Luminous signaling device for a motor vehicle comprising at least two superimposed flexible and transparent light guides

Abstract

Motor vehicle signaling light device comprising at least two superimposed flexible and transparent light guides The invention relates to a motor vehicle signaling light device (1.1) comprising at least two flexible and transparent light guides (G1, G2, G3), each light guide comprising: a light guide sheet configured to guide light by total internal reflection and to emit light towards the outside of said sheet; a group of light injection elements configured to illuminate a region of said light guide sheet; and at least two light sources (S1, S2, S3), each light source being coupled to a flexible and transparent light guide. According to the invention, the two light guides are at least partially superimposed on each other. The light sources have a property representative of a motor vehicle signaling function.Figure to be published with the abstract: Figure 5a.

Description

Title of the invention: Luminous signaling device for a motor vehicle comprising at least two superimposed flexible and transparent light guides TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of luminous signaling devices for automobiles.

[0002] In particular, an object of the invention relates to a luminous device with multiple signaling functions comprising a flexible and transparent light guide. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] Flexible transparent films suitable for guiding light are known as described for example in application WO 2011 / 130715 A2.

[0004] An example of a light guide 105 is illustrated in [Fig.1a] and [Fig.1b]. The light guide 105 comprises a flexible guide sheet 110 capable of receiving light rays via a light injection edge 114 and of returning the light rays in a direction x substantially normal to a surface of the flexible guide sheet which thus extends in a plane yz in [Fig.1a]. The directions x, y and z are defined in relation to the reference frame illustrated in [Fig.1a] and [Fig.1b].

[0005] A guide sheet is understood to mean an optical guide element one of whose dimensions is much smaller than the other two dimensions in space. Here, a flexible guide sheet is considered whose thickness along the x axis is at least two orders of magnitude smaller than its dimensions along the yz plane in which the flexible guide sheet 110 extends. For example, the guide sheet, a thickness along the x axis of between 200 and 1000 micrometers, extends over several cm along the y and z directions.

[0006] The flexible guide sheet 110 may comprise a flexible film 111 at its core comprising the light injection edge 114. The flexible film further comprises a set of microstructures 113 capable of returning the light rays guided in the flexible film 111 outside the flexible guide sheet 110, in particular in one or more directions substantially along the x axis. In an exemplary embodiment, the light rays emerge in the +x direction according to the orientation illustrated in [Fig.1a]. For example, the light rays are emitted towards the outside of the front face of a vehicle.

[0007] The flexible guide sheet 110 may further comprise one or two optional protective layers 112.1 and 112.2, which make it possible to mechanically protect the flexible film 111.

[0008] The propagation of the light rays in the flexible film 111 is done by total internal reflection thanks to the difference between the refractive index of the flexible film 111 and that of a layer of glue or adhesive applied to at least one face of the flexible film.

[0009] The flexible guide sheet 110, or precisely the flexible film 111, may comprise a mixing zone 111.2 and several regions 111.1, each region comprising a light emission zone provided with light extraction elements 113 capable of returning the light rays guided in the flexible film 111 outside the flexible guide sheet 110, in particular in one or more directions substantially along the x axis.

[0010] The mixing zone 111.2 is arranged upstream of the light emission zone according to the direction of propagation of the light rays within the guide sheet 110. The light injected into the light guide sheet 110 via the edge 114 will be mixed in the light mixing region 111.2 in order to obtain better light homogeneity. The light then propagates in the different regions, or precisely in the light emission zones 111.1 through which the light emerges from the light guide sheet 110 in the x direction. Thus, when a region receives light from the group of light injection elements associated with it, the light emission zone reflects light towards the outside and displays a light pattern.

[0011] As an example, the light extraction elements 113 may be microstructures 113 etched in the flexible film 111. In the remainder of the description, the microstructures 113 are cited as an example of the light extraction elements 113.

[0012] In an exemplary embodiment, the light rays emerge in the +x direction according to the orientation illustrated in [Fig. 1a]. For example, the light rays are emitted outward from the front face of a vehicle.

[0013] The light guide 105 according to the state of the art further comprises at least one group 102 of light injection elements.

[0014] A group 102 comprises several light injection elements 102.1. For example, it comprises between three and ten light injection elements 102.1. In the example of [Fig.lb], the light guide 105 comprises a group 102 with ten light injection elements 102.1. The group 102 injects light into the guide sheet 110, in particular into the region 111.1.

