EP3280950B1 - Lighting device having light-guiding shield - Google Patents

Description

The invention relates to a lighting device for a motor vehicle headlight, comprising a light module with at least one light emission source, a primary optics and a secondary optics, the primary optics having at least one light-guiding attachment optics, which is set up to receive light received by the at least one light emission source through at least one light exit surface of the attachment optics to further point towards the secondary optics downstream in the optical longitudinal axis direction, and wherein the secondary optics is set up to map a light distribution that is set on the light exit surface of the front optics into a apron located in front of the lighting device, at least one radiation diaphragm being arranged between the primary optics and the secondary optics ,

It is known from the prior art that, when light beams are dispersed in an optical lens or in an optical lens system, short-wave electromagnetic radiation is refracted more than long-wave radiation at an exit surface of the optical system. Depending on the interaction with the respective optical medium, polychromatic light can cause an undesirable splitting of blue and red light components, especially at the edge areas of the optical lenses, since short-wave blue light components are broken more strongly than green ones and these in turn are broken more than comparatively long-wave red light components become.

The refractive index of lenses in an optical system also influences the imaging scale, which thus depends on the wavelength of the light. Differences in refractive index between the lens material as object space and the surrounding medium air as image space lead to different imaging scales for blue and red light components due to the wavelength dependence of the refractive index. Sub-images that are formed by light of different wavelengths are therefore of different sizes. This effect is called transverse color errors, which causes color fringes on edges of a picture subject, if these do not run radially, and which causes the picture to be blurred. The width of the color fringes of the picture motif is proportional to the distance from the center of the picture.

The focal length of the optical system and thus the distance of the image from the last surface of the optical system also depend on the refractive index of the lenses and thus on the wavelength of the light. This effect is known as the longitudinal color error. Thereby you cannot sharply catch the drawing files of different colors at the same time because they are in different positions. For example, red color fringes are in front of the selected sharpness level, blue color fringes are behind. This creates a blur that does not depend on the image height.

In order to avoid such aberrations, also called aberrations, which prevent the formation of a perfect image point when imaging an object point, as far as possible, a compromise between the requirements for the desired optical image quality and must be made when designing optical systems, in particular for headlights for motor vehicles the constructive effort can be found.

From the publication EP 2 306 074 A2 A motor vehicle headlight with a secondary optic is known, which has an achromatic arrangement of two lenses with different refractive index or with different refractive index. The achromatic lens combination of a diverging lens with a converging lens eliminates unwanted color fringes. In addition, reflecting and / or absorbing diaphragm surfaces are arranged between a light source or a primary optics and the secondary optics in such a way that an incorrect light directed in secondary emission directions outside the main beam direction is prevented from influencing the light distribution in the apron of the headlight. A disadvantage of this embodiment is at least that the achromatic lens arrangement of the secondary optics is complex and that the overall efficiency of the headlamp is reduced by the use of side diaphragm surfaces.

In the document DE 601 31 600 T3 describes a projection headlight with an ellipsoidal reflector for motor vehicles, which is designed to generate a high beam. The purpose of this headlamp is to produce a light field in front of the headlamp, which gradually becomes weaker the closer the road areas to be illuminated are in front of the headlamp. Furthermore, undesirable colorations of the light should be avoided. For this purpose, a radiation diaphragm is arranged between a light source with a reflector, which is designed as an ellipsoid of revolution, and a converging lens in such a way that the entire diaphragm is above the horizontal plane containing the optical axis, in which the focal length ranges of the reflector or the focal point of the converging lens lie , is located. For this purpose, the radiation diaphragm has an edge profile with at least two shading areas, each forming an edge, which are spaced apart in the direction of the optical axis, either one of the edges being arranged perpendicular to a focal point of the converging lens or the edges behind or in front of the focal point of the lens are arranged in the direction of the optical axis. A first, front shading area protrudes for this purpose with its edge in the upward light beam path, while a second shading area downstream in the direction of the optical axis projects with its edge in the downward light beam path. The focal point of the converging lens is located near the second focal length range of the reflector. In the document DE-A1-102010029176 , respectively. WO-A-2013/020156 , A motor vehicle headlight is shown, with a radiation diaphragm being arranged between the primary optics and the secondary optics.

In general, for the arrangement of a beam diaphragm in the beam path between a primary optic and a secondary optic, the positioning of the beam diaphragm at a greater distance from the primary optic is less sensitive to tolerances, since there is also a distance normal to the horizontal plane between the split red and blue light beams in the edge hem of the light beam , Disadvantage of the in DE 601 31 600 T3 The embodiment shown is at least that the position of the beam diaphragm with respect to the lens focal point or the focal length ranges of the reflector is fixed, which is why the position of the beam diaphragm can only be inadequately adapted to different lighting tasks. Since one and the same beam aperture protrudes both in the downward and in the upward light beam, the beam aperture must protrude comparatively far into the light beam cone for effective shading of undesired marginal edges or scattered light, thereby disadvantageously reducing the efficiency of the headlight.

From the document US 7,036,969 B2 a vehicle lamp with a special aperture geometry is known in order to minimize the formation of stray light from a fog lamp and to avoid self-glare. For this purpose, the edge profile of an apron has a central area, side areas and an upper area, which together form a triangular shape. The avoidance of chromatic aberrations is neither intended nor is it considered here. In this embodiment, too, it cannot be avoided that the aperture geometry reduces the efficiency of the optical system.

