EP0791779A2 - Motor vehicle headlamp for dipped and main beam and lamp - Google Patents

Abstract

The headlamp unit has a rear reflector (2) with 2 segments (14,15) of different curvature, defining an optical axis (A), enclosing a dual filament light bulb (3). The main lamp filament (7) extends axially and is partially enclosed by a screening plate for screening an azimuth angle of between 100 and 140 degrees, for defining the illumination zone.

Description

The invention is based on a motor vehicle headlight for low and high beam with reflector and lamp according to the preamble of claim 1. Furthermore, the invention also relates to a lamp suitable for headlights according to the preamble of claim 11.

These are, in particular, motor vehicle headlights with an open space reflector and a lamp with two luminous elements and a metallic screen, hereinafter referred to as a shading device. The lamp is usually an incandescent halogen lamp.

The previously used concept of a motor vehicle headlight with reflector and lamp normally uses so-called H4 lamps, as are known for example from DE-OS 26 51 643. A low beam lamp and a high beam lamp are each axially arranged within the lamp bulb. The low-beam light fixture is embedded in a anti-glare cap in such a way that the cap forms almost a half-shell, that is to say azimuthally spans an angle of almost 180 °. The anti-dazzle device is pulled up at the base-side end of the dipped-beam lamp so that it shadows the high-beam lamp.

The basic principle of such lamps is described in detail in older applications, such as DE-OS 17 72 256 and DE-OS 15 39 371. Accordingly, the anti-dazzle device is responsible for achieving the light-dark boundary by projecting its side edges on the reflector. An asymmetrical illumination of the road is preferably sought, which is achieved in that one side of the anti-dazzle device is not pulled all the way up to the level of the dipped-beam lamp body, but ends approximately 15 ° below it, so that the angle spanned by the anti-dazzle device is only 165 ° ( DE-OS 15 89 242). In principle, the high beam filament can also be a transverse filament instead of an axial filament. In this mode of operation, in which usually only either the low beam or the high beam is active, the utilization of the reflector is restricted. The loss as a result Shading by the anti-dazzle device is in the order of 40% of the total solid angle in the case of the dipped beam. Conversely, only about 40% of the solid angle can be used for the high beam, while about 60% of the solid angle contributes in an uncontrolled manner to the illumination of the near field by scattering the light of the high beam in the part of the reflector intended for the low beam.

The associated reflector is usually composed of two paraboloid parts, see, for example, DE-OS 27 20 956. However, in some cases, open-space reflectors are also used, such as those used, among others. are described in DE-OS 38 08 086 and EP-A 282 100.

This previously known basic principle is a compromise of contradicting demands that cannot yet be optimally satisfied.

It is an object of the present invention to provide a motor vehicle headlight with reflector and lamp according to the preamble of claim 1, which allows a great deal of flexibility in the design of multifunctional headlights. This relates in particular to an optimal solution for the two functions low beam / high beam. In addition, the concept according to the invention is also suitable for modern lighting functions which are of variable design and meet special requirements.

It is a further essential object of the invention to provide a lamp which is particularly suitable for headlights.

These objects are achieved by the characterizing features of claims 1 and 11. Particularly advantageous refinements can be found in the dependent claims.

The motor vehicle headlight according to the invention consists of a reflector which defines an optical axis and a two-filament light bulb arranged therein, the first filament, hereinafter referred to as the main filament, being arranged axially and being partially surrounded by a metallic cap which acts as a shatter. The term axial in this context means that the helix lies within sufficiently narrow tolerances in the optical axis.

Apart from this, it is also necessary, as is known per se, for the main filament to be outside the axis of the lamp bulb. More precisely, it is located in the reflector below the piston axis. This prevents glare from mirror images.

The reflector consists of two segments which have different contour profiles, the first segment being optically essentially assigned to the main filament, while the second segment is optically operated exclusively by the second filament, hereinafter referred to as the secondary filament. At least the contour of the first segment is an open space contour, the principle of which is described, for example, in DE-OS 38 08 086 and EP-A 282 100. Reference is expressly made to these two writings.

