Patent Grant
11761603
This application is a § 371 application of International Application No. PCT/EP2020/071952, filed Aug. 5, 2020, which claims the benefit of EP Patent Application No. EP 19193120.3, filed Aug. 22, 2019, and International Application No. PCT/CN2019/099608, filed Aug. 7, 2019, which are incorporated by reference as if fully set forth.
The present invention relates to the field of automotive front-lighting, and particularly to a front-lighting system for a vehicle.
Bi-function Poly-Ellipsoidal System (PES) solution for a headlamp has been widely used in automotive lighting today. Generally speaking, an opaque shutter is utilized in this solution to enable switching between a high beam (also known as an upper beam) and a low beam (also known as a lower beam). In such an approach, due to a thickness of the opaque shutter itself, a dark area exists in the final projected beam pattern, especially between the high beam and the low beam.
In order to avoid the dark area as indicated above, it has been proposed to use a transparent shutter instead of an opaque one in an automotive lighting system, see e.g. WO2018192963A1 and CN205619152U. However, due to limitations in size of optical elements, such as of the transparent shutter itself, the light beam input from the light source, such as the low-beam light source and the high-beam light source, shall be narrow enough such that undesired refraction out of the transparent shutter is avoided for example at some edges thereof, for the purpose of reducing the loss of light and improving the quality of beam pattern. To this end, in a conventional front-lighting system for a vehicle, especially those equipped with a transparent shutter, a single low-beam light source and also a single high-beam light source, in particular both having small lateral sizes, are used. Although this helps to avoid the dark shadow caused by an opaque shutter between the low-beam pattern and the high-beam pattern, problems do exist due to limitations in the small size and further the low light intensity of light sources themselves. Those problems are extremely notable for the high-beam light pattern because it is normally required to provide a light intensity strong enough to give a bright and clear view for drivers.
The present invention provides a front-lighting system for a vehicle, so as to eliminate or at least alleviate one or more of the above mentioned disadvantages.
According to an embodiment of the present invention, a front-lighting system is proposed for a vehicle. The front-lighting system comprises a first light source, a second light source, a first primary optics, a second primary optics, a transparent shutter, and a secondary optics. Preferably, the first light source comprises a low-beam light source and the second light source comprises a high-beam light source, and vice versa. In this way, two separate light sources are used respectively for providing the high beam pattern and the low beam pattern.
Specifically, the first primary optics is designed to receive light from the first light source and project it onto the transparent shutter and the secondary optics. As an example, the first primary optics can be selected as a first reflector and/or comprise a reflective light in-coupling surface. Alternatively, a first collimator may also be used, and/or a refractive light in-coupling surface may be comprised in the first primary optics. In case that the first primary optics is designed to be a first collimator, not only a projection of light from the first light source onto the transparent shutter and the secondary optics can be achieved, but also a beam shaping of the same light will be obtained. Besides, the refractive light in-coupling surface of the first primary optics can be further configured for near field focusing other than collimation.
In a similar way, a second primary optics is also provided, which second primary optics is designed to receive light from the second light source and project it onto the transparent shutter. Again, the second primary optics can be chosen as a second reflector or a second collimator. Specifically, the second reflector is configured to reflect the light emitted by the second light source towards the transparent shutter. As for the second collimator, it is arranged for collimating the light emitted by the second light source towards the transparent shutter. In other words, the second reflector and collimator are used herein to perform preliminary processing on the light emitted from the second light source prior to entering the transparent shutter. Besides, the second collimator also helps to shape the light beam emitted from the second light source. In a particular embodiment, the second collimator can also be integrated with the transparent shutter, such as on its entrance side facing the second light source. As similar to the first primary optics, the second primary optics may also comprise a light in-coupling surface, especially, a reflective or refractive light in-coupling surface. In this case, not only a projection of light from the second light source can be obtained, but also collimation or near field focusing of the same light will be achieved.
