Patent Publication Number: US-2023160552-A1

Title: Lighting device for vehicles

Description:
This nonprovisional application claims priority under 35 U.S.C. § 119(a) to German Patent Application No. 10 2021 130 729.5, which was filed in Germany on Nov. 24, 2021, and which is herein incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a lighting device for vehicles having a light source, having an optical element which is associated with the light source and which is designed as a reflection lens which, in a central region accommodating an optical axis of the optical element, has a lens section which has a first coupling-in surface on a coupling-in side and a first coupling-out surface on a coupling-out side, wherein light coupled in at the first coupling-in surface can be guided directly to the first coupling-out surface, and which has, in an outer region, a reflection section which has a second coupling-in surface on a coupling-in side and a second coupling-out surface on a coupling-out side, wherein light coupled in at the second coupling-in surface can be guided to the second coupling-out surface via a reflection surface of the optical element. 
     Description of the Background Art 
     A lighting device for vehicles having a light source and an optical element is known from DE 10 2019 118 051 A1, wherein the optical element has a reflection section, on the one hand, and a lens section, on the other hand. The reflection section is located behind the lens section in the main emission direction. In an intermediate region between the reflection section and the lens section, an imaging edge generated by lasering is introduced, which is imaged to a cut-off line of a light distribution by means of the lens section. A disadvantage of the known optical element is that it has a relatively large overall depth. 
     A lighting device for vehicles having a light source and an optical element is known from DE 10 2017 213 516 A1, wherein the optical element is designed as a reflection lens having a reflection section and a lens section. The lens section is located in a central region of the optical element and the reflection section is located in an outer region of the optical element. A coupling-out surface of the reflection section directly adjoins a coupling-out surface of the lens section. The reflection section has a reflection surface on which coupled-in light is totally reflected in the main emission direction. The optical element is formed substantially rotationally symmetric. The light source is arranged on an optical axis of the optical element and arranged oriented in the main emission direction of the lighting device. The lighting device does not have means to image a cut-off line for a light distribution. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a lighting device for vehicles containing a reflection lens in such a way that a high light efficiency is provided for a light distribution with a cut-off line in a space-saving manner. 
     To achieve the object, the invention in an exemplary embodiment, provides that the light source is tilted with respect to an axis of rotation running perpendicular to the optical axis and/or is arranged rotated about the optical axis in the plane running perpendicular to the optical axis, with the formation of an obliquely running edge of the light source, and in that the first coupling-in surface, the second coupling-in surface, the reflection surface, the first coupling-out surface, and/or the second coupling-out surface of the optical element are shaped in such a way that the predetermined light distribution is produced with imaging of the edge of the light source as a cut-off line. 
     A first coupling-in surface, a second coupling-in surface, a reflection surface, a first coupling-out surface, and/or a second coupling-out surface of the reflection lens can be formed non-rotationally symmetrically such that the light emitted from a tilted and/or rotated light source is imaged according to the predetermined light distribution with a cut-off line. Advantageously, a light distribution can be generated in a simple way without the need for further components, in particular a shading element for imaging the cut-off line. The tilted or rotated arrangement of the light source in conjunction with the aforementioned surfaces of the reflection lens can significantly increase the light yield. The light efficiency can be at least 60%, preferably 70% to 80%. This means that at least 60% of the luminous flux emitted by the light source is coupled out at the light exit side of the optical element. 
     A lens section and/or a reflection section of the optical element may not be formed rotationally symmetric. In particular, the lens section and the reflection section can be formed extended in a plane running perpendicular to the optical axis of the optical element, preferably in the horizontal direction. Thus, an upper and a lower part of the reflection surface are larger than a left and a right part of the reflection surface. The coupling-in surface and the coupling-out surface of the lens section are preferably formed oval-shaped in cross section. Advantageously, this can produce a relatively broad light distribution, which is preferably used to illuminate a forefield of the headlight. 
     An upper part and a lower part of the reflection surface can be formed with different parabolic shapes. The light source is tilted upward by an acute angle so that essentially the upper part of the reflection surface is captured. This makes it possible to generate a relatively broad distribution below a zero line of the light distribution. 