The second segment of the reflector is also particularly preferably a free-space contour. In principle, however, another contour, for example a paraboloid contour, is also suitable.

The contour of the first segment is preferably optimized in such a way that it creates the light-dark boundary necessary for the dimming effect. The basic principle is not to create the cut-off line by imaging the edges of a dimming cap or a diaphragm, but by appropriately superimposing a large number of images of the main filament that acts as a dipped beam. The light-dark boundary is generated by the top edges of the helix images, which correspond to the bottom edge of the helix. However, it is not excluded to generate the cut-off line by separate means, such as an aperture.

The main coil is surrounded by the shading device in such a way that an azimuth angle of approximately 100 ° to 140 ° is shaded, as a result of which a shadow zone and an illumination zone are defined in relation to the main coil in the reflector. The shader is, as is known from the technology of anti-dazzle devices, arranged in such a way that it is arranged in the reflector below the main helix. However, since it does not create the cut-off line, its positioning and dimensions are less critical than in the case of a dimming cap.

The secondary helix is arranged in the reflector just below the optical axis, the offset (based on the center of the secondary helix) being between 0.25 times and twice the diameter of the secondary helix. An offset of approximately 0.5 times the diameter is preferred. The secondary helix can be arranged axially. However, the secondary helix is particularly preferably arranged transversely to the optical axis, because then the radiation characteristic of the secondary helix can be optimally matched to the two-part contour of the reflector. In particular, this means that only horizontal illuminant projections can be generated in the second reflector segment, which can be very easily converted into the desired light distribution for the remote lighting. In contrast, an axial secondary helix creates vertically lying helix patterns in the second reflector segment, which are less suitable for this classic application.

The spatial division of the two segments of the reflector is roughly matched to the two zones defined by the shader. This means that the first segment, which essentially processes the light from the main coil, is significantly larger than the second segment, which is served exclusively by the secondary coil. In plan view, both segments - for example, a circular reflector opening is assumed - cutouts that resemble pie pieces and together add up to a complete pie (corresponding to an azimuth angle of 360 °). The second segment is spanned by an azimuth angle that corresponds approximately to the azimuth angle of the shader. The azimuth angle of the second segment is preferably to be chosen to be somewhat smaller than that of the shading device, in particular up to 20% smaller, due to penumbra effects. It is typically about 10% smaller.

The shader is essentially located under the main helix. It is shaped so that the secondary helix is at least predominantly in the shadow zone. Its basic shape can be rectangular. However, it can also be chosen, for example, in a rough approximation as a spoon-like or coat-of-arms. In this case, it has a frontal tip, which is arranged between the secondary and main helix, two straight or curved side edges (approximately parallel to the main helix) and an end edge running transversely to the side edges or a blunt end tip.

The shading of the secondary helix is essentially caused by the frontal tip of the spoon or coat of arms. For this purpose, it can be bent up and / or extended.

The shading device can be an originally flat sheet metal part that is continuously concavely curved or in which flat sections are angled together. Such a shape is material-saving, easy to manufacture and low-reflection. The sheet metal part can also be concavely curved, in particular it is then shaped like a spoon or crest.

Seen from the origin of a polar coordinate system in the main helix, the side edges of the coat of arms span the azimuth angle from 100 ° to 140 °. The classic anti-glare cap, on the other hand, uses an azimuth angle of 165 ° for asymmetrical dimming.

Relative to a horizontal plane, which includes the main helix and which has its origin in the main helix, both side edges of the shader are clearly below the lower edge of the main helix. The azimuthal distance to this horizontal plane is preferably at least 20 ° at both side edges. The arrangement of the shader is advantageous symmetrical to this plane, so that the angular distance is the same on both sides. In contrast, in the classic anti-dazzle device, one side edge lies exactly in the horizontal plane, while the other side edge has an azimuthal distance of 15 ° from it.

In low beam operation, only the main filament is active together with the first reflector segment. There are several variants for high beam operation.

