MOTOR VEHICLE EQUIPPING A MOTOR VEHICLE HEADLIGHT WITH A LIGHTING SYSTEM

Description

[0001] The invention relates to a motor vehicle with a motor vehicle headlight having a lighting system comprising at least two light sources, at least two light guides, at least one downstream light-transmitting radiating element, and at least one control unit for staggered control of the at least two light sources. The at least two light sources are configured to couple light into a respective light guide, the light guides each having at least one light output section configured to couple light into a light input section of the radiating element. Preferably, each light source is assigned a respective light guide.

[0002] Lighting systems are known from the prior art in which individual light sources can be controlled independently of one another, with the light emitted by the individual light sources being radiated or directed in a desired direction by light guides arranged next to one another. The light sources are controlled in such a way that the temporal progression of the amount of light emitted by the light sources is selected such that the impression of a moving light image or a light distribution (or appearance), a so-called running light, is obtained, and a running light effect can thereby be achieved. Such a lighting system or a method suitable for it is known, for example, from WO 2013 / 120124 A2. In this system, light guides radiate in a common radiation direction or couple light in this direction, with individual light guides being offset from one another perpendicular to the radiation direction.The offset between the light guides creates dark, less intensely illuminated areas in the light pattern of such a lighting system, which impairs the impression of a smooth transition between the light beams emitted by the light guides, since the individual light guides are recognizable as such. Document DE 1012014205996 A1 shows a direction indicator. Document US 4208363 shows a method for producing adjacent light guides. Document US 5001306 shows an optical device comprising a number of optical fibers.

[0003] WO 2013120124A2 shows a light guide structure. Document US 5184883 shows a lighting system comprising light guides and light sources.

[0004] It is therefore an object of the invention to provide a motor vehicle with a lighting system which is inexpensive and easy to manufacture, has a high mechanical strength and provides a consistently homogeneous light image which is improved compared to the prior art.

[0005] This object is achieved in a first aspect of the invention with a motor vehicle having a lighting system according to claim 1.

[0006] This makes it possible to place the light guides close to one another and to radiate the light emitted by the individual light guides via the radiating element. The light guides can preferably be placed at a constant distance behind the radiating element without the light guides having to be significantly bent along their longitudinal extent. Each light guide has a light output section that is assigned to a region of the light input section of the radiating element. This makes it possible to achieve an extremely robust and compact design of a lighting system that is particularly well suited to generating a running light by enabling a smooth transition between the light patterns generated by the light guides, so that designs can be achieved that are not feasible with a single light guide. For example,It is possible to arrange the light guides in a plane oriented parallel to the light guide's emission direction, allowing individual light guides to be arranged one behind the other, counter to the emission direction. The light coupling section and a light exit surface of the emission element can each have a stepped profile, thus preventing lateral offset of individual light beams.

[0007] The term "time-shifted control" refers to a control or regulation system capable of applying different signals to individual light sources. Apart from a temporal offset, the signals can have the same profile or be completely different. Examples of possible control signals and the resulting light patterns or light intensities of individual light sources can be found in WO 2013 / 120124 A2. For the purposes of the present invention, a light guide is understood to be a structure in which incident light is reflected by total internal reflection along the length of the light guide. Such a light guide can be designed as a solid body. In this context, it is preferred that the light guide be made of a transparent, colorless plastic.Alternatively, it can be made of glass or any other material suitable for light conduction, such as silicone. The radiating element can also be designed as a solid body and made of, for example, plastic, glass, silicone, or any other material suitable for light conduction. LEDs are preferably suitable as light sources. Alternatively, any other light sources known to those skilled in the art, such as incandescent lamps, xenon lamps, etc., can also be used.

[0008] It may be advantageous if the light guides have two straight legs connected to each other by a curved section, with the straight legs forming an angle of at least 60° to each other. This enables a particularly compact design of the lighting system according to the invention.

