DE20213911U1 - Headlights, in particular for motor vehicles - Google Patents

Description

S:\IB5DUP\DUPANM\2 002 0 9\01530 921-ALL0 958 8.doc

Applicant: Automotive Lighting Reutlingen GmbH Tübinger Str. 123

72762 Reutlingen

01530921

06.09.2002 ALA/KOJ

Title:

Headlights, especially for motor vehicles Description

06.09.2002 Automotive Lighting Reutlingen GmbH, 727 62 Reutlingen

Headlights, especially for motor vehicles Description

The invention relates to a headlight, in particular for motor vehicles, comprising at least one light source, wherein at least two transparent light-closing bodies are associated with one light source, which

Have a light coupling surface for the light of the at least one light source and a light coupling surface, and at least one lens which interacts with the light coupling surface of the light closure body and is arranged behind the light closure body in the light emission direction and images the light coupled out by the light closure body.

Such headlights are known, for example, from DE 41 39 267, which discloses a headlight for motor vehicles with the following features: at least two light sources in a headlight, which are designed as light exit surfaces of at least one light guide, a lens in the headlight, which images the light from all light exit surfaces, a transparent cover plate that closes the headlight, a light plate with a light-scattering optic that influences the width of the image, a prism that influences the height of the image and a movement device that moves the light plate or the prism into the beam path between the light exit surfaces and the lens.

The aim is to provide a headlight for motor vehicles which is simple and cost-effective to manufacture, makes the best possible use of the light produced and can easily produce different lighting functions using only one lens.

The disadvantage of such a headlight, however, is that in addition to the lens, a diffuser or a prism is required to generate the light distribution, which reduces the efficiency of the system by approx. 10%.

, It is therefore an object of the invention to provide a headlight with which different light distributions, e.g. low beam and high beam, can be realized, whereby no additional parts such as a diffuser or prism are required.

The invention solves this problem by means of a headlight in which different light distributions can be achieved by selecting at least one light-closing body, the cross-section of the at least one selected light-closing body and the number and alignment of the selected light-closing bodies relative to one another. In this way, the light distribution of, for example, a dipped lamp with a light/dark boundary with a horizontal component and a 15% rise and a spot for a maximum can be realized particularly easily by, for example, arranging three different light-closing bodies that provide different light images, for example a triangular and a rectangular and an oval one, relative to one another in such a way that the desired light distribution is achieved. By moving the light-closing bodies or adjusting them vertically and horizontally or defocusing them relative to the light source, the

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Light distributions can be changed in such a way that, for example, only a horizontal light/dark boundary can be achieved, a tourist solution can be implemented which, for example, enables switching from right-hand to left-hand traffic without the headlights dazzling oncoming traffic, and the light distribution can be increased in such a way that high beam illumination is achieved.

At least two, but in particular three or more light closure bodies can be provided for this purpose. With two light closure bodies, for example, a low beam distribution without a spot for the maximum can be achieved. By providing at least three light closure bodies, for example, one light closure body can ensure lighting below the horizontal light/dark boundary, which is essentially rectangular in shape, another light closure body can illuminate the 15% gradient of the lighting on the right-hand side of the road (in a right-hand traffic solution), and the third light closure body can also illuminate the light maximum, which is below the light/dark boundary on the driver's own lane.

LEDs in particular can serve as light sources, whereby the advantage here is that LEDs can be coupled with the light-closing bodies and can couple their light directly into them via the light-coupling surfaces of the light-closing bodies, since the heat development of LEDs is low

Alternatively, the use of a gas discharge lamp or a halogen lamp can be provided. In these cases, however, a glass fiber or a filter, in particular an infrared filter, will usually be arranged between the light source and the light closure body in order to protect the light closure body thermally. In these cases, it can be provided that each light closure body is assigned a glass fiber and/or a filter. However, a few glass fibers or filters can also be provided as light closure bodies and the glass fibers and/or filters can only be coupled together with the light closure body when required in such a way that the light from the glass fiber or filter is coupled into the light closure body. For example, the light closure body can be attached to a slider or a turntable and only moved in front of the end of a glass fiber or a filter and brought into interaction with it when light is to be emitted through the light closure body.

