Signaling lighting device of motor vehicle comprising flexible and transparent light guide

Abstract

The invention relates to a signalling lighting device for a motor vehicle (200), the signalling lighting device comprising: a transparent and flexible light guide (205) comprising: a light guide sheet (201) configured to emit light towards the outside of the sheet; at least one group (202a, 202b, 202c) of light injection elements, the at least one group of light injection elements being configured to illuminate an area of the light guide sheet (201); and a light source (203a, 203b, 203c) coupled to the light injection elements of the at least one group (202a, 202b, 202c). According to the invention, the light source (203a, 203b, 203c) has characteristics corresponding to a motor vehicle signaling function associated with the light source (203a, 203b, 203c).

Description

Technical Field

[0001] The technical field of the present invention is the field of signaling lighting devices for motor vehicles.

[0002] More specifically, a subject matter of the invention relates to a lighting device with multiple signaling functions, comprising a flexible and transparent light guide. Background Art

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

[0004] [ Figure 1a ]and[ Figure 1b An example of a light guide 105 is shown in FIG. The light guide 105 comprises a flexible guide sheet 110 capable of receiving light through a light injection edge 114 and returning the light in a direction x substantially perpendicular to the surface of the flexible guide sheet, the flexible guide sheet thus being in [ Figure 1a ] extends in the plane yz. Directions x, y, and z are relative to [ Figure 1a ]and[ Figure 1b ] is defined by the reference frame shown.

[0005] A guide sheet is a guiding optical element having one of its spatial dimensions much smaller than the other two dimensions. In this case, the guide sheet is a flexible guide sheet whose thickness along the axis x is at least two orders of magnitude smaller than its dimension in the plane yz in which the flexible guide sheet 110 extends. For example, the guide sheet has a thickness along the axis x of between 200 and 1000 microns and extends over several centimeters in the directions y and z.

[0006] The flexible guide sheet 110 may comprise a flexible membrane 111 at its core, the flexible membrane comprising a light injection edge 114. The flexible membrane further comprises a collection of microstructures 113 capable of returning light guided in the flexible membrane 111 to the exterior of the flexible guide sheet 110, in particular in one or more directions substantially along the axis x. In one exemplary embodiment, the light is directed according to [ Figure 1a ] The orientation shown is re-emitted in the +x direction. For example, the light is emitted to the outside of the front of the vehicle.

[0007] The flexible guide sheet 110 may further comprise one or two optional protection layers 112 . 1 and 112 . 2 enabling mechanical protection of the flexible membrane 111 .

[0008] Due to the difference between the refractive index of the flexible film 111 and the refractive index of the glue or adhesive layer applied to at least one side of the flexible film, light travels through the flexible film 111 by total internal reflection.

[0009] The flexible guide sheet 110 or specifically the flexible membrane 111 may include a mixing zone 111.2 and several areas 111.1, each area including a luminous emission zone, which is provided with light extraction elements 113, which are capable of returning the light guided in the flexible membrane 111 to the outside of the flexible guide sheet 110, especially in one or more directions substantially along the axis x.

[0010] Mixing zone 111.2 is positioned upstream of the light-emitting zone in the direction of light travel within light-guiding sheet 110. Light injected into light-guiding sheet 110 via edge 114 is mixed in light-mixing zone 111.2 to achieve better light uniformity. The light then travels into different zones, or more specifically, into light-emitting zones 111.1, through which it is re-emitted from light-guiding sheet 110 in direction x. Thus, while a zone receives light from its associated group of light-injection elements, the light-emitting zone returns light to the outside, displaying a light pattern.

[0011] By way of example, the light extraction element 113 may be a microstructure 113 etched into the flexible film 111. In the remainder of the description, the microstructure 113 is referred to as an example of a light extraction element 113.

[0012] In one exemplary embodiment, the light is Figure 1a ] The orientation shown is re-emitted in the +x direction. For example, the light is emitted to the outside of the front of the vehicle.

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

[0014] The group 102 comprises a number of light injection elements 102.1. For example, it comprises between three and ten light injection elements 102.1. Figure 1b In the example of , the light guide 105 comprises a group 102 of ten light injection elements 102.1. The group 102 injects light into the guiding sheet 110, in particular into the area 111.1.

