DE102011114636A1 - Arrangement and dimensioning of overhead elements on a projection lens of a motor vehicle headlight - Google Patents

Abstract

Disclosed is a method for the arrangement of overhead elements of a projection lens of a motor vehicle projection headlamp, wherein the overhead elements are adapted to direct light in a lying over the cut-off line overhead range of the light distribution of the headlamp. The method is characterized in that, in a first step, subareas of the interface are defined, that in a second step, overhead elements are arranged, which are arranged in the subareas defined in the first step, such that an overhead resulting from the simulated overhead elements Lighting is simulated, wherein the simulation of the defined overhead elements is used to iteratively change a number and / or shape of the defined overhead elements so that the simulated overhead lighting meets predetermined conditions. An independent claim is directed to a headlamp equipped with such overhead elements,

Description

The present invention relates to a method according to the preamble of claim 1 and a headlamp according to the independent device claim.

Such a method and such a headlight are from the DE 10 2009 020 593 A1 known.

This document shows in particular a motor vehicle projection headlamp which is adapted to project an edge which limits a luminous flux of a light source of the headlamp as a cut-off of a light distribution generated by the headlamp in the apron, and a projection lens with geometrical overhead Having elements that are implemented as local deformations of an interface of the projection lens and which are adapted to direct light in a light-dark-border overhead overhead area of the light distribution. By instructing to discreetly distribute more than one hundred such overhead elements across the interface of the projection lens, this document also implicitly shows a method according to the preamble of claim 1.

The light-dark boundary of a low-beam distribution delimits a lower, brightly illuminated area of the light distribution from an upper, darker area. The upper area is known to be weaker illuminated to reduce dazzling other road users, especially oncoming traffic.

In the ECE law area certain spot-dependent illuminance levels are required for motor vehicle headlamps. These are formulated separately for dipped and main beam on the basis of numerous measuring points. In particular, the present invention relates to the measurement points prescribed for a low beam. An illustration of measurement points for the illuminances can be, for example, the Automotive Handbook, 24th Edition, April 2002, ISBN 3-528-13876-9, page 816 be removed.

In addition to predetermined illuminance levels of the incident on the street light, so for the illumination of the lying below the cut-off line bright area of the light distribution, special requirements for illuminance levels above the cut-off line must be met. This region of the light distribution above the cut-off line is also referred to as an overhead or signlight area (derived from the visibility of the traffic signs).

The legal measuring points in this range extend up to 4 ° above the horizon and are characterized by minimum or maximum values as well as so-called summation values for the illumination intensity which is established in each case at the measuring points.

Dipped-beam projection systems have very little light above the cut-off line due to the system, because this overhead range is effectively shaded by the aperture used in projection systems. It is this aperture whose edge is projected as a light-dark boundary in the light distribution in front of the headlight, so in particular in front of the vehicle.

Because of the effective shading, special measures are necessary to sufficiently illuminate these measuring points with suitable amounts of light. At the same time, attention must be paid to compliance with prescribed maximum values close to the cut-off line. These maximum values are also referred to as so-called glare values.

In known devices, this is achieved by locating local deformations on the front (light exit) or rear (light entry) interface of the projection lens, which deflect light into the Signlight measurement points by virtue of their additional prismatic, ie light-refracting action. This is for example from the DE 10 2004 024 107 A1 known in this context has a horizontally extending in the middle of the lens interface cylinder portion. From the DE 103 094 34 is a projection lens with a purpose serving local depression in the lower part of the lens known. Similar to this device is the subject of US Pat. No. 7,040,789 B2 which uses a type of ribs which are arranged circumferentially on the lens edge. Also known are serpentine elements on the front surface of the projection lens, as shown in the US Pat. No. 7,025,483 B2 to be discribed.

A local deformation of the lower lens region of the projection lens with an additional, horizontally scattering superstructure is from the patent DE 20 2005 004 080 known.

