LIGHTING DEVICE WITH HOMOGENEOUS PHOTON DIFFUSION, FOR A VEHICLE

Abstract

A lighting device (ED) equips a vehicle and comprises: - a photon source (SP) generating photons, - a diffusion screen (ED) diffusing the photons it receives so that they perform at least one photometric function, - at least one first optical element (EO1) installed between the photon source (SP) and the diffusion screen (ED) and designed to ensure a first predefined spatial distribution of the generated photons, and - at least one second optical element (EO2) installed between the first optical element (EO1) and the diffusion screen (ED) and designed to ensure internal diffusion of the spatially distributed photons before they reach the diffusion screen (ED). Figure 2

Description

Title of the invention: LIGHTING DEVICE WITH HOMOGENEOUS PHOTON DIFFUSION, FOR A VEHICLE Technical field of the invention

[0001] The invention relates to vehicles comprising at least one lighting device capable of performing at least one photometric function by photon scattering. Prior art

[0002] Certain vehicles, possibly of the motor vehicle type, include, generally in a front end, at least one lighting device comprising a source generating photons and a diffusion screen diffusing the generated photons outwards from the vehicle so that they perform at least one photometric function.

[0003] In this type of vehicle, the lighting system often provides a photometric signaling function such as a daytime running light (or DRL – a photometric signaling function, possibly with variable intensity), or a turn signal. Furthermore, in this type of vehicle, the lighting system may also be part of a multi-function optical unit.

[0004] This type of lighting device generally exhibits homogeneity defects in the light defined by the scattered photons on the outer (or front) face of the diffusion screen. Furthermore, the larger the dimensions (width and height) of the diffusion screen, the greater the number and / or severity of the homogeneity defects become. Typically, it proves difficult, if not impossible, to use a diffusion screen with a height (or thickness) greater than 10 mm (unless one accepts the presence of several (or even numerous) homogeneity defects), which limits the diversity of shapes (and therefore of light signatures) and the diversity of insurable photometric functions. It also proves difficult, if not impossible, to use a diffusion screen with a variable height (or thickness), which also limits the diversity of shapes (and therefore of light signatures) and the diversity of insurable photometric functions.

[0005] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0006] In particular, it proposes for this purpose a lighting device, on the one hand, suitable for equipping a vehicle, and, on the other hand, comprising a photon source suitable for generating photons and a diffusion screen suitable for diffusing the generated photons outwards so that they ensure at least a photometric function.

[0007] This lighting device is characterized by the fact that it also includes:

[0008] - at least one first optical element installed between the photon source and the screen of diffusion, and capable of ensuring an initial predefined spatial distribution of the generated photons, and

[0009] - at least one second optical element installed between the first optical element and the diffusion screen is designed to ensure internal diffusion of spatially distributed photons before they reach the diffusion screen.

[0010] Thanks to the invention, it is possible to significantly reduce, or even eliminate, the number and importance of the defects in homogeneity of the light defined by the photons which are diffused outwards by the diffusion screen, which makes it possible to use a diffusion screen having dimensions (width and height) greater than those of the diffusion screens of the prior art diffusion lighting devices, and / or variable dimensions.

[0011] The lighting device according to the invention may include other features which may be taken separately or in combination, and in particular:

[0012] - it may comprise several first optical elements associated respectively to several sub-parts of the photon source, and several second optical elements associated respectively with these first optical elements;

[0013] - each first optical element can be specific for reflecting the generated photons following a first predefined general direction to ensure the first spatial distribution;

[0014] - each second optical element can be arranged in the form of a lens convergent;

[0015] - in the presence of the last option, the first general direction can be perpendicular to an entrance face of each converging lens;

[0016] - in the presence of at least the first option and one of the second and third options or the last sub-option, it may include a third optical element installed between the second optical elements and the diffusion screen and designed to ensure a second predefined spatial distribution of the scattered photons before they reach the diffusion screen;

[0017] - in the presence of the last sub-option, the third optical element can be arranged in the form of a wall of prisms, each with two facets having different spatial orientations in order to orient the incident scattered photons respectively along different predefined second and third general directions;

[0018] - in the presence of the last sub-option or the last sub-sub-option, each first optical element, each second optical element and the third optical element can be part of a single piece made by molding;

[0019] - in the presence of the last sub-sub-sub-option, the broadcast screen can do part of the one-piece unit.

