EP3550203B1 - Light module for a swept-back motor vehicle lighting device - Google Patents

Description

The invention relates to a partial light module for a motor vehicle lighting device, comprising a planar, for example only very slightly curved or planar, illuminant which, for example, comprises a plurality of light sources, and a free-form lens, which free-form lens has at least two optically effective surfaces - a light entry surface and a flat light exit surface , on which optically effective surfaces preferably essentially all of the light generated by the areal illuminant (approx. 85 to 100% of the total amount of light) is refracted and transmitted. This is to be understood by the person skilled in the art in such a way that the planar illuminant and the light entry surface of the free-form lens are in a relative position and at a relative distance from one another, so that essentially the entire luminous flux emitted by the planar illuminant flows through the free-form lens. The above-mentioned conditions for the luminous flux are sufficient for the person skilled in the art to determine their relative position and relative distance from one another for a given (e.g. characterized by a luminance) the planar illuminant and geometry of the light entry surface. The person skilled in the art can, for example, use the basic photometric law or other generally known methods in order to deduce a suitable selection of the focal length of the free-form lens and the distance between the planar illuminant and the free-form lens.

In addition, the invention relates to a motor vehicle lighting device comprising at least two partial light modules of the type mentioned above.

Furthermore, the invention relates to a motor vehicle headlight comprising at least one such motor vehicle lighting device.

In motor vehicle lighting devices known from the prior art, lenses of the partial light modules are designed in such a way that on the one hand a partial light distribution generated by the respective partial light module has at least one symmetry with respect to the optical axis of the partial light module, and on the other hand a light exit surface of each part -Light module is normal to the optical axis of the corresponding partial light module. Each partial light distribution is often symmetrical with respect to a vertical plane running through an optical axis of the light module (see e.g. DE 102006057731 A1 ). Since a reference axis of the light source coincides with the optical axis of the lens, for example in a typical, preferably direct imaging light module, the optical axis of the lens can be defined as the optical axis of the partial light module. The intensity of the light emitted by the partial light module is highest along this axis. A reference axis of a light source can be understood, for example, as a main emission direction of this light source. This definition of the reference axis can be particularly favorable for flat light sources, such as LED light sources, which are arranged on a circuit board, for example, because a light intensity distribution or light intensity distribution generated by the LED light source is symmetrical with respect to the main emission direction and the main emission direction is orthogonal to the light-emitting surface of the LED light source (Lambert's law). DE 10 2017 202 486 A1 discloses another partial light module for a motor vehicle lighting device.

In modern car construction, headlights (motor vehicle headlights) are adapted to the design of the motor vehicle. Body design surfaces, design lines and thus also the appearance and position of the motor vehicle headlights in a motor vehicle are specified. The position of the motor vehicle headlights plays a major role in the position of an overall light distribution (for example a low beam or a high beam distribution) generated with the motor vehicle headlights. Accordingly, the arrangement of the optical components in a motor vehicle headlight should be such that both design specifications and legal requirements and, last but not least, high customer-specific quality specifications for the overall light distribution generated can be met. The term arrow is known in motor vehicle construction, in particular with regard to the installation of light guides in motor vehicle headlights. This is the course of a front contour of a motor vehicle headlight, for example a design contour/arrow axis D (see Fig figures 1 and 2 ), or the course of its cover plate, in relation to the longitudinal axis of the vehicle (X in figures 1 and 2 ). This progression is mostly and also in connection with the present invention expressed by an angle (for example as an angle of inclination of the design contour/arrow axis to the longitudinal axis of the motor vehicle). The course of the design contour depends on the position, shape and dimensions of an installation opening for the motor vehicle headlight in the body or on the design of the motor vehicle body, in particular in an area around the motor vehicle headlight. In modern streamlined In automobiles, automobile headlights often recede to the outside of the automobile and up toward the hood. This results in a sometimes very pronounced sweep, which can reach values of up to 30° and even exceed them. This can lead to the above-mentioned difficulties when designing/installing the optically relevant components (e.g. light modules or partial light modules) in such "strongly swept" motor vehicle headlights, because, for example, in order to implement a main light function (low beam or high beam function), a light shines in Motor vehicle headlights emit light mainly in the direction of travel (along the longitudinal axis of the motor vehicle) in order to primarily illuminate an area in front of the motor vehicle. If you were to design the optically relevant components in a motor vehicle headlight without taking the sweep into account, it can happen that the light distribution emitted by this motor vehicle headlight is shifted with respect to the HV point or rotated horizontally when the motor vehicle headlight is installed in a motor vehicle and is tested, for example, with regard to the emitted light distribution in a lighting technology laboratory. Such a shifted or twisted light distribution would not be able to meet the legal requirements. The term "HV point" refers to the term, familiar to those skilled in the lighting arts, used to designate a point where the HH line (hh line or horizon) meets the VV line (vv line or vertical ) crosses on a measuring screen, which measuring screen is set up to measure a light distribution generated by any light module (usually in a motor vehicle lighting technology laboratory). Such a shift in the light distribution on the measuring screen can be proportional to the sweep. One approach known from the prior art to address the problem is that the optically relevant components - for example, partial light modules consisting of a light source and a lens upstream of this light source - are designed in a headlight in such a way that these partial light modules Emit light along the \ parallel to the longitudinal axis of the vehicle (see 1 ). The disadvantage of this solution is how figure 1 can be seen, which shows a plurality (five are shown, but preferably there are approx. 6 to 15) offset side-by-side partial light modules that crosstalk can occur between the individual partial light modules and, as a result, false light can occur, which ultimately reduces the quality of the generated light distribution. A further disadvantage is that the light sources, for example LED light sources, cannot be fixed in one plane, for example on a circuit board, which means, for example, more Space may be required. In addition, such a staggered arrangement may be undesirable for design reasons.

In some projection systems and/or free space reflection systems known from the prior art, the optical axis of the respective projection system and/or free space reflection system is aligned along the longitudinal axis of the motor vehicle. The front axle center/center point of the front axle of the motor vehicle is generally taken as the starting point for the longitudinal axis of the motor vehicle.

It is an object of the present invention to create a partial light module for a motor vehicle lighting device, which partial light module takes account of an arbitrarily strong sweep. This means that when partial light modules are used in a motor vehicle lighting device, the motor vehicle lighting device can emit a legally compliant overall light distribution without having to change the physical position of the partial light modules in the motor vehicle lighting device. In this case, in particular, the space requirement should also be kept low. “Arrowing of any degree” is to be understood as meaning an arrowing that is justifiable from a professional point of view within the framework of the motor vehicle construction sector (for example, a arrowing of more than 90° would make no sense). This object is solved with the features of claim 1.

At this point it should be noted that every light distribution can be described in the form of a cone - a symmetrical emission cone. The axis of such a symmetrical radiation cone usually coincides with its height and with the optical of the light system forming the light distribution.

In connection with the present invention, the term “decentered free-form lens” is understood to mean that free-form lens which is set up to generate a light distribution in the form of an emission cone, with the axis of the emission cone not running parallel to a predetermined direction. This means that the free-form lens according to the invention is designed in such a way that a radiation cone generated with the aid of the free-form lens has a radiation cone axis that does not run parallel to the reference axis and to the optical axis.

The expression “partial light module produces a partial light distribution” is often used in connection with the present application. It goes without saying that a partial light module only generates a partial light distribution when it is put into operation. A partial light module according to the present invention that has not been put into operation is set up to generate a partial light distribution.

The planar illuminant can include multiple light sources. The number of light sources preferably ranges from about 6 to 15 pieces. In connection with the present invention, the term planar lighting means is understood to mean a preferably essentially flat or only very slightly curved luminous surface. This luminous surface can be embodied, for example, as a light-emitting layer of an LED or an OLED or as a light conversion means, which is illuminated, for example, with laser light and glows due to light conversion. In this case, this surface generates the radiated light - the luminous image, which is projected directly in front of the partial light module using the free-form lens. However, the luminous surface can also transmit light from another light source and can be designed, for example, as a mirror, e.g. as a micromirror in a MEMS mirror.

The reference axis of the planar light source can, for example, coincide with the direction along which the radiant intensity generated by the planar light source is greatest or maximum. This is particularly useful in the case of the lighting means designed as LED light sources, because these represent a Lambertian emitter to a good approximation. In this case, it may be useful to define the reference axis as the direction in which the LED light source has maximum radiant intensity radiates, the reference axis defined in this way coinciding with an axis of symmetry of the light distribution generated by the LED light source.

In anticipation, it should be noted at this point that the optical axis of the free-form lens and the reference axis of the planar illuminant - also during the calculation process of the light entry surface of the free-form lens described below - coincide. Lateral shifting of the planar lighting means, preferably the LED light source(s) with respect to the free-form lens - also described below - can be 'tried out' at the end of the calculation process. This creates a slightly oblique bundle of rays, with the reference axis and the optical axis essentially retaining their parallel orientation.

The present invention makes use of the fact that the light distribution emitted by the planar illuminant in the direction of the free-form lens, for example symmetrical with respect to the reference axis, can be modified by designing the optically effective surfaces of the free-form lens - the light entry and light exit surfaces.

The shape of a light distribution modified by the free-form lens can be almost arbitrary. For example, by specifying a symmetrical and a modified light distribution, one can deduce how the one or more lens surfaces of the free-form lenses - i.e. their optically effective surfaces - should run so that the desired modified light distribution can be generated from the original, for example symmetrical, light distribution . For this purpose, special methods have been developed in the prior art. An example of such a method is in a at the Karlsruhe Institute of Technology submitted dissertation "Analytical design of free-form optics for point light sources" by Andre Domhardt (ISBN 978-3-7315-0054-4 ) described.

The inventive decentering of the free-form lens contributes, for example, to a light distribution (partial light distribution) generated with the partial light module appearing "shifted" in the light image with respect to a light distribution generated using a partial light module with a centered free-form lens. As a result, the sweep can be taken into account and compensation for the sweep of a motor vehicle can be made possible.

At this point it should be noted that the direction of displacement or rotation of the light distribution can be different, depending on the motor vehicle headlight in which the partial light module is used. In the case of left-hand and right-hand motor vehicle headlights, this direction is mirrored about a vertical plane running through the longitudinal axis of the vehicle.

An advantage of the present invention is therefore that a shift of the light image proportional to the sweep can be achieved in a motor vehicle lighting device, for example direct imaging, by decentering the free-form lenses of the partial light modules of the motor vehicle lighting device.

It can therefore be expedient if the planar light source is set up to generate light and the free-form lens is set up to project essentially all of the light in the form of a partial light distribution in front of the partial light module, with the light entry surface for the entry of the light in the free-form lens is provided and preferably faces a surface of the planar illuminant intended for emitting the light, and the planar light exit surface is provided for exiting the light from the free-form lens and the partial light distribution is designed as an emission cone, with at least the axis and/or height of the radiation cone does not coincide with the reference axis (and with the optical axis of the free-form lens aligned in the same way as the reference axis).

