Lighting device for vehicles

Abstract

Lighting device for vehicles with a light source (2) and with a light guide element (3) associated with the same, which - a light coupling surface (7) for coupling in light (8) generated by the light source (2), - a light extraction surface (9) for extracting the light (8, 8.1, 8.2) from the light guiding element (3), - a number of sides (10, 11, 12, 24) connecting the light coupling surface (7) with the light coupling surface (9), wherein the light coupling surface (9) has scattering optics elements (20) for scattering the coupled-out light (8, 8.1, 8.2) and wherein the light guide element (3) has an inner recess (5) with an interface (14, 15, 16, 23) at which the light coupled into the light guide element (3) (8.1) is refracted, in that the inner recess (5) has a concave or straight rear boundary surface (14) in the light-guiding direction (F) and a front boundary surface (15, 23) tapering to a point in the same direction in the light-guiding direction (F) of the light-guiding element (3), characterized in that the rear boundary surface (14) and the front boundary surface (15, 23) are connected to each other via an intermediate boundary surface (16) opening in the light-guiding direction (F), that the inner recess (5) is arranged in a front region (6) of the light-guiding element (3), that the inner recess (5) is designed such that the coupled light (8.1) striking the interface surfaces (14, 15, 16, 23) of the inner recess (5) is refracted by an angle of refraction (α) from a central plane (M) of the inner recess (5) away and / or by increasing an opening angle (φ) of the coupled light (8.1) and / or in the direction of extension (E) of the light coupling surface (9) of the light guiding element (3) away from an optical axis (A) of the light source (2) associated with the inner recess (5).

Description

[0001] The invention relates to a lighting device for vehicles according to the preamble of claim 1.

[0002] From EP 1 519 107 A1, a lighting device for vehicles is known, comprising a light source and a flat light guide element, wherein the light guide element has an inner recess in a central region. The inner recess is designed as an air lens and has interfaces at which the light coupled into the light guide element is refracted towards the optical axis of the light source. For this purpose, the air lens has convex interfaces.

[0003] From EP 2 818 791 A1, a lighting device for vehicles is known, comprising a light source and a light guide element. The light guide element has a light coupling surface on one side facing the light source and a light output surface on the other side facing away from the light source. The light coupling and light output surfaces are connected to each other via flat surfaces. A deflecting optic is integrated within the light guide element, by means of which the coupled light is parallelized so that it strikes the light output surface substantially perpendicularly. The deflecting optic includes an inner recess of the light guide element, which, acting as an air lens, has a concave-planar interface by means of which the coupled light is parallelized. This allows all the coupled light to be parallelized and guided homogeneously to the light output surface.The light output surface has scattering optics elements at which the parallelized light is refracted according to the specified light distribution.

[0004] From US patent 2007 / 0217226A1, a lighting device is known comprising a light source and a light guide element, wherein the light guide element has a plurality of internal recesses arranged near a light coupling surface. The internal recesses have a triangular cross-section and enable increased scattering of the coupled light away from an optical axis of the light source. This results in improved homogeneous light emission, which can serve as background light.

[0005] The object of the present invention is to further develop a lighting device for vehicles in such a way that a relatively wide light distribution can be generated in a simple manner, wherein in particular a light guiding element has an appealing appearance.

[0006] To solve this problem, the invention has the features of claim 1.

[0007] The particular advantage of the invention lies in the fact that an air lens integrated into a light guide element is used to broaden the opening angle of a light beam coupled into the light guide element, thus reducing the effort required for scattering at a light output surface. The fundamental concept of the invention is to shift the location of light scattering from the light output surface to a location within the light guide element. Advantageously, the number of scattering elements required at the light output surface can be reduced or even eliminated entirely, which improves the appearance of the light guide element for the observer.

[0008] According to the invention, the inner recess has a concave or straight rear boundary surface arranged at the rear in the direction of light transmission and a pointed front boundary surface arranged at the front in the direction of light transmission, so that, essentially by at least double refraction, the light is refracted away from a central plane of the inner recess. Thus, the light undergoes multiple refractions at the inner recess.

[0009] According to the invention, the inner recess is arranged in a front region of the light-guiding element, such that essentially only light refracted by the inner recess is emitted from a section of the light-emitting surface onto which the inner recess is projected. The coupled light not captured by the inner recess, or the coupled light guided past the inner recess (preferably in a parallel pattern), is essentially coupled out by a section of the light-emitting surface adjacent to the section of the light-emitting surface located in front of the inner recess in the direction of light transmission.

[0010] According to a further development of the invention, the inner recess is designed such that the coupled light is deflected away from a light-guiding direction perpendicular to the light-emitting surface within a deflection angle range of +10° to +40° and / or -10° to -40°. Advantageously, the deflection is so large that the effort required for scattering at the light-emitting surface can be significantly reduced or even eliminated entirely. The deflection occurs on both sides of the light-guiding direction.

