DE102007023076B4 - Lighting device for motor vehicles - Google Patents

Abstract

Motor vehicle headlamp with a lighting device comprising at least one light source (12) which couples light via at least one light coupling surface (14) into a rod-shaped light guide (10), the light guide (10) having at least one central light deflection region (22) which is symmetrical in the circumferential direction a plane of symmetry (34) of the light guide (10) is formed and whose main emission direction runs parallel to the plane of symmetry (34), and wherein the light guide (10) has at least one decentralized light deflection area (36) which is not symmetrical in the circumferential direction to the plane of symmetry (34 ) of the light guide (10) is arranged, and wherein the light guide (10) has a light decoupling surface (30) arranged along a longitudinal axis (24) of the light guide (10) and extending symmetrically to the plane of symmetry (34) over part of the circumference and extends at least a portion of the length of the light guide (10), wherein the light deflection areas (22, 36) are provided with decoupling elements (20, 38) arranged next to one another along the longitudinal axis (24) of the light guide (10), which light out in the direction of and to exit through the light outcoupling surface ...

Description

The invention relates to a motor vehicle headlight with a lighting device comprising at least one light source, which couples light via at least one light coupling surface in a rod-shaped light guide. The light guide has at least one central Lichtumlenkbereich which is formed in the circumferential direction symmetrical to a plane of symmetry of the light guide and the main emission direction parallel to the plane of symmetry, at least one decentralized Lichtumlenkbereich which is arranged in the circumferential direction is not symmetrical to the plane of symmetry of the light guide, and one along a Arranged on the longitudinal axis of the light guide light output surface, which extends symmetrically to the plane of symmetry over part of the circumference and at least a portion of the length of the light guide. The light deflection areas are provided with decoupling elements arranged side by side along the longitudinal axis of the light guide, which deflect light in the direction of and to the exit through the light outcoupling surface.

An illumination device of such a motor vehicle headlight is, for example, from the DE 198 03 518 A1 known. Furthermore, rod-shaped light guides are known in the art and, for example in the DE 100 33 133 A1 described. This discloses a rod-shaped light guide, in particular for a signal light for motor vehicles with at least one light output surface and arranged in the direction of a longitudinal axis transversely to the longitudinal axis radiating light exit surface of the light exit surface opposite reflecting surface with light deflecting means which emit light coupled via the light incidence surface on the light exit surface, and with two opposite side surfaces interconnecting the light entry surface and the reflective surface, forming light concentrating points.

Furthermore, from the DE 103 28 216 A1 a rod-shaped light guide is known, wherein on an outer circumference of the light guide at least two offset in the circumferential direction of the light guide staggered areas may be provided with Auskoppelelementen, and wherein the strip-shaped areas may optionally be spaced transversely to the longitudinal extent of the light guide. In this way, a broader radiation characteristic can be achieved.

Furthermore, from the US 2003/0223250 A1 a lighting device with an annularly bent light guide for use as a peripheral frame of a make-up mirror known. The light guide comprises central and decentralized light deflection areas which deflect light in the direction of and exit through the light exit surface. From the EP 1 205 352 A2 is a lighting device with a rod-shaped light guide known. The light guide comprises central and decentralized light deflection areas, which redirect light in the direction from and to the exit through different light exit surfaces and whose main emission directions are at an angle of approximately 90 ° to one another.

In addition, such light guides are often already known in the prior art and are used in particular as an annular arrangement to further light systems in headlights of motor vehicles. In this case, it is advantageous that the light input can be locally separated from the light extraction.

It is disadvantageous in the case of the known, in particular annular, optical waveguides, above all, insofar as they extend over larger areas, that selective shadowing of certain angular ranges can occur through further headlights or lighting elements.

The invention now achieves this object by providing a lighting device of the generic type in which the headlamp next to the illumination device covers or other parts in the headlamp, the Lichtumlenkbereiche are arranged in the light guide, that the main emission of the at least one central Lichtumlenkbereichs and the main emission of the at least one decentralized light deflection region enclose an angle of 10 ° to 30 ° between them, and that the at least one decentralized light deflection region deflects light in the direction of and exiting through the light outcoupling surface in such a way that it passes by the diaphragms or the other parts of the headlight ,

