Illumination device for a vehicle headlight as well as vehicle headlights

Description

[0001] The invention relates to a lighting device for a motor vehicle headlight for generating a light distribution with a light-dark boundary, wherein the lighting device comprising at least one light source, a translucent body, at least one light coupling element for coupling light emitted by the at least one light source into the translucent body, and a projection device, wherein the projection device comprises a focal surface and an optical axis. wherein light from at least one light source couples into the translucent body via the light coupling element, which propagates within the translucent body as the first light beam to a light emission surface of the translucent body, and wherein the translucent body is bounded by an upper boundary surface and a lower boundary surface opposite the upper boundary surface, wherein at least a portion of the light rays of the first light beam incident on the upper and / or lower boundary surface is totally reflected once or multiple times at the respective boundary surface, and wherein the translucent body is bounded by a light emission surface, and wherein the light rays totally reflected once or multiple times at the at least one boundary surface, which exit the body via the light emission surface, as well as those light rays coupled in from the light source,which propagate through the translucent body without reflection to the light-emitting surface and exit the body via this surface, are modified by the light-guiding body into a second light beam, which is imaged by the projection device as the light distribution to be generated.

[0002] The light emission surface is located, for example, opposite the light coupling element.

[0003] Furthermore, the invention relates to a motor vehicle headlight with at least one such lighting device.

[0004] Lighting devices described above are known from the prior art, in which, by modifying the translucent body, the light coupling element, or the projection device, a signlight light distribution can be generated in addition to a front or low beam light distribution with at least one light source. WO 2018 / 023141 A1 and WO 2023 / 0385010 A1 disclose lighting devices with a signlight light distribution.

[0005] With known solutions, the resulting signlight light distribution is relatively homogeneous. However, to achieve luminous intensity values, such as those legally required, at specific points in the light distribution, it is often necessary for the overall luminous intensity of the signlight distribution to be comparatively high. This, however, leads to luminous intensity values ​​at other points that are higher than desired or even higher than legally permitted.

[0006] It is an object of the invention to provide a lighting device with which, in addition to a front-end or low-beam light distribution, a signlight light distribution can be generated, thereby overcoming the aforementioned disadvantages. Furthermore, it can be an object of the invention to generate a signlight light distribution which specifically takes into account the characteristics of regulations in the USA, for example, the FMVSS 108 regulation.

[0007] This problem is solved with a lighting device described above by attaching, according to the invention, to or from...in the lower boundary surface at least a first optical output coupling structure and at least a second optical output coupling structure are provided, and wherein the optical output coupling structures are configured such that light from the first light beam striking an optical output coupling structure exits the transparent body, wherein the light exiting from the at least one first optical output coupling structure propagates to the projection device outside the transparent body in the form of a third light beam, and wherein the light exiting from the at least one second optical output coupling structure propagates to the projection device outside the transparent body in the form of a fourth light beam, wherein the at least one second optical output coupling structure is located further away from the focal surface than the at least one first optical output coupling structure, and wherein the third and fourth light beams are directly, i.e.without prior re-entry into the translucent body, strike the projection device and are projected by it as signlight light beams into an area above the light-dark boundary and together form, for example, a signlight light distribution, whereby the two signlight light beams are imaged into different sub-areas of the area above the light-dark boundary.

[0008] Preferably, exactly one first and exactly one second output structure are provided.

[0009] It can be provided that the at least one first and the at least one second optical output coupling structure each extend over a defined transverse extent perpendicular to the optical axis of the projection device, and wherein the at least one first and the at least one second optical output coupling structure each extend over a defined longitudinal extent approximately in the direction of the optical axis of the projection device.

[0010] The inventive design generates two different signlight light beams, which illuminate different areas in the light distribution and together form the signlight light distribution. By appropriately designing the different output structures, for example with regard to the size or extent of the respective output structure, the amount of light from the individual signlight light beams, and thus the luminous intensity in the light distribution, can be influenced. Due to the different distances of the output structures from the focal surface or the Petzval surface of the projection device, the light rays exiting the more distant output structure are rendered less sharply, i.e., "smeared," in the image and produce a more homogeneous illumination, while the light rays from the output structure closer to the Petzval surface or focal surface are rendered more sharply.The image is focused more sharply, thus illuminating a smaller area or smaller areas more brightly.