[0011] According to a further development of the invention, the inner recess is designed as a through-hole extending from a first flat side of the light-guiding element to an opposite second flat side of the same. In this way, the same light deflection is achieved across the entire thickness of the light-guiding element with respect to a central plane in the inner recess that runs perpendicular to the flat sides and perpendicular to the light-emitting surface.

[0012] According to a further development of the invention, the light guiding element is designed as a flat light guiding element, wherein both the light coupling surface and the light output surface are formed as a narrow side. These two narrow sides are connected to each other by spaced-apart flat sides. The coupled light is optionally totally reflected at the flat sides. The inner recess is designed such that the coupled light striking it is preferably deflected or refracted in the direction of extension of the light guiding element or in the direction of extension of the light output surface. Advantageously, this allows a relatively wide light distribution to be provided along the direction of extension of the light guiding element or the light output surface.

[0013] According to a preferred embodiment of the invention, the light output surface comprises an output optic by means of which a partial beam of the coupled light that does not strike the inner recess is deflected according to a predetermined angular range in the direction of extension and / or transversely to the direction of extension of the light output surface. A further partial beam of the coupled light that falls on the inner recess is additionally refracted in the direction of extension of the light guide element and / or the light output surface, so that the deflection in the direction of extension of the light output surface is significantly greater compared to the other light beam, but is the same transversely to the direction of extension of the light output surface.Advantageously, this allows for the creation of a light distribution with a central horizontal area of, for example, + / - 20° relative to a zero point, caused on the one hand by the partial light beam passing by the inner recess, and on the other hand by an outer area of ​​+20° to +50° and -20° to -50° caused by the partial light beam striking the inner recess. The scattering perpendicular to the direction of the light output surface can be in the range of + / - 10°, thus enabling the simple creation of a light distribution for reversing lights. By varying the inner recess, a flashing light function or another signal light function can alternatively be created.

[0014] An embodiment of the invention is explained in more detail below with reference to the drawings.

[0015] They show: Fig. 1 a top view of a lighting device according to the invention, Fig. 2 a vertical cross-section through a light guiding element of the lighting device, Fig. 3 an enlarged partial section of the lighting device according to Fig. 1 and Fig. 4. Light distribution of the lighting device.

[0016] A lighting device for vehicles is preferably designed as a signal light, which is provided in a rear area of ​​the vehicle to generate a light distribution 1 designed as a reversing light. Alternatively, the lighting device can also serve to generate a direction indicator function or another signal light function.

[0017] The lighting device comprises a number of light sources 2, each associated with a light guide element 3. The light guide element 3 is formed in one piece and, in the present embodiment, has four identical light guide sections 4. Each light guide section 4 has an inner recess 5 located in a front region 6 of the respective light guide section 4 or of the light guide element 3. The inner recess 5 is arranged symmetrically with respect to an optical axis A of the light source 2 associated with the respective light guide section 4.

[0018] The inner recess 5 has interfaces at which light coupled into the light guide element 3 is refracted. The inner recess 5 is thus designed as an air lens.

[0019] The light-guiding element 3 has a light-input area 7 on a side facing the respective light sources 2 for coupling in light 8 generated by the light sources 2. Additionally, the light-guiding element 3 has a light-output area 9 on a front side facing away from the light sources 2 for coupling out the light 8. The light-input area 7 and the light-output area 9 are each configured as narrow sides. The light-input area 7 and the light-output area 9 are connected to each other via sides, specifically via a first flat side 10 and a second flat side 11 preferably running parallel to it, as well as via a first narrow side 12 and a second narrow side 24, which run substantially perpendicular to the first and second flat sides 10, 11 and preferably in the light-guiding direction F. The flat sides 10, 11 define a plane of extension E of the light-guiding element 3.

[0020] The light coupling surface 7 of the light guiding element 3 has a coupling optic 13 in the respective light guiding section 4, by means of which the light 8 emitted by the respective light source 2 is parallelized and / or collected, so that the coupled light 8 is distributed over an entire width b L The light guide section 4 or the light guide element 3 is distributed in a light guide direction F. Since the width b I the inner recess 5 is smaller than a width b L of the light guiding element 3, a first partial light beam 8.1 of the coupled light 8 hits the inner recess 5 and a second partial light beam 8.2 of the coupled light 8 does not hit the inner recess 5. The second partial light beam 8.2 is guided past the inner recess 5.