Symmetrically this should also be understood as largely symmetrical arrangements. This is achieved by the light distribution is not formed symmetrically by the Lichtumlenkbereich, but a cross-over beam path is created so that no symmetrical beam path is formed in front of the light output surface, but a light emission, for example, mainly on one or the other side of the plane of symmetry is generated. In this way, the problem that can occur especially in a daytime running light, especially in unfavorable installation situations in a symmetrically radiating structure by screens or other parts in the headlight are shaded, such as by tubes, etc., can be reduced. By the provided crossing beam path, which is realized by the decentralized Lichtumlenkbereich, this can Shadowing effects are reduced. The term "in the circumferential direction" denotes an arrangement of the light deflection or light output surface on the lateral surface or the longitudinally extending outer wall of the light guide, which need not be cylindrically shaped. Thus, in addition to the extent in the longitudinal direction of the light guide, the light deflection areas and the light output surface also have an extension transversely thereto, this direction being designated as a circumferential direction.

It may be provided on the one hand, that only a decentralized Lichtumlenkbereich is provided, which extends over the entire length or only a portion of the length of the rod-shaped light guide. The rod-shaped light guide can be designed so that it is straight or curved or bent. In particular, it can also be provided that the rod-shaped light guide has at least one branch and splits, for example, into two arms, which in turn can be connected together to form an annular light guide, wherein it can be provided in particular that the annular region of the rod-shaped light guide in the can be arranged for a viewer visible part of a lighting device, whereas the area before splitting the light guide can be arranged in two arms so that it is not visible to a viewer of a corresponding lighting device, but that in this area is the light coupling surface.

It is envisaged that the optical waveguide has a plurality of light deflecting regions, wherein light deflecting regions can be formed as central light deflecting regions symmetrical to the plane of symmetry or as further decentralized light deflecting regions not symmetrical to the plane of symmetry of the optical waveguide. The light emission of all Lichtumlenkbereiche takes place in such a way that the light emission takes place through the symmetrical light output surface.

For this purpose, it can be provided that the different light deflection areas, in particular a central and a decentralized light deflection area, extend over a same section of the length of the light guide. However, it can also be provided that the extent is formed differently in the longitudinal direction of the light guide. So z. B. be provided that in an annular light guide in the installed position only in two lateral areas of the annular light guide decentralized Lichtumlenkbereiche are provided, whereas only the central Lichtumlenkbereichs is provided in the upper and lower ring area. The design, on which sections and over which length decentralized or central light deflection areas are provided, can be made dependent on the individual shading conditions. For this purpose, it may be significant whether only areas or the entire rod-shaped light guide is subject to shading, and in addition, the required light characteristics that are to be achieved by the lighting device or must be achieved due to legal requirements, may be crucial.

In particular, provision may be made, provided that there is a central and decentral deflection region, that the central light deflection region is narrower in the circumferential direction than is customary in the prior art. In this way, in particular space for a further Lichtumlenkbereich the side thereof, that is not symmetrical to the plane of symmetry of the light guide created.

It can be provided that the at least one decentralized light deflection region and the central light deflection region are connected to one another. D. h., The two Lichtumlenkbereiche abut in the cross section of the light guide directly to each other. The transition between the Lichtumlenkbereichen can be both continuous and unsteady. In this case, transitions through edges or steps come into question, and transitions that can be realized by a curve can also be given. In principle, it can also be provided that the two light deflection areas are spaced apart in the circumferential direction. The spacing is here set by the size ratios and the necessary width of the proposed decoupling limits.

It is particularly advantageous if a main light emission direction of the central light deflection region and a main light emission of a decentralized light deflection region enclose an angle of 10 ° to 30 ° between them, wherein the light main emission direction of the central light deflection region coincides with the plane of symmetry. The main light emission direction of the central region thus corresponds to the main light emission direction of the light guide as such. By tilting the Hauptabstrahlrichtungen the central and the decentralized Lichtumlenkbereiche the decentralized Lichtumlenkbereich can radiate defined in angular ranges, which do not coincide with the actual main emission of the light guide. Thus, it can be achieved in this way that light which would normally be emitted in the region of shading, for example by a tube or further diaphragm elements of a motor vehicle headlight, and thus to generate a light distribution in front of the illumination device on a road in front of a motor vehicle no longer would be available, is emitted by the decentralized Lichtumlenkbereich so that a cross-over beam path is provided and As additional light exits through the light output surface and is available for generating a light distribution, for example in front of a motor vehicle.

