EP1201985A2 - Lighting system, in particular for motor vehicles and method of generating a light beam having a predetermined shape - Google Patents

Abstract

The system has at least one light source (12), preferably a high intensity discharge lamp, especially a low voltage xenon lamp, a collector (14) and at least one separator (16) of light conducting material, whereby each separator has at least one specially shaped light outlet surface for radiating the light fed into the separator as a light beam of defined shape.

Description

The invention relates to a lighting system, in particular for motor vehicles, and a Process for producing a light beam of the desired shape.

Lighting systems and corresponding methods for generating light beams are known for a long time and in the most diverse form. All corresponding lighting systems Common to the method and method is that a light source is used to generate light which then is bundled by different optical means so that the light bundle the desired shape. In the automotive field, there have been light sources in particular halogen incandescent lamps and increasingly gas discharge lamps in recent years, especially low-voltage gas discharge lamps such. B. so-called MPX lamps (micro power xenon lights) prevailed. The discharge lamps point big compared to incandescent lamps in terms of their life and performance Advantages, however, the arc generated by them has in contrast to one Incandescent lamp filament no exact limitation and is therefore optically and lighting technology more difficult to handle.

To form the desired light bundle from the light generated by the light source are known parabolic reflectors that point the light source directly to the project the illuminating surface onto the road in motor vehicles. The final bundle build-up by a diffuser, usually a combination of Prism and cylindrical lens arrays, which the lighting system closes to the front reached. In addition, projection systems are known in which an elliptical Reflect the light source a few centimeters away from the lamp maps. Near this level there is a sheet of automotive headlights as mechanical aperture, which is specially shaped to a required for the low beam Generate light-dark edge. A projection lens forms this aperture and the light source image on the road. This principle of bundle creation can be very Contrasting light-dark edges produce, however, a clear color fringe exhibit.

An improvement in the bundle properties is achieved through the use of so-called complex shape or open space reflectors. The geometry of the reflector is in small segments calculated individually due to their effect on the headlight bundle. This creates a reflector geometry that of classic rotating surfaces (elliptical or parabolic) deviates. With complex-shape reflectors it is with headlights possible with halogen light bulbs, without a dimming cap a sufficiently high one To achieve contrast at the light-dark edge. Thanks to the improved reflector geometry can dispense with a lens for influencing the beam when using such reflectors become. In this case, a clear cover plate is sufficient.

In the known lighting systems with large-aperture reflectors that light Collecting from the light source and thus building up the headlight bundle are very demanding to the positioning of the light source in the reflector. This happens especially when using gas discharge lamps as a light source, since the arc in the Compared to the filament in incandescent lamps has no sharp limit.

Due to the increasing demands on bundle quality, the requirements also increase the positioning of the light source in the reflector. Since this light source in Exact positioning poses a problem as a rule, if it is to be held interchangeably On the one hand, the lamps should be replaced in a simple and quick manner on the other hand, they must be securely and precisely attached and the used ones Fastening devices must be able to be manufactured at economically reasonable costs. This leads to manufacturing tolerances in the fastening devices used in each case limit the efficiency and light output of the overall system.

Based on this, the object of the invention is an illumination system in particular for motor vehicles and a method for producing a light beam Specify the desired shape, in which the exact positioning of the light source relative to the other optical components only a little influence on the Light output and the efficiency of the overall system or on the generation of the desired light beam.

The object is achieved by a lighting system, in particular for motor vehicles, the at least one light source, preferably in the form of a high-power discharge lamp (HID - high-intensity discharge lamp) in particular a low-voltage xenon lamp (MPXL - Micro-Power-Xenon-Light), the light source at least partially surrounding collector for collecting and forwarding the generated by the light source Light to at least one separator and at least one separator made of light-conducting Material comprises, wherein each separator via at least one specially shaped light exit surface for emitting the light directed into the separator as a light beam defined form.

The configuration according to the invention has a number of advantages. It will be like this possible, e.g. clearly limited required in the automotive field with low beam Light-dark edge due to appropriate design of the collector without absorption generate and then this edge by means of one or preferably several separators map. So far, however, the edge has been created by diaphragms, which are part of the hide generated light and thus the efficiency of corresponding lighting systems reduce unnecessarily. In a lighting system according to the invention in contrast, practically all of the light generated by the light source or sources for illumination be used, so that there is a very high efficiency.

Another great advantage of the configuration according to the invention is that it is very compact lighting systems can be realized, their overall length compared to conventional Systems is greatly reduced.

