Lighting device for vehicles

Abstract

Lighting device for vehicles with a flat light guiding element (1), - which has opposite flat sides (5) on which coupled light is totally reflectable, - which in a light coupling area (3) has a first narrow side (4) for coupling in light emitted by a light source (10', 10'') arranged in the light coupling area (3), wherein coupling means assigned to the light sources (10', 10'') are provided on the first narrow side (4), - which has a second narrow side (6) in a light extraction area (7) for extraction of the light, that the first narrow side (4) of the planar light guiding element (1) is at least partially planar, that a number of light supply channels (2, 2', 2'') corresponding to the number of light sources (10', 10'') project from the first narrow side (4) of the planar light guiding element (1), at the free ends of which a light entry surface (9, 9', 9'') is provided, at which the light emitted by the light source (10', 10'') enters the light supply channel (2, 2', 2''), and at the second end of which, facing the first narrow side (4) of the planar light guiding element (1), a light transition area (12', 12'') is provided, from which the light in the respective light supply channels (2, 2', 2'') entered light is transferred to the first narrow side (4) of the planar light guiding element (1), characterized in that,that two adjacent light supply channels (2', 2'') are connected to each other in a light entry area (14) of the same, wherein the two light supply channels (2', 2'') run in a V-shape, spreading outwards from the light source side towards the first narrow side (4) of the planar light guiding element (1).

Description

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

[0002] From EP 2 354 637 A2, a lighting device for vehicles is known with a planar light guide element that can be used to generate elongated light signatures, such as daytime running lights, position lights, taillights, brake lights, and direction indicators (edge ​​light light guide). For this purpose, the planar light guide element has a first narrow side in a light-input area, into which light is coupled, and a second narrow side in a light-output area, from which the light is coupled to generate the light signature. Opposing flat surfaces extend between the first and second narrow sides, at which the coupled light is totally reflected in the direction of the second narrow side. A series of light sources (LED light sources) is arranged in the light-input area.Parabolic protrusions are formed on the first narrow side of the planar light-guiding element as coupling means. The light sources are arranged in the apex of these protrusions, so that the coupled light is essentially parallelized towards the second narrow side. The known lighting device allows the light coupled into the planar light-guiding element to be branched off into another planar light-guiding element, from which it is emitted via a flat surface. This results in the coupled luminous flux being divided into different branches.

[0003] When different lighting functions are required, such as daytime running lights and turn signals, it is already known to arrange two rows of light sources emitting different colors along the first narrow side of the planar light guide element. When the first row of light sources is switched on, white daytime running lights are coupled into the same planar light guide element, and when the second row of light sources is switched on, yellow turn signal lights are coupled into the same element. Each light source has its own coupling element on the first narrow side of the planar light guide element. For a necessarily larger coupling edge, the wall thickness of the planar light guide element must be increased, requiring the element to be manufactured using multi-stage injection molding. This results in a relatively high weight for the light guide element.The complexity of designing the light coupling area increases further if not just two, but three or more light functions of different colors are to be generated via the same flat light guide element. For example, a third light function with a different color might be desired, which is activated when the vehicle is opened or closed. This could involve using light sources emitting blue or green light, or light sources emitting a mixed color, the light from which would need to be coupled into the flat light guide element. If three rows of light sources were arranged side by side in the light coupling area, the required wall thickness of the flat light guide element for coupling the light would have to be increased even further.The requirements for the uniform illumination of the relatively narrow light output area of ​​the planar light guide element also increase.

[0004] From DE 10 2010 012 634 A1, a lighting device for vehicles is known with a planar light guide element, in the cross-section of which rectangular light supply channels are arranged at the light coupling area. Adjacent light supply channels are connected to each other, with inclined surfaces being formed between the light supply channels, which are bounded by cutouts.

[0005] From DE 10 2011 089 575 B3, a lighting device with a planar light-guiding element is known. Light supply channels, tapering conically towards a light-entry surface, are provided on one narrow side of the planar light-guiding element.

[0006] From DE 10 2013 204 021 A1, a lighting device for vehicles is known, comprising a planar light-guiding element with opposing flat sides on which coupled light is totally reflectible. On one narrow side, the planar light-guiding element has coupling elements so that the coupled light is deflected towards an opposite narrow side. On another narrow side of the planar light-guiding element, a plurality of straight light-input channels are provided. These channels taper from the planar light-guiding element towards a light-input surface of the respective light-input channels.

