DE102017119475A1 - optical fiber - Google Patents

Abstract

A light guide (2) is proposed for an illumination device of a motor vehicle having a light coupling region (4) and a first light guide section (6), wherein the first light guide section (6) adjoins the light coupling section (4), wherein a second light guide section (12) protrudes from a longitudinal side (14) of the first Lichtleitabschnitts (6), and wherein a transition region (10) between the first Lichtleitabschnitt (6) and the second Lichtleitabschnitt (12) in the direction of Lichteinkoppelbereichs (4) comprises a cross-section decrease.

Description

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

Optical fibers which have a first light guide section which adjoins a light coupling section are well known.

Furthermore, it is known that the most homogeneous bright appearance of a light-emitting surface for certain lighting functions such as daytime running lights or indicators are desired for design reasons. Thus, it is an object of the invention to provide an easy to manufacture light guide, which allows this homogeneous appearance of the radiating surface with low space consumption.

The object underlying the invention is achieved by a light guide according to claim 1.

It is proposed that a second light guide section projects from a longitudinal side of the first light guide section, and that a transition area between the first light guide section and the second light guide section in the direction of the light coupling area comprises a cross-sectional decrease. A luminous flux in the first light guide section decreases through the coupling along the transition area into the second light guide section. This coupling or this passage of the luminous flux from the first Lichtleitabschnitt into the second Lichtleitabschnitt can be adjusted by the proposed reduction in cross section so that a very constant luminous flux per length section from the first Lichtleitabschnitt can pass into the second Lichtleitabschnitt. This type of coupling into the second light guide section lays the foundation for a homogeneous appearance in light extraction from the second light guide section.

In an advantageous embodiment, the second light-guiding section protrudes flat and in one piece from the first light-guiding section. In this way, an overall flat light guide can be created, which can be developed on the other with little effort. In addition to the resulting reduced development costs, the complexity in the production is reduced, especially when using an injection molding process. Thus, there are several cost advantages.

In a further advantageous embodiment, the second light guide section comprises a number of branches, which protrude from the first light guide section, wherein the transition area is divided into a number of the transfer sections associated with the branches. The number of branches gives degrees of freedom in light conduction and light extraction.

In an advantageous embodiment, the crossing region comprises a groove that recedes in the direction of the light coupling-in section. Advantageously, in this way, degrees of freedom result in the design of the second light-conducting section. For example, the second light-guiding section can be connected to the groove of the transition area with a constant thickness.

In an advantageous embodiment of the light guide, the crossing region comprises the second light guide section, which tapers in the direction of the light coupling section. By the taper of the second Lichtleitabschnitts in the direction of Lichteinkoppelabschnitts the cross-sectional decrease of the Übertrittsbereichs is realized. The taper thus implies a thickening towards the end of the first light guide section and ensures that a greater proportion of the light present in a lesser amount towards the end of the first light guide section can pass into the second light guide section ,

In a further advantageous embodiment, a light guide surface of the first light guide section, which is assigned in particular to the longitudinal side of the first light guide section, has a cross-sectional increase corresponding to the cross-sectional decrease in the direction of the light coupling zone. Advantageously, a larger or larger reflection surface is provided by the proposed light guide to Lichteinkoppelbereich out to direct the light flux from the Lichteinkoppelbereich away. By contrast, a smaller or decreasing reflection surface is provided by the light input region.

A further advantageous embodiment is characterized in that a Convex curvature of the Lichteinkoppelbereich facing away from the narrow side of the second Lichtleitabschnitts spans a first plane which is substantially parallel to or equal to a second plane, which is spanned by a curvature of the first Lichtleitabschnitts. Thus, the curvature of the narrow side corresponds to the curvature of the first Lichtleitabschnitts such that homogeneous and parallelized light beams from the first Lichtleitabschnitt into the second Lichtleitabschnitt. The curvature of the narrow side can thus contribute to a light extraction, which produces a homogeneous appearance.