[0020] The invention also proposes a vehicle, possibly of the automobile type, and comprising at least one lighting device of the type presented above.

[0021] For example, this lighting device can provide at least one daytime running light (or DRL) function. Brief description of the figures

[0022] Other features and advantages of the invention will become apparent from an examination of the detailed description below, and the accompanying drawings (obtained using CAD / CAM (“Computer-Aided Design / Computer-Aided Manufacturing”)), in which:

[0023] [Fig. 1] schematically illustrates, in a perspective view from the front side, an example of an embodiment of a left-hand lighting device according to the invention,

[0024] [Fig.2] schematically illustrates, in another perspective view from the front side, the lighting device of [Fig.1] without its electronic board but with the materialization of its photon source,

[0025] [Fig.3] schematically illustrates, in a side perspective view and partially in cross-section in a vertical and approximately transverse plane, a part of the lighting device of Figures 1 and 2,

[0026] [Fig. 4] schematically illustrates, in a perspective view from the rear and partially in cross-section in a vertical and approximately longitudinal plane, a part of the lighting device of Figures 1 and 2, and

[0027] [Fig.5] schematically illustrates, in a perspective view from the front side and partially in section in a vertical and approximately transverse plane, a part of the lighting device of figures 1 and 2, with the materialization of the actions of the first, second and third optical elements on the photons. Detailed description of the invention

[0028] The invention aims in particular to provide a DE lighting device intended to equip a vehicle and ensuring a homogeneous diffusion of photons on its front (or external) face FV.

[0029] In what follows, it is considered, by way of non-limiting example, that the DE lighting device is intended to be fitted to the front end of a motor vehicle, such as a car. However, the DE lighting device can be fitted to any front or rear end of a vehicle (land, sea (or river), or air).

[0030] Furthermore, in the following, by way of non-limiting example, it is considered that the DE lighting device provides a photometric daytime running light (or DRL) function - a photometric signaling function, (possibly of variable intensity). But the DE lighting device could provide another photometric signaling function, such as a direction change indicator (or flashing light).

[0031] In figures 1 to 5 the direction X is intended to be parallel to the longitudinal direction of the vehicle, which is substantially parallel to the lateral (or longitudinal) sides comprising the side doors, the direction Y is intended to be parallel to the transverse direction of the vehicle, which is perpendicular to the longitudinal direction X, and the direction Z is intended to be parallel to the vertical direction of the vehicle, which is perpendicular to the longitudinal direction X and the transverse direction Y.

[0032] In the preceding and following text, the terms "front" and "rear" are defined with respect to the front end of the vehicle. Consequently, the front part of an element is intended to be located closer to the front end of the vehicle than the rear part of that same element.

[0033] Figures 1 and 2 schematically illustrate an example of an embodiment of a DE lighting device according to the invention intended (here) to be installed in a left part of a front end of a vehicle.

[0034] It should be noted that here the DE lighting device does not include a housing because it is intended to be part of a multi-function optical unit. However, a DE lighting device, according to the invention, may also include a housing when it constitutes an independent optical unit.

[0035] As illustrated at least partially in Figures 1 to 5, a lighting device DE, according to the invention, comprises a photon source SP, at least of the first EO1 and second EO2 optical elements, and a diffusion screen ED.

[0036] The SP photon source is suitable for generating photons to participate in at least one photometric function (here a daytime running light (or DRL) function).

[0037] For example, this SP photon source may include at least one light-emitting diode (or LED). But alternatively, it could include at least one laser diode or a gas laser, for example.

[0038] It should be noted, as illustrated non-limitingly in [Fig. 1], that the lighting device DE may also include an electronic board CE comprising the photon source SP and electronic components and / or circuit(s) enabling the control of the power supply and operation of this photon source SP. Also, for example, this electronic board CE may be a printed circuit board of the PCB type ("Printed Circuit Board").

