Lighting device for vehicles

Abstract

Lighting device for vehicles with a housing (1) in which a first light unit (2) and at least one second light unit (4) arranged behind it in the main emission direction (3) are arranged, wherein the first light unit (2) has a planar first light guide element (5, 18) with a rear side (10) facing the second light unit (4), with a front side (11) facing away from the second light unit (4) and with a narrow side connecting the rear side (10) to the front side (11), to which at least one luminaire element is assigned as a light coupling surface for coupling the light into the planar first light guide element (5, 18), and wherein the rear side (10) and / or the front side (11) of the planar first light guide element (5, 18) is provided with a number of coupling elements, so that a light beam (L1) of a predetermined luminous intensity distribution can be emitted from the front side (11) of the planar first light guide element (5, 18),wherein the at least second light unit (4) has a planar second light guide element (12, 18') with coupling elements arranged on a front (13) and / or on a rear (14) thereof, characterized in that the planar first light guide element (5, 18) of the first light unit (2) is arranged at a predetermined distance to the planar second light guide element (12, 18') of the second light unit (4) and that the coupling elements of the first light unit (2) and the at least second light unit (4) are spatially coordinated, wherein an area density of the coupling elements assigned to the second light unit (4) is at least partially greater than an area density of the coupling elements assigned to the first light unit (2), such that a denser zone of coupling elements is present on an area of ​​a surface in the main emission direction (3) behind the planar first light guide element (5, 18)18) of the first light unit (2) arranged in a planar second light guide element (12, 18') of the second light unit (4), such that an aperture (24) is arranged between the first light guide element (5, 18) and the second light guide element (12, 18') to generate a predetermined illumination pattern, wherein the aperture (24) is provided with a number of linear recesses (25) and a rectangular recess (26).

Description

The invention relates to a lighting device for vehicles according to the preamble of claim 1. From DE 102 07 694 A1, a lighting device for vehicles is known, comprising a first lighting unit consisting of a planar light guide element and a light source, and a second lighting unit consisting of a reflector and a light source. The planar light guide element is arranged in front of the second lighting unit in the main emission direction and completely covers it. A series of LEDs is arranged as light sources on one narrow side of the planar light guide element, such that the light emitted by them is coupled in at the narrow side of the planar light guide element and then totally internally reflected at a planar front surface and at a rear surface opposite it. Coupling elements are arranged on the planar rear surface of the planar light guide element, so that the injected light is deflected towards the front surface of the light guide element and coupled out there.The lighting element associated with the reflector is designed as an incandescent lamp that can be switched on and off independently of the LEDs associated with the light guide element. The first and second lighting units can be operated simultaneously to create a combined lighting function. Because the area and / or the number of output elements increases continuously from the narrow side of the planar light guide element, which serves as the light input surface, a homogeneous light emission can be achieved across the surface of the planar light guide element, acting as a "light curtain." This homogeneous light emission can be used, for example, to generate a taillight function. From DE 10 2005 021 079 A1, a lighting device with a single light unit for generating, for example, a flashing light function is known, which has two elongated light guide elements. The light is coupled into the elongated light guide elements in a parallel manner, so that it is deflected by 90° towards the front in certain areas by means of reflective facets 30. A free area is arranged between the reflective facets of a light guide element in which no deflection of the coupled light occurs. In this way, light graphics can be generated that have illuminated and non-illuminated zones on the light emission side. From DE 10 2009 005 351 A1, a lighting device for vehicles is known, comprising two lighting units arranged one behind the other in the main emission direction. Each lighting unit has a planar light guide element and associated light sources. A light guide element located rearward in the main emission direction has coupling elements arranged offset from each other in its direction of extension relative to the front light guide element, so that the light coupled out at the rear light guide element is emitted parallel to and offset from the light coupled out at the front light guide element. This ensures homogeneous light emission. US Patent 2006 / 0044825 A1 discloses a lighting device for vehicles with a housing in which two planar light units are arranged one behind the other in the main emission direction. Each of the two light units has a planar light guide element with coupling elements on its rear