A further advantageous embodiment of the light guide is characterized in that the convex curvature of the narrow side of the second light guide section facing away from the light coupling section corresponds to the curvature of the first light guide section, so that a light bundle with substantially parallel light beams is emitted by the light coupling-out area. This contributes to the production of a homogeneous appearance of the emission light distribution.

An advantageous embodiment of the optical waveguide is characterized in that the narrow side of the second optical waveguide section facing away from the light coupling region comprises a light outcoupling surface for coupling out the light.

An alternative advantageous embodiment of the light guide is characterized in that the narrow side of the second Lichtleitabschnitts includes a deflection, which is inclined relative to a light outcoupling surface of the second Lichtleitabschnitts, the Lichtleitfläche the second Lichtleitabschnitts, which includes an acute angle with the deflection, the light outcoupling surface ,

A further advantageous embodiment of the optical waveguide is characterized in that the second optical waveguide section comprises one or more light outcoupling surfaces, each extending or extending substantially equidistant from the narrow side.

A further advantageous embodiment of the light guide is characterized in that the first Lichtleitabschnitt so adjoins the Lichteinkoppelbereich that a parallel aligned and homogeneous light bundle has a direction when entering the Lichtleitabschnitt, which the light beam at the first impingement on one of the light guide surfaces of the first Lichtleitabschnitts there with an angle to the solder incident on the light guide surface, which is greater than the critical angle of total internal reflection.

In an advantageous development of the light guide, a first deflection surface of the coupling region is adapted to direct light emanating from a point located outside the light guide in front of a light entry surface on a second deflection surface, wherein the first deflection and the second deflection by their respective shape and Are arranged to cooperate so that the light emanating from the point after the reflection at the first deflection surface and the second deflection surface forms the parallel aligned and homogeneous light beam.

Another aspect of the invention relates to a lighting device for a motor vehicle, which comprises the proposed light guide and a light source associated with the light source.

• 1 eine schematische Seitenansicht eines Lichtleiters;
• 2 und 3 einen jeweiligen Querschnitt aus 1;
• 4 eine perspektivische Ansicht des Lichtleiters aus 1;
• 5 und 6 alternative Ausführungsformen zu den Querschnitten aus 1;
• 7 einen Längsschnitt durch einen schematisch dargestellten weiteren Lichtleiter;
• 8 in einer perspektivischen schematischen Ansicht eine weitere Ausführungsform des Lichtleiters;
• 9 in schematischer perspektivischer Ansicht eine Weiterbildung des Lichtleiters aus 8;
• 10 in schematischer perspektivischer Ansicht einen Teil des Lichtleiters aus 9;
• 11 die Lichtauskopplung aus dem Lichtleiter gemäß den 9 und 10;
• 12 in einer schematischen perspektivischen Ansicht eine Ausführungsform eines Lichteinkoppelbereichs des Lichtleiters; und
• 13 einen schematisch dargestellten Lichteinkoppelbereich.

Further embodiments, advantages and possible applications of the invention can be found in the following description of exemplary embodiments, which are illustrated in the figures of the drawing. For functionally equivalent sizes and features, the same reference numerals are used in the drawing even in different embodiments. In the drawing show:

• 1 a schematic side view of a light guide;
• 2 and 3 a respective cross section 1 ;
• 4 a perspective view of the light guide 1 ;
• 5 and 6 alternative embodiments to the cross sections 1 ;
• 7 a longitudinal section through a schematically illustrated further optical fiber;
• 8th in a perspective schematic view of another embodiment of the light guide;
• 9 in a schematic perspective view of a development of the light guide 8th ;
• 10 in a schematic perspective view of a part of the light guide 9 ;
• 11 the light extraction from the light guide according to 9 and 10 ;
• 12 in a schematic perspective view of an embodiment of a Lichteinkoppelbereichs of the light guide; and
• 13 a schematically illustrated Lichteinkoppelbereich.

