Abstract:
Vehicle headlight comprising a monolithic body of transparent material, the monolithic body including at least one light entry face, a light passage section and at least one optically operative light exit face. The Vehicle headlight further comprises a light source for irradiating light into the light entry face.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the U.S. national phase of PCT/EP2011/005702 filed Nov. 11, 2011. PCT/EP2011/005702 claims the benefit under the Convention of German Patent Application Nos. 10 2010 053 185.5, 10 2011 009 950.6, and 10 2011 107 058.7 filed Dec. 3, 2010, Feb. 1, 2011, and Jul. 11, 2011 (respectively). 
     FIELD OF THE INVENTION 
     The invention relates to a vehicle headlight, in particular to a motor vehicle headlight, including a headlight lens which comprises a monolithic body of transparent material including at least one light entry face and at least one optically operative (also to be understood as ‘effective’) light exit face. 
     BACKGROUND INFORMATION 
     DE 203 20 546 U1 discloses a lens blank-molded on both sides and having a curved surface, a planar surface and a retention edge integrally molded onto the lens&#39; edge, wherein a supporting edge of a thickness of at least 0.2 mm and projecting with respect to the planar surface is integrally formed onto the retention edge. Herein, the supporting edge is integrally formed onto the outer circumference of the headlight lens. A further headlight lens having a supporting edge is disclosed e.g. by DE 10 2004 048 500 A1. 
     DE 20 2004 005 936 U1 discloses a lens for illuminating purposes, notably a lens for a headlight for imaging light emitted from a light source and reflected by a reflector for generating a predetermined illumination pattern, said lens including two opposing surfaces, wherein areas of different optical dispersion effects are provided on at least a first surface. 
     DE 103 15 131 A1 discloses a headlight for vehicles including at least one extensive luminous field including a plurality of illuminating element (diode)-chips and an optical element arranged in the light path of the light beam emitted by the luminous field, wherein the illuminating element chips of the luminous field are arranged in a common recess, and that the recess, on a side facing the direction of light emission, has an outer edge which, in relation to the elimination element chips, is spatially arranged such that a predetermined gradient of light density is formed in a light dispersion of the headlight in the area of the outer edges. 
     DE 10 2004 043 706 A1 discloses an optical system for a motor vehicle headlight for dispersing a beam of light rays from an illuminant, with an optical primary element having an optical face including a break or discontinuity extending along a line, being provided, wherein the optical face is formed to be smooth at least on one side adjacent the discontinuity so that the beam of light rays is separated into two partial beams of light rays. Herein, it is provided that at least one of the partial beams of light rays has a sharp edge of limitation. Moreover, the optical system comprises an optical secondary element for mapping the sharp edge of limitation on to a predetermined light-dark-boundary. 
     EP 1 357 333 A2 discloses a light source device for a vehicle light which has an element emitting semiconductor light, which element is arranged on an optical axis of the light source device and emits its light essentially in an orthogonal direction with regard to the optical axis. 
     Further illumination facilities in context with vehicles are disclosed by DE 42 09 957 A1, DE 41 21 673 A1, DE 43 20 554 A1, DE 195 26 512 A1, DE 10 2009 008 631 A1, U.S. Pat. Nos. 5,257,168 and 5,697,690. 
     It is, in particular, an object of the invention to suggest an improved headlight lens for a vehicle headlight, in particular for a motor vehicle headlight. It is a further object of the invention to reduce the costs for manufacturing vehicle headlights. 
     SUMMARY 
     The aforementioned object is achieved by a vehicle headlight, in particular motor vehicle headlight, including at least one first light source and a headlight lens which comprises a particularly blank-molded monolithic (solid) body of transparent material, wherein the monolithic body comprises at least one light tunnel and one light passage section (light conductive section) including at least one optically operative light exit (sur)face, wherein the light tunnel comprises at least one in particular optically operative (first) light entry (sur)face and, via a bend, passes over (transits) into the light passage section for imaging the bend as a light-dark-boundary (bright-dark-boundary) by means of light from the first light source made to enter or irradiated, respectively, into the (first) light entry face. 
     An optically operative (also termed ‘effective’) light entry face or an optically operative (also ‘effective’) light exit face are (constituted by) an optically operative surface of the monolithic body. In the sense of the invention, an optically operative surface is, in particular, a surface of the transparent body, at which surface, when using the headlight lens according to its purpose light will be refracted. In the sense of the invention an optically operative surface is in particular a surface at which, when using the headlight lens according to its purpose, the direction of light which passes through this surface will be changed. 