[0009] The light guides are designed as light rods. Light rods exhibit good light-guiding properties while requiring little space and offering good mechanical strength, making them particularly well-suited as light guides. The diameter of the light rods can preferably be between 6 mm and 10 mm. The light rods have optically effective imperfections in the light-outcoupling section, which are designed to deflect light propagating along the light rod such that the light exits the light rod through the light-outcoupling section and enters the light-incoupling section of the radiating element. The imperfections can preferably be designed as prisms or prism-like projections / recesses within the light rod.

[0010] In order to obtain a particularly simple and robust construction of the invention, it is provided that the radiating element is designed in one piece.

[0011] Furthermore, the radiating element is intended to have a continuous light-emitting surface. A continuous light-emitting surface is defined as a light-emitting surface defined by edges that, apart from the corners, have a continuous profile.

[0012] A particularly compact design of the invention can be achieved if the number of optical fibers exceeds the number of stages by one. Therefore, n+1 optical fibers are assigned to a number of n stages.

[0013] It is advantageous to use at least three light guides, which allows for a particularly high-resolution image. The number of light guides or stages can be exactly three, four, five, six, or more.

[0014] In order to ensure sufficient distance between the light guides and at the same time to bring the light output surfaces of the light guides as close as possible to the light input surfaces of the radiating element, it can be provided that the height h of each step is greater than the diameter of a corresponding light guide.

[0015] Preferably, the individual light guides can run essentially parallel to each other, at least in sections. This allows for a particularly compact design of the lighting system. The term "essentially parallel" refers to an alignment of the light guides that deviates from each other by a maximum angle of 5°. Preferably, the deviation in the alignment of individual light guides from each other is a maximum angle of 1°.

[0016] In order to prevent unwanted light coupling between the individual light guides, it can be provided that aperture elements are arranged between the light guides.

[0017] In addition, individual fiber optic cables can be spaced at least 1 mm apart to allow a certain degree of freedom of movement. This allows for cushioning of movements caused by vibrations without the fiber optic cables rubbing against each other and damaging their surfaces. It can also compensate for inaccuracies due to manufacturing tolerances.

[0018] In an analogous manner, it can be provided that the light coupling section of the light guide is spaced at least 1 mm from the light coupling section of the radiating element.

[0019] In a further aspect, the invention relates to a motor vehicle and a motor vehicle headlight with a lighting system according to the invention.

[0020] The invention is explained in more detail below with reference to several exemplary and non-limiting embodiments, which are illustrated in the figures. Fig. 1 a schematic representation of a lighting system according to the state of the art, Fig. 2 a schematic representation of an embodiment of a lighting system according to the invention, Fig. 3 a perspective view of the light guides and the radiating element according to Fig. 2 , Fig. 4 a detailed representation of individual components of the lighting system according to Fig. 3 , Fig. 5 a further perspective view of a section of individual components of the lighting system according to Fig. 4 , Fig. 6 in a detailed representation of the Fig. 5 an exemplary course of a light beam a coupled through the light guide 11b into the radiating element 10 and emitted by this and Fig. 6a a simplified representation of the transition of the light beam a from the light guide 11b into the radiating element 10.

[0021] In the following, unless otherwise stated, the same reference symbols refer to the same features.

[0022] Figur 1 shows a schematic representation of a lighting system 1 according to the prior art. Therein, a control unit 5 can be seen, which is connected to the light sources 22a to 22d. The light sources 22a to 22d couple light into downstream light guides 21a to 21d, which in turn emit / decouple light forward in the direction V shown by arrows. Due to the structural design of the lighting system according to the prior art, in particular due to the spacing of the light guides 21a to 21d from one another, dark areas V0 arise between light images VA to VD, which are assigned to the respective light guides 21a to 21d. These dark areas V0 lie between the brightly illuminated areas VA to VD and impair the quality of a running light effect controlled by the control unit 5 or do not provide a continuous, homogeneous light image.