If each light-terminating body is connected to a glass fiber (also a light guide in general) or a filter, these can be firmly connected to each other, e.g. by an optical adhesive, so that no light loss occurs at the transitions.

The light source can be assigned a reflector to reflect the light

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to focus the light emitted by the light source. In particular, the light coupling surface of the light closure body, or if a glass fiber is connected in front of the light closure body, the light coupling surface of the glass fiber will then be located in the second focal point of the reflector. The light source itself is located in the first focal point of the reflector.

It can be provided that the light-closing body has a rectangular, triangular, round or oval cross-section to generate a corresponding light distribution. These cross-sections of the light-closing bodies are then imaged by the lenses arranged behind the light-closing bodies in the direction of light emission. If the glass fibers are arranged between the light source and the light-closing body, they can have a circular or rectangular cross-section, but any other cross-sections can also be provided. Conventional PES lenses from projection headlights on motor vehicles can be used as lenses, which are plano-convex, light-collecting and rotationally symmetrical. Flat lenses can also be used, or any other lenses that have a light image appropriate for the light distribution.

In particular, it is advantageous if the light-closing bodies and/or the lenses are movable relative to each other in the XY or Z direction, in particular vertically horizontally and defocusing to produce an adaptive light distribution.

For example, it can be provided that the individual light-closing bodies, particularly together with the lenses connected to them, but also just the light-closing bodies, are movable in the XY and Z directions. This allows the individual light distributions achieved by the various light-closing bodies to be moved against each other in such a way that they can be combined to form a different light distribution. In particular, movement in the Z direction can also be provided, whereby in this way an overly sharp light/dark transition of the light/dark boundary can be avoided. Sharp transitions can be softened by this defocusing movement of the light-closing body. In general, the light distribution can be shifted up and down by a vertical shift, and the light distribution can be shifted left or right by a horizontal shift. Finally, as already mentioned, sharp transitions can be softened by defocusing, so that in this way, for example, switching from low beam to high beam, but also an adaptive light distribution for cornering lights and a tourist solution, i.e. switching from right-hand or left-hand traffic to the other type of traffic, can be made possible. It can also be provided that a beam diaphragm is provided between the light closure body and the lens to switch the individual light distributions on and off. In this way, switching from low beam and vice versa, for example, can be implemented particularly easily, whereby

known assemblies can be used.

In particular, the beam diaphragms can be arranged between each closure body and each associated lens so that, for example - if three light distributions are provided - the three light distributions can be switched on and off individually.

The previously mentioned movement of the end bodies can be realized, for example, via a stepper motor that can move (shift and defocus) the end bodies in three different directions against each other.

If the end body is not glued to the end of the light guide, e.g. if a glass fiber is provided as the light guide, it can be provided that several light end bodies are arranged on a rotary-movable turntable and/or a translatory-movable slider, whereby various connection pieces can be coupled to the at least one light source by the movement of the turntable and/or the slider. In this way, if glass fiber arms are provided, the number of glass fiber arms for the adaptive light distribution can be reduced.

In particular, if fibre optic arms or other light guides are provided, these can unite in front of the light source to form a single arm, in particular tangentially, and only then do they merge in the course of their path to the light-terminating bodies.

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However, fiber optic arms are relatively expensive, so if they must be used to avoid thermal stress on the light termination bodies, it is advantageous to use as few fiber optic arms as possible.

For example, it can be provided that more light-terminating bodies are provided than fiber optic arms and only the light-terminating bodies that are necessary to achieve the desired lighting distribution are moved in front of the fiber optic arms so that light is coupled into them.

The light-closing bodies can be made of plastic, in particular PC or PMMA, but they can also be made of glass.

In order to ensure that there is a homogeneous light distribution at the end of the light terminating bodies, i.e. at their light output surface, and that no color or brightness spots occur, the length of the transparent light terminating bodies must be at least three times as long as the glass fiber diameter (light guide diameter), if the light terminating bodies are arranged behind a glass fiber (light guide).

According to an independently inventive embodiment, it can be provided that the light closure body at its in

The end pointing towards the light output surface has a thickening into which only rays with large initial angles reach, thereby achieving a brightness distribution which leads to a blurred light/dark boundary.

