Flexible surface light guide for vehicles

Abstract

The present invention relates to a flexible surface light guide (1) for a vehicle (3), comprising a plurality of groups (10) of light-introducing elements (100) and a light guide sheet (11), each group (10) being associated with at least one light source (20). According to the present invention, the light guide sheet (11) comprises a plurality of sections (110), at least one light-emitting area (111) being integrated in at least one section (110), the light guide sheet (11) being adjacent to the light-introducing elements (100), and each group (10) being configured to illuminate one section (110) in the light guide sheet (11). Furthermore, the light-introducing elements (100) of one group (10) illuminating one section (110) have a different length (Lg') from the light-introducing elements (100) of another group (10) illuminating another section (110).

Description

[Technical Field]

[0001] The present invention relates to a light guide for a vehicle, which is particularly applicable to motor vehicles, but is not limited to motor vehicles. [Background technology]

[0002] An example of a light guide known to those skilled in the art is shown in Figure 1 and is designated by the reference number 5. This light guide 5 is used, for example, in decorations to illuminate them, a plurality of groups 50 of light introduction elements 500, each group 50 being associated with at least one light source 60; - A light guide sheet 51 having a plurality of areas 510 and one light emitting area 511 incorporated in one of the areas 510, the light guide sheet 51 being adjacent to the light introducing element 500, and each group 50 being configured to illuminate an area 510 within the light guide sheet 51.

[0003] Each group 50 is identically designed: the light-introducing elements 500 of a group 50 are adjacent to one another and have different lengths that increase with the distance from the light source 60. Each light-introducing element 500 of a group 50 has the same length as another light-introducing element 500 of another group 50. The light-introducing elements 500 of a group 50 are bent and overlapped at their ends to form a stack. Thus, each light-introducing element 500 has a bent portion. The at least one light source 60 associated with a group 50 is configured to emit light rays that enter through the end of the stack and can propagate through the light-introducing element 500 to the light guide sheet 51. As shown in FIG. 1 , the at least one light source 60 associated with each group 500 is arranged on one electronic support 61. Thus, there are as many electronic supports 61 as there are groups 50 of light-introducing elements 500. 1, there are three groups 50 of light-introducing elements 500 and therefore three electronic supports 61. Two electronic supports 61 are located between two groups 50. Each light source 60 has a luminous flux of about 80 lumens.

[0004] The drawback of this prior art is that the light sources 60 used are too low power for automotive applications and there is no room between the groups 50 of light introducing elements 500 to place higher power (and therefore larger) light sources with suitable electronic support and suitable (also larger) heat sinks to dissipate the heat generated by these higher power light sources. Summary of the Invention [Problem to be solved by the invention]

[0005] In this context, the invention aims to propose a light guide making it possible to overcome the above-mentioned drawbacks. [Means for solving the problem]

[0006] To this end, the present invention provides A flexible surface light guide for a vehicle, comprising a plurality of groups of light introducing elements and a light guide sheet, each group being associated with at least one light source, - the light guide sheet comprises a plurality of zones, at least one light emitting area being incorporated in at least one zone, the light guide sheet being adjacent to the light introducing element, each group being configured to illuminate one zone in the light guide sheet; and - one group of light-introducing elements illuminating one area has a different length than another group of light-introducing elements illuminating another area; The present invention proposes a light guide characterized by the above.

[0007] Thus, as will be seen in more detail below, thanks to the fact that the length of each light introducing element varies from group to group, at least one of the light sources associated with a light introducing element can be positioned far away from the light guide sheet, so as to overcome location limitations by placing the light sources in a less restricted space, thus making it possible to have an electronic support large enough to accommodate all the light sources and a heat sink large enough to cool a light source or set of light sources that are far apart.

[0008] According to non-limiting embodiments, the light guide may have one or more of the following additional features, alone or in any technically possible combination:

[0009] According to a non-limiting embodiment, in each group of light introducing elements, the light introducing elements are bent to form a stack of a thickness adapted to the light emitting surface of a light source, and the stack has a light entrance surface configured to receive light emitted by the light source.

[0010] According to a non-limiting embodiment, the dimensions of the light introducing elements are determined so that when each light introducing element in a group of light introducing elements is bent, the light entrance surfaces of the light introducing elements in these groups are at the same height.

[0011] In this way, the light sources arranged facing these incident surfaces can be positioned at approximately the same height, which means that the installation of the entire system can be simplified. In particular, if several groups of light-introducing elements are arranged on the same side of the guide sheet, the light sources can be mounted on the same printed circuit board for reasons of simplicity (since they are at the same height). Furthermore, since all light sources are on the same support, a larger support surface can be provided than with individual supports for each light source if the light sources were located at different heights. The larger support surface allows a heat sink with a large heat dissipation capacity to be associated with it. This prevents the light sources from overheating and allows them to be used for a longer period of time.

[0012] For example, the guide sheet extends in a first direction and a second direction, which directions together form the plane of the extension of the guide sheet. Regarding the light introduction elements, in the unbent state, they extend primarily in the first direction. To achieve the bent state, the light introduction elements are bent in the same manner in the second direction. The lengths of the light introduction elements (measured in the first direction) are dimensioned so that, in the bent state, the entrance faces of each group of light introduction elements are at the same height (i.e., at the same position on the axis in the second direction). Furthermore, the entrance faces are positioned at different locations on the axis in the first direction.

[0013] According to a non-limiting embodiment, the light guide can be mounted on the front of the vehicle in a mounting position in which the plane of extension of the guide sheet is perpendicular to the longitudinal axis of the vehicle. In this way, the entire surface of the guide sheet in the plane of extension is visible from the outside of the vehicle. The guide sheet has a number of sections, each incorporating a light-emitting area. These sections are offset from one another in the second direction, and the number of sections corresponds to the number of groups of guide element types.

[0014] According to a non-limiting embodiment, the light guide is transparent.

[0015] According to a non-limiting embodiment, the at least one light emitting area forms at least one pattern.

[0016] According to a non-limiting embodiment, the groups of light introducing elements are arranged on the same side of the light guide sheet to form a first set of light introducing elements.