[0011] Advantageous embodiments of the invention are described in the dependent claims.

[0012] Preferably, the third and fourth light beams strike the projection device in different areas, particularly below an optical axis of the projection device, and pass through it, wherein these areas of the projection device project the third and fourth light beams as signlight light beams into the area above the light-dark boundary and, for example, form a signlight light distribution, wherein the two signlight light beams are imaged into different sub-areas of the area above the light-dark boundary.

[0013] In this case, the optical axis of the projection device also represents the optical axis of the lighting device.

[0014] It is advantageous if the at least one first optical output coupling structure and the at least one second optical output coupling structure are designed and arranged in such a way that the third and fourth light beams strike the projection device or an area of ​​the projection device in such a way that the partial areas into which the exiting signlight light beams are projected by the projection device either partially overlap, or at least adjoin each other in a section, or are spaced apart from each other.

[0015] It can be provided that the at least one first optical output coupling structure is designed as a raised area on or as a recess in the transparent body, and wherein the at least one second optical output coupling structure is designed as a raised area on or as a recess in the transparent body.

[0016] Furthermore, it can be provided that the at least one first and the at least one second optical output coupling structure have different transverse dimensions, wherein preferably the at least one first output coupling structure located closer to the light exit surface has a smaller transverse dimension than the at least one second output coupling structure.

[0017] In this way, the amount of light exiting the output coupling structures can be controlled.

[0018] It can be provided that at least one of the optical output coupling structures is symmetrical with respect to its transverse extent in relation to the optical axis of the projection device, wherein preferably a first or second optical output coupling structure is symmetrical and the other, second or first optical output coupling structure is asymmetrical with respect to the optical axis of the projection device.

[0019] A symmetrically arranged output structure provides a symmetrical illuminance distribution with respect to the vertical axis (VV axis) in the light pattern, while an asymmetrically arranged output structure produces an asymmetrical illuminance distribution with respect to the vertical axis. For example, in the USA, according to the FMVSS108 regulation, certain illuminance levels are prescribed along lines 5-5 and 8-8 as described in this regulation, where the position of these lines is asymmetrical with respect to the VV line. With a corresponding asymmetrical arrangement of an output structure, the required illuminance levels can also be achieved with respect to such asymmetrically positioned lines or areas. The basic signlight light distribution is symmetrical with respect to its illuminance distribution and is achieved with a symmetrical output structure.

[0020] Preferably, the transverse direction in which the at least one first and / or the at least one second optical output coupling structure extends(s) is / are essentially normal to the first direction of light propagation and / or normal to the optical axis of the projection device and preferably essentially horizontal.

[0021] Furthermore, it may be provided that at least one first and / or at least one second output structure is / are designed in the form of an output prism or has / have output prisms.

[0022] It may be provided that each coupling prism has an exit surface which is designed and inclined in such a way that the exiting light beams are directed into the area(s) of the projection device which project the third and fourth light beams as signlight light beams into the area above the light-dark boundary.

[0023] For example, it is provided that at least one exit surface or both exit surfaces are curved horizontally, i.e. in horizontal sections, in particular concavely curved, wherein preferably horizontal cutting curves resulting from the intersection of such a curved exit surface with horizontal planes have the form of a partial circle or follow the shape of the Petzval surface of the projection device.

[0024] It may be provided that, vertically, i.e. in vertical sections, at least one or preferably both exit surfaces are not curved.

[0025] Preferably, it is provided that an exit surface or the exit surfaces are inclined in such a way that the light beams passing through or exiting the exit surface or the exit surfaces run orthogonally onto the landing surface or the exit surfaces.

[0026] This can reduce losses and color errors.

[0027] By appropriately designing the light coupling element, a parallel beam fan can be shaped in such a way that the light rays strike the exit surfaces at an angle of 90°, as seen across the transverse extent of the exit surfaces.

[0028] Furthermore, it is preferably provided that the translucent body has an aperture edge which is arranged in the direction of light propagation between the light coupling element and the projection device, wherein the aperture edge is depicted in the light distribution as the light-dark boundary.

