EP1554521B1 - Led projector for asymmetrical illumination - Google Patents

Abstract

The invention relates to a novel projector which has an asymmetrical illumination characteristic, and a clear light-dark limit, and uses almost the entire radiation power outputted from the semiconductor light source. To this end, the projector consists of a field of individual semiconductor light sources which are provided with optical elements having a novel form. Said optical elements have as flat a form as possible, such that the light admission inlet of the optical element has an elongated, essentially rectangular form. Furthermore, the optical elements comprise a central region, perpendicular to the light admission surface (F), the projection of said central region into a two-dimensional plane corresponding to a cylindrical two-dimensional cartesian oval. According to the invention, in order to better use the light emitted from the semiconductor light source, the light emergence surface (G) of the optical element, in the form of a cartesian oval, is combined with a parabolic reflector (A, B).

Description

The invention relates to an LED headlamp which has an asymmetrical illumination characteristic and a method for operating such a headlamp according to the preamble of claims 1 and 10.

Driving a vehicle in traffic is a demanding, highly dynamic task. It places considerable demands on visual perception, cognitive processing and motor coordination of the driver. There is a general consensus in the literature that about 90 percent of information relevant to road traffic is absorbed by the sense of sight. Accordingly, it is important to have a good illumination of the traffic area at twilight and in darkness and in weather situations in which the natural light is insufficient. The currently valid ECE regulations for asymmetric low beam on European roads represent a compromise between good visibility and the least possible obstruction of other road users. A vehicle headlamp should be designed so that it shapes the light emitted by it so that as a result of the superposition the exiting light creates a prescribed for vehicle headlights light distribution; In particular, the formation of a clear bright-dark border and an asymmetrical characteristic of the illumination to avoid the glare of oncoming traffic is necessary.

The publication US 2001/019486 A1 also discloses a headlight comprising a field of individual radiator elements based on semiconductor light sources. In this case, it is possible in each case to control a plurality of the individual radiators in groups so as to radiate light specifically into predefined spatial areas. By suitable interconnection of individual emitters so the lighting characteristics of the headlight can be controlled.

The illumination system described in US Pat. No. 6,144,158 A, by employing a field of semiconductor lasers or alternatively a deflection device for the light beam of a single semiconductor laser, produces an illumination characteristic which has the clear light-dark boundary required in road traffic and an asymmetrical characteristic. However, the use of a laser light source which is necessary for the light bundling and which is less robust and expensive than shaking, has a disadvantageous effect on the possibilities of economically feasible realization.

A realized on the basis of cost-effective LED light sources headlight is known from the document DE 100 05 795 A1. In this case, a variable in its luminous characteristic headlight, realized by a field of individual emitters with at least one arranged in front of each individual emitter optics. Each of these optics can be moved in relation to the individual elements in all three spatial directions in order to influence the respective light beam emitted by the individual light element. In this way, variable control of the beam emitted by the headlight can be achieved.

Due to the typical for the related LED optics, a large opening angle having rotationally symmetric light distribution but can not create the rules of road traffic and a clear light-dark boundary having light distribution.

The object of the invention is therefore to find an inexpensive to manufacture lighting device which has an asymmetric lighting characteristic, which at the same time has a clear bright-dark boundary and thereby exploits as possible the entire output from the semiconductor light source radiation power.

The object is achieved by a lighting device and a method for operating such a device suitable method having the features of claims 1 and 10. Advantageous embodiments and further developments of the invention are shown by the subordinate claims. The invention will be explained in detail below with reference to embodiments and figures.

The illumination optics is formed by a field (array) of single optics. Here, the individual optics are designed as flat as possible in an inventive manner, so that the light entrance opening of the optics has an elongated, substantially rectangular shape. In this case, each individual optics has a central region perpendicular to the light entry surface, the projection of which in a two-dimensional plane corresponds to a cylindrical 2-dimensional cartoval. A kartoval is a geometric surface which, as the interface of a refractive medium, collects the light emanating from one focal point, even for large aperture angles in a second focal point. In order to make better use of the light emanating from the semiconductor light source, in the context of the invention the light exit surface of the optic formed in the form of a Kartoval is combined with a parabolic reflector.

Figur 1

zeigt die der Brechung an der Lichtaustrittsfläche der Optik zugrunde liegende Strahlengeometrie.