In general, the entire light-terminating body is imaged with a very sharp light/dark boundary, not just in places where it is desired, but along the entire contour. In order to create the light/dark boundary, the light-terminating bodies have specific cross-sections which, due to the simple shape of the light-terminating bodies, are generally imaged with the same brightness over their entire end surface, and therefore the lens images a sharp light/dark boundary over the entire outline during projection. The new and inventive cross-section of the terminating body is now thickened towards the end of the terminating body in the direction in which, for example, the light/dark boundary with the 15% increase is not to be created, but rather a sharp light/dark boundary is to be achieved in this area compared to the rest. This means that only rays with large angles of incidence can reach the thickened area, but rays with large and small angles of incidence can reach the area in which the 15% light/dark boundary is created. This allows a brightness gradient to be achieved, which is also projected further by the lens.

In particular, it can be provided that the thickening increases continuously in the direction of the coupling-out surface.

i,} Further advantages and features of the invention emerge from the remaining application documents. The features can be essential to the invention individually or in any combination with one another. The invention will then be explained in more detail below with the aid of a drawing. In the drawings:

Figure 1 shows a schematic structure of a

Headlight according to the invention according to a first embodiment;

Figure 2 shows a second embodiment of the inventive

headlight;

Figure 3 a first light distribution of a headlight

according to the invention on a measuring screen;

Figure 4a - d different light distributions according to the

Invention;

Figure 5 shows an embodiment of the invention;

Figure 6 shows a further embodiment of the invention and

Figure 7 shows a third embodiment of the invention;

Figure 8a + b Beam paths through a light-closing body according to the invention.

Figure 1 shows a headlight with a light source 10 and a reflector 12, which focuses the light emitted by the light source. The light source 10 is arranged in the first focal point of the reflector 12. In the second focal point of the reflector there is a light coupling surface of a glass fiber 14, which further splits into several arms 14a, 14b and 14c in the direction of light emission. The glass fiber 14 serves to transmit the light to another location. The ends of the glass fiber 14 or the glass fiber arms 14a to 14c are firmly connected to a transparent light closure body 16a to 16c. The transparent light-terminating body 16a to 16c, whereby a light-terminating body 16a to 16c is connected to a glass fiber arm 14a to 14c, is made of a plastic and is connected to the respective glass fiber arm 14a to 14c via an optical adhesive so that no light loss occurs at the transitions. In this way, an increase in efficiency of approx. 10% can be achieved. The light-terminating pieces 16a to 16b now each have a light-coupling surface, which is imaged by lenses 18a, 18b and 20. The lenses 18a and 18b are normal project module lenses that are rotationally symmetrical, light-collecting and plano-convex. The third arm 16b is connected to a flat lens 20. However, three

PES or aspherical lenses are used. Each of the lenses 18a, 18b, 20 is connected to an arm of the three-armed glass fiber 14a to 14c via one of the light-terminating bodies 16a to 16c.

The light-closing bodies 16a to 16c are all three differently shaped. To ensure that there is a homogeneous light distribution at the end of the closing bodies 16a to 16c and that no color or brightness spots occur, the length of the transparent light-closing bodies 16a to 16c is at least three times the diameter of the glass fiber. The glass fiber ends have a round or slightly elliptical cross-section in the case of the two PES lenses 18a, 18b and a rectangular cross-section in the area of the arm 14b. Other glass fiber cross-sections are conceivable.

The light closure bodies 16a to 16c have a rectangular cross-section with respect to the closure body 16b and a triangular cross-section with respect to the closure body 16a as well as an oval cross-section with respect to the closure body 16c. The rectangular cross-section creates a horizontal light/dark boundary in the light distribution from a measuring screen, the triangular cross-section a 15% increase and the elliptical cross-section a spot for a maximum. If the light closure bodies 16a to 16c are spaced and arranged accordingly from one another, the light distribution of a dipped beam for right-hand traffic can be realized by the three light closure bodies 16a to 16c.

