EP2884157B1 - Motor vehicle headlamp - Google Patents

Description

The present invention relates to a motor vehicle headlight having the features of the preamble of claim 1.
Such a motor vehicle headlight is from the DE 10 2010 023 359 A1 known. The known headlamp has at least one semiconductor light source and one primary optic, which is set up to collect light emanating from the semiconductor light source and to direct it to secondary optics. The primary optics absorbs the light from the light source via at least one light entry surface and couples it out via a light exit surface. The primary optics has a connection flange with which it is held on a holder in at least two fixed bearings, which are arranged in a first plane which is parallel and at a distance from a second plane in which the at least one light entry surface lies. Other motor vehicle headlights with primary optics are off DE 10 2012 213 843 B3 and US 2008/0253144 A1 known. The light exit surface of semiconductor light sources used for motor vehicle headlights is typically in a rectangle with an edge length of between 0.5 and 2 millimeters. In order to receive the largest possible part of the light emitted by the semiconductor light sources, the distance of the light exit surface of the semiconductor light source from the light entry surface of the primary optics is only a few tenths of a millimeter. The length of the primary optic, which lies between its light entry surface and its light exit surface, is typically a few millimeters. It is, for example, in a range of 5 to 15 mm, this range is only to illustrate typical size ratios and in other examples may be outside the specified limits.

Semiconductor light sources reach temperatures of over 100 ° C during operation. Due to the closely adjacent arrangement of the semiconductor light sources and the primary optics results in a thermal coupling, which can lead to a heating of the primary optics and thus to a change in distances within the headlamp by thermal component expansion. Further temperature influences on such distances result from the surroundings of the headlight. Automotive technology achieves headlight ambient temperatures that can exceed 100 ° C. This is especially true when installed in the vicinity of an internal combustion engine of a motor vehicle. In cold weather, the ambient temperatures can also assume high values in the negative range.

It has been found that the resulting large temperature differences exert undesirable effects on lighting headlamp characteristics such as the coupling-in and / or the coupling-out efficiency and thus the Light distribution and thus also the fulfillment of legal requirements or customer requirements can negatively influence. In addition, it has been found that with narrow gaps between light exit surfaces of semiconductor light sources and light entry surfaces of primary optics, mechanical damage to the semiconductor light sources can occur.

A reduction of the distance between the light exit surface of the semiconductor light sources and the light entry surface of the primary optics may, for example, lead to an undesired mechanical contact of these surfaces and thus to a damage of the semiconductor light source.

The known headlight compensates the thermal expansion of the primary optics by an oppositely acting thermal expansion of the holder, however, has the disadvantage that the relevant dimensions of the primary optics and the holder must be the same in order to achieve complete compensation of the thermal expansion of the primary optics. This means that the length of the thermally expanding holder with the same coefficient of expansion must correspond to the distance between the light entrance surface and the light exit surface of the primary optics. In reality, the first level (fixed storage level) is usually at a distance from the second level (light entry area level). As a rule, the light entry surfaces are only arranged at a very small distance from the light sources, in order to couple in as much of the light emanating from the light sources into the primary optics. However, it is not possible to arrange the fixed bearing directly at the height of the light exit surfaces. This is because the boards on which the light sources are arranged, besides the light sources and the conductor tracks which serve to supply the light sources with electrical power, they also have other, usually electronic components, which have a certain height with which they project beyond the light sources. It is therefore often not possible to arrange the bearings of the holder in the plane in which the light exit surfaces of the light sources are located.

Against this background, the object of the invention in the specification of a motor vehicle headlamp, in which a holder of the primary optics is formed so that the thermal change in length of the primary optics between the light entrance surface and light exit surface is as fully compensated without the bearings of the holder are in the same plane like the light entry surface of primary optics.

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

The headlight according to the invention is characterized in that a first portion of the Anbindungsflansches, which is located between a part held in the fixed bearing part of the Anbindungsflansches and the light exit surface, dome-like, wherein the light exit surface is located on the convex side of the curvature.

The dome-like bulge of the first section and the fixation of the primary optic between two fixed bearings cause the primary optic to bulge upwards in a thermally induced expansion of the primary optic between the two fixed bearings. The bulge arises from the fact that a central area of the primary optics between the fixed camps expands due to an increase in temperature, while a distance between the two fixed camps due to a different coefficient of linear expansion of the bearing having the bearing only slightly or ideally not changed.

