EP3961085A1

EP3961085A1 - Lighting system for automotive headlamp

Info

Publication number: EP3961085A1
Application number: EP20192564.1A
Authority: EP
Inventors: designation of the inventor has not yet been filed The
Original assignee: Lumileds LLC
Current assignee: Lumileds LLC
Priority date: 2020-08-25
Filing date: 2020-08-25
Publication date: 2022-03-02

Abstract

An automotive lighting system (1) for a vehicle comprising a light source (11), a first lens (12) having a light entrance surface (121), and a second lens (13), a first protrusion (141) being provided at a periphery of the light entrance surface (121) of the first lens (12) with respect to an optical axis (L) of the automotive lighting system (1). Alternatively, the automotive lighting system (1) comprises a light source (11) having a first sub light source (111) and a second sub light source (112), a first lens (12) having a light entrance surface (121), and a second lens (13), wherein a first protrusion (141) and a second protrusion (142) are provided on the light entrance surface (121) of the first lens (12) with a first light exit face (1412) of the first protrusion (141) and a second light exit face (1422) of the second protrusion (142) keeping in contact with the light entrance surface (121) of the first lens (12). Besides, a partial overlapping (1400) exists between the first light exit face (1412) of the first protrusion (141) and the second light exit face (1422) of the second protrusion (142), such that the second lens (13) projects light from the first and second sub light sources (111, 112) on a road in front of the vehicle as a light pattern with a first maximum light intensity I_max1, a second maximum light intensity I_max2, and a minimum light intensity I_min between the first maximum light intensity I_max1 and the second maximum light intensity I_max2, where I_min/I_max1 > 90% and I_min/I_max2 > 90%.

Description

FIELD OF THE INVENTION

The present invention relates in general to the field of automotive front-lighting, and in particular to an automotive lighting system for a vehicle.

BACKGROUND OF THE INVENTION

Light Emitting Diodes (LEDs) are rapidly gaining popularity because of their longevity and low energy credentials. Advances in manufacturing have led to the emergence of chip-sized LED packages or modules in which a plurality of LEDs is packaged together, like a matrix comprising one or more rows of LEDs.
Such LED packages or modules typically produce a Lambertian luminous distribution centered about an optical axis of the package or module. In many headlamps and other lighting devices comprising such LED packages or modules, a lens is used to image a light distribution or a light pattern generated by the light source (for example a LED matrix) into the far field. In this case, due to a curvature in the light entrance surface of the lens, LEDs or pixels of the light source located at a periphery of the lens are typically spaced apart by a larger distance from the respective in-coupling portions of the light entrance surface of the lens, as compared with those LEDs or pixels of the light source located at a center of the lens. This results in a very large loss of light or an extremely low efficiency of light in-coupling at least at the edges of the lens.
Besides, in many headlamps and other lighting devices comprising the above mentioned LED packages or modules, any inhomogeneity or intensity structure produced by the light source will be projected and reproduced in the far field. Especially, in matrix systems, a problem will arise where gaps between the individual LEDs or pixels of the light source are imaged as black lines in the far field.
Accordingly, there is a need for an automotive lighting system for use in a vehicle which is distinguished by an improved performance, where performance is assessed at least on the illumination homogeneity and the efficiency of light in-coupling.

