LIGHTING DEVICE WITH LONG LIGHT GUIDE(S) AND SUITABLE FOR RECEIVING HIGH LIGHT POWER

Abstract

A lighting device (DE) comprises an elongated light guide (GL1) suitable for receiving photons generated on an end face (FE) and for delivering the photons received on a lateral face after internal reflections to ensure a photometric function, and a photon source (SP1) placed in front of the end face (FE) and comprising a first number of light diodes (DL1-DL7), generating the photons, depending on a chosen light power. The light guide (GL1) comprises a first part (P1) comprising the end face (FE) and having a generally circular cross-section with a second number of protrusions (E1-E6) depending on the first number, so as to allow the placement of each light diode (DL1-DL7) in front of the end face (FE). Figure 4

Description

Title of the invention: LIGHTING DEVICE WITH LONG LIGHT GUIDE(S) AND SUITABLE FOR RECEIVING HIGH LIGHT POWER Technical field of the invention

[0001] The invention relates to lighting devices with elongated light guide(s). State of the art

[0002] In certain technical fields, such as for example in certain vehicles, possibly of the automobile type, lighting devices are used which comprise at least one elongated light guide and at least one photon source. The (each) light guide is capable of receiving photons generated on an end face and of delivering the photons received on a lateral face after internal reflections, to ensure a photometric function. The (each) photon source is placed in front of this end face and capable of generating the photons.

[0003] For example, in a motor vehicle the lighting device may be fixedly secured to a grille installed in the front end.

[0004] Also for example, in a motor vehicle the photometric function can be a daytime running light function (or DRL (“Daytime Running Light (or Lamp)”) - photometric signaling function).

[0005] As is known to those skilled in the art, when the length of a light guide becomes relatively large, typically greater than 30 cm, it is no longer capable of delivering the photons, which it receives on its end face, uniformly over the entire length of its lateral face. This results from the fact that its diameter is hardly greater than 10 mm and therefore that the surface area (generally circular) of its end face is relatively small, which only allows a single light diode to be placed in front of this end face (at a very short distance). It will be understood in fact that the photons delivered by a light diode are received at the end face in a coverage area having a surface area which is much greater than that occupied by this light diode.Therefore, if several light diodes are placed in front of this end face, some of the delivered photons will pass by the latter and therefore produce stray light which is lost and above all annoying and induces unwanted heating.

[0006] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0007] For this purpose, it proposes in particular a lighting device comprising:

[0008] - at least one elongated light guide suitable for receiving generated photons on an end face and to deliver the received photons on a side face after internal reflections to ensure a photometric function, and

[0009] - at least one photon source placed in front of the end face and suitable for generate the photons.

[0010] This lighting device is characterized by the fact:

[0011] - that the (each) photon source comprises a first number of diodes read miners depending on a chosen light power, and

[0012] - that the (each) light guide comprises a first part comprising its face end and having a generally circular cross-section with a second number of protrusions depending on the first number, so as to allow placement of each light diode in front of the end face.

[0013] Thanks to the invention, it is now possible to place several light diodes in front of the end face and therefore to supply the latter with a high light power which makes it possible to use very long light guides capable of delivering the received photons homogeneously over the entire length of their lateral face.

[0014] The lighting device according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0015] - it can comprise two light guides associated respectively with two sources of photons;

[0016] - each light guide may comprise a second part extending its first part and a third part extending the second part and comprising the lateral face. In this case, its second part may have a generally circular cross-section and may be suitable for guiding the photons from the first part to the third part;

[0017] - the second number can be between two and six, and the first number can be between three and seven.

[0018] - each light diode may be a light-emitting diode;

[0019] - the photometric function can be a daytime running light (or DRL) function.

[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 vehicle may comprise a front end comprising a grille to which the lighting device is fixedly secured. In this case, the vehicle may comprise two lighting devices, right and left, secured respectively to right and left parts of the grille. Brief description of the figures

[0022] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the attached drawings (mostly obtained in CAD / CAM (“Computer Aided Design / Computer Aided Drawing”)), on which:

[0023] [Fig.l] schematically illustrates, in a perspective view from the front side, an example of a front end of a vehicle comprising a grille equipped with two exemplary embodiments of a lighting device according to the invention,

[0024] [Fig.2] schematically illustrates, in a side perspective view, a part of an exemplary embodiment of a lighting device according to the invention, before it is fitted to a vehicle grille,

