration is interesting in that it exploits the cut-off beam to produce a high-beam type beam.

[0003] Such a lighting device has the disadvantage of requiring high precision in the positioning of the folder and the cutting edge. Also, the projection lens must be a thick lens due to its short focal length, which increases its weight and complicates its production, such as shrinkage defects. In addition, the collector has a certain height and, therefore, a certain height requirement.

[0004] Document FR 3 038 695 A1 describes a lighting device for producing a cut-off beam using a flat reflector and a collector. Statement of the invention

[0005] The invention aims to overcome at least one of the drawbacks of the aforementioned state of the art. More particularly, the invention aims to propose a lighting and / or signaling module or device which is compact and more economical to produce.

[0006] The invention, defined in claim 1, relates to a light device, in particular for a motor vehicle, comprising a light source capable of emitting light rays; a collector with a reflective surface configured to collect and reflect the light rays emitted by the light source; an optical system configured to project the light rays coming from the reflective surface into a light beam along an optical axis of the light device; remarkable in that the light device comprises a mirror configured to form a virtual image of the light source and the reflective surface of the collector, and the optical system is configured to form an image of said virtual image.

[0007] The light source and the reflective surface form a light module. A light module is capable of forming a light beam. The light device may comprise several light modules. In the presence of a single light module, the light device is similar to the light module. The light device forms an autonomous assembly in that each of its components, such as for example the light source(s), the collector(s) and the optical system, is rigidly connected to the other components, in particular via a specific support (not detailed), and is thus optically positioned relative to the other components. One or more light devices may thus be arranged in a projector housing in order to perform, where appropriate in combination, all the regulatory lighting and signaling functions.

[0008] According to an advantageous embodiment of the invention, the reflecting surface of the collector and the mirror are configured so that the light rays reflected by a rear part of said reflecting surface are parallel to the optical axis or have, in a vertical plane and relative to said axis, an angle of inclination less than or equal to 25°, preferably less than or equal to 10°.

[0009] According to an advantageous embodiment of the invention, the mirror is flat and parallel to the optical axis or is inclined relative to said optical axis by an angle of less than 10°.

[0010] According to an advantageous embodiment of the invention, the light source is configured to emit the light rays in a main direction perpendicular to the optical axis or inclined relative to a direction perpendicular to said optical axis by an angle of less than 25°.

[0011] According to an advantageous embodiment of the invention, the reflecting surface of the collector has a parabolic or elliptical profile. Preferably, it is a surface of revolution of said profile. The revolution is around an axis advantageously parallel to the optical axis. According to a variant, the reflecting surface is a free-form surface or a swept surface or an asymmetrical surface. It can also comprise several sectors.

[0012] According to an advantageous embodiment of the invention, the mirror extends in an extension, towards the optical system, of the reflecting surface of the collector.

[0013] According to an advantageous embodiment of the invention, the reflective surface of the collector is configured to reflect the light rays emitted by the light source in a main direction diverging from the optical axis.

[0014] According to an advantageous embodiment of the invention, the mirror is formed on the collector.

[0015] According to an advantageous embodiment of the invention, the light source is arranged on a substrate, the mirror being aligned with said substrate.

[0016] According to an advantageous embodiment of the invention, the reflective surface of the collector is configured to reflect the light rays emitted by the light source in a main direction converging with the optical axis, said optical axis passing through the substrate.

[0017] According to an advantageous embodiment of the invention, the optical system has a focus located on an area located between the virtual light source and the virtual reflective surface.

[0018] According to an advantageous embodiment of the invention, the focus of the optical system is located on the virtual reflecting surface, behind the virtual light source along the optical axis.

[0019] According to an advantageous embodiment of the invention, the optical system comprises a lens corresponding to a portion of converging lens centered on a virtual optical axis parallel to the optical axis and passing through the focus of the optical system.

[0020] According to the invention, the reflective surface of the collector has a rear edge, the light beam being a beam with horizontal cut-off, said cut-off being an image of said rear edge.