SUMMARY OF THE INVENTION

The present invention provides an automotive lighting system for use in a vehicle, so as to eliminate or at least alleviate one or more of the above mentioned shortcomings or disadvantages.
According to a first aspect of the present invention, in an embodiment, an automotive lighting system is proposed for use in a vehicle. The automotive lighting system comprises a light source, a first lens and a second lens. In the above automotive lighting system, the light source comprises a first sub light source, and the first lens comprises a light entrance surface and a light exit surface. From the perspective of propagation, light is firstly emitted out from the light source, for example from the first sub light source, then incident onto the first lens (for example onto the light entrance surface thereof), and refracted out thereby towards the second lens. After that, the second lens receives light refracted out from the first lens and helps to project it towards a road in front of the vehicle, thus providing lighting in front of the vehicle. Besides, in the above proposed automotive lighting system, the light entrance surface of the first lens is provided with a first protrusion to receive light from the first sub light source. This means that, in the above proposed automotive lighting system, light emitted from the first sub light source of the light source will not be incident into the first lens until they pass through the first protrusion provided ahead on the light entrance surface of the first lens. Specifically, the first protrusion is located at a periphery of the light entrance surface of the first lens with respect to an optical axis of the automotive lighting system. For example, if the first lens is shaped to have a circular contour and the optical axis passes through the first lens at the circle's center, the first protrusion can be disposed at the circumference of such a circular first lens.
In the above automotive lighting system proposed by the present invention for use in a vehicle, a first protrusion is introduced at a periphery of the light entrance surface of the first lens. In this case, after emission out from the light source (especially the first sub light source), light will be incident firstly at the first protrusion provided on the light entrance surface of the first lens, pass therethrough such as by total internal reflections, and then enters the first lens. This constitutes a clear difference from an automotive lighting system without any protrusion, where the light source is farer away from the light entrance surface of the lens at the edges of the lens as compared with that at the center of the lens, at least due to a curvature in the light entrance surface of the lens, thus leading to a poor light in-coupling from the light source into the first lens at its edges. That is to say, in the above automotive lighting system for a vehicle proposed by present invention, at least an extra first protrusion is introduced at an edge of the light entrance surface of the first lens, helping to in-couple light from the light source firstly into the first protrusion, and then into the first lens at an optically downstream position. In the end, more light coming out of the light source can be in-coupled into the first lens because of the extra light in-coupling element - the first protrusion, which is positioned ahead of the first lens so as to reduce the bigger distance existing otherwise between the light source and the first lens at an edge of the light entrance surface of the first lens if no protrusion is provided, thus leading to an increased efficiency of light in-coupling.
Optionally, according to an embodiment of the present invention, in the above proposed automotive lighting system for a vehicle, the first sub light source is located at an off-axis position with respect to the optical axis of the automotive lighting system, as similar to the first protrusion. This is beneficial for allowing a higher percentage of light from the first sub light source entering the first protrusion, again helping to increase the efficiency of light in-coupling furthermore.
Optionally, according to an embodiment of the present invention, in the above proposed automotive lighting system for a vehicle, the light source comprises a plurality of second sub light sources, which are distributed in an array along with the first sub light source. In this case, the light entrance surface of the first lens is provided correspondingly with a plurality of second protrusions, which are distributed in an array along with the first protrusion across the light entrance surface of the first lens, where each of the plurality of second protrusions is configured to receive light from a respective one of the plurality of second sub light sources.
By providing an array distribution of multiple sub light sources (including the first and second sub light sources) and the respective protrusions (including the first and second protrusions), a matrix light pattern (such as a matrix high beam light pattern, where the light source acts to emit a high beam) can be provided by the proposed automotive lighting system of the present invention, where each pair of sub light source and its respective protrusion acts as a matrix pixel. This at least enables such a possibility that the final light pattern as projected in front of the vehicle by the second lens is provided with a desired form or shape, for example by turning on only a few pairs of sub light source and protrusion, but leaving the rest of them turned off.
Optionally, according to an embodiment of the present invention, in the above proposed automotive lighting system for a vehicle, the first protrusion comprises a first light entrance face and a first light exit face opposite thereto, wherein the first light exit face of the first protrusion is in contact with the light entrance surface of the first lens. That is to say, the first light exit face of the first protrusion is a contact interface between the first protrusion and the first lens, where light is coming out from the upstream first protrusion and enters the downstream first lens. In other words, the first protrusion is contiguous to the first lens at the first light exit face thereof, meaning that the first light exit face of the first protrusion is invisible in an external view of the automotive lighting system as assembled. This renders the first light exit face of the first protrusion to be virtual in a sense. Preferably, according to the above mentioned embodiment of the present invention, in the automotive lighting system for a vehicle, the first light exit face of the first protrusion is 1 to 4 times larger than the first light entrance face of the first protrusion. This helps to reduce the possibility that light is refracted out from the first lens after passing through the first protrusion. Thus, more light will be totally internal reflected into the first lens, helping to provide a higher efficiency of light use.