[0025] [Fig.3] schematically illustrates, in a perspective view from the rear side, the first parts of the two light guides of the lighting device of [Fig.2], and

[0026] [Fig.4] schematically illustrates, in a front view from the rear side, the face end of the first light guide of the lighting device of [Fig.2], with the materializations of the positions of the light diodes of the associated photon source and the coverage areas of most of these light diodes. Detailed description of the invention

[0027] The invention aims in particular to propose a lighting device DE comprising at least one elongated light guide GLj, of great length and adapted to the reception of a high luminous power on its end (rear) face FE receiving the photons generated by an associated photon source SPj.

[0028] In the following, it is considered, by way of non-limiting example, that the lighting device DE is intended to equip a vehicle of the automobile type, such as for example a car. But the lighting device DE can equip any vehicle (land, sea (or river), or air), any electrical appliance, any installation (including industrial), and any building (public or private) which must (or can) include a lighting device DE comprising at least one elongated light guide.

[0029] Furthermore, it is considered in the following, by way of non-limiting example and as illustrated non-limitingly in [Fig. 1], that the lighting device DE is intended to equip a grille CV installed in the front end EV of a motor vehicle. But the lighting device DE could be intended to equip the rear end of a motor vehicle, for example.

[0030] It will be noted that in the example illustrated non-limitingly in [Fig.l] two lighting devices DE, right and left, are fixedly secured and respectively to right and left parts of the grille CV. But only one lighting device DE could be fixedly secured to the grille CV.

[0031] Furthermore, the following is considered, by way of non-limiting example and as illustrated non-limitingly in [Fig.l], that the lighting device DE is intended to provide a photometric signaling function, and more precisely a daytime running light (or DRL) function. But it could provide another photometric signaling function or a photometric lighting function or even a photometric lighting effect function (possibly decorative).

[0032] In the above and the following, the notion of "front" is defined in relation to the place where the photons participating in the photometric function exit, and the notion of "rear" is defined in relation to the place which is opposite to that where the photons participating in the photometric function exit. Consequently, the front face of an element is oriented towards the outside, while the rear face of this element is oriented towards the inside and opposite the front face.

[0033] [Fig.l] schematically illustrates an example of a front end EV of a vehicle comprising a grille CV comprising right and left parts to which are respectively fixedly secured, for example by clipping and / or screwing, two lighting devices DE, right and left, according to the invention.

[0034] As illustrated at least partially in Figures 2 to 4, a lighting device DE, according to the invention, comprises at least one photon source SPj and at least one light guide GLj, as well as possibly a protective glass and / or a housing at least partially housing the photon source(s) SPj and light guide(s) GLj.

[0035] It will be noted that in the example illustrated non-limitingly and at least partially in Figures 2 and 3, the lighting device DE comprises two light guides GL1 (j = 1) and GL2 (j = 2), associated respectively with two photon sources SPj (only the first photon source SP1 is illustrated in Figures 2 and 4). But the number of light guides GLj, and therefore also the number of light sources SPj, can take any value greater than or equal to one.

[0036] As illustrated in [Fig.2], the (each) light guide GLj is elongated and suitable for receiving photons generated on an end (rear) face FE forming part of a first part PI, and for delivering the photons received on a lateral face FL after internal reflections, to ensure a photometric function (here a daytime running light function).

[0037] As appears at least partially in Figures 2 and 4, the (each) photon source SPj is placed in front of the end face FE of the first part PI of the associated light guide GLj, and is capable of generating the photons intended for this end face FE. In addition, the (each) photon source SPj comprises a first number ni of light diodes DLm which is a function of the chosen light power to be received by the end face FE of the first part PI of the associated light guide GLj.

[0038] For example, and as illustrated non-limitingly in [Fig.2], each source of SPj photons (and its control and power supply means) can be installed on a front face of a CE electronic card, facing each FE end (rear) face. Also, for example, the CE electronic card can be a PCB type printed circuit board ("Printed Circuit Board").

[0039] As illustrated in Figures 3 and 4, the first part PI of each light guide GLj has a generally circular cross-section with a second number n2 of protrusions (or lobes) Ek which is a function of the first number ni. This particular arrangement of each first part PI allows placement of each of the ni light diodes DLm in front of the end face FE, with a very reduced number, or even zero, of delivered photons passing next to the latter (FE).