[0029] The aperture edge is responsible for modifying the first light beam into the second light beam emerging from the translucent object, such that the light distribution produced by the projection device exhibits a light-dark boundary. The shape of this boundary in the light distribution is determined by the shape of the aperture edge. The contour of the aperture edge defines the limiting rays that contribute to the overall light distribution.

[0030] The aperture edge is formed by the light exit surface and the lower boundary surface, i.e. the two surfaces meet at the aperture edge.

[0031] Furthermore, it can be provided that the light coupling element shapes the light emitted from the light source and coupled into the light coupling element into the first light beam, preferably directing the light beam into an area, in particular into an area above, preferably just above, the aperture edge.

[0032] This area lies or extends particularly just above the edge of the aperture.

[0033] Preferably, the aperture edge is curved in the horizontal direction, in particular concavely curved, and preferably follows the focal line of the projection device of the aperture edge, wherein preferably the aperture edge lies in or approximately in the Petzval surface of the projection device.

[0034] Regarding the statement that the aperture edge lies within the Petzval surface, it should be noted that, strictly speaking, the relationships are as follows: the projection device has a focal point which lies on the optical axis of the projection device. The Petzval surface, or focal point surface, contains this focal point, just as a focal line passes through this focal point and lies within the Petzval surface.

[0035] The aperture edge is usually not located exactly on the Petzval surface or at the focal point, but at a (slight) distance above it. Typically, the light-dark boundary in the image is lowered slightly below the horizontal 0°-0° line or below the horizon, usually by 0.573°. To achieve this in the image, the aperture edge is positioned slightly above the optical axis of the projection device or above the focal point in the vertical direction, in practice usually by a few tenths of a millimeter.

[0036] Furthermore, it can be provided that the light emission surface is concave in the horizontal direction and preferably follows the shape of the Petzval surface of the projection device.

[0037] It is also possible for the light-emitting surface to be convex in the vertical direction. In this embodiment, the light-emitting surface is inclined away from the Petzval surface, starting from the aperture edge. The resulting light distribution is somewhat smeared, meaning it is more homogeneous, and the height of the projection device can be reduced.

[0038] For example, it is intended that at least one light source and / or the signlight light source each includes one or more light-emitting elements, e.g. one or more LEDs.

[0039] The invention is discussed in more detail below with reference to the drawing. This drawing shows Fig. 1the essential components of an embodiment of a lighting device for a motor vehicle headlight according to the invention in a perspective view from a low angle, Fig. 1a a translucent body of the lighting device made of Figure 1 for beam shaping in a perspective view from obliquely below onto inventive coupling structures, Fig. 2 a vertical section through the lighting device Figure 1 along a vertical plane which passes through the optical axis of the projection device, Fig. 2a a vertical section through an alternative lighting device, Fig. 3 A detailed view of the first coupling structure in a perspective view from below, Fig. 4 a detailed view of the first output structure from Figure 3 in a top view from below, Fig. 5a vertical section normal to the optical axis through the translucent body in the area of ​​the second output coupling structure in a front view, Fig. 6 a section along line AA Figure 5 , Fig. 7 an exemplary, schematic representation of a light distribution in the form of a low beam distribution and a signlight light distribution, and Fig. 8 An exemplary representation of a light distribution as a result of a lighting simulation.

[0040] The Figure 1, 1a and 2 They show a lighting device 1 for a motor vehicle headlight for generating a light distribution LV with a light-dark boundary HDG, wherein the light distributions achievable with this lighting device 1 are in Figures 7 and 8 are shown schematically, whereby Figure 8 A light distribution is shown as a simulation result using a lighting device according to the invention.

[0041] Figure 2a Figure 1 shows an alternative embodiment of a lighting device according to the invention. The same reference numerals are used as in the figures shown. Figures 1, 1a and 2 They denote the same elements.

[0042] The Figures 3 - 6 Show details of the lighting device 1, which apply to both embodiments.

[0043] A lighting device 1 according to Figure 1, 1a and 2 or according to Figure 2aThe system comprises a light source 10, a translucent body 100, a light coupling element 101 for coupling light emitted by the light source 10 into the translucent body 100, and a projection device 500, wherein the projection device 500 has a focal surface or Petzval surface P500. The projection device 500 is typically implemented as a projection lens, but can also have a more complex structure in the form of a lens system. The Petzval surface P500 also contains the focal line of the projection device 500, on which the focal points of the projection device 500 lie in a horizontal plane.