1 shows a schematic side view of a light guide 2 for a lighting device of a motor vehicle. The light guide 2 has a Lichteinkoppelbereich 4 on. To the following 13 explained in detail Lichteinkoppelbereich 4 closes a present curved first Lichtleitabschnitt 6 at. The light guide section 6 has a rectangular longitudinal cross-section. The first light guide section 6 Of course, it can also be designed with little or no curvature. One in the first light guide section 6 coupled luminous flux propagates under total reflection with a medium propagation direction 8th in the first light guide section 6 out. The first light guide section 6 goes in a crossing area 10 in a second light guide section 12 above. The second light guide section 12 is essentially flat and protrudes from a convex longitudinal side 14 the first Lichtleitabschnitts 6 from.

The first light guide section 6 closes in such a way to the Lichteinkoppelbereich 4 on, so that a parallel aligned and homogeneous light beam on entering the first Lichtleitabschnitt 6 has a direction which the light beam at the first impact on a light guide surface 16 or 18 the second Lichtleitabschnitts 12 there with an angle to the solder on the respective light guide surface 16 or 18 which is greater than the critical angle of total internal reflection. Despite the curvature of the first Lichtleitabschnitts the order of the light rays remains up to the slight light vibrations up to the Lichteinkoppelbereich 4 opposite end 20 the first Lichtleitabschnitts 6 receive.

The second light guide section 12 includes a first the Lichteinkoppelabschnitt 4 opposite narrow side 22 and a second one of the light guide section 4 facing narrow side 24 , The first narrow side 22 is convexly curved, with the curvature of the narrow side 22 and the curvature of the first light guide section 6 , in particular the curvature of the light guide surface 16 , correspond, so that a light beam with substantially parallel light beams from a Lichtauskoppelbereich 26 is emitted. The curvature of the first Lichtleitabschnitts 6 ensures that, as by rays of light 28A to 28E shown in the second Lichtleitabschnitt 12 initially spread lightly diverging light rays. By refraction on the convexly curved first narrow side 22 the emitted light becomes according to a common main emission direction 30 parallelized by the light guide 2 radiated.

The light beams propagate in the first light guide section 6 by a number of reflections, wherein the light rays are substantially always, that is, at each reflection at substantially the same angle to the light guide surfaces of the first Lichtleitabschnitts 6 meet and there each subject to total reflection. In the area of the crossing area 10 goes the first light guide section 6 in the second light guide section 12 over, which instead of a total reflection, a passage of the light rays in the second Lichtleitabschnitt 12 he follows. The transition area 10 which is between the first light guide section 6 and the second light guide section 10 lies, points in the direction of Lichteinkoppelbereichs 4 a cross-section decrease. This will be followed by the 2 and 3 explained in more detail.

2 shows a first cross section AA 1 of the light guide 2 , wherein the cross section AA in the direction of the Lichteinkoppelabschnitts 4 is arranged.

3 shows a second cross section BB 1 of the light guide 2 , wherein the cross section BB in the direction of the end 20 the first Lichtleitabschnitts 6 is arranged. From the cross sections AA and BB is readily apparent that the cross section of the transition region 10 between the first light guide section 6 and the second light guide section 12 in the direction of the end 20 elevated. In the present case, this cross-sectional increase is towards the end 20 realized in that the entire cross section of the first Lichtleitabschnitt 6 subsequent second Lichtleitabschnitts 12 at least in the area of the crossing area 10 increased.

The crossing area 10 includes light guide surfaces 16 and 17 that come to an end 20 the first Lichtleitabschnitts 6 rejuvenate. The light guide surfaces 16 and 17 serve together with the opposite light guide surface 32 for reflection in the first Lichtleitabschnitt 6 propagated light rays and thus the transport of a luminous flux within the first Lichtleitabschnitts 6 in the direction of propagation 8th , A first cross section 34 the crossing area 10 increases in the course of the first Lichtleitabschnitts 6 towards the end 20 except for a second cross-section 36 of sections B - B and beyond.