As already explained, light distributions can generally be represented as an emission cone. Free-form lenses according to the invention lead to this or are designed in such a way and/or arranged with regard to the planar light source in such a way that the partial light modules according to the invention generate partial light distributions which are designed as emission cones whose heights and/or axes correspond to the reference axes of the corresponding light sources (and the optical axes of the corresponding free-form lenses) do not coincide. As shown below, the partial light distributions can have their light center (highest values of light intensity, light intensity or similar) either along the height or along the axis of the emission cone or be brightest along the height or the axis. When the beam is symmetrical, its axis coincides with its height and the corresponding centroid of light is along the axis and height of the beam.

In connection with the present invention, both a three-dimensional light distribution—radiation cone—and a two-dimensional projection of the light distribution onto a vertical plane—the base of the radiation cone—are spoken of. The same term light distribution or partial light distribution is always used here. Which representation of the light distribution or the partial light distribution (3D or 2D) is meant here will be apparent to the person skilled in the art from the context.

It can be expedient here if the radiation cone has a horizontal opening angle of approximately 70° to approximately 80°, in particular approximately 75°, and a vertical opening angle of approximately 5° to approximately 10°.

In an embodiment proven in practice, it can be provided that the light entry surface of the free-form lens is designed in such a way that the free-form lens has a emission cone axis that encloses a decentration angle Φ (deviating from zero) with the reference axis. It goes without saying that a radiation cone can be assigned to each free-form lens. For this reason, each free-form lens can also be assigned an emission cone axis. In other words, each free-form lens can have an emission cone axis.

It can be advantageous if the freeform lens has a planar vertical side cut, which planar vertical side cut extends from the light entry surface to the light exit surface along the reference axis (or along the optical axis of the freeform lens), preferably in a direction parallel to the reference axis .

In addition, it can be advantageous if the free-form lens has an optical axis and a geometric axis that deviates from the optical axis and runs through the geometric center of the free-form lens, with the direction of its optical axis coinciding with the direction of the reference axis. In addition, the optical axis can coincide with the reference axis. The geometric axis preferably runs parallel to the optical axis. The geometric axis can be spaced horizontally from the optical axis, for example. By positioning the side trim, the geometric axis (i.e. parallel to the reference axis through the geometric center of the Axis running free-form lens) from/to the optical axis away/toward and thereby the sweeping into account. In addition, the height of the radiation cone can deviate from the axis of the radiation cone - skewed radiation cone. It can also be provided that the emission cone height of an oblique emission cone, for example, coincides with the reference axis and/or with the optical axis and/or with the geometric axis.

In addition, it is advantageous if the free-form lens has a minimum width, preferably dependent on the decentration, which minimum width is preferably between 25 mm and 45 mm, in particular 35 mm, and/or a focal length of approximately 15 mm to 22 mm and/or height from about 12 mm to 18 mm.

With regard to the design of the partial light distribution, it can be expedient if the light entry surface is flat, concave or convex in the horizontal direction and curved in the vertical direction, in particular is convex.

For example, in order to further increase a horizontal shift in the partial light distribution in the light image, it can be expedient if an optical structure is arranged on the planar light exit surface, which optical structure preferably comprises prismatic, sawtooth-shaped elevations, in particular prisms. The prismatic, sawtooth-shaped elevations, in particular prisms on the light exit side, serve to incline the emission cone axis of the free-form lens even more (preferably in the horizontal plane) with respect to its optical axis. If the emission cone axis coincides with the optical axis of the free-form lens, the prismatic, sawtooth-shaped elevations mean that the emission cone axis no longer coincides with the optical axis of the free-form lens.

In an embodiment that has proven itself in practice, it can be provided that the lighting means is in the form of an LED light source which, for example, comprises a plurality of LED chips can. The individual LED chips of the LED light source can be in the form of a printed circuit board equipped with one or more LEDs. The LEDs on the circuit board can be rectangular, for example, and preferably have a vertical edge length (the edge length of the light-emitting surface of the individual LED) of about 0.5 mm to 2 mm, in particular 0.7 mm to 1 mm.

In addition, provision can be made for additional optical attachments, for example collimator or focusing optics, to be arranged between the planar illuminant and the free-form lens. For example, exactly one such additional optical attachment can be placed in front of each LED. Such an attachment optic can be attached to the LED chip and generates, for example, a collimated or focused light beam. The numerical aperture changed as a result can serve as one of the basic parameters explained below in the method for constructing the partial light module.

In addition, it can be useful if the light entry surface of the free-form lens is at a distance from the light exit surface of the free-form lens. A medium which has a different refractive index than air is preferably arranged continuously between each light entry surface and the light exit surface corresponding to this light entry surface. Different media between the light entry surfaces and the light exit surfaces can influence the light-refracting properties of the free-form lens and the shift in the partial light distribution generated (in the light image). The free-form lenses can be designed as gradient lenses, for example.

It can be advantageous, for example with regard to the generation of an HD limit, if each vertical section of each light entry surface is of convex design.

It can be advantageous if each horizontal section of each light entry surface is rectilinear or convex. A stronger concentration of the light is achieved in the center of the illuminance maximum, which is usually at the HV point.

In order to generate a broad light distribution, it can be advantageous if each horizontal section of each light entry surface is straight or concave. The maximum illuminance just mentioned is distributed/smeared more strongly.

The object of the invention is also achieved according to the invention with a motor vehicle lighting device of the type mentioned at the outset in that it comprises at least two partial light modules.

It can advantageously be provided that the free-form lenses of different partial light modules are decentered differently.

It can be expedient if each partial light module is set up to generate a partial light distribution, with each partial light distribution being designed as a radiation cone, with at least the axis and/or height of the radiation cone being aligned with the reference axis (and with the with the Reference axis identically aligned optical axis of the free-form lens) does not coincide, and emission cone axes or emission cone heights are spaced apart from one another by predetermined distances h1, . . . , hn, preferably in the horizontal direction. It can be provided that the emission cone axes lie in a horizontal plane. The distances h1, . For example, these distances can be measured at the HH line - the horizontal line on the measuring screen corresponding to the horizon.

It can be expedient if the partial light distributions are superimposed at least in pairs and their superimposition preferably forms a total light distribution that preferably satisfies relevant legal standards, for example a front light distribution, in particular a homogeneous front light distribution.

A particularly attractive design can result from that arrangement if the light exit surfaces are arranged in a common plane, for example flush, are preferably lined up next to one another or arranged in the form of a matrix.

In addition, it can be provided that the planar light sources of the partial light modules in the motor vehicle lighting device are arranged in a row or in a matrix next to one another or adjacent to one another, with the row or the plane formed by a matrix arrangement extending along an arrow axis or a design contour who if who Motor vehicle lighting device is installed in a motor vehicle, the angle, preferably the sweep, includes the vehicle longitudinal axis.

In order to be able to take the legal standards into account, it can be expedient if the motor vehicle lighting device emits light in a first emission angle range from 0° to approx of the motor vehicle longitudinal axis and in a second beam angle range of 0° to approx. 25° on the other hand (corresponds to the extent of the light distribution on the inside of the motor vehicle if the motor vehicle lighting device is installed in a motor vehicle headlight in accordance with standards) with respect to the motor vehicle longitudinal axis.

Furthermore, the object of the invention is achieved according to the invention with a motor vehicle headlight of the above-mentioned type in that the motor vehicle headlight comprises at least one above-mentioned motor vehicle lighting device and a cover pane, the light exit surfaces being arranged in a common plane following the course of the cover pane.

• Schritt 1: Festlegen einer durch Mitte einer der Lichteintrittsfläche zugewandten Seite des flächenhaften Leuchtmittels verlaufenden und zu dieser Seite im Wesentlichen orthogonal stehenden Bezugsachse;
• Schritt 2: Ausgehend davon, dass die Bezugsachse mit der optischen Achse zusammenfällt, Festlegen der Grund-Parameter der Freiformlinse gemäß gesetzlichen Normen, Pfeilung und zumindest eines Größenparameters des flächenhaften Leuchtmittels;
• Schritt 3: Anhand der Grund-Parameter aus Schritt 2 und unter der, als eine Anfangsbedingung bei einer nachfolgenden Berechnung dienenden Annahme, dass das flächenhafte Leuchtmittel in einer Brennfläche der Freiformlinse angeordnet ist und die optische Achse mit der Bezugsachse zusammenfällt, Berechnen der Dezentrierung der Freiformlinse derart, dass das von dem flächenhaften Leuchtmittel erzeugte Licht mittels der Freiformlinse gemäß den gesetzlichen Normen und der Pfeilung in Form einer Teil-Lichtverteilung vor das Teil-Lichtmodul projiziert wird; (Als Ergebnis der Dezentrierung ergibt sich, dass die Abstrahlkegelachse und/oder die Abstrahlkegelhöhe zu der optischen Achse und zu der Bezugsachse nicht parallel verläuft).
• Schritt 4: Herstellen, beispielsweise durch Spritzgießen, einer Freiformlinse, die eine gemäß Schritt 3 berechnete Dezentrierung aufweist;
• Schritt 5: Anordnen der in Schritt 4 hergestellten Freiformlinse hinsichtlich des flächenhaften Leuchtmittels gemäß der gemäß Schritt 3 berechneten Dezentrierung.

Also disclosed is a method for constructing a partial light module for a motor vehicle lighting device according to a predetermined arrow shape, the partial light module comprising a planar illuminant and a free-form lens having an optical axis, which free-form lens has a light entry surface and a planar light exit surface. The procedure has the following steps:

• Step 1: defining a reference axis running through the center of a side of the planar illuminant facing the light entry surface and being essentially orthogonal to this side;
• Step 2: Based on the fact that the reference axis coincides with the optical axis, determination of the basic parameters of the free-form lens in accordance with legal standards, sweeping and at least one size parameter of the planar illuminant;
• Step 3: Using the basic parameters from step 2 and assuming, serving as an initial condition in a subsequent calculation, that the planar light source is arranged in a focal surface of the free-form lens and the optical axis coincides with the reference axis, calculating the decentration of the free-form lens such that the light generated by the planar light source by means of the free-form lens in accordance with the statutory standards and the arrow in the form of a partial light distribution the partial light module is projected; (The result of decentering is that the emission cone axis and/or the emission cone height is/are not parallel to the optical axis and to the reference axis).
• Step 4: producing, for example by injection moulding, a free-form lens having a decentering calculated according to step 3;
• Step 5: arranging the free-form lens produced in step 4 with respect to the planar illuminant according to the decentration calculated according to step 3.