Tests on motor vehicle headlights, which include so-called "imaging light modules" with primary optics and a secondary imaging lens, such as so-called PixelLite or MatrixLight systems known from the literature, have shown that, in particular, the blue light components in the color fringe of the headlights increase Avoid, as they are clearly perceptible to the driver in the apron area, especially in the lower area of the light distribution, i.e. below the line of the horizon, the so-called HH line, and disrupt a desired light distribution as an unpleasantly irritating play of colors. The color borders are perceived so disturbingly because they stand out from the "white" light distribution of the apron. The apron is usually generated using a color-neutral reflector module.

It is therefore the object of the present invention to improve a generic lighting device for a motor vehicle headlight in such a way that the disadvantages of the prior art described are avoided as far as possible and with the lighting device both the disturbing effects of color fringes are reduced and at the same time an overall efficiency or luminous efficiency is increased.

According to the invention, this object is achieved in a generic lighting device by the features specified in the characterizing part of patent claim 1. Particularly preferred embodiments and developments of the invention are the subject of the dependent claims.

In a lighting device according to the invention for a motor vehicle headlight, comprising a light module with at least one light emission source, a primary lens and a secondary lens, the primary lens having at least one light-guiding attachment lens, which is set up to pass light received by the at least one light emission source through at least one light exit surface of the attachment lens to be directed further towards the secondary optics downstream in the optical longitudinal axis direction, and wherein the secondary optics is set up to map a light distribution that is set on the light exit surface of the front optics into an apron located in front of the lighting device, at least one radiation diaphragm being arranged between the primary optics and the secondary optics, the at least one beam diaphragm is arranged to shade a light color fringe, the at least one beam diaphragm being an optically active first diaphragm forms ante for a lower light color fringe and an optically active second diaphragm edge for an upper light color fringe, and the optically active diaphragm edges are each arranged in the light beam in such a way that blue boundary light beams of the light color fringe can be shaded selectively.

In the context of the invention, shorter-wave blue boundary light rays are understood to be those light rays whose radiation is in a wavelength range from 405 nm to 480 nm. For example, an emission wavelength of a laser diode is approximately 405 nm, which laser diode can also be used in the context of the invention in a lighting device. For this purpose, for example, segmented phosphor elements are applied to the entry surfaces and excited by corresponding laser diodes. White light LEDs also have a primary emission at wavelengths of around 450 nm.

In an illumination device according to the invention, the beam diaphragm is particularly advantageously arranged in such a way that the blue boundary light beams of the Light color fringes are shaded, since in particular the blue light components in the color fringe of the headlights in the apron area are clearly perceptible to the driver and disrupt a desired light distribution as an unpleasantly irritating play of colors. In a particularly advantageous embodiment variant, the at least one light emission source is in each case associated with an entry surface of a specific front lens and is dimmable. Different lighting tasks can thus be performed flexibly by the lighting device.

In an illumination device according to the invention, the optically active diaphragm edges are expediently arranged in the light beam in such a way that red boundary light beams reach the secondary optics without shadowing. In this embodiment of the invention, the beam diaphragm is arranged in such a way that red boundary light beams, the radiation of which lies in a wavelength range from 600 nm to 750 nm, reach the secondary optics without shading through the beam diaphragm, if possible. As was surprisingly found during examinations in advance, the red light components in the color fringe of the headlights in the apron area are barely perceptible to the driver compared to the blue light components and interfere with a desired light distribution significantly less than is the case with blue light components. In this embodiment, the overall efficiency or luminous efficacy of the headlamp is advantageously reduced only slightly, since the red light components are not shaded or are only shaded to the smallest possible extent.

However, it should be noted that the real light beam path in the light-guiding front lens comprises both direct light beams and single or multiple deflected light beams, the difference in distance between the red and blue limit light beams perpendicular to the optical axis being different. It should also be noted that the difference between the red and blue boundary light rays also depends on the material of the light-guiding front lens.

If the position of the optically active diaphragm edges is aligned, for example, on the basis of the light beam path of direct light beams, then direct light beams which have a smaller difference between the red and blue boundary light beams perpendicular to the optical axis than multiple deflected light beams will reach the secondary optics without shadowing their red border light beams. However, depending on the position of the beam diaphragm, a smaller proportion of red boundary light beams from light beams that have been deflected several times can possibly be prevented from passing through the beam diaphragm. In the opposite case, in which the position of the optically active diaphragm edges is aligned or optimized, for example on the basis of the light beam path of light beams which have been deflected multiple times, multiple deflections are made Light rays which have a greater difference between the red and blue boundary light rays perpendicular to the optical axis than direct light rays reach the secondary optics without shadowing their red boundary light rays. But even in this case, there may be at least a slight degree of shadowing of red border light rays from the direct light rays. When positioning the diaphragm edges, it is therefore important to find an optimum between shading the blue boundary light rays as completely as possible and preventing the red boundary light rays from passing through as freely as possible.

In a lighting device according to the invention, the optically active diaphragm edges between the blue boundary light rays and the red boundary light rays of the light color fringe protrude particularly advantageously into the light beam. Selectively, blue boundary light beams in a wavelength range from 405 nm to 480 nm are advantageously shaded by the beam diaphragm, while red boundary light beams in a wavelength range from 600 nm to 750 nm pass through the beam diaphragm without shadowing.