It is also known to provide the lens rear surface with prismatic deflecting elements for generating light for a secondary illumination area, as is the DE 10 2004 024 107 A1 can be seen. The already mentioned at the outset DE 10 2009 020 593 uses many regularly distributed on the projection lens, small prismatic elements for refraction of light in an overhead area.

Furthermore, geometrical surface modifications are known which, however, are not primarily directed to the illumination of overhead measurement points: these include, for example, lenses with horizontally and obliquely running wave structures. This is known both for the European ECE Legislative Area and for the American SAE Legislative Area. As an example, on the DE 40 31 352 A1 directed. Lenses with cylindrical elements are in utility model G 90 00 395 described.

In addition, the use of reflective additional components in the projection system is possible, such as the use of transversely reflecting aperture. An example of a reflective additional component which is arranged directly behind the projection lens is the US 5,307,247 refer to.

Also conceivable are other solutions, such as openings in the Abblendlichtblende. Such openings can also be partially combined with additional, reflective components. An opening in the aperture is, for example, in the KR 10 2009 0064 724 A and in the KR 10 2010 0069 471 A described.

Any deformation of a light entrance interface or a light exit interface of the projection lens used to produce overhead light is visibly perceptible visually since the generation of overhead light requires relatively large deflection angles of at least several degrees. Accordingly, a macroscopic, "invisible" solution on the projection lens can not exist.

This is important in light of the fact that design aspects are increasingly becoming the focus of current headlamps. This means that the acceptance of previously known overhead solutions on projection lenses on the side of the headlamp purchasers is decreasing. The appearance of headlamps is thus judged by customers increasingly critical, so that the appearance and in part to the function of the headlights increasingly much higher demands are made.

The appearance of the projection lens in the on state also plays an increasing role, so that solutions in which a sharp, punctual lighting of the lens is generated, are not desired.

Accordingly, many previous solutions are no longer usable because they are no longer accepted by the customer.

From the law side, a tightening of the regulations for overhead values is to be expected at the moment, which are partly not possible with the previous solutions. Thus, on the one hand, higher amounts of light are prescribed at individual measuring points in the overhead area. On the other hand, it is required in parallel to keep the glare values within the previously permitted limits. In addition, new measuring points to be illuminated have been introduced. Previous solutions also lead to an increase in the overhead light level according to an increase in the glare beyond the permitted limits, so that such headlights may not be allowed under certain circumstances.

In addition, previous solutions sometimes result in side effects in the light distribution: Since light must be taken from the normal low-beam light distribution for the overhead component, this can lead to inhomogeneities within the light distribution on the road, which are perceived as holes, ie as clearly visible darker areas become.

Previous overhead light solutions also have the disadvantage that they are usually compatible only with a specific projection system. If these solutions are applied to another projection system, the targets for the measured values to be achieved, neutrality with regard to the performance and homogeneity of the light distribution are generally not achieved. The overhead solution does not fit then.

In its method aspects, the invention proposed here is characterized in that subregions of the boundary surface are defined in a first step, that in a second step overhead elements are defined, which are arranged in the subregions defined in the first step, that one of the simulated subsystems Overhead elements resulting in overhead lighting is simulated, wherein the simulation of the defined overhead elements is used to iteratively alter a number and / or shape of the defined overhead elements so that the simulated overhead illumination satisfies predetermined conditions.

As a result, the invention provides in its method aspects a modular principle which leads step by step to an individually adaptable to each projection system overhead solution.

At first suitable positions for the geometric elements are found. Size and design of the geometric elements for generating overhead light can then be easily dimensioned by photometric simulation and analysis targeted. Thus, for each projection system, it is possible to simultaneously comply with the required measured values, the preservation of the Optimize and achieve the efficiency of the system and the homogeneity of the light distribution.

For the production of light in the overhead region of the dipped beam of projection systems, for this purpose, precisely adaptable geometric elements are proposed on the surface of the projection lens which, due to their small size, have an aesthetically pleasing and desired appearance.