     In the sense of the invention, transparent material is particularly glass. In the sense of the invention, transparent material is particularly inorganic glass. In the sense of the invention, transparent material is particularly silicate glass. In the sense of the invention, transparent material is particularly glass as described in document PCT/EP2008/010136. In the sense of the invention, glass particularly comprises
         0.2 to 2% by weight Al 2 O 3 ,   0.1 to 1% by weight Li 2 O,   0.3 (in particular 0.4) to 1.5% by weight Sb 2 O 3 ,   60 to 75% by weight SiO 2 ,   3 to 12% by weight Na 2 O,   3 to 12% by weight K 2 O, and   3 to 12% by weight CaO.       

     In the sense of the invention, the term blank-molding is, in particular, to be understood in a manner that an optically operative surface is to be molded under pressure such that any subsequent finishing or post-treatment of the contour of this optically operative surface may be dispensed with or does not apply or will not have to be provided for, respectively. Consequently, it is particularly provided for that, after blank-molding, a blank-molded surface is not ground, i.e. it need not be treated by grinding. 
     In the sense of the invention a light tunnel is in particular characterized in that, taken essentially, total reflection occurs at its lateral (in particular upper, lower, right and or left) surfaces, so that light entering the light entry face is guided through the tunnel as a light guide. In the sense of the invention a light tunnel is in particular a light guide or light conductor. In particular, it is provided for that total reflection is to occur on the longitudinal surfaces of the light tunnel. In particular, it is provided for that the longitudinal surfaces of the light tunnel are adapted for total reflection. In particular, it is provided for that total reflection is to occur at the surfaces of the light tunnel essentially oriented in the direction of the optical axis of the light tunnel. In particular, it is provided for that the surfaces of the light tunnel essentially oriented in the direction of the optical axis of the light tunnel are adapted for total reflection. A light tunnel, in the sense of the invention, in particular tapers in the direction of its light entry face. A light tunnel, in the sense of the invention, in particular tapers in the direction towards its light entry face by at least 3°. A light tunnel, in the sense of the invention, in particular tapers in the direction towards its light entry face by at least 3° with respect to its optical axis. A light tunnel, in the sense of the invention, in particular tapers at least partially in the direction towards its light entry face. A light tunnel, in the sense of the invention, in particular tapers at least partially in the direction towards its light entry face by at least 3°. A light tunnel, in the sense of the invention, in particular tapers at least partially in the direction towards its light entry face by at least 3° with respect to its optical axis. 
     A bend, in the sense of the invention, is, in particular, a curved transition. A bend, in the sense of the invention, is, in particular, a curved transition having a radius of curvature of no less than 50 nm. It is, in particular, provided for that the surface of the headlight lens has no break or discontinuity in the bend, but is rather in the shape of a curve or curvature. It is, in particular, provided for that the surface of the headlight lens in the bend has a curvature, in particular with a radius of curvature of the curve in the bend of no less than 50 nm. In an embodiment the radius of curvature is no larger than 5 mm. In an expedient embodiment the radius of curvature is no more than 0.25 mm, in particular no more than 0.15 mm, in particular no more than 0.1 mm. In another embodiment of the invention, the radius of curvature of the curve in the bend is at least 0.05 mm. It is, in particular, provided for that the surface of the headlight lens is blank-molded in the region of the bend. 
     In another embodiment of the invention the (first) light source and the (first) light entry face are configured and associated with each other such that light of the (first) light source enters the (first) light entry face at a luminous flux density of at least 75 lm/mm 2 . 
     In another embodiment of the invention the light tunnel is arranged between the bend and the light entry face. In another embodiment of the invention the light passage section is arranged between the bend and the light exit face. In particular, it is provided for that light, which enters the transparent body through the light entry face and enters the passage section from the light tunnel in the area of the bend will exit from the light exit face at an angle of between −20° and 20° with regard to the optical axis. In particular, it is provided for that light which enters the transparent body through the light entry face will exit from the light exit face at an angle of between −20° and 20° with regard to the optical axis. In particular, it is provided for that light which enters the transparent body through the light entry face and enters the passage section from the light tunnel in the area of the bend, will exit from the light exit face essentially in parallel to the optical axis. It is, in particular, provided for that light, which enters the transparent body through the light entry face will exit from the light exit face essentially in parallel to the optical axis. 
     In another embodiment of the invention the bend includes an opening angle of at least 90°. In a further expedient embodiment of the invention the bend includes an opening angle of no more than 150°. In a further favourable embodiment of the invention the bend is arranged on a surface of the light passage section, which surface is facing the light entry face. 