Additionally, the transparent shutter is designed to receive light from the first light source via the first primary optics and prevent a lower part of it from entering the secondary optics. In this case, the lower part of light coming out of the first light source will not form any image through the secondary optics, and only the upper part thereof goes into the secondary optics. This helps to form a low beam pattern with a clear cut-off line for example, if the first light source is chosen as a low-beam light source. In such a way, the dark area between the two beam patterns, such as between the high beam pattern and the low beam pattern, caused by any traditional opaque shutter can also be avoided. Further, with regard to the second beam portion emitted from the second light source, the transparent shutter is designed to receive it via the second primary optics and then project it onto the secondary optics. In combination with the secondary optics, a second beam pattern, such as a high beam pattern if the second light source is selected to be a high-beam light source, can be projected onto a road.
Specifically, in an optional embodiment, the secondary optics is designed to receive light from both the first primary optics and the transparent shutter, and project it onto the road in front of the vehicle. As an optional instance of the above embodiment, a projection lens can be used as the secondary optics.
Furthermore, in an embodiment of the above proposed front-lighting system, the transparent shutter also comprises an air-exposed slit, which air-exposed slit is carved within the transparent shutter and configured further to redirect the light received by the transparent shutter from the second light source towards a middle axis of the transparent shutter. According to an example instance of the above embodiment, the transparent shutter can be shaped to have a cylinder portion where the air-exposed slit is located, and the middle axis will be a symmetric axis of the cylinder portion. By providing the air-exposed slit with such a configuration that light received by the transparent shutter from the second light source is redirected towards the middle axis of the transparent shutter, the part of light beam incident onto the transparent shutter from the second light source is allowed to be concentrated more towards a middle portion of the transparent shutter as compared with that towards outer sides of the transparent shutter. This helps at least to reduce a larger input light beam, such as from the second light source, into a smaller one, thus contributing to a decreased loss of light for example due to a reduced outward refraction at outer sides of the transparent shutter.
In an optional embodiment of the present invention, the transparent shutter comprises different optical surfaces, such as a light out-coupling surface at which light is out-coupled from the transparent shutter towards the secondary optics. The light out-coupling surface is for example designed to be flat or in a free form, thus allowing change in the out-coupling angle and/or distribution of output light. Preferably, in an example instance of the above mentioned embodiment according to the present invention, the air-exposed slit is further designed to redirect the light received by the transparent shutter from the second light source into a concentrated light spot on the light out-coupling surface of the transparent shutter. In this case, light coming out of the second light source and being incident into the transparent shutter is not only redirected more towards a middle section of the transparent shutter, but also concentrated into a light spot, especially a narrowed one, onto the light out-coupling surface of the transparent shutter. Further preferably, the concentrated light spot as redirected by the air-exposed slit onto the light out-coupling surface of the transparent shutter also comprises such a distribution that light intensity is largest at the center of the light spot and decreases gradually towards outer edges thereof. In this way, a light spot with the desired distribution of light intensity can be output, such as for a high beam part of the final beam pattern projected onto the road, if a high-beam light source is used as the second light source.
Schematically, according to an optional embodiment of the present invention, in the above proposed front-lighting system for a vehicle, the air-exposed slit of the transparent shutter extends perpendicularly to a propagation direction of light from the second light source within the transparent shutter. A perpendicular extension of the air-exposed slit within the transparent shutter allows an efficient and optionally symmetric redirection of light input from the second light source towards a middle section of the transparent shutter, leading to a minimum loss of light caused by such a redirection. According to an example embodiment of the present invention, the transparent shutter is shaped to have a cylinder portion where the air-exposed slit is located, and the propagation direction of light from the second light source is roughly going down along the symmetry axis of the cylinder portion. In this case, within the transparent shutter, the extension direction of the air-exposed slit will be orthogonal to the symmetry axis of the cylinder portion.
In the above proposed front-lighting system for a vehicle, not only a transparent shutter is used, but also an air-exposed slit is carved therein for at least redirecting light input from the second light source, such that no shading of light transmission is caused by the shutter on the one hand, and on the other hand, the part of light input from the second light source is concentrated in size and optionally provided with a desired distribution of light intensity. In this case, usage is allowed of a larger sized, second light source, or possibly of multiple second light sources configured for example in an array, thus enabling potential acquisition of a desired high beam pattern with the required light intensity and overall amount of light output from the front-lighting system if a high-beam light source is used as the second light source.