In its device aspects, a particularly preferred embodiment is characterized in that the overhead elements are confined to three subregions of the interface wherein two of the three subregions are symmetrical to the optical axis of the headlamp and perpendicular to the horizon and optical axis and thus vertical arranged aligned imaginary plane, when the headlamp is aligned so that it generates a light distribution with a rule-compliant, at least partially parallel to the horizon light-dark boundary, and that the third region in such an orientation in a lower half of the interface so is arranged to be divided from the vertically oriented imaginary plane into two equal halves.

As a result of the two symmetrically arranged partial regions and the central region arranged at the bottom, an inconspicuous, desired and, in particular, aesthetically appealing appearance of the entire lens due to its symmetry is achieved, so that the lens can be regarded as a design element. The deliberately chosen appearance of the overhead geometries avoids, in particular by its symmetry, the subjective impression of a defective lens.

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 can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

drawings

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. In each case, in schematic form:

1 a sectional view of a motor vehicle headlight as a technical environment of the invention;

2 a cross-section through an embodiment of an overhead element of the 1 ;

3 a plan view of an overhead equipped with projection lens; and

4 a light distribution with an overhead distribution, which has been generated with a headlamp produced by the method according to the invention.

1 shows in detail a schematic representation of an embodiment of a headlamp 10 in a longitudinal section. The headlight 10 has a housing 12 with a light exit opening on, by a transparent cover 14 is covered. In the case 12 is a projection module 16 arranged. The projection module 16 has a light source 18 and a reflector 20 on, at least part of the light source 18 reflected outgoing light and bundles in a focal area. The reflector 20 is preferably in the form of an ellipsoid of revolution or a different ellipsoid-like freeform. The light source 18 is in a first focus F _{1 of} the reflector 20 arranged. An aperture arrangement 22 shields at least part of the reflector 20 outgoing luminous flux. The aperture 22 is in the representation of 1 arranged in a plane perpendicular to an optical axis 24 and through the second focus F2 of the reflector 20 runs. The aperture 22 but can also be parallel to the optical axis 24 be arranged horizontally and have a light-reflecting surface. In any case, however, the aperture edge lying in the region of the second focal point F2 becomes a light-dark boundary in the apron of the headlight 10 projected.

The projection is done by a projection lens 26 , The projection lens 26 is in the illustrated embodiment by means of a collar 28 engaging lens holder (not shown) at a front edge of the reflector 20 attached. The Lens 26 consists of any translucent material, for example. Of a temperature-resistant plastic or glass and has at the light source 18 facing side a substantially planar light entrance interface 30 and on its opposite side a convex light exit interface 32 on. Of course, the interface 30 also be concave or convex.

The light module 16 serves to generate a light distribution with light-dark boundary, preferably a low beam distribution or a fog light distribution. The light-dark boundary results as a projection in the region of the second focal point F2 of the reflector 20 lying edge of the aperture arrangement 22 in the of the light module 6 on the roadway generated light distribution. The direction x is substantially parallel to the direction of the optical axis 24 , which corresponds to the main emission direction of the luminous flux and, with the headlamp installed 1 , parallel to the longitudinal axis of the vehicle. The z-direction is parallel to the vertical axis of the vehicle and points upwards. The y-direction is correspondingly perpendicular to the plane of the drawing and points into it. In the lower half of the projection lens 32 has the light exit interface 32 an overhead element 34 in the form of a local deformation of the interface, here a projection.

2 shows a cross section through an embodiment of an overhead element 34 of the 1 , as he is at a in the plane of the drawing 1 Guided cut results qualitatively. The cross section of the overhead element 34 splits into a first section 42 that between the points 38 and 40 lies, and a second section 46 up, between the points 40 and 44 lies. Below the vertical extent or length of the overhead element, here is the distance of the points 38 and 40 in the 5 Understood. The curvature of the first section 42 corresponds in a preferred embodiment, the curvature of a cylinder jacket. The to the section 42 associated surface of the overhead element 34 corresponds to a part of a lateral surface of an imaginary cylinder, the axis of which is installed in the vehicle headlight 1 parallel to the base of the vehicle within the lens 26 lies.