Depending on the desired arrangement, the main emission direction of the decentralized light deflection region can be provided such that it is provided on one side or on the other side of the plane of symmetry of the light conductor. In principle, more than two or three light deflection regions can be provided in the circumferential direction, but also in the longitudinal direction next to each other.

The Lichtumlenkbereiche have for coupling to light so-called decoupling elements which are arranged transversely to the longitudinal axis of the light guide and are preferably formed by prisms, wherein the prisms are designed in particular symmetrical. It can be provided that the individual Lichtauskoppelelemente connect directly to each other in the longitudinal direction of the light guide. However, it may also be provided distances between the light output elements or it can be provided lichtauskoppelelementfreie areas. In this case, the Auskoppelelementbreite and their position and the optical fiber cross-section provide for the light distribution of the decoupled light.

In addition, it can be provided, in particular, that an end face of the light guide serves as a light coupling surface.

In this case, in particular the light coupling can be provided away from the light extraction, for which purpose, in particular, intermediate regions in the longitudinal direction of the light guide can be provided which do not carry a light deflection region and have no light coupling-out surface. In this area of the light guide, which can be referred to as light transmission area, the light is deflected by total reflection, without leaving the light guide. Only when the light strikes a light deflection region with outcoupling elements, which deflects the light in such a way that it is no longer reflected by total reflection on the lateral surface of the light guide in the region of the light outcoupling surface can light escape through the light coupling-out surface.

If it is provided that, for example, to form an annular illumination device, the light guide is split into two arms, which then recombine into a ring shape, the splitting region can be designed so that the lowest possible losses occur in this area. This can be done for example by choosing a particular angle of the two arms to each other, as for example in the DE 101 62 105 A1 is described. Alternatively, however, deflection devices, for example in the form of a prism inserted there, can also be provided in the splitting region, which deflect the light by reflection so that it enters the two arms of the light guide and is forwarded there by total reflection.

Furthermore, more than one light entry surface can be provided. In particular, in the case of a rod-shaped light guide, both end faces may also be formed as a light entry surface.

A corresponding light guide can serve as a lighting device, whereby in particular a daytime running light can be formed, which complies with the regulations for daytime running lights in accordance with the respective applicable statutory provisions.

Further advantages and features of the invention will become apparent from the remaining application documents. The invention will be explained in more detail below with reference to a drawing. Showing:

1 a schematic representation of a rod-shaped light guide according to the prior art;

2 a lighting device according to the prior art;

3 a lighting device according to the invention and

4 in the representations a), b) and c) three embodiments of a light guide according to the invention.

1 shows a light guide, in its entirety by the reference numeral 10 is designated and rod-shaped. In this case, the side view of such a light guide is shown in representation a), whereas illustration b) of FIG 1 shows a light guide in section along the line AA.

Furthermore, it is a light source 12 provided the light via a light coupling surface 14 at one end of the light guide 10 is arranged in the light guide 10 couples. The light is here, as by the light beam 16 is clarified by means of total reflection in the lateral surface 18 of the light guide 18 deflected it to a decoupling element 20 impinges on a Lichtumlenkfläche 22 , which extends in the longitudinal direction of the light guide and is provided over a peripheral region of the light guide in the transverse direction, is arranged. The decoupling elements 20 are here symmetrical prisms, which are transverse to the longitudinal direction, by the arrow 24 is indicated, are arranged. Meet the rays of light, like the ray of light 16 then in its further course, on such a light output element 20 . they are deflected in such a way that they leave the optical fiber without passing through the lateral surface 18 the light guide to be reflected again. Here, the light guide 10 a longitudinally extending, over a peripheral region of the light guide 10 extending area on, as a decoupling surface 26 serves.

In this case, the rod-shaped light guide in particular a plane of symmetry, with the reference numeral 34 wherein the two lying beyond the plane of symmetry halves of the light guide 10 are constructed mirror-symmetrically. The main light emission direction of the light guide coincides with the plane of symmetry 34 together.

To achieve the most uniform possible light distribution on both sides of the plane of symmetry, it is provided in the prior art, the Lichtumlenkfläche also symmetrical to the plane of symmetry 34 form and in particular the decoupling elements 20 symmetrical to the plane of symmetry 34 to design.

