EP3636993A1 - Illumination device for a motor vehicle and motor vehicle with same - Google Patents

Abstract

The invention relates to a lighting device (101) for a motor vehicle. This comprises a laser light source (4) for emitting laser light (7), a radiation converter (6), which contains a luminescent layer, in particular with phosphorus, and imaging optics (1). The radiation converter (6) is designed to convert and fan out laser light (7) emitted by the laser light source (4) into broadband, in particular white, secondary light (8) compared to the laser light (7). The imaging optics (1) are designed to deflect the secondary light (8) into a radiation direction (10) of the lighting device (101) in order to produce a resulting light distribution (11). In order to use a passive safety system to reduce the potential risk from unconverted laser light (7) as far as possible without loss of power in the fault-free case, it is proposed that in a locally limited impact area (2) of the imaging optics (1), the laser light if the radiation converter (6) is no longer present (7), a microstructure (12) of a defined design is arranged, the design of the microstructure (12) being such that deflection angles of light (8, 7) hitting the impingement area (2) are selected such that the the microstructure (12) deflected light (13, 15) contributes to the generation of the resulting light distribution (11).

Description

The present invention relates to a lighting device for a motor vehicle. The illumination device comprises a laser light source for emitting laser light, a radiation converter, which contains a luminescent layer, in particular with phosphor, and an imaging optics. The radiation converter is designed to convert and fan out laser light emitted by the laser light source into broadband, in particular white, secondary light compared to the laser light. The imaging optics are designed to deflect the secondary light in a radiation direction of the illumination device in order to generate a resulting light distribution. The lighting device is used in particular as a headlight in a motor vehicle.

The invention further relates to a motor vehicle with at least one such lighting device. The motor vehicle preferably includes such a lighting device in the front area on each mounting side.

Laser light sources, especially semiconductor lasers, offer a number of advantageous properties, such as e.g. a comparatively small light-emitting surface, high radiation intensities, and the emission of largely collimated, narrow-band light beams. Optical systems for laser light can therefore be set up with smaller focal lengths than optical systems for less collimated light beams from, for example, incandescent lamps or light-emitting diodes (LEDs). The optical systems for laser light can therefore be implemented with a small installation space.

Problems with the use of laser light sources for lighting devices of motor vehicles arise in particular from the fact that lasers emit essentially coherent, monochromatic light or narrow-band light in a narrow wavelength range. Given the typical high radiation intensities of laser light sources, such light is potentially dangerous, especially for the human eye. This applies in particular to radiation powers of a few watts, as are desired in the field of motor vehicle lighting. For safety reasons, road users must not be dazzled in road traffic.

Another problem is that white mixed light is usually desired or required by law for the emitted light from a motor vehicle headlight. Measures must therefore be taken to convert it into suitable light.

For converting monochromatic light into polychromatic or white light, the use of radiation converters is known in the area of white light-emitting diodes (LEDs) or luminescence conversion LEDs. These usually have a luminescent layer, which in particular comprises phosphorus. In the case of luminescence, a physical system does not entirely or partially supply energy supplied from outside to its thermal energy, but is put into an excited state by the absorbed energy and emits light. If there is no activation process between energy absorption and emission, then one speaks of fluorescence; if an excited intermediate state can "freeze" the energy for a period of time, it is phosphorescence.

The light of a usually colored (e.g. blue or UV) light emitting LED stimulates the material of the luminescent layer to luminesce, whereby the radiation converter itself emits light of a different wavelength (e.g. yellow). In this way, at least part of the incident light of one wavelength range can be converted into light of another wavelength range. As a rule, a further portion of the incident light is scattered through the luminescent layer without conversion. The unconverted scattered light and the emitted light converted by luminescence can then additively overlap and lead e.g. to white mixed light.

When using the explained principle of luminescence conversion for motor vehicle headlights with a laser light source, the radiation converter is important in terms of safety. If the radiation converter is destroyed or e.g. removed from the beam path of the laser light source due to mechanical influences, vibrations or an accident, potentially dangerous laser light can escape from the headlight without conversion into the desired mixed light. In such accidents, measures must therefore be taken to avoid endangering road users from laser light. For this purpose, various active and passive safety systems are known from the prior art.

In active safety systems, a radiation detector continuously monitors during operation of the laser headlight whether the intensity of the laser light in the beam path after the radiation converter is within permissible (harmless) limit values. If this is not the case, appropriate countermeasures are taken to protect other road users, for example the power of the laser light source is reduced. Such an active system is, for example, from the DE 10 2012 220 481 A1 known. In passive safety systems, a loss of light is usually generated, for example by a beam trap, a diffusing element or a shading element. In the event of a fault (radiation converter damaged or removed), the loss of light ensures that this is potentially dangerous laser light is absorbed, scattered or shaded to such an extent that the risk potential for other road users is reduced. Such a passive system is, for example, from the DE 10 2013 016 423 A1 known. The problem with the passive systems, however, is that the absorption, scattering or shading of the light also occurs in the fault-free case when the radiation converter is fully functional, so that less useful light is available for generating the resulting light distribution. In the case of passive systems, the resulting loss in performance of the lighting device can amount to 15-30%.