[0021] The inner recess 5 is arranged in a front region of the respective light guide section 4 or light guide element 3. The inner recess 5 has as its interface a concave rear boundary surface 14 arranged at the rear in the light guide direction F and a first front boundary surface 15 and a second front boundary surface 23 arranged at a distance from the rear boundary surface 14 and at the front in the light guide direction F, wherein the first front boundary surface 15 and the second front boundary surface 23 are each formed as tapered flanks. An intermediate boundary surface 16 extends between the rear boundary surface 14 on the one hand and the first front boundary surface 15 and the second front boundary surface 23 on the other hand, preferably widening slightly in the light guide direction F. The inner recess 5 is arranged symmetrically with respect to the optical axis A of the light source 2.A median plane M of the inner recess 5 runs perpendicular to the flat sides 10, 11 and in the direction of the light guiding direction F. The optical axis A and the median plane M pass through a point 17, which is formed by converging front ends of the first front interface 15 and the second front interface 23 of the inner recess 5.

[0022] As from Fig. As can be seen from Figure 1, the distance a between the first front interface 15 and the second front interface 23 or the tip 17 of the inner recess 3 to the light output surface 9 is smaller than a length I running in the light guidance direction F. A the inner recess 5 and smaller than half the extent I running between the light coupling surface 7 and the light coupling surface 9 L of the light guiding element 3 or of the light guiding section 4.

[0023] The inner recess 5 is designed as an opening extending from the first flat side 10 to the second flat side 11. In a plane running transversely to the flat sides 10, 11, the boundary surfaces 15, 16, 23 of the inner recess 5 each lie in a plane.

[0024] As especially from Fig. As can be seen in Figure 3, the light beam 8.1, refracted at the interfaces 14, 15, 16, 23 of the inner recess 5, is refracted or deflected, forming an opening angle φ of 80°. With respect to the central axis M or the optical axis A, light from the first partial light beam 8.1 is refracted away from the optical axis A or the central axis M at an angle of refraction α in a range of 0° to +40° and 0° to -40°. Alternatively, the angle of refraction α can be refracted away from the optical axis A or the central axis M in a range of 0° to +30° and 0° to -30°. The refraction of the light beam 8.1 caused by the interfaces 14, 15, 16, 23 occurs exclusively in the direction of extension E of the light coupling surface 9 or the light guiding element 3.

[0025] According to an embodiment not shown, the angle of refraction α can be refracted asymmetrically away from the optical axis A or the central axis M, for example in a range from 0° to +40° and from 0° to -30° away from the optical axis A or the central axis M.

[0026] The first partial light beam 8.1, refracted at the inner recess 5, strikes a first section 18 of the light output surface 9. The second partial light beam 8.2, which does not strike the inner recess 5, strikes a second section 19 of the light output surface 9, which preferably overlaps with the first section 18 of the light output surface 9.

[0027] The light output surface 9 comprises an output optic that extends continuously in the direction E of the light output surface 9. The output optic is formed by torus-shaped and / or convex and / or concave scattering elements 20 that cover the light output surface 9. The torus-shaped scattering elements 20 cause incident light 8 to be deflected in the direction E of the light output surface 9 and perpendicular to the direction E of the light output surface 9 by an angle β of at least + / - 10°, in particular + / - 20°.

[0028] To generate the reversing light distribution 1 according to Fig.The direction of extension E of the light guiding element 3 or the light coupling surface 9 runs horizontally. The second light beam 8.2 is scattered or deflected by the second sections 19 of the light coupling surface 9 such that an inner illuminating area 21 is created, which extends horizontally H in a range of -20° to +20° and vertically in a range of -10° to +10°. By superimposing the scattering elements 20 and the inner recess 5, the first partial light beam 8.1 is deflected from the second section 18 to outer illuminating areas 22, 22' of the light distribution 1. One of the outer illuminating areas 22 extends horizontally from +20° to +50° and vertically from -10° to +10°. The outer illumination area 22' extends horizontally from -50° to -20° and vertically from -10° to +10°. This results in a relatively wide and homogeneous light distribution 1.

[0029] According to an alternative embodiment of the invention (not shown), the scattering elements 20 can also be conical. A prismatic shape for the scattering elements 20 is not necessary, since the increase in scattering effect in the direction E of the light guide element 3 is achieved by the internal recesses 5. The scattering elements 20 can be formed, for example, by printing or as an EDM or etching structure.

[0030] According to an alternative embodiment of the invention (not shown), the number of light guide sections 4 can also be varied. If the light source 2 is particularly bright, the light guide element 3 can, for example, consist of only a single light guide section 4, i.e., the light guide element 3 is assigned only a single light source 2.