Starting from the section BB to the section AA reduces the cross-section of the material of the light guide 2 for example, on a m-tel. The fact that only one mth of the light in the region of the section A - A in the second Lichtleitabschnitt 12 is coupled, remains after the section A - A only a portion of k = (m-1) / m of the light in the first Lichtleitabschnitt 6 , This remaining portion of the light can be in (m-1) other crossing areas 10 in the second light guide section 12 transgressed. To these crossing areas 10 may be a common, flat trained Lichtleitabschnitt 12 connect or the second Lichtleitabschnitt 12 includes a number of separate branches. Between sections AA and BB, there is preferably a monotonic increase in the cross section 34 on the cross section 36 , As a result of this monotonous increase in the cross section, the luminous flux decreases over the length of the first light-conducting section 6 due to absorption and by passage of light into the second light guide section 12 continuously off.

4 shows a perspective view of the light guide 2 out 1 , The second light guide section 12 protrudes flat and in one piece from the first Lichtleitabschnitt 6 from. The convex curvature of the Lichteinkoppelbereich 4 opposite narrow side 22 biases a first plane which is substantially parallel to or equal to a second plane which is spanned by a curvature of the first light guide section. Preferably passes through the second Lichtleitabschnitt 12 a third plane parallel to the first and second planes or equal to the first and / or second planes is. The curvatures of the first Lichtleitabschnitts 6 and the narrow side 22 For example, lines correspond along edges or planes of said elements. By the proposed alignment of the curvatures to each other, it is possible, although diverging but substantially homogeneous and parallelized light beam from the second Lichtleitabschnitt 12 such that a homogeneously bright exit surface for the out of the light guide 2 decoupled light arises. The narrow side 22 includes the light output surface 38 , The light output surface 38 the narrow side 22 and at least one of the light guide surfaces 16 and 18 the first Lichtleitabschnitts 6 are aligned perpendicular to a common level.

5 and 6 show alternative embodiments to the sections AA and BB 1 , The light guide surface 17 lingers in the course of the first Lichtleitabschnitts 6 at the same size. As shown in section AA, the crossing area points 10 a groove 40 on, which in the course of the first Lichtleitabschnitts 6 towards its end 20 disappears and / or their depth is reduced. Corresponding to that in the course of the end 20 towards decreasing depth of the groove 40 following the Lichtleitfläche decreases 16 ,

7 shows a section through a schematically illustrated further light guide 2 , The light coupling area 4 has a light input surface 42 , a first deflection surface 44 and a second deflection surface 46 on. The first deflection surface 44 is designed to receive light from an outside of the light guide 4 in front of the light coupling surface 42 lying point 48 emanating a light source, so deflect, that the deflected light, the second slightly curved deflection almost homogeneously illuminated. The luminous means preferably comprises at least one semiconductor light source. The second deflection surface 46 is in the light path behind the first deflection surface 44 arranged. Their shape and position is determined by the requirements that from the first deflection 44 forth incident light from the second deflection 46 as a parallel aligned and homogeneous light beam 50 is reflected. The first light guide section 6 closes at the Lichteinkoppelbereich 4 on that the parallel aligned light beam 50 upon entry into the first Lichtleitabschnitt 60 has a direction that it when first hit the light guide surface 16 there with an angle of 45 ° to 75 °, for example, an angle of 60 °, to the solder on the Lichtleitfläche 16 meets.

A light-emitting diode used as a light source is arranged so that the center of their light entrance surface 42 directed light exit surface in the center of the spherical shape of the light entry surface 42 of the light guide 2 lies. This spherical form appears in the section shown as a circular shape.

After by reflections on the first deflection 44 and the second deflection surface 46 After conversion of the coupled light beam, the light propagates through repeated total reflection along the first light guide section 6 out.