side, allowing different lighting functions to be generated in a space-saving manner. The coupling elements of the light guide elements each have the same area density. The object of the present invention is to further develop a lighting device for vehicles in such a way that the stylistic appearance is extended in a space-saving manner without diminishing the lighting requirements with regard to the lighting function. To solve this problem, the invention has the features of claim 1. According to the invention, a lighting device has at least two planar light guiding elements, which serve firstly to generate at least one lighting function and secondly to meet higher design requirements. For example, by coordinating the arrangement of coupling elements of a first planar light guide element and a second planar light guide element, a three-dimensional appearance of the lighting device, i.e., an appearance with depth effect, can be created, wherein the at least two planar light guide elements are arranged in a space-saving manner in a housing of the lighting device. According to the invention, the coupling elements of the first light unit and the at least second light unit are spatially coordinated, so that, in particular, an optical depth effect is achieved in the operating state and / or in the non-operating state of the lighting device. The viewer is given the impression that the lighting device has a relatively large depth, at least a depth that is greater than the distance between the planar light-guiding elements of the first and at least second light units arranged one behind the other in the main emission direction. According to the invention, the area density of the coupling elements associated with the second light unit is at least partially greater than the area density of the coupling elements associated with the first light unit. The depth effect can be further enhanced by denser zones of coupling elements on a surface of a second light guide element located further back in the main emission direction. Furthermore, the coordinated arrangement of the coupling elements of the surface light guide elements relative to each other allows for additional design possibilities with regard to the luminous flux emitted from the surface of the lighting device. According to the invention, an aperture is arranged between at least two planar light guiding elements, so that a predetermined illumination pattern can be generated. According to a further development of the invention, at least two planar light-guiding elements are arranged spaced apart from each other in the main emission direction, wherein at least two light-guiding elements are arranged parallel to each other or at an angle to each other. With an angled arrangement of at least two light-guiding elements, the depth effect can preferably be further enhanced in conjunction with the distribution of coupling elements over the surface of the first or the second light-guiding element. According to a further development of the invention, the planar light guide elements can be assigned luminous elements emitting light of the same color, so that, for example, a taillight function can be generated. Alternatively, two light functions can also be generated, for example, a taillight and brakelight function, wherein the luminous elements of one light guide element are activated during the brakelight function. According to a further development of the invention, the planar light guide elements are assigned luminaires emitting different colored light. In a first embodiment, the first planar light guide element is assigned luminaires of a first color to generate a first lighting function, for example, a taillight function. The second planar light guide element is assigned luminaires of a second color, for example, yellow, to generate a flashing light function. According to a second embodiment, the first planar light guide element can also be assigned multicolored luminaires, for example, red-yellow luminaires, so that in one switching state of the luminaires, the yellow color is provided to generate the flashing light function, and in the second switching state, the red color is provided to generate, for example, the taillight function, to which the luminaires of the second planar light guide element also contribute.This allows for the creation of a variety of lighting functions in a space-saving manner. According to a further development of the invention, coupling elements are arranged on at least one planar light guide element such that a partial light beam can be coupled out at a second narrow side of the light guide element opposite the light coupling surface to generate a further light function. This partial light beam can serve, for example, to generate a side marker light function. Exemplary embodiments of the invention are explained in more detail below with reference to the drawings. Figure 1 shows a vertical section through a lighting device with a first planar light guide element and a second planar light guide element arranged parallel behind it in the main emission direction; Figure 2 shows a schematic front view of the lighting device according to a second embodiment, wherein a partial light beam is coupled out at a narrow side of the planar light guide elements; Figure 3 shows a perspective front view of the lighting device according to a third embodiment, wherein a front first light guide element has an arc-shaped extension; Figure 4 shows