Lighting and / or signaling device and optical unit for a motor vehicle comprising this device

Description

[0001] The present invention relates to a lighting and / or signaling device, particularly for motor vehicles, and an optical unit comprising said device. It is specifically intended for position lights and / or daytime running lights, turn signals, or brake lights.

[0002] In this area, manufacturers want to stand out, particularly with visually original elements, in order to be more easily identifiable compared to competitors.

[0003] Recent technologies have been developed, featuring devices equipped with a light source, generally a light-emitting diode (LED), and a light guide through which a beam of light from the source propagates. The light travels through the guide by total internal reflection to an output face, which projects the light so that it can be seen by vehicles following or preceding it.

[0004] In the automotive field, such devices are appreciated because they allow for a wide variety of shapes and types of light, combining original design, notable compactness, and luminous efficiency.

[0005] On the other hand, it is possible to mount several guides of this type within the same optical block. However, these guides will have different lengths when mounted in an optical block with an unusual curvature.

[0006] When several light guides, mounted in the same optical block, have different lengths, the brightness emitted by each varies relative to the others. Light guides are commonly made of a material that absorbs some of the light they transmit. The amount of light emitted therefore depends on the thickness of the material through which it passes.

[0007] This results in a lack of homogeneity between the light propagated to the exit faces of the different light guides mounted within the same optical block, and having different lengths.

[0008] Therefore, any car manufacturer wishing to combine multiple light guides within a single optical unit must ensure that the light output from each guide is uniform. Otherwise, the result will be aesthetically displeasing to users, especially when the light guides transmit light of different colors and / or intensities.

[0009] Document EP 2 476 947 A2 describes an optical block according to the preamble of claims 1 to 4.

[0010] The invention aims to homogenize the luminous flux transmitted by several optical guides, within the same optical block, in particular when these optical guides have different lengths.

[0011] The invention relates to an optical block comprising a lighting and / or signaling device, according to any one of independent claims 1 to 4. The dependent claims describe particular embodiments.

[0012] For this purpose, the lighting and / or signaling device of the invention, in particular for motor vehicles, comprises at least two light flux sources and at least two optical light flux guides having a different longitudinal extension from each other, and located so that each of said sources emits its light flux into one of said optical guides, said optical guides being made of a material capable of absorbing part of the light flux it transmits, said device being configured to correct an intensity of the light fluxes at the output of said optical guides.

[0013] Using a correction of the intensity of the emitted fluxes, to homogenize the luminous fluxes transmitted by the different optical guides of said fluxes within the same optical block, makes it possible to homogenize the rendered appearance.

[0014] According to different embodiments of the invention, which may be considered together or separately: said light sources and / or optical guides are configured to correct the intensity of the light fluxes at the output of said optical guides; said optical guides have an input face, located such that each of said sources emits its light flux into one of said input faces, and an output face of a light flux transmitted along said optical guides; said output face and said input face being separated from each other by a distance corresponding to the respective longitudinal extension of said optical guides; the device of the invention comprises a plurality of identical light sources; said light sources comprising a correction means capable of adapting the amount of current supplied to light-generating means for each of said sources; said device comprises a common support means for said sources, preferably planar.said luminous flux sources are positioned on an electrical circuit whose surface is preferably flat; said device includes a means for controlling the amount of current supplied to said sources; said control means is capable of reducing the amount of current supplied to some of the luminous flux sources and / or increasing the amount of current supplied to others, so that two adjacent sources do not emit the same luminous flux; said control means is configured so that two adjacent luminous flux sources do not receive the same amount of current, and that, progressively, the amount of current supplied decreases from the source opposite the longest optical guide to the source opposite the shortest optical guide; said control means is configured so that two adjacent luminous flux sources do not receive the same amount of current, and that, progressively,The quantity of current supplied increases from the source opposite the shortest optical guide to the source opposite the longest optical guide. The control means comprises one or more different resistors, said resistor(s) being capable of dissipating a portion of the supply current from at least one of said light sources. The device of the invention comprises a plurality of different light sources, such that the luminous flux they emit is different. The light sources comprise one or more light-emitting diodes. The device of the invention comprises a correction means adapted to at least a portion of at least one of the light-fluid optical guides, said correction means being configured to absorb light such that the optical guide(s) receiving said correction means transmit a reduced quantity of luminous flux.Compared to the same optical guides without said correction means, said correction means takes the form of an addition of material capable of absorbing a portion of the light flux passing through it, said material being injected into at least a portion of at least one of said optical guides, said material is injected at the ends opposite the light sources, said material injected into at least a portion of at least one of the optical guides is identical, or different for each of said optical guides into which said material(s) are injected, the device of the invention is configured such that each of the optical light flux guides, positioned opposite one of said sources, is defocused from said source, along a longitudinal axis of said optical guide, and / or along an axis perpendicular to said longitudinal axis, the optical light flux guides take the form of light guides made of plastic or glass material.

