Luminous signaling device for a motor vehicle comprising a flexible and transparent light guide

Abstract

Motor vehicle signaling light device comprising a transparent and flexible light guide The present invention relates to a motor vehicle signaling light device (200) comprising: a transparent and flexible light guide (205) comprising: a light guide sheet (201) configured to emit light towards the outside of said sheet; at least one group of light injection elements (202a, 202b, 202c) being configured to illuminate a region of said light guide sheet (201); a light source (203a, 203b, 203c) coupled to said at least one group of light injection elements (202a, 202b, 202c). According to the invention, the light source (203a, 203b, 203c) has a property corresponding to a motor vehicle signaling function associated with said light source (203a, 203b, 203c). Figure to be published with the abstract: Figure 2a

Description

Title of the invention: Luminous signaling device for a motor vehicle comprising a flexible and transparent light guide 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 by 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. la]. The directions x, y and z are defined in relation to the reference frame illustrated in [Fig. la], and in [Fig. lb].

[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 has a thickness along the x axis of between 200 and 1000 micrometers and 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 light rays in the flexible film 111 is made by the total internal reflection due 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 side 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. Thus, the light injection elements 102.1 remain attached to the light guide sheet 110 on one of their ends. Shearing 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 the light to the transparent guide sheet and is based on the cutting of the raw sheet for forming 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 a flexible and transparent surface light guide and which performs at least one signaling function. This device provides good brightness while being inexpensive, lightweight, robust and simple to produce.

[0025] To this end, the invention relates to a luminous signaling device for a motor vehicle comprising: • a transparent and flexible 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; • a light source coupled to said at least one group of light injection elements;

[0026] According to the invention, the light source has a property corresponding to a motor vehicle signaling function associated with said light source.

[0027] The light guide is surface-mounted and flexible. Thus, it can adapt to any type of flat or curved surface. A surface-mounted light guide is understood to mean an optical guide element one of whose dimensions is much smaller than the other two dimensions in space, for example one or more orders of magnitude smaller. The light guide thus obtained makes it possible to couple the light source to the guide sheet so as to perform a motor vehicle signaling function. In addition, the lighting device comprising such a light guide is flexible, robust, lightweight, low-cost and capable of illuminating a large surface without requiring numerous light sources.

[0028] For example, the guide sheet may comprise return elements for reflecting light rays towards the outside thereof. The return elements may be microstructures, prisms, or even particles in suspension integrated into the guide sheet.

[0029] A property of the light source is understood to mean a physical property of the light emitted by the source. The property of the light source may be, for example, the wavelength or color of the emitted light, the intensity of the emitted light, or a variation over time of the emitted intensity.

[0030] Advantageously, the signaling function is chosen from a group comprising: the position light, the daytime running light, the brake light, the direction indicator and the driving mode indicator; this allows, for example, the use of the device according to the invention in a motor vehicle.

[0031] In this document, the motor vehicle signaling function means a light activation integrated into the motor vehicle allowing other road users to be informed 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.

[0032] 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.

[0033] 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.

[0034] Advantageously, the light guide comprises at least two groups of light injection elements. Furthermore, the light device comprises at least two light sources, each light source being coupled to a group of light injection elements and associated with a different signaling function.

[0035] Thus, the proposed lighting device makes it possible to use a different light source for each signaling function, so as to efficiently perform several signaling functions with the same device.

[0036] According to one embodiment, the two groups of light injection elements are associated with the same region of the light guide sheet. Thus, the multiplicity of signaling functions is achieved through the use of light sources having different properties. This arrangement of the groups of light injection elements make it possible, for example, to reduce the size of the device according to the invention by using the same region of the guide sheet to perform two signaling functions.

[0037] By way of example, the light guide comprises a first group of injection elements and a second group of injection elements which are arranged on either side of the light guide sheet, the first group of light injection elements being coupled to a first light source, the second group of light injection elements being coupled to a second light source, the first light source being associated with a first signaling function and the second light source being associated with a second signaling function. In an exemplary embodiment, the first light source is associated with the position light type signaling function and the second light source is associated with the direction indicator or driving mode indicator type signaling function.

[0038] Alternatively, the two groups of light injection elements may be configured to illuminate two different regions of the light guide sheet when the latter comprises at least two regions.

[0039] Advantageously, the groups of light injection elements extend on the same side of the light guide sheet. This makes it possible, for example, to bring together all the light sources in a single location and thus simplify the routing for controlling and powering these sources.

[0040] In an exemplary embodiment, the two light sources are mounted on a common support. This makes it possible to reduce the number of components in the lighting device.