Figur 2

stellt die aus der Berechnung resultierende Konturlinie eines Kartovals dar.

Figur 3

repräsentiert den von einer Punktquelle ausgehende Strahlengang und zeigt den aus der Geometrie der Optik resultierenden Grenzwinkel der Reflektion auf.

Figur 4

zeigt eine 3-dimensionale Ansicht einer erfindungsgemäßen Optik.

Figur 4a

bildet die in Figur 4 gezeigte Optik als 3-dimensionales Kantenbild in vier unterschiedlichen Ansichten ab.

Figur 5

zeigt eine Querschnitt durch die erfindungsgemäße Optik mit der notwendigen Anpassung des parabolischen Kontur des Reflektors.

Figur 6

zeigt die Energieverteilung des aus der erfindungsgemäßen Optik austretenden Lichtes.

Figur 7

zeigt schematisch den Teil einer alternativen Ausführungsform der Optik auf Basis eines ,compund parabolic reflector'.

Figur 8

zeigt schematisch eine weiter alternative Ausführungsform der Optik (mit Blick auf die Lichteintrittsfläche), mittels welcher der von der Optik ausgehende Lichtkegel gezielt gekrümmt werden kann.

Figur 9

zeigt die Energieverteilung einer alternativen Optik entsprechend Figur 8.

Figur 10

beschreibt die Positionierung von Halbleiterlichtquellen an der erfindungsgemäßen Optik

In the following, the advantageous embodiments of the invention will be discussed in detail by means of figures and based on the mathematical derivation of the geometry of the optical system according to the invention. Here, starting from an advantageous use of the optics within headlamps, only the case is considered that the second focal point, in which the light beams emanating from the light source coincide, lies at infinity, ie the beam is converted into a parallel beam. In this way, the mathematical Treatment of the system greatly simplified. Further figures serve to explain in detail the advantageous embodiments and further developments of the invention.

FIG. 1

shows the beam geometry underlying the refraction at the light exit surface of the optics.

FIG. 2

represents the contour line of a Kartoval resulting from the calculation.

FIG. 3

represents the beam path emanating from a point source and shows the limit angle of the reflection resulting from the geometry of the optics.

FIG. 4

shows a 3-dimensional view of an optical system according to the invention.

FIG. 4a

forms the optics shown in Figure 4 as a 3-dimensional edge image in four different views.

FIG. 5

shows a cross section through the optical system according to the invention with the necessary adjustment of the parabolic contour of the reflector.

FIG. 6

shows the energy distribution of the light emerging from the optical system according to the invention.

FIG. 7

schematically shows the part of an alternative embodiment of the optics based on a 'compund parabolic reflector'.

FIG. 8

schematically shows a further alternative embodiment of the optics (with a view of the light entry surface), by means of which the light cone emanating from the optics can be purposefully curved.

FIG. 9

shows the energy distribution of an alternative optics according to FIG. 8.

FIG. 10

describes the positioning of semiconductor light sources on the optics according to the invention

ϕ ist dabei der Polarkoordinatenwinkel, α der Austrittswinkel aus dem brechenden Medium und β der Einfallswinkel im Medium. Nach dem Brechungsgesetz gilt: $$\frac{\sin \alpha }{\sin \beta }=n$$

In the following, the mathematical derivation of the contour curve is shown to illustrate the shape of a Kartoval. FIG. 1 shows the beam geometry on which the calculation is based. In this case, starting from a light source 60 schematically two light beams 20 and 21 are shown. Light beam 20 is intended here to represent that light which emerges perpendicularly from the light source 60 without refraction at the edge 10 of the optical system from its light exit surface. Light beam 21, however, exits at an angle φ from the semiconductor light source and impinges on the inside of the wall 10 at an angle dφ against the normal. For this reason, the light beam 21 is refracted and exits at an angle α from the optics at the light exit surface. Since the wall 10 has the contour of a Kartoval in an inventive manner, the light beam 21 is deflected in such a way that it runs parallel to the unbroken light beam 20 after exiting the optics. The relationship follows from this geometry of the beam square shown in FIG $$\alpha -\beta =\phi$$

φ is the polar coordinate angle, α is the exit angle from the refractive medium, and β is the angle of incidence in the medium. After the refraction law applies: $$\frac{\sin \alpha }{\sin \beta }=n$$

und daraus berechnet sich die gesuchte Funktion: $$\beta =\arctan \frac{\sin \varphi }{n-\cos \varphi }$$