[0015] It should be noted that during the production process for producing the light guide 105, the light injection element 102.1 and the light guide sheet 110 are made from a large unfinished sheet that will be trimmed at one end in order to be aligned along [ Figure 1a ]or Figure 1bThe illustrated axis y separates the different light injection elements 102.1 and thus forms the different light injection elements 102.1 and the light directing sheet 110. Thus, the light injection elements 102.1 remain attached at one of their ends to the light directing sheet 110. Trimming the unfinished sheet means cutting through all the layers comprised in the unfinished sheet in order to form parallel strips constituting the light injection elements 102.1.

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

[0017] Specifically, as [ Figure 1c ], each light injection element 102.1 is composed of the following: a main portion 102.12 cut from and extending from the light directing sheet, and • An end portion 102.13, which extends along the axis z.

[0018] The end portion 102.13 is connected to the light guiding sheet 110 by means of the main portion 102.12. The main portion 102.12 and the end portion 102.13 are connected to the light guiding sheet 110 by means of the main portion 102.12. Figure 1d ] is divided by a fold 102.14 at a fold element not shown in FIG. The end portion 102.13 extends behind the fold 102.14. The fold 102.14 is a right-angled fold. Figure 1c ] shows the end portions 102.13, the main portion 102.12, and the folds 102.14 separating the end portions and the main portion of the light injection elements 102.1 in the group 102. The total length Lg' of the light injection element 102.1 is the sum of the lengths of the main portion 102.12 and the end portion 102.13.

[0019] like[ Figure 1d ], the light injection elements 102.1 in the group 102 are folded so that their end portions 102.13 form a stack 123 having a thickness E adapted to fit the emission surface of the light source 20. The thickness E is the sum of the thicknesses e of each light injection element 102.1, the end portions 102.13 of each light injection element forming the stack 123. The stack 123 has an entrance surface 123.1 formed by the ends of the end portions 102.13 of each light injection element 102.1 in the group 102.

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

[0021] Given that the light injection element is integral with the light guiding sheet, the light ray R will travel by total internal reflection in the light injection element 102.1 in group 102 so as to bring the light to the light guiding sheet 101, which is adjacent to and attached to the light injection element 120.1 and thereby illuminates an area of ​​the light guiding sheet 110.

[0022] Figure 1a 、 Figure 1b 、 Figure 1c and Figure 1d The illustrated solution enables efficient coupling of light to the transparent guide sheet and is based on cutting the unfinished sheet to form stacks of light injection elements that can be coupled to at least one light source mounted on the printed circuit 103 .

[0023] However, the use of this technical solution remains neglected in the field of automotive lighting and / or signaling. Summary of the Invention

[0024] This invention proposes an adaptation of the aforementioned technical solution to automotive signaling functions. Specifically, it proposes a lighting device comprising a flexible and transparent sheet-like light guide that performs at least one signaling function. This device provides good brightness while being inexpensive, lightweight, robust, and easy to manufacture.

[0025] To this end, the present invention relates to a lighting 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 emit light to the exterior of the sheet; a plurality of light injection elements grouped together to form at least one group of light injection elements configured to illuminate an area of ​​the light directing sheet; • A light source coupled to the at least one group of light injection elements.

[0026] According to the invention, the lighting device is a signalling device which performs at least one motor vehicle signalling function.The light source has characteristics corresponding to the motor vehicle signalling function associated with said light source.

[0027] The light guide is sheet-shaped and flexible. Therefore, it can be adapted to any type of flat or curved surface. A sheet-shaped light guide is a guiding optical element in which one of the spatial dimensions is significantly smaller than the other two dimensions, for example, by one or more orders of magnitude. The resulting light guide enables coupling a light source to the guide sheet to perform motor vehicle signaling functions. Furthermore, a lighting device including such a light guide is flexible, secure, lightweight, low-cost, and capable of illuminating large surface areas without requiring numerous light sources.

[0028] For example, the guide sheet may include a return element for reflecting light to the outside thereof. The return element may be a microstructure, a prism, or suspended particles integrated in the guide sheet.

[0029] The characteristics of a light source refer to the physical properties of the light emitted by the light source. The characteristics of a light source may be, for example, the wavelength or color of the emitted light, the intensity of the emitted light, or the temporal variation of the emitted intensity.

[0030] Advantageously, the signalling function is selected from the group comprising: position lights, daytime running lights, brake lights, direction indicators and driving mode indicators; this enables the use of the device according to the invention, for example, in a motor vehicle.

[0031] In this document, a motor vehicle signalling function means a light-emitting device integrated into a motor vehicle that is used to inform other road users of the vehicle's status, driving mode, the driver's intention to change direction or brake, or to allow other users to see the vehicle more clearly.