• Schritt 2a: Festlegen eines Linsenmaterials, beispielsweise eines Brechungsindex.
• Schritt 2b: Festlegen eines Brennweite-Wertes (der Mindestschnittweite) der Freiformlinse mittels der Formel: $f_{\mathit{Linse}}=\frac{L_V}{\tan \left(\beta \right)}$
  
  , wobei L_v eine vertikale Kantenlänge des flächenhaften Leuchtmittels (3) ist, und β eine in Grad ausgedrückte Position/Lage einer Obergrenze einer Lichtverteilung, vorzugsweise der Teil-Lichtverteilung, ist. Die Lage dieser Obergrenze ist gesetzlich vorgeschrieben und kann den einschlägigen gesetzlichen Normen entnommen werden. Beispielsweise ist β = 4° laut ECE-Regelung beziehungsweise FMVSS-Vorgabe. "FMVSS" steht für Federal Motor Vehicle Safety Standards und ist in USA geltender Standard.
• Schritt 2c: Festlegen eines Mindestbreite-Wertes l_Linse der Freiformlinse in horizontaler Richtung gemäß der Formel: l_Linse = f_Linse ∗ tan( Δ + a), wobei Δ - gesetzlich vorgegebener Streuungswinkel und α eine vorgegebene Pfeilung ist.

It can be advantageous if the determination of the basic parameters of the free-form lens according to legal standards, sweeping and at least one size parameter of the planar illuminant also has the following steps:

• Step 2a: Determine a lens material, for example a refractive index.
• Step 2b: Set a focal length value (the minimum focal length) of the freeform lens using the formula: $f_{\mathit{lens}}=\frac{L_V}{\tan \left(\beta \right)}$
  
  , where L _v is a vertical edge length of the planar illuminant (3), and β is a position/position, expressed in degrees, of an upper limit of a light distribution, preferably the partial light distribution. The position of this upper limit is prescribed by law and can be found in the relevant legal standards. For example, β=4° according to the ECE regulation or FMVSS specification. "FMVSS" stands for Federal Motor Vehicle Safety Standards and is the standard in force in the USA.
• Step 2c: Determine a minimum width value l _lens of the free-form lens in the horizontal direction according to the formula: l _lens = f _lens * tan( Δ + a), where Δ - statutory divergence angle and α is a specified sweep.

In a practice-proven embodiment of the method, it can be provided that the decentering of the free-form lens is calculated in step 3 as follows:
Step 3a: Calculate an asymmetrical surface profile of the light entry surface such that the optical axis of the free-form lens has a predetermined decentration angle Φ as the reference axis with respect to the emission cone axis, the decentration angle Φ corresponding to the sweep, preferably being the same as the sweep.

In addition, it can advantageously be provided that the decentering of the free-form lens is calculated in step 3 as follows:
Step 3b: Calculation of a surface profile of the light entry surface that is symmetrical, for example with respect to a vertical plane running through the optical axis, and a planar vertical side cut of the freeform lens, which plane vertical side cut extends from the light entry surface to the light exit surface along a direction parallel to the optical axis , around a cropped free-form lens, that the free-form lens has an optical axis and a geometric axis running through the geometric center of the free-form lens, the geometric axis being shifted with respect to the optical axis by a distance corresponding to the sweep, preferably horizontally.

In addition, it can be advantageous if, in step 4, an additional optical structure is attached to the planar light exit surface of the free-form lens, for example by means of milling.

It may be useful if the procedure involves an additional
Step - Step 6 - the planar illuminant is shifted with respect to the free-form lens.

It is therefore possible to produce partial light modules whose optical structure has an intrinsic asymmetry. This asymmetry is produced by an asymmetrical design of a free-form lens provided in the partial light module. As already mentioned, such asymmetry can be achieved by decentering the free-form lens. In addition, it should be noted that in automotive construction, it is often not possible to use the light exit surface of the free-form lens to decenter the free-form lens. This is because the partial light modules arranged in a motor vehicle headlight are subject to a number of design requirements, for example. These often stipulate that the light exit surface, i.e. the surface of the free-form lens that faces outwards, i.e. the light-refracting surface of the free-form lens when the partial light module is installed in a motor vehicle headlight, should be planar or may have at most one optical structure, the structural elements of which are in the micro to several millimeters (e.g. 10 micrometers to 1 millimeter) may be large. This includes a design of the light exit surface as a free form to a considerable extent.

• Fig. 1 fünf herkömmliche Teil-Lichtmodule in Draufsicht, die stufenartig, horizontal zueinander versetzt in einen Kraftfahrzeugscheinwerfer eingebaut sind;
• Fig. 2 Teil-Lichtmodule gemäß der vorliegenden Erfindung in Draufsicht, die verdreht und aneinandergereiht in einen Kraftfahrzeugscheinwerfer eingebaut sind;
• Fig. 3 eine perspektivische Ansicht eines Teil-Lichtmoduls mit einer eine konkav-konvexe Lichteintrittsfläche aufweisenden Freiformlinse;
• Fig. 4 eine perspektivische Ansicht eines Teil-Lichtmoduls mit einer eine konvex-konvexe Lichteintrittsfläche aufweisenden Freiformlinse;
• Fig. 5 eine perspektivische Ansicht des Teil-Lichtmoduls der Figur 3, wobei die Lichtaustrittsfläche der Freiformlinse zusätzlich eine optische Struktur in Form von Erhebungen aufweist;
• Fig. 6 und Fig. 7 durch ein Teil-Lichtmodul gemäß erzeugte Teil-Lichtverteilungen in Form von Abstrahlkegeln;
• Fig. 8 eine perspektivische Ansicht eines Teil-Lichtmoduls;
• Fig. 9 eine durch ein Teil-Lichtmodul erzeugte Teil-Lichtverteilung in Form eines Abstrahlkegels;
• Fig. 10 Schnitt AA der Figur 8;
• Fig. 11 Schnitt BB der Figur 8;
• Fig. 12 einen Strahlengang in einem erfindungsgemäßen Teil-Lichtmodul;
• Fig. 13 ein Teil-Lichtmodul mit einer auf ihrer Lichtaustrittsfläche eine optische Struktur aufweisenden Freiformlinse;
• Fig. 14 ein Teil-Lichtmodul mit einer verschobenen LED-Lichtquelle;
• Fig. 15 ein Ablaufdiagramm eines erfindungsgemäßen Verfahrens;
• Fig. 16 ein Modell, insbesondere ein Computer-Modell, eines Teil-Lichtmoduls, und
• Fig. 17 und Fig. 18 in einem Kraftfahrzeug angeordnete, mehrere erfindungsgemäße Teil-Lichtmodul aufweisende Kraftfahrzeugscheinwerfer.

The invention is explained in more detail below using exemplary, non-limiting preferred embodiments, which are illustrated in a drawing. In this shows:

• 1 five conventional partial light modules in plan view, which are built into a motor vehicle headlight in steps, horizontally offset from one another;
• 2 Partial light modules according to the present invention in plan view, which are installed rotated and lined up in a motor vehicle headlight;
• 3 a perspective view of a partial light module with a free-form lens having a concave-convex light entry surface;
• 4 a perspective view of a partial light module with a convex-convex light entry surface having a free-form lens;
• figure 5 a perspective view of the partial light module figure 3 , wherein the light exit surface of the free-form lens additionally has an optical structure in the form of elevations;
• 6 and 7 partial light distributions in the form of emission cones produced by a partial light module according to FIG.
• 8 a perspective view of a partial light module;
• 9 a partial light distribution generated by a partial light module in the form of a radiation cone;
• 10 Section AA of the figure 8 ;
• 11 cut BB the figure 8 ;
• 12 a beam path in a partial light module according to the invention;
• 13 a partial light module with a free-form lens having an optical structure on its light exit surface;
• 14 a partial light module with a shifted LED light source;
• 15 a flowchart of a method according to the invention;
• 16 a model, in particular a computer model, of a partial light module, and
• 17 and 18 Motor vehicle headlights arranged in a motor vehicle and having a plurality of partial light modules according to the invention.

First up figure 1 Reference is made to FIG. 1, which schematically shows a left-hand motor vehicle headlight 1' with a prior art motor vehicle lighting device 2' in plan view. The standard motor vehicle lighting device 2' shown comprises five conventional partial light modules 3' (of a so-called direct-imaging projection type), which are installed in the motor vehicle headlight 1' in a step-like manner, horizontally offset from one another. Each partial light module 3' comprises an LED light source 4' and a lens 5', for example a free-form lens, arranged in front of this LED light source 4'. The lens 5 'is centered and has an optical axis 6', which runs with a, for example, geometric center of the LED light source 4 ', to a light-emitting / light-emitting plane of the LED light source 4' substantially perpendicular and the LED light source 4 'associated reference axis 7' coincides. In the arrangement shown here, each partial light module 3′ radiates a partial light distribution centered with respect to the optical axis 6′ and the reference axis 7′, ie a light distribution in the form of a straight line Has radiation cone. The emission cone axis (or main emission direction) 301' is the optical axis 6' of the lens 5'.

In a partial light module of the direct imaging projection type, a light image is generated using an optical projection system, for example a lens or a free-form lens, in that the projection system projects a luminous object (a luminous image, e.g. luminous surface of an LED ) directly - i.e. without creating an intermediate image, for example by means of reflectors.

The motor vehicle headlight 1' has an outer contour whose course D is inclined in many modern motor vehicles, and especially in passenger cars, with respect to a motor vehicle longitudinal axis X when the motor vehicle headlight 1' is installed in a motor vehicle (not shown here). This inclination corresponds to the so-called sweep, which can be expressed as the angle α between the course D of the outer contour of the motor vehicle headlight and a horizontal direction perpendicular to the longitudinal axis X of the motor vehicle (see Fig figure 1 ). Accordingly, the conventional partial light modules 3' are arranged in the motor vehicle headlight 1' in such a way that their optical axes 6' and the emission cone axes and heights associated with their free-form lenses are aligned parallel to the longitudinal axis X of the motor vehicle. In addition, in order to take account of the sweep and to emit a legally compliant light distribution, the conventional partial light modules 3' in the motor vehicle headlight 1' are arranged in steps, offset in the direction of the longitudinal axis X of the motor vehicle. However, such an arrangement is disadvantageous in many cases because, for example, there is crosstalk (the light from a partial light module reaches one or more adjacent partial light modules) between the individual partial light modules 3', resulting in unwanted scattered light and/or additional Lead "imaging errors" and, for example, the external appearance of the vehicle headlight (especially when it is turned on) can affect. The term aberration is intentionally provided with quotation marks, since it is not a question of classic aberrations of lenses, such as aberration, but of unwanted additional images of a luminous surface of the planar illuminant with other refracting surfaces of the free-form lens.