Optionally, according to an embodiment of the present invention, in the above proposed automotive lighting system for a vehicle, the light entrance surface of the first lens is shaped to be convex towards the light source and has its center located at the optical axis of the automotive lighting system. Besides, in a direction parallel to the optical axis of the automotive lighting system, the first light entrance face of the first protrusion is located at a same position as the center of the light entrance surface of the first lens. In other words, in a longitudinal direction parallel to the optical axis of the automotive lighting system, the first light entrance face of the first protrusion keeps flush with the center of the first lens' light entrance surface. This helps to increase further the efficiency of light in-coupling from the light source into the first lens especially at a periphery of the first lens, because the distance between the first light entrance face of the first protrusion and the first sub light source is reduced significantly at least to be equal to the distance between the center of the first lens' light entrance surface and the respective second sub light source on or near the optical axis of the automotive lighting system.
According to a second aspect of the present invention, an automotive lighting system is proposed for use as well in a vehicle. As similar to the automotive lighting system proposed in the first aspect of the present invention, according to the second aspect of the present invention, the automotive lighting system for use in a vehicle comprises a light source, a first lens and a second lens too. In a similar way, the first lens comprises a light entrance surface and a light exit surface, the first lens is configured to receive light from the light source at the light entrance surface and refract it onto the second lens, and the second lens is configured to receive light from the first lens and project it towards a road in front of the vehicle. The difference lies in that, in the automotive lighting system according to the second aspect of the present invention, the light source comprises not only a first sub light source but also a second sub light source, and accordingly, the light entrance surface of the first lens is provided not only with a first protrusion to receive light from the first sub light source but also with a second protrusion to receive light from the second sub light source. Besides, according to the second aspect of the present invention, in the above proposed automotive lighting system for a vehicle, the first protrusion, now not necessarily located at a periphery but at any position of the light entrance surface of the first lens, comprises a first light entrance face and, opposite thereto, a first light exit face in contact with the light entrance surface of the first lens. A similar configuration applies to the second protrusion as well, meaning that the second protrusion, located at any position of the light entrance surface of the first lens, comprises a second light entrance face and, opposite thereto, a second light exit face in contact with the light entrance surface of the first lens. Furthermore, a partial overlapping exists between the first light exit face of the first protrusion and the second light exit face of the second protrusion, such that the second lens projects light from the first and second sub light sources on the road in front of the vehicle as a light pattern with a first maximum light intensity I_max1, a second maximum light intensity I_max2, and a minimum light intensity I_min between the first maximum light intensity I_max1 and the second maximum light intensity I_max2, where I_min/I_max1 > 90% and I_min/I_max2 > 90%.
As can be seen, in the above automotive lighting system for a vehicle according to the second aspect of the present invention, two protrusions, i.e., the first and second protrusions, are provided on the light entrance surface of the first lens, and light exit faces of the two protrusions (i.e., the first light exit face of the first protrusion and the second light exit face of the second protrusion) are adapted to have a partial overlapping. As recited in detail above, the partial overlapping between the light exit faces of the two protrusions helps to render the final light pattern projected by the second lens in front of the vehicle from the first and second sub light sources to have a uniform distribution of light intensity. To be precise, the final light pattern projected by the above automotive lighting system is a superposition result of two sub light patterns, which are projected by the second lens from the first and second sub light sources respectively. According to the second aspect of the present invention, in the final light pattern from the automotive lighting system, a first maximum light intensity I_max1 exists around the center of the first sub light pattern from the first sub light source, a second maximum light intensity I_max2 exists around the center of the second sub light pattern from the second sub light source, and a minimum light intensity I_min exists between the first maximum light intensity I_max1 and the second maximum light intensity I_max2, where I_min/I_min1>90% and I_min/I_max2>90%. In this way, undesired visible gaps between the two sub light patterns, which are projected by the second lens in front of the vehicle from the first and second sub light sources respectively, can be suppressed and preferably eliminated, thereby providing the final light pattern projected by the automotive lighting system with a perfect appearance where gaps between images of adjacent sub light sources or adjacent pixels are nicely closed.
Preferably, according to an embodiment, in the above automotive lighting system for a vehicle proposed by the second aspect of the present invention, the partial overlapping between the first light exit face of the first protrusion and the second light exit face of the second protrusion is less than half of the first light exit face of the first protrusion and further less than half of the second light exit face of the second protrusion. In other words, overlapping between the two protrusions, specifically between the light exit faces thereof, is kept to be less than 50 percent of each light exit face. In this way, a favorable effect of superposition between adjacent sub light patterns from adjacent sub light sources can be obtained, so as to provide the final light beam with a uniform distribution of light intensity and to close or suppress effectively the gaps between images of adjacent sub light sources or adjacent pixels.