[0039] The ED diffusion screen is arranged so as to diffuse outwards (at the level of its front face FV) the generated photons so that they ensure at least one (the) photometric function. For this purpose, its front face FV can, for example, include a multiplicity of three-dimensional (or 3D) diffusing elements.

[0040] As illustrated at least partially in Figures 2 to 5, the first optical element EO1 is installed between the photon source SP and the scattering screen ED. Furthermore, the first optical element EO1 is arranged to ensure a predefined initial spatial distribution of the generated photons (from the photon source SP).

[0041] Also as illustrated at least partially in Figures 2 to 5, the (each) second optical element EO2 is installed between the (a) first optical element EO1 and the ED scattering screen. Furthermore, the (each) second optical element EO2 is arranged so as to ensure internal scattering of the spatially distributed photons by the associated (a) first optical element EO1 before they reach the ED scattering screen.

[0042] Thanks to this spatial distribution of photons ensured by the first optical element EO1, combined with this internal diffusion of photons ensured by the second optical element EO2, the number and significance of the homogeneity defects of the light defined by the photons scattered at the front face FV of the ED diffusion screen can be significantly reduced, or even eliminated. As a result, it is now possible to use an ED diffusion screen with dimensions (width and height) greater than those of diffusion screens in prior art diffusion lighting devices. Thus, it becomes possible to use an ED diffusion screen with a height (or thickness) strictly greater than 10 mm, and for example equal to 15 mm, which significantly increases the diversity of shapes (and therefore of light signatures) and the diversity of photometric functions that can be achieved by the DE lighting device.It also becomes possible to use an ED diffusion screen with a variable height (or thickness), which further increases the diversity of shapes (and therefore light signatures) and the diversity of photometric functions that can be ensured by the DE lighting device.

[0043] For example, and as illustrated, without limitation and at least partially, in Figures 2 to 5, the lighting device DE may comprise several first optical elements EO1 associated respectively with several sub-parts of the photon source SP (here, light-emitting diodes), and several second optical elements EO2 associated respectively with these first optical elements EO1. It should be noted that in the example illustrated, without limitation, in Figures 2 and 3, the number of first optical elements EO1 (and therefore of sub-parts of the photon source SP or of second optical elements EO2) is eight. However, this number may take any value greater than or equal to one.

[0044] Also, for example, and as illustrated, but not limited to, in [Fig. 5], each first optical element EO1 can be designed to reflect the generated photons (here by the associated sub-part of the photon source SP) along a predefined general direction dl to ensure the initial spatial distribution. To this end, each first optical element EO1 can be arranged as a block above which the associated sub-part of the photon source SP is installed, and having internal faces arranged to ensure internal reflections of the photons, orienting them all along this first general direction dl.

[0045] It should be noted that in the preceding and following, "general direction" means a preferred direction of propagation of photons (and therefore the photons may have directions of propagation very slightly different from this general direction).

[0046] But other arrangements of each first optical element EO1 can be envisaged so as to ensure other first spatial distributions compatible with the homogeneity sought at the output of the front face FV of the diffusion screen ED.

[0047] Also, for example, and as illustrated, but not limited to, in Figures 2 to 5, each second optical element EO2 can be arranged in the form of a converging lens. It will be understood from observing [Fig. 5] that the focal length of each converging lens EO2 is small so as to induce, downstream of the focal point, a significant divergence (and therefore internal scattering) of the photons propagating towards the scattering screen ED.

[0048] But other arrangements of each second optical element EO2 can be envisaged so as to ensure other types of internal diffusion compatible with the desired homogeneity at the output of the front face FV of the ED diffusion screen. For example, each second optical element EO2 could be arranged in the form of a diverging lens.

[0049] Also, for example, and as illustrated non-limitingly in [Fig. 5], the first general direction dl can be perpendicular to the entrance (or rear) face FE of each converging lens EO2. But this is not mandatory.

[0050] Also, for example, and as illustrated without limitation in Figures 2 to 5, the lighting device DE may also include a third optical element EO3 installed between the second optical elements EO2 and the diffusion screen ED. In this case, this third optical element EO3 is arranged so as to ensure a second predefined spatial distribution of the photons scattered by the (each) second optical element EO2 before they reach the diffusion screen ED.