[0015] It will be noted that during the manufacturing process of the light guide 105, the light injection elements 102.1 and the light guide sheet 110 are manufactured from a large raw sheet which is sheared on one end to separate the different light injection elements 102.1 along the y axis illustrated in [Fig.1a] or 1b and thus form the different light injection elements 102.1 and the light guide sheet 110. light guide 110. Thus, the light injection elements 102.1 remain attached to the light guide sheet 110 on one of their ends. Shearing of the raw sheet means cutting all the layers included in the raw sheet to form parallel strips constituting the light injection elements 102.1.

[0016] By means of a folding element (not shown in the figures) contained in the light guide, each light injection element is folded to form a stack of light injection elements as shown in [Fig. 1e] and [Fig. 1d].

[0017] Indeed, as illustrated in [Fig. 1e], each light injection element 102.1 is composed of: • a main portion 102.12 which is cut from the light guide sheet and extends from the light guide sheet, and • an end portion 102.13 which extends along the z axis.

[0018] The end portion 102.13 is connected to the light guide sheet 110 by means of the main portion 102.12. The main portions 102.12 and the end portion 102.13 are divided by a fold 102.14 at a folding element not shown in [Fig.1d]. The end portion 102.13 extends after the fold 102.14. The fold 102.14 is a right-angled fold. [Fig. 1c] illustrates the end portions 102.13, the main portions 102.12 of light injection elements 102.1 of a group 102 and the fold 102.14 which separates them. The total length of a light injection element 102.1 is the sum of the length of the main part 102.12 and the end part 102.13.

[0019] As illustrated in [Fig.1d], the light injection elements 102.1 of a group 102 are folded so that their end portions 102.13 form a stack 123 with thickness E adapted to an emission surface of the light source 20. The thickness E is the sum of the thicknesses e of each light injection element 102.1 whose end portions 102.13 form the stack 123. The stack 123 comprises an entry surface 123.1 formed by the ends of the end portions 102.13 of each of the light injection elements 102.1 of the group 102.

[0020] The group 102 is coupled with at least one light source 104 so as to receive the light rays R emitted by said source in each of the light injection elements.

[0021] Since the light injection elements are integral with the light guide sheet, the light rays R will propagate by total internal reflection in the light injection elements 102.1 of the group 102 so as to bring light to the light guide sheet 101 which is adjacent and attached to the light injection elements 120.1 and which will thus illuminate the region of the light guide sheet 110.

[0022] The technical solution illustrated in figures 1a, 1b, 1c and 1d makes it possible to efficiently couple effectively the light to the transparent guide sheet and relies on the cutting of the raw sheet to form stacks of light injection elements which can be coupled to at least one light source mounted on a printed circuit 103.

[0023] However, the use of this technical solution is still little known in the field of automotive lighting and / or signaling. Summary of the invention

[0024] The invention proposes an adaptation of the technical solution presented above to the automotive signaling function. Specifically, the invention proposes a light device comprising at least two flexible and transparent surface light guides and which performs at least one motor vehicle signaling function. This device provides good brightness while being inexpensive, lightweight, robust and simple to produce.

[0025] A first aspect of the invention relates to a luminous signaling device for a motor vehicle comprising: • at least two flexible and transparent light guides, each light guide comprising: • a light guiding sheet configured to guide light by total internal reflection and to emit light towards the outside of said sheet; • a plurality of light injection elements, grouped to form at least one group of light injection elements, said at least one group of light injection elements being configured to illuminate a region of said light guide sheet; and • at least two light sources, each light source being coupled to a flexible and transparent light guide.

[0026] According to the invention, the two light guides are at least partially superimposed on each other. The two light sources have a property representative of a motor vehicle signaling function.

[0027] The light device thus proposed makes it possible to perform at least one motor vehicle signaling function while remaining flexible, lightweight and robust, which facilitates the integration of the light device into the motor vehicle. In addition, the presence of two light sources each associated with a light guide offers the possibility of implementing different configurations. For example, one of the two light sources can be lit in addition to the other of the two light sources to increase the light intensity of the light device.

[0028] The light device according to the invention may optionally have one or several of the characteristics set out below.

[0029] The lighting device is configured to selectively activate the light sources. For example, the lighting device includes a control circuit that drives the light sources independently of each other.

[0030] The light sources have properties representative of different motor vehicle signaling functions. In other words, each of the light sources has a property characterizing a specific signaling function that is different from the signaling function of the other light sources. Thus, the light device becomes a multifunctional signaling device. Different signaling functions are efficiently performed by a single compact light device.