First, the required angle of incidence β is calculated as a function of φ in order to let the light emerge in parallel from the element. From (1.1) and (1.2) follows: $$\frac{\sin \left(\phi +\beta \right)}{\sin \beta }=n$$

and from this the required function is calculated: $$\beta =\arctan \frac{\sin \phi }{n-\cos \phi }$$

This function indicates the angle of incidence β as a function of the polar coordinate angle φ. In the next step, the contour is calculated. From Figure 1 follows $$\frac{dr}{d\phi }=r\cdot \tan \beta$$

With G1. (1.4) the differential equation follows from this $$\frac{dr}{r}=\frac{\sin \phi }{n-\cos \phi }d\phi$$

This equation can be solved in an analytic form by substitution: $$\frac{r}{r_0}=\frac{n-\cos {\phi }_0}{n-\cos \phi }$$

This is the sought equation in polar coordinates of the contour line 11 of the Kartovals shown in Figure 2. Here, r ₀ is the radius associated with the angle φ ₀ , which serves to determine the absolute dimension of the contour. Of course, the equation 1.7 described in polar coordinates can be used. into the Cartesian coordinate system, resulting in equation (1.8) below: $$\frac{{\left(n+1\right)}^2}{n^2\cdot r_0^2}\cdot {\left(x-\frac{r_0}{n+1}\right)}^2+\frac{\left(n+1\right)}{\left(n-1\right)\cdot r_{\left(0\right)}^2}\cdot y^2=1$$

und der Grenzwinkel ϕ _g =90°-β. Für n=1,5 ergibt sich somit ein Grenzwinkel von 48,2°. Strahlung, die außerhalb dieses Öffnungswinkels liegt, kann mit diesem Element nicht sinnvoll ausgenutzt werden. Da Halbleiterlichtquellen in der Regel in einen weitaus größeren Winkelbereich emittieren, geht mit solchen Elementen ein großer Teil des Lichts verloren. Deshalb wird zur Umgehung dieser Problematik im Rahmen der Erfindung die im wesentlichen die Form eines zweidimensionalen Kartovals aufweisende Beleuchtungsoptik mit einem parabelförmigen Reflektor kombiniert. Dieser Reflektor sollte ebenfalls die Eigenschaft aufweisen, dass von dem Brennpunkt ausgehende Licht in ein paralleles Bündel zu wandeln. Dies führt zu dem in Figur 4 dargestellten Element, mit den Seitenflächen A,B und E und der Lichteintrittsfläche F. Wie aus Figur 4 ersichtlich, ist die erfinderische Optik recht flach ausgeführt, wobei die Lichteintrittsöffnung F einen im wesentlichen rechteckigen Querschnitt aufweist, wobei eine Dimension des Querschnitts wesentlich kleiner ist, als die andere; wie nachfolgend anhand von Figur 10 noch erläutert, ist wird der rechteckige Querschnitt in vorteilhafter Weise so schmal ausgeführt, dass gerade noch eine Halbleiterlichtquelle 60 an der Optik vollflächig angebracht werden kann. Zum besseren Klarstellung der 3-dimensionalen Ausgestaltung der in Figur 4 dargestellten erfinderischen Optik ist ein 3-dimensionales Kantenbild dieser Optik in vier unterschiedlichen Ansichten in Figur 4a abgebildet. Dabei heben die dortigen Abbildungen vor allem die Kanten der Optik, so wie in schraffierter Form die Seitenflächen A, B und 10 (Lichtaustrittsöffnung) hervor.An optic which has an exit surface in the form of a according to equation 1.8. However, the light of a point source can only parallelize in a limited angular range. This angular range is given by the limit of total reflection. FIG. 3 shows the beam path of the light beams 21a-d for a point source 60 and the resulting critical angle φ _g . By the contour of the light exit surface of the optics in the form of a Kartovals is achieved that all within twice the critical angle φ _g emerging from the light source 60 light beams 21a-d and 22 emerge in parallel from the optics. The critical angle φ _g is given by the refraction law (1.2), wherein the exit angle α = 90 °. This will be $\sin \beta =\frac{1}{n}$