[0015] The invention relates to an optical unit for a motor vehicle, comprising a device as described above.

[0016] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent in the course of the detailed explanatory description which will follow, of at least one embodiment of the invention given by way of purely illustrative and non-limiting example, with reference to the attached schematic drawings.

[0017] In these drawings: there figure 1 shows a schematic view of an example embodiment of an optical block according to the invention, said optical block comprising light sources positioned on a common support, and optical guides for said light of different lengths, the figure 2 presents a control means capable of supplying current to light generators that are the source of the luminous flux emitted by the light sources, the figure 3 presents means of controlling the lighting and / or signaling device of the optical unit of the figure 1 , according to one embodiment of the invention, the figure 4 shows the optical block shown on the figure 1 , according to another embodiment of the invention, the figure 5 shows the optical block shown on the figure 1 , according to yet another embodiment of the invention, the figure 6 shows the optical block shown on the figure 1 , according to yet another embodiment of the invention,

[0018] There figure 1 This shows a schematic view of an optical block 10, according to the invention, the curve of which here presents a curved portion 12 and a flat portion 14. Said optical block 10 comprises light sources 1-6 with luminous flux F1-F6 and optical guides T1-T6 of said flux F1-F6. These optical guides T1-T6 have different lengths L1-L6. For the sake of clarity, only the luminous fluxes F1 and F6 are shown; similarly, only the lengths L1 and L6 are indicated.

[0019] The light sources 1-6, with luminous flux F1-F6, are advantageously positioned on a common, flat support 16. This support 16 is, for example, a printed circuit board, in particular an insulated metallic substrate, or any other means of supplying current to several light generators.

[0020] The optical guides T1-T6 with luminous flux F1-F6 are each capable of transmitting a luminous flux F1-F6 by total internal reflection as it propagates along its longitudinal axis. These optical guides T1-T6 have an entrance face, into which each of the sources 1-6 emits its luminous flux F1-F6, and an exit face located at a distance L1-L6 from the entrance face. These optical guides T1-T6 are made of a material capable of absorbing a portion of the luminous flux F1-F6 that they transmit. This material can be plastic—for example, polymethyl methacrylate (PMMA) or polycarbonate (PC)—or any other material exhibiting reflective properties. In the example shown in the figure 1 , the T1-T6 optical guides absorb on the order of 1 to 5% of the F1-F6 luminous flux for approximately 10mm of material traversed.

[0021] On the other hand, the figure 1 represents an optical block 10 in which the optical guides T1-T6 have a length L1-L6 that gradually increases from L1 to L6 from optical guide T1 to the middle T6. More precisely, the path length traveled by a light flux F1 in optical guide T1 is D1 and the path length traveled by a light flux F6 in optical guide T6 is D6. The difference in length between L1 and L6, and a fortiori between D1 and D6, can be on the order of 100 mm in the case of a pronounced curve 12 such as that shown in the figure 1 .

[0022] The said sources 1-6 each comprise one or more light generators associated, or not, with a reflector, or even with any other optical element. The preferred light generator of the invention is a light-emitting diode.

[0023] There figure 2 This diagram presents a control means capable of supplying current to diodes 1'-6', which are the source of the luminous fluxes F1-F6 emitted by the luminous flux sources 1-6. This control means is an integrated electrical circuit, as mentioned above, mounted on a printed circuit board. In the example configuration, the six diodes 1'-6' are grouped into two branches of three diodes. They are powered by a current generator 20.