In a particularly compact embodiment of the invention, the at least one radiation diaphragm can be arranged in a diaphragm plane substantially perpendicular to the optical longitudinal axis in a lighting device. In this version, the diaphragm edges of the radiation diaphragm are in one and the same diaphragm plane. The radiation diaphragm can be made in one part or in several parts. The at least one radiation diaphragm preferably has smoothly encircling diaphragm edges without structured subdivisions such as, for example, webs, frames, reinforcements or the like, since structured or segment-like composed diaphragm plates with subdivided diaphragm edges are disadvantageously depicted as disruptive strips in the traffic area or on a roadway. The arrangement of the beam diaphragm in a diaphragm plane makes the adjustment of the beam diaphragm in the direction of the optical longitudinal axis particularly simple.

In an advantageous embodiment variant of the invention, the radiation diaphragm can be made in one piece in a lighting device and have a diaphragm recess which forms a continuous optically active diaphragm edge with a first diaphragm edge section for a lower light color fringe and a second diaphragm edge section for an upper light color fringe, the diaphragm edge in the installed position encloses optical longitudinal axis. A one-piece radiation diaphragm is particularly simple to manufacture and to assemble within the lighting device. Furthermore, a one-piece radiation diaphragm with a continuous, smooth all-round diaphragm edge without structured subdivisions such as webs or reinforcements has the advantage that the light distribution in front of the lighting device without disruptive Strip is mapped. In the event that a primary optic with several front optics or with a front optic with several light guides is used, the continuous, smooth all-round diaphragm edge offers the advantage that the light distribution of all the front optics or all light guides together through one aperture recess is projected, which results in a particularly homogeneous light distribution without annoying stripes due to the smooth peripheral edge of the diaphragm.

In a further advantageous embodiment variant, the radiation diaphragm can be embodied in two parts in a lighting device according to the invention, a first diaphragm part with a first optically active diaphragm edge and a second diaphragm part with a second optically active diaphragm edge being arranged on opposite sides of the optical longitudinal axis. In this two-part design of the radiation diaphragm, the two optically active diaphragm edges on the first and on the second diaphragm part can be adapted particularly flexibly to the geometric conditions of the beam path within an illumination device. The diaphragm edges can thus also be arranged asymmetrically with respect to a horizontal plane through the optical longitudinal axis. In this embodiment variant with a two-part radiation diaphragm, the two optically active diaphragm edges are each preferably continuously smooth without structuring, webs or interruptions, in order to ensure that the light distribution in the run-up to the lighting device is reproduced without disruptive strips.

In a further embodiment of a lighting device according to the invention, the first diaphragm part and the second diaphragm part can expediently be arranged in different diaphragm planes spaced apart from one another in the optical longitudinal axis direction. In this variant of the invention, the diaphragm edges can be arranged particularly flexibly in the beam path of the light beam in order to selectively shade blue boundary light beams of the light color fringe.

In an advantageous development of the invention, at least one optically active diaphragm edge can be a free-form curve. Since the geometries of motor vehicle headlights, in particular, are determined by numerous influencing factors, such as, for example, constructive specifications, the requirements of authorities and design requirements of the motor vehicle manufacturers, the geometries of the diaphragm edges of the radiation shield must also be able to be adapted to the respective geometric specifications of the motor vehicle headlight concerned. The easiest way to do this is by using an aperture edge that is designed as a free-form curve. As already stated above, the at least one optically active diaphragm edge is preferably a smooth free-form curve designed that has no structures such as webs, frames or similar interruptions. Spline interpolation, for example, can be used to define or calculate such a smooth free-form curve, with the aid of which predefined interpolation points are interpolated with the aid of piecewise continuous polynomials, so-called splines, in order to advantageously obtain a smooth, uninterrupted curve shape.

In an illumination device according to the invention, preference is given to the at least one beam diaphragm in the optical longitudinal axis direction from a lens focal plane at a distance of 10% to 90%, preferably from 30% to 70%, particularly preferably 50%, of an intercept distance between the lens focal plane and a lens apex plane of the secondary optics spaced. In this embodiment, the radiation diaphragm is fixed between the lens focal plane and the lens apex plane of the secondary optics.

In a lighting device according to the invention, it is particularly advantageous that the distance of the at least one beam diaphragm from the lens focal plane by color sensor measurements and / or color simulation calculations as the difference between the relative difference between a red light component shielded by the beam diaphragm and the red light component in the light beam passing through without the beam diaphragm and the relative difference between one the blue light component shielded by the radiation diaphragm can be determined compared to the blue light component in the light beam which is continuous without a radiation diaphragm, an increased blue light component being shadowed if there is a positive difference and an increased red light component being shadowed by the radiation diaphragm if the difference is negative. In this embodiment variant, the relative differences between shielded red light components or blue light components due to the shielding of the corresponding light components on the radiation shield from the red light components or blue light components is advantageous for a diaphragm position of the beam diaphragm selected at a certain distance from the lens focal plane in the direction of the optical longitudinal axis determined without a diaphragm. For this purpose, the radiation diaphragm or the diaphragm edges of the beam diaphragm are examined at different normal distances from the optical axis, each at the same distance from the lens diaphragm from the lens focal plane in the direction of the optical longitudinal axis, and an optimal position of the diaphragm edges with regard to the efficiency of the lighting device, selectively blue Shadow border light rays, determined. By iteration of the distance of the beam diaphragm from the lens focal plane in the direction of the optical longitudinal axis, these relative measurements are repeated for different distances from the lens focal plane. Experimental measurements can thus show a course of the difference in the relative difference between a red light component shielded by the radiation diaphragm and that without The continuous red light component in the light beam and the relative difference between a blue light component shielded by the radiation shield compared to the blue light component in the light beam passing through without the radiation shield are determined as a function of the distance of the radiation shield from the lens focal plane in the direction of the optical longitudinal axis.