In a preferred embodiment, the radiation of the secondary filament falling into the shadow zone is used in a targeted manner with reflection on the second segment to generate an intense light bundle that can be used as an essential part of the remote lighting. A part of the radiation reaches the auxiliary filament in the non-covered for the secondary filament first reflector segment. This radiation does not provide any significant scattered radiation here, but is instead used in high beam operation as an additional contribution to side illumination. The low beam is switched off. In this embodiment, the electrical power of the secondary helix is approximately the same as that of the main helix. she can also be slightly larger, generally up to 40%. With a typical power of the secondary filament of 60 W, the luminous flux is about 200 lm.

In a second preferred embodiment, the main beam actually arises from the fact that the aforementioned light bundle and the radiation illuminating the sides, both of which are generated by the main beam, are superimposed on the low beam which is still in operation, ie the main and secondary filaments burn simultaneously in the high beam mode. For this reason, a relatively low power of the secondary helix is now sufficient, which only corresponds to between 20 and 80% of the power of the main helix. This fact underlines the high effectiveness of the headlight system presented here.

The lamp is advantageously a halogen incandescent lamp, since its dimensions are very small and its lifespan is very long.

As a point of reference for dividing the reflector area between the two segments, it can be assumed that the area share of the second segment assigned to the shadow zone in the total area of the reflector accounts for approximately 10 to 30%. With a secondary filament power of approximately 20 to 40 W, the useful luminous flux obtained from the second segment is preferably at least 80 lm. A typical power of the main coil is 50 to 70 W.

Accordingly , in a particularly preferred embodiment, the connection between the electrical connections of the two luminous elements is switched in such a way that the main filament acts as a low beam, while the main beam is formed from the superimposition of the light emitted simultaneously by the main filament and the secondary filament.

However, the novel concept presented here can also be used for other applications, in particular for applications combined under the term AFS (Advanced Frontlighting Systems), which are the subject of the Eureka project 1403. The light distributions which can be achieved in this way are distinguished by the fact that, using improved technology, they are better and / or more flexibly adapted to different traffic situations than the light distributions for low and high beams defined in rigid standards. One example is the adaptation of the cut-off line to the speed of travel.

The individual coils can be operated individually in the usual way or can also be connected together. In the latter case, three (or more) different operating modes can then be implemented. Instead of the usual light distributions, which correspond to the classic modes of operation "high beam" and "low beam", new types of light distribution can be realized particularly well, which correspond to modern modes of operation such as "city light", "country road light", "motorway light", "traffic sign lighting" and others. Such an operation is explained for example in DE-OS 41 24 374. The advantage of the technology presented here is in particular that it allows the number of headlights required for this to be kept low in modern lighting systems which offer a multitude of different functions.

Sliding screens and movable mirrors, for example, are suitable as further aids known per se for the purposes of AFS. In this case, the cut-off lines can also be realized by means of shutters.

• ein zylindrischer oder ähnlich geformter Kolben, der eine Kolbenachse definiert,
• ein Sockel, der eine Referenzachse definiert, die der optischen Achse eines Reflektorsystems entspricht,
• eine in der Referenzachse angeordnete Hauptwendel ist von einer metallischen Kappe als Abschatter umgeben, die einen Azimutwinkel von etwa 100° bis 140° abschattet,
• eine Nebenwendel ist außerhalb der Referenzachse angeordnet, wobei der Abstand zur Referenzachse zwischen dem 0.25-fachen und dem Zweifachen des Durchmessers der Nebenwendel beträgt,
• der Abschatter ist so geformt, daß auch die Nebenwendel zumindest überwiegend, bevorzugt vollständig, in der Schattenzone liegt.