[0044] For example, the translucent body 100 and the light coupling element 101 are formed in one piece and preferably from the same material. The projection device 500 is preferably designed separately from these elements 100 and 101. The body 100, the light coupling element 101, and the projection device 500 can be made from the same material.

[0045] The transparent, translucent material from which bodies 100, 101, and 500 can be formed has a refractive index greater than that of air. The material contains, for example, PMMA (polymethyl methacrylate) or PC (polycarbonate) and is preferably formed from these materials. However, the bodies can also be made of glass material, particularly inorganic glass material.

[0046] Light S10 is introduced via the light coupling element 101 ( Figure 2 , 2aThe light emitted by the light source 10 is coupled into the transparent body 100 via a light-entry surface 101a of the transparent body 100. The coupling element 101 can, for example, have the form of an imaging or non-imaging collimator optic. The light coupling surface 101a is configured accordingly; the planar light coupling surface 101a shown or indicated in the figures is merely one of several known possibilities for the configuration of the light coupling surface 101a.

[0047] The light source, or generally the at least one light source, consists, for example, of one or more light-emitting elements, e.g., one or more LEDs, which are encompassed by the light source or the at least one light source.

[0048] The translucent body 100 is bounded, among other things, by an upper boundary surface 105 and a lower boundary surface 106 opposite the upper boundary surface 105, as well as by a light emission surface 102, 102" opposite the light entry surface 101a.

[0049] The coupled light from the light source 10 propagates in the translucent body 100 essentially in the direction of the light exit surface 102 as the first light beam S1, wherein the light coupling element 101 forms the light emitted by the light source 10 and coupled into the light coupling element 101 into the first light beam S1.

[0050] The coupled light moves partly without deflection, and partly as a result of total internal reflection at boundary surfaces, in particular at the upper boundary surface 105 and / or lower boundary surface 106, in the translucent body 100 as a light beam S1 in the direction of the light exit surface 102.

[0051] The translucent body 100 has an aperture edge 104, which is arranged in the direction of light propagation between the light coupling element 101 and the projection device 500, wherein the aperture edge 104 is represented in the light distribution LV as a light-dark boundary HDG (see Figure 7 and Figure 8 ).

[0052] The aperture edge 104 is responsible for modifying the first light beam S1 into the second light beam S2 emerging from the translucent body 100, such that the light distribution LV generated by the projection device 500 from the light rays of light beam S2 exhibits a light-dark boundary HDG. The shape of the light-dark boundary in the light distribution LV is determined by the shape and contour of the aperture edge 104.

[0053] The aperture edge 104 is formed by the light exit surface 102 and the lower boundary surface 106, i.e. the two surfaces 102, 106 meet at the aperture edge 104.

[0054] The light coupling element 101 and the light-transmitting body 100 are shaped such that the first light beam S1 is directed towards the light exit surface 102, preferably but mainly into a region P0, in particular a region, preferably just above, the aperture edge 104, resulting in a sharp light-dark boundary HDG with a high illuminance below the light-dark boundary in the light distribution LV.

[0055] Preferably, the aperture edge 104 is curved in the horizontal direction, in particular concavely curved, as shown, and preferably follows the focal point line F500 of the projection device 500 in the aperture edge 104.

[0056] Preferably, the aperture edge 104 is located in or approximately in the Petzval surface P500 of the projection device 500, as already explained in the introduction.

[0057] Furthermore, as is the case with lighting device 1 according to the Figures 1, 1a and 2 In this case, the light-emitting surface 102 is convex in the vertical direction. In this embodiment, the light-emitting surface 102 is thus inclined away from the Petzval surface P500, towards the light source 10, starting from the aperture edge 104. The resulting light distribution LV is somewhat smeared, i.e., the resulting light distribution is more homogeneous, and the height of the projection device 500 can be reduced.

[0058] Alternatively, see Figure 2a - provided that the light emission surface 102" is concave in the horizontal direction and preferably follows the shape of the Petzval surface P500 of the projection device 500.