It goes without saying that both in figure 1 shown partial light modules 3 'or in the case of the motor vehicle headlight 1' according to the prior art, as well as further (not shown) optically relevant elements such as reflectors, screens, light guides etc. which enable the partial light modules and/or motor vehicle headlights to function properly.

figure 2 shows schematically a (left) motor vehicle headlight 1 with a light module 2, which corresponds to a motor vehicle lighting device according to the invention. The light module 2 can, like 2 shows be installed in the motor vehicle headlight 1. It goes without saying that the invention is not only designed for left-hand motor vehicle headlights but can also be used without further ado, for example in right-hand motor vehicle headlights. The light module 2 comprises several (here seven) sub-light modules 3, 30 (of the projection type) according to the present invention, which are twisted and arranged in a row. Each partial light module includes a (flat) LED light source 4, which can be formed, for example, from one or more (flat LEDs) that correspond to the planar illuminant, and a free-form lens 5, 50 arranged downstream of the (flat) LED light source in the light emission direction , wherein the LED light source 4 is arranged in an (object-side) focal surface (preferably focal plane) of the free-form lens 5, 50 and is imaged directly in front of the partial light module 3, 30 by the free-form lens 5, 50. The term “projection type” indicates that the light image generated by the partial light module 3, 30 is generated using a projection lens or—in the case of the present invention—a free-form lens 5, 50. The LEDs of the LED light source 4 can be arranged, for example, on a common circuit board 400, for example in a row or in the manner of a matrix (not shown).

The free-form lenses 5, 50 have flat light exit surfaces 52, 502. The partial light modules 3, 30 are preferably arranged in the light module 2 in such a way that the planar light exit surfaces 52, 502 of the free-form lenses 5, 50 lie essentially in one plane or in a slightly curved surface (i.e. insignificantly different from the course of a plane). This plane or slightly curved surface runs essentially parallel to a predetermined outer contour D of a cover plate of the motor vehicle headlight 1. The free-form lenses 5, 50 can be lined up closely together. Alternatively, a thinner (compared to the width, i.e. the Expansion in horizontal direction (see figure 2 ), the free-form lens 5, 50) air gap between the free-form lenses 5, 50 may be provided, which could be used for example for frame-shaped mounts.

The free-form lenses 5, 50 can be designed differently, which will be discussed in more detail later. Regardless of the specific embodiment, it applies to the free-form lenses 5, 50 according to the invention that they are decentered.

Depending on the specific design of the free-form lens 5, it can have, for example, such an optical axis 6 that runs through a, for example geometric, center of the LED light source 4 to a light-emitting/light-radiating surface, preferably a plane, of the LED light source 4 in the It is essentially vertical and can be set up to generate that emission cone 300 whose axis 301 is inclined by a decentration angle Φ with respect to the optical axis 6 . That is to say, the emission cone axis 301 assigned to the free-form lens 5 (preferably in the horizontal plane) encloses a decentration angle Φ with its optical axis 6 .

The light focus of the partial light distribution is on the emission cone axis. This means that the free-form lens 5 is designed in such a way that the partial light distribution 300 generated by the corresponding partial light module 3 has its highest values of light intensity or luminous intensity or luminous flux along the axis of the emission cone, i.e. the emission cone axis 301 having. This means, among other things, that the partial light distribution is brightest along the emission cone axis 301 . The optical axis 6, 60 of each free-form lens 5, 50 (regardless of the design of the free-form lens) and the reference axis 7 as well as the longitudinal axis X of the motor vehicle preferably run horizontally. The decentering angle Φ can be predetermined and correspond to the sweep (angle α), or be equal to the angle α. The optical axes 6, 60 of the partial light modules 3, 30 are directed outwards from a motor vehicle (not shown) when the light module 2 (in figure 2 a left motor vehicle headlight is shown) is properly installed in the motor vehicle. It is expedient if the decentering angle Φ is positive with respect to the emission cone axis 301, so that the optical axis 6 is inclined outwards with respect to the longitudinal axis X of the motor vehicle, towards one (in this case left) side/outside of the motor vehicle, if the light module 2 is properly positioned in the motor vehicle is installed (see figure 2 ).

Alternatively, the free-form lens 50 can be decentered in such a way that it additionally has a geometric axis 61 running through the geometric center of the free-form lens 50, which does not coincide with the optical axis 60 and is spaced from it, for example horizontally. The geometric axis 61 often runs parallel to the optical axis 60 . The geometric center means the center of gravity of the free-form lens. Such a distance 62 can vary from 1 mm to 10-20 mm, for example 5 mm, for a 35 mm wide free-form lens 50 . A partial light module 30 with the free-form lens 50 generates a partial light distribution designed as an oblique emission cone, the light center of this partial light distribution preferably being assigned to the height of the emission cone—the emission cone height 302 . This means that the highest values of the light intensity or the luminous intensity or the luminous flux of the partial light distribution lie along the height of the emission cone, ie the emission cone height 302 . This means, among other things, that this partial light distribution is brightest along the emission cone height 302 .

In connection with the present invention, the term “width of the free-form lens” is understood to mean its extension B in the horizontal direction. Such a free-form lens 50 can be arranged with respect to the corresponding LED light source 4 in such a way that its optical axis 60 coincides with the reference axis 7 associated with the LED light source 4, but its geometric axis 61 does not, with the geometric axis 61 being different from the optical axis 60 by the distance 62, preferably in a horizontal direction orthogonal to the reference axis 7. In addition, it is quite conceivable that no two of these three axes 60, 61, 7 coincide and, for example, run parallel to one another. It may be expedient to design the free-form lens 50 in such a way that the geometric axis 61 is shifted closer to the interior of the motor vehicle (not shown) with respect to the reference axis 7 when the light module 2 is properly installed in the motor vehicle. In figure 2 (Top view of a left-hand motor vehicle headlight), the geometric axis 61 is offset to the right of the reference axis 7. For a right-hand motor vehicle headlight, the geometric axis would be offset to the left of the reference axis (not shown).

The light module 2 can have different partial light modules 3 , 30 . That in the figure 2 The light module 2 shown comprises, for example, two partial light modules 3 whose free-form lenses 5 have an optical axis 6 that forms the decentration angle Φ or Φ=α with the emission cone axis 301, a partial light module 30 whose free-form lens 50 is such is designed such that its optical axis 60 deviates from its geometric axis 61, but the free-form lens 50 is arranged in such a way that its optical axis 60 coincides with the reference axis 7, a partial light module 30 whose free-form lens 50 is designed such that its optical Axis 60 deviates from its geometric axis 61, and the free-form lens 50 is arranged in such a way that its optical axis 60 does not coincide with the reference axis 7, and three partial light modules 3, 30, in which each partial light module 3, 30 is one of the above said three different sub-light modules 3, 30 can be.

By decentering the free-form lens 5, 50, each partial light module 3, 30 according to the invention emits a partial light distribution 300 that is asymmetrical with respect to the reference axis 7. The partial light distributions 300 can be designed, for example, as oblique emission cones. Depending on the design of the free-form lens 5, 50, the optical axis 6, 60 of the free-form lens 5, 50 can be inclined, for example, to the emission cone axis 301 and/or to the emission cone height 302 by a decentration angle Φ, Φ' (see Figures 6, 7 and figure 9 ).

In general, it should be noted at this point that photometric characteristics of the light distribution (e.g. the illuminance) are always related to a measurement. In vehicle construction, light distributions are usually measured in a lighting technology laboratory. Light distribution is usually measured in a lighting technology laboratory on a measuring screen that is set up at a certain distance (typically 25 meters) in front of a light module to be examined, perpendicular to its optical axis. After switching on the light module, a two-dimensional projection of the three-dimensional radiation cone is created on the measuring screen. This projection can be used, for example, to record luminous intensity or illuminance values in the form of a two-dimensional distribution and display them, for example, as an isolux line diagram (isolux lines).

figure 3 shows a perspective enlarged view of the partial light module 3 of FIG figure 2 . The free-form lens 5 of the partial light module 3 has an optical axis 6 which essentially runs through the, for example, geometric center of the LED light source 4 and towards the light-emitting/light-radiating surface 40 (for example plane 40) of the LED light source 4 vertical reference axis 7 coincides. The partial light module 3 generates a partial light distribution in the form of a radiation cone 300 the radiation cone axis 301 assigned to the free-form lens 5 is inclined by a decentration angle Φ to the optical axis 6 (and to the reference axis).

The free-form lens 5 has a (continuous) light entry surface 501 which faces the light-emitting surface 40 or plane of the LED light source 4 . Light generated by the LED light source 4 enters the free-form lens 5 through the light entry surface 501 . In addition, the free-form lens 5 has the planar light exit surface 502 through which the light that has penetrated the free-form lens 5 and propagates in the free-form lens 5 essentially without losses exits. The properties of the light and the free-form lens mentioned in this paragraph apply to all free-form lenses according to the invention.

The LED light source 4 emits according to Lambert's law, with the maximum radiant intensity preferably being emitted along the reference axis 7 . By shaping the light entry surface 501, the resulting light image and consequently the main emission direction of the partial light module (for example aligning the emission cone axis or height of the free-form lens) can be specified. Since the light entry surface 501 represents a two-dimensional surface, the shape of the light entry surface 501 can be specified, for example, by specifying two curvature values in each point of the light entry surface 501. In lighting technology, the directions along which the curvatures are specified are usually a horizontal direction H and a vertical direction V. In connection with the present invention, it can be advantageous if light entry surfaces only have horizontal and vertical lines of curvature, i.e. lines of curvature which either run in vertical or horizontal planes.

In the figure 3 The light entry surface 501 shown is asymmetrical with respect to the reference axis 7 in such a way that the optical axis 6 of the free-form lens 5 runs in the horizontal plane and encloses the decentration angle Φ with the emission cone axis 301 . The light entry surface 501 is saddle-shaped. Of the figure 3 it can be clearly seen that the horizontal lines of curvature 503 of the light entry surface 501 are concave or planar and the vertical lines of curvature 504 are convex—concave-convex light entry surface. The light entry surface 501 is less curved in the horizontal direction H than in the vertical Direction V, since the emitted partial light distribution 300 normally has a greater extent in the horizontal direction than in the vertical direction.

figure 4 shows the partial light module 3 with a free-form lens having a light entry surface 5010 that is convex both in the horizontal and in the vertical direction—convex-convex light entry surface. The horizontal lines of curvature 5030 of the light entry surface 5010 are convex, just like their vertical lines of curvature 504 . The remaining structure of the partial light module 3 of figure 4 is the structure of the partial light module figure 3 essentially the same. Although the decentering angle Φ in figure 4 equal to the decentering angle in the figure 3 is the same, these angles can of course be different.