[0023] Figur 2 shows a schematic representation of an exemplary embodiment of a lighting system 2 according to the invention. In this, a control unit 5 can be seen, which is connected to light sources 12a to 12d, which are followed by light guides 11a to 11d, so that the light sources 12a to 12d couple light into the light guides 11a to 11d. The light guides 11a to 11d are designed as light rods, which in the embodiment shown have two straight legs 11d' and 11d‴ and a curved section 11d" connecting the straight legs (for easier representation of the Fig. 2 only the light guide 11d was provided with the corresponding reference numerals; the remaining light guides 11a to 11c are shaped analogously). Alternatively, the light guides 11a to 11d or light rods could also have any other shape. The light guides 11a to 11d are preferably designed as solid bodies, which can be made of transparent polycarbonate, for example. The legs 11d' and 11d‴ are at an angle of at least 60° to each other. The light source 12d feeds light into the straight leg 11d', which is guided via the curved section 11d" into the adjoining straight leg 11d‴, where it reaches a light output section 14d (analogous to 14a to 14c), which is shown in Figure 3, and is introduced into a downstream light-transmitting radiating element 10.For this purpose, the radiating element 10 has light coupling surfaces 18a to 18d, which, together with inclined step surfaces 17a to 17c, form a step-shaped light coupling section 19 of the radiating element 10. The legs 11d‴ (and analogously corresponding legs of the light guides 11a to 11c) are received in the steps or rest against corresponding surfaces of the steps. The radiating element 10 is configured to emit light in the emission direction V, with the light exiting through the light exit surface 25 of the radiating element 10, so that no dark area lies between the light images generated by the individual light sources 12a to 12d. A running light effect can be achieved, for example, by sequentially switching on the light sources 12d to 12a. Any transitions of the luminous intensity of the light emitted by the light sources 12a to 12d can also be specified.Of course, it is possible to vary the number of light sources and light guides as desired, but at least two light sources and light guides must be provided. Preferably, the light sources are activated in a temporal sequence that allows a running light effect to be achieved, directed from the interior of the vehicle to the exterior of the vehicle. In the present arrangement, this corresponds to a sequence in which light source 12d is activated first, followed by 12c, 12b, and finally 12a.

[0024] A light image created in this way is particularly uniform and has no undesirable dark areas. The direction of the running light is Fig. 2 by an arrow labeled with the letter L. In order to comply with legal requirements for use on a vehicle, the running direction L of the running light generated by the lighting system 2 can be provided to run from the center of the vehicle to an exterior area of ​​the vehicle, for example, from a vehicle radiator / grille to the fender of a vehicle. In the embodiment illustrated according to the invention, the radiating element 10 is constructed in one piece and has a continuous light exit surface 25.

[0025] The diameter d of the light sticks (see Fig. 2 ) is less than the height h of the corresponding step (see Fig. 4 ), which is preferably at least 1 mm larger than the diameter d. Typical diameters of the light guides 11a to 11d or of the light rods are between 6 mm and 10 mm. The individual light guides 11a to 11d preferably run essentially parallel to one another, at least in sections, as a result of which the light sources 12a to 12d assigned to the light guides 11a to 11d can be arranged close to one another and mounted on a common heat sink. This enables a more compact design. Aperture elements (not shown in the figures) can be arranged between the light guides 11a to 11d; these are opaque and can therefore prevent undesired coupling between the light guides 11a to 11d. Preferably, the light coupling sections 14a to 14d of the light guides 11a to 11d are spaced apart by a distance s of at least 1 mm from a corresponding light coupling section 18a to 18d of the radiating element 10.In other words, the light guides 11a to 11d have regions (light-coupling sections 14a to 14d) from which light is deflected forward into the radiating element 10 by deflecting prisms (the imperfections 13). Furthermore, the light guides 11a to 11d have regions with a preferably smooth sheath to guide the light to the light-coupling sections 14a to 14d in order to transmit light with as little loss as possible.