a perspective front view of the lighting device according to a fourth embodiment, wherein the first planar light guide element and the second planar light guide element are arranged at an angle to each other.Fig. 5 a perspective front view of the lighting device according to a fifth embodiment, wherein a shutter is arranged between two planar light guide elements, Fig. 6 a perspective front view of the lighting device according to a sixth embodiment, wherein a number of planar light guide elements are arranged in a stepped manner and converging towards a front light guide element, and Fig. 7 a perspective front view of the lighting device according to a seventh embodiment, wherein a number of planar light guide elements are arranged in a stepped manner towards a rear planar light guide element. A lighting device for vehicles is preferably arranged in a rear area of ​​the same and serves to generate one or more signal functions. Fig. 1 shows a pot-shaped housing 1 of the lighting device in which a first light unit 2 and a second light unit 4 arranged behind it in the main direction of emission 3 are provided. The first light unit 2 essentially consists of a first planar light guide element 5, which is arranged at a predetermined distance from a housing base surface 6 and substantially covers it. A series of light-emitting elements 8 are arranged on an upper narrow side 7 of the light guide element 5 for coupling the light onto the upper narrow side 7 of the front light guide element 5. The upper narrow side 7 thus serves as the light coupling surface for the front light guide element 5. The light-emitting elements 8 are preferably designed as light-emitting diodes (LEDs) or LED chips, which are arranged on a printed circuit board 9. In Fig. 1, an exemplary light beam L1 is shown, which is coupled into the front light guide element 5 at the upper narrow side 7 and is totally reflected at a rear side 10 of the front light guide element 5 in the main emission direction 3 and at a front side 11 of the front light guide element 5 in the main emission direction 3, until it hits an output coupling element not shown at the rear 10, by means of which it is reflected in the main emission direction 3, so that it exits at the front 11 towards the front in the main emission direction 3. The second light unit 4 is arranged parallel to and offset from the first light unit 2 and has a similar structure. The second light unit 4 essentially comprises a second planar light guide element 12, which—like the first light guide element—has a front 13, a back 14, and an upper narrow side 15 for coupling in the light emitted by the row-arranged light elements 16. By way of example, Fig. 1 shows a second light beam L2, which is coupled in at the upper narrow side 15 of the second light guide element 12, totally reflected at the front 13 and the back 14 until it strikes an output coupling element that reflects the light beam L2 in the main emission direction, so that it is emitted from the lighting device after refraction at the front 13, the back 10, and the front 11 of the first light guide element 5. The first light guide element 5 and the second light guide element 12 each preferably have coupling elements (not shown) on their rear sides 10 and 14, respectively, which can be designed as spherical and / or torus and / or conical and / or prismatic surfaces. Alternatively, the coupling elements can also be produced by printing or formed as an EDM or etched structure. The two light-guiding elements 5 and 12 are embedded at their edges in recesses of an edge baffle 17, which are detachably connected to the housing 1. The first planar light-guiding element 5 and the second planar light-guiding element 12 each form a "light curtain" that enables planar light emission from the respective front surfaces 11 and 13. The light-guiding elements 5 and 12 are preferably crystal clear and transparent. Alternatively, they can also be colored, for example, red, pink, yellow, green, or blue. A colored overmolding, either completely or partially, can also be provided to create the corresponding lighting effects. According to a first embodiment of the lighting device, the LEDs 8, 16 assigned to the first light guide element 5 and the second light guide element 12 are designed as luminous elements emitting light of the same color, each emitting red light to generate a taillight function. Preferably, the two rows of LEDs 8, 16 are switched on and off simultaneously, so that a beam of red light is emitted from the two light guide elements 5, 12 in the main emission direction 3. For example, the area density of the output elements assigned to the second planar light guide element 12 can be equal to or greater than the area density of the output elements assigned to the first light guide element 5, so that the depth effect caused by the light guide elements 5 and 12 being arranged at a predetermined distance from each other is further increased for the viewer. For example, the output elements can be designed as a vertically extending line structure, with the lines of the first light guide element 5 and the second light guide element 12 being aligned with each other in a vertical plane in which the main emission direction 3 extends. According to an alternative embodiment, the area density of the coupling elements, in particular of the rear light guide element 12, can be partially larger than in adjacent sections of the same light