At this point it should be noted that the free-form lenses with a concave-convex light entry surface 501, as in figure 3 , compared to the free-form lenses with a convex-convex light entry surface 5010, as in figure 4 , have an advantage, namely that they have a smaller thickness, for example central thickness 8, with otherwise approximately the same dimensions (cf Figures 3 and 4 ). The term "thickness" is understood to mean an expansion of the free-form lens along a horizontal direction running parallel to the optical axis 6 . "Central thickness" means the extension of the free-form lens along the optical axis 6 itself. Reducing the central thickness 8 enables the use of slim lens geometries and also a reduction in cycle times when manufacturing the free-form lenses from transparent plastic materials by injection molding.

figure 5 shows the partial light module 3 (for example according to figure 3 ). The free-form lens 5 of the partial light module 3 also has an optical structure on its planar light exit surface 502 . At this point it should be noted that not only the specific embodiment of the free-form lens 5 shown here can have an optical structure on its planar light exit surface, but all free-form lenses according to the invention can have this property. The optical structure can generally be in the form of structural elements distributed over the light exit surface of the free-form lens. The structural elements can be in the form of depressions or elevations, the depth or height of which can be a few micrometers to millimeters. By attaching an optical structure according to the invention, for example, the obliquity of the part light module generated emission cone or the decentering angle between the optical axis and the emission cone axis can be increased. If the partial light module is installed in a motor vehicle, this can mean that the emission cone is shifted even further towards the inside of the motor vehicle, or the partial light module radiates even more towards the inside of the motor vehicle. Concretely shows the figure 4 an optical structure made up of a plurality of sawtooth-shaped projections 80 . The sawtooth-shaped elevations 80, which can be designed, for example, as elongated prisms, which can be similar in shape to decoupling prisms in a light guide, or ribs, preferably extend along the vertical direction V transverse to a horizontal plane, with the elevation tips 81 as vertical straight lines are trained. Of the figure 5 It can be seen that the sawtooth-shaped elevations 80 can have different wedge angles 82, which enables the emitted partial light distribution, for example its homogeneity, to be adjusted very precisely.

figure 6 shows one of the partial light module 3 of FIG Figure 3 or 4 emitted partial light distribution 300 in the form of an oblique emission cone, wherein the reference axis 7 coincides with the optical axis 6 of the partial light module 3 and encloses the decentration angle Φ with the emission cone axis 301. A projection of the radiation cone 300 onto a measuring screen 10 shown schematically with an HH line hh drawn in is also shown. The light exit surface of the freeform lens is 5 in figure 6 has no optical structure in the form of sawtooth-shaped elevations. figure 7 shows one with the partial light module 3 of figure 5 generated emission cone 300. The emission cone axis 301 of this emission cone 300 encloses the decentering angle Φ′>Φ with the optical axis 6 of the partial light module 3, the optical axis 6 coinciding with the reference axis 7. A projection of the radiation cone 300 onto a measuring screen 10 shown schematically with an HH line hh drawn in is also shown. The radiation cone of figure 7 is, however, "shifted" than the radiation cone figure 6 , because the light exit surface of the free-form lens is 5 in figure 7 has an optical structure in the form of sawtooth-shaped elevations. The decentering angle Φ′ enclosed between the reference axis 7 and the emission cone axis 301 is greater than the decentering angle Φ in FIG figure 6 is. For example, one of the two decentration angles can be equal to the sweep α. It is understood that the free-form lens 5 in the Figures 6 and 7 a concave-convex light entry surface 501 or a convex-convex light entry surface 5010.

Irrespective of the specific embodiment, the radiation cones 300 according to the invention can have a horizontal opening angle of approximately 70° to approximately 80°, in particular approximately 75°, and a vertical opening angle of approximately 5° to approximately 10°. Accordingly, the partial light modules 3, 30 according to the invention, when they are properly installed in a motor vehicle, emit light horizontally in a range from about 50° on the outside of the motor vehicle to about 25° on the inside of the motor vehicle and from about 0° (or from a legally prescribed value of the reduction for shielded light distributions (ECE: -0.57° vertical)) down to about -10° vertically.

figure 8 shows a perspective enlarged view of the partial light module 30 of FIG figure 2 . As mentioned above, the decentered free-form lens 50 of the partial light module 30 has the optical axis 60 and the geometric axis 61 which does not coincide with the optical axis 60 . The geometric axis 61 preferably runs parallel to the optical axis 60 in a horizontal plane by the distance 62 . As shown, the optical axis 60 can coincide with the reference axis 7 associated with the LED light source 4 or run parallel to it. The decentered free-form lens 50 has a concave-convex light entry surface 51 and a planar light exit surface 52 . The lines of curvature of the concave-convex light entry surface 51 run either horizontally 53 or vertically 54. It is also conceivable that the free-form lens of the partial light module has a convex-convex light entry surface (not shown). In addition, the free-form lens 50 has a side cut of 9 (in figure 8 slightly gray in color). The side cut 9 shown here is preferably flat, vertically aligned and lies in a plane running parallel to the reference axis 7 . It is quite conceivable that the side trimming is not completely flat and/or is not aligned vertically and/or lies in a plane running parallel to the reference axis 7 . Due to the presence of a side trim, the free-form lens 50 is decentered. A spatial alignment of the side trim can specify the alignment of the geometric axis 61 of the trimmed free-form lens 50 (having the side trim 9). The decentered free-form lens 50 is designed in such a way that it lacks a side piece 55, which side piece 55 immediately adjoins the side trim 9 and centers the decentered free-form lens 50 again. This means, among other things, that if the side piece 55 of the free-form lens 50 were not missing, the free-form lens would be embodied symmetrically with respect to a vertical plane containing the reference axis 7, for example.

However, the terms "side trim" and "missing side piece" are not intended to indicate that centered freeform lenses are actually trimmed, resulting in a loss of lens material. Rather, the procedure for producing the decentered “trimmed” free-form lenses 50 is as follows. In a simulation program on a computer, a model of a partial light module—that is, an optical structure corresponding to this partial light module—is created. In doing so (see below), other optically relevant parameters, such as back focus and/or focal length of the free-form lens, position and type of light source, refractive index of the free-form lens material, etc., are selected as with the partial light module according to the invention (actual values are used, which result from Building specifications for partial light module according to the invention result). The model of the partial light module and in particular the free-form lens model is calculated based on a desired light distribution, for example the partial light distribution. The parameters and specifications mentioned above are used to determine how the free-form lens model (free-form lens simulation) created in the simulation program can be decentered, for example cropped, so that the model of the partial light module generates the desired partial light distribution 300 . After the free-form lens simulation is such that the calculated partial light distribution simulation equals the desired partial light distribution, the shape of the free-form lens simulation is released for manufacture. Since the free-form lens simulation can be "trimmed" in the simulation program or a cropped form of the free-form lens can be generated and further transformations can also be carried out on the free-form lens model, the terms "side trimming" and "missing side piece" mentioned above are used for the decentered free-form lenses 50 that are actually produced " is used, as these naturally result from the simulation process.

the figure 9 shows the partial light module 30 of FIG figure 8 , which generates a partial light distribution, which is designed as an oblique emission cone 300. Due to the side trimming 9 described above, the emission cone axis 301 of the emission cone 300 generated by the trimmed free-form lens 50 no longer coincides with the emission cone height 302 . It should be noted here that the light intensity of the partial light distribution 300 generated with the cropped free-form lens 50 is greatest along the optical axis 6 (and the reference axis 7). The obliquity of the emission cone 300 is produced by an asymmetry of the light entry surface 51 of the free-form lens 50 . The one in the figure 8 The asymmetry shown is due to the side trimming 9 of the free-form lens described above 50, which would have a symmetrical light entry surface without this side cut 9 and would be set up to produce a symmetrical (e.g. straight) emission cone.

How crooked the in figure 9 The radiation cone shown depends on the distance 62 , which distance 62 in turn depends on the position of the side cut 9 with respect to the reference axis 7 .

figure 10 shows section AA of the figure 8 . From this it can be seen that the vertically running lines of curvature 54 of the concave-convex light entry surface 51 of the trimmed free-form lens 50 of the light entry surface 51 of the free-form lens 50 are not mirror-symmetrical with respect to a horizontal plane running through the reference axis 7 . Below the reference axis 7, the vertical lines of curvature 54 are preferably flatter than above the reference axis 7. This can be advantageous, for example, if the partial light modules 3, 30 are used to form a light module for generating a front-end light distribution. In this case, the asymmetrical course of the lines of curvature just described is due to lighting requirements for the light distribution in front of the vehicle. A part of the light entry surface 51, in which the vertically running lines of curvature 54 are more strongly curved—above the reference axis 7 in figure 10 , can be provided to form the horizontal light-dark boundary of the front-end light distribution running just below the HH line, with another part of the light entry surface 51, in which the vertically running lines of curvature 54 are less curved - below the reference axis 7 in figure 10 , can be provided to form the so-called "tail" of the front-end light distribution. The HH line is often called "the horizon" in lighting technology and corresponds to the x-axis of a coordinate system customary for experts (also (u,v) angle specifications with regard to the HV point are conceivable), which is used when measuring the light distribution generated by motor vehicle headlights in a lighting laboratory is used. In automotive lighting technology, the "HH line" / "HH line" is a horizontal line parallel to the road through the intersection point HV of the photometric beam axis from the center of the module/light source with the measuring screen: The point HV is the origin of the measurement coordinates. One could also view the HH line as the horizon if the traffic space (the standard road) is shown in central projection from the point of view of the center of the vehicle headlight.

In connection with the present invention, illumination of the road below the horizon (the HH line) or below the legally prescribed lowering (ECE - 0.57°) to short (2-5 meters) is defined as an apron light distribution or an apron. understood in front of the vehicle. It is a shielded light distribution with a mostly straight horizontal cut-off line. But it can also be a classic low beam distribution with an increase in asymmetry. One advantage of this is that each asymmetrical light distribution is a relatively small light spot, which is why the optical components and consequently the installation space requirement can be kept small.

The regarding figure 10 The configurations described for the lines of curvature of the trimmed free-form lenses 50 are also conceivable in the case of the untrimmed free-form lenses 5 according to the invention, in particular with a concave-convex light entry surface 501. These configurations are therefore not limited to a specific embodiment.

figure 11 shows section BB of the figure 8 , which runs horizontally through the center of the cropped free-form lens 50 or contains the reference axis 7 . Again figure 11 As can be seen, the cropped free-form lens 50 has a rectangular shape in this section. This means that an intersection of the concave-convex light entry surface 51 of the trimmed free-form lens 50 (or the untrimmed free-form lens 5) with a horizontal plane containing the reference axis is a straight line. This shape is particularly well suited for those areal light sources that emit light according to Lambert's law, such as the flat LED light sources 4 used here. the figure 11 also shows the side piece 55 missing from the cropped free-form lens 50, which, as mentioned above, is designed as an extension of the decentered, cropped free-form lens 50 that is symmetrical with respect to a vertical plane running through the reference axis 7.