According to an optional embodiment of the present invention, in the above proposed front-lighting system for a vehicle, the second light source comprises a plurality of sub-light sources arranged for example in an array of (2m+1) rows and (2n+3) columns, where m and n are both integers equal to or greater than 0. In the above embodiment, further optionally, the air-exposed slit comprises one or more sub-slits, each sub-slit extending in parallel to a respective row of the sub-light sources. As can be seen, in the proposed front-lighting system, multiple individuals in one or more rows are used for the second light source, and accordingly, one or more sub-slits are provided, where each sub-slit is associated with one respective row of the sub-light sources. For example, if the transparent shutter is disposed above the array of sub-light sources of the second light source, where light from the second light source runs from the bottom to up through the transparent shutter, each sub-slit will extend horizontally above the respective row of sub-light sources.
Furthermore, in an example instance of the above described embodiment, each sub-slit also comprises two side parts, wherein each part is located on either side of a middle part of the transparent shutter, which middle part is exempted from the air-exposed slit, i.e., from the one or more sub-slits. In other words, in the front-lighting system as proposed by the present invention, the transparent shutter comprises a middle part (also called a middle section hereinafter), for example a cylinder part around its middle axis, and each sub-slit consists of two independent side parts, each side part being located at either side of the middle part of the transparent shutter. This means that each sub-slit is not cutting through the transparent shutter, at least with no perforation at the middle part of the transparent shutter. This helps to maintain the transparent shutter in a one-piece construction, and also makes it easier for manufacturing or machining the transparent shutter.
According to an example instance of the above embodiment, in the transparent shutter of the front-lighting system, each sub-slit further comprises a first surface and a second surface opposite to each other. To be specific, as compared with the second surface, the first surface of each sub-slit is positioned closer to a light entrance surface of the transparent shutter, where light from the second light source is incident thereon. As an example, if the transparent shutter is positioned above the second light source, and light from the second light source is propagating from the bottom to up within the transparent shutter, the first and second surfaces of each sub-slit will be the lower and upper surfaces respectively. Furthermore, both of the first surface and the second surface comprise at least portions located at the two side parts of each sub-slit, which portions are shaped such that light incident thereon is redirected to be inclined towards the middle part of the transparent shutter, especially relating to a middle-positioned sub-slit. It should be indicated that in the above expression, the term of “middle-positioned sub-slit” refers to that having an equal number of sub-slits at either side thereof. In other words, if an odd number of rows are provided of sub-slits, the middle-positioned sub-slit shall be the one sandwiched in the middle, thus, for example, meaning the second one if the total row number counts to three, the third one if the total row number counts to five, and so on. Besides, according to an optional embodiment of the present invention, each sub-slit of the transparent shutter also comprises a medial surface, which medial surface is perpendicular to the propagation direction of light received from the second light source within the transparent shutter. Again, for example, if the transparent shutter is positioned above the second light source, and light from the second light source is propagating from the bottom to up within the transparent shutter, the sub-slit extends horizontally within the transparent shutter and the medial surface thereof can be a horizontal plane cutting through the sub-slit at the middle. Further preferably, in the above embodiment of the present invention, the first surface and the second surface of each sub-slit are configured as mirror symmetrical to each other with respect to the medial surface of the respective sub-slit, making it easier for carving sub-slits within the transparent shutter and providing an accurate control over the redirection of light coming out from the second light source.
