WO2015086307A1

WO2015086307A1 - Motor-vehicle lighting device

Info

Publication number: WO2015086307A1
Application number: PCT/EP2014/075506
Authority: WO
Inventors: Henning Hogrefe
Original assignee: Automotive Lighting Reutlingen Gmbh
Priority date: 2013-12-13
Filing date: 2014-11-25
Publication date: 2015-06-18
Also published as: EP3080513B1; DE102013225950A1; EP3080513A1; DE102013225950B4

Abstract

The invention relates to a motor-vehicle lighting device, comprising at least one plate-shaped, flat optical waveguide, which has a first light-conducting surface, a second light-conducting surface, and narrow sides, wherein a first region of the narrow sides is designed as a light outlet surface and a second region of the narrow sides is designed as a reflector, wherein the reflector is designed to direct part of the light coupled into the optical waveguide by a light source in the direction of the light outlet surface. According to the invention the lighting device has a plurality of such optical waveguides, which are arranged in the manner of a stack in such a way that the light-conducting surfaces of adjacent optical waveguides contact each other in a passage region and that the optical waveguide of the plurality of optical waveguides whose light outlet surface is arranged near a reference axis characterizing the lighting device is designed to concentrate the light coupled into said optical waveguide in such a way that a light distribution has a brightness maximum lying in the area in front of the lighting device.

Description

Automotive lighting device

The invention relates to a motor vehicle lighting device according to the preamble of claim 1.

Such a motor vehicle lighting device with at least one plate-shaped flat light guide is known from DE 10 2011 089 481 A1. The light guide described therein has a first Lichtleitfläche, one of the first Lichtleitfläche opposite the second Lichtleitfläche and between an edge of the first Lichtleitfläche and an edge of the second Lichtleitfläche and the first Lichtleitfläche with the second Lichtleitfläche connecting narrow sides. A first region of the narrow sides is formed as a light exit surface, a second region of the narrow sides is formed as a reflector. Furthermore, the light guide has a reflection surface, wherein the reflection surface is a depression in one of the two light guide surfaces, which extends into the light guide up to a certain depth. A light source is arranged so that light emanating from it illuminates the reflection surface and is reflected by it radially. From this radially reflected light incident on the reflector light is deflected there twice. In this case, the direction of the incident light during the deflection is reversed so that the further path of the deflected light between the reflection surface and the opposite light guide surface passes. This is achieved with a roof-shaped or v-shaped cross-section of the reflector through which the return path of the reflected light is parallel to the path of the incident light. This light guide uses the coupled light very efficiently for homogeneous illumination of the light exit surface. The light guide described has narrow strip-like longitudinally extended light exit surfaces. The ratio of width to height is large at these light exit surfaces.

From US 2007/0145395 A1 a plate-shaped light guide is known, into which a light source arranged below the light source couples light. The light strikes a reflection surface arranged within the light guide, which reflects the incident light radially. The radially reflected light partially impinges on a reflector, which is a region of a narrow side of the light guide. Due to the curved shape of the reflector, the light is directed in the direction of the light exit surface. Here, the height of the light exit surface is determined by the height of the light guide. Light that is incident on the reflector near the vertex, starting from the reflection surface, is deflected only with losses to the light exit surface. The losses are caused by the fact that this light partly meets again on the reflection surface and is reflected at this or exits through refraction from the light guide.

From DE 199 25 363 A1 discloses a plate-shaped flat trained light guide is known. The light guide has a circular recess, in the center of which a light source is arranged. Light emanating from the light source is coupled into the light guide via the boundary surfaces of the recess. An area of the narrow side of the light guide is designed as a reflector. The reflector is shaped so that incident light is directed in the direction of a light exit surface. For this purpose, the reflector has a parabolic or elliptical shape. The disadvantage here is that light which impinges on this in the vicinity of a vertex of the reflector, is reflected back to the circular recess and thus does not or only partially reaches the light exit surface. This is therefore not homogeneous, that is illuminated with location-independent same brightness. In addition, here too the height of the light exit surface is determined by the height of the light guide plate. As a result, the light exit surface is strip-like.

From DE 102 34 110 A1 it is known to arrange a plurality of light guide bodies, each of which has a light source associated with it, next to one another. At the light exit surface of each light guide further light guide in the form of Lichtleitstäben are arranged, whose light exit surfaces form a common matrix-like exit surface.

From EP 1 850 064 A1, a lighting device is known, which has a pile-like stacked, plate-shaped light guide.

Already known light guides are very efficient in terms of lighting, but have a flat, elongated light exit surface. In particular, it is problematic to achieve a light distribution in an apron of a motor vehicle with the said lighting devices, which has an illuminance curve of a certain desired shape from the center to the edges of the light distribution. An illumination intensity profile of a desired shape is required, for example, in the case of a rule-conforming spotlight distribution. A low-beam distribution or a high-beam distribution are examples of such a headlight distribution without the enumeration being meant conclusively.

Against this background, the object of the invention in the specification of a lighting device of the type mentioned, in which a large area exit surface is homogeneously illuminated by means of efficient light guide and the rule-compliant light distribution with a rule compliant light distribution corresponding illuminance profile can be generated.

The object is achieved by a motor vehicle headlight with the features of claim 1.

The illumination device according to the invention is characterized in that it comprises a plurality of light guides described in the preamble of claim 1, which are arranged in a stack so that the light guide surfaces of adjacent light guides touch at least in a transition region which is close to the light exit surface of at least one of the touching Light guide is located.

In this way, the respective flat, elongated light exit surfaces of the plurality of optical fibers in the vertical direction stacked on one another form a large common exit surface. In particular, it is provided that the one of the plurality of optical waveguides whose light exit surface is arranged near a reference axis characterizing the illumination device is adapted to concentrate the light coupled into it such that a light distribution generated by the illumination device has a brightness maximum lying in advance of the illumination device.

By the term "reference axis" is meant an axis characterizing the axis here. The legislator stipulates that the reference axis is specified by the manufacturer as an axis which serves as the reference direction (H = 0 °, V = 0 °) for the regulation-compliant mounting of the illumination device on the vehicle and as reference direction for the angles in the photometric measurements. H stands for the horizontal direction and V stands for the vertical direction. Consequently, the reference axis passes through the intersection of the major axes H, V of the rule-compliant light distribution.