In general, all free-form lenses 5, 50 according to the invention have varying vertical and/or horizontal curvatures that can be adapted to the light distribution to be generated. As a result, it can be achieved, for example, that the light distribution 300 emitted by the partial light module 3, 30 has a greater illuminance in its center (in the HV point) than at its edges, whereby, for example, a prescribed light value in the HV point is that of the motor vehicle headlight 1 radiated total light distribution, for example, a front-light distribution or a Low beam distribution can be achieved. Both the front-end light distribution and the low-beam light distribution have a light-dark boundary, the course of which is specified by legal standards. In addition, further requirements can be imposed on this and other overall light distributions to be generated, such as customer-specified requirements with regard to homogeneity and luminous impression, which are preferably to be met. The legal standards mostly relate to illuminance values in areas of light distribution specified by the legislator and can differ from one another (usually insignificantly) depending on the country or region (EU, USA, Canada, Mexico, China, Japan, South Korea, etc.). The curvatures described above are therefore preferably selected in such a way that the emitted light distribution has an illuminance profile specified by the relevant standards/regulations. It goes without saying that the motor vehicle lighting device according to the invention can also be used to generate other overall light distributions, such as a high beam distribution or daylight light distribution.

In general, by designing the horizontal curvature of the light entry surface 51, a uniform drop in the front-end or basic light distributions can be achieved particularly well. The Lambertian emission characteristics of the LED light sources 4 represent an advantageous profile for this application, at least in the horizontal direction. This means, for example, that the cropped free-form lenses 50 can have a flat shape in the horizontal direction (horizontal curvature is equal to zero) and each horizontal cut of the light entry surface 51 is a straight one (however, this can also apply to uncut free-form lenses 5). This enables the lens thickness to be optimized in terms of the absolute center thickness of the lens, but above all a uniform thickness across the entire lens width. As a result, the use of slim lens geometries with a small central thickness can be made possible and/or the weight disadvantage can be reduced and/or the long cycle times in the production of such free-form lenses in the injection molding process as transparent plastic materials can be reduced.

At this point it should be noted that, as mentioned above, the planar light exit surface 52 of the trimmed free-form lens 50 also has an optical structure, for example in the form above described protruding sawtooth-shaped elevations 80, such as prisms or ribs.

figure 12 shows a schematic of a beam path in a partial light module 3, 30 according to the invention. The partial light module 3, 30 can be, for example, one of the partial light modules 3, 30 already shown in the previous figures. An enlarged detail of a horizontal section of the partial light module 3, 30 is shown, the section plane containing the reference axis 7 running horizontally. The free-form lens 5, 50 of the partial light module 3, 30 is decentered. In addition, the planar light exit surface 502, 52 has at least one, preferably several, sawtooth-shaped elevations 80, for example prisms, which are preferably straight and have a base lying parallel to the plane of the section shown. Each sawtooth-shaped elevation has at least two optically effective boundary surfaces. The sawtooth-shaped elevation 80, which is shown enlarged here and does not correspond to the actual scale, has exactly two optically effective boundary surfaces 83, 84, with a first optically effective boundary surface 83 enclosing a definable acute angle β with the planar light exit surface 52, 502 and a second optically effective boundary surface 84 is essentially orthogonal to the planar light exit surface 52, 502. The first optically effective boundary surface 83 of the sawtooth-shaped elevation is provided in order to influence the deflection of light rays which pass through the free-form lens 5, 50. The degree of this deflection depends on the definable sharpening angle β.

wobei n ₁≈1 bei Luft ist. θ_f ist dabei durch den Totalreflexionswinkel des verwendeten transparenten Materials der Linse beschränkt.The light beams 41 generated by the LED light source 4 impinge on the free-form lens 5, 50 and, after breaking twice, emerge from the free-form lens 5, 50, for example through one of the first optically effective boundary surfaces. If the angle of incidence of a light beam 41 on the light entry surface of the free-form lens 5, 50 is equal to θ , then the exit angle θ _f of the light beam 42 exiting through one of the first optically effective boundary surfaces 83, for example, is obtained according to Snell's law as follows: $${\mathrm{<figure-callout\; id="1"\; label="n"\; filenames="imgf0002.png,imgf0006.png"\; state="\{\{state\}\}">n</figure-callout>}}_1\ast \sin \left(\theta \right)={\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">n</figure-callout>}}_2\ast \sin \left({\theta }_C-\beta \right),{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">n</figure-callout>}}_2\ast \sin \left({\theta }_C\right)={\mathrm{<figure-callout\; id="1"\; label="n"\; filenames="imgf0002.png,imgf0006.png"\; state="\{\{state\}\}">n</figure-callout>}}_1\ast \sin \left({\theta }_f+\beta \right)$$

where n ₁ ≈1 for air. θ _f is limited by the total reflection angle of the transparent material used in the lens.

The acute angle β can be of different sizes for different elevations 80 . However, sometimes it is advantageous if the sharpening angle β remains the same for all sawtooth-shaped elevations 80 . As a result, the production of the free-form lenses 5, 50 can be made easier, for example. The above-described refraction and deflection of the light beams generated by the LED light source 4 leads, as mentioned above, essentially to a shift in the partial light distribution 300. However, if the acute angle β is varied, there is a further degree of freedom for design and thus for Fine adjustment of the partial light distribution 300.

Figures 13 and 14 each show the partial light modules 30 with the cropped decentered free-form lenses 50. figure 13 shows the partial light module 30, whose decentered free-form lens 50 has the sawtooth-shaped elevations 80 protruding in the form of prisms on its light exit surface 52. The free-form lens 50 is arranged with respect to the corresponding LED light source 4 such that its optical axis 60 coincides with the reference axis 7 and its geometric axis 61 is spaced from the optical axis 60 by the distance 62 in a horizontal direction orthogonal to the reference axis 7 is.

In particular, the figure 13 schematically shows that the light rays 42 are deflected more strongly by the sawtooth-shaped elevations 80 of the free-form lens 50 than light rays 42 ′ (shown in phantom) of the free-form lens without the sawtooth-shaped elevations 80 . The sawtooth-shaped elevations 80 change the angle of refraction of the exiting light beams by an angular amount Δρ that is dependent, for example, on the apex angle β.

figure 14 shows the partial light module 30, whose LED light source 4 is shifted with respect to the decentered free-form lens 50, that the LED light source 4 associated reference axis 7 does not coincide with the optical axis 60 of the decentered free-form lens 50 and is spaced from it by a distance ΔH . In this case, the geometric axis 61 of the free-form lens 50 is spaced apart from the optical axis 60 by the distance 62 . The axes shown in this embodiment: the reference axis 7, the optical axis 60 and the geometric axis 61 all lie in the horizontal plane and are parallel to each other. the figure 14 is intended to make it clear that a shift in the LED light source 4 also causes a shift in the light image due to a (in this case greater) deflection of the light beams 42 emerging from the free-form lens 50 is conceivable. The original position 4" of the LED light source, as well as light rays 42" emitted by the LED light source in its original position and refracted by the free-form lens 50 are provided with dashed lines. A change in the angle of refraction resulting from the shift by the distance ΔH is denoted by an angular amount Δφ, which can be calculated using Snell's law, for example.

Based on Figures 13 and 14 it is clear that the embodiments presented there can be combined with one another. You can namely the LED light source in the figure 13 from their original position so that the reference axis no longer coincides with the optical axis. It is also conceivable to move the LED light source in the partial light module 3 with the uncut free-form lens 5 from its original position and thereby increase the deflection of the light beams refracted by the free-form lens 5 and the asymmetry of the partial light distribution 300. This would clearly remain within the scope of the invention.

A person skilled in the art understands the angle of refraction of an emerging light beam to be an angle between the propagation direction of the refracted light beam and the normal to the refracting surface (here - to the light exit surface of the free-form lens).

It follows from what has been said above that the generation of asymmetrical partial light distributions is possible in at least three ways within the scope of the present invention: Design of the light entry surfaces and/or light exit surfaces of the free-form lenses (trimmed or non-trimmed); Attaching optical structures, in particular sawtooth-shaped elevations, such as prisms, on light exit surfaces; Shifting, for example horizontal shifting, of the lighting means, for example the light sources, with respect to the optical axes of the corresponding free-form lenses (or vice versa). It should be noted that the light entry surface is also shaped by the cutting of the free-form lenses described above.

In addition, it is apparent from the exemplary embodiments described that the above three types can be combined with one another as desired. In some situations it may be sufficient to design only the light entry surface of the free-form lens. With a very small installation space and strong sweeping, however, it is quite conceivable that all three types described above would be best used in order to take particularly strong sweeping into account.

figure 15 shows a flowchart of a method for constructing a partial light module according to the invention, for example one of the partial light modules 3, 30 described above, for a motor vehicle lighting device 1. It is that the sweep - expressed as an angle α - specified. The partial light module has an LED light source 4 corresponding to the planar light source and a decentered free-form lens. An optical axis is assigned to the free-form lens. In addition, the free-form lens includes two optically effective surfaces - a light entry surface and a flat light exit surface. An exact shape of the free-form lens is not initially specified. A position of the LED light source in relation to the free-form lens is also not specified. The position, the shape and other advantageous parameters of the free-form lens and/or the optical structure are only determined and fixed in the course of the method. First, basic parameters of the optical structure of the partial light module, such as the position and orientation of the LED light source with respect to the free-form lens, characteristics of the free-form lens itself, etc., are specified.