In practice, in addition to or as an alternative to the "real" measurement method described above, "virtual" measurements are increasingly being carried out on a real prototype of a headlight by means of simulation calculation. For example, a Raytrace® simulation program is used for such "virtual" determinations or calculations.

The preferred distance of the beam diaphragm or the diaphragm edges of the beam diaphragm normal to the optical longitudinal axis is determined in each case as a compromise between the desired shading of the blue boundary light rays and the overall efficiency of the lighting device to be achieved. Since the overall efficiency of the lighting device also decreases with greater shading, the respective position of the radiation diaphragm must therefore be selected such that the shielded blue light component is higher than the proportion of shielded red boundary light beams.

In a preferred embodiment of the invention, in the case of an illumination device for distances of the beam diaphragm from the lens focal plane in the direction of the optical axis, the difference between the relative difference between a red light component shielded by the beam diaphragm and the red light component passing through without the beam diaphragm in the light beam and the Relative difference between a blue light component shielded by the radiation diaphragm and the blue light component in the light beam which is continuous without a radiation diaphragm has a value of 0.1 to 0.2. In the case of the determined positive differences with values of 0.1 to 0.2, an increased proportion of blue light is advantageously shaded selectively, the overall efficiency of the lighting device nevertheless remaining high.

In a lighting device according to the invention, the at least one radiation diaphragm is expediently fastened on a primary optics holder together with the primary optics. In this version, the radiation diaphragm and the primary optics are particularly conveniently attached together.

In a particularly compact embodiment of the invention, the at least one radiation diaphragm is integrated into the primary optics in a lighting device.

In addition to the advantages of a particularly compact construction of the unit consisting of primary optics and radiation diaphragm, the position of the radiation diaphragm cannot be unintentionally adjusted in relation to the primary optics, which represents a further advantage of this embodiment.

In a lighting device according to the invention, a difference between a blue border light beam and a red border light beam transverse to the optical longitudinal axis is advantageous depending on the distance in the optical longitudinal axis direction and depending on the material of the light-guiding front lens system. Experiments have shown that, for example, polycarbonate as the light-conducting material has a particularly clear color splitting, and polycarbonate has particularly large difference distances between blue and red boundary light beams. Selective shading of blue boundary light beams is therefore particularly easy due to the large difference in distances transverse to the optical longitudinal axis direction in the case of a light-guiding front lens made of polycarbonate.

In a lighting device according to the invention, the secondary optics expediently comprises a projection lens with a lens entry surface, which can be flat or spherical, and a mostly aspherical lens exit surface. This embodiment of a lighting device according to the invention can advantageously be used in headlights with imaging optics. The light modules of such headlights are usually referred to as light modules with front optics and a downstream projection lens.

In a development of the invention, the lighting device is set up to generate a low beam or high beam distribution. Advantageously, a dipped beam or high beam distribution can advantageously be achieved with the at least one beam diaphragm, in which in each case blue boundary light beams are selectively shaded in the light color fringe. The change between low beam and high beam is usually carried out by appropriately designing the combination of one or more light sources with the front lens system.

Furthermore, the invention comprises a motor vehicle headlight with at least one lighting device according to the invention. Motor vehicle headlights are thus advantageously provided with a lighting device according to the invention, which enable a "white" or color-neutral light distribution of the illuminated apron without disturbing blue colored light edges. Motor vehicle headlights equipped with the lighting device according to the invention are therefore perceived as particularly high quality due to their uniform, color-neutral light distribution.

In addition, a motor vehicle with at least one motor vehicle headlight that is equipped with at least one lighting device according to the invention can be specified within the scope of the invention. The aforementioned advantages of the lighting device according to the invention thus also apply to the motor vehicle equipped with at least one motor vehicle headlight.

• Fig. 1 in einer isometrischen Ansicht einen schematischen Aufbau einer ersten Ausführungsform einer erfindungsgemäßen Beleuchtungsvorrichtung;
• Fig. 2 in einer teilweisen Schnittansicht von der Seite eine weitere Ausführungsvariante einer erfindungsgemäßen Beleuchtungsvorrichtung;
• Fig. 3 eine Detailansicht von der Seite des Lichtstrahlengangs eines direkten Lichtstrahls in der Vorsatzoptik;
• Fig. 4 eine Detailansicht von der Seite des Lichtstrahlengangs mit zweifach-umgelenktem Lichtstrahl in der Vorsatzoptik;
• Fig. 5 bis 7 jeweils in Diagrammdarstellung für unterschiedliche Materialien der lichtleitenden Vorsatzoptik den Verlauf des Differenzabstands Δy zwischen Grenzlichtstrahlen als Funktion des Winkels ϕ zwischen optischer Achse und Grenzlichtstrahl;
• Fig. 8 in einer Seitenansicht eine erfindungsgemäße Beleuchtungsvorrichtung mit einer Blendenposition der Strahlenblende bei halber Schnittweite;
• Fig. 9 in Diagrammform den Verlauf des Auswahlkriteriums Δ(R-B) als Funktion des Abstands z der Strahlenblende von der Linsenbrennpunktebene zu Bestimmung einer geeigneten Blendenposition im Strahlengang;
• Fig. 10 in einer schematischen isometrischen Ansicht von der Seite eine alternative Position einer farbkorrigierenden Strahlenblende als Teil der Vorsatzoptik-Halterung;
• Fig. 11 in einer isometrischen Ansicht schräg von oben die in Fig. 10 veranschaulichte farbkorrigierende Strahlenblende als Teil der Vorsatzoptik-Halterung;
• Fig. 12 in einer Frontalansicht die in Fig. 11 dargestellte Anordnung;
• Fig. 13 in einer teilweisen Schnittansicht schräg von der Seite den Verlauf der Blendenkanten bei dem in Fig. 10 bis Fig. 12 gezeigten Beispiel samt der Primäroptikhalterung;
• Fig. 14 eine Detailansicht von der Seite die Abschattung von Grenzlichtstrahlen eines in der Vorsatzoptik direkt geleiteten Lichtstrahls.