and the critical angle φ _g = 90 ° -β. For n = 1.5, this results in a critical angle of 48.2 °. Radiation that is outside of this opening angle can not be meaningfully exploited with this element. Since semiconductor light sources usually emit in a much larger angular range, with such elements a large part of the light is lost. Therefore, in order to circumvent this problem in the context of the invention, the illumination optics, which essentially have the shape of a two-dimensional Kartoval, are combined with a parabolic reflector. This reflector should also have the property of converting the light emanating from the focal point into a parallel bundle. This leads to the element shown in Figure 4, with the side surfaces A, B and E and the light entrance surface F. As shown in Figure 4, the inventive optics is made quite flat, wherein the light entrance opening F has a substantially rectangular cross section, wherein a Dimension of the cross-section is substantially smaller than the other; as will be explained below with reference to Figure 10, is the rectangular cross-section is advantageously made so narrow that just a semiconductor light source 60 can be attached to the entire surface of the optics. For a better clarification of the 3-dimensional configuration of the inventive optical system illustrated in FIG. 4, a 3-dimensional edge image of this optical system is depicted in four different views in FIG. 4 a. Here, the illustrations above all emphasize the edges of the optics, as shown in hatched form the side surfaces A, B and 10 (light exit opening).

In a particularly advantageous manner, it is conceivable either to mirror the outer surfaces A and B of the parabolic reflector or to make it totally reflective. As a result, the best possible light output of the semiconductor light source is achieved, since approximately the entire light emitted by the light source is converted into a common parallel beam.

FIG. 5 shows the projection of the side face E of the optics according to the invention, in which case the contour of the kartoval shaped central region and of the parabolic reflector adjoining the outside thereof clearly appears. Ideally, the reflector is now designed so that at the corresponding to the surfaces C and D regions 40a and 40b of the contour at the light exit of the beam 23a refraction takes place in such a way that the emerging from the optics beams 23a and 21 run parallel. The course of the light beam 23a should thereby be influenced by turning the parabolic contour 41a corresponding to the outer surfaces A and B of the optics in the direction towards 41b. For this purpose, the parabola contour 41 is to be rotated inwards by the necessary angle in order to avoid that a light beam 23x emerges from the optics, which does not run parallel to the other parallel beam.

In the inventive embodiment of the optics of the illumination system, the deflection and alignment of the light takes place predominantly in a vertical plane, that is, the light is focused into a horizontally extending strip. FIG. 6 shows as a result of a calculation the energy distribution of the light emerging from the optical system according to the invention. In the upper part of the figure is shown in false color representation of the intensity profile of the outgoing light from a horizontally arranged optics. Alongside and below, the intensity distribution in the x-direction and the y-direction is shown in the form of a curve. It is thus clear that the light beam emerging from the optics is strongly bundled in the y-direction. Also in the x-direction, the light intensity emitted by the optics is clearly localized. In the simulation underlying FIG. 6, it was assumed that the light source is arranged centrally with respect to the light entry surface F of the optics, as explained in detail later, but it is also conceivable to install the light source at a different position on the light entry surface F in order to thereby specifically to influence lighting characteristics of the optics.

wobei a1 und a2 den jeweiligen Winkelbereich beschreiben, innerhalb dessen die Lichtstrahlen (25, 26) durch die Optik aufgenommen, beziehungsweise unter welchen diese dann aus die Optik austreten. Aus der Gleichung (1.8) ergibt sich, dass durch eine Vergrößerung der Austrittsfläche der Winkelbereich, in den das Licht emittiert wird, verkleinert wird. In besonders gewinnbringender Weise bietet es sich an auch in Strahlrichtung einen möglichst großen Akzeptanzwinkel zu schaffen, um optische Verluste zu vermeiden. Dies kann entweder durch Verspiegelung erreicht werden oder durch die entsprechende Gestaltung der Krümmung der Seitenflächen E, so dass dort Totalreflexion entsteht. In Figur 7 ist beispielhaft mit gestrichelter Linie der Krümmungsverlauf der Seitenfläche E für eine parabolische Krümmung angedeutet. Entsprechend der oben beschriebenen und auch in Figur 5 dargestellten Vorgehensweise kann an einem solchermaßen geformten kartovalen Zentralbereich erfindungsgemäß ein geeigneter parabolisch geformter Reflektor, zur optimalen Ausnutzung der von des von der Lichtquelle emittierten Lichts, angepasst werden.In a particularly advantageous manner, the horizontal width of the light spot can be influenced by tilting the side surfaces E of the optics in such a way that the optic tapers from the light exit surface G towards the light entry surface F. A corresponding geometry is shown in Figure 7, which shows a side view from the direction of the side surface A and B respectively. It is clear that in this profitable embodiment of the invention, the height extent F _{l of} the light entrance surface F of the optics smaller as the height extent G _l whose light exit surface 10 is. Such elements, especially with parabolic side surfaces are known from solar technology (CPC, Compound Parabolic Concentrator). The relationship applies: $$\frac{\mathrm{<figure-callout\; id="1"\; label="sin\; \alpha "\; filenames="imgf0006.png"\; state="\{\{state\}\}">sin\; </figure-callout>}\alpha 1}{\sin \alpha 2}=\frac{K_l}{F_l}$$