The effects of cooperating first deflection 44 and the second deflection surface 46 are the following: After the reflection at the second deflection 46 the rays go 50 parallel to each other, and the two rays each have the same distance to their neighboring beams after double reflection, are thus equidistant. The between the first deflection 44 and the second deflection surface 46 running rays are not yet parallel to each other. The from the second deflection 46 outgoing rays 50 meet at the angle of 45 ° to 75 °, for example, an angle of 60 ° to the normal to the actual light guide surface 16 the first Lichtleitabschnitts 6 , After reflection at the light guide surface 16 become the rays at the light guide surface 32 reflected to by means of the crossover area 10 into a branch 52 the second Lichtleitabschnitts 12 convert. The branch 52 closes with a perpendicular to the rays 50 arranged light output surface 54 down, causing the rays 50 without refraction angle from the light guide 2 escape.

In not shown form, the optical fiber of the 7 more branches 52 which, starting from the branch shown 52 in the direction of propagation 8th to the first light guide section 6 are formed. For this purpose, the optical fiber shown 2 the previously described training the Übungsbereich 10 with a number of crossing sections.

8th shows in a perspective schematic view of another embodiment of the light guide 2 , The narrow side 22 has a deflection surface instead of a light exit surface 56 on, which redirects the incident light and a light output surface 58 which part of a light guide surface 60 the second Lichtleitabschnitts 12 is, decoupled. The deflection surface 56 is opposite the light output surface 60 inclined and closes with the decoupling surface 60 an acute angle. Due to the corresponding curvatures of the narrow side 22 and the light guide section 6 remains a homogeneous appearance of the through and by the light output surface 58 obtained from decoupled light. Due to the position of the decoupling surface 60 and the deflection surface to each other can determine an exit direction. This light extraction is based on light rays 62 A to 62 G illustrated.

By choosing the orientation of the deflection 56 and by choosing the course of the narrow side 22 is it possible the main radiation direction 76 to influence. Consequently, the deflection must 56 and the curvature of the narrow side 22 correspond in such a way that the emission of light in the particular main emission direction 76 is reached. If additionally parallel light should emerge, then the curvature of the narrow side must 22 on the curvature of the first Lichtleitabschnitts 6 be coordinated.

9 shows a schematic perspective view of a development of the light guide 2 out 8th , In addition to the provision of a deflection 56 on the narrow side 22 are not shown equidistant to the narrow side 22 extending decoupling provided which a light extraction via a relative to the 8th enlarged light output surface 58 allows. Based on the light rays 64A to 64G , which are divided into partial light beams in the region of the decoupling elements, this type of light decoupling is illustrated.

10 shows a schematic perspective view of a part of the light guide 2 out 9 , The deflection surface 56 closes with the light guide surface 60 an acute angle. Equidistant to the narrow side 22 run notches 66 and 68 with respective deflection surfaces 70 and 72 , The deflection surfaces 70 and 72 as well as the deflection surface 56 each perpendicular to a common plane to a light extraction via the light output surface 58 to reach, wherein the light beams are radiated in the same main emission direction. The scores 66 and 68 may alternatively have different notch depths.

11 illustrates the light extraction from the light guide 2 according to the 9 and 10 , The light beam 74 is from the deflection 70 deflected and passes under refraction from the light guide 2 in a main propagation direction 76 out. The light beam 78 however, it hits the one in the beam path after the notch 66 arranged deflecting surface 56 which the beam 78 diverted. The beam 78 passes under refraction from the light guide 2 with the main emission direction 76 out.

12 shows a schematic perspective view of an embodiment of the Lichteinkoppelbereichs 4 of the light guide 2 , There are schematically three bulbs 80A . 80B and 80C shown, each of the bulbs 80A to 80C a spherical light input surface 42A to 42C assigned. Advantageously, thus a brighter irradiation of the light guide 2 be achieved. By using light sources 80A-C different light color can be different functions such as flashing light with yellow LEDs and daytime running lights with white LEDs are generated. In addition, it is possible the cross section of the crossing area 10 to vary more, whereby the homogeneity of the radiation of the second light guide section 12 is improved. Of course, differently constructed Lichteinkoppelbereiche are conceivable according to the order described, the light beam 50 in the first light guide section 12 couple.