Alternatively, the contour 42 also be generated as a spline function or as a comparable mathematical function or as a combination of such functions. Preference is given to a continuously differentiable course of the edge curve resulting in the section when the curvature is variable in the z direction.

The first paragraph 42 creates the desired deflection effect. The section 46 serves only to realize a continuously differentiable and thus edgeless transition between the first section 42 of the overhead element 34 and the remaining interface 32 the lens 26 ,

The desired distracting effect is achieved by comparing the light beam 48 passing through the interface of the lens 26 in the area of the overhead element 34 passes through, with the light bundles 50 . 52 that go through to the overhead element 34 adjacent areas of the interface 32 go through, clearly. Compared to the not or only comparatively weak deflection of the light beam 50 and 52 as they pass through the interface 32 learns a part 48 ' of the light beam 48 a comparatively stronger deflection in the z-direction. Due to the comparatively stronger deflection becomes the light beam 48 ' distracted beyond the cut-off line while the part 48 '' of the light beam 48 is deflected into the low beam light distribution. The light bundles 50 . 52 illuminate the area below the cut-off line.

According to the division of the areas of the overhead elements 34 and the remaining light exit interface of the lens 26 be five percent to ten percent of the through the lens 26 while the remaining ninety to ninety five percent illuminate the area below the cut-off line.

In a preferred embodiment, a maximum deflection is one by an overhead element 34 deflected light beam 48 towards an adjacent light beam 50 . 52 that is not due to the overhead element 34 is distracted, at least five degrees.

So far, the invention has been based on the example of a light emission interface of a projection lens 26 explained. Alternatively or additionally, the locally selectively deflecting effect but also by a corresponding design of the light entrance interface of the lens 26 be generated. For vehicle headlamps whose light module 6 is not pivotable, the deflecting effect can optionally also be realized by a distribution of overhead elements on the light entrance interface of the cover.

In the following it will be described, as in successive individual steps and thus, so to speak, according to a modular principle, a positioning and configuration of adaptable geometric overhead elements 34 on the surface, for example on the light exit interface 32 a projection lens 26 takes place to produce well-defined light in the overhead area. This method is applicable in principle to any projection system.

By means of a new analysis method, the first step is to create a subarea on the projection lens interface 26 defined, which are suitable for the positioning of overhead elements. These sections should have the smallest possible dimensions and thus attract attention aesthetically.

The definition of the subregions becomes an interface of the projection lens 26 , for example the light emission interface 32 in mathematical decomposition into small segments. These segments are targeted examined for their suitability for the positioning of overhead elements 34 , At the end of the analysis, exact statements are obtained for the ideal positioning of the geometric elements. Undesirable side effects on the homogeneity of the light distribution or the efficiency of the projection system are prevented by this procedure.

3 shows a plan view of a light exit interface 32 a projection lens 26 with a preferred arrangement of subregions 54 . 56 and 58 , There are preferably two symmetrically arranged portions 54 and 56 and a centrally located below subarea 58 Are defined. This arrangement results in an unobtrusive, intentional and cosmetically pleasing appearance of the entire lens 26 , so that there is another degree of design freedom, or so that the lens 26 can be considered as a design element. The deliberately chosen appearance of the symmetrical arrangement of the subregions 54 and 56 in particular also avoids an impression of a defective lens, as it can be awakened, for example, in the case of a continuous overhead element in the form of a cylindrical sub-volume running across the lens.

In particular, the subregions are arranged in such a way that effects on the low-beam distribution that occurs below the cut-off line, where the overhead light is ultimately taken, are minimal. The homogeneity of the light distribution remains largely untouched.