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Figure 2 now shows an alternative design of the
Invention, whereby here, unlike in Figure 1, the light source
three LEDs are used 10a to 10c, each of which corresponds to a
Light closure bodies 16a to 16c are assigned. The
Light closure body 16a to 16c has a
Light coupling surface 22a to 22c into which the light from the
LEDs 10a to 10c are coupled directly. If LEDs are used as the light source, the connection of a fiber optic cable 14a to 14c is not necessary, since the
Thermal load of the light closure bodies 16a to 16c
by LEDs is so low that the use of expensive glass fibers 14 can be dispensed with.

Alternatively, several LEDs 16a to 16c can be positioned, whereby the LEDs 10a to 10c have a high luminous flux
The light-closing bodies 10a to 10c are in turn connected to lenses 18a, 18b and 20. The same applies to Figure 1 for the illustration and the cross sections.

The light end pieces 16a to 16c serve as
Cross-section converters that transport the light, whereby the
Lenses 18a, 18b serve as projection units that
Generally, the system should
Function of a low beam, but due to the flexibility it can also be a high beam and a fog light.

The advantages of the representation shown in Figure 2 are the use of white, highly efficient LEDs as the light source instead of glass fibers and gas discharge lamps, since LEDs are more efficient than gas discharge lamps and cheaper than a combination of gas discharge lamps and glass fiber. In addition, the complex reflector and the interposition of the glass fiber can be dispensed with and a smaller space requirement can be achieved.

Figure 3 now shows a light distribution on a measuring screen, as can be generated by the system according to Figure 1 and Figure 2. The representation is highly schematic. The cross sections of the glass fiber arms 14a to 14c are marked with 24 (not actually visible) and the cross sections of the light end pieces 16a to 16c, which are imaged by the system and the lenses 18a, 18b, 20, are marked with 26.

It can be seen from this that by arranging the three light end pieces with corresponding cross-sections, namely a triangular cross-section for the increase in light distribution as well as an oval cross-section for the maximum and a rectangular cross-section to create the horizontal light/dark boundary, a light distribution as required for a dipped beam in right-hand traffic can be provided in a simple and flexible manner.

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Figure 4 shows in representations a to c the flexibility of the light and a possible adaptive light distribution, which is easily made possible by the corresponding system.

For example, representation a shows the representation already shown in Figure 3, in which all three cross sections are connected to the light source. The representation shown in Figure a is a typical low beam representation. In addition, it can be provided that, for example, a cover as explained in Figure 5 can be used to ensure that only individual sections are connected to the light source. This makes it possible, for example, to achieve a light distribution as shown in representation b, namely, for example, a fog light setting in which only the rectangular cross section is connected to the light source.

In addition, it can be provided that the end bodies 16a to 16c and the lenses are connected to a stepper motor, whereby the end bodies 16a to 16c can be moved in three independent directions X, Y and Z, or horizontally, vertically and defocusing, so that the three light distributions can be shifted against each other and defocused. In this way, an adaptive light distribution can be achieved very easily. For example, illustration c shows a high beam setting, where the rectangular and triangular cross sections formed by the

Light closure bodies 16a and 16b are shifted relative to one another in such a way that the triangular cross-section is now centered above the rectangular cross-section. All three cross-sections are connected to the light source 10. The elliptical cross-section was shifted slightly upwards and to the left so that the maximum is at the HV point, namely the point on a measuring screen that corresponds to the intersection point between the horizontal and vertical center lines. In addition, the triangular cross-section can also be shifted upwards to the left, although only a shift to the left is shown here. For a smooth transition between light and dark, the elliptical and/or triangular cross-section can also be defocused, i.e. moved in the Z direction.

Finally, as shown in figure d, a cornering light function can be implemented by shifting the triangular and elliptical cross sections horizontally. This allows the 15° rise to be shifted or rotated to the left and right.

Adaptive light distribution can be implemented particularly easily and inexpensively due to the movement of the light-closing bodies 16a to 16c relative to one another. In addition, a control and/or regulating device can be provided which contains a program for controlling and/or regulating the individual light functions.