Bevorzugt sind beide Wendeln entweder mit etwa gleicher Leistung ausgelegt oder sie sind so ausgelegt, daß die Leistung der Nebenwendel zwischen 20% und 80%, insbesondere etwa 50%, der Leistung der Hauptwendel entspricht.
Für die klassische Betriebsweise im Modus "Fernlicht" und "Abblendlicht" eignet sich besonders gut eine Lampe, bei der die Nebenwendel transversal zur Hauptwendel angeordnet ist, wie oben bereits erläutert.
Bei einer derartigen Konstellation läßt sich eine horizontale Ebene definieren, die die Hauptwendel einschließt und die parallel zur Nebenwendel verläuft und die ihren Ursprung in der Hauptwendel hat. Dabei ist es vorteilhaft, wenn, bezogen auf diese horizontale Ebene, beide Seitenränder des Abschatters deutlich unterhalb der Unterkante der Hauptwendel liegen. Bevorzugt besitzen beide Seitenränder mindestens 20° Winkelabstand zu dieser horizontalen Ebene.
Für einen Teil der oben diskutierten neuartigen Betriebsweisen kann es aber von Vorteil sein, wenn die Nebenwendel axial zur Hauptwendel angeordnet ist.Basically, in such applications, an axial secondary helix can be particularly advantageous if the associated reflector is very flat (in particular rectangular in shape).
However, lamps corresponding to the halogen incandescent lamp presented above can not only be used for motor vehicle headlights, but are generally suitable for reflector systems, in particular in headlights, with at least partial, but preferably complete, free-space contours. A halogen incandescent lamp which has the following features is particularly suitable:

• a cylindrical or similarly shaped piston that defines a piston axis,
• a base that defines a reference axis that corresponds to the optical axis of a reflector system,
• a main helix arranged in the reference axis is surrounded by a metallic cap as a shading device, which shadows an azimuth angle of approximately 100 ° to 140 °,
• a secondary helix is arranged outside the reference axis, the distance to the reference axis being between 0.25 times and twice the diameter of the secondary helix,
• the shader is shaped so that the secondary helix is at least predominantly, preferably completely, in the shadow zone.

Preferably, both coils are either designed with approximately the same power or are designed so that the power of the secondary coils corresponds to between 20% and 80%, in particular approximately 50%, of the power of the main coils.
A lamp in which the secondary filament is arranged transversely to the main filament is particularly suitable for the classic mode of operation in the "high beam" and "low beam" mode, as already explained above.
With such a constellation, a horizontal plane can be defined, which includes the main helix and which runs parallel to the secondary helix and which has its origin in the main helix. It is advantageous if, based on this horizontal plane, both side edges of the shader lie clearly below the lower edge of the main spiral. Both side edges preferably have an angular distance of at least 20 ° to this horizontal plane.
For some of the novel operating modes discussed above, however, it can be advantageous if the secondary helix is arranged axially to the main helix.

In such a constellation, a horizontal plane can be defined which includes the main helix and which has its origin in the main helix and which is perpendicular to a plane including the two helices. It is advantageous if, based on this horizontal plane, both side edges of the shader are clearly below the lower edge of the main helix, preferably at least 20 ° angular distance from this horizontal plane on both sides.

It is not excluded that, in the case of special requirements, the secondary helix is at an angle to the main helix and to the optical axis.

Depending on the orientation of the secondary helix relative to the main helix, it is possible that the secondary helix is not completely in the shadow zone of the shader. This applies in particular to a transverse or oblique arrangement. In general, however, at least 80%, preferably more than 95%, of the luminous surface of the secondary filament should lie in the shadow zone. In the case of a transverse secondary helix, a compromise must be made between a short helix, which is more favorable for shading reasons, and an elongated helix, which is more favorable for the light distribution of the main beam.

Figur 1

einen Scheinwerfer mit einer Zweifadenglühlampe mit transversaler Nebenwendel, teilweise im Schnitt

Figur 2

einen vergrößerten Ausschnitt aus Fig. 1 in Seitenansicht (Fig. 2a) und im Schnitt (Fig. 2b) sowie eine vereinfachte Draufsicht (Fig. 2c)

Figur 3

die mit dem Scheinwerfer von Fig. 1 erzielte Lichtverteilung, aufgeschlüsselt nach mehreren Komponenten (Fig. 3a bis 3c) und integral (Fig. 3d)

Figur 4

ein weiteres Ausführungsbeispiel einer Lampe mit axialer Nebenwendel, dargestellt als vergrößerter Ausschnitt entsprechend Fig. 2 in Seitenansicht (Fig. 4a) und Schnitt (Fig. 4b)