[0024] If all diodes carry the same current and emit the same luminous flux, assuming they are of the same type, then approximately a 40% difference can be observed between a luminous flux F6 transmitted by the longest optical guide T6 and a luminous flux F1 transmitted by the shortest optical guide T1. This is due to the phenomenon described above: the absorption of the luminous fluxes F1-F6 by the material of the optical guides T1-T6. The consequence is a decrease in the luminous flux emitted at the output of the longest optical guide T6 compared to that emitted at the output of the shortest optical guide T1.

[0025] Therefore, the device of the invention is configured to correct the intensity of the luminous flux F1-F6 at the output of said optical guides T1-T6.

[0026] This can involve, among other embodiments, using different types of diodes, and / or adapting the control of each diode 1'-6' so that the input flux of each optical guide T1-T6 is such that the output fluxes of said means T1-T6 are identical. It is then possible to obtain identical brightness at the output of all the optical guides T1-T6.

[0027] Thus, a first embodiment of the invention consists of progressively reducing the current in each diode by going from diode 6' to diode 1' (embody not illustrated).

[0028] A second embodiment of the invention consists of progressively increasing the current in each diode by going from diode 1' to diode 6' (embody not illustrated).

[0029] A third embodiment of the invention consists of increasing the current in some diodes and reducing it in others (embody not illustrated).

[0030] A fourth embodiment, as already mentioned, consists of choosing 1'-6' diodes that are different from each other, so that the luminous fluxes emitted by the 1'-6' flux sources comprising these 1'-6' diodes are different. This embodiment is illustrated in the figure 2 .

[0031] There figure 3 This illustrates a fifth embodiment. In parallel with each diode 1'-6', a resistor R1-R6 is connected, its value varying. It is lowest for resistor R1 and increases progressively up to resistor R6. Thus, the proportion of current diverted through the resistor is higher for resistor R1 than for resistor R6. Consequently, the amount of current flowing through diode 1' is lower than through diode 6'. Diode 6' therefore emits more light than diode 1'. The resistor R6 can even be infinite. Thus, the current flowing through diode 6' is high, and the overall efficiency of the optical block is optimized. If diodes 1'-6' are different, the resistors R1-R6 can be adjusted accordingly.

[0032] It is also possible to correct the intensity of the luminous fluxes F1-F6 at the optical guides T1-T6. The aim remains the homogenization of the luminous fluxes transmitted F1-F6 by several optical guides T1-T6 of different lengths L1-L6, within an optical block 10.

[0033] Thus, the figure 4 This presents a sixth embodiment of the invention. An absorbing material M1-M6 is injected into the optical guides T1-T6, said absorbing material being configured to absorb light such that, when optical guides T1-T6 receive said material M1-M6, they transmit a reduced amount of luminous flux. This absorbing material M1-M6 is injected over an increasingly large thickness Z1-Z6, from the longest optical guide T6 to the shortest optical guide T1. This results in identical luminous fluxes at the output of the optical guides T1-T6. Advantageously, the thickness Z6 of the material M6 is zero. The overall efficiency of the optical block is thus optimized.

[0034] There figure 5 This presents a seventh embodiment of the invention. An absorbent material M1-M6 is injected, but at varying densities: the injected material M1-M6 exhibits increasingly greater absorption from the flux source 6 to the flux source 1. The absorption differences between the optical guides T1-T6 thus obtained can also be achieved by using dyes or by injecting different materials M1-M6. Advantageously, the material M6 is identical to the material used for the optical guides. This optimizes the overall efficiency of the optical block.

[0035] For the sixth and seventh embodiments, the absorbing zone M1-M6 can be located at other points on the optical guides T1-T6, rather than at the ends opposite the light sources 1-6, as shown in the figures 4 And 5It is also conceivable that these absorbing zones M1-M6 cover the entirety of the optical guides T1-T6.

[0036] There figure 6 presents an eighth embodiment of the invention. The sources are represented progressively defocused along a longitudinal axis of said optical guide, moving away from the source, by a distance J1 to J6. They can also be represented along an axis perpendicular to said longitudinal axis axially, by progressively decentering.