Due to the stress build-up in the plane of the clamping, the expansion is forced in the direction of the dome shape, so that the clamped between the fixed bearings part bulges further. As a result, the central area moves away from the light sources, drawing with it the light entering ends of the primary optics which adjoin the central area. As a result, the light entry surfaces, which delimit the light entry ends in the direction of the light sources, are moved away from the light sources, so that an approach of the light entry surfaces of the primary optics to the light exit surfaces of the semiconductor light sources resulting from a thermally induced change in the length lying between the light entry surfaces and the light exit surface Primary optics is compensated.

Furthermore, it is proposed that the primary optic is made of silicone. Silicone is a highly transparent material and has a high temperature resistance. Some silicones are particularly thin in the production phase and can be sprayed during the injection molding in extremely filigree structures, which is advantageous for the production of thin optical fiber ends.

A further embodiment provides that the connection flange is made of the same material as the primary optics. Silicone, for example, an elastic material that is good form and / or non-positively fixed in the holder, even if the holder has manufacturing tolerances.

In addition, it is proposed that the connection flange is integrally connected to the primary optics. As a result, the primary optics and the connection flange can be produced together in one process step cost-effectively as a one-piece component by injection molding.

Furthermore, it is proposed that the connection flange is designed to run around the light exit surface of the primary optics. The peripheral connection flange has the advantage that a translation of the primary optics in two spatial directions is positively blocked by mechanical stop of the connection flange to the bracket.

A further embodiment provides that the holder has a receptacle and an insert, wherein the receptacle is positively and / or positively connected to the insert. Between the receptacle and the insert of the Anbindungsflansch the primary optics is fixed in force and / or positively fixed in the holder. The non-positive and / or positive connection is realized for example as a screw, through which the insert is connected to the receptacle. By the screw connection in particular a clamping force is generated with which the primary optics is fixed non-positively in the holder. With such a holder designed in a simple manner two fixed bearings can be realized with which the primary optics is held on a basic structure of the headlamp.

In addition, it is proposed that the receptacle and the insert have a smaller coefficient of linear expansion than the primary optics. Thus, with a temperature change, the distance between the two fixed bearings changes to a lesser extent than the volume or Length of the primary optic between the two fixed camps. This ensures that the primary optic bulges when the temperature rises.

Furthermore, it is proposed that the first section is received in a gap between the receptacle and the insert, wherein the gap is wider than the material thickness of the first section. This gap gives room to the bulge of the primary optics. As a result of the bulge, the light entry surfaces of the primary optics move away from the light exit surfaces of the semiconductor light sources.

A further embodiment provides that the receptacle has a recess in which a light entry end of the primary optics is received. The recess forms a kind of guide, which permits a movement of the light entry end perpendicular to the light exit surface of the semiconductor light source, but blocks movements of the light entry surface of the primary optics transversely to the surface normal of the light entry surface.

Furthermore, it is proposed that the light entry end, viewed from the light entry surface, has an increasing cross section. The increasing with increasing distance from the light entrance surface cross-section causes a desired reduction of the opening angle of the propagating light in the primary optics, so that the light exits in bundled form through the light exit surface of the primary optics in the direction of a possibly but not mandatory secondary optics of the headlamp.

In addition, it is proposed that a cross-section of the light entry end extends abruptly as seen from the light entry surface, so that a first Stop surface is formed, which cooperates with a second stop surface, which is a part of the holder. The two abutment surfaces together form a mechanical stop, which prevents a collision of the light entry surface with the light source at large thermally induced changes in length of the primary optics.

It is also preferred that the light sources are arranged on a carrier element. The carrier element is part of the mounting structure and serves for fastening the semiconductor light sources to the base structure. In addition to the light sources, further electronic components and printed conductors are arranged on the carrier element, which serve to supply energy and / or control the light sources.