The reference axis is expediently chosen such that it lies parallel to a main light exit direction of the illumination device. In lighting devices that have an imaging optics, often the optical axis of this imaging optics is selected as the reference axis.

In an advantageous embodiment it is provided that at least one of the plurality of plate-like optical fibers has a reflection surface, wherein the reflection surface is a rotationally symmetrical recess in one of the two Lichtleitfläche extending to a certain depth in the light guide and wherein the at least one light source arranged in that its light is coupled into the optical waveguide via the light guide surface opposite the depression and falls onto the reflection surface, the reflection surface being adapted to radially reflect light incident thereon, so that the rays propagate at shallow angles in the light guide and from Depending on the direction of the radial reflection, optical fibers can either be directed directly to the exit surface or be first deflected by the reflector on the narrow side, in order to then also be directed to the exit surface.

On the narrow side, the reflection takes place for example on a prism-like reflector, a so-called roof edge reflector, such that incident light is deflected twice and reversing the direction of the incident light is reversed so that the further path of the deflected light between the Well and the opposite light guide surface passes. Such designed light guides use the coupled-in light particularly effective for illuminating their light exit surface.

An advantageous embodiment is that an imaging optics is set up and arranged to direct light emerging through the light exit surfaces into the apron of the illumination device and that the light exit surfaces of the light guides are arranged in a region near the object-side focal surface of the imaging optics, in particular an imaging lens. It is preferably provided that the light exit surfaces of one or more light guides are arranged at a distance of up to a few millimeters from this focal surface. As a result, this light exit surface is not sharply imaged in the resulting light distribution. In the blurred image, bundles of rays emanating from different light exit surfaces overlap, giving the observer the impression of a large, uniformly illuminated exit surface.

It is also advantageous that at least one of the optical fibers in contact with the transition region is adapted to allow light propagating in it to emerge in such a way that it partially mixes with the light originating from an adjacent optical fiber. This gives the viewer the impression of a large and homogeneously illuminated exit surface. The mixing of the beam paths is achieved by suitable measures. For example, the contact surfaces of the respective optical waveguides are locally connected to one another in terms of light, so that light in the transition region near the light exit surface transitions from one optical waveguide into the other optical waveguide.

Furthermore, it is proposed that at least one of the plurality of light guides in subregions of its light exit surface or in subregions which lie close to its light exit surface have structures which are suitable for scattering the light propagating in the light guide. The scattered light of the individual light guides superimposed in the transition region near the light exit surfaces, so that the individual light exit surfaces appear together as a large homogeneous luminous exit surface.

It is preferred that the light exit surface of at least one of the plurality of stacked optical fibers is arranged below the reference axis of the illumination device. The light emanating from this light exit surface is imaged by the imaging optics in the apron of the illumination device above the reference axis. This produces a light distribution which has an illumination above a middle horizontal. In this way, for example, a high beam distribution is generated.

Furthermore, it is preferred that a diaphragm is arranged between the light exit surfaces and the imaging optics. The aperture is fixed or movable. The diaphragm has an aperture edge which lies in the object-side focal surface of the imaging optical system or can be moved into it so that the diaphragm completely or partially obscures light exit surfaces which are arranged below the optical axis of the imaging optical unit. The diaphragm edge is imaged by the imaging optics as a light-dark boundary in the apron of the illumination device. Thus, for example, a low-beam light distribution can be generated.

A further preferred embodiment provides that the light exit surface of at least one of the plurality of light guides is arranged in the object-side focal surface of the imaging optics. This light exit surface is then sharply imaged in the apron of the motor vehicle, so that the edge of the first light guide surface or the edge of the second light guide surface serves as a light-dark boundary.

Furthermore, it is preferred that a fixed diaphragm is arranged between the light exit surfaces and the imaging optics. The fixed aperture window-like limits the light exit surfaces of all the stacked optical fibers, so as to produce a desired appearance of the entire exit surface. In addition, portions of the light guides or their light exit surfaces, which should not be visible, are covered by the diaphragm. The fixed bezel can be used with the movable bezel.

A further embodiment provides that in at least one of the plurality of optical fibers, the first light guide surface and / or the second light guide surface form an angle with the light exit surface, which is not a right angle. It is also preferred that the first light-guiding surface and / or the second light-guiding surface have an angle not equal to zero degrees relative to one another over at least a partial region of their longitudinal extent, so that the thickness of the plate-shaped light conductor uniformly changes in the direction of the exit surface. In this case, either the light exit surface preferably deviates from a vertical position, or one of the two light guide surfaces or both light guide surfaces deviates from a horizontal position. In addition, the light exit surface of all or individual light guides can deviate from the vertical position. Depending on the combination different lighting effects can be achieved. Here are a few of them enumerated and described, without the enumeration is meant conclusively.

If, for example, the light exit surface is tilted upwards against the direction of light exit from the vertical, the exiting light is directed downwards with respect to the horizontal. A tilting of the light exit surface above in the light exit direction from the vertical leads to a deflection of the exiting light upwards with respect to the horizontal.

Tilting of one or both light guide surfaces, which occurs in such a way that the light guide tapers in vertical planes (y-z planes) towards the light exit surface, causes the radiation beam to expand. The widening can be effected in such a way that the beams of the individual optical fibers are already superimposed in the transition region or take place only after passing through the light exit surfaces.

Tilting of one or both light guide surfaces, which takes place in such a way that the light guide widens in vertical planes (y-z planes) toward the light exit surface, results in that the aperture angle of the radiation beam is reduced.

The above-described positions of the light guide surfaces and the light exit surface to each other and / or to the main axes and combinations thereof and also the vertical and lateral extent of the light exit surfaces, as well as the shape of the reflector and the reflection surface are adapted to produce a desired, compliant light distribution.

A further embodiment provides that the plurality of optical fibers are arranged inclined to each other, so that their light exit surfaces are arranged radially about a horizontal axis. As a result, on the one hand, the light bundles emerging from the individual light exit surfaces are aligned with regard to their position to the total light distribution, on the other hand one gains space in the region of the light entry ends of the individual light guides, for example, to arrange heat sinks or the like.