guide element 12 or than in sections of the first light guide element 5. The coupling elements of the first light guide element 5 and the second light guide element 12 are thus spatially aligned so that a predetermined depth effect can be created for the viewer. This occurs in the operating state and / or in the non-operating state of the lighting device. According to an alternative embodiment of the invention, the planar light-guiding elements 5, 12 can also be assigned LEDs 8, 16 emitting different colored light: For example, the LEDs 16 of the second light unit 4 can emit red signal light, while the LEDs 8 of the first light unit 2 emit yellow light. The first light unit 2 can therefore be used to generate a flashing light function, and the second light unit 4 to generate a taillight function. According to an alternative embodiment of the invention, the illuminating elements 8 of the first light unit 2 can preferably also be multicolored, so that to generate a flashing light function the light guide element 5 is illuminated with yellow LEDs and to generate the tail light function red LEDs 5 are switched on, which together with the red LEDs 16 of the second light unit 4 serve to form the tail light function. Identical components and component functions of the embodiments according to the invention are provided with the same reference numerals. According to a further embodiment of the invention as shown in Fig. 2, the lighting device comprises a first light guide element 18 and a second light guide element 18' arranged parallel to and offset from the rear. In accordance with the embodiment shown in Fig. 1, the circuit board 9 with the light elements 8, 16 is associated with these elements. Furthermore, a further circuit board 19 with light elements is associated with the front first light guide element 18, so that light can be coupled in at a further first narrow side 20 of the first light guide element 18. Firstly, light is coupled out at the front 11 of the first light guide element 18 to generate the first light function, see Lv in Fig. 2. Secondly, a partial light beam LT is coupled out at a narrow side 21 opposite the first narrow side 20, which serves to generate a further light function, preferably a side marker light function.The second narrow side 21 is preferably an outer edge of the light guide element 18 on the vehicle side, which has an arc-shaped contour in the vertical direction. According to a further embodiment of the invention as shown in Fig. 3, in contrast to the embodiment shown in Fig. 2, a front-mounted light guide element 22 can be provided, which has an arc-shaped extension 23 on the outside of the vehicle. This allows the light coupled in from the inside to be coupled out laterally in a planar manner, see light beam Ls. In addition, a linear partial light beam LTan can be emitted rearward, essentially opposite to the main emission direction 3 or at an angle to it, from the narrow end 21 of the arc-shaped extension 23. According to a further embodiment of the invention as shown in Fig. 4, the light guiding elements 18, 18' according to the embodiment shown in Fig. 2 can also be arranged at an angle to each other. At least one of the light guiding elements 18, 18' then forms an acute angle with the transverse axis of the vehicle. According to a further embodiment of the invention as shown in Fig. 5, an aperture 24 can also be arranged between the first light-guiding element 18 and the second light-guiding element 18', the aperture being provided with a number of linear recesses 25 and a rectangular recess 26. This allows a predetermined illumination pattern to be generated, whereby the light effect of the rear light-guiding element 18' can contribute more strongly to the total luminous flux in the area of ​​the recesses 25, 26 than in the other areas covered by the aperture 24. According to an alternative embodiment (not shown), a colored and / or transparent decorative light disc with a predetermined contour can also be arranged between the first light guide element 18 and the second light guide element 18' and / or the second light guide element 18' and the housing base surface 6. This allows the appearance of the lighting device to be further influenced, particularly when it is not in operation. According to a further embodiment of the invention as shown in Fig. 6, a plurality of elongated planar light-guiding elements 27 are arranged transversely to the main emission direction 3 in a stepped arrangement relative to one another, wherein adjacent light-guiding elements 27 partially overlap in the main emission direction 3. A front light-guiding element 27' partially overlaps two light-guiding elements 27 extending in a rear plane. According to an alternative embodiment, the light guide elements 27 can also be wider, so that complete coverage of the at least one rear light guide element 27 is made possible. According to a further embodiment of the invention according to Fig. 7, the light guiding elements 27 can also be arranged in a stepped manner transverse to the main emission direction 3 - in the opposite direction to the embodiment according to Fig. 6 - wherein the light guiding elements 27 run from the side inwards against the main emission direction 3 to a rear light guiding element 27". According to an embodiment not shown, the coupling elements can also be arranged in such a way that a partial beam of light is emitted to the rear of the light guide elements 