[0021] According to an advantageous embodiment of the invention, the light source and the collector are located above the optical axis when the light device is in the operational position, the cut-off of the light beam being a lower cut-off.

[0022] According to an advantageous embodiment of the invention, the light source and the collector are located below the optical axis when the light device is in the operational position, the cut-off of the light beam being an upper cut-off.

[0023] According to an advantageous embodiment of the invention, the light source, the collector and the light beam are a first light source, a first collector and a first light beam, respectively, the light device comprising a second light source and a second collector with a reflective surface configured to collect and reflect the light rays emitted by the second light source, the optical system being configured to project the light rays coming from said reflective surface into a second light beam along an optical axis of the device and corresponding to an image of said reflective surface.

[0024] The first collector and the first light source form a first light module and the second collector and the second light source form a second light module.

[0025] Advantageously, the light device is configured so that the second light beam is a real image of the reflective surface of the second collector illuminated by the second light source. For this purpose, the light rays reflected by the reflective surface of the second collector are transmitted to the optical system without being reflected by a mirror, unlike the light rays reflected by the reflective surface of the first collector.

[0026] According to an advantageous embodiment of the invention, the first collector and the first light source are opposite, with respect to the optical axis, to the second collector and the second light source, respectively; or the first collector and the first light source, on the one hand, and the second collector and the second light source, on the other hand, are arranged side by side.

[0027] The measures of the invention are interesting in that they make it possible to produce a compact light module or device, easy to assemble with a reduced number of parts and capable of performing different lighting and / or signaling functions. More particularly, imaging the illuminated reflective surface of the collector makes it possible to produce a light beam with a concentration of light at a position vertically off-centered from said beam. Also, the invention makes it very easy to turn the image produced and thus to modulate the light beam(s) to the lighting and / or signaling functions to be provided, in particular the “code” and “high” lighting functions.

[0028] Other features and advantages of the present invention will be better understood with the aid of the description and the drawings. Brief description of the drawings

[0029] [ Fig 1] is a schematic representation of a light device according to a first embodiment of the invention. [ Fig 2 ] is a perspective view of the upper collector of the light device of the Figure 1 . [ Fig 3 ] is a view of the illuminated inner surface of the collector of the light device of the Figure 1 , from the outside along the optical axis. [ Fig 4 ] is a graphical representation of the light image of the illumination beam produced by the light device of the Figure 1 . [ Fig 5 ] is a schematic representation of a light device according to a variant of the first embodiment of the invention. [ Fig 6 ] is a graphical representation of the light image of the illumination beam produced by the light device of the Figure 5 . [ Fig 7 ] is a schematic representation of a light device according to a second embodiment of the invention. [ Fig 8] is a schematic representation of a light device according to a variant of the second embodiment of the invention. Detailed description

[0030] In the following description, the concepts of "above" and "below" the optical axis of the light device are to be understood when the light device is in the functional position, that is to say with an orientation which corresponds to that for which it was designed. Similarly, the concepts "front" and "back" are to be understood according to the general direction of the light, along the optical axis, when the light device is in the functional position.

[0031] THE figures 1 to 4 illustrate a first embodiment of a light device according to the invention.

[0032] There Figure 1is a schematic representation of the lighting device and its operating principle. The lighting device 2 essentially comprises a light source 4, a collector 6 capable of reflecting the light rays emitted by the light source to form a first light beam 12 along an optical axis 8 of the device, and a projection lens 10 for said beam. Other optical projection systems than the projection lens are conceivable, such as in particular one or more mirrors.

[0033] The light source 4 is advantageously of the semiconductor type, such as in particular a light-emitting diode. The light source 4 emits light rays in a half-space delimited by the main plane of said source, according to the example shown, in a main direction perpendicular to said plane and to the optical axis 8. According to the invention, the main emission direction may be inclined relative to a direction perpendicular to the optical axis by an angle less than or equal to 25°.