In a particularly preferred embodiment, the light source, collector and Separator (s) arranged in such a way that a so-called "intertwined beam path" results. For this purpose, the separator (s) and collector are arranged relative to one another in such a way that that part of the image of the light source generated by the collector in the area of the entrance pupil each separator lies. In this way, separation from advantageously takes place Illumination beam path (the image of the light source) and imaging beam path (the image of the object to be imaged, here the collector), whose light exit surface (s) can produce sharp light-dark edges.

If the light-dark edge is close to or in a pupil of the illuminating beam path, a non-exact alignment of the light source has little or no effect on the Contrast of the light-dark edge. The function of the known condensers or According to the invention, the collector optics in its exit surface there are sharp edges that are considered an object.

In particular, the size of the light source has practically no influence in this embodiment on the aperture in the headlight bundle, but only on the diameter of the Separators. In contrast, the headlights that have been on the market so far for motor vehicles, the light source is mapped directly onto the road, i.e. each Segment of the reflector creates a sharp image of the filament or the arc the roadway.

Is the diameter of the separators larger or at least equal to the size of the virtual one Light source image, the beam is not cropped, and the efficiency of the Lighting system is very high.

By decoupling the shape of the emitted light beam from its size and orientation the filament can be the aperture of the light rays emanating from the light source can be kept small without the usual lighting problems As a rule, a small aperture is desired, since the aperture size of the Is directly dependent on the collector if the collector is to work with very high efficiency. Light sources with an aperture of less than 60 °, preferably between 20 °, can be used and 40 ° and below can be used.

The intertwined beam path also increases the efficiency when using conventional discharge lamps, since the light that is in the so-called salt puddle is scattered, which occurs during the operation of such discharge lamps forms. Due to the intertwined beam path, the bow no longer has to be sharp in the Headlight bundles are imaged, so that a stronger scatter of light only has little influence on the bundle.

If a discharge lamp with a lamp bulb is to be used as the light source discharge lamps with a cylindrical or sagging bulb shape in particular proven.

The collector is preferably designed as a solid component and consists of a transparent heat-resistant material, preferably made of glass. Depending on the used Light source, the collector can also consist of a light-conducting plastic, which can have weight advantages over glass. However, that leaves more common when used Gas discharge lamps generate great heat, only a few plastics as collector material seem suitable.

The collector preferably has an annular light exit surface, so that is advantageous with one and the same "standardized" collector shape by using different ones Separators many uses can be covered.

Depending on the shape of the desired light beam and purpose of use, it may be sufficient Collector just to arrange a separator. Especially for the generation of in the automotive field With the low beam desired light beam, however, it has become special proven, the light from the collector on several, preferably six to ten separators to distribute and then the light beams emitted by the separators to form the Overlap the desired shape.

If the scattering of the light emerging from the separator (s) is desired, so For this purpose, the light exit surfaces of the separators can have a structure like a diffuser exhibit. This has the advantage of being on a separate spreading disc and thus one further material-air-material transition of light, always with light loss is connected, can be dispensed with.

Fig. 1

eine schematische Prinzipskizze eines in einem Gehäuse angeordneten Beleuchtungssystems mit Lichtquelle, Kollektor und Separatoren,

Fig. 2

einen Schnitt durch den Kollektor gemäß Fig. 1 entlang der Linie A-B in Fig. 3,

Fig. 3

einen Schnitt durch den Kollektor entlang der Linie C-D in Fig. 2,

Fig. 4

eine Prinzipskizze des verflochtenen Strahlengangs durch ein erfindungsgemäßes Beleuchtungssystem mit Lichtquelle, Kollektor und einen in Seitenansicht gezeigten Separator,

Fig. 5

den Strahlengang durch das Beleuchtungssystem gemäß Fig. 4, gesehen in einer gegenüber Fig. 4 um 90° um die Hauptabstrahlrichtung gedrehten Ansicht,

Fig. 6 - 10

verschiedene Ansichten eines erfindungsgemäß ausgebildeten Separators.

Further details and advantages of the invention emerge from the following purely exemplary and non-limiting description of an exemplary embodiment in conjunction with the drawing. Show it:

Fig. 1

1 shows a schematic diagram of an illumination system with light source, collector and separators arranged in a housing,

Fig. 2

2 shows a section through the collector according to FIG. 1 along the line AB in FIG. 3,

Fig. 3

3 shows a section through the collector along the line CD in FIG. 2,

Fig. 4

1 shows a schematic diagram of the intertwined beam path through an illumination system according to the invention with light source, collector and a separator shown in side view,

Fig. 5

4, seen in a view rotated by 90 ° relative to FIG. 4 about the main emission direction,

6-10

different views of a separator designed according to the invention.