In step 1 S1 , a reference axis running through the center of a side of the LED light source facing the light entry surface and essentially orthogonal to this side is defined.

berechnet werden, wobei L_V eine vertikale Kantenlänge der LED-Lichtquelle ist, und ε eine in Grad ausgedrückte Position/Lage einer (photometrischen) Obergrenze (innerhalb) einer Lichtverteilung ist. Die Lage dieser Obergrenze ist gesetzlich vorgeschrieben und kann den einschlägigen gesetzlichen Normen entnommen werden. Beispielsweise ist ε = -4° laut ECE-Regelung (siehe R123 die vertikale Lage des Segments 10) beziehungsweise FMVSS-Vorgabe. "FMVSS" steht für Federal Motor Vehicle Safety Standards und ist in USA geltender Standard). Ein weiterer Grundparameter kann beispielsweise eine Mindestbreite der Freiformlinse in horizontaler Richtung sein. Diese Mindestbreite ergibt sich aus den Forderungen auf die Breite der zu erzeugenden Teil-Lichtverteilung. Da man bei diesem bevorzugten Verfahren auf die Pfeilung α abstellt, ist es zweckmäßig die Pfeilung bereits bei der Berechnung/Festlegung der Mindestbreite zu berücksichtigen. Dabei kann die Mindestbreite mit der Brennweite der Freiformlinse in folgender Relation stehen: $$l_{\mathit{Linse}}=f_{\mathit{Linse}}\ast \tan \left(\Delta +\mathrm{\alpha }\right),$$

wobei Δ - gesetzlich vorgegebener Streuungswinkel, beispielsweise 25°, und α die vorgegebene Pfeilung ist.In step 2 S2, basic parameters of the free-form lens are specified according to legal standards and the sweep and at least one size parameter of the LED light source. It is assumed that the reference axis coincides with the optical axis of the free-form lens. The basic parameters can include, for example: the material of the free-form lens or at least the refractive index of the material and/or its geometric dimensions, such as width, height, central thickness of the free-form lens. The focal length of the freeform lens, for example the LED light source can be positioned at a distance from the freeform lens equal to the focal length. The focal length of the free-form lens can depend on the dimensions of the LED light source, for example using the formula: $f_{\mathit{lens}}=\raisebox{1ex}{$L_V$}\!\left/ \!\raisebox{-1ex}{$\tan e$}\right.$

are calculated, where L _V is a vertical edge length of the LED light source, and ε is a position expressed in degrees of a (photometric) upper limit (within) a light distribution. The position of this upper limit is prescribed by law and can be found in the relevant legal standards. For example, ε = -4° according to ECE regulation (see R123 the vertical position of segment 10) or FMVSS specification. "FMVSS" stands for Federal Motor Vehicle Safety Standards and is the applicable standard in the USA). A further basic parameter can be, for example, a minimum width of the free-form lens in the horizontal direction. This minimum width results from the requirements for the width of the partial light distribution to be generated. Since this preferred method is based on the sweep α, it is expedient to take the sweep into account when calculating/determining the minimum width. The minimum width can be related to the focal length of the free-form lens as follows: $$l_{\mathit{lens}}=f_{\mathit{lens}}\ast \tan \left(\Delta +\mathrm{a}\right),$$

where Δ - legally prescribed scattering angle, for example 25°, and α is the prescribed sweep.

In step 3 S3, using the basic parameters from step 2 S2, a decentering of the free-form lens is calculated in such a way that the light generated by the LED light source by means of the free-form lens in accordance with the legal standards and the arrow in the form of a partial light distribution in front of the partial Light module is projected. At the beginning of the calculation it is assumed that the LED light source is placed in a focal surface of the free-form lens and the optical axis coincides with the reference axis. At this point it should be noted that at the end of the calculation, the optical axis no longer has to coincide with the reference axis (these axes can, for example, run parallel to one another). By horizontally shifting the LED light source, the optical axis of the decentered free-form lens manufactured according to the results of the calculation is parallel to the reference axis in many cases, as discussed with the exemplary partial light modules 3, 30 shown above. Such a calculation can be carried out, for example, using a software program, which is based on a (at the beginning of the calculation) specified light distribution, which is expressed, for example, in illuminance values in certain calculation points (usually specified by national or regional regulations) in relation to the reference axis, and basic parameters of a optical structure calculates the shape(s) of one or more optically effective (light-refracting) surfaces. It can be assumed in the calculation that the free-form lens has two optically effective (light-refracting) Surfaces - light entry surface and light exit surface - has and that the light entry surface is flat.

For example, the free-form lens can be decentered by an asymmetrical surface profile of the light entry surface. The asymmetrical surface profile can be calculated in such a way that a radiation cone axis associated with the free-form lens has a predetermined decentration angle Φ with respect to the reference axis, wherein the decentration angle Φ can correspond to the sweep, preferably can be the same as the sweep.

Now should on figure 16 be referred to briefly. This shows schematically which parameters and quantities can be used to calculate a curve—vertical in the case shown—of the light entry surface of the free-form lens. the figure 16 refers to a simulation, ie modeling of an optical setup. The computer model generated by this simulation is a model of a preferred form of a partial light module 3 according to the invention. For example, the following initial conditions can be selected for the simulation: the free-form lens 5 has a plane light exit surface 502 and a focal length f _lens ; a planar or flat LED light source 4 which has a vertical edge of length L _V is arranged in a focal point of the free-form lens 5 . In addition, FIG. 1 shows a measuring screen 10, which can also be simulated using the software program that executes the modeling of the optical structure. With such software programs, a measuring screen is provided for specifying the desired light distribution. As already mentioned, such software programs are used to determine the shape of optically effective surfaces by specifying the light distribution to be generated. A distance of the measuring screen 10 from the partial light module can preferably be set in the software program. Conveniently, this distance can be set to 25 meters, which corresponds to the distance of a light module to be tested in a lighting technology laboratory. The fact that the reference numbers used for the simulation shown in this figure are the same as the reference numbers used for the partial light modules of the embodiments described above is not intended to confuse, but only to clarify that the model created with the help of the software program is real Part light modules can be created.

The light distribution to be generated is, for example, the partial light distribution 300 (for example, lying below the HH line). Since characterizing a light distribution in each individual point is a time-consuming task, the partial light distribution 300 on the measuring screen 10 is only in a finite number given by calculation points ( L ₀ , L ₁ ,...). For example, each calculation point L _j can be assigned a pair of coordinates ( x _j , y _j ) (coordinates are often specified in degrees) and an illuminance value E _j . These calculation points ( L ₀ , L ₁ ,...) can, for example, form a rectangular grid—a so-called matrix-like distribution—on the measuring screen. For example, such a grid can choose 12 to 16 vertices in the horizontal direction and 8 vertices in the vertical direction. The grid spacing can be identical in each case. Alternatively, it is conceivable to place the corner points, which are provided for simulating a light-dark boundary, for example, at smaller distances from one another.

• Auslegungsstrategie A:
  Diese Ziel-Beleuchtungsstärkewerte werden asymmetrisch zur Bezugsachse, im Wesentlichen symmetrisch zur Abstrahlkegelachse vorgegeben. Es wird eine Freiformlinse mit großer Mittendicke geschaffen. Die Freiformlinse der Figur 4 ist ein Beispiel einer solchen Freiformlinse.
• Auslegungsstrategie B:
  Die Ziel-Beleuchtungsstärkewerte werden symmetrisch zur Bezugsachse gewählt. Durch einen einseitigen (asymmetrischen) Beschnitt - wie z.B. in Figur8 gezeigt - wird auch die Lichtverteilung beschnitten. Dadurch kann beispielsweise die Mittendicke der Freiformlinse reduziert werden.

In general, there are at least two design strategies:

• Design strategy A:
  These target illuminance values are specified asymmetrically to the reference axis, essentially symmetrically to the emission cone axis. A free-form lens with a large center thickness is created. The free-form lens figure 4 is an example of such a free-form lens.
• Design strategy B:
  The target illuminance values are chosen symmetrically to the reference axis. With a one-sided (asymmetrical) trimming - such as in Figure8 shown - the light distribution is also cut. In this way, for example, the center thickness of the free-form lens can be reduced.

Based on these calculation points, for example their coordinates and illuminance values, the surface profile of the light entry area can now be started. This can be done, for example, as follows. First, from the calculation points (Lo, L ₁ ,..., L _i ,..., L _j ,...), corresponding target angles ( ω ₀ , ω ₁ ,...) ( relative to the reference axis 7). These target angles create a correspondence between the calculation points and light exit surface points ( z ₀ , z ₁ ,..., z _i , ..., z _j ,...) of the planar light exit surface 502. Thereafter, each target angle ω _j becomes a radiation direction γ _j assigned, ie an angle between a propagation direction of a light beam Aj generated by the LED light source 4 and the reference axis 7. Subsequently, each pair ( γ _j , ω _j ) is assigned an infinitesimal surface element P _j in such a way and arranged in such a way that the light beam from the LED light source 4 in the emission direction γ _j outgoing light beam Aj is refracted at the infinitesimal surface element P _j in such a way that it leaves the free-form lens 5, 50 at the target angle ω _j . Assigning and arranging the infinitesimal surface element P _j includes, for example, its position in space and its orientation, ie the direction of its normal vector n _j . The angles η _j and ζ _j are the angles of incidence and refraction of the light beam Aj refracted by the infinitesimal surface element. It is expedient to ensure that the boundary light beams A _g are refracted in such a way that the dimensions (the width and the height) of the partial light distribution produced do not exceed certain values. For example, a legally compliant vehicle light distribution should be +/-30° wide (in horizontal direction) or a light distribution in front of the vehicle should range from the cut-off line (< -0.57°) to -12° (in vertical direction) are sufficient so that the vehicle headlight (at its usual installation height of 75 cm) shines up to 3.50 meters from the vehicle.

After the infinitesimal surface elements ( P ₀ , P ₁ ,..., P _i ,..., P _j ,...) (and thus their spatial orientations - normal vectors (n ₀ , n ₁ ,..., n _{i . _ _ _ _} ) be calculated. This is preferably achieved by using the infinitesimal surface elements ( P ₀ , P ₁ ,..., P _i ,..., P _j ,...) to construct a Non-Uniform Rational B-Spline surface, NURBS for short. area, are used. The resulting NURBS surface is the shape of the light entry surface. When constructing the NURBS surface, smoothness and continuity conditions can be imposed so that the light entry surface also meets these conditions and can be manufactured more easily.

The result of this modeling is a model of the partial light module 3 with a decentered free-form lens 5, whose optical axis 6 as reference axis 7 with the emission cone axis 301 encloses a predetermined decentration angle Φ, preferably taking account of the sweep α.

It can also be advantageous if, after the calculation of the shape of the light entry surface and consequently the modeling of the optical structure of the partial light module has been completed, a "RayTrace" - Simulation known simulation is performed to make sure whether the sample partial light distribution generated with the calculated model of the desired partial light distribution 300 is substantially the same. If the result of the "RayTrace" simulation is unsatisfactory, for example because certain legal standards are not met, the process described above should be repeated until the sample partial light distribution is essentially the same as the partial light distribution 300, with of each repetition the initial conditions, for example the target angles ( ω ₀ , ω ₁ ,...), are to be changed. The optical axis of the free-form lens 5 calculated in this way can coincide with its geometric axis.