     In another embodiment of the invention the orthogonal of the light entry face is inclined with respect to the optical axis of the light passage section. In a further expedient embodiment of the invention the light entry face is inclined with respect to the optical axis of the light passage section at an angle of between 5° and 70°, in particular at an angle of between 20° and 50°. 
     In another embodiment of the invention the light tunnel comprises a region on its surface which corresponds essentially to a part of the surface of an ellipsoid. In a further expedient embodiment of the invention the light tunnel comprises a region on its surface which corresponds essentially to at least 15% of the surface of an ellipsoid. 
     In another embodiment of the invention the light tunnel comprises a region on its surface, for which the following applies: 
               0   ,     75   ·   a   ·       1   -       y   2       b   2       -       z   2       c   2               ≤   x   ≤     1   ,     25   ·   a   ·       1   -       y   2       b   2       -       z   2       c   2                                       0   ,     75   ·   b   ·       1   -       x   2       a   2       -       z   2       c   2               ≤   y   ≤     1   ,     25   ·   b   ·       1   -       x   2       a   2       -       z   2       c   2                         ,         
in which
     z is a coordinate in the direction (of the optical axis) of the light tunnel;   x is a coordinate orthogonal to the direction of the optical axis of the light tunnel;   y is a coordinate orthogonal to the direction of the optical axis of the light tunnel;   a is a number having a value greater than 0;   b is a number having a value greater than 0; and   c is a number having a value greater than 0.   

     In another embodiment of the invention a surface of the light passage section facing the light tunnel is curved at least in the region of the bend to the transition into the light tunnel, the curvature being, in particular, convex. In another embodiment of the invention the bend is curved in its longitudinal extension. In another embodiment of the invention the bend is curved, in its longitudinal extension, having a radius of curvature of between 5 mm and 100 mm. In another embodiment of the invention the bend is curved, in its longitudinal extension, according to a Petzval curvature (also termed Petzval surface). 
     In a further expedient embodiment of the invention the bend comprises, in its longitudinal extension, a curvature having a radius of curvature in the orientation of the optical axis of the light tunnel and/or of the light passage section. In a yet further embodiment of the invention the radius of curvature is orientated opposite to the light exit face. 
     In another embodiment of the invention the bend is curved in a first direction and in a second direction. In a further expedient embodiment of the invention the first direction is orthogonal to the second direction. In another embodiment of the invention the bend is curved with a first radius of curvature in a first direction and with a second radius of curvature in a second direction, wherein the second radius of curvature is positioned orthogonal to the first radius of curvature. 
     In another embodiment a portion of the surface of the passage section facing the light tunnel is configured as a Petzval surface. In another embodiment of the invention the surface of the light passage section facing the light tunnel is, in a region in which it forms a transition into the light tunnel, configured as a Petzval surface. 
     In another embodiment of the invention the length of the headlight lens, when viewed in the orientation of the optical axis of the light tunnel and/or the light passage section, amounts to no more than 7 cm. 
     In another embodiment of the invention the headlight lens or the transparent body, respectively, has a further light exit face as well as a further light entry face. In a further expedient embodiment of the invention at least 20% of the light entering the light entry face and exiting through the light exit face will exit through the light exit face after having exited from the monolithic body through the further light exit face and having entered the monolithic body through the further light entry face. In another embodiment of the invention at least 10%, in particular at least 20% of the light entering the light entry face and exiting through the light exit face will exit through the light exit face without having exited from the monolithic body through the further light exit face and without having entered the monolithic body through the further light entry face. In a yet further expedient embodiment of the invention at least 75% of the light entering the light entry face and exiting through the light exit face will exit through the light exit face after having exited from the monolithic body through the further light exit face and having entered the monolithic body through the further light entry face. In another embodiment of the invention it is provided for that light which enters the transparent body through the light entry face and enters the passage section from the light tunnel in the region of the bend will either exit from the monolithic body from the further light exit face and enter the further light entry face of the monolithic body as well as it will exit from the monolithic body from the light exit face, or it will exit directly from the light exit face (without exiting from the monolithic body through the further light exit face and entering the further light entry face of the monolithic body). 
     In a further expedient embodiment of the invention the vehicle headlight has no secondary optic associated with the headlight lens. A secondary optic, in the sense of the invention, is in particular an optic for aligning light which exits from the light exit face or from the last light exit face, respectively. A secondary optic, in the sense of the invention, is in particular an optical element for aligning light separated from and/or subordinated with regard to the headlight lens. A secondary optic, in the sense of the invention, is in particular no cover or protection disc, respectively, but an optical element provided for aligning light. An example of a secondary optic is e.g. a secondary lens as has been disclosed in DE 10 2004 043 706 A1. 