FIG. 1 shows a lighting system, designated as a whole by 10 shown, the essential parts of a light source in the form of a discharge lamp 12 Collector 14 and a number of separators 16, which form a total separator, in a common housing 18 with a translucent front surface 20 is arranged are. The parts are in the housing 18 as well as one for operating the discharge lamp 12 necessary ballast 22 by means of corresponding, known per se Holding means 24 held in a suitable, possibly adjustable manner.

The collector 14 and the separators 16 are each solid components, so that the light is deflected and forming a light beam in contrast to the usual systems within transparent materials and the light from the light source to Leaving the lighting system largely not in air, but in a solid Medium moves.

In Figures 2 and 3, the collector 14 is shown in two views. Clearly visible is an essential feature of the invention that the great efficiency of an invention The lighting system contributes: the collector "encloses" the discharge lamp 12, more precisely the area in which the electrodes of the discharge lamp are arranged and in which the arc is formed when the lamp is in operation. The collector captures almost all of the generated light. For this purpose, a light entry surface 24 of the Collector designed such that it surrounds the discharge lamp 12 and its axial Limitation outside that occupied by the bulb of the discharge lamp 12 Range.

In the exemplary embodiment shown, the discharge lamp 12 is relative to the collector 14 arranged so that the electrodes of the lamp lie on a straight line that is essentially runs parallel to the direction of radiation of the desired light beam. One speaks therefore from an "axial burner position", in contrast to the so-called "transverse burner position", in which a part of the light generated by the burner directly in the direction of the desired light beam is emitted.

With the transverse burner position, part of the light must pass through a reflective surface to be directed in the desired direction. Forming a Beam of light from the resulting mixture of directly emitted and redirected However, light is difficult and requires an exact and therefore very complex Alignment of the burner relative to the reflector or collector. Therefore, in generally the axial burner position shown to be preferred.

With the axial burner position, no light is emitted in the direction of the desired one Illumination system to generate light beams emitted so that all the light must be influenced by the collector in order to be brought in the bundle direction. It is thus easier to generate a desired exit light distribution of the collector.

In this exemplary embodiment, the collector 14 has a radial aperture between about 15 ° and 25 ° and has a conical light entry surface facing the light source 24 and an annular light exit surface 26. A rotationally symmetrical construction the collector 14 advantageously allows different with the same collector Light beams, e.g. - when used in a motor vehicle headlight - a Generate bundles for right-hand traffic and for left-hand traffic. This enables one Particularly inexpensive manufacture of various headlight models based on the same collector. Only the separators then have to be replaced.

Depending on the shape of the collector, it may be useful to have the outside 28 of the collector 14 at least partially mirrored so as to ensure that the lamp 12 over the Light entry surface into the collector 14 light practically completely to the light exit surface 26 is deflected. The mirrored outside 28 of the collector 14 has the shape of an ellipsoid of revolution.

In principle, the collector can also be shaped so that the desired reflection also results on the outside by total reflection, but this allows at least partial Mirroring the outside a particularly compact design of the collector and thus a short overall length of the overall system.

The light exit surface 26 of the collector is shaped in such a way that when it is used as intended Operation of the lighting system emerging from the light exit surface 26 light bundle Have edges with sharp light-dark transitions. These are then created using of the separators, so that a light bundle of the desired is located in the overlay Form.

The inside 30 of the collector is shaped in such a way that it is in the correct assembly state of the collector can lead to total reflection relative to the light source. The Beam path is shown in Figures 4 and 5.

In FIGS. 4 and 5, the path of exemplary rays a, b, c, d and e is as intended Operation of the lighting system shown. It happens at the points 32 and 34 for total reflection, namely once at an interface of the collector 14 and once at an interface of the separator 16.

In the exemplary embodiment shown, the separators 16 use the aperture distribution of the Collector 14 ideal. The curvature of the light entry surface 36 and the light exit surface 38 of the separators 16 are each in the meridional section. The collector has in this Towards an aperture of approximately 15 °. The aperture is only perpendicular to this Degree, so that no imaging effect of the separators is necessary in this direction. In this way it becomes possible to add total reflection to the longitudinal surfaces of the separators use without disturbing the image of the high-contrast edges.

Because the high-performance light sources that are generally used are not just light in the visible range, but also in the UV range, for radiation protection reasons, but especially to increase the life of the separators advantageously made of a plastic such as Polymethyl methacrylate are produced and in As a rule, age by UV light, be appropriate, UV-absorbing in the beam path To take action.

Such measures can be applied to a wide variety of different applications optimally adapted ways are taken. For example, it is possible between light source 12 and collector 14 or between collector 14 and the separators 16 to put one or more UV filters. It may also be enough to use the collector made of a UV absorbing material such as B. glass. Light source 12, light entry and / or light exit surface of the collector and / or the light entry surface of the Separators can be provided with a UV-absorbing layer. Because coatings the light source due to the high temperatures that occur during operation Tend to flake off, as a rule, coatings on the light exit surface of the collector or to give preference to the light entry surface of the separators.