Optionally, according to an embodiment, in the above automotive lighting system for a vehicle proposed by the second aspect of the present invention, at least one of the first light entrance face of the first protrusion and the second light entrance face of the second protrusion comprises a flat face perpendicular to an optical axis of the automotive lighting system. In other words, the first protrusion and/or the second protrusion are provided with a flat light entrance face perpendicular to the optical axis of the automotive lighting system. This helps to keep the distance between each protrusion and its respective sub light source to be constant and preferably to be relatively small for example across the light entrance surface of the first lens, thus being beneficial for providing a high efficiency of light in-coupling across the whole light entrance surface of the first lens.
Further optionally, according to another embodiment, in the above proposed automotive lighting system for a vehicle, at least one of the first light entrance face of the first protrusion and the second light entrance face of the second protrusion is designed in a rectangle, round, triangle, or polygon contour. Besides, according to still another embodiment, in the above proposed automotive lighting system, at least one of the first light exit face of the first protrusion and the second light exit face of the second protrusion is designed in a rectangle or trapezoidal contour. It should be noted herein that all the above contours listed with regard to the light entrance or exit face of the first or second protrusion are merely provided for the purpose of illustrating the present invention, and should never be deemed as a limitation or restriction to it. Having benefited from the teaching of the present invention, a skilled person in the art shall easily think of any other shapes or contours applicable to the light entrance or exit face of the two protrusions, and all these alternatives shall be encompassed within the scope of the present invention.
Furthermore, according to another embodiment of the present invention, in the proposed automotive lighting system for a vehicle, the first protrusion comprises a curved side face being contiguous to the first light entrance face at one end and to the first light exit face at the other end. For example, the first protrusion can be provided with a cylindrical side surface. A similar configuration applies to the second protrusion as well, i.e., the second protrusion comprises a curved side face being contiguous to the second light entrance face at one end and to the second light exit face at the other end. Thus, for example the second protrusion comprises a cylindrical side surface too.
Alternatively, according to yet another embodiment of the present invention, in the proposed automotive lighting system for a vehicle, the first protrusion comprises more than two flat side faces each being contiguous to the first light entrance face at one end and to the first light exit face at the other end. As an example, the first protrusion can be provided with a prismatic side surface. A similar configuration applies to the second protrusion as well, i.e., the second protrusion comprises more than two flat side faces each being contiguous to the second light entrance face at one end and to the second light exit face at the other end. In this case, for example, the second protrusion comprises a prismatic side surface too. Optionally, according to an example instance of the above embodiment, at least one of the flat side faces of the first or second protrusion encloses an acute angle with respect to the light entrance surface of the first lens, thus helping to ensure the partial overlapping between the light exit faces of the two protrusions.
Furthermore, according to an optional embodiment, the automotive lighting system for a vehicle proposed above in the first or second aspect of the present invention also comprises a third lens. To be specific, the third lens is configured to receive light from the light exit surface of the first lens and project it onto the second lens. In other words, the third lens is located at an optically midway position between the first lens and the second lens, which is beneficial for providing a greater flexibility for example in beam shaping.
It should be noted that different configurations are utilized for the automotive lighting system in the above two aspects of the present invention, where the first one involves only a periphery position of at least one protrusion on the light entrance surface of the first lens, and the second one involves only a partial overlapping between light exit faces of two protrusions. This provides a possibility that the two configurations can be used respectively in two separate automotive lighting systems, i.e., the two proposed in the above mentioned first and second aspects of the present invention. However, this way of separate description shall be never deemed to limit the present invention only to the above two cases, i.e., using two configurations of the automotive lighting system independently. As a matter of fact, the present inventors have found that the above two configurations, involving the periphery position of at least one protrusion and the partial overlapping between light exit faces of two protrusions respectively, can be combined as well into one single automotive lighting system, and such an alternative aspect shall be encompassed as well within the scope of the present invention. Besides, this also renders it easy for a skilled person in the art to consider combining those preferred or optional improvements as made to each configuration of the automotive lighting system in the first or second aspect of the present invention in any feasible ways.
It will be appreciated by a skilled person 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 automotive lighting system for a vehicle can be carried out by a skilled person in the art based on the disclosure of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the present invention will be described in the following in more details, with reference to the appended drawings showing embodiments and forming part of the present invention. In the drawings:

Fig. 1 schematically illustrates an automotive lighting system for a vehicle according to an embodiment of the present invention, where a first protrusion is provided at a periphery of the light entrance surface of the first lens;
Fig. 2 schematically illustrates an automotive lighting system for a vehicle according to an embodiment of the present invention, where a third lens is introduced at an optically midway position between the first lens and the second lens;
Fig. 3 schematically illustrates an automotive lighting system for a vehicle according to an embodiment of the present invention, where a partial overlapping exists between light exit faces of two adjacent protrusions; and
Fig. 4 schematically illustrates an exemplary simulated result in the distribution of light intensity for the final light pattern projected by the second lens in front of the vehicle from the first and second sub light sources, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

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 only considered as exemplary of the basic principle of the present invention but not intended to limit the present invention merely 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 Fig. 1, an automotive lighting system is proposed for use for example in a vehicle, according to a first aspect of the present invention. The automotive lighting system 1 comprises a light source 11, a first lens 12 and a second lens 13, wherein the light source 11 comprises at least a first sub light source 111, such as an LED. Optionally, as shown in Fig. 1, the first sub light source 111 is located at an off-axis position with respect to the optical axis L of the automotive lighting system 1, for example close to an upper edge of the first lens 12. Turning to the first lens 12 of the automotive lighting system 1 in Fig. 1, it comprises a light entrance surface 121 (i.e., the right side in the drawing) and a light exit surface 122 (i.e., the left side in the drawing), wherein a first protrusion 141 is further provided on the light entrance surface 121 of the first lens 12, especially at a periphery thereof. For example, as seen in Fig. 1, the first protrusion 141 is located at an upper edge of the light entrance surface 121 of the first lens 12. In this way, light emitted by the light source 11, especially by the first sub light source 111, is incident onto the first protrusion 141 before entering the first lens 12 at an optically downstream position. To be specific, the first protrusion 141 comprises a first light entrance face 1411 (i.e., the right face in the drawing) and a first light exit face 1412 (i.e., the left face in the drawing), where light from the first sub light source 111 is incident firstly onto the first light entrance face 1411, refracted thereby, and gets inside the first protrusion 141. Particularly, light may undergo several times of total internal reflection while propagating within the first protrusion 141, and gets refracted out leftwards for example at the first light exit face 1412 of the first protrusion 141, thereby entering the first lens 12.
As seen from above, in the automotive lighting system 1 proposed by the present invention, light emitted from the light source 11, for example from the first sub light source 111, will be only incident into the first lens 12 after they pass through the first protrusion 141 which is positioned ahead in the optical path. In this way, as compared with a case where no protrusion being deployed, the in-coupling surface for the light from the first sub light source 111 is obviously moved forwards in an optically upstream direction, i.e., from the light entrance surface 121 of the first lens 12 to the first light entrance face 1411 of the first protrusion 141. This forward moving of the in-coupling surface compensates nicely the larger distance at the edge of the first lens 12 that would exist otherwise between the first sub light source 111 and the light entrance surface 121 of the first lens 12 if no protrusion is provided, for example due to a curvature in the light entrance surface 121 of the first lens 12 (especially being convex in the optically upstream direction). This finally helps to increase the efficiency of light in-coupling from the light source 11 into the first lens 12, and to reduce the light loss at the edge of the first lens 12. Advantageously, the present inventors have also found that a maximum efficiency of light in-coupling can be obtained, if the first light exit face 1412 of the first protrusion 141 is chosen to be 1 to 4 times larger than the first light entrance face 1411 of the first protrusion 141.
In view of above, according to a most preferable embodiment of the present invention, a plurality of first protrusions 141 can be introduced, which are for example equally spaced along a periphery of the light entrance surface 121 of the first lens 12, so as to increase the efficiency of light in-coupling and accordingly reduce the light loss at the edges of the automotive lighting system 1. In the end, under the help of the second lens 13, light from the light source 11 (such as from the first sub light source 111) is projected onto a road in front of the vehicle after passing through the first protrusion 141 and the first lens 12. Preferably, the second lens 13, located at an optically last position in the automotive lighting system 1, comprises a projection lens.
Further optionally, as shown in Fig. 1 as well, in the automotive lighting system 1, the light source 11 also comprises one or more second sub light sources 112, such as two LEDs in the drawing. In this case, as an example, the first sub light source 111 and the second sub light sources 112 can be distributed in an array, such as in a column perpendicular to the optical axis L of the automotive lighting system 1. Correspondingly, one or more second protrusions 142 are introduced as well on the light entrance surface 121 of the first lens 12, where each of the second protrusions 142 is configured to receive light from a respective second sub light source 112. As illustrated in Fig. 1, in a direction perpendicular to the optical axis L of the automotive lighting system 1, each second protrusion 142 is deployed at a same position as its respective second sub light source 112, which ensures a larger efficiency of light in-coupling from each second sub light source 112 into the respective second protrusion 142 and gives a minimum loss of light across the whole light entrance surface 121 of the first lens 12. Again, as similar to the first protrusion, by setting the left light exit face of the second protrusion 142 to be 1 to 4 times larger than the right light entrance face of the second protrusion 142, a maximum efficiency of light in-coupling can be obtained from the second sub light source 112 into the respective second protrusion 142.
It should be noted herein that the number of first light sources 111 (being one) and the number of second light sources 112 (being two) are listed merely as examples to help illustrating the constitution of the light source 11 schematically, and should never be deemed to limit the present invention only thereto. In other words, the number of the first light sources 111 or the second light sources 112 can be any other numbers as well, distributed for example in an array perpendicular to the optical axis L of the automotive lighting system 1. Correspondingly, the respective first and second protrusions 141, 142 can be provided across the light entrance surface 121 of the first lens 12 in a similar array distribution.
With reference to Fig. 2, an automotive lighting system according to another embodiment of the present invention is illustrated. Most of the components in the automotive lighting system 1 of Fig. 2 keep the same as in the automotive lighting system 1 of Fig. 1, and thus the same reference numbers are used to indicate the same elements. Differences between the automotive lighting systems 1 of Fig. 1 and Fig. 2 are reflected in the following two aspects.
On one hand, in the automotive lighting system 1 of Fig. 2, a third lens 15 is introduced, such as at an optically midway position between the first lens 12 and the second lens 13, which third lens 15 is configured to receive light from the first lens 12 and redirect it onto the second lens 13. With the incorporation of the third lens 15, more flexibility can be provided for example in shaping of the light beam as projected finally by the automotive lighting system 1 in front of the vehicle. Having benefited from the teaching of the present invention, those skilled in the art shall easily think of different shapes and/or configurations that are suitable for the third lens 15 and all these implementations should be encompassed within the scope of the present invention.