Figure 5 now shows the previously described design, wherein a diaphragm 28 is provided between the light-terminating body 16, which is firmly connected to the glass fiber 14 or the corresponding glass fiber arm, and the lens 18 (or 20), via which the light distribution emitted by the light-terminating body 16 can be switched on or off. The arrows 30 and 32 show the possible movements of the unit made up of glass fiber 14 and light-terminating body 16. The arrow 30 shows the movement of the unit made up of glass fiber 14 and light-terminating body 16, whereby the lens 18 and the diaphragm 28 can also be moved in the Z direction, i.e. defocusing. The arrow 32 shows the movement in the X direction, and the arrow 34 shows the movement in the Y direction. Here too, the lens 18 moves with the unit consisting of the light-terminating body 16 and the glass fiber 14. In this illustration, the numbering was chosen to be general, since it can be implemented for all three arms or for any number of arms.

Figure 6 now shows a further advantageous embodiment, according to which the connecting piece 16a to 16c is not firmly connected to the one glass fiber 14. Rather, the light termination pieces 16a to 16c are mounted on a turntable 36, wherein the lens 18 is arranged in such a way that it lies in the light emission direction of the glass fiber 14 (here arrow 38), so that light guided through the glass fiber 14, which passes through one of the light termination pieces 16a to 16c, namely

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whatever interacts with the glass fiber 14 and is passed through it can be imaged by the lens.

The right-hand illustration shows a corresponding turntable 36 from the front, while the left-hand illustration shows a side view of the system. The lens 18 is located in front of only one of the various light-closing bodies 16a, which interacts with the glass fiber 14 to transport light, with the glass fiber 14 coupling the light transported through it at the light coupling surface 22a and coupling it out at the light coupling surface 23a. Further cross sections are marked here with 16b, 16c and 16d. Here too, the arrows 30, 32 and 34 show a movement of the turntable in the X, Y and Z directions, i.e. vertically, horizontally and defocusing.

An alternative embodiment is shown in Figure 7, which shows a side view on the left and a front view on the right. The light-closing bodies 16 are arranged on a slide 38, whereby only one light-closing body 16 interacts with the glass fiber 14 and the lens 18 for light transmission and imaging by means of the translatory movement of the slide 38. Here, too, a shift in the defocusing direction indicated by the arrow 30 and vertically and horizontally indicated by the arrows 32 and 34 of the entire

Slide unit 39 with the light-closing bodies 16a to 16d defined therein.

The lens always remains assigned to the light emission direction 38 of the glass fiber 14.

The last figure, Figure 8, now shows a particularly advantageous and independently inventive embodiment of the invention, wherein the light-closing body 16 is given a special shape.

In order to create a light/dark boundary, the light guide end bodies have specific cross-sections. Normally, the cross-section is imaged equally brightly over the entire end surface due to its very simple shape and when projected through the lens, the complete outline of the light end body 16 therefore appears as a sharp light/dark boundary.

However, this sharp light/dark boundary is not only visible in places where it is desired, but along the entire contour. Such a sharp light/dark boundary can lead to obstruction of vision and disruption of the driver of a motor vehicle. Therefore, according to the invention, a new cross-section of the closure body is provided, which towards its end, i.e. towards the light coupling surface 23 of the light closure body, in the area of the light closure body 16 that does not have the light/dark boundary with

the 15% increase, is thickened, with this area marked here with 40. In this thickened area, as shown in Figure 8b, only rays with a large angle of incidence (or initial angles) can reach, which are marked here with 42. Rays with a small initial angle (marked here with 44) do not reach this area.

From Figure 8, illustration a, it can be seen that in the area in which the 15° light/dark boundary is created, both rays with large and small angles of incidence can reach. Here, too, the rays are marked 42 and 44. This makes it possible to achieve a brightness gradient, which is also projected further by the lens. In this way, a blurring of the light/dark boundary can be achieved in the area that is not used to create the 15° rise.

In the area marked b in Figure 8, representation b, rays can therefore arrive that have both a large and a small initial angle (rays 44 and 42). However, in the area marked a in representation b of Figure 8, only rays with a large initial angle, which are marked 42, can reach. This results in a different scattering of the light distribution and a weakening of the light distribution towards the edge.