A further embodiment provides that the headlamp has a plurality of semiconductor light sources arranged in the manner of a matrix and a primary optic which is designed as an optical array with a plurality of matrix-like and optically active elements. In this case, the optically active elements concentrate the light emanating from the semiconductor light sources and direct it to the secondary optics arranged downstream in a beam path. In particular, when a length of the secondary optics transverse to the beam path is small compared to a length of the primary optics in this direction, the primary optic is preferably curved in a horizontal plane in the intended use. The curvature is concave, as seen from the secondary optics, so that the light decoupled from the primary optics is focused on the secondary optics. This concave curvature of the primary optic, which is concave in the horizontal plane, is not influenced by the curvature according to the invention, which is convex from the point of view of secondary optics, since the profile of the convex curvature passes through suitable arrangement of the fixed bearing preferably lies in a vertical plane.

Further advantages will be apparent from the dependent claims, the description and the attached figures.

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.

Figur 1

eine Kraftfahrzeugbeleuchtungseinrichtung nach dem Stand der Technik in einer Schnittdarstellung als Umfeld der Erfindung;

Figur 2

eine Primäroptik eines erfindungsgemäßen Kraftfahrzeugscheinwerfers und eine Halterung für die Primäroptik in einer Schnittdarstellung;

Figur 3

eine Detailansicht eines Lichtmoduls in einer Schnittdarstellung;

Figur 4

eine Anordnung einer Sekundäroptik und einer Primäroptik für eine Ausgestaltung des erfindungsgemäßen Kraftfahrzeugscheinwerfers.

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:

FIG. 1

a motor vehicle lighting device according to the prior art in a sectional view as the environment of the invention;

FIG. 2

a primary optics of a motor vehicle headlight according to the invention and a holder for the primary optics in a sectional view;

FIG. 3

a detailed view of a light module in a sectional view;

FIG. 4

an arrangement of a secondary optics and a primary optics for an embodiment of the motor vehicle headlight according to the invention.

The FIG. 1 shows a sectional view of a motor vehicle headlight 10 with a light module 12. In Other embodiments, the headlight 10 may also have a plurality of light modules 12. The light module 12 has semiconductor light sources 14, a primary optics 16 and a secondary optics 18. The light module 12 is arranged in a housing 20 of the headlamp 10. The housing 20 has a light exit opening, which is covered by a transparent cover 22.

The light sources 14 are arranged on a carrier element 24. On the support element 24, in addition to the light sources 14, further electrical components and conductor tracks are arranged, which allow an electrical supply and control of the light sources 14, which is not shown here for reasons of clarity. The carrier element 24 is generally a rigid or flexible circuit board and is usually in thermal contact with a heat sink, not shown in the figure, which is arranged and arranged to receive the heat generated during operation of the light sources 14 and to the environment leave. Each of the semiconductor light sources 14 has a respective individual light exit surface 17.

The primary optics 16 is set up to collect light emitted by the light exit surfaces of the light sources 14 and to direct them to the secondary optics 18. For this purpose, the primary optics 16 have light entry surfaces 26. Through the light entry surfaces 26, light enters one of the light sources 14 in each case into a light entry end 27 of the primary optics 16. The distance d1 between the light exit surfaces of the light sources and the light entry surfaces of the finger-like light entry ends 17 of the primary optics is only a few tenths of a millimeter in size and can be influenced by the linear expansion of the components. The primary optic expands with increasing Temperature stronger than the holder 34, it may come to a contact of primary optics and light sources, which must be avoided at all costs. The light entry end 27 has an increasing cross section viewed from the light entry surface 26. The light entry end 27 conducts the light by total internal reflection in the direction of a light exit surface 28. The light is extracted from the primary optics 16 through the light exit surface 28.

The secondary optics 18 is adapted to receive light, which is coupled out of the primary optics 16 via the light exit surface 28, and to direct it into a rule-compliant light distribution in the apron of the headlamp and thus in particular on a roadway ahead of the vehicle.

At this point, a thought Cartesian coordinate system is introduced, which is for the FIG. 1 and all subsequent figures have validity. The x-axis of the coordinate system points in the direction of a main light exit direction 30 of the headlight 10 and thus into the apron of the vehicle. The y-axis points in the FIG. 1 into the plane of the drawing and the z-axis points in the FIG. 1 up. The y-direction is preferably aligned parallel to a transverse axis of the vehicle in a proper use of the headlamp in the vehicle. The z-axis is preferably aligned parallel to the vertical axis.