So in the first step, there are subareas 54 . 56 . 58 defined on the interface of the projection lens, but need not necessarily be arranged as in the 3 is shown. It is essential that the subareas 54 . 56 . 58 suitable for an arrangement of overhead elements 34 , where the suitability results from the fact that the sub-areas 54 . 56 . 58 have as small dimensions and that a luminous flux through these subregions 54 . 56 . 58 passes through, can be deflected without disturbing effects on the rest of the light distribution in the above the cut-off line overhead overhead area of the light distribution.

In a preferred embodiment, the partial areas, for example the partial areas shown 54 . 56 . 58 such areas on the projection lens 26 that are traversed by light that does not exist in overhead elements 34 would serve to generate the cut-off line, that would contribute to the illumination of the bright area at or just below the cut-off line.

For the definition of the areas in the first step, the interface, for example, the light exit interface 32 the projection lens 26 disassembled into small segments. These segments are then examined specifically for their suitability for the positioning of overhead elements.

In a preferred embodiment, three subregions 54 . 56 . 58 defined, with two subareas 54 . 56 of the three partial areas symmetrical to one the optical axis 24 of the headlight 10 are arranged and arranged at right angles to the horizon and to the optical axis and thus vertically aligned imaginary plane when the headlamp is aligned so that it generates a light distribution with a rule-compliant, at least partially parallel to the horizon light-dark boundary. In the 3 this is the xz plane. The third area 58 becomes in such an orientation in a lower half of the interface 32 arranged so that it is divided by the vertically oriented imaginary plane into two equal halves, so that in this respect also results in a symmetry of the arrangement with respect to said plane.

The two symmetrically arranged subregions 54 . 56 preferably have a width of 4 to 5 mm with a length of about 10 mm. The lower middle area is preferably about 6 mm long and about 2.5 mm high. This is true for a lens 26 with a diameter of approx. 60 to 75 mm. With these values, the area occupied by overhead elements is only about 3% of the projected light exit surface of the projection lens 26 , This is much less than the even distribution after DE 10 2009 020 593 A1 , It is therefore preferred and at the same time an advantage of the invention that it is possible to achieve a legal requirement for sufficient overhead illumination with such a small proportion of the overhead element areas on the surface of the lens. In preferred embodiments, this area fraction is less than 5%. For the subregions is generally that the width is preferably between two mm and ten mm, with their length is preferably between one and twenty mm.

It is also preferred that the two laterally symmetrically arranged subregions 54 . 56 around a respective parallel to the optical axis and through the respective sub-area 54 or 56 passing through the axis of rotation are rotated so that they scatter light when described in claim 5 alignment of the headlamp not only upwards, but also to the side. The optical axis runs in the 3 parallel to the x-direction. The subareas 54 and 56 are preferred with overhead elements, for example with overhead elements 34 the Indian 2 shown type that these overhead elements through them divert passing light so that the light passed through each propagation direction components 60 . 62 having. These propagation direction components are characterized in that they not only have an upwardly directed component (in the z-direction), but additionally have lateral directional components, ie directional components pointing in the positive and / or negative y-direction. This achieves a desired width of the overhead illumination in the y direction.

In these sub-areas defined in the first step 54 . 56 . 58 become overhead elements in the second step 34 arranged. The overhead elements 34 preferably have a geometry that allows a defined generation of overhead light by their far-reaching adaptability. At the same time, targeted light control takes into account the maximum values to be observed (glare values) so that the legal requirements can be met safely.

A targeted adaptation of the geometry of the overhead elements is better than previously possible due to the large number of degrees of freedom in the geometric design. The overhead elements are C1-continuous, ie continuously differentiable in the interface, ie in the surface of the projection lens 26 integrated. In mass production this leads to an improved tool life.

The dimensioning of the geometric elements to be used in the subregions defined in the first step, be it the subregions 54 . 56 . 58 or other sub-areas defined in the first step, takes place by means of simulation and subsequent analysis. Due to the precisely defined geometry of the overhead elements 34 their effect can be predicted with good accuracy. So is a slight adaptation of the elements 34 to precise targets possible. This will save a considerable amount of time in determining the size, number and orientation of the overhead elements.