[0034] The collector 6 comprises a support 6.1, in the form of a shell or cap, and a reflecting surface 6.2 on the inner face of the support 6.1. The reflecting surface 6.2 is advantageously of an elliptical or parabolic or “free form” type profile. The lighting device 2 also comprises a mirror 7 arranged in the extension of the reflecting surface 6.2 of the collector 6. The mirror 7 comprises a support 7.1 and a flat reflecting surface 7.2 formed on the support 7.1. The latter may be the same as or adjacent to the support 6.1 of the collector. The reflecting surface 6.2 of the collector 6 is advantageously a surface of revolution around an axis parallel to the optical axis 8. Alternatively, it may be a free form surface or a swept surface or an asymmetrical surface. It may also comprise several sectors.The term "parabolic type" generally applies to reflectors whose surface has a single focus, i.e., a zone of convergence of the light rays such that the light rays emitted by a light source placed at this convergence zone are projected a long distance after reflection on the surface. Projected a long distance means that these light rays do not converge towards an area located at least 10 times the dimensions of the reflector. In other words, the reflected rays do not converge towards a convergence zone or, if they converge, this convergence zone is located at a distance greater than or equal to 10 times the dimensions of the reflector. A surface of the parabolic type may therefore have parabolic portions or not. A reflector with such a surface is generally used alone to create a light beam.Alternatively, it can be used as a projection surface associated with an elliptical reflector. In this case, the light source of the parabolic reflector is the convergence zone of the rays reflected by the elliptical reflector.

[0035] The mirror 7, more particularly its flat reflecting surface 7.2, is advantageously parallel to the optical axis 8. It may however be inclined relative to said axis, for example by an angle less than or equal to 10°. If it is inclined, the mirror is advantageously divergent with the optical axis in the main direction of propagation of the light, that is to say from the light source 4 towards the projection lens 10.

[0036] The shell- or cap-shaped collector 6 is advantageously made of materials with good heat resistance, for example glass or synthetic polymers such as polycarbonate PC or polyetherimide PEI.

[0037] The light source 4 is arranged at a focus of the reflecting surface 6.2 of the collector 6 so that its rays are collected and reflected towards the mirror 7. The latter forms a virtual image 6.2 of the reflective surface 6.2 and a virtual image 4 of the light source 4, represented in broken lines at Figure 1 . The optical system 10 projects a light image of the virtual image 6.2 of the reflective surface 6.2 and the virtual image 4of the light source 4. At least a portion of these rays reflected by the mirror 7 has angles of inclination α relative to said axis, in a vertical plane, which are less than or equal to 25°, preferably less than or equal to 10°, so as to be in the so-called Gaussian conditions, making it possible to obtain stigmatism, that is to say sharpness of the projected image. These are advantageously the rays reflected by the rear portion of the reflecting surface 6.2 of the collector 6.

[0038] The projection lens 10 has a first input face 10.1 and an output face 10.2. The lens 10 is said to be thin, for example with a thickness along the optical axis which is less than 7 mm, in particular due to the low lens height and the long focal length thereof. The lens 10 may have a focus 10.3 advantageously located between the virtual light source and the virtual reflective surface. The focus 10.3 in question is advantageously located on an area 6.3 located between the virtual images 6.2 And 4 of the reflective surface 6.2 and the light source 4. In this case the focus can be located on the virtual image 6.2 of the reflecting surface 6.2, axially (i.e. along the optical axis) behind the virtual image 4of the virtual light source 4. It should be noted that it is also possible for this focus to be located at the rear or at the front of the virtual image of the reflective surface 6.2 of the collector 6 provided that it is nearby, preferably less than 10 mm, preferably less than 5 mm.

[0039] It should also be noted that the lens 10 is advantageously of the convergent type symmetrical with respect to the virtual optical axis. 8 (in broken line) located above the optical axis 8 and advantageously passing through the focus 10.3.

[0040] The reflecting surface 6.2 of the collector 6, if it is of the elliptical type, has a second focus located at the front of the lens 10 and at a distance from the optical axis 8. It should be noted that it is also possible for this focus to be located at the rear of the lens and / or on the optical axis, provided that it is close to the lens, so as to reduce the width of the beam at the level of the entrance face of the lens.