According to an optional embodiment of the present invention, in the above proposed front-lighting system for a vehicle, the plurality of sub-light sources are arranged especially in an array of 1 row and (2n+3) columns, where n is an integer equal to or greater than 0, meaning that only one row of sub-light sources is comprised in the second light source. In this case, the air-exposed slit comprises accordingly one single sub-slit. In an example instance of the above embodiment, for the single sub-slit of the transparent shutter, the first surface comprises two side sections, which are located respectively on either side of the middle part of the transparent shutter. Optionally, each side section of the first surface of the single sub-slit is curved, especially being convex towards the second light source. Alternatively, each side section of the first surface of the single sub-slit comprises a sloped surface, wherein a portion of the sloped surface adjoining the middle part of the transparent shutter is spaced farthest from the second light source as compared with remaining portions thereof. Further alternatively, each side section of the first surface of the single sub-slit comprises a stepped surface with one or more steps. According to one example instance, each step comprises a curved surface being convex towards the second light source. According to another example instance, each step comprises two facets—a first facet and a second facet. The first facet is configured to be perpendicular to the medial surface of the single sub-slit. The second facet is sloped and has a portion thereof closest to the middle part of the transparent shutter, wherein such a closest portion of the second facet is spaced farthest from the second light source as compared with remaining portions thereof. In a similar way, the second surface of the single sub-slit also comprises two side sections, with each located on either side of the middle part of the transparent shutter. Especially, for the single sub-slit, the second surface is mirror symmetric to the first surface with respect to its medial surface. Thus, specific constructions for the second surface can be obtained easily for a skilled person in the art based on the above detailed structures of the first surface, thus not being repeated herein for simplicity.
According to yet another embodiment of the above front-lighting system, the transparent shutter is further designed to project the light received from the second light source via the second primary optics onto the secondary optics through total internal reflection. A total internal reflection in the transparent shutter helps to fold the light path, so as to keep the first light source and the second light source, such as the low-beam light source and the high-beam light source, away from each other within the whole system. For example, the high-beam light source and the low-beam light source can be located at a distance larger than 20 mm in the assembled system. In this way, the heat dissipation can be improved, and the color non-uniformity of the final beam pattern can also be lowered. As a further preferable instance, the total internal reflection can occur one or more times within the transparent shutter, which facilitates a further reduction in size of the front-lighting system. In this way, the horizontal and/or vertical dimensions of the front-lighting system can be shortened, and the whole system becomes more compact.
In an exemplary embodiment of the above front-lighting system, the first light source is placed in a first focal plane of the first primary optics, and the second light source is placed in a first focal plane of the second primary optics. Besides, the transparent shutter is placed in one or more of: a second focal plane of the first primary optics, a second focal plane of the second primary optics, and a focal plane of the secondary optics, especially in all these three focal planes at the same time. Preferably, the transparent shutter is placed in the focal points of these focal planes. Apparently, those skilled in the art, having benefited from teachings of the present invention, can conceive a further positioning for various components, such as the first primary optics, the second primary optics, the secondary optics, the transparent shutter, and the two light sources, in the front-lighting system. The present invention should not be limited to those dispositions in respective focal planes or focal points.
According to an optional embodiment of the present invention, in the above proposed front-lighting system for a vehicle, the transparent shutter is made of polymethyl methacrylate (PMMA) or polycarbonate (PC). However, it should be noted that based on the teaching of the present invention, those skilled in the art will easily obtain other suitable materials and also suitable manufacturing or processing processes for the transparent shutter and the air-exposed slit carved therein. The present invention should not be limited in this regard. According to an exemplary implementation, the transparent shutter in the above proposed front-lighting system can be manufactured by injection molding as a one-piece plastic component, and the air-exposed slit can be carved therein for example by laser means. Obviously, this is just disclosed as an example and the present invention is not restricted only to it.
It will be appreciated by those skilled in the art that two or more of the above disclosed embodiments, implementations and/or aspects of the present invention may be combined in any way deemed useful. Different modifications and variations of the front-lighting system for a vehicle can be carried out by a person skilled in the art based on the disclosure of the present disclosure.
These and other aspects of the present invention will be described now in more detail, with reference to the appended drawings showing embodiments and forming a part of the present invention. Specifically, in the drawings:
While the present invention is susceptible of embodiments in many different forms, there is shown in the drawings and will be described in detail herein only one or more specific embodiments, with the understanding that the present description is to be considered as exemplary of the basic principle of the present invention and not intended to limit the present invention only to the specific embodiments shown and described herein.
It should be noted that various components in different figures are not drawn to scale. Besides, relative positions between individual elements shown in the figures are only used to illustrate the basic principle of the present invention and should not be considered to limit the scope of the present invention.