A further advantage is that a light entry end of at least one of the plurality of optical fibers is angled relative to the transition region near the light exit surface by an angle with respect to the reference axis. The angle is preferably 90 °. This "cranked" design of the light guides, causes their expansion is reduced in the direction of the reference axis with respect to planar light guides, whereby a particularly compact design of the lighting device is possible in this direction.

It is also advantageous that at least one of the light guides is designed stepwise in the direction of the reference axis. In the stepped optical waveguide, the light is deflected to another plane. The step-like shape of the light guide or facilitates the installation in existing housing. In order to meet different installation conditions, it is also preferred that the light guide is curved in its extension along the reference axis.

A further embodiment provides that at least one of the light guides is curved in its horizontal extent along a horizontal axis transverse to the reference axis and in the intended use. As a result, a greater freedom is achieved for the design of the light exit surface.

It is also preferred that the light sources can be controlled separately from one another and / or emit light of different color and / or different intensity in order to realize different light or luminaire functions with the same common exit surface.

It is also preferable that at least one of the plurality of optical fibers have structures on which the light is directed in desired directions. The structures are, for example, interfaces of recesses in the optical waveguide, at which internal total reflections take place, and / or it is the narrow sides which delimit the optical waveguide. An internal total reflection of the incident light also takes place on these surfaces. The surfaces are shaped so that the reflected light is directed in desired directions. In an alternative or additional embodiment, the recesses form so-called air lenses. In these air lenses, the light propagating in the optical fiber passes through the recess in the optical fiber. When passing through the interface, the light is directed by refraction in desired directions. By means of these internal structures, for example, a light guide is provided which allows both a good focusing of the light in the direction of the reference axis, and also allows a certain illumination of edge areas.

A preferred embodiment provides, in addition to the light exit surfaces of the stacked light guide further light exit surfaces are arranged so that their light exit surfaces are arranged so that their light exit surfaces are the same height with respect to a transverse axis to the reference axis and the intended use vertical axis as at least one light exit surface of the stack arranged light guide. These adjacent light exit surfaces are, for example, the light exit surfaces of preferably plate-shaped light guides, which are arranged in the same horizontal plane as one of the stacked light guide.

Alternatively, it is also conceivable that one of the stacked optical fibers is further extended in the horizontal direction, as the example, immediately adjacent thereto arranged light guide. Areas of the first, upper light guide surface, which are not covered by the light guide arranged above, thereby have a height with respect to the y-axis, which is greater than the height of the second, lower light guide surface of the light guide arranged above. The light guide arranged above is embedded in the light guide arranged underneath. Lateral areas of the light exit surface of the surrounding, here the lower light guide, are designed so that they, viewed in the horizontal, are arranged next to the light exit surface of the embedded light guide.

In a similar embodiment, a light guide arranged below is embedded in the adjacent, above-arranged light guide, so that the light exit surface of the embedded light guide is surrounded above and laterally by the light exit surface of the above adjacent light guide.

Such designed and arranged light exit surfaces allow a flexibly shaped, common exit surface.

A further embodiment provides that at least one of the plurality of stacked optical fibers is fed with light from a plurality of light sources. Several light sources, whose light is coupled into the same light guide, increase the intensity of the light distribution generated by the light guide.

In addition, it is proposed that each light guide is fed with light from at least one light source. As a result, the entire exit surface, composed of the light exit surfaces of the individual plate-like light guides, efficiently illuminated homogeneously.

It is understood that the features mentioned above and those yet to be explained below are applicable not only in the particular combination given, but also in other combinations, without departing from the scope of the present invention.

Embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description. In this case, the same reference numerals in the various figures denote the same elements. It branches, each in schematic form:

Figure 1: a light guide according to the prior art in a perspective view;

Figure 2: a lighting device according to the invention in vertical section view;

FIG. 3 shows a first embodiment of a plurality of stacked light guides in vertical section;

FIG. 4 shows a second embodiment of a stacked optical waveguide in vertical section;

FIG. 5 shows a third embodiment of a stacked optical waveguide in vertical section;

FIG. 6 shows a stack-like arrangement of a plurality of cranked light guides in vertical section;

FIG. 7 shows a stack-like arrangement of a plurality of optical waveguides and a diaphragm in vertical section;

FIG. 8 shows a stack-like arrangement of a plurality of optical waveguides and an imaging optical system in a horizontal sectional representation;

Figure 9: a structure having optical fiber in horizontal section view;

Figure 10: a light guide, coupled into the light of multiple light sources, in vertical section view;

FIG. 11 shows a further embodiment of a light guide in which light from several light sources is coupled in vertical section; and

FIG. 12 shows a further embodiment of a light guide in which light from several light sources is coupled in vertical section.

FIG. 1 shows a plate-shaped flat optical waveguide 10 according to the prior art. The optical waveguide 10 is delimited by a first light guide surface 12, a second light guide surface 14 lying opposite the first light guide surface 14 and an edge 16 of the first light guide surface 12 and an edge 18 of the second light guide surface 14 and connecting the first light guide surface 12 to the second light guide surface 14 , The dimensions of the first light guide surface 12 and the second light guide surface 14 in relation to the dimensions of the narrow sides 20 characterize the appearance of the light guide 10 as a light guide plate.

A first region of the narrow sides 20 is formed as a light exit surface 22. The light exit surface 22 is strip-shaped and elongated. A length of the light exit surface is large compared to its width (height). This means that the length (in the x direction) is at least five times the width (height) (in the y direction). A second region of the narrow sides 20 is formed as a reflector 26.

Furthermore, the light guide 10 has a reflection surface 24. The reflection surface 24 is formed as a recess tapered from outside to inside in one of the two light guide surfaces 12 or 14. In the light guide 10 shown in FIG. 1, the depression in the first light guide surface 12 is arranged between the light exit surface 22 and the reflector 26 and extends into the light guide 10 up to a certain depth. A light source 34 is arranged opposite the tip of the recess on the second light guide surface so that light emanating from it illuminates the reflection surface 24 and is reflected radially by it. From this radially reflected light incident on the reflector 26 light is deflected there in the direction of the light exit surface 22. It is also preferred that the reflection surface 24 is specially shaped such that light emitted by the light source 34 is reflected substantially radially to the side, but not uniformly in all directions. Thus, it is for example possible to illuminate certain areas of the reflector 26 and / or the light exit surface 22 reinforced.