[0040] Thus, thanks to the protrusion(s) (or lobe(s)) Ek of the transverse section of the first part PI, it is now possible to place several light diodes DLm in front of the end face FE because the stray light lost is very low, or even zero, and therefore does not risk constituting a nuisance or inducing undesirable heating. Consequently, the light power received by an end face FE can now be significant and therefore make it possible to use light guides GLj of great length, typically greater than 30 cm (and for example equal to 45 cm or 50 cm), and capable of delivering the received photons homogeneously over the entire length of their lateral face FL.

[0041] It will be understood in fact that the protrusions Ek make it possible to increase the surface area of ​​the end face FE in order to contain the coverage zones ZC of the light diodes DLm (i.e. the zones of the end face FE in which (statistically) they send the photons that they generate respectively). In other words, the photons that would be lost in the presence of a circular end face are now received by an end face FE with a circular main part increased by protrusion(s) Ek.

[0042] For example, the circular main portion of an FE end face may have a diameter between 8 mm and 10 mm.

[0043] Also for example, and as illustrated non-limitingly in [Fig. 2], each light guide GLj may comprise a second part P2 which extends its first part PI, and a third part P3 which extends the second part P2 and which comprises the lateral face FL. In this case, the second part P2 may have a transverse section of generally circular shape, and may be suitable for guiding the photons coming from the first part PI to the third part P3 which extends it.

[0044] Also for example, the second number n2 can be between two and six. It will be noted that in the example illustrated non-limitingly in Figures 3 and 4 the second number n2 is equal to six, and therefore there are six outgrowths (or lobes) E1 to E6 (k = 1 to 6), spaced two by two at an angle of 30°. But the second number n2 can take any value greater than or equal to one, it depends on the first number of LEDs DLm to be placed in front of an end face FE.

[0045] Also for example, the first number ni can be between three and seven. It will be noted that in the example illustrated non-limitingly in [Fig.4] the first number ni is equal to seven, and therefore there are seven light diodes DL1 to DL7 (m = 1 to 7). But the first number ni can take any value greater than or equal to two, this depends on the light power that an end face FE must receive.

[0046] Also for example, each light diode DLm can be a light-emitting diode (or LED), possibly organic (or OLED). But as a variant each light diode DLm could be a laser diode, for example.

[0047] Also for example, each light guide GLj can be made by molding a rigid plastic or synthetic material, such as for example polycarbonate (or PC)

Claims

Claims

1. Lighting device (DE) comprising i) at least one elongate light guide (GLj) suitable for receiving photons generated on an end face (FE) and for delivering said photons received on a lateral face (FL) after internal reflections, to ensure a photometric function, and ii) at least one photon source (SPj) placed in front of said end face (FE) and suitable for generating said photons, characterized in that said photon source (SPj) comprises a first number of light diodes (DLm) depending on a chosen light power, and in that said light guide (GLj) comprises a first part (PI) comprising said end face (FE) and having a generally circular cross-section with a second number of protrusions (Ek) depending on said first number, so as to allow placement of each light diode (DLm) in front of said end face (FE).

2. Lighting device according to claim 1, characterized in that it comprises two light guides (GLj) associated respectively with two photon sources (SPj).

3. Lighting device according to claim 1 or 2, characterized in that each light guide (GLj) comprises a second part (P2) extending said first part (PI) and a third part (P3) extending said second part (P2) and comprising said lateral face (FL), said second part (P2) having a generally circular cross-section and being capable of guiding said photons from said first part (PI) to said third part (P3).

4. Lighting device according to one of claims 1 to 3, characterized in that said second number is between two and six, and in that said first number is between three and seven.

5. Lighting device according to one of claims 1 to 4, characterized in that each light diode (DLm) is a light-emitting diode.

6. Lighting device according to one of claims 1 to 5, characterized in that said photometric function is a daytime running light function.

7. Vehicle, characterized in that it comprises at least one lighting device (DE) according to one of claims 1 to 6.

8. Vehicle according to claim 7, characterized in that it comprises a front end (EV) comprising a grille (CV) to which is so- fixedly lidarized said lighting device (DE).

9. Vehicle according to claim 8, characterized in that it comprises two lighting devices (DE), right and left, secured respectively to right and left parts of said grille (CV).

10. Vehicle according to one of claims 7 to 9, characterized in that it is of the automobile type.

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