The light rays shown in this description are basically to be interpreted as a ray bundle, which starting from a point light source. When used in a spotlight, these rays must exit the light guide 2 pointing in the direction of the direction of travel. When using the light guide 2 In a rear light, on the other hand, you have to beam against the direction of travel of the light guide 2 radiate. Of course, a rotation of the light guide 2 around the main radiation direction possible to perform an adaptation to space and / or to meet design specifications.

Of course it is possible that of the light guide 2 To adapt radiated light distribution by facets to legal requirements. These facets can be in the range of a respective light output surface of the light guide 2 be provided.

13 shows the schematically illustrated Lichteinkoppelbereich 4 in a reduced to the shape and arrangement of its reflective surfaces in a longitudinal section shape. The description too 13 is to all previously described embodiments of the light guide 2 applicable. In detail, the shows 13 the light guide 2 that the light coupling area 4 and the first light guide section 6 having. The light coupling area 4 has the light input surface 42 and the deflection surface 44 on. In addition, the light coupling area points 4 a second deflection surface 46 on. The first deflection surface 44 is set to light 90 that from one outside the light guide 2 in front of the light entry surface 42 lying point 48 of a luminous means, to redirect so that the deflected light, the slightly curved second deflection surface 46 almost homogeneously illuminated.

How out 13 it can be seen, is the second deflection 46 in the light path behind the first deflection 44 arranged. Their shape and position according to the invention is determined by the requirements that of the first deflection 44 incoming light 92 from the second deflection surface 46 as a parallel aligned and homogeneous light beam 50 is reflected. The light guide section 6 closes at the Lichteinkoppelbereich 4 so that the parallel aligned light beam 50 when entering the Lichtleitabschnitt 6 has a direction that it when first hit a light guide surface 16 of the light guide section 6 There at an angle of 45 degrees to 75 degrees, for example, an angle of 60 degrees to the solder on the light guide surface 16 lets happen.

In a preferred embodiment, the thickness of the light guide is 2 in his Lichtleitabschnitt 6 between 3 mm and 12 mm. A light-emitting diode used as a light-emitting diode is then to be arranged so that the center of their light entrance surface 42 directed light exit surface in the center of the spherical shape of the light entry surface 42 of the light guide 2 lies. The spherical form appears in the section that appears in the 13 is visible, as a circular shape. The light exit surface of the LEDs is typically about one square millimeter in size. In such an arrangement, the rays emanating from the center of the LED chip perpendicularly pass over the circular light entrance surface 42 in the light guide 2 and experience no direction-changing refraction.

After passing through the reflections on the first deflection surface 44 and the second deflection surface 46 As the light beam transforms, the light propagates through repeated total reflection along the light guide section 6 of the curved light guide 2 out.

On the first, curved deflection surface 44 is a surface normal 94 together with two beams of light 96 . 98 shown below the critical angle of total reflection at the base of the normal 94 to meet. Rays that are to the left of the normal 94 on the first, curved deflection surface 44 meet, fall too steeply and do not meet the condition for total reflection, rays that are to the right of the normal 94 are subject to total reflection. The entire illustrated beam path is thus obtained in particular when either the entire first, curved deflection surface 44 is mirrored, or if at least the left of the normal 94 lying part is mirrored. A mirroring is preferably carried out by a metallic coating. Another way to achieve complete reflection is based on the use of a roof edge shaped surface.