[0007] From DE 10 2011 088 702 A1, a lighting device for vehicles is known, comprising an elongated, tubular light guide element. A parallelization section is arranged on the light-entry narrow side of this element. A plurality of light supply channels are integrally formed on the light-entry side of the parallelization section. These channels are arranged in arcs with varying curvatures and are spaced apart from one another in a row within a light-entry area. The light supply channels converge in the direction of the parallelization section.

[0008] The object of the present invention is therefore to further develop a lighting device for vehicles with a planar light guide element, at one narrow side of which the light is coupled out, in such a way that a series of three or more light source types can be arranged in the light coupling area for coupling in different light, whereby a homogeneous linear light emission is ensured with the lowest possible increase in weight and ease of manufacture.

[0009] To solve this problem, the invention has the features of claim 1.

[0010] According to the invention, each light source is assigned a light supply channel that projects from a first narrow side, serving as the light coupling surface of a planar light guide element, towards the light source. Each light source is thus assigned a separate light supply channel, enabling optimal light coupling into the planar light guide element. The light sources are arranged at a distance from the light coupling surface of the planar light guide element. Advantageously, this allows several light sources emitting different light colors to be assigned to the same narrow side of the light guide element, ensuring uniform illumination of the linear light coupling surface of the light guide element and thus homogeneous light emission or light function. Preferably, the light sources are...The light transmission area of ​​the light supply channels is arranged uniformly in a row along the extension direction of the first narrow side of the planar light guiding element.

[0011] According to the invention, two adjacent light supply channels are connected to each other in a light entry area. This increases the stability of thin light supply channels. Furthermore, some of the light intended for one light supply channel can also be directed into the other channel, so that each of the two light sources directs light through both light supply channels into the planar light guide element, thereby ensuring better and broader illumination.

[0012] According to a preferred embodiment of the invention, the light entry surface of the light supply channel is adapted in its contour to the light emission characteristics of the light source, so that a relatively high luminous flux can enter the light supply channel.

[0013] According to a further development of the invention, the light guide channel can run in a straight line and / or an arc. Advantageously, this allows for variable positioning of the light sources at an angle to the planar light guide element or to the side of the planar light guide element. Advantageously, this allows all light sources to be positioned on a single circuit board.

[0014] According to a further development of the invention, the light-emitting first narrow side of the planar light-guiding element is divided into stepped, planar light-emitting sections, each of which projects an equal number and / or shape of light supply channels. This ensures a design of the lighting device adapted to the installation space with a constant depth of the planar light-guiding element.

[0015] According to a further development of the invention, the light supply channels run in a single row in the direction of extension of the first narrow side of the light-guiding element that couples in the light. Preferably, the light transfer areas of the light supply channels are also arranged at an equal distance from each other, so that on the one hand a space-saving arrangement of the light sources and on the other hand uniform illumination is ensured.

[0016] The vehicle uses LED light sources that provide light in the signal colors white, red, or yellow. For a so-called welcome / goodbye function, which is activated when unlocking / locking the vehicle, any other light color can also be used, such as blue, green, cyan, purple, etc. This can be achieved directly with a corresponding colored LED light source or by using an RGB LED to mix the desired color.

[0017] Further advantages of the invention will become apparent from the further dependent claims.

[0018] Exemplary embodiments of the invention are explained in more detail below with reference to the drawings.

[0019] They show: Fig. 1 a perspective top view of a lighting device with a planar light guiding element and with several light supply channels arranged in a light coupling area of ​​the light guiding element, Fig. 2 a side view of the lighting device, Fig. 3 an enlarged view of the lighting device from behind in the area of ​​two planar light coupling sections of the planar light guiding element, Fig. 4 a rear view of the in Fig. 3 shown section of the lighting device and Fig. 5 a bottom view of the lighting device in a light coupling area of ​​a planar light coupling section of the planar light guiding element.

[0020] A vehicle lighting device essentially serves to generate a linear light signature, which can be used, for example, for daytime running lights, position lights, taillights, brake lights, or turn signals. Preferably, the lighting device provides at least three different colored light signatures. In addition to the signal colors white, red, and yellow, any other color can also be used to implement a so-called welcome / goodbye function when the vehicle is opened or closed.