In this case, specifically smaller surface portions of the front surface of the projection lens are tilted relative to their previous orientation in the vertical direction. In other words, a z-component of a surface normal of the surface portion or surface area is increased. The light, which passes through these surface sections, respectively surface areas, undergoes a significant increase compared to its previous direction, ie an enlargement of the z-component of its propagation direction and then illuminates as a desired consequence the overhead area of the light distribution. This light is taken from the setting without such a tilting Abblendlichtverteilung.

The vertical deflection angle is varied within the tilted surface portions to cover the entire overhead measurement range. This creates a flat and homogeneous, albeit comparatively weakly lit, area in which all overhead measuring points are located. The maximum light deflection, which is achieved by the overhead elements, is at least 4 °, but can also be up to 10 °.

The against the surface 32 the projection lens 26 tilted surface portions are generally realized by cylinder sections. But they can also be limited by comparable or different mathematical functions or, for example, spline surfaces or a combination of them. The integration of the tilted individual surfaces in the surface of the projection lens is done by skillful rounding. Different, defined by mathematical functions rounding surfaces or free-form surfaces can be used. Even areas defined by spline functions can be used for this, differently defined areas are also possible.

The rounding is in particular such that there is at least one time continuously differentiable transition between the base 32 the projection lens 26 and the light deflecting surface portions, respectively, the overhead elements is generated. This soft integration into the projection lens 26 improves the life of the lens tool because there are no sharp edges that could be worn. The basic appearance and operating principle of the overhead elements is as already described 1 shown.

The arrangement and grouping of the overhead elements is not limited to an arrangement in a pattern of three partial areas. Depending on the lighting design of the projection system is a different positioning, number and size of the above-described overhead elements 34 suitable to generate a sufficient amount of overhead light, without having to accept a disturbing influence on the remaining light distribution.

For design reasons, the in the 3 but qualitatively illustrated arrangement of three sections with the described symmetry quite a preferred embodiment.

In each of these subareas, be it the three subareas 54 . 56 or 58 from the 3 or a different number or partitions, will have at least one overhead element 34 placed. In place of a cast with only an overhead element 34 one occupation of each group is preferred with only up to ten overhead elements, wherein the number of overhead elements in the symmetrically arranged subregions is preferably the same. As already explained, it is preferred that two groups in the two lateral regions of the projection lens (with respect to the vertical axis) and the third group in the middle region, preferably further down, placed.

An improved functionality of the overhead elements is achieved by the following measures:
The two lateral areas with overhead elements can additionally be rotated about their midpoint, the axis of rotation being parallel to the optical axis of the projection system. The rotation angle can be optimally adapted. The passing light is deflected not only upwards, but also targeted laterally. As a result of this measure, the illumination of measuring points (glare values) limited to the upper limit of the permitted illuminance is substantially reduced. At the same time, the overhead overhead measurement points are more illuminated, increasing the efficiency of the overhead elements.

Due to the compactness of the overhead elements within their subregions, they can be arranged on the surface of the projection lens in such a way that the required light can be removed without disturbing the remaining light distribution. Areas that have only a slight mixing of the light or are relevant to the performance of the projection system, can be omitted: In this way, for example, inhomogeneities or darkening in the area directly in front of the vehicle and in the side areas of the light distribution are suppressed.

Of particular importance is the group of overhead elements integrated centrally and preferably at the bottom of the lens front surface. in the 3 this is the one in the subarea 58 arranged group of overhead elements 34 , These support the side in the subregions 54 and 56 arranged elements 34 by making an additional contribution to the required overhead light.

At the same time, their preferential lateral scattering makes it possible to homogenize the light in the overhead area, exploiting the averaging effect arising along the y-direction. This generates a very uniform overhead light.

They also reduce the occurrence of inhomogeneities in the light distribution, because the light required in the overhead area is removed at a further, non-critical point of the lens surface.