Claims (18)

1. Headlight, comprising at least one light source ( 10 ), characterized in that the at least one light source ( 10 ) is assigned at least two transparent light-closing bodies ( 16 ), which have a light coupling surface ( 22 ) for the light of the at least one light source ( 10 ) and a light coupling surface ( 23 ), and at least one lens ( 18 , 20 ) which interacts with the light coupling surface ( 23 ) of the light-closing body ( 16 ) and is arranged after the light-closing body ( 16 ) in the light emission direction ( 38 ) and images the light coupled out by the light-closing body ( 16 ), characterized in that different light distributions can be achieved via the selection of at least one light-closing body ( 16 ), the cross section of the at least one selected light-closing body ( 16 ) and the number and the orientation of the selected light-closing bodies ( 16 ) relative to one another. 2. Headlight according to claim 1, wherein in particular three or more light-closing bodies ( 16 ) are provided. 3. Headlight according to claim 1 or 2, characterized in that LEDs ( 10 a to 10 c) serve as at least one light source ( 10 ). 4. Headlight according to one of claims 1 to 3, characterized in that a gas discharge lamp ( 10 ) or a halogen lamp serves as at least one light source ( 10 ). 5. Headlight according to one of the preceding claims, characterized in that the at least one light source ( 10 ) couples light directly into the at least one light coupling surface ( 22 ) of the light closure body ( 16 ). 6. Headlight according to one of the preceding claims, characterized in that a glass fiber ( 14 ) or a filter, in particular an infrared filter, is arranged between the at least one light source ( 10 ) and the light-terminating body ( 16 ). 7. Headlight according to one of the preceding claims, characterized in that the at least one light source ( 10 ) is assigned a reflector ( 12 ) and the light coupling surface ( 22 ) of the light closure body ( 16 ) and/or the upstream glass fiber ( 14 ) lies in the second focal point of the reflector ( 12 ). 8. Headlight according to one of the preceding claims, characterized in that the light-closing bodies ( 16 ) have a rectangular, triangular or round or oval cross-section or a cross-section composed of these basic shapes to produce a corresponding light distribution. 9. Headlight according to one of the preceding claims, characterized in that the glass fibers ( 14 ) have a round, rectangular or oval cross-section. 10. Headlight according to one of the preceding claims, characterized in that the lenses ( 18 a, b) are designed as PES lenses or as flat lenses ( 20 ). 11. Headlight according to one of the preceding claims, characterized in that the light-closing bodies ( 16 ) and/or the lenses ( 20 , 18 ) are movable relative to one another in the X, Y, Z direction, in particular vertically, horizontally or defocusing, to produce an adaptive light distribution. 12. Headlight according to one of the preceding claims, characterized in that a beam diaphragm ( 28 ) is provided between the light-terminating body ( 16 ) and the lens ( 18 , 20 ) for switching the individual light distributions on and off. 13. Headlight according to one of the preceding claims, characterized in that the light-closing bodies ( 16 ) are arranged on a rotationally movable turntable ( 36 ) and/or a translationally movable slide ( 39 ), wherein various connection pieces ( 16 ) can be coupled to the at least one light source ( 10 ) by the movement of the turntable ( 36 ) and/or the slide ( 39 ). 14. Headlight according to one of the preceding claims, characterized in that the light-closing bodies ( 16 ) consist of plastic, in particular PC or PMMA, or of glass. 15. Headlight according to one of the preceding claims, characterized in that the light-terminating bodies ( 16 ) are at least three times as long in the direction of the optical axis as the cross-section of a glass fiber ( 14 ) arranged between the light source ( 10 ) and the light-terminating body ( 16 ). 16. Headlight according to one of the preceding claims, characterized in that the light-closing body ( 16 ) has a thickening ( 40 ) at its end pointing in the direction of the light-coupling surface ( 23 ), into which only rays ( 42 ) with large initial angles reach and thereby a brightness distribution is achieved which leads to a blurred light/dark boundary. 17. Headlight according to one of the preceding claims, characterized in that the thickening ( 40 ) increases linearly in the direction of the light coupling surface ( 23 ). 18. Headlight according to one of the preceding claims, characterized in that the thickening ( 40 ) is provided only in the region of the light-terminating body(s) ( 16 ) which do not produce the 15° rise and/or the horizontal edge of the light/dark boundary.