where a1 and a2 describe the respective angular range within which the light beams (25, 26) are received by the optics, or under which these then emerge from the optics. From the equation (1.8), it follows that enlarging the exit surface reduces the angular range in which the light is emitted. In a particularly profitable manner, it is also possible to create the greatest possible acceptance angle in the beam direction in order to avoid optical losses. This can be achieved either by mirroring or by the corresponding design of the curvature of the side surfaces E, so that there total reflection occurs. In FIG. 7, by way of example, the curved course of the side face E for a parabolic curvature is indicated by a dashed line. According to the procedure described above and also shown in FIG. 5, according to the invention a suitably parabolically shaped reflector for optimal utilization of the light emitted by the light source can be adapted to a cartouched central region formed in this way.

In a further advantageous embodiment of the inventive optical system, the cross-section whose light entry surface F deviates from the generally rectangular shape has a trapezoidal shape, as shown in FIG. The side surfaces of this trapezoidal shape are inclined by the angle α and β relative to the horizontal. It is conceivable that the two inclination angles α and β in their amount equal or to choose different from each other. Corresponding to the illustrations in FIG. 6, FIG. 9 shows the result of a calculation of the energy distribution of the light emerging from the advantageous optic with inclined side surfaces. In the calculation, the inclination angles α and β were set to 5 ° and 7 °, respectively. In the upper part of the figure, the intensity profile of the light emerging from a substantially vertically arranged optical system is again shown in false color representation. Alongside and underneath, the intensity distribution at specific positions in the x-direction and y-direction is shown in the form of a curve. As can be clearly seen from the figure, the radiation characteristic of the optics in the far field, contrary to the case shown in Figure 6, a significant curvature perpendicular to the radiation direction. On the other hand, this radiation characteristic also shows a clear light / dark transition. In this simulation as well, it was assumed that the light source is centered with respect to the light entrance surface F of the optics.

10 shows the projection of the light entry surface F of the inventive optical system, in this case with a rectangular cross section, with a semiconductor light source 60 adjoining centrally in the middle. In the general case, the semiconductor light source 60 is applied centrally on the light entry surface as shown in FIG. In this case, the thickness dimension of the optics is selected in a profitable manner so that it exceeds the dimensions of the semiconductor light source 60 as little as possible. In this way, optics with optimally small footprint, whereby it is possible to accommodate a variety of optics within a lighting source according to the invention in a small space and thus to achieve maximum light output.

By moving the semiconductor light source 60 along the connecting line between the points P1 and P2, it is achieved that the light from the optics emerges asymmetrically. It is conceivable either to position the semiconductor light source 60 fixedly at an arbitrary position along this connecting line, in order to achieve the desired asymmetrical radiation characteristic, or to arrange the optic slidably over the semiconductor light source 60, so that the desired asymmetry of the light emission by suitable displacement of the optics can be achieved with respect to the semiconductor light source 60. Alternatively, it is also conceivable to arrange a plurality of semiconductor light sources at the light entry surface F of the individual optics along the connecting line between P1 and P2 instead of a displaceable optic. Thus, the light emerging from the optics can be changed in its luminous characteristic advantageously without mechanical adjustment, simply by selective electrical control and selection.