The aesthetically improved appearance of the overhead elements is achieved in that instead of an extended over the projection lens overhead element or numerous discrete individual elements here very compact structures are used with physically small dimensions.

By dividing the deflecting surfaces into individual elements which are arranged one above the other or side by side, a very small height of the individual elements in the direction of their surface normal is achieved. This height is preferably in the range of 0.02 to 0.2 mm. In some cases, the use of only one element per group may be sufficient, here the division is omitted. This embodiment is preferred when only a correspondingly small area is required for the overhead elements.

The grouping of several, similar overhead elements in a delimited subarea and the symmetrical arrangement of the subareas result in a desired appearance, so that the elements are not to be confused with surface defects on the lens. The intended appearance is enhanced by the arrangement of the two lateral overhead areas extending symmetrically to the vertical axis and the central additional element.

An overall resulting light distribution with an overhead component generated according to the invention is in the 4 shown. H denotes a horizontal and V a vertical. The crossing point H = V = 0 represents the center of the light distribution. The H direction corresponds to the y direction used here, and the V direction thus corresponds to the z direction. The numbers are angular degrees. The closed curves are lines of equal illuminance, with the illuminance decreasing from the inside to the outside.

The measuring points M1-M6 to be illuminated with a minimum amount of light are safely in the sufficiently illuminated overhead area. At the same time, the light level does not increase any further towards the measuring points M4, M5, M6 located near the cut-off point, so that the maximum values permissible there are reliably maintained.

The essence of the present invention relates to the described method for arranging and designing lens structures for generating overhead values. The invention is not limited to the generation of a special overhead light distribution.

The method should determine the position, dimensions and number of overhead elements. The light source itself and the reflector must be taken into account. Suitable light sources are halogen and gas discharge lamps and semiconductor light sources in question. Preferred positions of the overhead structures are areas on the lens which are traversed by light which serves to generate the bright-dark boundary.

The surface structures of the invention can with the known lens structures (wave structures, scar patterns, diamonds after DE 10 2008 023 551 ), in particular those for influencing the light-dark boundary are combined. When using different structures on one lens surface, the structures for generating the overhead values are not overlaid with the other structures. Instead, the overhead structures described here are retained and the other structures are cropped accordingly.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009020593 A1 [0002, 0055]
• DE 102004024107 A1 [0010, 0012]
• DE 10309434 [0010]
• US 7040789 B2 [0010]
• US 7025483 B2 [0010]
• DE 202005004080 [0011]
• DE 102009020593 [0012]
• DE 4031352 A1 [0013]
• DE 9000395 U [0013]
• US 5307247 [0014]
• KR 1020090064724A [0015]
• KR 1020100069471 A [0015]
• DE 102008023551 [0079]

Cited non-patent literature

• Automotive Handbook, 24th Edition, April 2002, ISBN 3-528-13876-9, page 816 [0005]

Claims (19)