The light source 34 is arranged outside the light guide 10 at a small distance therefrom. The light source 34 is usually designed as a light-emitting diode (LED) and arranged on a carrier element 36, so that their main emission direction is opposite to the y-axis direction of an imaginary coordinate system and points to the light guide surfaces. The z-axis of the coordinate system points in the main emission direction of the optical waveguide 10 and thus, when the optical waveguide is used as intended in a motor vehicle illumination device, in an apron of the motor vehicle.

Here, the z-axis is identical to a reference axis to be defined by the manufacturer of the illumination device. The reference axis serves as a reference direction for the rule-compliant light distribution. The reference axis passes through the intersection of the main axes (H = 0 °, V = 0 °) of the rule-compliant light distribution. In lighting devices that have an imaging optics, often the optical axis of this imaging optics is selected as the reference axis.

The longitudinal extent of the strip-shaped light exit surface is parallel to the x-axis of the coordinate system. In a proper installation of the light guide in a motor vehicle lighting device, the x-axis is parallel to the horizon and is therefore hereinafter also referred to as horizontal, the y-axis is to be understood as a vertical meaning. The imaginary coordinate system retains its alignment in all subsequent figures.

FIG. 2 shows, inter alia, another embodiment of the light guide 10. In contrast to the light guide 10 shown in FIG. 1, here the reflection surface 24 is a depression in the second light guide surface 14. The light source 34 is arranged opposite to the first light guide surface 12. so that their main emission direction is parallel to the y-axis of the imaginary coordinate system. The terms "first light guide surface 12" and "second light guide surface 14" are not associated with a position of the reflection surface 24 or the associated light source 34, but with the orientation of the light guide 10 in space. In the direction of the y-axis, the second light-guiding surface 14 follows the first light-guiding surface 12. That is to say that the first light-guiding surface 12 can also be referred to as the upper light-guiding surface 12 and the second light-guiding surface 14 as the lower light-guiding surface 14.

The operation of the light guide 10 is as follows: From the light source 34 outgoing light passes through the upper Lichtleitfläche 12 in the light guide 10. A portion of the incoming light strikes the reflection surface 24 and is deflected at this radially so that the rays now predominantly below flat angles, so almost parallel to the light guide surfaces 12, 14 of the light guide 10 in the light guide 10 propagate. A part of the incident light is directed towards the light exit surface 22, another part of the incoming light is deflected in the direction of the reflector 26.

In contrast to Figure 1, the reflector 26 of the light guide 10 is formed in Figure 2, for example, as a roof edge reflector. The roof edge reflector redirects the incident light twice. In particular, the reflector 26 is formed so that during the deflection, a reversal of the light direction and that the further path of the deflected light, offset parallel to the path of the incident light, between the recess of the reflection surface 24 and the recess opposite light guide surface 12 therethrough leads. Thus, an effective homogeneous illumination of the light exit surface 22 is achieved.

The first light guide surface 12 and the second light guide surface 14 transport the light by total internal reflection (TIR) in the direction of the light exit surface 22.

Both the embodiment of the optical waveguide 10 shown in FIG. 1 and the embodiment of the optical waveguide 10 shown in FIG. 2 are used in a motor vehicle lighting device according to the invention. In the embodiments explained below with reference to FIGS. 2 to 12, the embodiments of the optical waveguide 10 described with reference to FIGS. 1 and 2 are predominantly illustrated, without the invention being restricted thereto. Also conceivable is the use of plate-shaped flat designed light guides, coupled into the light in other than the manner described.

Figure 2 shows a motor vehicle lighting device 38 according to the invention. In a housing 40, the light exit opening is covered with a transparent cover 42, several, here three, optical fibers 10.1 to 10.3 arranged in a stack. The arrangement of the light guides 10.1 to 10.3 is such that a first light guide surface 12 of one of the plurality of light guides 10 is adjacent to the second light guide surface 14 of the adjacent light guide 10. At least in a transition region 44 near the light exit surfaces 22 touching adjacent light guide 10th

Each of the plurality of optical fibers 10 is associated with a light source 34 whose main emission direction is opposite to the y-axis of the imaginary coordinate system.

It is preferred that the motor vehicle lighting device 38 has imaging optics. The imaging optics is preferably an imaging lens 46. The imaging optics is arranged between the light exit surfaces 22 of the light guides 10 and the cover plate 42. In an embodiment of the imaging optics as imaging lens 46, this is preferably designed as an aspherical, rotationally symmetrical lens, as is known from conventional projection systems. Also conceivable is the use of a cylindrical lens, a toric lens, a Fresnel lens or a lens system of a plurality of individual lenses.

In the cylindrical lens, one or both refracting surfaces have the shape of a cylinder shell segment. Therefore, the cylindrical lens focuses on incident parallel light on a focal line instead of a focal point as is the case with the aspheric or rotationally symmetric lens.

The toric lens has two different powers, or more generally, two different deflection characteristics in two perpendicular directions. One of the lens surfaces has the shape of a surface portion of a torus.

In the illustrated embodiment, the imaging lens 46 is designed as a separate part. In another embodiment, the imaging lens is part of the optical waveguide 10. This can be realized, for example, by correspondingly shaped light exit surfaces 22.

The embodiments and modes of operation of the illumination device 38 shown and described below are preferably implementable with imaging optics, but are not limited to the presence of imaging optics 46.

The course of the optical paths within each of the plurality of optical fibers 10 is substantially as described above with reference to FIG. 1 or FIG. Due to the stack-like arrangement of the light guides 10, their light exit surfaces 22 are stacked one above the other so that a plurality of strip-shaped and elongated light exit surfaces together form an exit surface 48 which has a smaller length-to-width ratio than the single strip-like light exit surface 22.

In order to achieve the most uniform possible luminous exit surface 48, it is preferred that the beam paths in the individual optical fibers 10 do not run completely parallel to the first optical fiber surface 12 and the second optical fiber surface 14 by suitable measures, and thus a certain overlap of the optical paths of the individual optical fibers 10 in FIG the transition regions 44 takes place in the vicinity of the light exit surface 22.