[0059] Specifically, the light rays propagating towards the light exit surface 102, 102" and exiting the body 100 via this surface are modified by the light-guiding body 100, in particular also by the aperture edge 104, to a second light beam S2, which is imaged by the projection device 500 as a light distribution LV with the light-dark boundary HDG.

[0060] How the Figures 1, 1a , 2 and 2aAs can be further seen, a first optical output structure 210 and a second optical output structure 220 are provided on or in the lower boundary surface 106. Each optical output structure 210, 220 extends over a defined transverse extent Q 210 , Q 220 transverse to the optical axis X of the projection device 500 or the illumination device 1, respectively. Each optical output structure 210, 220 extends over a defined longitudinal extent L 210 , L 220 approximately in the direction of the optical axis X.

[0061] For the sake of clarity, it should be noted here that, in principle, two or more first and two or more second coupling structures can also be provided, which are then preferably arranged side by side (first structures next to each other, second structures next to each other).

[0062] The optical output coupling structures 210, 220 are designed such that light from the first light beam S1, which hits an optical output coupling structure 210, 220, exits the transparent body 100.

[0063] The light exiting the first optical coupling structures 210 propagates in the form of a third light beam S3 outside the translucent body 100 to the projection device 500.

[0064] The light exiting the second optical coupling structure 220 propagates in the form of a fourth light beam S4 outside the translucent body 100 to the projection device 500.

[0065] The second optical output coupling structure 220 is located further away from the focal surface P500 than the first optical output coupling structures 210.

[0066] The arrangement is such that the third and fourth light beams S3, S4 strike the projection device 500 directly, i.e. without prior re-entry into the translucent body 100, and are projected by it as signlight light beams S3', S4' into an area B lying above the light-dark boundary HDG and together form a signlight light distribution SV, wherein the two signlight light beams S 3 ', S 4 ' are imaged into different sub-areas B1, B2 of the area B lying above the light-dark boundary HDG.

[0067] Light S4, which originates from the output coupling structure 220 located further away from the focal surface P500, produces a blurred or less sharp image due to its (strongly) defocused position and thus better homogeneity with approximately the same illuminance in the generated light distribution SV4 compared to the light distribution SV3 produced by the light rays S3 of the first output coupling structures 210 located closer to the focal surface P500.

[0068] The light distribution SV4, generated by the coupling structure 220 located further away from the focal surface P500, forms a kind of "basic" signlight distribution, which, for example, meets the requirements for a signlight light distribution according to ECE. The other light distribution SV3 forms a kind of "additional" signlight light distribution, with which further requirements for the signlight, exceeding those of ECE, can be met and / or it allows the "basic" signlight light distribution SV4 to be modified, for example, with regard to the generated illuminance, so that certain required limit values ​​are reached, but together with the additional signlight light distribution SV3, a signlight light distribution SV, which is particularly compliant with laws or regulations, can still be generated.

[0069] Preferably, the third and fourth light beams S3, S4 are directed onto the projection device 500 in different areas P1, P2 of the projection device 500, in particular below an optical axis X of the projection device 500, and pass through it, wherein these areas of the projection device 500 project the third and fourth light beams S3, S4 as signlight light beams S3', S4' into the area B lying above the light-dark boundary HDG and form, for example, the signlight light distribution SV, wherein the two signlight light beams S3', S4' are imaged as described into different sub-areas B1, B2 of the area B lying above the light-dark boundary HDG.

[0070] The first optical output coupling structure(s) 210 and the second optical output coupling structure 220 are preferably designed and arranged such that the third and fourth light beams S3, S4 strike the projection device 500 or in a region P1, P2 of the projection device 500 in such a way that the sub-regions B1, B2, into which the exiting signlight light beams S3', S4' are projected by the projection device 500, either partially overlap, or at least adjoin each other in a section, or are spaced apart from each other.

[0071] Figure 8This shows exemplary simulation results. Sub-area B1 is located slightly to the right of the vertical 0° axis, just above the light-dark boundary, and is relatively concentrated. Sub-area B2, located above it, is symmetrical to the vertical 0° axis and significantly less concentrated than sub-area B1, meaning it extends over a considerably larger angular range in both the horizontal and vertical directions. The upper edge of sub-area B1 merges with the lower edge of sub-area B2. The overall signlight distribution SV results from the sub-signlight light distributions SV3 and SV4, which are mapped to sub-areas B1 and B2, respectively, and can be described by SV = SV(S3') ∪ SV(S4').