[0031] By way of example, a first light source and a second light source are configured to emit sometimes a white light, sometimes an orange light. This configuration allows the lighting device to emit either an orange light beam capable of performing the direction indicator function, or a white light beam capable of performing the daytime running light function. The lighting device is thus bi-functional.

[0032] The light guide sheet of each of the light guides comprises a light pattern. Here, the term “pattern” means any predefined spatial distribution or distribution of the light intensity emitted by the light device; a pattern may thus comprise a homogeneous distribution of the light over the entire light guide sheet. The pattern may also be a two-dimensional shape or symbol obtained by contrast between the light intensities of different positions in the XY plane of the guide sheet; the pattern may also comprise several shapes or symbols. Alternatively, a pattern covers a predefined spatial distribution of the light intensity that does not reveal a general shape, such as a distribution inducing a cloud of light points.In the context of the present invention, the light pattern is formed by a set of light extraction elements designed to redirect the light injected into the light guide sheet at least in a direction substantially normal to the sheet. For example, the light extraction elements are microstructures formed in the core of the guide sheet.

[0033] The pattern of the guide sheet of one of the light guides is different from the pattern of the guide sheet of the other light guides. Thus, by using the selective control of the light sources, the lighting device can achieve a dynamic display of the patterns. For example, the displayed pattern can vary dynamically depending on the data from the vehicle sensors.

[0034] The representative property of a motor vehicle signaling function is the color and / or intensity of the light emitted by the source and / or the variation of the emitted intensity over time.

[0035] The motor vehicle signaling function is selected from a group comprising: position light, daytime running light, brake light, direction indicator and driving mode indicator. In this document, the motor vehicle signaling function means a light activation integrated into the motor vehicle for informing other road users of the state of the vehicle, the driving mode, the driver's intention to change direction or brake, or allowing other users to see the vehicle better.

[0036] Furthermore, the regulatory signaling function of a motor vehicle is a photometric function that complies with the regulations in force in the country or geographical region where it will be used. Regulatory signaling functions are, for example: • the daytime running light (also called the “DRL” light, abbreviated from “Daytime Running Light” in English), regulation 087 UNECE (abbreviated from “United Nations Economic Commission for Europe” in English), • the position light, regulation 007 UNECE, • the brake light, regulation 007 UNECE, or • the direction indicator, regulation 006 UNECE; knowing that the regulations may contain requirements for colorimetry, intensity, spatial distribution according to a so-called photometric grid or even visibility ranges of the emitted light.

[0037] Light sources are distinct physical entities. This type of light sources is commonly used in the field of automotive lighting.

[0038] Alternatively, the light sources are arranged in a single encapsulation; this makes it possible to reduce the number of steps in the method of implementing the light sources in the light device. For example, the light sources are integrated in a two-chip light-emitting diode, comprising a first chip emitting a first color representing a first signaling function, a second chip emitting a second color representing a second signaling function. In another example, the light sources are integrated in a three-chip light-emitting diode, comprising a first chip emitting a first color representing a first signaling function, a second chip emitting a second color representing a second signaling function and a third chip emitting a third color representing a third signaling function.Colors can be chosen from white, orange or cyan.

[0039] The light device may comprise a support for the light sources.

[0040] A second aspect of the invention relates to a signaling module for a motor vehicle comprising: • a case with an opening and a case closing glass, and • at least one light device according to the invention.

[0041] The housing and the closing glass define an interior volume in which the light device is placed so that at least a portion of the light exiting the light device exits the signaling module through the closing glass.

[0042] Another aspect of the invention relates to a motor vehicle comprising the light device or the signaling module according to the invention.

[0043] The invention and its various applications will be better understood upon reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0044] The figures are presented for information purposes only and in no way limit the invention: • [Fig.1a] illustrates a sectional view of a light guide sheet used for a light device according to the state of the art; • [Fig.lb] illustrates a light device comprising a light guide sheet according to the state of the art; • [Fig. 1c] illustrates the folding of a group of light injection elements associated with a region of the light guide sheet of the device according to [Fig. 1b]; • [Fig.ld] illustrates one end of a stack of light injection elements intended to be coupled to a light source; • [Fig.2] illustrates in a schematic and non-limiting manner a front face of a motor vehicle on which is mounted a signaling module comprising a light device according to the invention; • [Fig.3] illustrates a sectional view of the signaling module according to a plane passing through line III-III illustrated in [Fig.2]; • [Fig.4] illustrates a set of three light guides in a light device according to an exemplary embodiment of the invention; • [Fig.5a] illustrates a first embodiment of the light device according to the invention; • [Fig.5b] illustrates a second embodiment of the light device according to the invention; • [Fig.5c] illustrates a third embodiment of the light device according to the invention. DETAILED DESCRIPTION

[0045] Figures [Fig.1a], [Fig.1b], [Fig.1c] and [Fig.1d] have been described in relation to the state of the art.