     A recess can be provided in an upper region of the reflection section, namely, in a reflection surface end region facing the optical axis. This recess causes the edge of the light source to be sharply imaged as the cut-off line of the light distribution. This recess prevents part of the light emitted by the light source from hitting the upper part of the reflection surface, and thereby leading to a softening of the cut-off line, in particular to the imaging of a light component above the desired cut-off line. Advantageously, a central region of the cut-off line between −5° and +5° in the horizontal can be sharply imaged. 
     The lens section and/or the rotation section can be formed rotationally symmetric, wherein the optical element is formed cut off above the lens section. As a result, the upper part of the reflection surface is smaller than the lower part of the same. Because the light source is tilted downward, namely, in the direction of the lower part of the reflection surface, mainly only the lower part of the reflection surface is used for total reflection. Advantageously, this can produce a long-range light distribution with essentially light emission above a zero line. By rotating the light source about the optical axis, the slope of the cutoff line can also be adjusted, wherein the angular position of the upper edge of the light source defines the cut-off line. 
     The lens section and/or the reflection section can be formed rotationally symmetric. The light source is arranged oriented in the direction of the optical axis so that a symmetric light distribution, in particular a high beam distribution, can be generated hereby with respect to a vertical line. 
     The lighting device can have three light modules each containing a light source and an optical element. A high beam light module has substantially a rotationally symmetric lens section and a reflection section, wherein the light source is arranged oriented in the direction of the optical axis. A long-range light module has a substantially rotationally symmetric lens section and reflection section, wherein the reflection section is formed cut off above the lens section. By orienting the light source in the direction of the reflection section below an optical axis, most of the coupled-out light is coupled out after total reflection at the reflection surface above a horizontal line, so that a long-range light distribution is produced. A forefield light module is formed substantially of a lens section extended in the horizontal direction and an extended reflection section. The light source is designed tilted. In this way, a forefield light distribution can be generated in which the light is mainly coupled out under a horizontal plane. A low-beam distribution can be generated by superimposing the forefield and long-range light distribution. A high-beam distribution can be generated by additionally turning on the high beam module. Advantageously, the three light modules can be used to construct a completely functional headlight which has a small overall depth and requires little installation space. The optical elements are each designed as a single piece and enable efficient light control with a high optical efficiency. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes, combinations, and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein: 
         FIG.  1    shows a schematic representation of a headlight with three light modules; 
         FIG.  2    shows a front view of an optical element of a high beam module; 
         FIG.  3    shows a top view of the optical element of the high beam module; 
         FIG.  4    shows a bottom view of the optical element of the high beam module; 
         FIG.  5    shows a vertical cross section of the optical element from  FIG.  2   ; 
         FIG.  6    shows a horizontal cross section of the optical element along the optical element of the high beam module along from  FIG.  2   ; 
         FIG.  7    shows a front view of an optical element of the long-range light module; 
         FIG.  8    shows a top view of the optical element of a long-range light module according to  FIG.  7   ; 
         FIG.  9    shows a bottom view of the optical element of a long-range light module according to  FIG.  7   ; 
         FIG.  10    shows a vertical cross-section of the optical element from  FIG.  7   ; 
         FIG.  11    shows a horizontal cross-section of the optical element from  FIG.  7   ; 
         FIG.  12    shows a front view of an optical element of a forefield light module; 
         FIG.  13    shows a top view of the optical element of a long-range light module according to  FIG.  12   ; 
         FIG.  14    shows a bottom view of the optical element of a long-range light module according to  FIG.  12   ; 
         FIG.  15    shows a vertical cross section of the optical element from  FIG.  12   ; 
         FIG.  16    shows a horizontal cross section of the optical element from  FIG.  12   ; 
         FIG.  17    shows a schematic light distribution of the high beam module; 
         FIG.  18    shows a schematic light distribution of the long-range light module; 
         FIG.  19    shows a schematic light distribution of the forefield light module; and 
         FIG.  20    shows a schematic representation of a light distribution with the forefield and long-range light module turned on. 
     
    
    
     DETAILED DESCRIPTION 
     The lighting device for vehicles is designed as a headlight with a housing  1  and with a transparent cover plate  2  closing an opening of housing  1 . Cover plate  2  is preferably formed crystal clear. 
     Three light modules are arranged within housing  1 . On the one hand, a high beam module  3 , on the other hand, a long-range light module  4 , and furthermore a forefield light module  5  are provided. 