Figur 5

die mit dem Scheinwerfer von Fig. 4 erzielte Lichtverteilung, aufgeschlüsselt nach mehreren Komponenten (Fig. 5a bis 5c) und integral (Fig. 5d)

Figur 6

ein weiteres Ausführungsbeispiel einer Lampe mit einem planen Abschatter, dargestellt als vergrößerter Ausschnitt entsprechend Fig. 2 in Seitenansicht (Fig. 6a) und Schnitt (Fig. 6b)

The invention will be explained in more detail below with the aid of several exemplary embodiments. Show it:

Figure 1

a headlamp with a two-filament light bulb with transverse auxiliary filament, partly in section

Figure 2

an enlarged detail of Fig. 1 in side view (Fig. 2a) and in section (Fig. 2b) and a simplified plan view (Fig. 2c)

Figure 3

the light distribution achieved with the headlight of FIG. 1, broken down into several components (FIGS. 3a to 3c) and integral (FIG. 3d)

Figure 4

a further embodiment of a lamp with an axial secondary filament, shown as an enlarged detail corresponding to FIG. 2 in side view (FIG. 4a) and section (FIG. 4b)

Figure 5

the light distribution achieved with the headlight of FIG. 4, broken down into several components (FIGS. 5a to 5c) and integral (FIG. 5d)

Figure 6

a further embodiment of a lamp with a flat shading, shown as an enlarged detail corresponding to Fig. 2 in side view (Fig. 6a) and section (Fig. 6b)

1 schematically shows a headlight 1 with reflector 2 and halogen incandescent lamp 3. The reflector defines an optical axis A. The lamp 3 has a cylindrical bulb 4 which is squeezed on one side and carries a base 5 on the pinch. The end of the piston 4 remote from the base is rounded and provided with an absorption coating 6 known per se. A first filament forms the main filament 7 with an output of 50 W. It lies in the reference axis of the base, which coincides with the optical axis A of the headlight, being arranged somewhat below the bulb axis B (which is parallel to the optical axis) .

A second luminous element with an output of 25 W, which forms the secondary filament 8, is arranged transversely to the optical axis. The secondary helix 8 is placed between the base 5 and the main helix 7 just below the optical axis. The distance to the main coil 7 is 2 mm, the distance to the optical axis is 1 mm, based on the center of the coil. This offset against the optical axis corresponds to approximately 0.75 times the diameter of the secondary helix.

2a and 2b shows the geometric relationships in the lamp in an enlarged detail in side view and cross section. The coils 7 and 8 and a shading device 9 are usually fastened to power supply lines 17, which are fixed to a quartz beam 21. The shader 9 is arranged horizontally below the main coil 7. It is a concave curve Sheet metal part, which is shaped like a crest with a blunt tip 10, two side edges 11 and an end edge 16. The tip 10 of the shader 9 lies between the main and secondary helix. It is pulled up so far that it virtually completely shades the secondary helix 8, seen from the main helix 7. The distance of the shader 9 from the main helix 7 and its width, that is the distance between the side edges 11, is dimensioned such that, seen from the main helix, a shadow zone 12 is created which spans an azimuth angle of α = 120 °. Accordingly, the lighting zone 13 spans the remaining azimuth angle of 240 °. The shader 9 is arranged symmetrically to the vertical. Nevertheless, an asymmetrical light distribution is achieved because this is a property of the reflector contour.

Surprisingly, a constellation is actually possible here, in which the position of the two coils and the shader is coordinated with one another such that the width of the transverse helix 8 can be chosen to be smaller than the width of the shader, while at the same time the distance between the side edges of the shader and the main helix is chosen so that the azimuth angle α, seen from the main helix 7, causes the required shading of approximately 120 °.

The reflector contour shown schematically in FIGS. 1 and 2c consists of two segments 14 and 15, both of which are designed as open areas. The light from the main coil 7 is processed exclusively by the first segment 14 arranged at the top in the headlight, while the second segment 15 (shown hatched), which is at the bottom, specifically processes only light from the secondary coil 8. The secondary helix 8 is arranged in the headlight 1 so that it is just below the "focal volume" of the second reflector segment 15. (In the case of a paraboloid as the second reflector segment, the secondary helix is just below the focal point). In the plan view of FIG. 2c, the two segments 14 and 15 coincide approximately with the zones 12, 13 generated by the shading device 9. The azimuth angle β of the second segment spans approximately 110 °, that of the first segment the remaining azimuthal full angle (250 ° ).