[0026] Figur 3 shows a perspective view of a section of the lighting system 2 according to the Fig. 2 , in which only three light guides 11a to 11c are shown. Light entry surfaces 20a to 20c of the light guides 11a to 11c are shown, into which the Figur 3 Light sources 12a to 12c, not shown, couple in light. These light entry surfaces are shown only schematically and as examples and can, of course, be designed differently and are adapted to the radiation characteristics of the light sources used in order to ensure efficient use of the emitted luminous flux. The light guides 11a to 11c each have a light output section 14a to 14c, wherein optical defects or defect elements 13a to 13c are provided therein, which are designed, for example, as prism-like projections or depressions. The defects orImpurity elements 13a to 13c (each light guide preferably has at least one light extraction section with impurities) are configured to couple light into corresponding light coupling surfaces 18a to 18c of the emitting element 10, wherein the sum of the light extraction surfaces forms a light extraction section 19 of the emitting element 10. It is essential for the invention that each light guide has a region for efficiently transmitting the light that is free of impurities (e.g., through a smooth outer contour; as in optical fibers) – corresponding to the "light guide section" 15. In addition, each light guide has a region for coupling out light, namely a "light extraction section" 14, wherein the light extraction takes place with the aid of impurities arranged within the light extraction section 14, e.g., prism surfaces 13.

[0027] The optical fiber decoupling sections 14a,b,c,d are assigned to the radiating element irradiation areas 18a,b,c,d.

[0028] Fig. 4 shows a detailed representation of individual components of the lighting system 2 according to the Figur 3 . This shows the height h of a step of the radiating element 10, which is formed by the step surface 17b (or 17a). The step surfaces 17a or 17b (as well as the other Fig. 4 not shown step surfaces) are formed by corresponding edges 36b, 37a, the edge opposite the edge 37a (in Fig. 4 not visible) and by the edge 38a or 36c, 37b and 38b, etc. The edges 36b, 39b (as well as an edge running parallel to the edge 39b not shown in this figure) and 38b delimit the light coupling surface 18b (this applies analogously to other light coupling surfaces).

[0029] Figur 5 shows a further perspective view of a section of individual components of the lighting system 2. It can be seen that the step surface 17a or the edge 37a is oriented parallel to a vehicle axis, with the vehicle axis pointing in the direction of travel when a vehicle is traveling straight ahead. This makes it possible to keep the areas between the light-coupling sections 14a to 14c as small as possible and thereby achieve homogeneous light emission. The light images VA and VB generated by the emission element 10 or the associated light guides 11a and 11b overlap, so that no dark areas occur between the light images VA and VB.

[0030] Fig. 6 shows in detail the Fig. 5 an exemplary course of a light beam a coupled through the light guide 11b into the radiating element 10 and emitted by it. The light beam a is applied to a Fig. 6a The light beam a is reflected from the defect 13b (illustrated in more detail, a prism surface) at the closest point in the direction of light propagation (i.e., at a first coupling-out defect), whereby the light beam a is refracted at the transition from the light guide 11b into the radiating element 10 (as well as at each subsequent transition between media with different refractive indices). As a result, the light beam a is offset laterally, whereby the offset depends on the refractive indices of the materials of the light guide and the radiating element, the surrounding medium (air), and the size of the distance s.The position and configuration of the defect 13b1 reflects the light beam a such that, after exiting the light guide 11b, it is offset relative to the vehicle axis and oriented parallel to it, so that an area imaged in front of the radiating element 10 and located between the output sections 14a and 14b is also supplied with light beams and illuminated. Reference symbol n denotes a normal axis to a prism surface of a defect.

[0031] Fig. 6a shows a simplified representation of the transition of the light beam a from the light guide 11b into the radiating element 10, in which the light refraction in the transition between the light guide 11b and the radiating element 10 has been neglected. A lateral displacement δL corresponds to the normal distance of the edge 38a or the step surface 17a to a first defect 13b1 of the light guide 11b, so that the light beam a emerging from the light guide 11b is deflected past the edge 38 and radiates into the boundary region of the light images LA and LB.

[0032] A recommended minimum value for the lateral displacement δL is calculated from the following in Fig. 6a parameters shown: δLLateral displacement in the (horizontal) normal direction to the vehicle axis δL*Lateral displacement along the light guide hHeight of the step dDiameter of the light guide sWidth of the air gap between the light guide and the step body αTilt (at the respective step) of a light guide carrier curve to the vehicle transverse direction nRefractive index of the materials (n1 for light guide, n2 for radiating element) δL=δL1+δL2=δL1*+δL2*·cosα=cosα·D∗·sinα−β1 / sinγ+h·sinφ / sin90°+β2=cosα·D∗·sinα−β1 / cosβ1+h·sinα−β2 / cosβ2 with sinα=n1sinβ1&sinα=n2sinβ2 and D* = d / cos αFor n1=n2= n (thus β 1 = β 2 = β) the expression for the lateral displacement of the first impurity element13b1 is simplified δL=cosα·sinα−β / cosβD∗+h

[0033] This results in a minimum value for the lateral displacement δL according to δL ∗ = δ L / cos α .