     Light modules  3 ,  4 ,  5  each have a light source  6 ,  7 ,  8  and an optical element  9 ,  10 ,  11 . Optical elements  9 ,  10 ,  11  are each formed in one piece. They are each designed as reflection lenses in which light, on the one hand, is imaged by a lens section and, on the other hand, is totally reflected by means of a reflection section within optical element  9 ,  10 ,  11  and is coupled out into a coupling-out surface arranged adjacent to the lens section. 
     Optical elements  9 ,  10 ,  11  each have a coupling-in side  12  and a coupling-out side  13 . Coupling-in side  12  is formed on a side facing light source  6 ,  7 ,  8 . Coupling-out side  13  is arranged in front of coupling-in side  12  in the main emission direction H of the headlight. The lens section of optical elements  9 ,  10 ,  11  is arranged in a central region of optical element  9 ,  10 ,  11 . The reflection section is arranged in an outer region of optical element  9 ,  10 ,  11 . Thus, the lens section is arranged in a region close to an optical axis A of optical element  9 ,  10 ,  11 , and the reflection section is arranged in a region far from the optical axis A. 
     High beam module  3  is used to generate a high beam distribution according to  FIG.  17   . High beam module  3  has light source  6  arranged on the optical axis A and aligned oriented in the direction of optical element  9 . A main axis H 1  of the light source  6  runs in the direction of the optical axis A. 
     Optical element  9  of high beam module  3  is formed substantially rotationally symmetric. It has a lens section  14  in the central region and a reflection section  15  in an outer region. Lens section  14  is arranged rotationally symmetric to the optical axis A. Lens section  14  intersects the optical axis A and is located in a region close to the optical axis A. Reflection section  15  is located in a region remote from the optical axis A and does not intersect the optical axis A. 
     Lens section  14  is formed as a plano-convex lens having a planar first coupling-in surface  16  and a convex first coupling-out surface  17 . Reflection section  15  directly adjoins lens section  14  transversely to the optical axis A. Reflection section  15  has a second coupling-in surface  18  and a second coupling-out surface  19 . Optical element  9  has an indentation  20  on coupling-in side  12 , so that the second coupling-in surface  18  is parallel and/or slightly inclined to the optical axis A. Indentation  20  can be conical or cylindrical. A lateral surface of indentation  20  serves here as a second coupling-in surface  18  of optical element  9 . 
     Reflection section  15  has an arc-shaped reflection surface  21  which widens in the main emission direction H and can be formed, for example, in the shape of a paraboloid or as a free-form surface. Light coupled in at the second coupling-in surface  18  of reflection section  15  is reflected at reflection surface  21  and coupled out at the second coupling-out surface  19 . Preferably, there is only one total reflection of the light rays at reflection surface  21 . 
     By superimposing the light coupled out at the first coupling-out  17  and at the second coupling-out surface  19  of optical element  9 , the high beam distribution according to  FIG.  17    is generated. 
     Long-range light module  4  has light source  7  and optical element  10 . Light source  7  is arranged tilted about an axis of rotation running perpendicular to the optical axis A. In the present exemplary embodiment, the axis of rotation runs in the horizontal direction. Light source  7  is arranged inclined forward by an acute angle φ, so that a main axis H 2  of light source  7  in the region of optical element  10  runs vertically below the optical axis A. 
     In addition, light source  7  is arranged in the plane running perpendicular to the optical axis A and rotated at an angle α, for example, by 15°, which images the angle of cut-off line  32  in light distribution L 2  generated by long-range light module  4  according to  FIG.  18   . Cut-off line  32  is created by imaging an edge  22  of light source  7 . 
     Optical element  10  has a central lens section  23  and a reflection section  24  adjoining lens section  23  transversely to the optical axis A. In lens section  23 , optical element  10  has a first coupling-in surface  25  and a first coupling-out surface  26 . First coupling-in surface  25  is planar and first coupling-out surface  26  is formed convex. Further, optical element  10  comprises a second coupling-in surface  27  and a second coupling-out surface  28  in the region of reflection section  24 . Second coupling-in surface  27  is part of an indentation  29  of optical element  10 . In contrast to optical element  9  of high beam module  3 , optical element  10  is formed cut off on an upper side when viewed vertically. An upper part of a reflection surface  30  is formed smaller than a lower part  30 ′ of the reflection surface. The tilt angle α reproduces the slope of cut-off line  32  in light distribution L 2  according to  FIG.  18   . 