[0032] Furthermore, a motor vehicle regulatory signalling function is a photometric function that meets the applicable legislation of the country or geographical area in which it is to be used. Regulatory signalling functions are, for example: Daytime running lights (DRL), United Nations Economic Commission for Europe (UNECE) Regulation 087, Clearance lights, UNECE Regulation 007, Brake lights, UNECE Regulation 007 or Turn signal indicators, UNECE Regulation No. 006.

[0033] These regulations may contain requirements regarding the colorimetry, intensity, spatial distribution according to so-called photometric diagrams, or the visibility range of the emitted light.

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

[0035] The proposed lighting device thus enables the use of a different light source for each signalling function in order to efficiently perform several signalling functions with the same device.

[0036] Alternatively, the two groups of light injection elements may be configured to illuminate two different areas of the light guiding sheet when the light guiding sheet comprises at least two areas.

[0037] Advantageously, the groups of light injection elements extend on the same side of the light guiding sheet. This makes it possible, for example, to group all the light sources in a single location, thus simplifying the wiring for controlling and powering these light sources.

[0038] In an exemplary embodiment, in each group of light injection elements, the light injection elements are folded so as to form a stack having a thickness suitable for adapting to the emission surface of the light source, the stack having an incident surface configured to receive light emitted by the corresponding light source. In addition, the size of the light injection elements is determined so that when the light injection elements in each of the groups are folded, the incident surfaces of the light injection elements of these groups are located at the same level. In this way, the light sources positioned facing these incident surfaces can be positioned at approximately the same level, which means that the installation of the entire system can be simplified.

[0039] In an exemplary embodiment, the two light sources are mounted on a common support. This makes it possible to further simplify the installation of the system and reduce the number of components in the lighting device.

[0040] As a variant, the lighting device comprises at least two light source supports, each light source being mounted on a separate support. This enables the use of supports of reduced size for the light sources.

[0041] According to one embodiment, two groups of light injection elements are associated with the same area of ​​the light guide sheet. Thus, multiple signaling functions are performed using light sources with different characteristics. This arrangement of these groups of light injection elements makes it possible to reduce the size of the device according to the invention, for example by using the same area of ​​the guide sheet to perform two signaling functions.

[0042] For example, the light guide includes a first group of injection elements and a second group of injection elements positioned 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 one exemplary embodiment, the first light source is associated with a position light type signaling function, and the second light source is associated with a turn indicator or driving mode indicator type signaling function.

[0043] Advantageously, the groups of light injection elements are positioned on opposite sides of the light guiding sheet.Such a configuration can meet space constraints in a vehicle in which the lighting device is installed.

[0044] Advantageously, the or each region of the light directing sheet comprises a light emitting area forming a light emitting pattern.

[0045] Advantageously, each light injection element comprises a main portion and an end portion extending from the transparent film, the main portion and the end portion being separated by a fold at the fold element of the coupling element, and the end portions of light injection elements belonging to the same group are superimposed to form a stack.

[0046] Advantageously, the support for the light source comprises a printed circuit.

[0047] A further subject matter of the invention relates to a motor vehicle comprising a lighting device according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] These figures are presented by way of indication and in no way limit the invention: ·[ Figure 1a ] shows a cross-sectional view of a light guide sheet for a light emitting device according to the prior art; ·[ Figure 1b ] presents a lighting device including a light guiding sheet according to the prior art; ·[ Figure 1c ] shows the Figure 1b ] a folding of a group of light injection elements associated with a region of a light guiding sheet of the device; ·[ Figure 1d ] shows one end of a stack of light injection elements intended to be coupled to a light source; ·[ Figure 2a ] shows a first embodiment of a light emitting device according to the present invention; ·[ Figure 2b ] shows a second embodiment of the light emitting device according to the present invention; ·[ Figure 2c ] shows a third embodiment of a light emitting device according to the present invention; ·[ Figure 3a ] shows a fourth embodiment of a light emitting device according to the present invention; ·[ Figure 3b ] shows a fifth embodiment of a light emitting device according to the present invention; ·[ Figure 3c ] shows a sixth embodiment of a light emitting device according to the present invention. DETAILED DESCRIPTION

[0049] These figures are presented by way of indication and in no way limit the invention.

[0050] The accompanying drawings have been described with respect to the prior art [ Figure 1a ]、[ Figure 1b ]、[ Figure 1c ]and[ Figure 1d ].

[0051] [ Figure 2a ] shows a first embodiment of a light emitting device 200 according to the present invention.