[0051] This second spatial distribution, ensured by the third optical element EO3, advantageously allows for a further reduction in the number and significance of defects. of homogeneity of light defined by the photons which are scattered at the level of the front face FV of the ED diffusion screen, and therefore to use an ED diffusion screen having dimensions (width and height) even larger than those of the diffusion screens of prior art diffusion lighting devices, and / or variable dimensions.

[0052] Also, for example, and as illustrated, without limitation and at least partially, in Figures 1 to 5, the third optical element EO3 can be arranged in the form of a prism wall, each prism having two facets. These facets have different spatial orientations in order to orient the incident scattered photons respectively along different predefined second d2 and third d3 general directions, to ensure the second predefined spatial distribution of the photons before they reach the scattering screen ED.

[0053] But other arrangements of the third optical element EO3 can be envisaged so as to ensure other second spatial distributions compatible with the homogeneity sought at the output of the front face FV of the diffusion screen ED.

[0054] Also, for example, and as illustrated, without limitation and at least partially, in Figures 1 to 5, each first optical element EO1, each second optical element EO2, and the third optical element EO3 can advantageously be part of a single-piece component PM made by molding a rigid material that is transparent to the photons generated by the photon source SP. This makes it possible to significantly reduce the number of parts that need to be assembled to constitute the lighting device DE, and therefore to reduce its cost and size. However, this is not mandatory.

[0055] For example, the material in which the PM one-piece part is made can be polycarbonate (or PC), and in particular PC “TARFLON” (registered trademark) which promotes the diffusion of photons.

[0056] Also, for example, and as illustrated, but not limited to, and at least partially, in Figures 1 and 2, the diffusion screen ED can also be part of the single-piece component PM. This further reduces the number of parts that need to be assembled to form the lighting device DE, and therefore further reduces its cost and size. However, this is not mandatory.

Claims

Demands

1. Lighting device (ED) suitable for equipping a vehicle and comprising a photon source (SP) suitable for generating photons and a diffusion screen (ED) suitable for diffusing said generated photons outwards so that they perform at least one photometric function, characterized in that it further comprises i) at least one first optical element (EO1) installed between said photon source (SP) and said diffusion screen (ED) and suitable for ensuring a first predefined spatial distribution of said generated photons, and ii) at least one second optical element (EO2) installed between said first optical element (EO1) and said diffusion screen (ED) and suitable for ensuring an internal diffusion of the spatially distributed photons before they reach said diffusion screen (ED).

2. Lighting device according to claim 1, characterized in that it comprises several first optical elements (EO1) associated respectively with several sub-parts of said photon source (SP), and several second optical elements (EO2) associated respectively with said first optical elements (EO1).

3. Lighting device according to claim 1 or 2, characterized in that each first optical element (EO1) is suitable for reflecting said generated photons along a first predefined general direction to ensure said first spatial distribution.

4. Lighting device according to any one of claims 1 to 3, characterized in that each second optical element (EO2) is arranged in the form of a converging lens.

5. Lighting device according to claim 4, characterized in that said first general direction is perpendicular to an entrance face (FE) of each converging lens (EO2).

6. Lighting device according to claim 2 taken in combination with any one of claims 3 to 5, characterized in that it comprises a third optical element (EO3) installed between said second optical elements (EO2) and said diffusion screen (ED) and adapted to ensure a second predefined spatial distribution of said diffused photons before they reach said diffusion screen (ED).

7. Lighting device according to claim 6, characterized in that said third optical element (EO3) is arranged in the form of a wall of prisms each having two facets having different spatial orientations in order to orient said incident scattered photons respectively along different predefined second and third general directions.

8. Lighting device according to claim 6 or 7, characterized in that each first optical element (EO1), each second optical element (EO2) and said third optical element (EO3) are part of a single piece (PM) made by molding.

9. Lighting device according to claim 8, characterized in that said diffusion screen (ED) is part of said one-piece (PM).

10. Vehicle, characterized in that it comprises at least one lighting device (ED) according to any one of claims 1 to 9.

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