[0041] The light source 4 and the collector 6 are advantageously a first light source and a first collector, the device then being able to comprise a second light source 14 and a second collector 16 (shown in broken lines). In this case, the first light source 4 and the first collector 6, forming a first light module, and the second light source 14 and the second collector 16, forming a second light module, are opposite relative to the optical axis 8. More particularly, the first and second light sources 4 and 14 are on opposite faces of a common substrate through which the optical axis 8 passes.

[0042] There Figure 2 is a rear view, in perspective, of a rear part of the collector 6 of the light device 2 of the Figure 1. The shell or cap shape of the support 6.1 can be observed, as well as the fact that the reflective surface 6.2 (not visible) has a rear edge 6.2.1. Given that the support 6.1 and, consequently, the reflective surface 6.2 form a shell that is preferably symmetrical in revolution and delimited by a plane, the plane in question includes the rear edge 6.2.1. This extends in the plane laterally on either side of the axis of revolution. When the reflective surface 6.2 is illuminated by the light source, it is then illuminated over its entire surface, the latter being delimited in particular by the rear edge 6.2.1.

[0043] There Figure 3is a representation of the light intensity at the reflective surface 6.2 of the collector seen from the outside, along the optical axis. It is the projected image of the virtual image of the reflective surface 6.2 of the collector, produced by the mirror 7 ( Figure 1). More specifically, the illumination of the surface, namely the power of the striking electromagnetic radiation per unit area perpendicular to its direction, expressed in W / m 2 < . The dark area covering the majority of the surface corresponds to lower illuminations while the central, lighter area corresponds to higher illuminations. It can be observed that the dark area is clearly delimited by the lower edge 6.2.1. In other words, the illuminated surface 6.2 naturally has a clear lower edge capable of forming a cut in the projected lighting beam imaging this surface and also a strong concentration of light, in a central position at the height of the light source.

[0044] There Figure 4 is a graphical representation of the image projected by the light device of the Figure 1. The horizontal axis H and the vertical axis V intersect at the optical axis of the light device. The curves are isolux, that is to say they correspond to the zones of the light beam 12 which have the same illumination expressed in lux. The curves in the center correspond to a higher level of illumination than at the periphery.

[0045] We can observe at the Figure 4 that the light beam 12 has a lower horizontal cut-off, essentially at the level of the horizontal axis. The cut-off is not perfectly straight; it has a curvature which corresponds to aberrations of the image thus produced. In any case, the horizontal cut-off is produced by the edge 6.2.1 ( Figure 3 ) which is the rear edge ( Figure 2 ) of the reflecting surface 6.2 of the collector 6. For this purpose, the focus 10.3 of the lens 10 ( Figure 1 ) is advantageously located near this edge ( Figure 3) on the virtual reflective surface, i.e. behind the virtual image 4 of the (first) light source 4. It can also be observed that the light beam produced has a significant concentration of light above the horizontal axis H.

[0046] This light beam 12 is thus particularly suitable for performing a “high-beam” type lighting function in addition to a “low-beam” type lighting function.

[0047] There Figure 5 is a schematic representation of a variant of the light device 2 of the first embodiment of the invention, illustrated in Figure 1 . This variant is distinguished from the Figure 1 in that the components of the light device 2' are rotated 180° relative to the optical axis 8, all other things being equal.

[0048] The light beam produced 12' is illustrated in the Figure 6 which is to be compared to the Figure 4 . We can observe a reversal of the light image, namely with a higher horizontal cut-off and a strong concentration of light under and at the level of the horizontal axis. This light beam is particularly suitable for performing a "low-beam" type lighting function.

[0049] There Figure 7 is a schematic view of a light device according to a second embodiment of the invention. The reference numbers of the first embodiment are used to designate identical or corresponding elements, these numbers being increased by 100. Reference is also made to the description of these elements in the context of the first embodiment. Specific numbers between 100 and 200 are used to designate the elements specific to this embodiment.