[0041] Alternatively, the light device comprises at least two light source supports, each light source being mounted on an individual support. This allows the use of reduced size supports for the light sources.

[0042] Advantageously, the groups of light injection elements are arranged on two opposite sides of the light guide sheet. This configuration can meet space constraints in the vehicle in which the light device is mounted.

[0043] Advantageously, the or each region of the light guide sheet comprises a light emission zone forming a light pattern.

[0044] Advantageously, each light injection element comprises a main portion extending from the transparent film and an end portion, the main portion and the end portion being separated by a fold at a folding element of the coupling element and the end portions belonging to the same group of light injection elements are superimposed so as to form a stack.

[0045] Advantageously, the supports for the light sources comprise a printed circuit.

[0046] Another object of the invention relates to a motor vehicle comprising a lighting device according to the invention. BRIEF DESCRIPTION OF THE FIGURES

[0047] 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.2a] illustrates a first embodiment of the light device according to the invention; • [Fig.2b] illustrates a second embodiment of the light device according to the invention; • [Fig.2c] illustrates a third embodiment of the light device according to the invention; • [Fig.3a] illustrates a fourth embodiment of the light device according to the invention; • [Fig.3b] shows a fifth embodiment of the light device according to the invention; • [Fig.3c] shows a sixth embodiment of the light device according to the invention. DETAILED DESCRIPTION

[0048] The figures are presented for information purposes only and in no way limit the invention.

[0049] Figures [Fig.1a], [Fig.1b], [Fig.1c] and [Fig.1d] have been described in relation to the state of the art.

[0050] [Fig.2a] shows a first embodiment of the light device 200 according to the invention.

[0051] The light device 200 according to the embodiment of [Fig.2a] comprises: • a 205 light guide with: • a light guide sheet 201 adapted to guide the light inside it and having a light emitting face; • three groups of light injection elements 202a, 202b and 202c, each group comprising eight light injection elements cut from the same raw sheet as the guide sheet 201; • three folding elements (not visible in the figure) each forming a stack 200a, 200b and 200c of light injection elements from the corresponding group of light injection elements; • three light sources 203a, 203b and 203c, each light source being coupled to a stack corresponding to a group of light injection elements 202a, 202b and 202c.

[0052] In the example of [Fig.2a] each group of light injection elements 202a, 202b and 202c is associated with a region of the light guide sheet 201. Here, each region comprises a light emission zone of the flexible film. Each zone comprises a different light pattern.

[0053] The lighting device 200 according to the first embodiment further comprises an individual support for each light source 203a, 203b and 203c. Advantageously, this makes it possible to reduce the size of the electronic circuits used to power the light sources.

[0054] As is known in the prior art, each light injection element of a group 202a, 202b, 202c comprises a main portion extending from the flexible film (not referenced in [Fig.2a]). Each group of light injection elements comprises the corresponding end portions (not referenced in [Fig.2a]).

[0055] The main parts of the light injection elements belonging to the group 202a are in contact with the same support element during folding and folded to form the corresponding end parts. The end of the stack from the group 202a is coupled to the light source 203a.

[0056] Similarly, the main parts of the light injection elements belonging to group 202b are in contact with the same support element upon folding and folded to form the corresponding end parts. The main parts of the light injection elements corresponding to group 202c are in contact with the same support element upon folding and folded to form the corresponding end parts.

[0057] In total, the light device 200 illustrated in [Fig.2a] comprises three stacks of light injection elements. In the non-limiting example illustrated in [Fig.2a], each stack 200a, 200b and 200c comprises an end facing a light source 203a, 203b or 203c.

[0058] In the example of [Fig.2a], each light source 203a, 203b or 203c is positioned on an individual support. Each individual support comprises a dis- heat sip.

[0059] According to one embodiment, the light sources 203a, 203b or 203c are semiconductor light sources. In a non-limiting embodiment, the semiconductor light sources are part of a light-emitting diode or a laser diode. By light-emitting diode, we mean any type of light-emitting diode, whether in non-limiting examples LEDs (“Light Emitting Diode” in English), OLEDs (“Organic LED” in English), AMOLEDs (“Active-Matrix-Organic LED” in English), or FOLEDs (“Flexible OLED” in English).

[0060] According to one embodiment, the first light source 203a is associated with a signaling function of the positioning light or daytime running light type. In this case, the source 203a emits a white light.

[0061] According to one embodiment, the second light source 203b is associated with a direction indicator type signaling function. In this case, the source 203b emits an orange-colored light. The light source 203b may have a light intensity that varies over time so as to provide a flashing light indication.