The object of the present invention is therefore to increase the operational safety of a lighting device of a motor vehicle with a laser light source. In particular, a passive safety system for reducing the potential risk from unconverted laser light in the event of a fault is to be proposed, in which the loss of power in the fault-free case is as small as possible.

This object is achieved by a lighting device with the features of claim 1. Starting from the lighting device of the type mentioned at the outset, it is proposed in particular that a microstructure of a defined configuration is arranged in a locally limited area of incidence of the imaging optics, which is exposed to the laser light when the radiation converter is omitted, the microstructure being designed such that the deflection angle is from light hitting the impingement area are selected such that the light deflected by the microstructure contributes to the generation of the resulting light distribution.

The laser light source preferably has one or more laser diode semiconductor chips. An optically active element, in particular a lens or a reflector, can be arranged in the beam path between the laser light source and the radiation converter in order to bundle the laser light emitted by the laser light source as completely as possible onto the radiation converter. The radiation converter is preferably designed such that it has an approximately Lambertian radiation characteristic of the secondary light.

Unlike in the prior art, where only a scattering structure is provided in the impact area, which leads to an uncontrolled scattering of the incident light on all sides, so that a large part of the scattered light is not available for producing the resulting light distribution, is in the Invention arranged a microstructure of a defined configuration in the impact area. The microstructure is designed in such a way that the deflected light contributes to the generation of the resulting light distribution. All of the light deflected by the microstructure preferably contributes to the generation of the resulting light distribution, but at least half of the deflected light. For the most part, the deflected light lies within the resulting light distribution. The light falling on the impact area is expanded so that the hazard potential is significantly reduced in the event of a fault, but only to the extent that the deflected light still contributes to the generation of the light distribution. The light that is incident is thus redirected in a targeted manner by the defined microstructure. In this way, the hazard potential can be significantly reduced in the event of a malfunction with minimal impairment of the light distribution and without loss of light in the event of a fault.

According to an advantageous development of the invention, it is proposed that the imaging optics be designed as a reflector, which is preferably made of a thermoplastic, and the impact area is designed as part of a reflection surface of the reflector. The defined microstructure is preferably introduced into an injection molding tool for the reflector, for example by means of milling, and is thus formed at the same time as the reflector is produced as an integral part of the reflection surface in the area of impact. Alternatively, it would also be conceivable for the microstructure to be formed in the impact area of the reflection surface after the manufacture of the reflector, for example by machining with an embossing tool or with a laser beam. Manufacturing the reflector from thermoplastic has the advantage over a reflector made from thermosetting plastic that a metallization layer to be applied to the reflection surface after injection molding is very thin (for example <1.0 μm, in particular about 0.2 μm) and the dimensions of the previously formed microstructure largely retained even after coating. In contrast, one has on a reflective surface of a reflector made of thermosetting plastic to be applied after the injection molding, usually a thickness of several micrometers.

According to a preferred embodiment of the invention, it is proposed that the microstructure be designed such that a width and / or height of the deflection of the light striking the impact area and deflected by the microstructure corresponds to the total width and / or height of the resulting light distribution. According to this embodiment, the entire width and / or height of the light distribution is used to expand the light striking the microstructure, so that, on the one hand, the incident laser light is fanned out to such an extent that the hazard potential is significantly reduced, and on the other hand, the whole in the case of a failure Light striking the microstructure contributes to the light distribution.

In another embodiment, it would even be possible for the microstructure to be designed in such a way that a small part of the light striking the impact area and deflected by the microstructure extends beyond the width and / or the height of the resulting light distribution. In this case too, the deflected light lies predominantly within the resulting light distribution. The deflected light lying outside the light distribution can be used, for example, to implement a gentle runout of the light distribution towards the edges. The light that has been redirected by the microstructure into an area beyond the width and / or the height of the resulting light distribution is not simply lost unused, but can be used to soften the outflow of the light distribution to the outside, to illuminate an overhead area of a low-beam light distribution or for side illumination of peripheral areas (e.g. immediately in front of the vehicle or to the side of the road).

According to an alternative embodiment of the invention, it would also be possible for the microstructure to be designed in such a way that a width and / or height of the deflection of the light striking the impingement region and deflected by the microstructure is smaller than the width and / or the height of the resulting one Light distribution, in particular the light hitting the impingement area and deflected by the microstructure being deflected below a horizontal chiaroscuro limit of a dimmed light distribution. In the event of an accident, the laser light would thus be directed downward onto the roadway, which would result in an additional gain in safety.

According to another advantageous development of the present invention, it is proposed that the microstructure be configured in such a way that the deflection angles of the light striking the impingement area and deflected by the microstructure are different in the vertical and horizontal directions. It is particularly preferred if an opening angle of the light striking the impact area and deflected by the microstructure in the vertical direction is ± 5 ° (for high beam) or + 0 ° / -5 ° (for a light distribution with an upper chiaroscuro limit, for example low beam or fog light ) and in the horizontal direction is ± 45 °.

Advantageously, the deflection angles of the incident light caused by the microstructure are not the same over the entire incident area. In this way, an impairment of the light distribution in the case of a failure can be minimized. In this context, it is proposed in particular that the microstructure is designed in such a way that a vertical and / or horizontal first deflection angle of light striking a first sub-area of the impact area differs from a vertical and / or horizontal second deflection angle of striking a second sub-area of the impact area Light differs. According to this embodiment, the impingement area therefore has at least two subareas in which the microstructure is designed differently, so that the microstructure of these subareas generates different deflection angles of the incident light. Of course, it is conceivable that the impact area has more than two partial areas, each of which generates different deflection angles.