[0021] The lighting device essentially consists of a planar light-guiding element 1 and a plurality of light supply channels 2, which are arranged in a light coupling area 3 of the light-guiding element 1. The planar light-guiding element 1 has a first narrow side 4 in the light coupling area 3, into which light is coupled. Furthermore, the planar light-guiding element 1 has flat sides 5 adjoining the first narrow side 4, at which the coupled-in light is totally reflected and transmitted to a second narrow side 6, at which it is coupled out according to the light signature. The second narrow side 6 is located in a light coupling area 7 of the light-guiding element and serves as its light coupling side. The light signature is linear and corresponds to the path of the second narrow side 6.

[0022] For example, from Fig. As can be seen in Figure 1, the first narrow side 4 of the planar light-guiding element 1 is divided into light coupling sections 8 arranged in a stepped, offset manner. Each light coupling section 8 is planar. The light coupling sections 8 run parallel to each other. In the present embodiment, the light coupling sections 8 do not extend parallel to the light-emitting second narrow side 6, but at an acute angle to it. By orienting the light coupling section 8, the direction of light coupling into the planar light-guiding element 1 can be adjusted.

[0023] Each light coupling section 8 of the planar light guiding element 1 is assigned three light supply channels 2', 2'', 2'''. The light supply channels 2', 2'', 2''' run in an arc and at a right angle, so that a free end of the light supply channels 2', 2'', 2''', serving as a light entry surface 9, runs perpendicular to a surface of the light coupling section 8, or an optical axis of light sources 10', 10'', 10''' runs parallel to the surface of the light coupling section 8 or to the first narrow side 4 of the planar light guiding element 1. Each light entry surface 9 is assigned a light source 10', 10'', 10''', which emits light of different colors. For example, the first light source can emit 10' white light to create a daytime running light function, the second light source can emit 10'' yellow light to create a direction indicator, and the third light source can emit 10''' blue light to create a marking or warning function.The light sources 10', 10'', 10''' are preferably designed as semiconductor-based light sources, preferably light-emitting diodes.

[0024] The light supply channels 2', 2'', 2''' are cylindrical with a lateral surface 11 at which the light coupled in via the light entry surface 9 is totally reflected, in the direction of a light transfer area 12 of the light supply channel 2', 2'', 2''', at which the light is transferred from the light supply channel 2', 2'', 2''' to the first narrow side 4 of the planar light guide element 1. The light transfer area 12 of the light supply channels 2', 2'', 2''' is directly connected to, or merges into, the first narrow side 4 or the light coupling section 8, without any air gap between the light supply channel 2', 2'', 2''' and the light guide element 1. The light supply channels 2', 2'', 2''' are integrally connected to the planar light guide element 1. As from the Fig. 1 and Fig.As can be seen in Figure 2, the light sources 2', 2'', 2''' are arranged on a common circuit board 13, which runs in the extension direction E of the first narrow side 4 of the planar light guide element 1.

[0025] The light entry surface 9 of the light supply channels 2', 2'', 2''' has a contour adapted to the light source 10', 10'', 10''', so that a relatively high luminous flux can be captured from the light source 10', 10'', 10'''.

[0026] In the present embodiment, the first light supply channel 2' and the second light supply channel 2'' are connected to each other in a light entry area 14. The two light supply channels 2' and 2'' form a pair of light supply channels that are partially connected to each other. This increases the stability of the light supply channels 2' and 2'', which project in pairs like fingers from the first narrow side 4. The two light supply channels 2' and 2'' extend in a V-shape, spreading outwards from the light entry surface towards the first narrow side 4 of the planar light guiding element 1.

[0027] Since a light entry surface 9' of the first light supply channel 2' is located directly adjacent to a light entry surface 9'' of the second light supply channel 2'', a portion of the light emitted by the first light source 10' can be coupled into the second light supply channel 2'', and a portion of the light emitted by the second light source 10'' can be coupled into the first light supply channel 2'. It is understood that only a smaller proportion of the light emitted by the light source 10' or 10'' enters the unassigned adjacent light supply channel 2'', 2'. This results in a more uniform and wider illumination in the planar light guide element 1.

[0028] It is evident that light of different colors can be coupled alternately along the extension direction E of the first narrow side 4. Preferably, adjacent light transfer areas 12', 12'', 12''' of the light supply channels 2', 2'', 2''' are arranged at the same distance from each other. In the present embodiment, a distance b between the light transfer areas 12' and 12'' of the pair of light supply channels 2', 2'' is greater than a distance a between the light transfer area 12'' of the second light supply channel 2'' and the light transfer area 12''' of the third light supply channel 2'''. A diameter d of the light transfer areas 12', 12'', 12''' of the light supply channels 2, 2', 2'', 2''' corresponds essentially to the thickness of the planar light guiding element 1 or to the distance between the flat sides 5.