[0062] According to one embodiment, the third light source 203c is associated with an autonomous driving type signaling function. In this case, the source 203c emits a cyan-colored light.

[0063] The light guide sheet 201 may comprise a film made of polycarbonate, PC, polymethyl methacrylate, PMMA, thermoplastic polyurethane, TUP, or polyethylene terephthalate, PET. The light guide sheet 201 may have a thickness, i.e. a dimension along the X axis, of between 200 and 1000 micrometers. More specifically, the thickness of the flexible film may be between 50 and 1000 micrometers, for example between 200 and 500 micrometers.

[0064] The aforementioned materials, combined with a low thickness as described above, make it possible to obtain a flexible and transparent film. Other materials may be provided for the composition of the flexible film. However, it is preferable according to the invention to provide deformable and transparent materials.

[0065] [Fig.2b] illustrates the second embodiment of the light device 200' according to the invention. According to this embodiment, the light sources 203a, 203b and 203c are positioned on the same support 204. The device 200' further comprises a heat dissipation element 207

[0066] [Fig.2c] illustrates the third embodiment of the light device 200'' according to the invention. In this embodiment, the light guide sheet 201 comprising the flexible and transparent film is cut along the parallel lines 207 and 208. This makes it possible to arrange the three light emission zones according to planes different and shifted in space.

[0067] In the embodiments illustrated in [Fig.2a], [Fig.2b] and [Fig.2c] all the groups of light injection elements extend on the same side of the flexible film. This makes it possible to position all the light sources close to each other or on the same support.

[0068] [Fig.3a] illustrates the fourth embodiment of the light device 300 according to the invention. According to this embodiment, the device 300 comprises: • a light guide 305 with: • a light guide sheet 301; • a first group of light injection elements 302a extending from a first side 314 of the transparent film; • a second group of light injection elements 302b extending from a second side 315 of the transparent film; and • a first light source 303a coupled to the first group of light injection elements 302a; and • a second light source 303b coupled to the second group of light injection elements 302b.

[0069] Advantageously, the device 300 according to the fourth embodiment has a single region coupled to two groups of light injection elements. Due to the fact that the two light sources 303a and 303b have different properties, it is possible to implement two signaling functions in the same emission zone. It follows that the device 300 according to the fourth embodiment has a particularly reduced footprint.

[0070] According to the embodiment illustrated in [Fig.3a], the first light source 303a is associated with the position light signaling function. The second light source 303b is associated with the direction indicator type signaling function.

[0071] [Fig.3b] illustrates the fifth embodiment of the device 300' according to the invention. The fifth embodiment is identical to the embodiment illustrated in [Fig.3a] except for the signaling function of the second light source 303b which is in this case an autonomous driving signal.

[0072] [Fig.3c] illustrates the fifth embodiment of the device 300” according to the invention. The fifth embodiment is identical to the embodiment illustrated in [Fig.3b] except for the light pattern formed by the light guide which is in this case a symbol indicating autonomous driving.

Claims

Claims

1. Motor vehicle lighting device (200; 200'; 200”; 300; 300'; 300”) comprising: • a transparent and flexible light guide (205; 305) comprising: • a light guide sheet (201; 301) 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 two groups of light injection elements (202a, 202b, 202c); said at least two groups of light injection elements (202a, 202b, 202c) are configured to illuminate two different regions of said light guide sheet (201); • at least two light sources (203a, 203b, 203c), each light source (203a, 203b, 203c) being coupled to a group of light injection elements (202a, 202b, 202c); said light device (200; 200'; 200”; 300; 300'; 300”) being characterized in that: - the light device is configured to perform at least one motor vehicle signaling function; - each of said at least two light sources (203a, 203b, 203c; 303a, 303b) has a property corresponding to a different motor vehicle signaling function; - said at least two groups of light injection elements (202a, 202b, 202c) are arranged on the same side of said light guide sheet (201): and - said at least two light sources (202a, 202b, 202c) are mounted on a common support (204) of the lighting device.

2. Luminous device (200; 200'; 200”; 300; 300'; 300”) according to the preceding claim, characterized in that the property of the light source (203a, 203b, 203c; 303a, 303b) associated with said signaling function is the color and / or the intensity of the light emitted by the source.

3. Lighting device (200; 200'; 200”; 300; 300'; 300”) according to one of the preceding claims, characterized in that the signaling function is chosen from a group comprising: the position light, the daytime running light, the brake light, the direction indicator and the driving mode indicator.

4. Motor vehicle comprising a light device (200; 200'; 200”; 300; 300'; 300”) according to one of the preceding claims.

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