Further details, features and advantages of the invention result from the following explanation of an exemplary embodiment shown schematically in the drawing. The drawings show:

• Fig. 1 an isometric view of a schematic structure of a first embodiment of a lighting device according to the invention;
• Fig. 2 in a partial sectional view from the side a further embodiment variant of a lighting device according to the invention;
• Fig. 3 a detailed view from the side of the light beam path of a direct light beam in the front optics;
• Fig. 4 a detailed view from the side of the light beam path with double-deflected light beam in the front lens;
• 5 to 7 in each case in a diagram for different materials of the light-guiding front lens, the course of the difference distance Δy between boundary light beams as a function of the angle ϕ between the optical axis and the boundary light beam;
• Fig. 8 a side view of an illumination device according to the invention with an aperture position of the radiation diaphragm at half the focal length;
• Fig. 9 in diagram form the course of the selection criterion Δ (RB) as a function of the distance z of the beam diaphragm from the lens focal plane to determine a suitable diaphragm position in the beam path;
• Fig. 10 in a schematic isometric view from the side, an alternative position of a color-correcting radiation diaphragm as part of the optical attachment holder;
• Fig. 11 in an isometric view obliquely from above the in Fig. 10 illustrated color-correcting diaphragm as part of the front lens mount;
• Fig. 12 in a front view the in Fig. 11 arrangement shown;
• Fig. 13 in a partial sectional view obliquely from the side, the course of the diaphragm edges in the in 10 to 12 shown example including the primary optics holder;
• Fig. 14 a detailed view from the side of the shadowing of limit light rays of a light beam directly guided in the front optics.

Fig. 1 illustrates a schematic structure of a first embodiment of a lighting device 1 according to the invention with a light module 2 and with at least one light emission source 10 or with at least one light emission point 10. A primary optic 100, which is connected here to the light emission sources 10, has a light-conducting material made of transparent material for this purpose Front optics 102 with a plurality of light guides 102 each with light entry surfaces 101 and with light exit surfaces 103. Light rays 50, which are indicated here by dashed lines, change from the light exit surfaces 103 of the front optics 102 to a secondary optics 300, which here is designed as a projection lens 303 with a lens entry surface 301 and a lens exit surface 302 and which is spaced apart from the primary optics in the direction of an optical longitudinal axis 150 , headed. For this purpose, a beam diaphragm 200 is arranged in the light beam path in a diaphragm plane 210, with diaphragm edges 220 of the beam diaphragm 200 projecting into the light beam 50 in such a way that blue boundary light beams 51 or blue light components 51 of a light color fringe 250, 251, 252 of the light beam 50 are shadowed while red border light rays 52 or red light portions 52 pass through the beam diaphragm 200 unhindered and thus reach the secondary optics 300 without shadowing. The radiation diaphragm 200 is made here in one piece with a diaphragm recess 215 and with a circumferential, smooth, continuous diaphragm edge 220. The coordinate system used here is outlined in the drawing at the bottom left, to which reference is made below. The z-axis direction is defined here by the direction of the optical longitudinal axis 150 of the lighting device 1. The aperture plane 210 is arranged essentially perpendicular to the optical longitudinal axis 150 or perpendicular to the z-axis direction.

Fig. 2 shows a lighting device 1 according to the invention in a partial sectional view from the side. The radiation diaphragm 200 is designed here in two parts, a first diaphragm part 201 being equipped with a first, smooth, continuous diaphragm edge 221 and a second diaphragm part 202 having a second diaphragm edge 222. The second diaphragm edge 222 is also designed to be smooth and continuous without subdivisions or interruptions. The first diaphragm part 201 and the second diaphragm part 202, which together form the radiation diaphragm 200, are each arranged in the same diaphragm plane 210. The first diaphragm part 201 is attached below a horizontal plane by the optical longitudinal axis 150, while the second diaphragm part 202 provides the diaphragm edge 222 arranged above the horizontal plane by the optical longitudinal axis 150. The lower or first diaphragm edge 221 is spaced from the optical longitudinal axis 150 at a normal distance y ₁ in the negative y coordinate direction. The upper or second diaphragm edge 222 is in here a normal distance y ₂ in the positive y coordinate direction from the optical longitudinal axis 150. Light rays 50, which pass through the beam diaphragm 200 and boundary light rays 51, 52, which form a light color fringe 250, are again illustrated as dashed arrows. Blue border light rays 51 or blue light components 51 of an upper light color fringe 251 and a lower light color fringe 252 are in each case selectively shaded by the first diaphragm part 201 or by the second diaphragm part 202. Red border light rays 52 or red light portions 52 of the upper light color fringe 251 and of the lower light color fringe 252 pass the shade edges 221, 222 to the secondary optics without shadowing. The diaphragm plane 210 is arranged at a distance z from a lens focal plane 110. The entire distance between lens focal plane 110 and lens apex plane 310 is referred to as the focal intercept SW.