[0017] According to a non-limiting embodiment, multiple groups of light introducing elements are arranged on a first side of the light guide sheet to form a first set of light introducing elements, and the light guide has a second set identical to the first set, which is arranged on a second side of the light guide sheet opposite the first side so as to be symmetrical to the first set with respect to the light guide sheet.

[0018] According to a non-limiting embodiment, the light source is associated with at least one light collimator, which makes it possible to reduce the loss of light from the light source and thus improve the efficiency of light propagation.

[0019] According to a non-limiting embodiment, a set of light sources associated with a group is powered by a different current than other sets of light sources associated with other groups, thereby allowing for the creation of moving images.

[0020] According to a non-limiting embodiment, the light source is a solid-state light source.

[0021] According to a non-limiting embodiment, the light sources can be operated independently of each other, allowing for the creation of moving images.

[0022] Also proposed is a light emitting device for a vehicle, characterized by comprising at least one light guide according to any one of the above features, a plurality of light sources, and at least one heat sink.

[0023] According to non-limiting embodiments, the light emitting device may have one or more of the following additional features, implemented alone or in any technically possible combination:

[0024] According to a non-limiting embodiment, the light sources are arranged on the same electronic support.

[0025] According to a non-limiting embodiment, the light sources are arranged in the same plane on the same electronic support.

[0026] According to a non-limiting embodiment, each light source is located on a different plane than the other light sources on the same electronic support.

[0027] According to a non-limiting embodiment, the light emitting device comprises at least two light guides stacked opposite each other.

[0028] According to a non-limiting embodiment of the light emitting device, - in each group of light introducing elements, each light introducing element is bent to form a stack having a thickness corresponding to the light emitting surface of the light source, the stack having an incident surface for receiving light emitted by the corresponding light source; The dimensions of each light-introducing element are determined so that when the light-introducing elements of each group are bent, the entrance faces are at the same height.

[0029] The invention and its various applications will be more clearly understood by reading the following description and examining the accompanying drawings. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a schematic diagram of a light guide according to the prior art, comprising a light guide sheet and groups of light introducing elements associated with respective light sources; [Figure 2]Schematic diagram of a vehicle light guide according to a first embodiment variant of a non-limiting embodiment of the present invention, comprising three groups of light-introducing elements associated with each light source, and a light guide sheet having multiple regions and at least one light-emitting area, with the three groups of light-introducing elements arranged on the same side of the light guide sheet. [Figure 3] A schematic diagram of a vehicle light guide according to a first embodiment variant of a non-limiting embodiment of the present invention, comprising six groups of light-introducing elements associated with each light source, and a light guide sheet having multiple regions and at least one light-emitting area, with the six groups of light-introducing elements arranged on the same side of the light guide sheet. [Figure 4] A schematic diagram of a vehicle light guide according to a second embodiment variant of a non-limiting embodiment of the present invention, comprising six groups of light-introducing elements associated with each light source, and a light guide sheet having multiple regions and at least one light-emitting area, with the six groups of light-introducing elements arranged on both sides of the light guide sheet. [Figure 5] 6 shows an enlarged view of a portion of the light guide elements of the light guide according to FIG. 2, FIG. 3, FIG. 4 or FIG. 5. [Figure 6] 6 shows a front view of a stack of light-introducing elements within the same group of light-introducing elements of the light guide according to FIG. 2, FIG. 3, FIG. 4 or FIG. 5; [Figure 7] 3 illustrates the light guide of FIG. 2 with the light introducing element unbent, according to a non-limiting embodiment. [Figure 8] 6 is an enlarged perspective view of several light introducing elements in a group of a light guide according to FIG. 2, FIG. 3, FIG. 4, or FIG. 5, in a non-limiting embodiment. [Figure 9] 3 is a schematic diagram of the light guide of FIG. 2, in which the light guide sheet has three sections with three light-emitting areas forming a pattern according to a first non-limiting pattern embodiment. [Figure 10]Schematic diagram of the light guide of FIG. 2, in which the light guide sheet has three sections with three light-emitting areas forming a pattern according to a second non-limiting pattern embodiment. [Figure 11] Schematic diagram of a vehicle lighting device according to a first embodiment variant of the first non-limiting embodiment of the lighting device, comprising the light guide of FIG. 2, light sources, an electronic support, and a heat sink, with the light sources arranged on the electronic support. [Figure 12] 12 is a schematic representation of the lighting device of FIG. 11 further comprising an optical collimator, according to a non-limiting embodiment. [Figure 13] Schematic diagram of a vehicle lighting device according to a second embodiment variant of the first non-limiting embodiment of the lighting device, comprising the light guide of FIG. 2, light sources, an electronic support, and a heat sink, with the light sources arranged on the electronic support. [Figure 14] Schematic diagram of a vehicle lighting device according to a second non-limiting embodiment of the lighting device, comprising a light guide based on Figure 2, the light guide having two groups of light-introducing elements arranged on both sides of the light guide sheet, respective light sources, two electronic supports, and two heat sinks. [Figure 15] Schematic diagram of a vehicle lighting device according to a third non-limiting embodiment of the lighting device, comprising two stacked light guides of FIG. 14, respective light sources, four electronic supports, and four heat sinks. DETAILED DESCRIPTION OF THE INVENTION

[0031] Elements that are identical in structure or function and that appear in different drawings are designated by the same reference numerals unless otherwise specified.

[0032] A light guide 1 according to the invention will be described with reference to Figures 2 to 15. The light guide 1 is a light guide for a vehicle 3. In a non-limiting embodiment, the vehicle 3 is a motor vehicle. "Motor vehicle" means any type of motorized vehicle. This embodiment is given as a non-limiting example in the remainder of the specification. In the remainder of the specification, the vehicle 3 is thus also referred to as motor vehicle 3. In non-limiting embodiment variants, the vehicle 3 is an internal combustion engine vehicle or an electric vehicle.