[0037] This also allows for identical light fluxes at the output of optical guides T1-T6, for example when diodes 1'-6' are identical and the corresponding sources 1-6 emit the same light flux.

[0038] It should be noted that alternative embodiments are of course possible. In particular, it is also conceivable, in an additional embodiment, that the homogenization of the transmitted luminous flux F1-F6, by several optical guides T1-T6, within an optical block 10, is achieved by modifying the coupling surfaces between flux sources 1-6 and associated optical guides T1-T6.

[0039] Light flow T1-T6 optical guides are, for example, in the form of light guides, preferably made of plastic. They may be in the form of a cord, in which case the entrance and exit faces will be located at opposite longitudinal ends of the cord. Alternatively, they may be in the form of a plate, in which case the entrance and exit faces will be located at two opposite edges of the plate.

[0040] It is entirely possible to combine the implementation methods presented above in order to optimize the expected result.

[0041] Regardless of the embodiment, the invention just described will find a preferred application in the optical blocks of motor vehicles having an original curvature, in which the light is emitted by light guides of different lengths.

Claims

1. Optical unit, particularly for a motor vehicle, comprising a lighting and / or signaling device comprising at least two sources (1-6) of luminous flux (F1-F6) and at least two optical guides (T1-T6) of luminous flux (F1-F6) having different longitudinal extensions from one another, and located so that each of said sources (1-6) emits its luminous flux (F1-F6) into one of said optical guides (T1-T6), said optical guides (T1-T6) being made of a material capable of absorbing part of the luminous flux (F1-F6) it transmits, said device being configured to correct an intensity of the luminous fluxes (F1-F6) at the output of said optical guides (T1-T6), the use of the correction of the intensity of the emitted fluxes, to homogenize the luminous fluxes transmitted by the different optical guides (T1-T6) of said fluxes within said optical unit (10), allowing to homogenize the rendered appearance, characterized in that the optical unit comprises a plurality of identical sources (1-6) of luminous flux (F1-F6), and wherein said sources (1-6) of luminous flux (F1-F6) comprise a correction means capable of adapting the amount of current supplied to light generating means (1'-6') of each of said sources (1-6), so that the input flux of each optical guide (T1-T6) is such that the output fluxes of said guides (T1-T6) are identical.

2. Optical unit, particularly for a motor vehicle, comprising a lighting and / or signaling device comprising at least two sources (1-6) of luminous flux (F1-F6) and at least two optical guides (T1-T6) of luminous flux (F1-F6) having different longitudinal extensions from one another, and located so that each of said sources (1-6) emits its luminous flux (F1-F6) into one of said optical guides (T1-T6), said optical guides (T1-T6) being made of a material capable of absorbing part of the luminous flux (F1-F6) it transmits, said device being configured to correct an intensity of the luminous fluxes (F1-F6) at the output of said optical guides (T1-T6), the use of the correction of the intensity of the emitted fluxes, to homogenize the luminous fluxes transmitted by the different optical guides (T1-T6) of said fluxes within said optical unit (10), allowing to homogenize the rendered appearance, characterized in that the optical unit comprises a plurality of different sources (1-6) of luminous flux (F1-F6), so that the luminous flux (F1-F6) they emit is different, so that the input flux of each optical guide (T1-T6) is such that the output fluxes of said guides (T1-T6) are identical.

3. Optical unit, particularly for a motor vehicle, comprising a lighting and / or signaling device comprising at least two sources (1-6) of luminous flux (F1-F6) and at least two optical guides (T1-T6) of luminous flux (F1-F6) having different longitudinal extensions from one another, and located so that each of said sources (1-6) emits its luminous flux (F1-F6) into one of said optical guides (T1-T6), said optical guides (T1-T6) being made of a material capable of absorbing part of the luminous flux (F1-F6) it transmits, said device being configured to correct an intensity of the luminous fluxes (F1-F6) at the output of said optical guides (T1-T6), the use of the correction of the intensity of the emitted fluxes, to homogenize the luminous fluxes transmitted by the different optical guides (T1-T6) of said fluxes within said optical unit (10), allowing to homogenize the rendered appearance, characterized in that the optical unit comprises a correction means adapted to at least a part of at least one of the optical guides (T1-T6) of luminous flux (F1-F6), said correction means being configured to absorb light so that the optical guide(s) (T1-T6) receiving said correction means transmit a reduced quantity of luminous flux (F1-F6), leading to identical luminosity fluxes at the output of the optical guides (T1-T6).