The microstructure is preferably designed in such a way that a first partial area is arranged in a center of the impact area and at least one second annular partial area surrounds the first partial area. In this embodiment, the partial areas are therefore concentric around the center of the impact area arranged. The shape of the partial areas or the area of incidence results from an intersection of the laser light (usually a cone with an elliptical base area) that strikes the area of incidence when the radiation converter is omitted and the area of the imaging optics, in the case of a reflector the reflection area (usually parabolic). The first partial area can be circular, elliptical or rectangular, for example, or have the shape of a conic section. The design of the microstructure in the partial areas of the impact area is such that different deflection angles of the incident light result in the partial areas.

In an alternative embodiment, the microstructure is configured in such a way that a first partial area is formed in a center of the impact area and a second partial area on an outer edge of the impact area, and that a vertical and / or horizontal deflection angle is based on the light hitting the impact area changes continuously from the first partial area to the second partial area. Advantageously, the vertical and / or horizontal first deflection angles generated by the microstructure in the center of the impact area are larger than the vertical and / or horizontal second deflection angles generated by the microstructure on the outer edge of the impact area, i.e. the light hitting the microstructure in the center of the impingement area is deflected more strongly than the light hitting the microstructure at the edge of the impingement area. In this context, it is very particularly preferred if the microstructure is designed in such a way that the center of the impingement area lies where an intensity profile of the laser light striking the impingement area when the radiation converter is omitted has its maximum. In this way it can be ensured that those beams of a laser light cone which have a particularly high intensity and therefore have a particularly high risk potential are deflected and expanded the most. On the other hand, those rays at the outer edge of the laser light cone that have a lower intensity and therefore have a lower risk potential are deflected and widened less.

According to another advantageous development of the present invention, it is proposed that the microstructure have a waveform in a vertical and / or in horizontal direction has at least three, preferably at least five, mountains and a corresponding number of valleys. The waveform can in particular have a sinusoidal shape, a triangular shape, a sawtooth shape or any intermediate shape. Height differences between neighboring mountains and valleys are advantageously in the range of <100 μm, preferably of <50 μm, very particularly preferably of <10 μm. Distances between adjacent mountains or adjacent valleys, that is to say a wavelength of the microstructure, are preferably in the range of <10 mm.

It is further proposed that the microstructure comprises a waveform with first waves with peaks and valleys of a first wave structure and second waves with peaks and valleys of a second wave structure, the first and second waves overlapping and the wave structures being oblique or perpendicular to one another. This results in a microstructure that can deflect the incident light in a targeted manner in the horizontal and vertical directions with predetermined deflection angles. The wavelengths of the first and second waves are preferably of the same size.

According to another advantageous development of the present invention, it is proposed that the lighting device have active safety monitoring, which is designed to switch off the laser light source in the event of a defect in the radiation converter or to reduce its power. In such an active safety system, a long period of time (referred to here as dead time), for example in the range of 250 ms, elapses between the occurrence of an accident and the time until the countermeasures initiated after detection of the accident have an effect on protecting other road users. During this period, a risk to other road users cannot be excluded. In contrast, the passive safety system proposed according to the invention is effective immediately after the occurrence of an accident and ensures a reduction in the risk potential without a time delay. The passive safety system proposed according to the invention can thus supplement an existing active safety system in such a way that it is active during the dead time Safety system for an initial reduction of the hazard potential. The active safety system can then further reduce the risk potential.

Figur 1

ein Beispiel für eine erfindungsgemäße Beleuchtungseinrichtung;

Figur 2

ein Lichtmodul einer erfindungsgemäßen Beleuchtungseinrichtung in einem störungsfreien Fall in einem Vertikalschnitt;

Figur 3

das Lichtmodul aus Figur 2 in einem Störfall in einem Vertikalschnitt;

Figur 4

ein Lichtmodul einer aus dem Stand der Technik bekannten Beleuchtungseinrichtung mit beispielhaft eingezeichnetem Strahlenverlauf in einem Vertikalschnitt;

Figur 5

einen Auftreffbereich einer Abbildungsoptik eines Lichtmoduls einer aus dem Stand der Technik bekannten Beleuchtungseinrichtung in einem Vertikalschnitt;

Figur 6

einen Auftreffbereich einer Abbildungsoptik eines Lichtmoduls einer erfindungsgemäßen Beleuchtungseinrichtung in einem Vertikalschnitt;

Figur 7

ein Diagramm mit einem Intensitätsprofil eines im Störfall auf den Auftreffbereich treffenden Laserlichtkegels und mit einer ersten Kurve von durch die Mikrostruktur des Auftreffbereichs bewirkten Ablenkwinkeln;

Figur 8

ein Diagramm mit einem Intensitätsprofil eines im Störfall auf den Auftreffbereich treffenden Laserlichtkegels und mit einer zweiten Kurve von durch die Mikrostruktur des Auftreffbereichs bewirkten Ablenkwinkeln; und

Figur 9

ein Beispiel für ein diskretes Streuelement einer im Auftreffbereich einer Abbildungsoptik einer erfindungsgemäßen Beleuchtungseinrichtung ausgebildeten Mikrostruktur;