[0033] The light guide 1 is sheet-like and flexible. It can therefore conform to any type of flat or curved surface. A light guide sheet is understood to mean an optical guiding element (light-guiding element) in which one of its dimensions is significantly smaller (e.g., by an order of magnitude or more) than the other two spatial dimensions. In this case, the thickness e of the light guide 1 is significantly smaller than its length Lg and its width La. In a non-limiting embodiment, the light guide 1 has a thickness e (shown in FIG. 6 ) between 10 and 1000 microns. In a non-limiting embodiment variant, the thickness e is between 50 and 1000 microns. In a non-limiting example, the thickness e is 50 microns. Thus, the light guide 1 is very thin.

[0034] In a non-limiting embodiment, the light guide 1 is transparent. Thus, the light guide 1 is also referred to as a transparent film 1. The light guide is transparent, allowing light to pass through. Because the light guide 1 is transparent, a pattern (referred to as a manufacturer's pattern) can be seen through the light guide 1. The pattern is integrated into the front of the motor vehicle 3, into the headlights or rear lights (if present on the motor vehicle 3), when the light guide 1 is not lit (i.e., not emitting light). This also allows the color of the body of the motor vehicle 3 to be maintained when the light guide 1 is not lit. To illuminate the manufacturer's pattern at night, the light guide 1 is provided with a pattern 111 (described below), which may be identical to the manufacturer's pattern and allows illumination of the manufacturer's pattern.

[0035] Because the light guide 1 is sheet-like, flexible, and transparent, it is configured to be installed on the front of a motor vehicle 3 (as shown in FIG. 11 ), on a headlight (as shown in FIG. 13 ), or on a rear light (as shown in FIG. 12 ) of a motor vehicle 3. In a first non-limiting embodiment, the light guide 1 is glued. In a first non-limiting embodiment variant, the surface to which the light guide 1 is installed (such as the outer lens of the front, headlight, or rear light) has an adhesive surface for adhering the light guide 1. In a second non-limiting embodiment variant, the rear surface of the light guide 1 has an adhesive surface and is glued to the back of a decorative component. In a third non-limiting embodiment variant, both sides of the light guide 1 are adhesive. In a second non-limiting embodiment variant, the light guide 1 is not glued, but is held between the outer lens and the decorative component.

[0036] In non-limiting embodiments, the light guide 1 is made of polycarbonate (PC), polymethyl methacrylate (PMMA), thermoplastic polyurethane (TPU), or polyethylene terephthalate (PET), such materials allowing for the manufacture of a transparent and flexible light guide 1.

[0037] 2, 3, and 4, in a non-limiting embodiment, the light guide 1 extends along axis z at its width La and along axis y at its length Lg (these axes are substantially perpendicular to axis x). Note that width La and length Lg may be equal.

[0038] As shown in Figures 2, 3 and 4, the light guide 1 is a plurality of groups 10 of light introducing elements 100; a light guide sheet 11 with a plurality of zones 110; It is equipped with:

[0039] The light guide sheet 11 extends in a first direction y and a second direction z. In an unbent state, in a non-limiting embodiment, each light introducing element 100 extends primarily in the first direction y. The dimension measured in this first direction y is thus considered the length Lg' of the light introducing element 100 as shown in FIG.

[0040] During the manufacturing process of the light guide 11, each light introductory element 100 and light guide sheet 11 are produced from a large sheet that is cut at one end to separate the various light introductory elements 100 along the axis y shown in Figure 7, thereby forming the various light introductory elements 100 and light guide sheet 11. Each light introductory element 100 thus remains attached to the light guide sheet 11 at one of its ends 100.1.

[0041] The large sheet on which the light guide sheet 11 and each light introducing element 100 are formed comprises a flexible film and outer layers disposed on both sides of the flexible film. An adhesive or pressure-sensitive adhesive layer is disposed between the flexible film and each outer layer. The adhesive or pressure-sensitive adhesive layer has a refractive index different from that of the flexible film. This is because light rays propagate by total internal reflection within the flexible film, so that the term "light guide" refers to the assembly of the guide sheet and each light introducing element.

[0042] Each group 10 and each light introducing element 100 is described below.

[0043] In a non-limiting embodiment, the number of groups 10 is between 2 and 20.

[0044] Note that in the examples shown in Figures 7 to 13 and 15, only eight light introducing elements 100 are shown per group 10 (compared to Figures 2, 4 and 14, which show ten).

[0045] Each group 10 is configured to illuminate one area 110 (described below) within the light guide sheet 11 .

[0046] A group 10 may include one or more light introducing elements 100. In a non-limiting embodiment, a group includes between three and ten light introducing elements 100. In a non-limiting variant embodiment, a group includes ten light introducing elements 100. In the non-limiting example of FIGS. 2 and 4, the light guide 1 includes three groups 10, each including ten light introducing elements 100. In the non-limiting example of FIG. 3, the light guide includes six groups 10, each including five light introducing elements 100. Compared to the examples of FIGS. 2 and 4, the number of groups 10 is doubled, resulting in an equal number of light introducing elements 100 per group 10. For clarity, only one light introducing element 100 is labeled.

[0047] Each group 10 is associated with at least one light source 20. The at least one light source 20 is configured to emit light rays R (shown in FIGS. 6 and 8). The light rays R propagate by total internal reflection within each light introducing element 100 of the group 10, transmitting the light to the light guide sheet 11 adjacent to each light introducing element 100 and thus illuminating each area 11 of the light guide sheet 11. In a non-limiting embodiment, each group 10 is associated with multiple light sources 20. In another non-limiting embodiment, each group 10 is associated with a single light source 20. The latter non-limiting embodiment is considered a non-limiting example in the following description and in the non-limiting examples of FIGS. 2, 3, and 4.