[0034] All of the above-mentioned embodiments of the invention can be produced cost-effectively and efficiently and enable a compact arrangement of the light sources, which can be arranged, for example, on a common heat sink and / or a common circuit board.

[0035] In light of this teaching, the invention may be modified in any manner known to those skilled in the art and is therefore not limited to the embodiments shown. Individual aspects of the invention may also be taken up and combined with one another. What is essential are the ideas underlying the invention, which can be implemented in a variety of ways by a person skilled in the art with knowledge of this description and yet remain as such. The invention is limited only by the appended claims.

Claims

1. Motor vehicle having a motor vehicle headlamp with a light system (2), comprising at least two light sources (12a to 12d), at least two light guides (11a to 11d), at least one downstream light-transmitting radiating element (10) and at least one control unit (5) for time-delayed actuation of the at least two light sources (12a to 12d), wherein the at least two light sources (12a to 12d) are arranged to couple light into a respective light guide (11a to 11d), wherein the light guides (11a to 11d) each have at least one light decoupling section (14a to 14c) which is arranged to couple light into a light coupling section (19) of the radiating element (10), wherein the light guides (11a to 11d) are each a structure in which incident light can be reflected along the extension of the light guide by total reflection at the walls, wherein the light guides (11a to 11d) are designed as light rods (11a to 11d), wherein the light rods have optically effective interference points (13a to 13c) which are arranged to deflect light propagating along the light rod (11a to 11d) in such a way that it emerges from the light rod (11a to 11d) through the light decoupling section (14a to 14c) and enters the light coupling section (19) of the radiating element (10), characterized in that the radiating element (10) has light coupling surfaces (18a to 18d) which, together with inclined step surfaces (17a to 17c), form the light coupling section (19) of the radiating element (10) in a stepped manner, wherein a light rod (11a to 11d) is associated with each step and the inclined step surfaces (17a to 17c) are oriented parallel to a vehicle axis, wherein the vehicle axis points in the direction of travel when a vehicle is traveling in a straight line, wherein a light decoupling section (14a to 14c) is associated with each light coupling surface (18a to 18d), wherein the interference points (13a to 13c) are arranged to couple light into corresponding light coupling surfaces (18a to 18d) of the radiating element (10), wherein the radiating element (10) is designed in one piece and has a continuous light emission surface (25).

2. Motor vehicle according to claim 1, characterized in that the light guides (11a to 11d) have two straight legs (11d', 11d‴) which are connected to one another by means of a curved section (11d"), the straight legs (11d', 11d‴) forming an angle of at least 60° to one another.

3. Motor vehicle according to claim 1 or 2, characterized in that the number of light guides (11a to 11d) exceeds the number of steps by the value one.

4. Motor vehicle according to one of claims 1 to 3, characterized in that at least three light guides (11a to 11d) are provided.

5. Motor vehicle according to one of claims 1 to 4, characterized in that the height (h) of each step is greater than the diameter (d) of a corresponding light guide (11a to 11d).

6. Motor vehicle according to one of claims 1 to 5, characterized in that individual light guides (11a to 11d) run essentially parallel to one another, at least in sections.

7. Motor vehicle according to one of claims 1 to 6, characterized in that diaphragm elements are arranged between the light guides (11a to 11d).

8. Motor vehicle according to one of claims 1 to 7, characterized in that individual light guides (11a to 11d) are spaced at least 1 mm apart.

9. Motor vehicle according to one of claims 1 to 8, characterized in that the light decoupling section (14a to 14c) of the light guide (11a to 11d) is spaced at least 1 mm from the light coupling section (19) of the radiating element (10).

10. Motor vehicle according to one of claims 1 to 9, wherein the light guides (11a to 11d) are designed as solid bodies.