Figur 10

ein erstes Beispiel einer im Auftreffbereich einer Abbildungsoptik einer erfindungsgemäßen Beleuchtungseinrichtung ausgebildeten Mikrostruktur in Wellenform;

Figur 11

ein zweites Beispiel einer im Auftreffbereich einer Abbildungsoptik einer erfindungsgemäßen Beleuchtungseinrichtung ausgebildeten Mikrostruktur in Wellenform;

Figur 12

ein anderes Ausführungsbeispiel eines Lichtmoduls einer erfindungsgemäßen Beleuchtungseinrichtung in einem Störfall in einem Vertikalschnitt; und

Figur 13

noch ein anderes Ausführungsbeispiel eines Lichtmoduls einer erfindungsgemäßen Beleuchtungseinrichtung in einem Störfall in einem Vertikalschnitt.

Further features and advantages of the present invention are explained in more detail below with reference to the figures. Show it:

Figure 1

an example of a lighting device according to the invention;

Figure 2

a light module of a lighting device according to the invention in a trouble-free case in a vertical section;

Figure 3

the light module Figure 2 in an accident in a vertical section;

Figure 4

a light module of a lighting device known from the prior art with an example drawn beam path in a vertical section;

Figure 5

a striking area of an imaging optics of a light module of a lighting device known from the prior art in a vertical section;

Figure 6

an impact area of an imaging optics of a light module of an illumination device according to the invention in a vertical section;

Figure 7

a diagram with an intensity profile of a laser light cone striking the impact area in the event of a fault and with a first curve of deflection angles caused by the microstructure of the impact area;

Figure 8

a diagram with an intensity profile of a laser light cone striking the impact area in the event of a fault and with a second curve of deflection angles caused by the microstructure of the impact area; and

Figure 9

an example of a discrete scattering element of a microstructure formed in the area of incidence of an imaging optics of an illumination device according to the invention;

Figure 10

a first example of a microstructure in the form of a wave formed in the area of incidence of an imaging optical system of an illumination device according to the invention;

Figure 11

a second example of a microstructure in the form of a wave formed in the area of incidence of an imaging optical system of an illumination device according to the invention;

Figure 12

another embodiment of a light module of a lighting device according to the invention in the event of a fault in a vertical section; and

Figure 13

yet another embodiment of a light module of a lighting device according to the invention in the event of a fault in a vertical section.

In Figure 1 A lighting device according to the invention for motor vehicles is designated in its entirety with reference number 101. In the example shown, the lighting device 101 is designed as a headlight. The lighting device 101 comprises a housing 102, which is preferably made of plastic. In a light exit direction 103, the headlight housing 102 has a light exit opening which is closed by a transparent cover plate 104. The cover plate 104 is made of colorless plastic or glass. The disk 104 can be designed as a so-called clear disk without optically effective profiles. Alternatively, the pane 104 can be provided, at least in some areas, with optically active profiles (for example cylindrical lenses or prisms) which scatter the light passing through, preferably in the horizontal direction.

In the example shown, two light modules 105, 106 are arranged inside the headlight housing 102. The light modules 105, 106 are arranged to be fixed or movable relative to the housing 102. A dynamic cornering light function can be implemented by moving the light modules 105, 106 relative to the housing 102 in the horizontal direction. When the light modules 105, 106 move about a horizontal axis, that is to say in the vertical direction, headlight range control can be implemented. Of course, more or less than the two light modules 105, 106 shown can also be provided in the headlight housing 102. At least one of the light modules 105, 106 has a laser light source and the passive safety system proposed according to the invention for reducing a hazard potential for people in the vicinity of the headlight 101 due to unconverted laser light.

A control unit 107 is arranged in a control unit housing 108 on the outside of the headlight housing 102. Of course, the control device 107 can also be arranged at any other point on the lighting device 101. In particular, a separate control device can be provided for each of the light modules 105, 106, wherein the control devices can be an integral part of the light modules 105, 106. Of course, the control unit 107 can also be arranged remotely from the lighting device 101, for example in the engine compartment of the motor vehicle. The control device 107 is used to control and / or regulate the light modules 105, 106 or partial components of the light modules 105, 106, such as light sources of the light modules 105, 106. The control of the light modules 105, 106 or the partial components by the control device 107 takes place via connecting lines 110 which in Figure 1 are only represented symbolically by a dashed line. The light modules 105, 106 can also be supplied with electrical energy via the lines 110. The lines 110 are led from the interior of the lighting device 101 through an opening in the headlight housing 102 into the control unit housing 108 and are connected there to the circuit of the control unit 107. If control units are provided as an integral part of the light modules 105, 106, the lines 110 and the opening in the headlight housing 102 can be omitted. The control unit 107 comprises a plug element 109 for connecting a connecting cable to a higher-level control unit (for example in the form of a so-called body controller unit) and / or an energy source (for example in the form of the vehicle battery).