The calculation can be carried out, for example, using the simulation program (software program) already mentioned, in which a model of an optical structure of a partial light module 30 with a decentered free-form lens 50 with a side trim 9 is generated. The creation of the free-form lens model can be done in the manner described, for example, in relation to FIG figure 16 described manner is similar. On the basis of a light distribution to be generated, for example the partial light distribution 300, target angles (taking into account the sweep α) are determined and then a surface profile of the free-form lens is calculated. In this case, the simulation (the modeling) takes place, for example, under the following boundary conditions: the optical axis of the free-form lens model runs parallel to the reference axis and to its geometric axis. All three axes can lie, for example, in a horizontal plane, with the optical axis being spaced apart from the geometric axis by a distance corresponding to the sweep, preferably horizontally. The generated free-form lens model is a model of the trimmed free-form lens 50 already described and has a planar vertical side trim that extends from the light entry surface to the light exit surface and in a vertical to which the reference axis, the geometric axis and the optical axis containing plane is arranged substantially orthogonal.

It is particularly advantageous if the model of the cropped free-form lens is such that the free-form lenses 50 generated according to this model can map a sharp HD border. The course of the partial light distribution 300 downwards can be achieved by optimizing the light entry surface in the upper and lower area.

After the surface profile of the light entry surface 51, 501, 5010 of the (not trimmed or trimmed) free-form lens 5, 50 has been determined and the model of the free-form lens 5, 50 in a simulation, for example "RayTrace" simulation, provides sufficiently good results, i.e. the sample - Partial light distribution meets quality and, above all, legal requirements, the free-form lens(es) 5, 50 is (are) produced in step 4 S4, for example by means of injection molding, so that they have a decentration calculated according to step 3 S3.

A further “shift” or increase in the obliquity of the emission cone of the partial light distribution 300 can be achieved, as described above, by attaching an optical structure to the light exit surface of the free-form lens. This attachment can be done in step 4 S4, for example by means of milling. Such an optical structure can, for example, be introduced into the injection mold as a negative mold and molded directly during the injection molding of the free-form lens.

In step 5 S5, the free-form lens 5, 50 is arranged with respect to the LED light source 4 according to the decentration calculated according to step 3 S3, with the LED light source 4 still optionally being able to be shifted with respect to the free-form lens 5, 50 in step 6 S6.

figures 17 and 18 show motor vehicles 100, 110, each with two motor vehicle headlights—one on the right and one on the left, each motor vehicle headlight comprising a number of the partial light modules 3, 30 according to the invention.

figure 17 shows motor vehicle headlights 101R and 101L, each of which comprises five partial light modules 3, 30 arranged side by side in a row in a housing provided for this purpose, with the free-form lens of one partial light module being hidden in order to expose the light source located behind it, for example the LED Light source 4 to show. The partial light modules 3, 30 are arranged flush with one another, so that the light exit surfaces of their free-form lenses 5, 50 lie in a plane that runs along the design contour of the respective motor vehicle headlight 101R, 101L and is essentially orthogonal to the corresponding reference axis 7R, 7L. The light exit surfaces have an optical structure, for example in the form of sawtooth-shaped elevations 80, 80'. The reference axes of the right and left vehicle headlights are parallel to the Reference axes of the LED light sources arranged in the individual partial light modules. Each reference axis encloses an angle with the longitudinal axis X of the motor vehicle, which angle is equal to the sweep α.

figure 18 12 shows motor vehicle headlights 101R and 101L, each motor vehicle headlight comprising six partial light modules 3, 30 arranged in a 2×3 matrix. The partial light modules 3, 30 are, as in figure 17 , arranged flush with one another, so that the light exit surfaces of their free-form lenses lie in a plane that is essentially orthogonal to the respective reference axis 7R, 7L. The light exit surfaces have an optical structure, for example in the form of sawtooth-shaped elevations 80, 80', 80", 80‴. The reference axes 70R, 70L of the right and left motor vehicle headlights run parallel to the reference axes of the LED light sources arranged in the individual partial light modules Each reference axis encloses an angle with the longitudinal axis X of the motor vehicle which is equal to the sweep α.

In addition, in the figures 12 and 13 to see that the light exit surfaces of the free-form lenses of the individual partial light modules 3, 30 can have different optical structures. For example, the sawtooth-shaped elevations can be of different heights, wedge angles of different sizes (point angle β), tooth backs of different lengths (second optical interface), etc figures 17 and 18 Motor vehicle headlights shown different partial light modules 3, 30 be set up to realize different light functions or partial light functions. For example, some of the partial light modules 3, 30 can be set up to generate a wide light distribution/approach (e.g. 40° to the left and right), with another part of the partial light modules 3, 30 can be set up to generate a contribution for the apron in the central area below the HV point of the overall light distribution, for example the low beam distribution. In addition, another part of the partial light modules 3, 30 can be set up to generate a static turning light.

Depending on the performance requirement (partial light distribution to be generated) and design, the partial light modules 3, 30 can be dimensioned accordingly and arranged in any number.

The partial light modules 3, 30 in the motor vehicle headlights 1, 1R, 1L, 101R, 101L can, for example, be controlled separately from one another if a control unit (not shown here) is assigned to the respective partial light module 3, 30. In this case, for example, a light intensity emitted by each partial light module 3, 30 can be controlled and changed. As already mentioned, other light sources can be used instead of the flat LED light sources 4 . In connection with the present invention, the term "light source" is to be understood as an object that is arranged in an object plane of the beam shaping system upstream of the light source and generates light, for example due to a p-n transition (e.g. in the case of LEDs) or due to a Light emission (in the case of a light conversion medium illuminated with laser light) or reflected (e.g. in the case of illuminated MEMS mirrors or coupling-out prisms in a light guide). The light from these light sources is fed essentially entirely (almost without losses) into the corresponding beam shaping system (in the embodiment shown—free-form lens).

As long as it does not necessarily result from the description of one of the above-mentioned embodiments, it is assumed that the embodiments described can be combined with one another as desired. Among other things, this means that the technical features of one embodiment can also be combined with the technical features of another embodiment, individually and independently of one another, as desired, in order to arrive at a further embodiment of the same invention.

The reference numerals in the claims and in the description are only intended for a better understanding of the present application and should in no way be considered as a limitation of the subject matter of the present invention.

Only parts of the motor vehicle headlight that can play a role in the present invention or in one of its embodiments are shown schematically in the figures. However, it is clear to the person skilled in the art that an operational motor vehicle headlight can immediately have other parts, such as heat sinks, supporting frames, mechanical and/or electrical adjustment devices, covers and so on. For the sake of simplicity of presentation, a detailed one is given here However, a description of these standard components of a standard motor vehicle headlight is omitted.

The terms "above", "below", "above", "below", "vertical" and "horizontal" refer to an operational, correct installation position of the partial light module and/or the motor vehicle lighting device in a motor vehicle headlight installed in a motor vehicle.

Claims (13)

1. Partial light module for a motor vehicle lighting device comprising a planar illuminant (4) and a free-form lens (5, 50), which free-form lens (5, 50) has at least two optically active surfaces - a light entry surface (51, 501, 5010) and a planar light exit surface (52, 502) - wherein the free-form lens (5, 50) is decentered with respect to a reference axis (7) extending substantially parallel to the optical axis (6, 60) of the free-form lens (5, 50) and is arranged for imaging a partial light distribution (300) in the form of a radiation cone in front of the partial light module (3, 30), the radiation cone having a radiation cone axis (301) which does not run parallel to the reference axis (7) and to the optical axis (6, 60), the reference axis (7) being assigned to the planar luminous means (4) in such a way that it is aligned with a main radiation direction of the planar luminous means (4), that it coincides with a main radiation direction of the planar light means (4) and extends substantially perpendicular to a light-emitting surface of the planar light means (4), the planar light-emitting surface (52, 502) is arranged substantially parallel to the planar light means (4),

   the partial light module (3, 30) is a light module of a direct-imaging projection type; the free-form lens (5, 50) is formed as a projection lens;

   characterized in that

   the light entrance surface (51, 501, 5010) is formed as a saddle surface and is adapted to collect the light in the vertical direction and to expand it in the horizontal direction; and

   the planar illuminating means (4) is arranged in a focal surface of the projection lens (5, 50), and the partial light distribution (300) is adapted to form an apron light distribution.
2. Partial light module according to claim 1, characterized in that the planar illuminating means (4) is arranged to generate light, the free-form lens (5, 50) is arranged to project substantially all of the light in the form of the apron light distribution
   (300) in front of the partial light module (3, 30), the light entry surface (51, 501, 5010) being provided for the entry of the light into the free-form lens (5, 50) and the planar light exit surface (52, 502) being provided for the exit of the light from the free-form lens (5, 50), the radiation cone having a horizontal aperture angle of about 70° to about 80°, in particular of about 75°, and a vertical aperture angle of about 5° to about 10°.
3. Partial light module according to claim 2, characterized in that the light entry surface (501, 5010) is designed in such a way that the free-form lens (5) has a radiation cone axis (301) enclosing a decentering angle (Φ) with the reference axis (7).
4. Partial light module according to one of the claims 1 to 3, characterized in that the free-form lens (50) has a planar vertical side cut (9), which planar vertical side cut (9) extends from the light entry surface (51) to light exit surface (52) along the reference axis (7).
5. Partial light module according to claim 4, characterized in that the free-form lens (50) has an optical axis (60) and a geometrical axis (61) deviating from the optical axis (60) and extending through geometrical center of the free-form lens (50), the optical axis (60) preferably coinciding with the reference axis (7).
6. Partial light module according to one of claims 1 to 5, characterized in that the free-form lens (5, 50) has a minimum width, which minimum width is preferably between 25 mm and 45 mm, in particular 35 mm, and/or has a focal length (fLens) of about 15 mm to 22 mm and/or height of about 12 mm to 18 mm.
7. Partial light module according to one of the claims 1 to 6, characterized in that the light entry surface (51, 501, 5010) is flat or concave in the horizontal direction and convex in the vertical direction.
8. Partial light module according to one of claims 1 to 7, characterized in that an optical structure (80) is arranged on the planar light exit surface (52, 502), which optical structure (80) preferably comprises prismatic, sawtooth-shaped elevations, in particular prisms.
9. Motor vehicle lighting device comprising at least two partial light modules according to any one of claims 1 to 8.
10. Motor vehicle lighting device according to claim 9, characterized in that the free-form lenses (5, 50) of different partial light modules (3, 30) are differently decentered.
11. Motor vehicle lighting device according to one of claims 9 to 10, characterized in that the partial light distributions (300) are superimposed on one another at least in pairs and their superimposition preferably forms an overall light distribution, for example an apron light distribution, in particular a homogeneous apron light distribution.
12. Motor vehicle lighting device according to any one of claims 9 to 11, characterized in that the light emitting surfaces (52, 502) are arranged in a common plane.
13. Motor vehicle headlamp (1, 1R, 1L, 101R, 101L) comprising at least one motor vehicle lighting device according to any one of claims 9 to 12.

Images