In representation b) of 1 is the light guide 10 now shown in cross-section along the line AA, wherein the light guide 10 a light guide body 28 essentially comprising a first subarea 28a exists, which has an ellipsoidal base, and a partial area 28b which has a trapezoidal base. The two subareas, where the subarea 28a In particular, only one part of the ellipse can be connected to each other in one piece and without an interface. In the area of the part 28b is by the one parallel surface of the trapezoid the Lichtumlenkfläche 22 formed on the light output elements 20 are arranged. It shows 1 an embodiment according to the prior art. Furthermore, in 1b with a curved bracket and the reference numeral 30 the light output surface of the light guide 10 , which extends over a part of the circumference of the light guide, characterized.

2 shows an embodiment of a lighting device according to the prior art, in which case the rod-shaped light guide 10 a first light guide area 10a having, as a Lichtdurchleitbereich for an annular waveguide region 10b serves, with the light guide 10 at the transition from the fiber optic area 10a in the area 10b divided into two arms, which then in turn to form the annular area 10b connected to each other in one piece and without an interface. Furthermore, here is a light source 12 shown. In the area of the annular section 10b of the light guide 10 is now a light deflection area 22 characterized by a thick line that the Lichtumlenkbereich 22 according to 1 equivalent. In light deflection area 22 are decoupling elements 20 arranged in the form of symmetrical prisms. The prisms hereby have a width B, which in 1b is indicated. With the reference number 32 is a tube characterized in the built-spotlight on all sides around the annular area 10b extends the light guide and this includes. A corresponding light guide can serve as a lighting device, whereby in particular a daytime running light can be formed, which complies with the regulations for daytime running lights in accordance with the respective applicable statutory provisions.

Here, the representation marked with a) in 2 a view from the front, whereas representation b) shows a section along the line BB.

In illustration b), the light emission of the light guide is now shown with a single light deflection surface, which is designed as a centric light deflection surface.

Due to the comparatively wide design of the decoupling elements as broad as possible radiation of the light is achieved in front of the light output surface, wherein the light at a certain angle, for example, 20 ° to the main emission, with the plane of symmetry 34 coincides, is radiated around. Through the tube 32 However, the light emerging at an angle of 20 ° is shaded and thus lost for a light distribution.

3 shows an embodiment according to the invention, wherein the decoupling elements 20 here have a smaller width b than the decoupling elements 20 according to 1 and 2 , Instead of the broad decoupling elements 20 in the light deflection area 22 Here are partially at the two lateral regions of the annular portion of the light guide 10b further light deflection surfaces 36a and 36b intended. These do not extend over the entire circumference of the annular portion 10b like the light deflection area 22 does. In the light deflection areas 36a and 36b are also Lichtauskoppelelemente 20 according to the light deflection area 22 intended. As well as in 2 in illustration a) is now the tube 32 However, in a built-in lighting device, the light guide 10 in its annular section 10b would completely enclose.

3 shows in representation b) a section through the tube and the light guide 10 according to 3a , Due to the narrower Auskoppelelementreihen here on the one hand by the central Lichtumlenkbereich another light distribution is generated so that the beam path has a low or no light component which is emitted at an angle such that it shading by the tube 32 would be subject. On the other hand, the corresponding light guide ring 10b now an asymmetrical emission due to the decentralized, ie arranged outside the plane of symmetry deflection 36a and 36b that too 4 yet to be described. Due to the narrower decoupling elements in the circumferential direction, these have a narrower angular spread and by means of the Lichtumlenkbereiche 36a and 36b can be generated in certain areas crossing beams for a larger angular range, but which can be specified in terms of its emission such that no shading occurs and yet there is a greater horizontal dispersion of the light distribution in front of such a lighting device.

4 shows three embodiments of a light guide according to the invention, each with a central Lichtumlenkbereich 22 and a decentralized light deflection area 36 , The central light deflection area 22 corresponds to the in 1 shown, but has a smaller width, which is designated here by b, as the Lichtumlenkbereich 22 in 1 that has a width B with respect to its decoupling elements 20 having. In addition, one of them is circumferentially spaced decentralized light deflection area 36 provided, which is not symmetrical to the plane of symmetry 34 is arranged. With 40 designated light rays come from a deflection by the light output elements 20 of the light deflection area 22 , which is symmetrical to the symmetry plane 34 is trained. These light extraction elements couple mainly into the area HV on a measuring screen which would be arranged in front of a corresponding illumination device. In addition, light is emitted through the decoupling elements 38 the decentralized deflection area 36 decoupled, these rays of light with 42 are designated and at an angle of about 20 °, which is denoted by α, to the Hauptlichtabstrahlrichtung, with the plane of symmetry 34 coincides, the Lichtumlenkbereichs 22 are tilted. D. h., The main emission of the deflection 36 lies at an angle of 20 ° to the main light emission of the Lichtumlenkbereichs 22 that is the direction of the plane of symmetry 34 equivalent.