The invention is explained below using the light module 105 with reference to FIG Figures 2 to 4 , 6 to 8 such as 12 and 13 explained in more detail. However, the statements can also apply to the light module 106. The light module 105 has a laser light source 4 for emitting laser light 7, which comprises, for example, one or more laser diode semiconductor chips. Furthermore, the light module 105 has a radiation converter 6 in the beam path of the laser light 7 Contains luminescent layer, in particular with phosphorus. Finally, the light module 105 has an imaging optics 1, which in the example shown is designed as a reflector, which is in particular made of a thermoplastic. The radiation converter 6 is designed to convert and fan out laser light 7 emitted by the laser light source 4 into a broadband, in particular white, secondary light 8 compared to the laser light 7. The imaging optics 1 are designed to deflect the secondary light 8 into a radiation direction 10 of the illumination device 101 in order to generate a resulting light distribution 11.

A microstructure 12 of a defined configuration is arranged in a locally limited impingement area 2 of the imaging optics 1, which is exposed to the laser light 7 when the radiation converter 6 is omitted. The design of the microstructure 12 is such that deflection angles of light 7, 8 striking the impingement area 2 are selected such that the light 13 deflected by the microstructure 12 contributes to the generation of the resulting light distribution 11. In spite of the microstructure 12 on the imaging optics 1, in the trouble-free case (cf. Figure 2 ) practically all of the secondary light 8 is available for generating the light distribution 11, so that the light module 105 or the lighting device 101 is particularly efficient. In the event of an accident (cf. Figure 3 ), if the radiation converter 6 is omitted or defective, however, the microstructure 12 provides for sufficient expansion and fanning out of incident unconverted laser light 7 from a laser beam 14, so that a hazard potential for people in the vicinity is significantly reduced.

An optically active element 5 can be arranged in the beam path between the laser light source 4 and the radiation converter 6, which element is designed as a lens in this example. The optically active element 5 could also be designed as a reflector. It directs the laser light 7 onto the radiation converter 6. In the example, the laser light source 4, the optical element 5 and the radiation converter 6 are parts of a light source module 3. The radiation converter 6 preferably has an approximately Lambertian radiation characteristic with which it detects the secondary light 8 emits.

In Figure 3 A malfunction is shown in which the radiation converter 6 is damaged, so that at least a portion of the laser light 7 from the laser light source 4 hits the incidence area 2 of the imaging optics 1 unconverted and in a narrow beam 14, possibly even as a parallel beam. A fault can also occur if the radiation converter 6 is completely eliminated, in which case the entire laser light 7 in the narrow beam 14 or the parallel beam strikes the impingement area 2 of the imaging optics 1. The microstructure 12 deflects the incident laser light 7 of the beam 14 and fanned it out to such an extent that the hazard potential of unconverted laser light 7 for surrounding people is significantly reduced. After the deflection, the light rays 15 are still within the light distribution 11. This has the advantage that in the case of a fault-free operation (cf. Figure 2 ) almost all of the secondary light 8, in particular also the light 13 falling on the impingement area 2 and deflected by the microstructure 12, is available for generating the light distribution 11.

In one example, the entire width and / or height of the light distribution 11 is used to deflect the light 8 or 7 falling on the impingement area 2. However, it would also be conceivable for a small part of the light 13 or 15 deflected by the microstructure 12 to be deflected beyond the width and / or height of the light distribution 11. The microstructure 12 would then be shaped in such a way that the rays of the deflected light 13 or 15 in the vertical and / or horizontal direction have an opening angle which is greater than the opening angle α _V or α _{H of} the light distribution 11 (cf. Figure 4 ) goes out. This can further reduce the risk potential. In this case, the light 13 deflected in the fault-free case is also predominantly within the resulting light distribution 11. The light 13 deflected beyond the light distribution 11 can, for example, soften the outflow of the light distribution 11 to the outside, to illuminate an overhead area above one horizontal light-dark boundary of a dimmed light distribution 11 or for improved side illumination of areas laterally next to the road illuminated by the light distribution 11.

Furthermore, it would also be conceivable that a width and / or height of the deflection of the light 13 striking the impingement area 2 and deflected by the microstructure 12 is smaller than the width and / or the height of the resulting light distribution 11. that the light 13 striking the impingement area 2 and deflected by the microstructure 12 is deflected below the horizon or below a horizontal chiaroscuro limit of a dimmed light distribution 11 (for example low beam or fog light). In this way, the hazard potential could be further reduced by the fact that the deflected laser light 15 only shines down onto the road in the event of a fault.

That in the Figures 2 and 3rd The light module 105 shown is designed as a reflection module, the reflector 1 preferably having a paraboloid-like shape.

The design and function of the microstructure 12 is explained in more detail below for a vertical section. However, the statements apply in a corresponding manner to a horizontal section. If in the trouble-free case (cf. Figure 2 ) the entire reflection surface of the reflector 1 is illuminated with the secondary light 8, the reflector 1 generates the full light distribution or a full light distribution cone 11. The light distribution cone 11 has a vertical opening angle α _V in the far field (cf. Figure 4 ). The opening angle α can be different in the horizontal and vertical directions. For example, for a low beam, the opening angle is horizontally up to ± 45 ° and vertically up to ± 5 °.