On the other hand, as shown in the automotive lighting system 1 of Fig. 2, the light entrance surface 121 of the first lens 12 is symmetrically convex in the optically upstream direction, especially has its center C located at the optical axis L of the automotive lighting system 1. Furthermore, as seen in Fig. 2, in a direction parallel to the optical axis L of the automotive lighting system, i.e., the horizontal direction in the drawing, the first light entrance face 1411 of the first protrusion 141 is located at the same position as the center C of the light entrance surface 121 of the first lens 12. This means that the first light entrance face 1411 of the first protrusion 141 is spaced apart from the respective first sub light source 111 by such a distance that equals the one between the center C of the light entrance surface 121 of the first lens 12 and the respective second sub light source 112 located at the optical axis L of the automotive lighting system 1. This kind of flush-positioned configuration between the center C of the light entrance surface 121 of the first lens 12 and the first light entrance face 1411 of the first protrusion 141 is helpful to keep the efficiency of light in-coupling to be uniform across the light entrance surface 121 of the first lens 12, and thus beneficial for obtaining a uniform intensity distribution in the final light pattern projected in front of the vehicle. In a similar consideration, the flush-positioned configuration as mentioned above applies as well between the center C of the light entrance surface 121 of the first lens 12 and the light entrance face of the second protrusion 142, and no detailed explanation will be repeated herein for the sake of conciseness.
With reference to Fig. 3, an automotive lighting system is proposed for use for example in a vehicle, according to a second aspect of the present invention. Most of the components in the automotive lighting system 1 of Fig. 3 keep the same as in the automotive lighting system 1 of Fig. 1, and thus the same reference numbers are used to indicate the same elements, such as the first protrusion 141 at a periphery of the light entrance surface 121 of the first lens 12. Differences between the automotive lighting systems 1 of Fig. 1 and Fig. 3 lie in the following two aspects.
On one hand, in the automotive lighting system 1 of Fig. 3, a third lens 15 is introduced, such as at an optically midway position between the first lens 12 and the second lens 13. As similar to the description above about Fig. 2, the third lens 15 in the automotive lighting system 1 of Fig. 3 is configured as well to receive light from the first lens 12 and redirect it onto the second lens 13, thus enabling greater flexibility in for example beam shaping of the final light pattern projected in front of the vehicle.
On the other hand, in the automotive lighting system 1 of Fig. 3, the two adjacent protrusions, i.e., the first protrusion 141 and the second protrusion 142 are closely positioned such that there is a partial overlapping between light exit faces thereof. As similar to the above description with respect to Fig. 1, the first protrusion 141 in the automotive lighting system 1 of Fig. 3 comprises a first light entrance face 1411 and a first light exit face 1412 as well. In a similar way, the second protrusion 142 also comprises a second light entrance face 1421 and a second light exit face 1422, see Fig. 3. As to the partial overlapping, it is the partial overlapping 1400 between the first light exit face 1412 of the first protrusion 141 and the second light exit face 1422 of the second protrusion 142. The first light exit face 1412 of the first protrusion 141, the second light exit face 1422 of the second protrusion 142, and the partial overlapping 1400 therebetween are shown clearly in the automotive lighting system 1 of Fig. 3. As depicted in Fig. 3, the first light exit face 1412 of the first protrusion 141 has an upper boundary at point a and a lower boundary at point c, while the second light exit face 1422 of the second protrusion 142 has an upper boundary at point b and a lower boundary at point d, wherein the segment between points b and c acts as the partial overlapping 1400.
Moreover, according to the second aspect of the present invention, the partial overlapping 1400 as mentioned above between the first light exit face 1412 of the first protrusion 141 and the second light exit face 1422 of the second protrusion 142 is configured in such a way that the second lens 13 projects light from the first and second sub light sources 111, 112 on the road in front of the vehicle as a light pattern with a first maximum light intensity I_max1, a second maximum light intensity I_max2, and a minimum light intensity I_min between the first maximum light intensity I_max1 and the second maximum light intensity I_max2, where I_min/I_max1 > 90% and I_min/I_max2 > 90%, leading to a uniform distribution of light intensity across the final light pattern. Details about the final light pattern as projected by the automotive lighting system in front of the vehicle will be explained in the following with reference to Fig. 4, where an example simulated result in the distribution of light intensity for the final light pattern are illustrated according to an embodiment of the present invention.
As shown in Fig. 4, the final light pattern as projected by the second lens 13 from the first and second sub light sources 111, 112 comprises a first maximum light intensity I_max1 and a second maximum light intensity I_max2, located respectively at points A and B. Besides, in the final light pattern of Fig. 4, especially on a connecting line between the first and second maximum light intensity I_max1, I_max2, there is also a minimum light intensity I_min, located at point C, where I_min/I_max1 > 90% and I_min/I_max2 > 90%. From the perspective of generation, the final light pattern, as shown in Fig. 4 and generated for example by the automotive lighting system 1 of Fig. 3, is a superposition result between two sub light patterns, which two sub light patterns are projected by the second lens 13 from the first sub light source 111 and the second sub light source 112 respectively, and comprise their own centers in light intensity located around points A and B respectively. According to the second aspect of the present invention, a special overlapping is introduced between the first light exit face 1412 of the first protrusion 141 and the second light exit face 1422 of the second protrusion 142, as so to obtain an uniform superposition result between the two sub light patterns, leading to the final light pattern having two peaks I_max1, I_max2 of light intensity around centers of the two sub light patterns and also a minimum light intensity I_min between the two peaks I_max1, I_max2, which minimum light intensity I_min is also larger than 90 percent of each peak I_max1, I_max2. This helps to ensure that the final light pattern as projected by the automotive lighting system 1 in front of the vehicle is uniformly distributed in light intensity, and furthermore gaps that would otherwise exist between the two sub light patterns from the two sub light sources can be nicely closed. This perfect uniform distribution of light intensity in the final light pattern can be expressed as well by a special relationship between an average light intensity I_ave within the pattern countour of the final light pattern (indicated for example by a dashed rectangle in Fig. 4) and the two peaks I_max1, I_max2 of light intensity as mentioned above, for example by I_ave/I_max1 > 0.4 and I_ave/I_max2 > 0.4.
Preferably, according to the second aspect of the present invention, in an example instance of the above embodiment, the partial overlapping 1400 between the first light exit face 1412 of the first protrusion 141 and the second light exit face 1422 of the second protrusion 142 is less than half of the first light exit face 1412 of the first protrusion 141, and also less than half of the second light exit face 1422 of the second protrusion 142. In this way, the difference between the first or second maximum light intensity I_max1, I_max2 and the minimum light intensity I_min is greatly reduced, helping to provide the final light pattern projected by the automotive lighting system 1 in front of the vehicle with an even more uniform distribution of light intensity.
It should also be noted that the above-mentioned embodiments illustrate rather than limit the present invention, and that a skilled person 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, a skilled person in the art would recognize that various features of the described embodiments may be combined in accordance with the present 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.