[0052] according to[ Figure 2a The light emitting device 200 of the embodiment of the present invention includes: A light guide 205 having: a light guiding sheet 201 adapted to guide light within its interior and having a surface for emitting light; three groups 202a, 202b and 202c of light injection elements, each group comprising eight light injection elements cut from the same unfinished sheet as guide sheet 201; three folded elements (not visible in the figures), each folded element forming a stack 200a, 200b and 200c of light injection elements from a corresponding group of light injection elements; • Three light sources 203a, 203b and 203c, each coupled to a stack of light injection elements corresponding to a group 202a, 202b and 202c.

[0053] exist[ Figure 2a ], each group 202a, 202b and 202c of light injection elements is associated with a region of the light guiding sheet 201. Here, each region comprises a light emitting zone of the flexible film. Each zone comprises a different light emitting pattern.

[0054] The lighting device 200 according to the first embodiment further comprises a separate support for each light source 203a, 203b and 203c Advantageously, this enables a reduction in the volume of the electronic circuits for powering the light sources.

[0055] As is known in the art, each light injection element in the groups 202a, 202b, 202c comprises a light emitting diode (LED) formed from a flexible film ([ Figure 2a ] is not cited in the main portion extending from the end portion. Each group of light injection elements includes a corresponding end portion ([ Figure 2a ]).

[0056] The main parts of the light injection elements belonging to group 202a are in contact with the same folding support element and are folded to form corresponding end parts.The ends of the stacks from group 202a are coupled to light sources 203a.

[0057] Similarly, the main portions of the light injection elements belonging to group 202b are in contact with the same folding support element and are folded to form corresponding end portions. The main portions of the light injection elements corresponding to group 202c are in contact with the same folding support element and are folded to form corresponding end portions.

[0058] In general, Figure 2a ] The light emitting device 200 shown comprises three stacks of light injection elements. Figure 2a ] In the non-limiting example shown, one end of each stack 200a, 200b and 200c faces the light source 203a, 203b or 203c.

[0059] exist[ Figure 2a ], each light source 203a, 203b or 203c is positioned on a separate support. Each separate support comprises a heat sink.

[0060] According to one embodiment, light source 203a, 203b, or 203c is a semiconductor light source. In a non-limiting embodiment, the semiconductor light source forms part of a light-emitting diode or a laser diode. "Light-emitting diode" refers to any type of light-emitting diode, including, by way of non-limiting example, an LED (light emitting diode), an OLED (organic LED), an AMOLED (active matrix organic LED), or a FOLED (flexible OLED).

[0061] According to one embodiment, the first light source 203a is associated with a signaling function of the position light or daytime running light type. In this case, the light source 203a emits white light.

[0062] According to one embodiment, the second light source 203b is associated with a signaling function of the turn signal type. In this case, the light source 203b emits orange light. The light source 203b can have a luminous intensity that varies over time in order to produce a flashing luminous indication.

[0063] According to one embodiment, the third light source 203c is associated with a signaling function of the autonomous driving type. In this case, the light source 203c emits cyan light.

[0064] Light guiding sheet 201 may include a film made of polycarbonate (PC), polymethyl methacrylate (PMMA), thermoplastic polyurethane (TPU), or polyethylene terephthalate (PET). The thickness of light guiding sheet 201 (i.e., the dimension along the X-axis) may be between 200 and 1000 microns. More specifically, the thickness of the flexible film may be between 50 and 1000 microns, for example, between 200 and 500 microns.

[0065] The above materials, associated with the small thickness as described above, enable a flexible and transparent film to be obtained. Other materials can be considered for the composition of the flexible film. However, according to the invention it is preferred to provide a deformable and transparent material.

[0066] [ Figure 2b ] shows a second embodiment of a lighting 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 sink element 207.

[0067] [ Figure 2c ] shows a third embodiment of a light emitting device 200" according to the invention. In this embodiment, the light guide sheet 201 comprising a flexible and transparent film is cut along parallel lines 207 and 208. This enables the positioning of three light emitting zones along different planes that are spatially offset.

[0068] exist[ Figure 2a ]、[ Figure 2b ]and[ Figure 2c In the embodiment shown, all groups of light injection elements extend on the same side of the flexible membrane. This makes it possible to position all light sources close to each other or on the same support.

[0069] [ Figure 3a ] shows a fourth embodiment of a light emitting device 300 according to the present invention. According to this embodiment, the device 300 comprises: A light guide 305 having: Light guiding sheet 301; A first group 302a of light injection elements extending from a first side 314 of the transparent film; • a second group 302b of light injection elements extending from the second side 315 of the transparent film; and a first light source 303a coupled to the first group 302a of light injection elements; and • A second light source 303b coupled to the second group of light injection elements 302b.