The imaging optics 46 is configured to image the common exit surface 48 formed by the individual light exit surfaces 22 into the apron of the illumination device 38 and thus to generate a light distribution that complies with the rules for a light function of a motor vehicle. The imaging optics 46 forms the exit surface 48 upside down and laterally reversed. The imaging optics 46 are typically formed as lenses or lens systems that are more or less affected by aberrations that increase with increasing distance from the optical axis z of the imaging optics 46. For these reasons, there are various possibilities for the arrangement of the light exit surfaces 22 relative to each other and in relation to the imaging optics 46 and as a function of the light function to be represented by the illumination device 38.

FIGS. 3 to 6 show various options for arranging optical fibers 10 in a stack. All embodiments have in common that that light guide 10 whose light exit surface 22 has the greatest luminance, in the direction of the y-axis as close as possible to the optical axis, here the z-axis, the imaging optics 46 is arranged. In this way, the requirement of rule-compliant light distribution that the brightness maxima are to be in the middle of the light distribution, the best possible.

For a light distribution which requires a good illumination or a brightness maximum below and above the horizontal main axis of the light distribution, such as a high beam distribution, an arrangement of the optical fibers 10 according to FIG.

FIG. 3 shows an arrangement of the light guides 10.1 to 10.3 according to FIG. 2. In addition, a further light guide 10.4 is arranged below the optical axis, here the z-axis, of the imaging optics. In the exemplary embodiment illustrated, the light source 34.4 assigned to the light guide 10.4 is arranged on the second light guide surface 14.4. The recess of the first reflector 24.4 is arranged on the opposite first light guide surface 12.4. The light source 34.4 thus radiates against the direction of the y-axis in the light guide 10.4. An arrangement of the light source 34.4 on the first light guide surface 12.4 is also possible, so that it radiates into the light guide 10.4 counter to the y-axis direction. The depression of the first reflector 24.4 is then to be arranged opposite in the second light-guiding surface 14.4.

The light exit surface 22.4 of the further light guide 10.4 lies below the optical axis and is therefore imaged by the imaging optics 46 in the apron above the horizontal axis, so that, for example, a high beam distribution can be represented by the further light guide 10.4.

FIG. 4 shows a stack-like arrangement of three light guides 10.1 to 10.3. The first light guide 10.1 has a first light guide 12.1 and a second Lichtleitfläche 14.1, which are not parallel to each other, but here in the direction of the y-axis are inclined to each other and thus cause a uniform taper of the light guide 10.1 in the z-axis direction. By the taper of the light guide, the vertical extent of the light exit surface is reduced, whereby it is possible to produce a brightness maximum in a desired range of light distribution. The desired Beeich is preferably the remote zone of the light distribution. The light bundle transported by the total internal reflection at the inclined light guide surfaces thus experiences an expansion in the yz plane. The unwanted expansion of the light bundles causes a part of the light emerging through the light exit surface 22 from the imaging lens 46 is not directed into the light distribution.

Overall, in one embodiment of the illumination device 38, which has an imaging optics 46, an optical waveguide 10 is advantageous, or whose light exit surface 22 has the smallest possible vertical extent. This applies in particular to optical fibers which are arranged as close as possible to the reference axis z. As the distance from the reference axis z increases, this vertical extent may increase.

An extension of the light guide 10.1 in the direction of the z-axis is also conceivable. The first light guide surface 12.1 and the second light guide surface 14.1 are inclined away from each other in the y-axis direction. The light beam reflected on them by internal total reflections undergoes a reduction in its opening angle in the y-z plane. It is therefore achieved a reduction in the opening angle of the light emanating from the light source 10.1 in the vertical direction.

The rejuvenation or amplification of the light guide plates 10 takes place as steadily as possible and the angles of inclination of the light guide surfaces are small. Thus, a loss of the incident light due to unwanted leakage through the light guide surfaces is largely avoided.

Ideally, to avoid the optical effects of tapering or amplification of the optical fiber, each optical fiber should be made approximately constant in thickness over its entire extent. The thickness of one of the plurality of optical waveguides 10 is the same as or different from the thickness of another of the plurality of optical waveguides 10. Thus, for example, it is preferable that the thickness of the plurality of stacked optical fibers 10 and thus the vertical extent of their respective light exit surface 22 with increasing distance in vertical direction of the reference axis increases.

It is also conceivable that each of the light guides 10.1 to 10.3 has a steadily increasing or decreasing thickness in the z-axis direction.

FIG. 5 shows three light guides 10.1 to 10.3, which are arranged in a stack such that the first light guide surface 12 of one of the plurality of light guides 10 is adjacent to the second light guide surface 14 of the adjacent light guide 10 and touch only in a transition region 44 near the light exit surface 22. The light exit surfaces 22 opposite light entry ends 50 of the light guide plates 10 are further spaced from each other. This results in a common exit surface 48 curved in the yz plane. On the one hand, the light bundles emerging from the individual light exit surfaces 22 are aligned in their position relative to the total light distribution, and on the other hand, one gains an index in the region of the light entry ends 50 , which numbers the optical fibers of the stack, for example, from i = 1 to 3) of the individual optical fibers 10.1 to 10.3 with respect to a purely horizontal orientation of the optical fibers 10 space to order, for example, heat sinks to the light sources 34.

FIG. 6 shows a stack-like arrangement of light guides 10.1 to 10.3, the first light guide surface 12 of one of the plurality of light guides 10 being adjacent to the second light guide surface 14 of the adjacent light guide 10 and these two light guide surfaces being located in a region 44 near the light exit surface 22 touch. Each of the plurality of optical fibers 10 is executed angled. The light entry end 50 of each light guide plate 10, on which the first reflector 24 and the first reflector 24 opposite, the light source 34 are arranged, is bent against the transition region 44 by an angle α. In the illustrated embodiment, the angle α is equal to 90 °. The light source 34 radiates here in the direction of the z-axis direction into the associated light guide 10, wherein a main light exit direction through the light exit surface 22 is substantially in the z-axis direction. Since in the illustrated embodiment, the extension of the light guide 10 in the direction of the z-axis is small compared to other embodiments, this allows a particularly compact design of the illumination device 38 in this direction.