[0050] This second embodiment differs from the first embodiment in that Figure 1 essentially in that the mirror configured to form a virtual image of the light source and the reflecting surface is arranged differently, namely at the optical axis 108 or at least close to it. The mirror 107 in fact extends along the optical axis 108, the latter being advantageously aligned with the support of the light source 104. The reflecting surface 106.2 of the collector is configured to reflect towards the mirror the rays emitted by the light source 104. These reflected rays correspond to virtual images 106.2 And 104 of the reflective surface 106.2 and the light source 104, shown in broken lines. The light beam produced 112 will then correspond essentially to the light beam 12 of the first embodiment, illustrated in Figure 4 .

[0051] Similar to the first embodiment, the lens 110 may have a focus 110.3 advantageously located between the virtual light source and the virtual reflective surface. The focus 110.3 in question is advantageously located on an area 106.3 located between the virtual image 106.2 of the reflective surface 106.2 and the virtual image 104 of the light source 104. In this case the focus can be located on the virtual image 106.2 of the reflecting surface 106.2, axially (i.e. along the optical axis) behind the virtual image 104 of the light source 104. It should be noted that it is also possible that this focus is located at the rear or at the front of the virtual image 106.2 of the reflective surface 106.2 of the collector 106 provided that it is close, preferably less than 10 mm, preferably less than 5 mm.

[0052] Still similar to the first embodiment, the mirror 107, more particularly its flat reflecting surface 107.2, is advantageously parallel to the optical axis 108. It can however be inclined relative to said axis, for example by an angle less than or equal to 10°.

[0053] Still similar to the first embodiment, the light source 104 and the collector 106 are advantageously a first light source and a first collector, the device then being able to comprise a second light source and a second collector. In this case, the first light source 104 and the first collector 106, on the one hand, and the second light source and the second collector, on the other hand, can be opposite relative to the optical axis 8. Alternatively, they can be arranged side by side.

[0054] There figure 8is a schematic representation of a variant of the light device 102 of the second embodiment of the invention illustrated in Figure 7 . This variant is distinguished from the Figure 7 in that the components of the light device 102' are rotated 180° relative to the optical axis 108, all other things being equal.

[0055] The light beam produced 112' essentially corresponds to the light beam 12' produced by the light device of the Figure 5 and illustrated in the Figure 6 . This is a light image reversed with respect to that of the light beam 112 produced by the light device of the Figure 7 , corresponding essentially to that of the Figure 4, namely with a higher horizontal cut-off and a strong concentration of light under and at the level of the horizontal axis H. This light beam is particularly suitable for performing a “low-beam” type lighting function.

[0056] Generally speaking, the lighting devices that have just been described are particularly interesting in that, by imaging the illuminated reflective surface, they make it possible to produce light beams with a concentration of light at a vertically off-center position. These beams are particularly useful for performing the "low-beam" and "high-beam" functions. In addition, these lighting devices, through the use of a mirror, make it possible to turn the light source and the collector associated with the light source, and thus accommodate space constraints.

Claims

1. Luminous device (2; 102), in particular for a motor vehicle, comprising: - a light source (4; 104) able to emit light rays; - a collector (6; 106) with a reflective surface (6.2; 106.2) configured to collect and reflect the light rays emitted by the light source (4; 104); - an optical system (10; 110) configured to project the light rays coming from the reflective surface (6.2; 106.2) into a light beam (12; 112) along an optical axis of the luminous device (8; 108); the luminous device (2; 102) comprises a mirror (7; 107) configured to form a virtual image (4, 6.2; 104, 106.2) of the light source and of the reflective surface of the collector (6; 106), and the optical system (10; 110) is configured to form an image of said virtual image (4, 6.2; 104, 106.2) characterized in that the reflective surface (6.2; 106.2) of the collector (6; 106) has a rear edge (6.2.1; 106.2.1), the light beam (12; 112) being a beam containing a flat cutoff, said cutoff being an image of said rear edge.

2. Luminous device (2; 102) according to Claim 1, characterized in that the reflective surface (6.2; 106.2) of the collector (6; 106) and the mirror (7; 107) are configured so that the light rays reflected by a rear portion of said reflective surface (6.2; 106.2) are parallel to the optical axis (8, 108) or have, in a vertical plane with respect to said axis, an angle of inclination smaller than or equal to 25°, and preferably smaller than or equal to 10°.