The effects of cooperating first deflection 44 and second deflection surface 46 are the following: After the reflection at the second deflection surface 46 the rays go 50 parallel to each other, and the two rays each have the same distance to their neighboring beams after double reflection, are thus equidistant. The between the first deflection 44 and the second deflection surface 46 running rays 92 are not yet parallel to each other. The from the second deflection 46 outgoing rays 50 meet at the angle of 45 degrees to 75 degrees, for example, an angle of 60 degrees to the normal to the actual light guide surfaces, so in particular to the light guide surface 16 ,

Claims (13)

A light guide (2) for a lighting device of a motor vehicle having a light coupling region (4) and a first light guide section (6), - the first light guide section (6) adjoining the light coupling section (4), characterized in that - a first deflection surface ( 44) of the Lichteinkoppelbereichs (4) is adapted to light, which emanates from a outside of the light guide (2) in front of a light entrance surface (42) lying point (48), to a second deflection surface (46), - that the first deflection (44) and the second deflection surface (46) are arranged by their respective shape and position to cooperate so that the outgoing light from the point (48) after the reflection at the first deflection surface (44) and the second deflection surface (46) forms a parallel aligned and homogeneous light beam (50), - that a second Lichtleitabschnitt (12) from a longitudinal side (14) of the first Lichtleitabschnitts (6) abrag t, and - that a transition region (10) between the first light guide section (6) and the second light guide section (12) in the direction of the Lichteinkoppelbereichs (4) comprises a cross-section decrease. The light guide (2) after the Claim 1 , - Wherein the second light-guiding section (12) protrudes flat and in one piece from the first light-guiding section (6). The light guide (2) after the Claim 1 - wherein the second light guide section (12) comprises a number of branches (52) projecting from the first light guide section (6), and - the crossing section (10) being divided into a number of crossing sections associated with the branches (52). The light guide (2) according to one of the preceding claims, - Wherein the transfer area (10) in the direction of the Lichteinkoppelabschnitts (4) recessed groove (40). The light guide (2) according to one of the preceding claims, - Wherein the transfer area (10) in the direction of the Lichteinkoppelabschnitts (4) tapered second Lichtleitabschnitt (12). The light guide (2) according to one of the preceding claims, wherein a light guide surface (16, 17) of the first light guide section (6), which in particular is associated with the convex longitudinal side (14) of the first light guide section (6), comprises in the direction of the light coupling section (4) a cross-sectional increase corresponding to the cross-section decrease. The light guide (2) according to one of the preceding claims, - wherein a convex curvature of the Lichteinkoppelbereich (4) facing away from the narrow side (22) of the second Lichtleitabschnitts (12) spans a first plane which is substantially parallel to or equal to a second plane, which spanned by a curvature of the first Lichtleitabschnitts (6) becomes. The light guide (2) according to one of the preceding claims, - Wherein the convex curvature of the Lichteinkoppelbereich (4) facing away from narrow side (22) of the second Lichtleitabschnitts (12) in such a way with the curvature of the first Lichtleitabschnitts (6), so that a light beam with substantially parallel light beams from a Lichtauskoppelbereich (26) is emitted , The light guide (2) according to one of the preceding claims, - Wherein the Lichteinkoppelbereich (4) facing away from the narrow side (22) of the second Lichtleitabschnitts (12) for light extraction comprises a light output surface. The light guide (2) according to one of Claims 1 to 8th wherein the narrow side (22) of the second light guide section (12) facing away from the light coupling region (4) comprises a deflection surface (56) which is inclined relative to a light coupling surface (58) of the second light guide section (12), and wherein a light guide surface (60 ) of the second Lichtleitabschnitts (12), which with the deflection surface (56) forms an acute angle, the light outcoupling surface (58). The light guide (2) after Claim 9 or 10 - wherein the second light guide section (12) comprises a further light output surface (70; 72) which extends substantially equidistant from the narrow side (22). The light guide (2) according to one of the preceding claims, - Wherein the first Lichtleitabschnitt (6) connects to the Lichteinkoppelbereich (4), that a parallel aligned and homogeneous light beam (50) on entering the first Lichtleitabschnitt (6) has a direction which the light beam (50) at the first impact on one of the light guide surfaces (16) of the first Lichtleitabschnitts (6) there at an angle to the solder on the light guide surface (16) impinges, which is greater than the critical angle of total internal reflection. An illumination device for a motor vehicle, which comprises a light guide (2) according to the preceding claims and a light source associated with the light guide (2).

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