[0031] According to an alternative embodiment of the invention (not shown), the light guide element 3 can also be L-shaped, with the light being coupled in at an angle to the coupling arm extending from the rest of the light guide element 3. In this variant, an optical axis of the light source 2 runs perpendicular to, or at an angle to, the extent of the light coupling surface 9. Reference symbol list 1 Light distribution 2 light sources 3 Light guiding element 4 Light guide section 5 inner recess 6 front area 7 Light coupling area 8, 8.1, 8.2 Light / Partial light beam 9 Light extraction area 10 1. Flat side 11 2. Flat side 12 narrow pages 13 Coupling optics 14 Back-boundary surface 15 Front interface 16 Intermediate interface 17 top 18 Section 1 19 Section 2 20 scattering elements 21 Lighting area 22.22' outer lighting areas 23 Front interface 24 narrow pages A optical axis F Light guiding direction M Central axis b I Width b L Width a distance I A length I L Extension E Extension direction H Horizontal α Angle of refraction φ Opening angle β,γ angular ranges

Claims

Lighting device for vehicles with a light source (2) and with a light guide element (3) associated therewith, comprising: - a light coupling surface (7) for coupling in light (8) generated by the light source (2), - a light coupling surface (9) for coupling out the light (8, 8.1, 8.2) from the light guide element (3), - a number of sides (10, 11, 12, 24) connecting the light coupling surface (7) with the light coupling surface (9), wherein the light coupling surface (9) has scattering optic elements (20) for scattering the coupled-out light (8, 8.1, 8.2) and wherein the light guide element (3) has an inner recess (5) with an interface (14, 15, 16, 23) at which the light (8) coupled into the light guide element (3)1) is refracted, in that the inner recess (5) has a concave or straight rear boundary surface (14) in the light-guiding direction (F) and a front boundary surface (15, 23) tapering to a point in the same direction in the light-guiding direction (F) of the light-guiding element (3), characterized in that the rear boundary surface (14) and the front boundary surface (15, 23) are connected to each other via an intermediate boundary surface (16) opening in the light-guiding direction (F), that the inner recess (5) is arranged in a front region (6) of the light-guiding element (3), that the inner recess (5) is designed such that the coupled light (8.1) striking the interface surfaces (14, 15, 16, 23) of the inner recess (5) is refracted by an angle of refraction (α) from a median plane (M) of the inner recess (5) removed and / or by increasing an opening angle (φ) of the coupled light (8.1) and / or in the direction of extension (E) of the light coupling surface (9) of the light guiding element (3) away from an optical axis (A) of the light source (2) associated with the inner recess (5). Lighting device according to claim 1, characterized in that the angle of refraction (α) lies in an angular range of ±10° to ±40°. Lighting device according to claim 1 or 2, characterized in that a front end (17) of the inner recess (5) has a distance (a) to the light output surface (9) of the light guide element (3) which is smaller than a length (IA) of the inner recess (5) extending in the direction of light guidance (F) and / or is smaller than half a length (IL) of the light guide element (3) extending between the light input surface (7) and the light output surface (9). Lighting device according to one of claims 1 to 3, characterized in that the inner recess (5) is designed as a through-hole extending from a first flat side (10) of the light guide element (3) to an opposite second flat side (11) of the same light guide element (3). Lighting device according to claim 4, characterized in that the first flat side (10) and the second flat side (11) of the light guiding element (3) run parallel to each other. Lighting device according to claim 4 or 5, characterized in that the first flat side (10) and the second flat side (11) of the light guiding element (3) define a plane of extension of the light guiding element (3). Lighting device according to one of claims 4 to 6, characterized in that the light coupling surface (7) and the light coupling surface (9) are designed as a narrow side and that the light coupling surface (7) and the light coupling surface (9) are connected to each other by the first flat side (10) and the second flat side (11). Lighting device according to one of claims 1 to 7, characterized in that the inner recess (5) has a width (bi) which is smaller than a width (bL) of the light guiding element (3), so that a first partial light beam (8.1) of the coupled light (8) hits the inner recess (5) and a second partial light beam (8.2) of the coupled light (8) does not hit the inner recess (5). Lighting device according to one of claims 1 to 8, characterized in that the light coupling surface (7) has a coupling optic (13) so that the light (8) incident on the light coupling surface (7) from the light source (2) is parallelized and / or collected in the light guiding direction (F). Lighting device according to one of claims 1 to 9, characterized in that the light output surface (9) has an output optic such that the coupled light (8) is deflected in a direction of extension (E) of the light output surface (9) in an angular range of - 20° to + 20°, in particular from - 10° to + 10° and / or transversely to the direction of extension (E) of the light output surface (9) in an angular range (β) of - 10° to + 10°. Lighting device according to one of claims 1 to 10, characterized in that the output optics are arranged continuously in the extension direction (E) of the light output surface (9). Lighting device according to one of claims 1 to 11, characterized in that the output coupling optics are formed by torus-shaped and / or convex and / or concave scattering elements (20).

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