The light module 12 has mounting structures by means of which the at least one semiconductor light source 14, the primary optics 16 and the secondary optics 18 are fastened to a base structure 32. In the illustrated embodiment, the support structures have three separate Parts on, namely the support member 24, with which the semiconductor light sources 14 are fixed to the base structure 32, a holder 34 of the primary optics 16 and a holder 36 of the secondary optics 18. With reference to the following FIG. 2 the operation of a features of the invention having bracket 34 of the primary optics 16 is explained in more detail.

FIG. 2 shows in a sectional view a primary optic 16 and its holder 34. The sectional plane is parallel to the xz plane. In this embodiment, the holder 34 of the primary optics on two elements. The first element is a receptacle 38, which is connected to the base structure 32. The base structure 32 corresponds functionally to the base structure 32 of FIG FIG. 1 and is in the FIG. 2 not shown for reasons of clarity. The second element is an insert 40, which is positively and / or non-positively connected to the receptacle. Between the receptacle 38 and the insert 40 a Anbindungsflansch 42 of the primary optics 16 is arranged. The attachment flange 42 is preferably integrally connected to the primary optic 16.

Preferably, the primary optic 16 is made of silicone. Silicone is a highly transparent material and has a high temperature resistance up to approx. 260 ° C. Certain types of silicone are particularly thin in the production phase and can be sprayed into filigree structures as part of an injection molding process. Silicone is also an elastic material. Due to the elasticity of the primary optics 16 can be well frictionally received in the holder 34, furthermore, manufacturing tolerances of the holder 34 can be well balanced so that a primary optics 42 can be positioned by means of Anbindungsflansches exactly in relation to the light sources. Due to the above described properties of the material, it is preferred to manufacture the connection flange 42 and the primary optics 16 of silicone. Particularly preferred is the production of primary optics 16 and connecting flange 42 as a one-piece component, for example by injection molding. In other embodiments, the primary optics 16 and / or the attachment flange 42 are made of glass, plastic or a technically comparable material.

The connection flange 42 has two first sections 44, which in the FIG. 2 above and below the light exit surface 28 directly connect to this. The first sections 44 are dome-shaped. Viewed from the location of the light entry surfaces 26, the curvature of the first sections 44 is concave. Each of these first sections 44 is followed by a second, vertical section 46. It should be noted that the terms "vertical" and "horizontal" with respect to the intended use of the headlight in the motor vehicle. In the FIG. 2 and the following figures, therefore, the term "vertical" an extension in the direction of the z-axis and the term "horizontal" an extension in the direction of the x-axis and / or the y-axis. The vertical section 46 is perpendicular to the main emission direction 30. These vertical sections 46 are followed in each case by a third, horizontal section 48. The third sections 48 extend from the second sections 46 perpendicular to them in the main emission direction 30.

The two horizontal portions 48 abut respectively on designated surfaces 50 of the second insert 40, so that in the FIG. 2 top surface 50 of the insert blocks downward movement of the upper horizontal section 48 of the primary optic and the lower surface 50 the insert blocks upward movement of the lower horizontal portion 48 of the primary optic. The horizontal portions 48 and the surfaces 50 thus act together so that a translation of the primary optics 16 is blocked in the vertical direction.

The two vertical sections 46 of the primary optics are fixed between the receptacle 38 and the insert 40 by a clamping force acting perpendicular to the vertical sections 46. The clamping force is generated in that the receptacle 38 and the insert 40 by means of a non-positive and / or positive connection, such as by a screw 49, are connected so that the vertical portions 46 of the primary optics between the receptacle 38 and the insert 40th be trapped. The clamping of the vertical sections 46 initially prevents a translation of the primary optics 16 in the direction of the x-axis. With a sufficiently large clamping force and a movement of the vertical portions 46 and thus a translation of the primary optics 16 in the direction of the y-axis is prevented by adhesion.

The positive locking of the horizontal portions 48 of the primary optics by the surfaces 50 of the insert 40 and the force between the insert 40 and the receptacle 38 and positive fixing of the vertical portions 46 of the primary optics prevent translation of the primary optics 16 in three spatial directions. In order to additionally prevent the translation of the primary optics 16 in the direction of the y-axis by positive locking, the connecting flange is preferably designed to run around. Also conceivable is a mechanical stop in the direction of the y-axis.