[0048] As shown in FIG. 6, the light introductory element 100 (also referred to as a coupling bar 100, light bar 100, or simply bar 100) is configured to receive light rays R emitted by the light source 20, which propagate within the light introductory element 100 and are totally internally reflected. The light introductory element 100 has a rectangular or square cross section. The light introductory element 100 has a length Lg′, a width La′ (both shown in FIG. 8), and a thickness e (shown in FIG. 6). The thickness e is the same as the thickness e of the light guide 1. The light introductory element 100 has two ends 100.1, one of which is attached directly adjacent to the light guide sheet 11 and the other of which is configured to face the light source 20. The light rays R emitted by the light source 20 enter through one end 100.1 and are transmitted to the other end 100.1 and toward the light guide sheet 11. For reasons of clarity, only the end 100.1 of the light introducing element 1008 of one group 10 is labeled with a reference number.

[0049] 8 shows three groups 10 of eight light introducing elements, designated 1001 to 1008. As shown in FIG. 8, one light introducing element 100 in one group 10 is adjacent to at least one other light introducing element 100 in the group 10. The light introducing elements 100 at both ends of the group 10 (i.e., 1001 and 1008) are adjacent to only one other light introducing element 100 in the group 100, while the so-called intermediate light introducing elements 100 (i.e., 1002 to 1007) that are not located at both ends of the group 100 are adjacent to two other light introducing elements 100 in the group 10.

[0050] As shown in Figure 7, the light introducing elements 100 of the same group 10, when not bent, extend along the axis y and have different positions pj (j = 1 to N, where N is an integer) in the direction +Z. The further a light introducing element 100 is from the light source 20, the higher its position pj. Thus, as shown in the non-limiting example of Figure 8, the light introducing element 1008 has a position p8, while the light introducing element 1001 has a position p1.

[0051] If the light guide 1 is arranged, for example, on the front of a motor vehicle 2, the surface of each light introducing element 100 is perpendicular to an axis x, which should be noted, corresponds to the axis Ox of the vehicle.

[0052] As shown in FIG. 5, each light introducing element 100 includes: a main portion 100.2 extending along the axis y (i.e. in the first direction of the light guide sheet 11, which will be described later); - an end portion 100.3 extending along the axis z (i.e., in the second direction of the light guide sheet 11, which will be described later). The end portion 100.3 is connected to the light guide sheet 11. The two portions 100.2 and 100.3 are separated by a bend 100.4. The end portion 100.3 extends after the bend 100.4. In a non-limiting embodiment, the bend 100.4 is a right-angle bend. The length Lg' of the light introducing element 100 is the sum of the dimensions of the main portion 100.2 and the end portion 100.3.

[0053] Figure 5 shows the end portions 100.3, main portions 100.2, and bent portions 100.4 separating the end portions 100.3 of the light introducing elements 100 of one group 10. Figure 5 shows the end portions 100.3 of ten light introducing elements 100 in one group 10 and the light sources 20 associated with that group 110.

[0054] The light introducing elements 100 of the same group 10 have different lengths Lg'. For clarity, only the length Lg' of the light introducing element 1008 is labeled in FIG. 8 . Also, one light introducing element 100 of a group 10 has a different length Lg' from the other light introducing elements 100 of the same group 10. This allows the light introducing elements 100 to be bent so that the end portions 100.3 form a stack 103 with a flat entrance surface 103.1, as shown in FIG. 6 . The end portion 100.3 of the light introducing element 100 extends after the bent portion 100.4. In a non-limiting embodiment, the bent portion 100.4 is a right-angle bent portion.

[0055] Each light inlet element 100 thus comprises a bent portion 100.4. The entrance face 103.1 of the stack 103 is formed by one of the two ends 100.1 of each of the light inlet elements 100 in the group 10 (the end of the terminal portion 100.3).

[0056] 6, the light introducing elements 100 in each group 10 are bent so that their end portions 100.3 form a stack 103 of thickness E that is adapted to the light emitting surface of the light source 20. The thickness E is the sum of the thicknesses e of the light introducing elements 100 (whose end portions 100.3 form the stack 103). The stack 103 has an entrance surface 103.1, which is formed by the ends of the end portions 100.3 of each light introducing element 100 in the group 110 and is configured to receive light emitted by the light source 20.

[0057] 6 and 8, in a non-limiting embodiment, the light sources 20 associated with the group 10 are positioned facing the incident surface 103.1 of the stack 103. A light ray R of the light source 20 enters through the incident surface 103.1 and thus propagates within each light introducing element 100. The light ray R is totally reflected within each light introducing element 100 and redirected towards the light guide sheet 11 via each bent portion 100.4.

[0058] It should be noted that the farther the group 10 is from the light source 20, the greater the length Lg' of the light inlet element 100. Thus, the farthest light inlet element 1008 has the greatest length Lg', while the nearest light inlet element 1001 has the smallest length Lg'. In this way, a flat entrance surface 103.1 for the stack 103 can be obtained.

[0059] The light introducing elements 100 in the same group 10 have the same width La'.

[0060] When there are multiple groups 110, the light introduction elements 100 are arranged in the same manner for all groups 10, i.e. the light-introducing elements 100 are adjacent to one another and are bent at a bent portion 100.4 to form a stack 103 with a flat entrance surface 103.1; The further away a group 10 is from the light source 20, the greater the length Lg' of the light-introducing elements 100. The length Lg' of the light-introducing elements 100 thus gradually increases in the direction away from the light source 20. The light-introducing elements 100 furthest from the light source 20 thus have the maximum length Lg', while the light-introducing elements 100 closest to the light source 20 have the minimum length Lg'. In this way, a flat entrance surface 103.1 for the stack 103 can be obtained. The light-introducing elements 100 of the same group 10 thus have different lengths Lg'.

[0061] The light introducing elements 100 of one group 10 illuminating one area 110 have a different length Lg′ than the light introducing elements 100 of another group 10 illuminating another area 110 .

[0062] In particular, the light-introducing elements 100 at position pj of one group 10, which illuminate one area 110, have a different length Lg′ than the light-introducing elements 100 at the same individual position pj of another group, which illuminates another area 110. This allows the light sources 20 associated with each group 10 to be positioned further away from the light guide 1. As a result, the light sources 20 can be located at only one given location and arranged on a single electronic support 21, as shown in FIG. 8. Because only a single electronic support 21 is required, a single connector is required, thereby reducing the number of connectors. Reducing the number of connectors also reduces the number of associated electrical connection harnesses to a single electrical connection harness. In a non-limiting embodiment, the electronic support 21 is a PCBA (printed circuit board assembly). In a non-limiting example, each of the light sources 20 thus positioned further away is positioned between 10 and 50 centimeters from the light guide 10.