     Light source  7  is arranged oriented to the lower part  30 ′ of reflection surface  30 , so that by means of lower part  30 ′ of reflection surface  30  a main part of the light component totally reflected within optical element  10  is guided to second coupling-out surface  28  of optical element  10 . 
     Second coupling-out surface  28  of optical element  10  can be formed planar, arcuate, or as a free-form surface. 
     In an upper region of optical element  9 , the latter has a recess  31 . Recess  31  is arranged on a left and/or right side, as viewed in the main emission direction H, and causes a cutoff-line  32  of light distribution L 2  to be sharp. Recess  31  ensures that light components are not reflected, which would otherwise lead to flocking  33  (shown as a dashed line in  FIG.  18   ) of the cut-off line  32  with undesired light components. 
     As can be seen in  FIG.  18   , long-range light distribution L 2  runs substantially below a horizontal line. 
     Like long-range light module  4 , forefield light module  5  has a light source  8  which is formed tilted by an angle β with respect to an axis of rotation that runs perpendicular to the optical axis A. A main axis H 3  of light source  8  is tilted upward in the vertical direction, so that the main axis H 3  runs exclusively in the region of optical element  11  above the optical axis A. 
     Optical element  11  of forefield light module  5  has a first coupling-in surface  34  and a first coupling-out surface  35  of a lens section  36  in the central region. Further, optical element  11  comprises, in an outer region, a second coupling-in surface  37  and a second coupling-out surface  38  of a reflection section  29 . 
     Lens section  36  and reflection section  39  are not formed rotationally symmetric. They are formed extended in one direction, namely, preferably in the horizontal direction. First coupling-in surface  34  and first coupling-out surface  35  of lens section  36  thus run in an oval shape in a plane perpendicular to the optical axis A. 
     Second coupling-in surface  37  of optical element  11 , as in the preceding optical elements, is a lateral surface of an indentation  40 . Reflection section  39  has a reflection surface  41  whose upper part  41 ′ has a different parabolic shape than a lower part  41 ″ of reflection surface  41 . The upper part of reflection surface  41  extends above the optical axis A. The lower part of reflection surface  41 ″ extends below the optical axis A. The upper part  41  and the lower part  41 ″ of reflection surface  41  are preferably each formed parabolic in shape. 
     In the upper region of optical element  11 , a recess  42  is provided at a lateral edge, in the area of which no total reflection can occur at reflection surface  41 . This has the effect that optical element  11  produces a sharp cut-off line  43  without undesirable softening or flocking  44  of light distribution L 3  by light components of lower illuminance that form above cut-off line  43  (dashed line in  FIG.  19   ). Like recess  31  of long-range light module  4 , recess  42  of forefield light module  5  is located above the optical axis A. Edge  22  of light source  8  is imaged to cut-off line  43  of light distribution L 2 . 
     An overall depth  45  of optical element  11  is smaller than an overall depth  46  of optical element  9  of long-range light module  3  and an overall depth  47  of optical element  10  of long-range light module  4 . 
     As can be seen in  FIG.  19   , light distribution L 3  of forefield light module  5  runs substantially symmetrically and below a horizontal zero line with a relatively wide dispersion for illuminating a forefield of the vehicle. 
     It should be noted that first coupling-out surface  25 ,  34  of optical element  10  and/or  11  can be formed aspherical. 
     First coupling-out surface  17  of optical element  9  is preferably made anamorphic with aspherical surfaces that differ from one another in the horizontal and vertical directions. 
     To generate a low beam distribution AL according to  FIG.  20    with a cut-off line, light source  7  of long-range module  4  and light source  8  of forefield light module  5  are turned on, so that light distributions L 2  and L 3  are superimposed to form the low beam distribution according to  FIG.  20   . 
     If light source  6  of high beam module  3  is also turned on, a high beam distribution can be generated. 
     Light sources  6 ,  7 ,  8  are preferably formed as LED light sources. 
     Optical elements  8 ,  10 ,  11  are preferably formed from a polycarbonate (PC) or a polymethyl methacrylate (PMA) or silicone. 
     Second coupling-out surface  19 ,  28 ,  38  of optical element  9 ,  10 ,  11  can be provided on the surface with micro-optical elements and cylindrical surface sections. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.