[0072] In the embodiment shown (which is for Figure 2 and Figure 2a(identical) the first optical output coupling structures 210 are formed as a raised area on the translucent body 100, specifically on the underside 106, and the second optical output coupling structure 220 is also formed as a raised area on the translucent body 100, again on the underside 106.

[0073] The in Figure 7 and Figure 8 The signlight light distributions SV3 and SV4 shown (with significantly different horizontal extents) are achieved by using the first and second optical output coupling structures 210 and 220, as shown in Figure 1aThe first output coupling structure 210, located closer to the light exit surface 102, has a smaller transverse extent Q210 than the second output coupling structure Q220. This allows the amount of light exiting the output coupling structures to be controlled. Furthermore, the second output coupling structure 220 is arranged symmetrically with respect to the optical axis X, while the first output coupling structure 210 is shifted to the left with respect to the optical axis X and is preferably located entirely to the left of the optical axis X.

[0074] In the illustrated embodiment, the second output coupling structure 220 extends continuously from left to right over essentially the entire width of the light-transmitting or light-guiding body 100; the extent to both sides of the optical axis X is identical.

[0075] Regardless of the specific number of first and second output structures 210, 220 and the arrangement with respect to the optical axis X, it is preferably provided that the (partial) signlight light distribution SV4 of the light beams S4 is symmetrical with respect to a vertical 0°-0° line (VV line) in the light pattern, while preferably the (partial) signlight light distribution SV3 of the light beams S3 is asymmetrical with respect to the vertical 0°-0° line (VV line, vertical center line at H = 0°) in the light pattern and is shifted to the right in the case of headlights for right-hand traffic, and would be shifted to the left in the case of headlights for left-hand traffic.

[0076] Returning once again to the Figure 1aas well as 3 - 6 it can be seen that it is preferably provided that the transverse direction in which the first and second optical output coupling structure 210, 220 extend is essentially normal to the optical axis X of the projection device 500 and essentially horizontal.

[0077] Looking at the output coupling structures 210, 220 in detail, they are preferably each designed approximately in the form of an output coupling prism, as shown. The output coupling prisms each have an exit surface 210a, 220a, which is inclined such that the exiting light beams S3, S4 are directed into the areas P1, P2 of the projection device 500, which projects the third and fourth light beams S3, S4 (signlight light beams S3', S4') into the area B lying above the light-dark boundary HDG.

[0078] In contrast to the prismatic shape, the exit surfaces 210a, 220a are horizontally curved, i.e., in horizontal sections, and in particular concavely curved, wherein preferably horizontal section curves resulting from the intersection of such a curved exit surface 210a, 220a with horizontal planes have the shape of a partial circle or follow the shape of the Petzval surface of the projection device. Figure 4Figure 1 shows a selected intersection curve in a horizontal sectioning plane, where the intersection curve represents a partial circle with center M and radius R. In different horizontal sectioning planes, the intersection curves can have identical radii, and their centers can lie on a (vertical) line; however, it is also possible for the radii to differ in different horizontal sectioning planes, and in particular, for the radii to increase when moving from the outermost horizontal sectioning plane towards body 100. The centers preferably lie on a vertical line, so the partial circles in different horizontal sectioning planes are, in effect, "concentric" partial circles.

[0079] Furthermore, it is preferably provided that, vertically, i.e., in vertical sections, both exit surfaces 210a, 220a are not curved. The intersection curves resulting from the intersection of the exit surfaces 210a, 220a with vertical planes are therefore straight lines.

[0080] Furthermore, it is preferably provided that the exit surfaces 210a, 220a are inclined to the optical axis X by an angle such that the S 3 , S 4 passing through or exiting the optical axis run orthogonally onto the flat surface 210a, 220a.

[0081] Finally, we would like to reiterate: Figure 7 Reference is made to which illuminance measurement points are used for the regulation of signlight light distributions according to FMVSS108 and the differences to regulations for the ECE area.