Fig. 3 shows a detailed view of the light beam path of a direct light beam 50 in the light-conducting optical attachment 102. The optical attachment 102 here has a length 120 in the direction of the optical longitudinal axis 150. Light, which is generated in the light emission sources 10, arrives at the light entry surface 101 into the light-guiding attachment optics 102 and leaves it again at the opposite light exit surface 103. The individual light guides of the light-guiding attachment optics 102 here have, for example, rectangular cross sections, which differ from the light entry face 101 expand substantially conically towards the light exit surface 103. The front optics 102 or the individual light guides 102 have an opening angle α in the direction of the light exit surface 103. The direct light rays 50 guided through the front optical system 102 are split into blue boundary light rays 51 or red boundary light rays 52 in the region of the light color fringe when they exit from the light-guiding front optical system 102. The comparatively short-wave blue radiation or the blue light component 51 is refracted more than the comparatively long-wave red radiation or the red light component 52. An exit angle ϕ _{1, B} between the optical longitudinal axis 150 and the blue boundary light beam 51 is thus greater than an exit angle ϕ _{1, R} between the optical axis 150 and the red boundary light beam 52. Likewise, there is a normal distance y _{(B) of} the blue boundary light beam 51 from the optical one Longitudinal axis 150, which is measured in the aperture plane 210, greater than a normal distance y _{(R) of} the red boundary light beam 52 from the optical longitudinal axis 150. A difference Δy between red and blue boundary light beams 51, 52, measured as the normal distance to the optical longitudinal axis 150 in FIG The aperture plane 210 is larger, the greater the distance z of the aperture plane 210 from the plane 110 through the lens focal point. Furthermore, the difference distance Δy depends on the material selection of the light-conducting front lens 102, as in the following figures 5 to 7 is illustrated.

Fig. 4 shows a schematic detailed view of the light beam path of a double-deflected light beam 55 in the front optics 102. The redirected light beam 55 emerges at an exit angle ϕ ₀ in relation to the direction of the optical longitudinal axis 150 at the light exit surface 103 of the front optics 102. In the area of the light color fringe, the blue boundary light rays 51 or the blue light component 51 are in turn refracted more than the red boundary light rays 51 or the red light component 52. An exit angle ϕ _{01, B} between the optical axis 150 and the blue boundary light beam 51 is in turn larger than an exit angle ϕ _{01, R} between the optical axis 150 and the red boundary light beam 52. The diaphragm edge, not shown here, becomes in this way in the diaphragm plane 210 with its diaphragm edge positioned that the diaphragm edge is arranged at a normal distance from the optical longitudinal axis 150, which lies between the normal distance y _{(B) of} the blue boundary light beam 51 and the normal distance y _{(R) of} the red boundary light beam 52. The difference distance Δy between the red and blue limit light beams 51, 52 is in that in Fig. 4 shown beam path of a double-deflected light beam 55 slightly larger than in the case of the in Fig. 3 illustrated beam path of a direct light beam 50.

It is thus clear to the person skilled in the art that, depending on whether the positioning of the optically active diaphragm edges takes place on the basis of the differential distance Δy of the direct light rays 50 or the light rays 55 which have already been deflected in the light-conducting optical attachment 102, it may also be to a lesser extent for shadowing red boundary light rays can come. When positioning the diaphragm edges, it is therefore important to find an optimum between shading the blue boundary light rays as completely as possible and preventing the red boundary light rays from passing through as freely as possible.

The illustrations 5 to 7 each show in a diagram for different materials of the light-conducting front lens system 102 the course of the differential distance Δy between blue 51 and red 52 boundary light beams as a function of the exit angle ϕ between the optical longitudinal axis 150 and the respective boundary light beam 51, 52. Fig. 5 shows the courses of the differential distance Δy for a light guide 102 made of polymethyl methacrylate (PMMA), the data series for different distances z being determined at 10 mm, 50 mm and 80 mm distance from the lens focal plane or from the primary optics 100. It can be seen that with a larger distance z of 80 mm from the primary optics, the difference distance Δy is greater than with the same exit angle ϕ with a smaller distance z. For example, with a light guide made of PMMA at a distance z of 80 mm with an exit angle ϕ of 20 °, the difference Δy is approximately 0.4 mm.

In Fig. 6 , in which the courses of the differential distance Δy were determined for a light guide 102 made of silicone, the data series also being shown for different distances z in 10 mm, 50 mm and 80 mm distance from the lens focal plane or from the primary optics 100, for example in a distance z of 80 mm at an exit angle ϕ of 20 °, the difference Δy about 0.3 mm.

Fig. 7 illustrates the courses of the differential distance Δy for a light guide 102 made of polycarbonate (PC). The data series for different distances z are also shown here at 10 mm, 50 mm and 80 mm from the lens focal plane or from the primary optics 100. For example, for a light guide made of polycarbonate at a distance z of 80 mm at an exit angle ϕ of 20 °, the difference Δy is approximately 1.0 mm.