[0063] In application to a motor vehicle 3, this allows the light source 20 with the electronic support 21 to be installed remotely, behind the front where there is room, or behind the headlight or rear light where there is room. Thus, a high-luminous flux light source 20 adapted for use in a motor vehicle 3 and therefore larger than those of the prior art can be used. Thus, a heat sink 22 (shown in FIG. 8) suitable for dissipating the heat emitted by the high-power light source 20 can be used without space limitations. In a non-limiting embodiment, each light source 20 has a luminous flux of 400 lumens per light source 20. In a non-limiting embodiment, a fan (not shown) can also be used in addition to the heat sink 22 to cool the light source 20.

[0064] Because high power light sources 20 can be used, it is possible to have a large surface area light guide sheet 11 (described below) with multiple zones 110, thus allowing for efficient illumination of various zones 110. Thus, for example, the light guide 1 can be used for the front, headlights, or rear lights (which are spread over a large area) of a motor vehicle 3.

[0065] It should be noted that because the light-introducing elements 100 of one group 10 illuminating one area 110 have a different length Lg' than the light-introducing elements 100 of the other groups 10 illuminating the other areas 110, when each light-introducing element 100 is bent, its respective end portion 100.3 can have a different position along the axis y (when projected onto the axis y) from the other groups 10. This is in contrast to the prior art, in which all groups have the same position along the axis y (when projected onto the axis y). In the prior art, the entrance faces of the stacks are aligned along the axis z but are located at different heights above the axis z. In contrast, in the light guide 1 described, the entrance faces 103.1 of the stacks 103 are aligned along the axis y but are located at different positions above the axis y. In other words, the entrance faces 103.1 of the illustrated light guides are laterally offset from one another.

[0066] In a non-limiting embodiment, in the non-limiting example of FIG. 2 , where the light guide 1 includes three groups 10, the group 10 farthest from the light source 20 (also known as the third group 10) that illuminates one area 110 includes light-introducing elements 100 with lengths Lg′ that differ from the light-introducing elements 100 at the same position pj in the group 10 closest to the light source 20 (also known as the first group 10) that illuminates another area 110. In other words, the set of light sources can be considered a reference point located toward the bottom of the figure (generally the side that each light-introducing element faces when bent in the bending direction). The group farthest from the reference point illuminates the area located farthest from the reference point. In this case, the light-introducing elements of the farthest group each have a longer length than the light-introducing elements 100 at the same position pj in the groups 10 located closer to the reference point.

[0067] 8, the bar 1001 at position p1 of the third group 10 has a greater length Lg' than the bar 1001 at the same position p1 of the first group 10. Also, the bar 1008 at position p8 of the third group 10 has a greater length Lg' than the bar 1008 at the same position p8 of the first group 10. The same applies to the intermediate bars 1002 to 1007 at their respective positions p2 to p7. It is therefore clear that the entrance faces 103.1 of the stacks 103 of the two groups 10 are at different positions along the axis y.

[0068] The intermediate group 10 (also called the second group 10), which is located between two other groups 10 and illuminates a different area 110 from the other two groups 10, has light-introducing elements 100 with a length Lg' different from the light-introducing elements 100 at the same position pj of the nearest group 10. In particular, the bar 1001 at position p1 of the second group 10 has a longer length Lg' than the bar 1001 at the same position p1 of the first group 10. Also, the bar 1008 at position p8 of the second group 10 has a longer length Lg' than the bar 1008 at the same position p8 of the first group 10. The same applies to the intermediate bars 1002 to 1007, which are located at their respective positions p2 to p7. It is therefore clear that the entrance faces 103.1 of the stacks 103 are located at different positions along the axis y in the two groups 10.

[0069] In a non-limiting embodiment, the light introducing element 100 has a thickness e of about 50 μm (microns). In a non-limiting embodiment, the light introducing element 100 has a width La′ between 1 and 20 millimeters. In a non-limiting embodiment, the light introducing element 100 has a length Lg′ between 100 and 500 millimeters.

[0070] In a non-limiting embodiment, the light introducing elements 100 in one group 10 have a different width La′ than the light introducing elements 100 in the other groups 10. This allows each group 10 to illuminate a different area 110, and therefore to use different numbers and / or sizes of light sources 20.

[0071] Hereinafter, the light guide sheet 11 will be described.

[0072] As shown in FIGS. 2, 3, and 4, the light guide sheet 11 is a plurality of areas 110; at least one light emitting area 111 integrated within at least one area 110; It is equipped with:

[0073] Since the light guide 1 is sheet-like, flexible and transparent, the guide sheet 11 is also sheet-like, flexible and transparent. Since the guide sheet 11 is flexible, it can be flat or curved depending on the position where it is placed and the mechanical stresses to which it is subjected. In particular, the sheet is adapted to the front, headlights and rear lights of the motor vehicle 3.

[0074] A light guide sheet 11 is attached adjacent to each light introducing element 100. Each area 110 is configured to be illuminated by a different group 10 of light introducing elements 100. The different areas 110 are illuminated by groups 10 of light introducing elements 100 of different sizes due to different lengths Lg'.

[0075] The light guide sheet 11 also includes at least one light mixing area 112. Light exiting the same group 10 of light introducing elements 100 will be mixed in the light mixing area 112, thereby enabling uniform illumination of the light emitting area 111 in the corresponding area 110.

[0076] A given area 110 includes at least one light emitting area 111 .

[0077] The light emitting area 111 is the area through which the light generated by the light rays R of the light sources 20 of the group 10 leaves the light guide sheet 11. In particular, in the non-limiting example under consideration, the light leaves in the direction +x (i.e. parallel to the vehicle axis Ox) towards the outside of the front of the motor vehicle 2.