4. Optical unit, particularly for a motor vehicle, comprising a lighting and / or signaling device comprising at least two sources (1-6) of luminous flux (F1-F6) and at least two optical guides (T1-T6) of luminous flux (F1-F6) having different longitudinal extensions from one another, and located so that each of said sources (1-6) emits its luminous flux (F1-F6) into one of said optical guides (T1-T6), said optical guides (T1-T6) being made of a material capable of absorbing part of the luminous flux (F1-F6) it transmits, said device being configured to correct an intensity of the luminous fluxes (F1-F6) at the output of said optical guides (T1-T6), the use of the correction of the intensity of the emitted fluxes, to homogenize the luminous fluxes transmitted by the different optical guides (T1-T6) of said fluxes within said optical unit (10), allowing to homogenize the rendered appearance, characterized in that the optical unit is configured such that each of the optical guides (T1-T6) of luminous flux (F1-F6), positioned facing one of said sources (1-6), is defocused from said source (1-6), along a longitudinal axis of said optical guide (T1-T6), and / or along an axis perpendicular to said longitudinal axis, so that the sources are progressively defocused along a longitudinal axis of said optical guide, or along an axis perpendicular to said longitudinal axis, leading to identical luminosity fluxes at the output of the optical guides.

5. Optical unit according to one of the preceding claims, wherein said sources (1-6) of luminous flux (F1-F6), and / or said optical guides (T1-T6) are configured to correct an intensity of the luminous fluxes (F1-F6) at the output of said optical guides (T1-T6).

6. Optical unit according to claim 1, wherein said correction means is an electronic component, in particular an electric dipole (R1-R6).

7. Optical unit according to one of the preceding claims, wherein the sources (1-6) of luminous flux (F1-F6) comprise one or more light-emitting diodes (1'-6').

8. Optical unit according to claim 3, wherein said correction means is in the form of an addition of material, capable of absorbing part of the luminous flux (F1-F6) passing through it, said material being injected into at least a part (Z1-Z6) of at least one of said optical guides (T1-T6).

9. Optical unit according to the preceding claim, wherein said material (M1-M6) is injected at the ends facing the light sources (1-6).

10. Optical unit according to one of claims 8 or 9, wherein said material (M1-M6) injected into at least a part (Z1-Z6) of at least one of the optical guides (T1-T6) is identical, or different for each of said optical guides (T1-T6) into which the material(s) is / are injected.

11. Optical unit according to any one of claims 8 to 10, wherein said material (M1-M6) is injected into at least a part (Z1-Z6) of at least one of the optical guides (T1-T6) which is identical, or different for each of said optical guides (T1-T6) into which the material(s) is / are injected.

12. Optical unit according to one of the preceding claims, characterized in that the optical guides are made of plastic material or glass.

13. Optical unit according to one of the preceding claims, characterized in that said device comprises a means for controlling the amount of current supplied to said sources (1-6), said control means being capable of reducing the amount of current supplied to some of the luminous flux sources and / or increasing the amount of current supplied to another part of said sources, so that two adjacent sources do not emit the same luminous flux.

14. Optical unit according to - claims 1 and 3, optionally together with one of claims 5 to 13, or claims 1 and 4, optionally together with one of claims 5 to 7, or 12 to 13, or claims 2 and 3, optionally together with one of claims 5, or 7 to 13, when they do not depend on claim 1, or claims 2 and 4, optionally together with one of claims 5, or 7, or 12 to 13, when they do not depend on claim 1, or claims 1 and 3 and 4, optionally together with one of claims 5 to 13, or - claims 2 and 3 and 4, optionally together with one of claims 5, or 7 to 13, when they do not depend on claim 1.