With reference to
In the specific embodiment as shown by
Further, discussions with relevance to the other beam portion, i.e., the one emitted by the second light source BS2, are provided in the following. With continued reference to
With a transparent shutter 14 incorporated into a front-lighting system 1 for a vehicle, the traditional opaque shutter is replaced and no dark area will be observed in the final projected beam pattern, especially between the high beam pattern and the low beam pattern. This is definitely distinguished from the beam pattern obtained by an existing headlamp with an opaque shutter equipped. In other words, in the front-lighting system 1 for a vehicle as proposed by the present invention, a clear cut-off line is formed in the projected low beam pattern without any shading.
Besides, as also shown in
With continued reference to
With further reference to
With reference to
With continued reference to
According to an optional embodiment as for example shown by
Apart from the single-maximum characteristic, as also evident from a comparison between
With reference to
However, the difference from
Turning to the enlarged view of
It should be noted that although in the figures, the total internal reflection of light coming from the second light source is shown to occur only once, this should not be interpreted as limiting the present invention. As a matter of fact, a skilled person in the art, having benefited from the teaching of the present invention, will easily conceive other suitable constructions of the transparent shutter such that the total internal reflection of light coming from the second light source occurs more than once within the transparent shutter. By means of multiple times of total internal reflection, the second, such as high-beam, light source may be installed at the same side as the first, such as low-beam, light source. That is to say, a vertical distance between the two light sources can be greatly reduced, and the large spacing is mainly achieved through a horizontal distance between them. In this way, a vertical space of the front-lighting system will be shortened significantly, and thus the whole system becomes very compact at least in vertical direction. Besides, with multiple times of total internal reflection, the light path within the front-lighting system can be folded such that the first, such as low-beam, light source will keep away from the second, such as high-beam, light source in space based on practical implementations. This helps to offer design flexibility, outstanding heat dissipation feasibility and less color non-uniformity.
It is also important to note that light rays shown in the figures, only represent part, but not all, of the light rays within the whole optical system. In fact, the light rays shown in all the figures are only used as representative examples for the purpose of illustrating the basic principle of the present invention, and clearly should not be read as exhaustive examples of all the light rays within the entire system.
With regard to the materials and manufacturing or processing processes suitable for the transparent shutter, different options can be used. For example, in an embodiment, the transparent shutter can be fabricated by injection molding as a one-piece component, such as by polymethyl methacrylate (PMMA), polycarbonate (PC), or other plastic materials. Apparently, materials other than plastic, and processes other than injection molding can also be utilized based on specific situations, and the present invention should not be limited in this aspect.
In should be noted as well that although the transparent shutter is shown in sectional views in all the figures of the present invention and seems to have a flat contour, the actual 3D shape of the transparent shutter, especially having the air-exposed slit introduced therein, might be rather complicated. In some embodiments, the transparent shutter can be designed to have a flat contour. Alternatively, in other embodiments, the transparent shutter can be designed as a curved body, maybe of a free-form contour. Specific illustrations about different contours of the shutter, both in the drawings and the specification, should not be interpreted to be limiting, but rather are to be considered as exemplary disclosures.
It should also be noted that the above-mentioned embodiments illustrate rather than limit the present invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope and spirit of the present invention. Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific forms as set forth herein. Rather, the scope of the present invention is limited only by the accompanying claims. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention.
Furthermore, although individual features may be included in different claims, these may possibly be advantageously combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claims. Use of the verb “comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. Also, references to first, second etc. are merely to be considered as labels and do not imply or describe any ordering, sequence, relation or properties of the features prefixed by these terms. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/CN2019/099608 | Aug 2019 | WO | international |
| 19193120 | Aug 2019 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/071952 | 8/5/2020 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2021/023755 | 2/11/2021 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20140321141 | Bauer et al. | Oct 2014 | A1 |
| Number | Date | Country |
|---|---|---|
| 205 619 152 | Oct 2016 | CN |
| 3 473 917 | Apr 2019 | EP |
| 2013075157 | May 2013 | WO |
| 2018192963 | Oct 2018 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20220282846 A1 | Sep 2022 | US |