[0078] According to a non-limiting embodiment, the at least one light-emitting area 111 forms at least one pattern (also known as pattern 111). In a non-limiting example, the pattern 111 has dimensions of 30x30 centimeters. In a non-limiting example, the pattern 111 is a logo or part of a logo. In this case, an illuminated logo is obtained. In a non-limiting embodiment, the pattern is formed by a microstructure. Such a microstructure may generally, in a non-limiting example, have the form of an embossment or a relief, at which the light ray R is reflected. The microstructures are nanometer structures. In a non-limiting embodiment, the pattern 111 is identical to the manufacturer pattern described above. In this case, the pattern 111 covers the manufacturer pattern when the light guide 1 is placed on the front surface. Thus, the manufacturer pattern appears when the light source(s) 20 are activated.

[0079] In the non-limiting example of FIGS. 9 and 10, the light guide sheet 11 has three regions 110 and light emitting areas 111 incorporated into the three regions 110, respectively.

[0080] 9 shows a first non-limiting example in which the lighting pattern is a logo, where a first light emitting area 111 forms the L of the logo, a second light emitting area 111 forms the O and G of the logo, and a third light emitting area 111 forms the O of the logo.

[0081] 10 shows a second non-limiting example of an illumination pattern including a plurality of diamonds, circles, and squares, where a first light-emitting area 111 forms each diamond, a second light-emitting area 111 forms each circle, and a third light-emitting area 111 forms each square.

[0082] The assembly of light guide 1, light source 20, electronic support 21 and heat sink 22 forms a light emitting device 2 shown in Figures 11 to 15.

[0083] Thus, the light emitting device 2 - at least one light guide 1 as described above, - a plurality of light sources 20 arranged on at least one same electronic support 21; at least one heat sink 22; It is equipped with:

[0084] A group 10 of the light guide 1 is associated with one or more light sources 20. Another name for the assembly of a group 10 of light introducing elements 100 and the associated one or more light sources 20 is a light in-coupling body 13. A light in-coupling body 13 is thus associated with each section 110 of the light guide sheet 11. For reasons of clarity, only one light in-coupling body 13 is referenced in Figures 11 to 13.

[0085] In a non-limiting embodiment, each light source 20 is a solid-state light source. In a non-limiting embodiment, each solid-state light source is a portion of a light emitting diode or a laser diode. "Light emitting diode" refers to any type of light emitting diode, including, but not limited to, an LED (light emitting diode), an OLED (organic LED), an AMOLED (active matrix organic LED), or a FOLED (flexible OLED).

[0086] In a non-limiting embodiment, the light sources 20 are operable independently of one another. This allows each area 110 of the light guide sheet 11 to be illuminated independently of one another, thus creating animation. In this way, in the example of Figure 9, an animated illuminated logo can be created. In this way, in the example of Figure 10, a diamond, a circle, and a square can be alternately illuminated to create animation.

[0087] According to an exemplary embodiment, the number of light sources 20 is adapted to the dimensions (length Lg', width La', thickness e) of the light-introducing element 100 in one group 10. Thus, it is possible to have the same number of light sources 20 in each group 10 or to have different numbers of light sources 20 in each group 10. Likewise, it is possible to have light sources 20 of different dimensions in each group 10 or to have light sources 20 of the same dimensions in all groups 10. In the non-limiting example of the drawings, there are the same number of light sources 20 in each group 10 (i.e., only one in this case), and the light sources 20 are of the same dimensions. In a non-limiting example, if the light source 20 has an emitting area of ​​1 mm 2 In another exemplary embodiment, the number of light introducing elements 100 is adapted to the number of light sources 20 used to meet the desired brightness requirements.

[0088] 11, 12, and 13 show a first embodiment of the light emitting device 1, - the light-emitting device 1 comprises a single light guide 1, the groups 10 of light-introducing elements 100 in this light guide 1 are arranged on the same side of the light-guide sheet 11 and thus form a first set of light-introducing elements 100; the light sources 20 of all groups 10 are arranged on the same electronic support 21; 1 shows a first embodiment.

[0089] Since the groups 10 of light-introducing elements 100 are all arranged on the same side of the light guide sheet 11, the corresponding light sources 20 can be mounted on the same electronic support 21 since they are all arranged on the same side. Therefore, only one electronic support 21 is required. Therefore, a single heat sink 22 is used. Thus, in the first non-limiting embodiment, the light-emitting device 2 only has one heat sink 22. Of course, it would also be possible to have multiple electronic supports.

[0090] 11 and 12, there are three groups 10 and three light sources 20 associated with each of the three groups 10, and the three groups 10 are arranged on the same side 11.1 of the light guide sheet 11. In this non-limiting example, the light guide sheet 11 has three areas 110, with each group 10 illuminating a different area 110.

[0091] 11, the light sources 20 are arranged in the same plane on the same electronic support 21. Each light source 20 is thus located at the same distance d from the three entrance faces 103.1 of the three stacks 103 formed by the light-introducing elements 100 of each of the three groups 10.

[0092] Due to the presence of groups 10 with light-introducing elements 100 of different lengths Lg', there is a risk of non-uniformity between the groups 10. Indeed, the path taken by the light ray R is shorter in the group 10 closest to the light source 20 than in the other two groups 10 that are further away. For the farthest group 10, which has the longest light-introducing elements 100, there may therefore be a loss of efficiency in the light propagation. To maintain the efficiency of the light propagation, in a non-limiting embodiment of this first variant, a set of light sources 20 associated with a group 10 is powered with a different current than the other sets of light sources 20 associated with the other groups 10. It is recalled that a set may comprise one or more light sources 20, but in this case only a single light source 20 is included. Thus, in the non-limiting example shown in FIG. 11, the light sources 20 of a group 10 are powered with a different current than the light sources 20 of the other groups 10. This means that each section 110 of the light guide sheet has a specific current (here denoted i, i', i"). The farther a group 10 is located from the light source 20, the stronger the associated current i must be to maintain light propagation efficiency. Thus, current i" is the strongest and current i is the weakest. In a non-limiting example, current i" for the farthest group 10 is 260 mA, current i' for the middle group is 255 mA, and current i for the closest group 10 is 250 mA. Thus, overall illumination uniformity across all sections 11 of the light guide sheet 11 is ensured.