If only a section 1 _{T of} a reflector 1 without a microstructure 12 (cf. Figure 4 ) considered, only a part 11 _{T of} the light distribution cone 11 is generated from the section 1 _T. The part 11 _{T of} the light distribution cone 11 then has only an opening angle α _VT , which is smaller than the opening angle α _{V of} the entire light distribution cone 11. This leads to the fact that in the event of a malfunction, in the unconverted laser light 7 in the narrow beam 14 from the Light source module 3 emerges, this laser light 7 only falls on the very small section 1 _{T of} the reflector 1 and is then deflected by the reflector 1 only into a cone 11 _T with a very small opening angle α _VT . Is in good approximation this is usually an almost parallel beam 16 (cf. Figure 5 ), which has a very high risk potential for bystanders due to the high intensities with regard to laser safety.

According to the invention, in section 1 _T , corresponding to the area of incidence 2, on the conventional reflection surface (cf. Figure 5 ) modulates the microstructure 12 (cf. Figure 6 ), which is designed so that the incident light 8; 7 is already widened by the section 1 _T not only into the section α _{VT of} the opening angle α _V , but preferably up to the full opening angle α _{V of} the light distribution 11. The light 8 incident on the section 1 _T ; 7 is thus deflected more strongly from the section 1 _T and the light 13 or 15 already leaves the section 1 _T or the impact area 2 with the full light distribution cone 11. The fact that the light 8; 7, however, is only widened up to the full opening angle α _{V of} the entire reflector 1, no secondary light 8 striking the impingement area 2 is lost due to uncontrolled scattering in the case of a fault, but still contributes to the generation of the light distribution 11.

The microstructure 12 preferably has a waveform (cf. Figure 6 ). The wavelength λ of the modulated microstructure 12, ie a distance from successive mountains 12.1 or valleys 12.2 of the structure 12, is preferably in the single-digit millimeter range. However, the wavelength λ of the microstructure 12 is also dependent on the focal length of the reflector 1. With a smaller focal length, the wavelength λ should also be chosen correspondingly smaller. Height differences h between neighboring mountains 12.1 and valleys 12.2 are preferably in the range of <100 μm, preferably of <50 μm, very particularly preferably of <10 μm. In a vertical and / or horizontal section, the impingement area 2 preferably has at least three, in particular more than five waves (each wave with a mountain 12.1 and a valley 12.2). The waveform of the microstructure 12 can in particular be a sine shape, a triangle shape, a sawtooth shape or any intermediate shape. The flanks of the waveform can be inclined almost at will. In a vertical and / or horizontal section, the rising and falling flanks of a shaft can also have different slopes. A pitch angle β of the flanks of a shaft with respect to that original course of the reflection surface without microstructure 12 (cf. Figure 5 ) is preferably <1 °, in particular approximately 0.25 ° (cf. Figure 6 ). As a result, the microstructure 12 can be worked into an injection molding tool for producing the reflector 1 without problems, preferably by milling.

Compared to a conventional scattering structure, the microstructure 12 has the advantage that the deflection of the incident light 8 is designed in a defined manner. Thus, a reflector 1 can also be provided with such a microstructure 12, which is provided to produce a partial high beam distribution as the resulting light distribution 11. A conventional scattering structure, for example in the form of a matting, could produce uncontrolled scattered light in the case of a fault, which would lead to glare for other road users in the dark area of the partial high beam distribution. With the microstructure 12, the secondary light 8 can be redistributed in a defined manner in the light distribution 11.

The microstructure 12 can also consist of a large number of discrete scattering elements 27 arranged next to and / or one above the other (cf. Figure 9 ), which, however, do not cause uncontrolled scattering of the incident light 8, but rather a targeted deflection of the light 8 onto certain areas of the light distribution 11. In Figure 9 an example of such a scattering element 27 is shown in the form of a cushion optic. It can be clearly seen that the scattering element 27 is neither symmetrical in a vertical section nor in a horizontal section. Approximately, the diffusing element 27 has a plateau 17 in the middle, with inclined side walls 18 producing a continuous (steady) transition between the remaining reflection surface 19 and the plateau 17.

Furthermore, it is conceivable for the microstructure 12 to have a waveform (cf. Figure 10 ) with first waves 20 with mountains and valleys of a first wave structure 21 and second waves 22 with mountains and valleys of a second wave structure 23. The first and second shafts 20, 22 overlap and the shaft structures 21, 23 run perpendicular to one another. Of course, the wave structures 21, 23 of the two shafts 20, 22 could also run obliquely to one another. It can be clearly seen that both waves 20, 22, but in particular the second Wave 22, have an asymmetrical course. Another example of a microstructure 12 with first and second waves, the wave structures 21, 23 of which are perpendicular to one another, is shown in FIG Figure 11 shown.

In a further embodiment of the invention, it would be conceivable that the lighting device 101 is already equipped with an active safety system for reducing the risk potential from unconverted laser light 7, which reduces the power of the laser light source 4 in the event of a fault, in particular completely switches off the laser light source 4. However, such a security system only has a finite response time, which can be in the range of approximately 250 ms. Within this so-called dead time, in which the active safety system has not yet been able to reduce the laser light source 4 to reduce the hazard potential, there is already a hazard potential due to unconverted laser light 15 at a certain distance in front of the vehicle. The human eye also only activates a protective mechanism (for example, by closing the eyes) after a response time of around 250 ms. The human eye cannot react quickly enough to hazards caused by unconverted laser light 15 within the first 250 ms after the occurrence of an accident. Therefore, immediately after an accident occurs, it is particularly important to reduce the hazard potential as quickly as possible. Here, the passive safety system proposed according to the invention can make an important contribution, since it is fully operational immediately after the accident occurs and has no dead time. The microstructure 12 already reduces the hazard potential to a sufficiently safe level during the dead time of the active safety system and the reaction time of the human eye.