3. Luminous device (2; 102) according to one of Claims 1 and 2, characterized in that the mirror (7; 107) is planar and parallel to the optical axis (8; 108) or is inclined with respect to said optical axis by an angle smaller than 10°.

4. Luminous device (2; 102) according to one of Claims 1 to 3, characterized in that the light source (4; 104) is configured to emit light rays in a main direction that is perpendicular to the optical axis (8; 108) or that is inclined with respect to a direction perpendicular to said optical axis by an angle smaller than 25°.

5. Luminous device (2; 102) according to one of Claims 1 to 4, characterized in that the reflective surface (6.2; 106.2) of the collector (6; 106) has a parabolic or elliptical profile.

6. Luminous device (2) according to one of Claims 1 to 5, characterized in that the mirror (7) forms an extension, toward the optical system (10), of the reflective surface (6.2) of the collector (6).

7. Luminous device (2) according to one of Claims 1 to 6, characterized in that the reflective surface (6.2) of the collector (2) is configured to reflect the light rays emitted by the light source (4) in a main direction that is divergent with the optical axis (8).

8. Luminous device (2) according to Claims 6 and 7, characterized in that the mirror (7) is placed in the extension of the reflective surface (6.2) of the collector (6).

9. Luminous device (102) according to one of Claims 1 to 5, characterized in that the light source (104) is placed on a substrate (118), the mirror (7) being aligned with said substrate (118).

10. Luminous device (102) according to Claim 9, characterized in that the reflective surface (106.2) of the collector (6) is configured to reflect the light rays emitted by the light source (104) in a main direction that is convergent with the optical axis (108), said optical axis passing through the substrate (118).

11. Luminous device (2; 102) according to one of Claims 1 to 10, characterized in that the optical system (10; 110) has a focal point (10.3; 110.3) located in a region located between the virtual image (4; 104) of the light source (4; 104) and the virtual image (6.2; 106.2) of the reflective surface (6.2; 106.2).

12. Luminous device (2; 102) according to Claim 11, characterized in that the focal point (10.3; 110.3) of the optical system (10; 110) is located on the virtual image (6.2; 106.2) of the reflective surface (6.2; 106.2), behind the virtual image (4; 104) of the virtual light source (4; 104) along the optical axis (8; 108).

13. Luminous device (2; 102) according to one of Claims 11 and 12, characterized in that the optical system comprises a lens (10; 110) corresponding to a segment of a convergent lens centred on a virtual optical axis (8; 108) parallel to the optical axis (8; 108) and passing through the focal point (10.3; 110.3) of the optical system.

14. Luminous device (2; 102) according to one of Claims 1 to 13, characterized in that the light source (4; 104) and the collector (6; 106) are located above the optical axis (8; 108) when the luminous device is in functional position, the cutoff of the light beam (12; 112) being a lower cutoff.

15. Luminous device (2'; 102') according to one of Claims 1 to 13, characterized in that the light source (4; 104) and the collector (6; 106) are located below the optical axis (8; 108) when the luminous device is in functional position, the cutoff of the light beam (12'; 112') being an upper cutoff.

16. Luminous device (2) according to one of Claims 1 to 15, characterized in that the light source (4; 104), the collector (6; 106) and the light beam (12; 112) are a first light source, a first collector and a first light beam, respectively, the luminous device comprising a second light source (14) and a second collector (16) with a reflective surface configured to collect and reflect the light rays emitted by the second light source (14), the optical system (10; 110) being configured to project the light rays coming from said reflective surface into a second light beam along an optical axis of the device and corresponding to an image of said reflective surface.

17. Luminous device according to Claim 16, characterized in that the first collector (6; 106) and the first light source (4; 104) are opposite, with respect to the optical axis (8; 108), to the second collector (16) and to the second light source (14), respectively; or the first collector and the first light source, on the one hand, and the second collector and the second light source, on the other hand, are placed side-by-side.