[0046] [Fig. 2] is a front view of a front face of a motor vehicle comprising a signaling module 2 according to an exemplary embodiment of the invention.

[0047] As seen in [Fig. 3], the signaling module 2 comprises a signaling light device 1, a housing 3 with an opening, and a closing glass 4 of the housing 3. The housing 3 and the closing glass 4 define an interior volume. The signaling light device 1 is configured to emit a light beam F, and is placed in the interior volume, so that at least a portion of the light beam F emitted by the signaling module 1 exits the signaling module 2 through the closing glass 4.

[0048] In the example presented and as illustrated in [Fig.4], the signaling light device 1, hereinafter called light device 1, comprises three flexible and transparent light guides G1, G2 and G3.

[0049] Each of the first light guide G1, the second light guide G2 and the third light guide G3 may comprise a layer of polycarbonate, PMMA, PET (polyethylene terephthalate), or TPU (thermoplastic polyurethane). These components have a transparency greater than 97%, a light extraction efficiency, when illuminated, of between 25 and 80%, and may have a luminance ranging from 100 to 1000 cd / m2 when illuminated by a light source with a luminous flux ranging from 400 lumens to 2000 lumens.

[0050] Here, the three light guides have the same configuration. Thus, to avoid redundancy, only the first light guide Gl is described and referenced in detail.

[0051] The first light guide Gl comprises: • a first light guide sheet N1; and • a first group of EL light injection elements

[0052] The first group of light injection elements El comprises a plurality of light injection elements, also called light bars. The light injection elements are folded and are superimposed on each other in order to form a stack E12. The end of the stack, also one end of the group El, is arranged facing a light source SL. The other end of the group El opens into the light guide sheet NI. Thus, the group of light injection elements El guides the light coming from the light source towards the guide sheet NI.

[0053] As for the first light guide sheet NI, this comprises a flexible film core in which the microstructures are etched. The microstructures are placed in this core according to a spatial distribution so as to form a first ML pattern. The light rays propagating in the NI guide sheet are directed towards the outside of the guide sheet against the microstructures. Thus, the pattern Ml becomes a light pattern visible to the eye when the light source SI associated with the light guide G1 is switched on.

[0054] Unless otherwise indicated, the same description will apply to the other two light guides G2 and G3. In particular, the second light guide G2 comprises a second light guide sheet N2 comprising a second pattern M2, and a second group of light injection elements E2. Similarly, the third light guide G3 comprises a third light guide sheet N3 comprising a third pattern M3, and a third group of light injection elements E3.

[0055] According to the invention and as illustrated in [Fig.4], the patterns M1, M2 and M3 of the three light guides G1, G2 and G3 are different. Each pattern can indicate a specific driving mode of the vehicle, for example the sports mode, the city driving mode, or even the autonomous driving mode. To display the patterns, the light sources S1, S2 and S3 associated with the light guides G1, G2 and G3 can be controlled independently allowing the individual lighting of these sources. This makes it possible to achieve a dynamic variation of the displayed pattern, for example a sequential lighting of the patterns one after the other. This way of displaying is particularly suitable in a welcome scenario. In another example, the displayed pattern can vary dynamically according to data from vehicle sensors.For example, a given first pattern may be displayed when an object or person is detected in the vicinity of the sensor, and a given second pattern may be displayed when no object is detected in the vicinity of the sensor.

[0056] For reasons of clarity in referencing, the three light guides G1, G2 and G3 are illustrated separately from each other in [Fig. 3]. However, according to the invention and as in the illustrated example, the three light guides G1, G2 and G3 are superimposed on each other. This involves at least partial superposition of the light guide sheet of one light guide with the light guide sheet of the other light guide (in the case of the first and second light guides G1, G3) or with the light guide sheet of the other two light guides (in the case of the second light guide G2). In the illustrated example, the three light guides G1, G2 and G3 are fully superimposed. Such an arrangement makes it possible to give the light device a compact size.