In this case, the microstructure 12 is preferably designed in such a way that it reduces the hazard potential that arises in the period between the occurrence of a fault and the active power reduction of the laser light source 4 to a sufficiently safe level. If, for example, the active safety system reduces the risk distance from 200% to 150%, the microstructure 12 only has to reduce the risk from 150% to 100%. Thus, the deflection or expansion of the light rays on the Striking area 2 striking light 8; 7 are smaller, the flanks of the microstructure 12 can be designed to be less steep. This has advantages for the manufacturability and the service life of the injection molding tool from which the reflector 1 is produced, since the structure corresponding to the microstructure 12 in the tool wears less and the milling radii are simpler.

A safety distance, which a person should keep from the headlight 101 in the event of a malfunction, in order to avoid endangering the person or their eyes from unconverted laser light 15, is theoretically around 30 m, for example, without any safety system. In practice, due to optical effects in the headlight 101 (for example caused by reflection, deflection, absorption at diaphragms or other optical elements in the headlight), there is a safety distance of 20 m. Thanks to an active safety system, the safety distance can be reduced to, for example, 10 m (for example, within the dead time of the active system). Thanks to the microstructure 12, the safety distance can be reduced again to, for example, 5 m.

Based on Figures 7 and 8 a further embodiment of the invention is explained in more detail. It can be clearly seen that the height h of the microstructure 12 or the size of the deflection angle (curve 25) correlates with an intensity profile 24 (profile of the light intensity) of the laser beam or laser light cone 14 in the event of a fault. The deflection angles 25 directly result in the design or shape of the microstructure 12 to be modulated onto the reflection surface. An opening angle of the laser light cone 14 is plotted on the x-axis and strikes the impingement area 2 of the reflector 1 in the event of a fault. The normalized intensity values of the laser light cone 14 are plotted on the left y-axis and the values for the deflection angle of the microstructure 12 are plotted on the right y-axis. It can be clearly seen that the laser light cone 14 has the highest intensity (normalized to 1) in a central region at 0 ° and consequently the microstructure 12 also has the largest deflection angle of approximately +/- 1 ° in this region. In contrast, the intensities at the edge of the laser light cone 14 are relatively low (towards zero), which is why smaller deflection angles of approximately +/- 0.2 ° are also realized there. As a result, the necessary strong deflection angles can be realized in the central region of the laser light cone 14 in the event of a fault are, and these are weakened towards the edge, in order to further reduce the effects of the microstructure 12 on the light distribution 11 in the fault-free case.

In Figure 8 the deflection angles (curve 25) are only shown positively for simplification. Differences between the embodiments of the Figures 7 and 8 exist in particular in the course of an envelope 26 of the deflection angle curves 25, ie how the deflection angles change over the entire area of the impact area. The envelope 26 in Figure 7 consists essentially of two straight lines that intersect in the center (at 0 °) and also have their maximum of approximately +/- 1.0 ° there. The envelope 26 in Figure 8 has the shape of a curved curve with a maximum of about 0.2 ° in the center (at 0 °) and runs outward asymptotically towards a deflection of 0 °, whereby the deflection angles unite from an opening angle of approximately +/- 7 ° Have a value of about 0 °.

The invention - as described above and in the Figures 2 and 3rd shown - is based primarily on an optical system (so-called. reflection system), consisting of light source module 3 and reflector 1 for generating the light distribution 11. However, the principle can also be extended to combined reflection-projection systems, as described, for example, in the Figures 12 and 13 are shown. Such a system has a projection lens 28 which projects an image from an intermediate plane 29 onto the road in front of the vehicle. In this case, an expansion of the light cone 13 (in the case of a failure) or the beam cone 15 (in the event of a failure) in the intermediate image plane 29 is generated analogously by the microstructure 12. This expansion preferably takes place within the light distribution 11.

Alternatively, the widening of the light cone 13 or the beam cone 15 can be increased up to the maximum diameter of the lens 28 without loss of power occurring in the case of a failure. The light cone 13 generated by the microstructure 12 is then optimally so large that the projection lens 28 is completely illuminated, but not beyond the edge of the lens 28. The application can be used on projection systems with an aperture (preferably in or near the intermediate image plane 29) as well as for bi-function systems or high-beam modules be applied. For light modules 105 with a diaphragm in plane 29, the microstructure 12 can be designed in such a way that for greater security in the low beam case, a large part of the radiation 14 is directed onto the diaphragm and then only leaves the light module 105 in the high beam case.

Furthermore, the light output of the low beam in the case of a fault can be better maintained if the microstructure 12 preferably deflects the incident light 8 into the low beam area of the light distribution 11. It is also advantageous in a reflection projection module if the area of the microstructure 12 is as large as possible in order to generate the largest possible spread of the light cone 13 or the beam cone 15 in the light distribution 11 and to still shine through the lens 28. Ideally here would be the light source module 3, as in Figure 13 shown, slightly tilted. Then, in the event of a fault, the beam cone 14 has already opened further before it hits the reflector 1 or the deflection area 2 with the microstructure 12.