7 shows a further embodiment of the stack-like arrangement of a plurality of optical fibers 10.1 to 10. 4 is shown. Of the optical fibers 10.1 to 10 4, only the transition regions 44 near the light exit surface 22 are shown. The ends 50 of the light guides 10, on which the first reflector 24, the light source 34 and the second reflector 26 are arranged, are not shown in FIG. The first light guide surface 12 of one of the plurality of light guides 10 is arranged adjacent to the second light guide surface 14 of the adjacent light guide 10. Adjacent light guide plates 10 contact each other in the transition region 44 near the light exit surface 22. In the contact surface, the light guides are preferably welded or glued together or in optical contact with each other through an optical oil distributed between them so that light from one optical fiber passes into the other light guide can. Each of the light guide plates 10 is arranged at least one light source 34 so assigned that the respective light guide plate is fed with light from this light source. FIG. 7 shows various measures of the design in the area of the light exit surfaces. These measures affect the homogeneity and / or the fine-tuning of the light distribution and are applicable to all embodiments of the illumination device 38.

The first light guide plate 10.1 is arranged on the z-axis so that the main emission direction is through the light exit surface 22.1 in the direction of the z-axis. The further light guide 10.4 is arranged along the y-axis below the first light guide plate 10. 1, so that the main emission is through its light exit surface 22.4 below the z-axis. The light exit surface 22.4 of the further light guide 10.4 and the light exit surface 22.1 of the first light guide 10.1 lie in the same plane perpendicular to the z-axis. The light exit surface 22.2 of the second light guide 10.2 and the light exit surface 22.3 of the third light guide 10.3 are offset along the z-axis relative to the light exit surface 22.1 and the light exit surface 22.4 to the rear. The light exit surface 22.3 and part of the light exit surface 22.2 are inclined to the right against the z-axis direction.

Between the light exit surfaces 22 and the imaging optics 46, not shown in Figure 4, a diaphragm 52 is rotatably disposed about an axis. The aperture 52 is positioned so that an aperture edge 54 is pivotable in the vicinity of the object-side focal surface of the imaging optics 46. This first end position of the diaphragm 52 is shown in FIG. 4 by means of solid lines. The diaphragm edge 54 is imaged in the first end position as a light-dark boundary in the light distribution in the apron of the motor vehicle, so that it fulfills a rule-compliant low-beam function. A second end position 56 of the diaphragm 51, in which the diaphragm edge 54 is pivoted out of the main light exit direction and thus is not imaged in the light distribution, is indicated in FIG. 7 by dashed lines.

In the illustrated embodiment, the individual light exit surfaces 22 of the light guides 10 are arranged at different distances Δz not equal to 0 from the object-side focal surface. As a result, the light exit surfaces 22 are not shown in focus. It creates a homogeneous light distribution.

Another embodiment provides that all light exit surfaces 22 are arranged at the same distance .DELTA.z from the object-side focal surface.

The light exit surface 22.3 of the third light guide 10.3, for example, from the vertical prism-like design in the drawing to the right inclined. This ensures that the light exit from this light exit surface 22.3 to the optical axis z out, as shown by the arrow 58. This ensures, on the one hand, that the position of a light beam emerging from the third light exit surface 10.3 in relation to the position of the other light exit surfaces 22.2, 22.1. 22.4 emerging light beam is changed in limits. Here, the light emerging through the light exit surface 10.3 is directed in the direction of the reference axis z. On the other hand, it is achieved that the light emerging from the third optical waveguide 10.3 at least partially mixes with the light emerging from the other optical waveguides 10.2, 10.1 and 10.4, thus producing a homogeneous light distribution.

By shifting a light exit surface by dz to the focal plane, the distribution of light, which emerges here, a little blurred. Due to the inclined regions of the exit surfaces, the position of the rays emerging there is changed vertically in the light distribution. In the case shown, the light is pushed a little closer to the center of the light distribution. These measures of changing dz or changing the inclination or the surface shape of the exit surfaces are also applicable in a different arrangement than shown here.

The measures explained with reference to FIG. 7, ie different distances of the light exit surfaces 22 from the object-side focal surface or inclination or surface shape of the light exit surface 22, can also be used in arrangements and combinations other than those shown here.

Other embodiments provide that the light exit surfaces 22 are shaped accordingly to guide and distribute the light emerging through them accordingly. In particular, the light guides 10 may have scattering profiles or scattering structures which are arranged on the light exit surface 22 or in a partial region of the light guide 10 near the light exit surface 22.

FIG. 8 shows the stacked light guides 10.1 and 10.2 of the illumination device 38 in a view from below. Shown is in particular the first light guide surface 12.1 of the plate-shaped flat first light guide 10.1 and the first Lichtleitfläche .2 of the view direction from below arranged above the second light guide 10.2. The first optical waveguide 10.1, in particular its reflector 26.1, is designed so that the light emanating from its associated light source 34.1 is focused toward the optical axis z of the exit optical system 46. The second optical waveguide 10.2 or its partially concealed by the first optical waveguide 10.1 reflector 26.2, however, is designed so that of the second light guide 10.2 associated light source, which is covered in the figure by the first light guide 10.1, outgoing light in the drawing plane, here the xz-plane, is parallelized. Accordingly, the light exit surface 22.1 of the first light guide 10.1 has a smaller longitudinal extension in the x direction compared to the light exit surface 22.2 of the second light guide 10.2

In another preferred embodiment, the first light guide 10.1 is virtually embedded in the second light guide 10.2. It is preferred that the light exit surfaces 22.2 of the second light guide 10.2 are arranged in the horizontal next to the light exit surface 22.1 of the first light guide 10.1.

Conceivable are also embodiments of the illumination device 38, which are arranged in addition to the plurality of stacked optical fibers 10, the first Lichtleitfläche 12 of one of the plurality of optical fibers 10 is adjacent to the second Lichtleitfläche 14 of the adjacent optical fiber 10 and in a transition region 44 touch the light exit surfaces 22, still have other plate-shaped light guide 10, which are arranged so that their first Lichtleitfläche 12 and / or second Lichtleitfläche 14 are at the same height with respect to the y-axis, as one of the

Lichtleitflächen

12 or 14 of the stacked optical fibers 10. It follows that the light exit surfaces 22 of the further optical fibers are arranged in the x direction next to the light exit surface 22 of one or more of the light conductors 10 arranged in a stack.

The optical waveguides 10 for use in the above-described embodiments may have structures that guide the light propagating in the optical waveguide 10. Such a light guide 10 is shown in FIG. The first light guide surface 12 lies in the plane of the drawing. The light guide 10 has a centrally arranged, in the form of a recess 60 realized lens and

individual deflection sections

62, 64, 66, 68, 70, 72, which are realized in particular as inner reflection sections.