In the arrangement of the optics to the illumination device according to the invention, it is conceivable in an advantageous manner individually to arrange the individual semiconductor light sources 60 to the respective optics arranged in a field so that the illumination device has an asymmetric radiation characteristic. Additionally or alternatively, however, it is also conceivable to achieve the asymmetrical radiation characteristic by arranging custom-shaped optics adapted to the desired light emission; in this case, it is conceivable that part of the optics having a rectangular light entrance surface F (corresponding to FIG. 10) and another part of the optics to perform with trapezoidal light entry surfaces F (corresponding to Figure 8). Also, in a profitable manner, the optics at least in part accordingly be executed the embodiment shown in Figure 7.

If at least some of the individual optics within the illumination device are assigned to a plurality of semiconductor light sources, pivoting of the illuminated cone emitted by the device or, in general, a change in the asymmetrical illumination properties of the illumination device can be effected by one of the plurality of optics associated with each Semiconductor light sources is driven. Such alternating activation of the light sources mounted on a single optics leads to the same beam pivoting as is the case in the prior art for displaceably arranged lens optics, without, however, having to resort to a prone, less robust mechanism. Furthermore, this advantageous embodiment also offers the possibility of individually controlling the individual optics within a group of optics without any outlay; this is not economically viable in the case of a mechanically variable deflection device.

Particularly profitable, the lighting device is designed so that the semiconductor light sources independently of the other individually or in groups can be controlled dimmed or activated or deactivated to light targeted and situation adapted to the environment can.

In a particularly advantageous manner, the inventive lighting device is suitable for use as a headlight in a motor vehicle to illuminate the environment in front of the vehicle asymmetrically.

Advantageously, when used in a motor vehicle, the individual optics associated with the headlamp are aligned with respect to the road surface such that the x-axes of the optics are substantially parallel thereto; i.e. the individual optics should be arranged essentially vertically (corresponding to, for example, FIG. 4).

Claims (13)

1. Illumination device, in particular for use in a motor vehicle, which is formed by an array of individual optical elements that are in each case assigned at least one semiconductor light source, in particular a light emitting diode,
   the optical elements having, perpendicular to the light entry area, a central region whose projection into a two-dimensional plane corresponds to a geometrical area, which, as an interface of a refractive medium, collects the light emerging from a focal point at a second focal point even for large aperture angles,
   characterized
   in that the light entry opening (F) of the optical elements have an elongate, essentially rectangular form,
   and in that said central region is combined with a parabolic reflector.
2. Illumination device according to Claim 1,
   characterized
   in that the outer areas A and B of the reflector are rotated in the direction of the central region of the optical element such that all beams emerging from the optical element are substantially parallel.
3. Illumination device according to either of Claims 1 and 2,
   characterized
   in that the outer areas A and B of the reflector are embodied such that they are mirror-coated or totally reflective.
4. Illumination device as claimed in one of the preceding claims,
   characterized
   in that the side areas E of the optical element are inclined in such a way that the optical element tapers from the light exit area G towards the light entry area F.
5. Illumination device as claimed in Claim 4,
   characterized
   in that the side areas are formed, in particular by means of mirror-coating or curvature, such that a large acceptance angle is produced in the beam direction.
6. The illumination device as claimed in one of the preceding claims,
   characterized
   in that the light entry area of the individual optical elements has a trapezoidal form.
7. Illumination device as claimed in one of the preceding claims,
   characterized
   in that at least one of the individual optical elements is assigned a plurality of semiconductor light sources.
8. Illumination device as claimed in one of the preceding claims,
   characterized
   in that the individual semiconductor light sources are switched individually.
9. Illumination device as claimed in one of the preceding claims,
   characterized
   in that the optical elements and the semiconductor light sources are arranged such that they are displaceable with respect to one another.
10. Method for driving an illumination device as claimed in one of the preceding claims,
    characterized
    in that the semiconductor light sources are driven individually in a manner dependent on the desired radiation characteristic,
    the semiconductor sources in this case being entirely or partly activated.
11. Method as claimed in Claim 10,
    characterized
    in that, for the case where a plurality of semiconductor light sources are assigned to an individual optical element, these are driven in a manner dependent on the desired radiation characteristic.
12. Method as claimed in either of Claims 10 and 11,
    characterized
    in that the lenses and the semiconductor light sources are displaced relative to one another for the purpose of changing the emission characteristic of the illumination device.
13. Use of the illumination device as claimed in one of the preceding claims as a motor vehicle headlight for asymmetrical illumination of the surroundings in front of a motor vehicle.

Images