In another exemplary embodiment, the headlight has a rectangular basic shape instead of a circular shape, for example with a width of 13 cm and a height of 10 cm.

In the low beam mode, only the main filament 7 is illuminated and, accordingly, only the first segment 14 is illuminated. The free-space contour of this first segment 14 produces the typical asymmetrical low-beam light distribution, which is shown in FIG. 3a, without additional aids such as a anti-glare cap. Lines of the same illuminance are shown. The sharp cut-off line is striking. The measurement was carried out on a measuring wall at a distance of 25 m. The detected horizontal angle is -30 ° to + 30 °, the vertical angle is -5 ° to + 5 °.

• Eine erste Komponente wird wieder durch die Abblendlichtverteilung gemäß Fig. 3a von der Hauptwendel 7 in Verbindung mit dem ersten Reflektorsegment 14 erzeugt.
• Eine zweite, für das Fernlicht wesentliche Komponente besteht aus einem schmalen, hellen Lichtbündel im Zentrum der Lichtverteilung, das durch die Nebenwendel 8 in Verbindung mit dem zweiten Reflektorsegment 15 erzeugt wird. Diese Komponente ist in Fig. 3b gezeigt.
• Hinzu kommt eine dritte Komponente, die sich dadurch ergibt, daß die Nebenwendel 8 auch das erste Reflektorsegment 14 beleuchtet. Auf diese Weise wird eine zusätzliche Ausleuchtung der Seitenbereiche gemäß Fig. 3c erreicht. Dieses Zusatzlicht dient zusammen mit dem Abblendlicht dazu, den durch das Lichtbündel des zweiten Segments erzeugten
  
  Tunneleffekt" zu beseitigen.

In the high beam mode, both the main coil 7 and the secondary coil 8 are illuminated, so that the high beam distribution is composed of several components:

• A first component is again generated by the low beam distribution according to FIG. 3a from the main coil 7 in connection with the first reflector segment 14.
• A second component, essential for the high beam, consists of a narrow, bright light bundle in the center of the light distribution, which is generated by the secondary filament 8 in connection with the second reflector segment 15. This component is shown in Fig. 3b.
• In addition, there is a third component which results from the fact that the secondary filament 8 also illuminates the first reflector segment 14. In this way, additional illumination of the side areas according to FIG. 3c is achieved. Together with the low beam, this additional light serves to generate the light generated by the light beam of the second segment
  
  Tunnel effect " .

The resulting high beam, which is shown in Fig. 3d, is the sum of these three individual components. What is striking is the very cheap, even high beam distribution, which gradually merges into the bright light beam in the center, and the high efficiency of the total luminous flux.

An arrangement with an axial secondary helix 18 is shown in FIGS. 4a and 4b. Otherwise, the same components correspond to the same reference numbers as in FIGS. 1 and 2. Here too, the secondary helix 18 is arranged approximately 1 mm below the optical axis. The distance between the mutually facing edges 19 and 20 of the main coil 7 and the secondary coil 18 is 1.5 mm. The shader 9 is in an analogous manner as in the previous embodiment arranged. The light distribution of such a lamp in a headlight similar to the first exemplary embodiment is shown by way of example in FIGS. 5a to 5d. The switching of the filaments again corresponds to the operating modes discussed in connection with FIG. 3. Accordingly, the low beam distribution (FIG. 5a), which is again generated by the main coil in cooperation with the first reflector segment, is practically identical to that of FIG. 3a. In cooperation with the second segment, however, the secondary filament now generates a light beam with large apron lighting (FIG. 5b). The side illumination is also less homogeneous and less wide (Fig. 5c). The resulting high beam (addition of the components from FIGS. 5a to 5c) is still superior to that of a conventional H4 headlight, but achieves a lower maximum illuminance than in the first exemplary embodiment.