A comparison of the three investigated materials PMMA, silicone and PC shows that a light guide made of polycarbonate (PC) is particularly well suited due to the comparatively large difference Δy between emerging blue and red boundary light beams, in order to combine with an illumination device according to the invention in combination with one in the beam direction downstream shield to selectively shade disturbing blue border light beams.

Fig. 8 shows a so-called "PixelLite" light module 2 with a diaphragm position 210 of the beam diaphragm 200 at half the focal length SW. The aperture plane 210 is thus arranged exactly in the direction of the optical longitudinal axis 150 exactly between the plane 110 through the lens focal point and the lens apex plane 310.

Fig. 9 shows in diagram form the course of the selection criterion Δ (RB) as a function of the distance z of the beam diaphragm 200 from the lens focal plane 110 to determine a suitable diaphragm position 210 in the beam path between the primary optics 100 and the secondary optics 300. For this purpose, the Radiation diaphragm 200 from the lens focal plane 110 from color sensor measurements a difference Δ (RB) of the relative difference between a red light component R shielded by the beam diaphragm 200 compared to the red light component R in the light beam 50 passing through without the beam diaphragm and the relative difference between a blue light component B shielded by the beam diaphragm 200 compared to the blue light component B in the light beam 50 which is continuous without a beam diaphragm. By iteration of the distances z of the radiation diaphragm 200 and by variation of the normal distance of the diaphragm edge 220 in the x-coordinate direction or in the y-coordinate direction, in each case measured away from the optical longitudinal axis 150, the example in FIG Fig. 9 shown course determined. If the difference Δ (RB) is positive, an increased proportion of blue light B is shadowed, and if the difference Δ (RB) is negative, an increased proportion of red light R is shadowed by the diaphragm 200. In the exemplary embodiment shown here, an aperture position with a distance z of 20 mm to 25 mm is advantageously to be selected in order to achieve selective shading of the blue light component B on the one hand and to ensure high efficiency of the overall system on the other hand. The difference Δ (RB) is from 0.1 to 0.2, the distance z and the difference Δ (RB) being directly proportional. In the case of greater shading, red light components R are also shaded, and consequently the overall efficiency drops or the measured difference Δ (RB) has negative values.

Fig. 10 shows an alternative position of a color-correcting radiation diaphragm 200 as part of an attachment optics holder 105. Here, the radiation diaphragm 200 is integrated in the primary optics 100 and is fastened together with the primary optics holder.

Fig. 11 puts the in diagonally from above Fig. 10 illustrated color-correcting diaphragm 200 as part of the optical attachment holder 105. The diaphragm plane 210 of the diaphragm 200 is arranged here within a light exit cone 500 with a boundary edge 510.

Fig. 12 shows in a front view the in Fig. 11 arrangement shown, the diaphragm edges 221, 222 are shown in dashed lines. The aperture edges 221, 222 each have courses of free-form curves 240 here.

In Fig. 13 the primary optics holder 105 is shown partially cut away. The diaphragm edges 221, 222 in the form of a free-form curve 240 are formed here by the primary optics holder 105. The radiation diaphragm 200 is thus integrated in the primary optics holder 105.

Fig. 14 shows - comparable to Fig. 3 - In a detailed view from the side, the shadowing of limit light beams 51, 52 of a light beam 50 which is directly guided in the front optical system 102. However, here in Fig. 14 in contrast to Fig. 3 an aperture part 202 of a radiation diaphragm 200 is also shown. A blue border light beam 51 of the light color fringe 251 is shaded here by the beam diaphragm 200, while a red border light beam 52 passes through the diaphragm plane 210 without shading and thus advantageously contributes to the overall efficiency of the lighting device 1.

LIST OF POSITION SIGNS

1

lighting device

2

light module

10

Light emission source or light emission point

50

beam of light

51

blue border light beam or blue light component

52

red border light beam or red light component

55

deflected light beam

100

primary optics

101

Light entry surface of the front lens

102

Light guide, individual light-guiding attachment optics

103

Light exit surface of the front lens

105

Primary optics holder

110

Plane through lens focal point

120

Length of the front lens

150

optical longitudinal axis

200

beam collimator

201

first aperture part

202

second aperture part

210

stop plane

215

Blendenausnehmung

220

diaphragm edge

221

first or lower diaphragm edge or diaphragm edge section

222

second or upper diaphragm edge or diaphragm edge section

240

Freeform curve

250

Edge of light color (light rays dashed)

251

upper edge of light color (light rays dashed)

252

lower edge of light color (light rays dashed)

300

secondary optics

301

Lens entrance surface

302

Lens exit surface

303

projection lens

310

Linsenapexebene

500

Light exit cone

510

Limiting edge of the light exit cone

R

red light fraction

B

Blue light component

SW

Focal length, distance between lens focal plane and lens apex plane

y

Normal distance to the optical axis

Dy

Difference distance between limit light beams

z

Distance between lens focal plane and aperture plane

α

Opening angle of the front lens

φ

Exit angle between the optical axis and the limit light beam

ϕ ₀

Impact angle with multiple reflection in the front lens

Claims (18)