Viewed purely mechanically, the sections 48 form the primary optics and the surfaces 50 of the insert and the by the clamping forces fixed vertical sections 46 of the primary optics with respect to the x-direction and the y-direction, an upper and a lower bearing 52, in which the primary optics 16 is held in the holder 34. The two fixed bearings 52 are in a first level 100. The first level 100 is in the FIG. 2 perpendicular to the plane of the drawing and lies parallel to a second plane 102 in which the light entry surfaces 26 of the primary optics 16 lie. The first level and the second level have a distance a, which is in any case so large that arranged on the support member 24 components 104, which rise from there higher than the light source 14, no mechanical contact with the mechanical components of the in the second level 100 have lying fixed bearing.

With a temperature increase in the headlight 10, the primary optic 16 expands between the two fixed bearings 52. Due to different expansion coefficients of primary optics 16 and holder 34, the holder 34 expands less strongly. Therefore, the distance between the upper and lower fixed bearing 52 does not change or at least less than the length of the clamped between the fixed bearings 52 primary optics 16. Under these conditions, this change in length leads to a bulge of the primary optics 16 in the x direction. A central region 53 of the primary optics 16 moves in the x direction and pulls the light entry ends 27 of the primary optics, which adjoin the central region 53 in the x direction, away from the light exit surfaces of the semiconductor light sources 14. As a result, an approximation of the light entry surfaces 26 of the primary optics 16 to the light exit surfaces of the semiconductor light source 14, which is caused by a thermally induced elongation of the primary optics, compensated in part.

The dome-shaped configuration of the first sections 44 determines the direction of the bulge.

The dome-shaped portions 44 lie in a gap 56 between the receptacle 38 and the insert 40. The width of the gap 56 is slightly greater than the material thickness of the dome-shaped portion 44, so that there is a gap. This space gives the bulge space.

In an advantageous embodiment, the materials from which the receptacle 38 and the insert 40 are made, a much smaller coefficient of linear expansion, as the material from which the connection flange 42 is made. This results in a change in temperature at the receptacle 38 and the insert 40, a lower elongation or shrinkage than at the Anbindungsflansch 42. As a desired consequence, the positions of the fixed bearing 52 with respect to the housing 20 remain largely preserved.

At one in the FIG. 2 illustrated embodiment, the receptacle 38 recesses 58. In the recesses 58, the light entry ends 27 of the primary optics 16 are received. The recesses 58 act in the drawing plane as guides or floating bearing. That is, the recesses 58 allow translation of the primary optics 16 in the x direction and at the same time prevent translation of the light entry ends 27 in the direction of the z axis and preferably also in the direction of the y axis. Due to the bulge on the light exit side, compressive stresses along the z-direction are induced in the primary optics 16 on the light entry side. These compressive stresses cause, in particular in primary optics 16, which, like the embodiment shown here, have a plurality of light entry ends 27, that the light entry surfaces on an arc would be shifted against each other by the y-axis. The recordings of the light entry ends 27 in the recesses 58 prevent these displacements of the light entry surfaces 26, since they limit the possibilities of movement of the light entry ends 27.

The FIG. 3 shows a detail of the light module 12 in the region of the light entry surface 26. In this area, the light entry end 27 of the primary optics 16 has a return 60. That is, viewed in the direction of the light entry surface 26, the cross section of the light entry end 27 decreases abruptly. As the primary optic 16 expands due to an increase in temperature, the recess 60 may abut a stop surface 62 attached to the base structure. The stop surface 62 and the recess 60 are arranged and arranged to limit the thermally induced movement of the light entry end in the direction of the semiconductor light source, which is symbolized here by an arrow 64, by a mechanical stop 14. As a result, the risk of a collision of the light entry surface 26 of the primary optics 16 with the semiconductor light source 14 is prevented.