• Separate Ansteuerung der Hauptwendel erzeugt über das erste Reflektorsegment eine Lichtverteilung, die sich für den Betriebsmodus "Stadtlicht" eignet. Ein verschiebbares Blendensystem ist in Höhe der Horizontalebene plaziert und wirkt als Abblendmittel.
• Bei zurückgeschobenem, also aus dem optischen Strahlengang entferntem Blendensystem erzeugt bei weiterhin separater Ansteuerung der Hauptwendel ein Abschatter eine Lichtverteilung, die sich für den Betriebsmodus "Landstraßenlicht" eignet.
• Bei zusätzlicher Inbetriebnahme einer transversalen Nebenwendel wird mittels des zweiten Reflektorsegments eine Lichtverteilung erzeugt, die sich für den Betriebsmodus "Abblendlicht für Autobahnen" eignet.
• Als Alternative wird (bei entsprechend optimierter Reflektorkontur) im Falle eines gemeinsamen Betriebs der beiden Wendeln (über beide Reflektorsegmente wie oben beschrieben) durch leichtes Kippen des Reflektors eine Lichtverteilung erzeugt, die sich für den Betriebsmodus "Verkehrszeichenbeleuchtung" eignet.

In general, the two basic types of lamps presented here can also be used for other reflector systems composed of two segments. The two segments of the reflector of a car headlight, for example, consist of open-space contours that enable the following light distributions:

• Separate control of the main filament generates a light distribution via the first reflector segment, which is suitable for the “city light” operating mode. A sliding panel system is placed at the level of the horizontal plane and acts as a screen.
• When the diaphragm system is retracted, that is to say removed from the optical beam path, while the main helix is still controlled separately, a shading device generates a light distribution which is suitable for the “country road light” operating mode.
• When a transverse secondary helix is additionally commissioned, a light distribution is generated by means of the second reflector segment, which is suitable for the “low beam for highways” operating mode.
• As an alternative (with a correspondingly optimized reflector contour), if the two coils are operated together (over both reflector segments as described above), a light distribution is generated by slightly tilting the reflector, which is suitable for the "traffic sign lighting" operating mode.

Finally, an exemplary embodiment of a halogen incandescent lamp with a transverse secondary filament 8 is shown in FIG. 6. The same reference numerals correspond to the same features as in the previous figures. A planar shading device 25 surrounds the axial main helix 7. It is composed of several sections 26 to 30 which connect to one another at an angle. Such a shading device is low in reflex and can be produced particularly easily from a rectangular sheet metal strip without any material waste. The azimuth angle α is 110 ° here.

In a further exemplary embodiment, in accordance with the explanation in connection with FIG. 3, only the main filament 7 is illuminated again in the low-beam mode, and accordingly only the first segment 14 is illuminated. The explanations above also apply here. In high beam operation, however, only the secondary filament is illuminated, so that the high beam distribution consists of only two components:

• A first component essential for the high beam consists of a bright light beam in the center of the light distribution, which by the Secondary helix 8 in connection with the second reflector segment 15 is produced. This component is again similar to that shown in Fig. 3b Light distribution, but it is not so narrow.
• In addition there is a second component which results from the fact that the secondary filament 8 also illuminates the first reflector segment 14. In this way, additional illumination of the side areas according to FIG. 3c is achieved in order to again generate that generated by the light beam of the second segment
  
  Tunnel effect " .

The resulting high beam, which is similar to the light distribution shown in FIG. 3d, is the sum of these two individual components.

Claims (17)