[0070] Advantageously, the device 300 according to the fourth embodiment has a single area coupled to two groups of light injection elements. Due to the fact that the two light sources 303a and 303b have different characteristics, two signaling functions can be implemented in the same emission area. As a result, the device 300 according to the fourth embodiment has a particularly reduced volume.

[0071] according to[ Figure 3a In the embodiment shown, the first light source 303a is associated with a position light signaling function, and the second light source 303b is associated with a direction indicator type signaling function.

[0072] [ Figure 3b ] shows a fifth embodiment of the device 300' according to the present invention. The fifth embodiment is similar to [ Figure 3a ] is identical to the embodiment shown, except for the signaling function of the second light source 303b, which in this case is an autonomous driving signal.

[0073] [ Figure 3c ] shows a sixth embodiment of the device 300" according to the present invention. The sixth embodiment is similar to [ Figure 3b ] is identical to the embodiment shown, except that the luminous pattern formed by the light guide is, in this case, a symbol indicating autonomous driving.

Claims

1. A light emitting device (200; 200'; 200”；300；300'； 300”), the light emitting device comprises: A transparent and flexible light guide (205; 305), comprising: a light guiding sheet (201; 301) configured to guide light by total internal reflection and emit light to the exterior of the sheet; A plurality of light injection elements, the plurality of light injection elements being grouped together to form at least one group (202a, 202b, 202c; 302a, 302b), the at least one group of light injection elements being configured to illuminate an area of ​​the light guiding sheet (201; 301); a light source (203a, 203b, 203c; 303a, 303b) coupled to the at least one group (202a, 202b, 202c; 302a, 302b) of light injection elements; The lighting device (200; 200'; 200"; 300; 300'; 300") is characterized by: - the lighting device is a signalling device that performs at least one motor vehicle signalling function; - the light sources (203a, 203b, 203c; 303a, 303b) have characteristics corresponding to the at least one motor vehicle signaling function.

2. The lighting device (200; 200'; 200"; 300; 300'; 300”), characterized in that said light source (203a, 203b, 203c; associated with said at least one signaling function; 303a, 303b) is the color and / or intensity of the light emitted by said light source.

3. The lighting device (200; 200'; 200"; 300; 300'; 300"), characterized in that The at least one signaling function is selected from the group consisting of: position lights, daytime running lights, brake lights, turn indicators, and driving mode indicators.

4. The lighting device (200; 200'; 200"; 300; 300'; 300"), characterized in that - the light guide (205) comprises at least two groups (202a, 202b, 202c) light injection element; - the device comprises at least two light sources (203a, 203b, 203c), each light source (203a, 203b, 203c) being coupled to a group (202a, 202b, 202c) of light injection elements and being associated with a different signaling function.

5. The lighting device (200; 200'; 200") according to claim 4, characterized in that The at least two groups (202a, 202b, 202c) of light injection elements are configured to illuminate two different areas of the light guiding sheet (201).

6. Lighting device (200; 200'; 200") according to the preceding claim, characterized in that The at least two groups (202a, 202b, 202c) of light injection elements are positioned on the same side of the light guiding sheet (201).

7. The lighting device (200; 200'; 200") according to the preceding claim, characterized in that: - in each group (10) of light injection elements (100), the light injection elements (100) are folded so as to form a stack (103) having a thickness (e) adapted to accommodate the emission surface (s1) of a light source (20), the stack (103) having an entrance surface (123.1) configured to receive light emitted by the corresponding light source (20); and The light injection elements (100) are dimensioned such that the entrance surfaces (123.1) of the light injection elements of the groups (202a, 202b, 202c) are located at the same level when the light injection elements of each of the groups are folded.

8. The lighting device (200; 200'; 200") according to claim 6 or 7, characterized in that The at least two light sources (202a, 202b, 202c) are mounted on a common support (204) of the light emitting device.

9. The lighting device (300; 300'; 300") according to claim 4, characterized in that The at least two groups (302a, 302b) of light injection elements are associated with the same area of ​​the light guiding sheet (301).

10. The lighting device (300; 300'; 300") according to claim 5 or 9, characterized in that The at least two groups (302a, 302b) of light injection elements are positioned on opposite sides (314, 315) of the light guiding sheet (301).

11. A motor vehicle comprising a lighting device (200; 200'; 200"; 300; 300'; 300") according to one of the preceding claims.

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