LIST OF REFERENCE NUMERALS

1 automotive lighting system
11 light source
111 first sub light source
112 second sub light source
12 first lens
121 light entrance surface of first lens
122 light exit surface of first lens
13 second lens
141 first protrusion
1411 first light entrance face of first protrusion
1412 first light exit face of first protrusion
142 second protrusion
1421 second light entrance face of second protrusion
1422 second light exit face of second protrusion
1400 overlapping between first light exit face of first protrusion and second light exit face of second protrusion
a upper boundary of first light exit face of first protrusion
b upper boundary of second light exit face of second protrusion
c lower boundary of first light exit face of first protrusion
d lower boundary of second light exit face of second protrusion
L optical axis of automotive lighting system
C center of light entrance surface of first lens
15 third lens
A position of first maximum light intensity I_max1
B position of second maximum light intensity I_max2
C position of minimum light intensity I_min

Claims

An automotive lighting system (1) for a vehicle, comprising:
a light source (11) comprising a first sub light source (111),

a first lens (12) comprising a light entrance surface (121) and a light exit surface (122), and

a second lens (13),

the first lens (12) being configured to receive light from the light source (11) at the light entrance surface (121) and refract it onto the second lens (13),

the second lens (13) being configured to receive light from the first lens (12) and project it towards a road in front of the vehicle, and