1. Illumination device (1) for a motor vehicle headlight, comprising a light module (2) with at least one light emission source (10), a primary optical system (100), and a secondary optical system (300), wherein the primary optical system (100) has at least one light-conducting ancillary optical system (102), which is arranged to direct light (50) captured from the at least one light-emitting source (10), through at least one light-emitting surface (103) of the ancillary optical system, onward onto the secondary optical system (300), which is arranged downstream in the direction of the optical longitudinal axis (150), and wherein the secondary optical system (300) is set up so as to map a light distribution occurring on the light exit surface (103) of the ancillary optical system into a field in front of the illumination device (1), wherein at least one beam diaphragm (200) is arranged between the primary optical system (100) and the secondary optical system (300),
   characterised in that,
   the at least one beam diaphragm (200) is arranged for the purpose of masking a colour fringe of the light (250), wherein the at least one beam diaphragm (200, 201, 202) forms an optically active first diaphragm edge (221) for a lower colour fringe of the light (252), together with an optically active second diaphragm edge (222) for an upper colour fringe of the light (251), and the optically active diaphragm edges (220, 221, 222) are each arranged in the light beam (50) such that blue threshold light beams (51) of the colour fringe of the light (250, 251, 252) can be selectively masked.
2. Illumination device (1) according to Claim 1,
   characterised in that, the optically active diaphragm edges (220, 221, 222) are each arranged in the light beam (50) such that red threshold light beams (52) reach the secondary optical system (300) without being masked.
3. Illumination device (1) according to Claim 1 or 2,
   characterised in that, the optically active diaphragm edges (220, 221, 222) protrude into the light beam (50) between the blue threshold light beams (51) and the red threshold light beams (52) of the colour fringes of the light (250, 251, 252).
4. Illumination device (1) according to one of the Claims 1 to 3, characterised in that, the at least one beam diaphragm (200, 201, 202) is arranged in a diaphragm plane (210) essentially at right angles to the optical longitudinal axis (150).
5. Illumination device (1) according to one of the Claims 1 to 4, characterised in that, the beam diaphragm (200) is embodied in one piece, and has a diaphragm aperture (215), which forms a continuous optically active diaphragm edge (220) with a first diaphragm edge section (221) for a lower colour fringe of the light (252), and a second diaphragm edge section (222) for an upper colour fringe of the light (251), wherein in the installed position the diaphragm edge (220) encloses the optical longitudinal axis (150).
6. Illumination device (1) according to one of the Claims 1 to 4, characterised in that, the beam diaphragm (201, 202) is embodied in two parts, wherein a first diaphragm part (201) with a first optically active diaphragm edge (221) and a second diaphragm part (202) with a second optically active diaphragm edge (222) are arranged on opposite sides of the optical longitudinal axis (150).
7. Illumination device (1) according to Claim 6,
   characterised in that, the first diaphragm part (201) and the second diaphragm part (202) are arranged in different diaphragm planes (210), spaced apart from one another in the direction of the optical longitudinal axis (150).
8. Illumination device (1) according to one of the Claims 1 to 7, characterised in that, at least one optically active diaphragm edge (220, 221, 222) is a free-form curve (240).
9. Illumination device (1) according to one of the Claims 1 to 8, characterised in that, the at least one beam diaphragm (200, 201, 202) is spaced apart, in the direction of the optical longitudinal axis (150), from a lens focal point plane (110) at a distance (z) of 10 % to 90 %, preferably of 30 % to 70 %, particularly preferably of 50 %, of a focal length spacing (SW) between the lens focal point plane (110) and a lens apex plane (310) of the secondary optical system (300) .
10. Illumination device (1) according to one of the Claims 1 to 9, characterised in that, the distance (z) of the at least one beam diaphragm (200, 201, 202) from the lens focal plane (110) can be determined, by colour sensor measurements and/or colour simulation calculations, as the difference Δ (R-B) of the relative difference between a red light component (R) in the light beam (50) shielded by the beam diaphragm (200, 201, 202) with respect to the red light component (R) in the light beam (50) passing through without a beam diaphragm, and the relative difference between a blue light component (B) in the light beam (50) which is shielded by the beam diaphragm (200, 201, 202) with respect to the blue light component (B) in the light beam (50) passing through without a beam diaphragm, wherein in the case of a positive difference Δ (R-B) an increased blue light component (B) is masked, and in the case of a negative difference Δ (R-B) an increased red light component (R) is masked, by the beam diaphragm (200, 201, 202).
11. Illumination device (1) according to Claim 10,
    characterised in that, for a distance (z) of the beam diaphragm (200, 201, 202) from the lens focal plane (110) of 20 mm to 25 mm, the difference Δ (R-B) is a value of 0.1 to 0.2.
12. Illumination device (1) according to one of the Claims 1 to 11, characterised in that, the at least one beam diaphragm (200) is attached to a primary optical system mounting (105), together with the primary optical system (100).
13. Illumination device (1) according to one of the Claims 1 to 12, characterised in that, the at least one beam diaphragm (200) is integrated into the primary optical system (100).
14. Illumination device (1) according to one of the Claims 1 to 13, characterised in that, a differential distance (Δy) between a blue threshold light beam (51) and a red threshold light beam (52) transverse to the optical longitudinal axis (150) is a function of the distance (z) in the direction of the optical longitudinal axis (150) and is also a function of the material of the light-conducting ancillary optical system (102).
15. Illumination device (1) according to one of the Claims 1 to 14, characterised in that, the secondary optical system (300) comprises a projection lens (303) with a lens entry surface (301) and a lens exit surface (302).
16. Illumination device (1) according to one of the Claims 1 to 15, characterised in that, the illumination device (1) is set up so as to generate a dipped beam or a full beam distribution.
17. Motor vehicle headlight with at least one illumination device (1) according to one of the Claims 1 to 16.
18. Motor vehicle with at least one motor vehicle headlight according to Claim 17.

Images