Patent Application
20250075871
The invention relates to an illumination device for a motor vehicle headlight, which illumination device comprises the following:
The invention further relates to a motor vehicle headlight having at least one illumination device according to the invention.
This area of light distribution above the cut-off line is also called the overhead or sign light area (derived from the visibility of traffic signs).
The legal measurement points in this area range up to 4° above the horizon and are characterized by minimum and maximum values as well as so-called sum values for the illumination intensity occurring in each of the measurement points.
Projection systems with dipped beam function have very little light above the cut-off line due to the system as this overhead area is effectively shadowed by the bulb shield used in projection systems.
Due to the effective shadowing, special measures are required to adequately illuminate these measurement points with suitable amounts of light. At the same time, care must be taken to ensure compliance with specified maximum values in the vicinity of the cut-off line. These maximum values are also known as “glare values”.
The optical device is generally a modification of the “original” lens entry or light emitting surface of the projection lens, wherein a wide variety of modifications are generally possible for directing light to an area above the cut-off line.
A fundamental problem associated with all known solutions having such optical devices is that the directed beams are concentrated in a relatively small area such that, on the one hand, too much light reaches this area and, on the other hand, other areas have light values that are too low, i.e. that this area is not uniformly illuminated by the known solutions.
It is an object of the invention to provide an improved illumination device.
This object is achieved by virtue of the fact that the projection lens comprises an optical device arranged on the projection lens, which comprises a plurality of free-form lenses each having an active surface, wherein the optical device is designed to direct part of the light entering the projection lens and exiting via the active surfaces of the free-form lenses to a region above the asymmetrical cut-off line of the dipped beam distribution.
The targeted selection of the active surfaces and their course on the projection lens enables the widest possible and most uniformly illuminated sign light in the dipped beam distribution.
It can be provided that the optical device is arranged on the light emitting surface of the projection lens and forms a manipulated part of the light emitting surface deviating from the convex light emitting surface.
It can be provided that the active surface of a respective free-form lens and the light emitting surface form a starting edge in a common surface section line, wherein the active surface, starting from the starting edge, extends away from the light emitting surface along two side edges up to a slope edge opposite the starting edge, preferably in the direction of the main emission direction, which slope edge has a first end and a second end, wherein the first end has a first distance to the light emitting surface along a surface normal in an orthogonal projection onto the light emitting surface, and wherein the second end has a second distance to the light emitting surface along a surface normal in an orthogonal projection onto the light emitting surface.
It can be provided that the free-form lenses of the optical device are arranged next to each other in a horizontal row in the installation position of the illumination device in a motor vehicle headlight, wherein the first distance of the active surfaces, starting from a first free-form lens of the horizontally arranged free-form lenses, in the course up to a last free-form lens is initially smaller than the second distance, wherein the first distance increases in the course to the optical axis and the second distance decreases such that the first distance of the free-form lenses in the region of the optical axis is the same as the second distance, wherein the first distance continues to increase in the course away from the optical axis and the second distance continues to decrease.
It can be provided that the optical device is arranged on the light entry surface of the projection lens and forms a manipulated part of the light entry surface deviating from the light entry surface.
It can be provided that the free-form lenses are arranged next to each other in several parallel rows.
It can be provided that the active surface of a respective free-form lens and the light entry surface form a starting edge in a common surface section line, wherein the active surface, starting from the starting edge, extends away from the light entry surface along two side edges up to a slope edge opposite the starting edge, which slope edge has a first end and a second end, wherein the first end has a first distance to the light entry surface along a surface normal in an orthogonal projection onto the light entry surface, and wherein the second end has a second distance to the light entry surface along a surface normal in an orthogonal projection onto the light entry surface.
It can be provided that the first and second distance of an active surface are the same size, wherein the first and second distance of every active surface are preferably the same size.
It can be provided that the free-form lenses of the optical device are arranged with respect to each other in such a way that a logo, for example a manufacturer's logo, is formed.
It can be provided that the free-form lenses are arranged directly next to each other in a line.
It can be provided that the active surfaces are curved.
It can be provided that the cut-off line is asymmetrical or straight.
This object is also achieved by a motor vehicle headlight having at least one illumination device according to the invention.
The invention is explained below in more detail based on exemplary drawings. In the drawings,
Furthermore, the illumination device 10 comprises a bulb shield 20 having an optically relevant shield edge for producing an asymmetrical cut-off line, wherein the light module 11 is arranged on an upper side of the bulb shield 20 in the installed position of the illumination device 10 in a motor vehicle headlight and cooperates in combination with the optically relevant shield edge of the bulb shield 20 to produce dipped beam distribution.
Furthermore, the illumination device comprises a projection lens 100 with an optical axis B, which projection lens 100 is designed to image the light that can be produced by the light module in front of the illumination device 10 in a main emission direction, wherein the projection lens 100 has a light entry surface 110 and a convex light emitting surface 120 opposite the light entry surface 110.
On the projection lens 100, an optical device 200 is arranged on the light emitting surface 120, wherein the optical device 200 forms a manipulated part of the light emitting surface deviating from the convex light emitting surface 120, which comprises a plurality of free-form lenses 210 each having an active surface 211, as seen in
In the exemplary embodiment shown in
In the exemplary embodiment shown in
In the exemplary embodiment shown in
In the example shown in the figures, the free-form lenses 210 of the optical device 200 are arranged next to each other in a horizontal row in the installation position of the illumination device 10 in a motor vehicle headlight, wherein the first distance A1 of the active surfaces 211, starting from a first free-form lens of the horizontally arranged free-form lenses, in the course up to a last free-form lens is initially smaller than the second distance A2, wherein the first distance A1 increases in the course to the optical axis B and the second distance A2 decreases such that the first distance A1 of the free-form lenses in the region of the optical axis B is the same as the second distance A2, wherein the first distance A1 continues to increase in the further course away from the optical axis B and the second distance A2 continues to decrease, as sketched out in
Furthermore, it is also possible that the optical device 200 in another example is arranged on the light entry surface 110 of the projection lens 100, wherein the free-form lenses 210 are arranged next to each other in several parallel rows.
The active surface 211 of a respective free-form lens 210—similar to the example shown in the figures—and the light entry surface 110 form a starting edge in a common surface section line, wherein the active surface 211, starting from the starting edge 211a, extends away from the light entry surface 110 along two side edges up to a slope edge 211b opposite the starting edge 211a, which slope edge 211b has a first end and a second end, wherein the first end has a first distance A1 to the light entry surface 120 along a surface normal in an orthogonal projection onto the light entry surface 110, and wherein the second end 212b has a second distance A2 to the light emitting surface 120 along a surface normal in an orthogonal projection onto the light entry surface 120.
In this case, the first and second distance A1, A2 of an active surface 211 are the same size, wherein the first and second distance A1, A2 of every active surface 211 are preferably the same size.
It can, for example, be provided that the free-form lenses 210 of the optical device 200, in the case that the optical device is arranged on the light entry surface 110, are arranged with respect to each other in such a way that a logo, for example a manufacturer's logo, is formed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20198338.4 | Sep 2020 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/070886 | 7/26/2021 | WO |