[0093] In a non-limiting embodiment of the first non-limiting embodiment variant shown in FIG. 12, the light-emitting device 2 also comprises at least one light collimator 23 associated with the light source 20. The at least one light collimator 23 is arranged between the light source 20 and the above-mentioned stack 103. In particular, the light collimator 23 is arranged facing the entrance surface 103.1 of the stack 103. In a non-limiting embodiment, the light collimator 23 is an optical lens. As shown in FIG. 12, the light-emitting device 2 comprises three light collimators 23 associated with the light sources 20 of the three groups 10 of the light-introducing element 100, respectively. Each light collimator 23 is arranged facing one of the stacks 103, in particular its entrance surface 103.1. The light collimators 23 allow for a reduction in light losses of the light source 20 and therefore an improvement in light transmission efficiency when the light-introducing element 100 has a small thickness e (1 to 5 mm). The light collimators 23 also serve as intermediate components between the light sources 20 and the entrance surface 103.1 of the stack 103. This makes it possible to avoid the light sources 20 being too close to the entrance surface 103.1, which might burn the latter. As each light source 20 is far from the light guide sheet 11, there is room to add such light collimators 23.

[0094] In a second non-limiting variant of the first non-limiting embodiment shown in FIG. 13, each light source 20 is arranged on a different plane than the other light sources 20 on the same electronic support 21 and is powered with the same current i. The electronic support 21 thus comprises steps, with each light source 20 located on a different step. Each light source 20 is thus located at a different distance (in this case d, d', d") from the three entrance faces 103.1 of the three stacks 103 described above. This allows for maintaining the efficiency of light transmission. The light source 20 associated with the group 10 furthest from each light source 20 is located at the shortest distance d". The light source 20 associated with the group 10 closest to each light source 20 is located at the longest distance d". In the non-limiting case of three light sources 20, in a non-limiting example, the light source 20 of the farthest group 10 is arranged at a distance d" of 0.4 mm (millimeters) from the entrance surface 103.1 of its corresponding stack 103. The light source 20 of the nearest group 10 is arranged at a distance d of 0.5 mm from the entrance surface 103.1 of its corresponding stack 103. Finally, the light source 20 of the middle group 10 is arranged at a distance d' of 0.45 mm from the entrance surface 103.1 of its corresponding stack 103. The distances d, d', d" of the light sources to the entrance surface 103.1 of the corresponding stack 103 are thus adjusted depending on the length Lg' of the light-introducing element 100, so that the light sources 20 are supplied with the same current i.

[0095] FIG. 14 shows a second embodiment of the light emitting device 1. - the light-emitting device 1 comprises a single light guide 1, a plurality of groups 10 of light-introducing elements 100 are arranged on a first side 11.1 of the light guide 11, thereby forming a first set of light-introducing elements 100, and a second set identical to the first set is arranged on a second side 11.2 of the light guide sheet 11 opposite the first side 11.1, so as to be symmetrical to the first set with respect to the light guide sheet 11; the light sources 20 associated with the first set are arranged on the same first electronic support 21, and the light sources 20 associated with the second set are arranged on the same second electronic support 21 (different from the first electronic support 21); It shows something.

[0096] Thus, in the non-limiting example of Figure 14, there are two sets of three groups 10: a first set of three groups 10 located on one side 11.1 of the light guide sheet 11, and a second set of three groups 10 located on the other side 11.2 opposite the first side 11.1. The light guide sheet 11 comprises two light mixing zones 112 facing each of the two sets of three groups 10. In the non-limiting example, the light guide sheet 11 comprises three regions 110. Each group 10 of a set illuminates a different region 110 than the other groups 10 of the same set. One group 10 of the first set illuminates the same region as another group 10 of the second set.

[0097] This second non-limiting embodiment allows for increased illumination of each zone 110 because there is illumination from both sides of the light guide sheet 11 instead of one side as in the first non-limiting embodiment. This allows for a reduction in the luminous flux of each light source 20, as there are two smaller heat sinks 22, which are less bulky than in the first non-limiting embodiment, where only a single heat sink 22 is provided in the non-limiting embodiment. In the illustrated non-limiting example, there are twice as many groups 10 as in the first non-limiting embodiment, and therefore twice as many light sources 20. The first non-limiting embodiment variant of the first non-limiting embodiment (where the light sources 20 are on the same plane) and the second non-limiting embodiment variant of the first non-limiting embodiment (where the light sources 20 are on different planes) can be applied (either alone or in combination) to the second non-limiting embodiment.

[0098] Figure 15 shows a third embodiment of a light-emitting device 1, which comprises at least two light guides 1 stacked oppositely. In the non-limiting example of Figure 15, the light-emitting device 1 comprises two light guides 1 as described in the second embodiment of Figure 14 (i.e., each comprising two pairs of groups 10 of light-introducing elements 100, each pair being arranged on one side 11.1 and the other opposite side 11.2 of the light guide sheet 11). The two light guides 1 are opposed to each other in that the entrance faces 103.1 of their stacks 103 are arranged along the two opposite sides 11.3 and 11.4, respectively. 15 it is thus clear that the two entrance faces 103.1 of the two stacks 103 in the first light guide 1 are arranged along the third side 11.3 of the light guide sheet 11, and the two entrance faces 103.1 of the two stacks 103 in the second light guide 1 are arranged along the fourth side 11.4 of the light guide sheet 11, said fourth side 11.4 being opposite the third side 11.3. In the illustrated non-limiting example, there are twice as many light sources 20 as in the second non-limiting embodiment, and thus four electronic supports 21 and four heat sinks 22. The light guide sheet 11 comprises four light-mixing zones 112 facing each of the two pairs of three groups 10 in each light guide 1. For reasons of clarity in the drawings, only a single light source 20 per electronic support 21 is referenced, and only four entrance faces 103.1 are referenced. In a non-limiting example, the light guide sheet 11 comprises three zones 110. Each zone 110 is illuminated by four groups 10. In particular, each zone 110 is illuminated by one group 10 of the first set and one group 10 of the second set in each light guide 11.