[0057] Furthermore, according to the invention and as in the illustrated example, the light sources S1, S2 and S3 have properties representative of different motor vehicle signaling functions. Specifically, each light source, associated with a light guide G1, G2 or G3, has a property representative of a specific signaling function.

[0058] For example, in a first embodiment of the light device 2.1 illustrated in [Fig.5a], the first light source S1 emits a white-colored light characterizing the daytime running light signaling function. The second light source S2 emits an orange-colored light characterizing the direction indicator signaling function. Finally, the third light source S3 emits a cyan-colored light that can characterize the autonomous driving mode.

[0059] Thus, when a light source S1, S2 or S3 is turned on, the corresponding light guide G1, G2 or G3 is illuminated by emitting a light beam performing a specific signaling function, different from the signaling function of the other two light guides. Furthermore, in the example described, the illuminated light guide also displays a light pattern M1, M2 and M3 different from the light pattern of the other light guides.

[0060] Therefore, the light device not only allows the different patterns to be selectively displayed but also allows different signaling functions to be performed. The light device as described is therefore a multifunctional signaling device.

[0061] In this embodiment, the light sources S1, S2 and S3 are separate light-emitting diodes mounted on the same support.

[0062] [Fig.5b] illustrates the light device 2.2 according to a second embodiment. Unlike the first embodiment, the first and second light sources S1 and S2 are encapsulated in the same dual-chip light-emitting diode S12.

[0063] [Fig.5c] illustrates the light device 2.3 according to a third embodiment of the invention. In this example, the three light sources S1, S2 and S3 are encapsulated in a three-chip light-emitting diode S123.

[0064] Note that the light sources S1, S2 and S3 are aligned, or at least partially aligned, with each other according to the direction of superposition of the light guides G1, G2 and G3. The direction of superposition is also the direction of emission of the light beams by these light guides towards the outside. In one example, if the lighting device is mounted on the front face of the vehicle, the direction of emission of the light beams is substantially parallel to the longitudinal axis of the vehicle and oriented towards the front. Here, in Figures 5a, 5b and 5c, the light sources S1, S2, and S3 are not illustrated as they are actually arranged in the lighting device but they follow each other from left to right in Figures 5a, 5b and 5c so that all the light sources S1, S2 and S3 are visible and can be referenced.

Claims

1.

2.

3. Claims Luminous device (1) for a motor vehicle comprising: - at least two flexible and transparent light guides (G1, G2, G3), each light guide comprising: • a light guide sheet (NI, N2, N3) configured to guide light by total internal reflection and to emit light towards the outside of said sheet; • a plurality of light injection elements (101.2), grouped to form at least one group of light injection elements (E1, E2, E3), said at least one group of light injection elements being configured to illuminate a region of said light guide sheet; - at least two light sources (S1, S2, S3), each light source being coupled to one of the flexible and transparent light guides so that the group of light injection elements of said light guide receives the light rays (R) emitted by said light source in each of the light injection elements; characterized in that: • the light device is configured to perform a function motor vehicle signaling; • said at least two light guides have the same configuration and they are completely superimposed; • said at least two light sources each have a property representative of the motor vehicle signaling function and are arranged on the same support. Luminous device (1) according to claim 1, characterized in that it is configured to selectively activate said at least two light sources (S1, S2, S3). Luminous device (1) according to claim 1 or claim 2, characterized in that said at least two light sources (S1, S2, S3) have properties representative of different motor vehicle signaling functions.

4. Luminous device (1) according to one of the preceding claims, characterized in that the light guide sheet (N1, N2, N3) of each of said at least two light guides comprises a light pattern (M1, M2, M3).

5. Luminous device (1) according to the preceding claim, the light pattern of the guide sheet of one of said at least two light guides is different from the pattern of the guide sheet of the other of said at least two light guides.

6. Luminous device (1) according to one of the preceding claims, characterized in that the property representative of a motor vehicle signaling function is the color of the light emitted by the source.

7. Lighting device (1) according to one of the preceding claims, characterized in that the motor vehicle signaling function(s) is(are) chosen from a group comprising: the position light, the daytime running light, the brake light, the direction indicator and the driving mode indicator.

8. Luminous device (1) according to one of the preceding claims, characterized in that said at least two light sources (S1, S2, S3) are distinct physical entities.

9. Luminous device (1) according to one of claims 1 to 7, characterized in that said at least two light sources (S 12; S123) are arranged in the same encapsulation.

10. Motor vehicle comprising a light device according to one of the preceding claims.

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