Motor vehicle headlight (1) for low and high beam, consisting of a reflector with two segments (2), which defines an optical axis (A), and a lamp (3) arranged therein with a bulb (4), which has two lamps (7 , 8), the first filament, hereinafter referred to as the main filament (7), is arranged axially and is partially surrounded by a sheet metal part acting as a shading device (9; 25), characterized by the following features: - The reflector (2) consists of two segments (14, 15) which have different contour profiles, the first segment (14) being optically assigned to the main filament (7), while the second segment (15) is optically assigned to the second filament , which is referred to below as a secondary helix (8), at least the contour of the first segment (14) being an open space contour, - The main coil (7) is surrounded by the shading device (9; 25) in such a way that an azimuth angle of approximately 100 ° to 140 ° is shaded, as a result of which a shadow zone (12) and an illumination zone (13) are defined, the secondary helix (8) is arranged below the optical axis (A), the offset being between 0.25 times and twice the diameter of the secondary helix, - The spatial division of the segments (14, 15) of the reflector is assigned to the two zones (12, 13) defined by the shader, - The shader (9; 25) is shaped so that the secondary helix (8) is predominantly in the shadow zone (12). Motor vehicle headlight according to claim 1, characterized in that the free-space contour of the first segment (14) is optimized in such a way that it generates the light-dark boundary necessary for the dimming effect. Motor vehicle headlight according to claim 2, characterized in that, with respect to a horizontal plane, which includes the main coil (7) and which has its origin in the main coil, both side edges (11) of the shader clearly below the lower edge of the main coil lie, and preferably have at least 20 ° angular distance to this horizontal plane on both sides. Motor vehicle headlight according to claim 1, characterized in that the second segment (15) of the reflector is a paraboloidal contour or an open space contour. Motor vehicle headlight according to claim 4, characterized in that the radiation from the secondary filament (8) falling into the shadow zone (12) is used specifically to generate a narrow and intense light beam which can be used as an essential part of the remote lighting. Motor vehicle headlight according to claim 1, characterized in that the secondary helix (8) is arranged transversely to the optical axis (A). Motor vehicle headlight according to claim 1, characterized in that the two light bodies (7, 8) are designed so that the power of the secondary filament (8) corresponds to between 20 and 140% of the power of the main filament (7). Motor vehicle headlight according to claim 1, characterized in that the lamp is a halogen incandescent lamp. Motor vehicle headlight according to claim 1, characterized in that the area portion of the second segment assigned to the shadow zone makes up about 10 to 30% of the total area of the reflector. Motor vehicle headlight according to claim 1, characterized in that the electrical connections of the two luminous elements are connected to one another in such a way that the main filament (7) acts as a low beam, while the main beam either from the light emitted by the secondary filament or from the superimposition of the main and A secondary filament is emitted simultaneously. Halogen incandescent lamp for use in a reflector system, in particular in a motor vehicle headlight, with at least a partial open space contour, characterized by the following features: a cylindrical or similarly shaped piston (4) which defines a piston axis, a base (5) which defines a reference axis which corresponds to the optical axis (A) of a reflector system, a main helix (7) arranged in the reference axis is surrounded by a metallic cap as a shading device (9; 25), which shadows an azimuth angle of approximately 100 ° to 140 °, a secondary helix (8; 18) is arranged outside the reference axis, the distance from the reference axis being between 0.25 times and twice the diameter of the secondary helix, - The shader (9; 25) is shaped so that the secondary helix is at least predominantly in the shadow zone. Halogen incandescent lamp according to claim 11, characterized in that the two filaments are designed so that the output of the secondary filament corresponds to between 20 and 140% of the output of the main filament. Halogen incandescent lamp according to Claim 11, characterized in that the secondary filament (8) is arranged transversely to the main filament (7). Halogen incandescent lamp according to Claim 13, characterized in that, with respect to a horizontal plane which encloses the main filament (7) and runs parallel to the secondary filament and which has its origin in the main filament, both side edges (11) of the shading device are clearly below the lower edge of the main filament lie, and preferably have at least 20 ° angular distance to this horizontal plane on both sides. Halogen incandescent lamp according to claim 11, characterized in that the secondary filament (18) is arranged axially to the main filament (7). Halogen incandescent lamp according to Claim 15, characterized in that, with respect to a horizontal plane which encloses the main filament (7) and which has its origin in the main filament and which is perpendicular to a plane including the two filaments, both side edges (11) of the shader lie clearly below the lower edge of the main helix, and preferably have an angular distance of at least 20 ° to this horizontal plane on both sides. Halogen incandescent lamp according to claim 11, characterized in that the shading device (25) is a flat, in particular angled or continuously bent, sheet metal part.

Images