Method for arranging and dimensioning geometric overhead elements ( 34 ), which are called local deformations of an interface ( 32 ) of a projection lens ( 26 ) of a motor vehicle projection headlamp ( 10 ), which is adapted to project an edge which limits a luminous flux of a light source of the headlamp, as a cut-off line of a light distribution generated by the headlamp in its apron, wherein the overhead elements ( 34 ) are arranged to direct light into an overhead region of the light distribution which lies above the cut-off line, characterized in that in a first step partial regions ( 54 . 56 . 58 ) of the interface ( 26 ), that in a second step, overhead elements ( 34 ), which are arranged in the sub-areas defined in the first step, simulating an overhead illumination resulting from the simulated overhead elements, wherein the simulation of the defined overhead elements is used to define a number and / or shape of the defined overhead Iteratively to change overhead elements such that the simulated overhead illumination satisfies predetermined conditions. A method according to claim 1, characterized in that in the first step subregions are defined on the interface of the projection lens, which are suitable for the positioning of overhead elements, wherein the suitability results from the fact that the subregions have the smallest possible dimensions and that Luminous flux, which passes through these subregions, can be deflected without disturbing effects on the rest of the light distribution in the above the cut-off line overhead overhead area of the light distribution. A method according to claim 2, characterized in that portions are areas on the projection lens, which are traversed by light, which would serve in the absence of overhead elements for generating the cut-off line. Method according to one of the preceding claims, characterized in that in the first step, the interface of the projection lens is decomposed into small segments and that these segments are specifically examined for their suitability for the positioning of overhead elements. Method according to one of the preceding claims, characterized in that three subregions are defined, wherein two of the three subregions are arranged symmetrically to a plane containing the optical axis of the headlamp and perpendicular to the horizon and the optical axis and thus vertically aligned imaginary plane when the headlamp is aligned so as to produce a light distribution with a rule-conforming, at least partially parallel to the horizon lying light-dark boundary, and that the third region is arranged in such an orientation in a lower half of the interface, that it from the vertically oriented imaginary plane is divided into two equal halves. A method according to claim 5, characterized in that the two laterally symmetrically arranged subregions are rotated about an axis parallel to the optical axis and passing through the respective sub-axis of rotation so that they light in the described in claim 5 alignment of the headlight not only after above, but also to the side. Method according to one of the preceding claims, characterized in that for the defined overhead elements such geometries are used, which are characterized by a far reaching adaptability and whose effect on the light distribution can be simulated with good accuracy. A method according to claim 7, characterized in that the overhead elements are defined so that the boundary surface of the overhead elements to the air continuously differentiable merges into the not belonging to the overhead element adjacent interface of the projection lens. Method according to Claim 6, characterized in that the overhead elements to be arranged in the partial areas are defined with regard to their size, their number, their geometric design and orientation within the partial areas. A method according to claim 9, characterized in that thereby smaller surface portions of the light exit interface of the projection lens are tilted relative to their previous orientation so that they deflect the light passing through them in the above alignment of the headlight upwards. A method according to claim 10, characterized in that the angle of tilting is varied within the tilted surface portions in order to illuminate the entire overhead area with different degrees of upward deflected light. Method according to Claim 11, characterized in that one to ten overhead elements are used per subarea. Method according to claim 13, characterized in that the overhead elements are 0.02 to 0.2 mm far from them protrude or protrude from the surrounding boundary surface of the projection lens. Motor vehicle projection headlamp, which is adapted to project an edge which limits a luminous flux of a light source of the headlamp, as a cut-off of a light distribution generated by the headlamp in the apron, and which has a projection lens with geometric overhead elements, the are realized as local deformations of an interface of the projection lens and which are adapted to direct light in a light-dark-border overhead overhead area of the light distribution, characterized in that the overhead elements are limited to three subregions of the interface wherein two of the three portions are arranged symmetrically to a plane containing the optical axis of the headlamp and perpendicular to the horizon and to the optical axis and thus vertically aligned imaginary plane, when the headlamp is aligned so that it is a light distribution with a rule conform, at least t is partially parallel to the horizon lying light-dark boundary generated, and that the third region in such an orientation in a lower half of the interface is arranged so that it is divided by the vertically oriented imaginary plane into two equal halves. Headlamp according to claim 14, characterized in that the two laterally symmetrically arranged subregions are arranged around a respective axis parallel to the optical axis and passing through the respective sub-axis of rotation so twisted that they light in the described in claim 14 alignment of the headlight not only to the top, but also to the side. Headlamp according to claim 15, characterized in that the interface of the overhead elements to the air continuously differentiable merges into the adjacent surface of the non-overhead element belonging to the interface of the projection lens. A method according to claim 11, characterized in that each subregion has one to ten overhead elements. A method according to claim 17, characterized in that the overhead elements protrude 0.02 to 0.2 mm far from the surrounding boundary surface of the projection lens or projecting. Headlamp according to one of claims 14 to 17, characterized in that the interface in addition to the overhead elements has surface structures that do not serve to generate an overhead illumination and the outside of the overhead elements having portions of the interface are arranged.

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