the light entrance surface (121) of the first lens (12) being provided with a first protrusion (141) to receive light from the first sub light source (111), where the first protrusion (141) is located at a periphery of the light entrance surface (121) of the first lens (12) with respect to an optical axis (L) of the automotive lighting system (1).
The automotive lighting system (1) for a vehicle according to claim 1, wherein the first sub light source (111) is located at an off-axis position with respect to the optical axis (L) of the automotive lighting system (1).
The automotive lighting system (1) for a vehicle according to claim 1 or 2, wherein
the light source (11) comprises a plurality of second sub light sources (112), which are distributed in an array along with the first sub light source (111),
the light entrance surface (121) of the first lens (12) is provided with a plurality of second protrusions (142), which are distributed in an array along with the first protrusion (141) across the light entrance surface (121) of the first lens (12), and
each of the plurality of second protrusions (142) is configured to receive light from a respective one of the plurality of second sub light sources (112).
The automotive lighting system (1) for a vehicle according to claim 1 or 2, wherein
the first protrusion (141) comprises a first light entrance face (1411) and, opposite thereto, a first light exit face (1412) in contact with the light entrance surface (121) of the first lens (12), where
the first light exit face (1412) of the first protrusion (141) is 1 to 4 times larger than the first light entrance face (1411) of the first protrusion (141).
The automotive lighting system (1) for a vehicle according to claim 4, wherein
the light entrance surface (121) of the first lens (12) is shaped to be convex towards the light source (11) with its center (C) located at the optical axis (L) of the automotive lighting system (1), and,
in a direction parallel to the optical axis (L) of the automotive lighting system (1), the first light entrance face (1411) of the first protrusion (141) is located at a same position as the center (C) of the light entrance surface (121) of the first lens (12).
An automotive lighting system (1) for a vehicle, comprising:
a light source (11) comprising a first sub light source (111) and a second sub light source (112),

a first lens (12) comprising a light entrance surface (121) and a light exit surface (122), and

a second lens (13),

the first lens (12) being configured to receive light from the light source (11) at the light entrance surface (121) and refract it onto the second lens (13),

the second lens (13) being configured to receive light from the first lens (12) and project it towards a road in front of the vehicle, and

the light entrance surface (121) of the first lens (12) being provided with a first protrusion (141) to receive light from the first sub light source (111) and a second protrusion (142) to receive light from the second sub light source (112),

the first protrusion (141) comprising a first light entrance face (1411) and, opposite thereto, a first light exit face (1412) in contact with the light entrance surface (121) of the first lens (12),

the second protrusion (142) comprising a second light entrance face (1421) and, opposite thereto, a second light exit face (1422) in contact with the light entrance surface (121) of the first lens (12), and

a partial overlapping (1400) exists between the first light exit face (1412) of the first protrusion (141) and the second light exit face (1422) of the second protrusion (142), such that the second lens (13) projects light from the first and second sub light sources (111, 112) on the road in front of the vehicle as a light pattern with a first maximum light intensity I_max1, a second maximum light intensity I_max2, and a minimum light intensity I_min between the first maximum light intensity I_max1 and the second maximum light intensity I_max2, where I_min/I_max1 > 90% and I_min/I_max2 > 90%.
The automotive lighting system (1) for a vehicle according to claim 6, wherein
the partial overlapping (1400) between the first light exit face (1412) of the first protrusion (141) and the second light exit face (1422) of the second protrusion (142) is less than half of the first light exit face (1412) of the first protrusion (141) and further less than half of the second light exit face (1422) of the second protrusion (142).
The automotive lighting system (1) for a vehicle according to claim 6 or 7, wherein
at least one of the first light entrance face (1411) of the first protrusion (141) and the second light entrance face (1421) of the second protrusion (142) comprises a flat face perpendicular to an optical axis (L) of the automotive lighting system (1).
The automotive lighting system (1) for a vehicle according to claim 6 or 7, wherein
at least one of the first light entrance face (1411) of the first protrusion (141) and the second light entrance face (1421) of the second protrusion (142) is designed in a rectangle, round, triangle, or polygon contour.
The automotive lighting system (1) for a vehicle according to claim 6 or 7, wherein
at least one of the first light exit face (1412) of the first protrusion (141) and the second light exit face (1422) of the second protrusion (142) is designed in a rectangle or trapezoidal contour.
The automotive lighting system (1) for a vehicle according to claim 6 or 7, wherein
the first protrusion (141) comprises a curved side face being contiguous to the first light entrance face (1411) at one end and to the first light exit face (1412) at the other end, or
the second protrusion (142) comprises a curved side face being contiguous to the second light entrance face (1421) at one end and to the second light exit face (1422) at the other end.
The automotive lighting system (1) for a vehicle according to claim 6 or 7, wherein
the first protrusion (141) comprises more than two flat side faces each being contiguous to the first light entrance face (1411) at one end and to the first light exit face (1412) at the other end, or
the second protrusion (142) comprises more than two flat side faces each being contiguous to the second light entrance face (1421) at one end and to the second light exit face (1422) at the other end.
The automotive lighting system (1) for a vehicle according to claim 12, wherein
at least one of the flat side faces encloses an acute angle with respect to the light entrance surface (121) of the first lens (12).
The automotive lighting system (1) for a vehicle according to claim 1 or 6, further comprising:
a third lens (15), which is configured to receive light from the light exit surface (122) of the first lens (12) and project it onto the second lens (13).
The automotive lighting system (1) for a vehicle according to claim 1 or 6, wherein
the light source (11) is configured to provide a matrix high beam pattern.