[0099] This third non-limiting embodiment makes it possible, for example, to create moving images with two superimposed patterns. Thus, in a non-limiting example, two light guides 1 are arranged on the rear lights (e.g., rear position lights) of a motor vehicle 3. In this case, the first light guide 1 may comprise a first light-emitting area 111 forming a first pattern, and the second light guide 1 may comprise a second light-emitting area 111 forming a second pattern (superimposed on the first pattern). When the position lights are switched on, the light sources 20 associated with the first light guide 1 are activated, thus illuminating the first pattern, whereas the light sources 20 associated with the second light guide 1 are deactivated, thus not illuminating the second pattern. When the driver applies the brakes, the light sources 20 associated with the second light guide 1 are activated, thus illuminating the second pattern as well, which may thus be superimposed on the first pattern if the two patterns are identical. When the driver applies the brakes, the light source 20 associated with the second light guide 1 is activated, thus also illuminating a second pattern, which may serve as an additional complement to the first pattern.

[0100] Of course, the description of the present invention is not limited to the above-mentioned embodiments or the above-mentioned fields. Thus, the present invention can be applied to any application, other than vehicle applications, that requires a large light-emitting surface. Thus, in a third variant of the first non-limiting embodiment, instead of having the light sources 20 on different planes in the steps of the electronic support 21 or supplying different currents to light sources 20 located on the same plane, the light sources 20 can be arranged on the same plane of the electronic support 21, with the positions of their entrance faces 103.1 offset relative to each other along the axis x. Their entrance faces 103.1 will no longer be aligned along the axis x. Thus, along the axis x, the entrance face 103.1 of the stack 103 of the group 10 furthest from the light source 20 will be closer than the other two, and the entrance face 103.1 of the stack 103 of the group 10 closest to the light source 20 will be farther away than the other two.

[0101] The described invention thus has the following advantages in particular: - allows the use of flexible surface light guides adapted to vehicle applications where large surface areas are to be illuminated; - allows the use of a light-emitting device 2 having a light source 20 with a luminous flux sufficient to illuminate the light guide sheet 11 of the light guide 1, - if all light sources 20 are located on the same side of the light guide sheet 11, it is possible to have only a single electronic support 21, thereby reducing the number of electronic supports compared to the prior art, and thus reducing the size, weight and cost of the light-emitting device 2; - reducing the number of electronic supports allows for a reduction in the number of associated connectors and a reduction in the number of associated electrical connection harnesses, thereby reducing the size, weight and cost of the light emitting device 2; - by moving each light source 20 away from the light guide sheet 11, it is possible to place each light source 20 in a spacious and unrestricted space, thus making it possible to use light sources 20 with a higher luminous flux than in the prior art, if desired, and also allowing the possibility to place one or more heat sinks 21 in the unrestricted space, adapted to the size and luminous flux of the light source 20, so that the size of the heat sink(s) may be increased with respect to the prior art; - making it possible to obtain a more efficient and intense illumination of the light guide sheet 11 and its respective zones 110; - it allows the light-emitting surface area (i.e. the total surface area of ​​the illuminated areas 110 of the light guide sheet 11) to be increased without reducing the efficiency of the illumination; - Allows the use of illuminated logos (which can be animated if necessary).

Claims

1. A flexible surface light guide (1) for a vehicle (3) comprising a plurality of groups (10) of light-introducing elements (100) and a light guide sheet (11), each group (10) being associated with at least one light source (20), - said light guide sheet (11) comprises a plurality of zones (110), at least one light emitting area (111) being integrated in at least one zone (110), said light guide sheet (11) being adjacent to said light introducing element (100), each group (10) being configured to illuminate one zone (110) in said light guide sheet (11); the light-introducing elements (100) of one group (10) illuminating one area (110) have a different length (Lg') than the light-introducing elements (100) of another group (10) illuminating another area (110); A light guide (1) characterized by:

2. 2. The light guide (1) according to claim 1, wherein in each group (10) of light introducing elements (100), the light introducing elements (100) are bent to form a stack (103) having a thickness (e) adapted to the light emitting surface (s1) of a given light source (20), and the stack (13) has a light entrance surface (103.1) configured to receive light emitted by the light source (20).

3. 3. The light guide (1) according to claim 2, wherein the dimensions of the light introducing elements (100) are determined so that when each of the light introducing elements in the group of light introducing elements is bent, the front writing surfaces (103.1) of each of the groups of light introducing elements are at the same height.

4. 10. The light guide (1) according to any one of the preceding claims, wherein the at least one light emitting area (111) forms at least one pattern.

5. A light guide (1) according to any one of claims 1 to 4, wherein a plurality of groups (10) of the light introducing elements (100) are arranged on the same side (11.1) of the light guide sheet (11) to form a first set of light introducing elements (100).

6. A light guide (1) according to any one of claims 1 to 4, wherein the groups (10) of light introducing elements (100) are arranged on a first side (11.1) of the light guide sheet (11) to form a first set of light introducing elements (100), and the light guide (1) has a second set identical to the first set, which is arranged on a second side (11.2) of the light guide sheet (11) opposite the first side (11.1) so as to be symmetrical to the first set with respect to the light guide sheet (11).

7. A light emitting device (2) for a vehicle (3), characterized in that it comprises at least one light guide (1) according to any one of the preceding claims, a plurality of light sources (20), and at least one heat sink (22).

8. 8. A light-emitting device (2) according to claim 7, wherein the light sources are arranged on the same electronic support (21).

9. 9. A light-emitting device (2) according to claim 8, wherein the light sources (20) are arranged on the same plane of the same electronic support (21).

10. 9. A light-emitting device (2) according to claim 8, wherein each light source (20) is arranged in a different plane than the other light sources (20) on the same electronic support (21).

11. 11. A light emitting device (2) according to any one of claims 7 to 10, wherein the light emitting device (2) comprises at least two light guides (1) stacked oppositely to one another.

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