Claims (17)

Lighting device (101) for a motor vehicle, comprising a laser light source (4) for emitting laser light (7), a radiation converter (6) which contains a luminescent layer, in particular with phosphorus, and an imaging optics (1), the radiation converter (6 ) is designed to convert and fan out laser light (7) emitted by the laser light source (4) into broadband, in particular white, secondary light (8) compared to the laser light (7), and the imaging optics (1) is designed to form the secondary light (8 ) to deflect in a radiation direction (10) of the lighting device (101) in order to generate a resulting light distribution (11),
characterized in that
A microstructure (12) of a defined configuration is arranged in a locally limited impingement area (2) of the imaging optics (1), which is exposed to the laser light (7) when the radiation converter (6) is omitted, the configuration of the microstructure (12) being such that deflection angles of light (8, 7) striking the impingement area (2) are selected such that the light (13, 15) deflected by the microstructure (12) contributes to the generation of the resulting light distribution (11). Lighting device (101) according to claim 1,
characterized in that
the imaging optics (1) as a reflector, which is preferably made of a thermoplastic, and the impingement area (2) as a part (1 _T ) of a reflection surface of the reflector. Illumination device (101) according to claim 1 or 2, characterized in that the microstructure (12) is designed such that a width and / or height of the deflection of the light impinging on the impingement area (2) and deflected by the microstructure (12) 13, 15) corresponds to the entire width and / or height of the resulting light distribution (11). Illumination device (101) according to Claim 1 or 2, characterized in that the microstructure (12) is designed in such a way that a small part of the light (13, 15) which strikes the impingement area (2) and is deflected by the microstructure (12) the width and / or the height of the resulting light distribution (11) goes beyond. Illumination device (101) according to claim 1 or 2, characterized in that the microstructure (12) is designed such that a width and / or height of the deflection of the light impinging on the impingement area (2) and deflected by the microstructure (12) 13, 15) is smaller than the width and / or the height of the resulting light distribution (11), in particular the light (13, 15) that strikes the impingement area (2) and is deflected by the microstructure (12) below a horizontal chiaroscuro limit dimmed light distribution is deflected. Illumination device (101) according to one of the preceding claims, characterized in that the microstructure (12) is designed in such a way that the deflection angle of the light (13, 15) incident on the impingement area (2) and deflected by the microstructure (12) is vertical and horizontal direction are different. Illumination device (101) according to Claim 6, characterized in that the microstructure (12) is designed such that an opening angle of the light (13, 15) which strikes the impact region (2) and is deflected by the microstructure (12) in the vertical direction to to ± 5 ° or + 0 ° / -5 ° and in the horizontal direction up to ± 45 °. Illumination device (101) according to one of the preceding claims, characterized in that the microstructure (12) is designed such that a vertical and / or horizontal first deflection angle of light (13, 15) striking a first partial region of the impingement region (2) distinguishes from a vertical and / or horizontal second deflection angle of light hitting a second partial region of the impact region (2). Lighting device (101) according to one of the preceding claims, characterized in that the microstructure (12) is designed such that a first partial area is arranged in a center of the impact area (2) and at least a second annular partial area surrounds the first partial area. Lighting device (101) according to one of the preceding claims, characterized in that the microstructure (12) is designed such that a first partial area is formed in a center of the impact area (2) and a second partial area on an outer edge of the impact area (2) , and that a vertical and / or horizontal deflection angle of light impinging on the impingement area (2) changes continuously starting from the first partial area to the second partial area, the vertical and / or horizontal first deflecting angle being greater in the first partial area than the vertical one and / or horizontal second deflection angle in the second partial area. Illumination device (101) according to one of the preceding claims, characterized in that the microstructure (12) is designed such that a center of the impingement area (2) is located where an intensity profile (24) of the radiation converter (6) is eliminated when the radiation converter (6) is omitted Impact area (2) striking laser light (7) has its maximum. Lighting device (101) according to any one of the preceding claims, characterized in that the microstructure (12) comprises a waveform with mountains (12.1) and valleys (12.2), height differences (h) between neighboring mountains (12.1) and valleys (12.2) in Range of <100 microns, preferably <50 microns, most preferably <10 microns. Lighting device (101) according to one of the preceding claims, characterized in that the microstructure (12) comprises a waveform with mountains (12.1) and valleys (12.2), distances between neighboring mountains (12.1) or neighboring valleys (12.2), i.e. a Wavelength (λ) of the microstructure (12) are in the range of <10 mm. Lighting device (101) according to one of the preceding claims, characterized in that the microstructure (12) has a wave shape with at least three, preferably at least five, peaks (12.1) and a corresponding number of valleys (12.2) in the vertical and / or in the horizontal direction. having. Lighting device (101) according to one of the preceding claims, characterized in that the microstructure (12) is a waveform with first waves (20) with peaks and valleys of a first wave structure (21) and second waves (22) with peaks and valleys of a second wave structure (23), wherein the first and second shafts (20, 22) overlap and the wave structures (21, 23) run obliquely or perpendicular to each other. Lighting device (101) according to one of the preceding claims, characterized in that the lighting device (101) has an active safety monitoring system which is designed to switch off the laser light source (4) in the event of a defect in the radiation converter (4) or to reduce its power. Motor vehicle comprising at least one lighting device (101) according to one of the preceding claims.

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