In the illustrated embodiment, the central recess has two refractive interfaces 61, so that the recess acts like a diverging lens, which focuses the radially divergently incident light beams in the direction of the optical axis.

In another embodiment, central recess 60 is adapted to act with its refractive interfaces 61 as a converging lens.

The deflection sections are defined in part by

outer contours

62, 64 of the narrow sides 20 of the light guide 10. The arrangement of the deflection sections is preferably symmetrical to the optical axis z, which passes through the center of the light exit surface 22 and the second reflection surface 26.

The lying within the light guide 10

deflection sections

66, 68, 70 and 72 are realized as boundary surfaces of recesses in the light guide material and positioned, shaped and oriented so that they detect as many partial light bundles. The detected partial light bundles are focused and aligned. The outer reflector 26 illuminates part of the inner deflection surfaces and otherwise provides for the illumination of the lateral edge regions of the light distribution, in which the intensity gradually decreases from the inside to the outside.

Overall, the different configuration of the structures in the form of lenticular-acting recesses or diversely designed deflection sections offers a variety of possibilities for directing the light propagating within the light guide in such a way that a desired, rule-compliant light distribution is displayed.

FIGS. 10, 11 and 12 each show further embodiments of the optical waveguide 10. Each of the flat-shaped optical waveguides 10 shown in FIGS. 10 to 12 has the first light-guiding surface 12, the second light-guiding surface 14 opposite the first light-guiding surface 12, and between the edge 16 the first Lichtleitfläche 12 and the edge 18 of the second Lichtleitfläche 14 and the first Lichtleitfläche 12 with the second Lichtleitfläche 14 connecting narrow sides 20 on. A first region of the narrow sides 20 is formed as a light exit surface 22, and a second region of the narrow sides 20 is formed as a reflector 26. The reflection surface 26 is formed as a recess in one of the two light guide surfaces, which extends into the light guide 10 to a certain depth. The light source 34 is arranged to couple its light into the light guide 10 via the light guide surface opposite the recess and to fall onto the reflection surface 24, the reflection surface 24 being adapted to radially reflect light incident thereon, and the reflector 26 adapted thereto is to redirect light incident on him twice and reverse the direction of the light incident on him during the deflection, so that the further path of the deflected light between the reflection surface 24 and the light guide surface opposite him leads through. The light guides 10 illustrated in FIGS. 10 to 12 are characterized in that each light guide 10 is assigned at least two light sources 34.

The light guide 10 shown in FIG. 10 can be produced by having two partial light conductors, each having a connection surface, as shown in FIG. 10 as a dashed line T. The partial light guides are connected together along their connecting surface. The connection is made for example by gluing, laminating or fusing. In the non-connected state, the connection surface is the light guide surface in the serving as a reflection surface 24 recess.

FIG. 11 shows a further embodiment of a light guide 10, to which a plurality of light sources 34 are assigned. Here, the reflection surface 24 is a depression in the first light guide surface 12. On the side opposite to the first light guide surface 12, the light guide 10 has a recess second light guide surface 14 outstanding coupling projection 74 on. The coupling projection 74 is delimited by light entry surfaces 76. The light entry surfaces 76 are aligned substantially perpendicular to the Lichtleitfläche in the illustrated example. The light entry surfaces 76 are preferably formed as a circumferential cylindrical surface. Along the circumferential cylinder jacket surfaces, the light sources 34 are arranged.

On a side facing away from the light guide, the coupling-in projection 74 is delimited by a coupling-in reflection surface 78. The Einkoppelreflexionsfläche 78 is insofar the top surface of the cylinder formed Einkoppelvorsprungs 74. The Einkoppelreflexionsfläche 78 is formed so that light entering through the respective light entrance surface 76 is deflected by total internal reflection at the Einkoppelreflexionsfläche to the reflection surface 24 back.

FIG. 12 shows a light guide 10, which extends in the manner of a plate starting from its light exit surface 22. The light exit surface 22 opposite end 50 has two separately extending Lichtleitarme 80. The Lichtleitarme 80 open together in the plate-like portion of the light guide 10, which adjoins the light exit surface 22.

The reflector 26 is divided in this case on the plurality of Lichtleitarme 80. Each of the light guide arms 80 has rear roof edge reflectors 82, which together form the reflector 26.

The Lichtleitarme 80 are preferably each plate-like and extend from different y-axis directions towards the z-axis, which in this case marks the central axis of the light guide 10.

The reflection surface 24 is not designed contiguous in the embodiment according to FIG. Rather, the reflection surface 24 is here in each case embodied as a depression in those boundary surfaces of the light guide arms 80, which merge into the first light guide surface 12 or into the second light guide surface 14.

Opposite these boundary surfaces, the Lichtleitarme 80 facing each other intermediate surfaces 84. The intermediate surfaces 84 converge toward each other in the direction of the light exit surface 22 and connect to one another. The light sources 34 are arranged between the Lichtleitarmen 80. In this case, the light sources 34 are arranged such that the light emanating from them couples in through the intermediate surface 84 into the light guide arm 80 and strikes the depression which is arranged in the opposite boundary surface and serves as a reflection surface 24.

It is conceivable that each light guide arm 80 has a plurality of light sources 34. The light sources 34 are arranged one behind the other in the x-axis direction, for example, and each of the light sources 34 is assigned a depression in the boundary surface of the light guide arm 80.

The embodiments of optical fibers 10 described with reference to FIGS. 10 to 12, to which a plurality of light sources 34 are assigned, are suitable for the stacked arrangement of a plurality of optical fibers 10 which are arranged such that the first optical fiber surface 12 of one of the plurality of optical fibers 10 is adjacent the second light guide surface 14 of the adjacent light guide 10, wherein said light guide surfaces in a transition region 44 near the light exit surface 22 touch.