A further deflection of the light rays is thereby acting through the lateral surface acting as a lens 18 generated by the light guide.

Representation b) now shows a further design, whereby here too a decentralized light deflection surface 36 and a central Lichtumlenkfläche 22 are provided. As shown 4b are the light deflection areas 22 and 36 formed immediately adjacent to each other, wherein in the transition an edge 44 is provided. Alternatively, as in 4c is provided, a continuous transition by means of a curve (spline) are created between the Lichtumlenkbereich 36 and the light deflection area 22 , with the transition here with 46 is marked.

Due to the additional light deflection area 36 , which is arranged decentralized and Lichtauskoppelelemente 38 can also be emitted in angular ranges that do not match the original main emission. Was according to 2 the angular range of 20 ° blocked by the tube to the tube side, can by an additional Lichtumlenkbereich 36a , b outside the light deflection area 22 , as in 3 shown, a radiation in this solid angle can be avoided, the area 36a and the area 36b each toward the interior of the annular portion 10b radiate. In this way, light rays that would be shaded by laterally adjacent apertures or headlamp parts, and thus block light that could be provided for generating a light distribution, for example in front of a motor vehicle, can now be bypassed by no longer operating certain angular ranges of the illumination device.

Claims (7)

Motor vehicle headlight with a lighting device comprising at least one light source ( 12 ), the light via at least one light input surface ( 14 ) in a rod-shaped light guide ( 10 ), wherein the optical fiber ( 10 ) at least one central light deflection area ( 22 ) which is symmetrical in the circumferential direction to a plane of symmetry ( 34 ) of the light guide ( 10 ) and whose main emission direction is parallel to the plane of symmetry ( 34 ), and wherein the optical fiber ( 10 ) at least one decentralized light deflection area ( 36 ) which is not symmetrical in the circumferential direction to the plane of symmetry ( 34 ) of the light guide ( 10 ), and wherein the optical fiber ( 10 ) one along a longitudinal axis ( 24 ) of the light guide ( 10 ) arranged light output surface ( 30 ) symmetrically to the plane of symmetry ( 34 ) over a part of the circumference and at least a portion of the length of the light guide ( 10 ), wherein the light deflection areas ( 22 . 36 ) along the longitudinal axis ( 24 ) of the light guide ( 10 ) juxtaposed decoupling elements ( 20 . 38 ), the light in the direction of and to exit through the light output surface ( 30 ), characterized in that the headlamp in addition to the illumination device covers or other parts in the headlight that the Lichtumlenkbereiche ( 22 . 36 ) in the optical fiber ( 10 ) are arranged so that the main emission direction of the at least one central Lichtumlenkbereichs ( 22 ) and the main radiation direction of the at least one decentralized Light deflection area ( 36 ) enclose between them an angle of 10 ° to 30 ° and that the at least one decentralized light deflection zone ( 36 ) Light in the direction of and to exit through the light output surface ( 30 ) deflects so that it passes the panels or the other parts of the headlamp. Motor vehicle headlight according to claim 1, characterized in that the Lichtumlenkbereiche ( 22 . 36 ) over different long sections of the length of the optical fiber ( 10 ). Motor vehicle headlight according to claim 1 or 2, characterized in that the at least one decentralized light deflection region ( 36 ) and the at least one central light deflection region ( 22 ) discontinuously or continuously merge into each other or are spaced from each other. Motor vehicle headlight according to one of the preceding claims, characterized in that the decoupling elements ( 20 . 38 ) transverse to the longitudinal axis ( 24 ) of the light guide ( 10 ) are arranged prisms. Motor vehicle headlight according to claim 4, characterized in that the prisms are symmetrical. Motor vehicle headlight according to one of the preceding claims, characterized in that an end face of the light guide ( 10 ) as light input surface ( 14 ) serves. Motor vehicle headlight according to one of the preceding claims, characterized in that the illumination device is designed as a daytime running light, according to the legal provisions, as a flashing light, marker light, taillight, fog light, brake light.

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