The separators 16 have a curved light entry surface 36 and a curved one Light exit surface 38. Each separator 16 is a solid component, advantageously made of plastic with good light-conducting properties, such as. B. Polymethyl methacrylate. Compared to glass, plastics have low temperature resistance on, however, the arrangement according to the invention has the great advantage of light source and thermally decouple separators so that the separators are only more moderate Are exposed to heat.

The lighting system according to the invention operates with reference to FIGS. 4 and 5 as follows: Light is generated by means of the light source 12. The light is turned on by the collector 14 collected and forming an intertwined beam path on the separators 16 directed. The collector not only fulfills the task of redirecting light, it also reduces and creates the aperture of the light emitted by the light source 12 a certain light distribution in its exit surface. At the edges of the light exit surface arise without absorption light bundles with the usually, for example Generation of low beam in the motor vehicle, desired sharp light-dark transitions.

The light bundles are then introduced into the separators 16 and by total reflection directed to the respective specially shaped light exit surfaces, where they are the separators leave and form the light beam of the desired shape in the overlay.

Numerous modifications and further developments are within the scope of the inventive concept possible, for example, based on the shape and number of separators Respectively. It is also conceivable for the collector and at least one of the separators train in one piece. The efficiency can be increased even further if the Light source integral part of the collector, if the lamp glass as a collector is trained. This makes it possible for the light-collecting element to be the burner completely encloses to capture more light from the arch. One as Collector designed lamp is more expensive than a conventional lamp, but because the Further development of gas discharge lamps for a greatly extended service life If the lamp is only rarely necessary, the also appears Use of such elaborately designed lamps makes economic sense.

Claims (11)

Lighting system, in particular for motor vehicles, comprising at least one Light source (12), preferably in the form of a high-power discharge lamp (HID - High-intensity discharge lamp), in particular a low-voltage xenon lamp (MPXL - Micro-Power-Xenon-Light), one that at least partially surrounds the light source (12) Collector (14) for collecting and forwarding the generated by the light source (12) Light to at least one separator (16) and at least one separator (16) light-conducting material, each separator (16) having at least one specially shaped Light exit surface (38) for emitting the light directed into the separator (16) as Light beam of a defined shape. Lighting system according to claim 1,
characterized in that the light source (12), collector (14) and separator (16) are arranged in such a way that an interwoven beam path results. Lighting system according to claim 2,
characterized in that the collector (14) and separator (16) are arranged such that at least part of the image of the light source (12) generated by the collector (14) lies in the region of the entrance pupil of the separator (16). Lighting system according to one of claims 1 to 3,
characterized in that the light source (12) is a light source with an aperture of less than 60 °, preferably between 20 ° and 40 °. Lighting system according to one of claims 1 to 4,
characterized in that the light exit surface of the collector (14) is shaped in such a way that the light bundles emerging from the light exit surface (26) of the collector (14) during operation of the lighting system have edges with sharp light-dark transitions. Lighting system according to one of claims 1 to 5,
characterized in that the collector (14) is designed such that the light collected by it is directed by reflection on the inner walls (28, 30) of the collector (14) to at least one light entry surface (36) of the at least one separator (16) , Lighting system according to one of claims 1 to 6,
characterized in that the light source (12) is part of the collector (14). Lighting system according to one of claims 1 to 7,
characterized in that a plurality of separators (16), preferably six to ten separators (16) are provided and are designed such that when the lighting system is operated as intended, a light beam of the desired shape is obtained by superimposing the light beams emitted by the separators (16). Lighting system according to one of claims 1 to 9,
characterized in that the at least one separator (16) is designed such that, in the intended assembly state, at least part of the light introduced into the separator (16) via the collector (14) is caused by total reflection (32, 34) to form a light exit surface (38) is redirected. Lighting system according to one of claims 1 to 10,
characterized in that, in the intended installation state, the length of the separator (16) or separators (16) and collector (14) measured in the main emission direction of the light emitted by the separator (s) (16) is between 80 mm and 200 mm, in a lighting system for use in the passenger car area, preferably between 80 mm and 120 mm. Lighting system according to one of claims 1 to 10,
characterized in that, in the intended assembly state, the diameter of the separator or all separators (16) measured transversely to the main emission direction of the light emitted by the separator (s) (16) is between 60 mm and 200 mm, in a lighting system for use in the area of passenger cars preferably between 60 mm and 100 mm.

Images