Claims

Motor vehicle lighting device (38), comprising at least one flat flat-shaped light guide (10) having a first Lichtleitfläche (12), one of the first Lichtleitfläche (12) opposite the second Lichtleitfläche (14), and between an edge (16) of the first Lichtleitfläche (12 ) and an edge (18) of the second light guide surface (14) and the first Lichtleitfläche (12) with the second Lichtleitfläche (14) connecting narrow sides (20), wherein a first region of the narrow sides (20) as a light exit surface (22) and a second region of the narrow sides is designed as a reflector (26), wherein the reflector (26) is adapted to direct a portion of the light emanating from at least one light source (34) and coupled into the light guide (10) in the direction of the light exit surface (22). to steer, characterized in that the illumination device (38) has a plurality of such light guide (10) arranged in a stack so si nd, that the light guide surfaces (12, 14) of adjacent light guides (10) touch at least in a transition region (44), which is at the light exit surface (22) of at least one of the contacting light guides (10), and that of the plurality of light guides (10) whose light exit surface (22) near a lighting device (38) characteristic reference axis (z) is arranged, which serves as a reference direction with H = 0 ° and V = 0 ° for the angles in approval-relevant photometric measurements and when mounted on the vehicle , is arranged to concentrate the light coupled into it so that a light distribution generated by the illumination device (38) has a brightness maximum lying in advance of the illumination device (38).
Motor vehicle lighting device (38) according to claim 1, characterized in that at least one of the plurality of light guides (10) has a reflection surface (24), wherein the reflection surface (24) is a recess in one of the two light guide surfaces (12, 14) extending to extends to a certain depth in the light guide (10) and wherein the at least one light source (34) is arranged so that its light via the recess opposite the light guide surface (14, 12) coupled into the light guide (10) and on the reflection surface ( 24), wherein the reflection surface (24) is adapted to radially reflect incident light and the reflector (26) is adapted to direct light incident thereon either directly to the light exit surface (22) or through further reflection at the reflector (24). 26).
Motor vehicle lighting device (38) according to one of the preceding claims, characterized by imaging optics, in particular an imaging lens (46) which is arranged and arranged to collect light emerging through the light exit surfaces (22) and to direct them to the front of the illumination device (38) and that the light exit surface (22) is arranged in the region of the object-side focal surface of the imaging optics.
Motor vehicle lighting device (38) according to one of the preceding claims, characterized in that the light exit surface (22) of at least one of the plurality of optical fibers (10) is arranged at a distance greater than zero from the object-side focal surface of the imaging lens (46).
Motor vehicle lighting device (38) according to one of the preceding claims, characterized in that at least one of the in the transition region (44) contacting optical fiber (10) is adapted to let propagate in it propagating light so that it with that of an adjacent Optical fiber (10) mixed light emergent.
Motor vehicle lighting device (38) according to one of the preceding claims, characterized in that at least one of the plurality of light guides (10) in subregions of its light exit surface (22) or in the near its light exit surface (22) lying subregions having structures that are suitable, the in to scatter the light guide (10) propagating light.
Motor vehicle lighting device (38) according to one of the preceding claims, characterized in that the light exit surface (22) of at least one of the plurality of light guides (10) below the reference axis (z) of the illumination device (38) is arranged.
Motor vehicle lighting device (38) according to one of the preceding claims, characterized in that between the light exit surfaces (22) and the imaging optics (46), a fixed or a movable aperture (52) is arranged.
Motor vehicle lighting device (38) according to one of the preceding claims, characterized in that the light exit surface (22) of at least one of the plurality of light guides (10) is arranged in the object-side focal surface of the imaging optics.
Motor vehicle lighting device (38) according to one of the preceding claims, characterized in that the light exit surface of at least one of the plurality of optical fibers to the light exit surfaces of the other optical fibers along the optical axis offset or arranged obliquely or has a changed compared to the light exit surfaces of the other optical fiber shape ,
Motor vehicle lighting device (38) according to one of the preceding claims, characterized in that at least one of the plurality of optical fibers (10) the first Lichtleitfläche (12) and / or the second Lichtleitfläche (14) form an angle with the light exit surface (22), the no right angle is.
Motor vehicle lighting device (38) according to any one of the preceding claims, characterized in that the first Lichtleitfläche (12) and the second Lichtleitfläche (14) of at least one of the optical fibers at least over a portion of their longitudinal extent at an angle to each other, which is greater than zero degrees and smaller is 10 degrees, so that the thickness of the plate-shaped light guide (10) changes uniformly toward its exit surface.
Motor vehicle lighting device (38) according to any one of the preceding claims, characterized in that the plurality of optical fibers (10) are arranged inclined to each other, so that a distance between adjacent Lichtleitflächen starting from the transition region (44) towards the light inlet end (50) steadily increases.
Motor vehicle lighting device (38) according to one of the preceding claims, characterized in that a light entry end (50) at least one of the plurality of optical fibers (10) opposite the transition region (44) near the light exit surface (22) by an angle (α) with respect to the reference axis (z ) is angled.
Motor vehicle lighting device (38) according to one of the preceding claims, characterized in that at least one of the plurality of optical fibers (10) in the direction of the reference axis (z) is stepwise formed so that the first Lichtleitfläche (12) and the second Lichtleitfläche (14) with each other at least to form a stage.
Motor vehicle lighting direction (38) according to one of the preceding claims, characterized in that at least one of the stacked optical fibers (10) in its extension along the reference axis (z) is curved.
Motor vehicle lighting device (38) according to any one of the preceding claims, characterized in that at least one of the stacked optical fibers (10) is curved in its extension along a transversely to the reference axis and a normal use axis.
Motor vehicle lighting device (38) according to one of the preceding claims, characterized in that the light sources (34) are controllable separately from one another and / or emit light of different color and / or different intensity.
Motor vehicle lighting device (38) according to one of the preceding claims, characterized in that at least one of the plurality of optical fibers (10) has structures (60, 62, 64, 66, 68, 70, 72) in the form of inner recesses, at which the light in desired directions is directed.
Motor vehicle lighting device (38) according to one of the preceding claims, characterized in that in addition to the light exit surfaces (22) of the stacked light guide (10) further light guide (10) are arranged so that their light exit surfaces (22) at the same height with respect to a reference axis and in the case of an intended use vertically lying axis are the same height as at least one light exit surface (22) of the stacked light guide (10).
Motor vehicle lighting device according to one of the preceding claims, characterized in that at least one of the stacked optical fibers (10) with light of multiple light sources (34) is fed.
Motor vehicle lighting device according to at least one of the preceding claims, characterized in that each optical fiber is supplied with light from at least one light source