The FIG. 4 shows the primary optics 16 and the secondary optics 18 of a headlamp 10. In this embodiment, the headlamp 10 has a plurality of semiconductor light sources arranged in a matrix-like manner, from which light emanates. In a beam path of the outgoing light from the semiconductor light sources 14, the primary optics 16 is arranged. The primary optics 16 is designed as an optical array 66 with a plurality of optically active elements 68 arranged in the form of a matrix. The optically active elements 68 focus the light emanating from the semiconductor light sources 14 and direct it to the secondary optics 18 arranged in the beam path. For secondary optics 18, their dimensions are small compared to a longitudinal extent of the optical array 66, it is known to concave curve the optics array 66 in a horizontal plane when used as intended from a secondary optics 18 perspective. As a result, focusing of the light on the secondary optics 18 and / or the arched Petzval surface of the secondary optics 18 is achieved. The above-described convex curvature of the primary optic 16, viewed from the secondary optics 18, which serves to completely compensate for a longitudinal expansion of the optical elements 68, is also used in such an optical array 66. The curved first sections 44 are arranged on the long sides above and below the optical array 66. The light exit surfaces of the individual optimally effective elements of the primary optics 16 designed as optic array 66 are in each case preferably arched in a vertical plane. The concave curvature of the optical array 66 in the horizontal plane remains unaffected.

Claims (13)

1. A motor vehicle headlight (10), having at least one semiconductor light source (14) and a primary optical element (16) that is arranged for gathering light, originating at the semiconductor light source (14), and aiming it at a secondary optical element (18), and the primary optical element (16) receives the light of the semiconductor light source (14) via at least one light entry surface (26) and decouples it via a light exit surface (28), and the primary optical element (16) has a fastening flange (42), with which it is retained in a mounting (34) in at least two fixed bearings (52), which are located in a first plane that is parallel to and spaced apart by a distance (a) from a second plane, in which second plane the at least one light entry surface (26) is located, characterized in that a first portion (44) of the fastening flange (42), which is located between a part of the fastening flange (42) of the fixed bearing (52) and the light exit surface (28), is curved in domelike fashion, and the light exit surface (28) is located on the convex side of the curvature.
2. The motor vehicle headlight (10) of the foregoing claim 1, characterized in that the primary optical element (16) is made from silicone.
3. The motor vehicle headlight (10) of one of the foregoing claims, characterized in that the fastening flange (42) is made from the same material as the primary optical element (16).
4. The motor vehicle headlight (10) of one of the foregoing claims, characterized in that the fastening flange (42) is integrally joined to the primary optical element (16).
5. The motor vehicle headlight (10) of one of the foregoing claims, characterized in that the fastening flange (42) is embodied in wraparound fashion.
6. The motor vehicle headlight (10) of one of the foregoing claims, characterized in that the mounting (34) has a receptacle (38) and an insert (40), and the receptacle (38) is connected to the insert (40) by nonpositive and/or positive engagement.
7. The motor vehicle headlight (10) of claim 6, characterized in that the receptacle (38) and the insert (40) have a smaller coefficient of longitudinal expansion than the primary optical element (16).
8. The motor vehicle headlight (10) of one of the claims 6 and 7, characterized in that the first portion (44) is received in a gap (56) between the receptacle (38) and the insert (40), and the gap (56) is larger than the material thickness of the first portion (44).
9. The motor vehicle headlight (10) of one of the claims 6-8, characterized in that the receptacle (38) has a recess (58), in which a light entry end (27) of the primary optical element (16) is received.
10. The motor vehicle headlight (10) of claim 9, characterized in that the light entry end (27) has an increasing cross section as viewed from the light entry surface (26).
11. The motor vehicle headlight (10) of one of claims 9 and 10, characterized in that a cross section of the light entry end (27) widens abruptly, viewed from the light entry surface (26), so that a first stop face (60) is created that cooperates with a second stop face (62).
12. The motor vehicle headlight (10) of one of the foregoing claims, characterized in that the semiconductor light sources (14) are located on a support element (24).
13. The motor vehicle headlight (10) of one of the foregoing claims, characterized in that the headlight (10) has a plurality of semiconductor light sources (14) arranged in matrixlike fashion and a primary optical element, which is designed as an optical array (66) having a plurality of optically active elements (68) arranged in matrixlike fashion, and the optically active elements (68) focus the light that originates at the semiconductor light sources (14), and aim it at the secondary optical element (18) located in a beam path.

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