4, 5 and thus the housing 1 is also illuminated. To generate higher light intensities for a brake light function, 5 additional coupling elements can be arranged on the first light guide element, which focus the light more strongly. Preferably, the light guiding elements 5, 12 are supplied with light from the similarly oriented narrow side 15, so that the LEDs 8, 16 can be arranged on the common circuit board 9. Reference symbol list 1 Housing 2 First light unit 3 Main beam direction 4 Second light unit 5 Light guide element 6 Housing base 7 Upper narrow side 8 Light element 9 Circuit board 10 Rear 11 Front 12 Light guide element 13 Front 14 Rear 15 Narrow side 16 Light elements 17 Edge aperture 18, 18' Light guide element 19 Circuit board 20 Narrow side 21 Output coupling narrow side 22 Light guide element 23 Arc-shaped extension 24 Aperture 25 Linear recess 26 Rectangular recess 27, 27', 27" Light guide element LS Light beam LT Partial light beam

Claims

Lighting device for vehicles with a housing (1) in which a first light unit (2) and at least one second light unit (4) arranged behind it in the main emission direction (3) are arranged, wherein the first light unit (2) has a planar first light guide element (5, 18) with a rear side (10) facing the second light unit (4), with a front side (11) facing away from the second light unit (4) and with a narrow side connecting the rear side (10) to the front side (11), to which at least one luminaire element is assigned as a light coupling surface for coupling the light into the planar first light guide element (5, 18), and wherein the rear side (10) and / or the front side (11) of the planar first light guide element (5, 18) is provided with a number of coupling elements, so that a light beam (L1) of a predetermined luminous intensity distribution can be emitted from the front side (11) of the planar first light guide element (5, 18),wherein the at least second light unit (4) has a planar second light guide element (12, 18') with coupling elements arranged on a front (13) and / or on a rear (14) thereof, characterized in that the planar first light guide element (5, 18) of the first light unit (2) is arranged at a predetermined distance to the planar second light guide element (12, 18') of the second light unit (4) and that the coupling elements of the first light unit (2) and the at least second light unit (4) are spatially coordinated, wherein an area density of the coupling elements assigned to the second light unit (4) is at least partially greater than an area density of the coupling elements assigned to the first light unit (2), such that a denser zone of coupling elements is present on an area of ​​a surface in the main emission direction (3) behind the planar first light guide element (5, 18)18) of the first light unit (2) arranged in a planar second light guide element (12, 18') of the second light unit (4), such that an aperture (24) is arranged between the first light guide element (5, 18) and the second light guide element (12, 18') to generate a predetermined illumination pattern, wherein the aperture (24) is provided with a number of linear recesses (25) and a rectangular recess (26). Lighting device according to claim 1, characterized in that the planar light guiding elements (5, 12, 18, 18', 22) are arranged spaced apart from each other in the main emission direction (3), wherein at least two light guiding elements (5, 12) are arranged parallel offset or at an angle to each other. Lighting device according to one of claims 1 to 2, characterized in that the planar light guiding elements (5, 12, 18, 18') are assigned light emitting elements of the same color (8, 16) to generate a single light function or to generate two light functions. Lighting device according to one of claims 1 to 3, characterized in that the planar light guiding elements (5, 18, 18') are assigned luminaire elements (8, 16) emitting light of different colors, wherein the first planar light guiding element (5, 18, 18') is assigned at least one luminaire element (8) of a first light color for generating a first light function and the second light guiding element (12, 18') is assigned at least one luminaire element (16) of a second light color for generating a second light function, or wherein, on the one hand, the first planar light guiding element (5, 18) is assigned at least one luminaire element (8) of a first light color for generating a first light function, and on the other hand, the first planar light guiding element (5, 18) is assigned at least one luminaire element (16) of the second light color and the second planar light guiding element (12, 18') is assigned at least one luminaire element of the second light color for generating the second light function. Lighting device according to one of claims 1 to 4, characterized in that the coupling elements of the first planar light guide element (5, 18) and / or the second planar light guide element (12, 18') are designed such that a partial light beam (LT) can be coupled out at a second narrow side (21) to generate a further light function. Lighting device according to one of claims 1 to 5, characterized in that a decorative light disc with a contour is arranged between the first light guide element (18) and the second light guide element (18') and / or between the second light guide element (18') and a housing base surface (6) of the housing (1).

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