[0082] In the diagonally hatched area where lines 5-5 and 8-8 are located, there are differences regarding the required or maximum permitted illuminance of the signlight light distribution; in particular, according to the FMVSS108 regulation, the illuminance along these two lines must be higher than required by the ECE regulation.

[0083] In Figure 8 As described above, an actual light distribution is shown utilizing the output coupling structures 210, 220 according to the invention. Area B2 is illuminated uniformly from left to right via the "rear" output coupling elements 220. The output coupling structure 210, mounted on the left side only, illuminates the asymmetrically right-hand area B1 and compensates for the differences between US and European regulations.

Claims

1. Lighting device (1) for a motor vehicle headlight for generating a light distribution (LV) with a cut-off line (HDG), wherein the lighting device comprises • at least one light source (10), • a light-transmissive body (100), • at least one light coupling element (101) for coupling light emitted by the at least one light source (10) into the light-transmissive body (100), and • a projection device (500), wherein the projection device (500) has a focal surface (P500) and an optical axis (X), wherein light (S10) from the at least one light source (10) is coupled into the light-transmissive body (100) via the light coupling element (101), which propagates in the light-transmissive body (100) as a first light beam (S1) to a light exit surface (102) of the light-transmissive body (100), and wherein the light-transmissive body (100) is bounded by an upper boundary surface (105) and a lower boundary surface (106) opposite the upper boundary surface (105), wherein at least some of the light rays of the first light beam (S1) incident on the upper and / or lower boundary surface (105, 106) are totally reflected once or several times at the respective boundary surface (105, 106), and wherein the light-transmissive body (100) is bounded by the light exit surface (102, 102"), and wherein the light beams that are totally reflected one or more times at the at least one boundary surface (105, 106) and exit the body (100) via the light exit surface (102, 102") from the body (100), as well as those light beams coupled in from the light source (10) which propagate without reflection through the light-transmissive body (100) to the light exit surface (102, 102") and exit the body (100) via this surface, is modified by the light-conducting body (100) into a second light beam (S2), which is imaged by the projection device (500) as the light distribution (LV) to be generated, characterized in that at least one first optical coupling structure (210) and at least one second optical coupling structure (220) are provided on or in the lower boundary surface (106), wherein the optical coupling structures (210, 220) are designed such that light from the first light beam (S1) that strikes an optical coupling structure (210, 220) exits the light-transmissive body (100), wherein the light emerging from the at least one first optical coupling structure (210) propagates outside the light-transmissive body (100) in the form of a third light beam (S3) to the projection device (500), and wherein the light emerging from the at least one second optical coupling structure (220) propagates in the form of a fourth light beam (S4) outside the light-transmissive body (100) to the projection device (500), wherein the at least one second optical coupling structure (220) is further away from the focal surface (P500) than the at least one first optical coupling structure (210), and wherein the third and fourth light beams (S3, S4) strike the projection device (500) directly, i.e., without first re-entering the light-transmissive body (100), and are projected by the latter as sign light beams (S3', S4') into an area (B) located above the light-dark boundary (HDG) and together form a signlight light distribution (SV), wherein the two signlight light beams (S3', S4') are projected into different sub-areas (B1, B2) of the area (B) located above the light-dark boundary (HDG).

2. Lighting device according to claim 1, wherein the third and fourth light beams (S3, S4) strike the projection device (500) in different areas (P1, P2) of the projection device (500), in particular below an optical axis (X) of the projection device (500), and pass through it, wherein these areas of the projection device (500) form the third and fourth light beams (S3, S4) as signlight light beams (S3', S4') in the area (B) above the light-dark boundary (HDG) and form the signlight light distribution (SV), wherein the two signlight light beams (S3', S4') are imaged in different sub-areas (B1, B2) of the area (B) located above the light-dark boundary (HDG).

3. Lighting device according to one of the preceding claims, wherein the at least one first optical coupling structure (210) and the at least one second optical coupling structure (220) are designed and arranged such that the third and fourth light beams (S3, S4) strike the projection device (500) or an area (P1, P2) of the projection device (500) in such a way that the sub-areas (B1, B2) into which the emerging Signlight light beams (S3', S4') are projected by the projection device (500) either partially overlap, or at least adjoin each other in one section, or are spaced apart from each other.