[0029] In the present embodiment, the light supply channels 2, 2', 2'', 2''' extend conically towards the free end 9, 9', 9''. This creates an adaptation to the dimensions of the light sources 10', 10'', 10''' on the one hand and the required thickness d of the planar light guiding element 1 on the other.

[0030] According to an alternative embodiment of the invention, which is not shown, the light supply channels 2 can run exclusively in straight lines, so that optical axes of the light sources run perpendicular to the light coupling section 8 or the light coupling side 4.

[0031] Preferably, the end-side light transition areas 12', 12'', 12''' of the light supply channels 2, 2', 2'', 2''' are each inclined or bent to the same side. In this way, the light sources 10', 10'', 10''' can be arranged on a common circuit board 13.

[0032] The light supply channels 2, 2', 2'', 2''' preferably have the same length. Reference symbol list 1 flat light guiding element 2, 2', 2'', 2''' light supply channels 3 Light coupling area 4 1. Narrow side 5 flat side 6 2. Narrow side 7 Light output area 8 Light coupling section 9, 9', 9'', 9''' Light entry area 10', 10'', 10''' Light source 11 Surface area 12`,12'',12'' Light transmission area 13 Circuit board 14 Light entry area E Extension direction d thickness and diameter

Claims

[1] Lighting device for vehicles with a planar light guide element (1), - which has opposite flat sides (5) on which coupled light is totally reflectable, - which in a light coupling area (3) has a first narrow side (4) for coupling in light emitted by a light source (10', 10'') arranged in the light coupling area (3), wherein coupling means assigned to the light sources (10', 10'') are provided on the first narrow side (4), - which has a second narrow side (6) in a light extraction area (7) for extraction of the light, that the first narrow side (4) of the planar light guiding element (1) is at least partially planar, that a number of light supply channels (2, 2', 2'') corresponding to the number of light sources (10', 10'') project from the first narrow side (4) of the planar light guiding element (1), at the free ends of which a light entry surface (9, 9', 9'') is provided, at which the light emitted by the light source (10', 10'') enters the light supply channel (2, 2', 2''), and at the second end of which, facing the first narrow side (4) of the planar light guiding element (1), a light transition area (12', 12'') is provided, from which the light in the respective light supply channels (2, 2', 2'') entered light is transferred to the first narrow side (4) of the planar light guiding element (1), characterized by, that two adjacent light supply channels (2', 2'') are connected to each other in a light entry area (14) of the same, wherein the two light supply channels (2', 2'') run in a V-shape with spreading of the same from the light source side in the direction of the first narrow side (4) of the planar light guiding element (1). [2] Lighting device according to claim 1, characterized by , that the light entry surface (12', 12'') of the light supply channel (2, 2', 2'') has a contour adapted to the light emission characteristics of the light source (10', 10''). [3] Lighting device according to claim 1 or 2, characterized by , that the light supply channel (2, 2', 2'') runs in a straight line and / or an arc. [4] Lighting device according to any one of claims 1 to 3, characterized by, that the light supply channel (2, 2', 2'') runs in an arc shape at a right angle, so that an optical axis of the light source (10', 10'') runs parallel to the first narrow side (4) of the planar light guide element (1) or at an angle between 20° and 90° to the first narrow side (4) of the planar light guide element (1). [5] Lighting device according to any one of claims 1 to 4, characterized by , that the first narrow side (4) of the planar light guiding element (1) has a plurality of stepwise arranged planar light coupling sections (8), from each of which an equal number and / or shape of light supply channels (2, 2', 2'') project, wherein the light entry surfaces (9, 9', 9'') of the light supply channels (2, 2', 2'') assigned to the light coupling sections (8) are assigned light sources emitting different light colors. [6] Lighting device according to any one of claims 1 to 5, characterized by, that the light transfer areas (12', 12'') of the light supply channels (2, 2', 2'') assigned to the light coupling sections (8) are arranged next to each other in the extension direction (E) of the light coupling section (7) and / or that the light transfer areas (12', 12'') of adjacent light supply channels (2, 2', 2'') of the light coupling sections (8) are arranged at an equal distance (a, b). [7] Lighting device according to any one of claims 1 to 6, characterized by , that the light supply channel (2, 2', 2'') is cylindrical in shape. [8] Lighting device according to any one of claims 1 to 7, characterized by , that the light supply channel (2, 2', 2'') tapers conically towards the light entry surface (9, 9', 9'') of the same.

Images