4. Lighting device according to one of the preceding claims, wherein the at least one first optical coupling structure (210) is formed as a raised portion on or as a recess in the light-transmissive body (100), and wherein the at least one second optical coupling structure (220) is formed as a raised portion on or as a recess in the light-transmissive body (100).

5. Lighting device according to one of the preceding claims, wherein the at least one first and the at least one second optical coupling structure (210, 220) each extend transversely across a defined transverse extension (Q210, Q220) transverse to the optical axis (X) of the projection device (500), and wherein the at least one first and the at least one second optical coupling structure (210, 220) each extend over a defined longitudinal extent (L210, L220) approximately in the direction of the optical axis (X) of the projection device (500).

6. Lighting device according to claim 5, wherein the at least one first and the at least one second optical coupling structure (210, 220) have a different transverse extent (Q210, Q220), wherein preferably the at least one first coupling structure (210) located closer to the light exit surface (102) has a smaller transverse extension (Q210) than the at least one second coupling structure (Q220).

7. Lighting device according to claim 5 or 6, wherein at least one of the optical coupling structures is symmetrical with respect to the optical axis (X) of the projection device (500) in terms of its transverse extension, wherein preferably a first or second optical coupling structure (220) is symmetrical and the other, second or first optical coupling structure (210) is asymmetrical with respect to the optical axis (X) of the projection device (500).

8. Lighting device according to one of claims 5 to 7, wherein the transverse direction in which the at least one first and / or the at least one second optical coupling structure (210, 220) extends or extend is essentially normal to the optical axis (X) of the projection device (500) and preferably essentially horizontal.

9. Lighting device according to one of the preceding claims, wherein the at least one first and / or the at least one second coupling structure (210, 220) is or are designed in the form of a coupling prism or has or have coupling prisms.

10. Lighting device according to claim 9, wherein each decoupling prism has an exit surface (210a, 220a) which is designed and inclined in such a way that the exiting light beams (S3, S4) are directed into the area or areas of the projection device (500) which project the third and fourth light beams (S3, S4) as signal light beams (S3', S4') into the area (B) above the light-dark boundary (HDG).

11. Lighting device according to claim 9 or 10, wherein at least one exit surface (210a, 220a) or both exit surfaces (210a, 220a) are curved horizontally, i.e., in horizontal sections, in particular concave, wherein preferably horizontal section curves resulting from intersecting such a curved exit surface (210a, 220a) with horizontal planes have the shape of a partial circle or follow the shape of the Petzval surface (F500) of the projection device (500).

12. Lighting device according to one of claims 9 to 11, wherein vertically, i.e., in vertical sections, at least one or preferably both exit surfaces (210a, 220a) are not curved.

13. Lighting device according to one of claims 9 to 12, wherein an exit surface (210a, 220a) or the exit surfaces (210a, 220a) are inclined in such a way that the light beams (S3, S4) passing through or emerging from the exit surface (210a, 220a) or the exit surfaces (210a, 220a) pass through or emerge from the exit surface or exit surfaces run orthogonally to the entrance surface or exit surfaces.

14. Lighting device according to one of the preceding claims, wherein the light-transmissive body (100) has an aperture edge (104) which is arranged in the light propagation direction between the light coupling element (101) and the projection device (500), wherein the aperture edge (104) is depicted in the light distribution (LV) as the light-dark boundary (HDG).

15. Lighting device according to one of the preceding claims, wherein the light coupling element (101) forms the light emitted by the light source (10) and coupled into the light coupling element (101) into the first light beam (S1), wherein the light beam (S1) is preferably directed into a defined area (P0) of the aperture edge (104).

16. Lighting device according to one of the preceding claims, wherein the aperture edge (104) is curved in the horizontal direction, in particular concavely curved, and preferably follows the focal line (F500) of the projection device (500) in the aperture edge (104), wherein the aperture edge (104) is preferably located in the Petzval surface (P500) of the projection device (500).

17. Lighting device according to one of the preceding claims, wherein the light exit surface (102") is concave in the horizontal direction and preferably follows the shape of the Petzval surface (P500) of the projection device (500).

18. Lighting device according to one of claims 1 to 17, wherein the light exit surface (102) is convex in the vertical direction.

19. Motor vehicle headlight with at least one lighting device according to one of claims 1 to 18.