     In particular, there is provided that the bend which is imaged as light-dark-boundary lies in the lower region of the light tunnel. 
     In another embodiment of the invention the distance of the light source from the centre of the light exit face, when seen in the orientation of the optical axis of the light tunnel and/or the light passage section amounts to no more than 10 cm. In another embodiment of the invention the length of the vehicle headlight, when seen in the orientation of the optical axis of the light tunnel and/or the light passage section amounts to no more than 10 cm. 
     In a further expedient embodiment of the invention the vehicle headlight comprises at least one second light source spatially separated from the first light source, for making enter or irradiating, respectively, light into the light tunnel and/or immediately/directly (i.e. in particular without passing through the light tunnel) into the light passage section. It may be provided for that, in the sense of the invention, a second light source comprises several partial light sources. In another embodiment of the invention the vehicle headlight comprises at least one second light source spatially separated from the first light source, for making light enter a surface of the light passage section facing the light tunnel. In a further expedient embodiment of the invention light is irradiated, by means of the second light source, above and/or below the light-dark-boundary. 
     In another embodiment of the invention the second light source includes a source for light for driving round corners (such light, in the following briefly termed “corner light”), which corner light source is arranged in particularly to the left of the optical axis of the light tunnel and/or above the optical axis of the light tunnel and/or of the light tunnel (as such). In another embodiment of the invention the corner light source is arranged between the (first) light entry face and the light passage section. In a further embodiment of the invention the second light source includes one, in particular one further corner light source, which, in particular, is arranged to the right of the optical axis of the light tunnel and/or above the optical axis of the light tunnel and/or of the light tunnel (as such). In another embodiment of the invention the corner light source is arranged between the (first) light entry face and the light passage section. 
     In another embodiment of the invention the second light source comprises at least one partial light source arranged above the light tunnel. In another embodiment of the invention the second light source comprises at least two partial light sources arranged above the light tunnel, particularly separated spatially from one another. In another embodiment of the invention the second light source comprises at least one partial light source arranged below the light tunnel. In another embodiment of the invention the second light source comprises at least two partial light sources arranged below the light tunnel, particularly separated spatially from one another. In another embodiment of the invention the partial light source or one or several of the light sources is/are arranged between the (first) light entry face and the light passage portion. 
     In an embodiment of the invention the first light source, a corner light source and/or a partial light source include/s at least one LED or an array of LEDs. In an expedient embodiment of the invention the light source comprises at least one OLED or an array of OLEDs. For example, the light source may well be a plane luminous field. The light source may also include light element chips as have been disclosed by DE 103 15 131 A1. A light source may also be a laser. A suitable laser has been disclosed in ISAL 2011 Proceedings, page 271ff. 
     The aforementioned object is moreover achieved by a vehicle headlight—comprising, in particular, one or several of the aforementioned features—, in particular a motor vehicle headlight, wherein the vehicle headlight includes a headlight lens—comprising, in particular, one or several of the aforementioned features—, wherein the headlight lens includes an in particular blank-molded monolithic body of transparent material including an optically operative first light entry face for making light enter a first light tunnel section; at least one, in particular optically operative second light entry face for making light enter a second light tunnel section; and at least one optically operative light exit face, wherein the monolithic body comprises a light tunnel in (to) which the first light tunnel section and the second light tunnel section open out, wherein the light tunnel, via a bend, passes over (transits) into a light passage section for imaging the bend as a bright-dark-boundary, and wherein the vehicle headlight comprises a first light source for making light enter the first light entry face and a second light source for making light enter the second light entry face. 
     It may be provided for that a light entry face, in the sense of the invention, and/or a light exit face, in the sense of the invention, includes a light dispersing structure. A light dispersing structure, in the sense of the invention, may, for example, be a structure as has been disclosed in DE 10 2005 009 556 A1 and in EP 1 514 148 A1 or EP 1 514 148 B1, respectively. It may be provided for that a light tunnel, in the sense of the invention, is coated. It may be provided for that a light tunnel, in the sense of the invention, is coated with a reflective coating or layer. It may be provided for that, in the sense of the invention, a mirror-like reflective coating is applied to a light tunnel. 
     In the sense of the invention, a motor vehicle is, in particular, a land vehicle for individual use in road traffic. In the sense of the invention, motor vehicles are, in particular, not restricted to land vehicles including a combustion engine. 
     Further advantages and details may be taken from the following description of the examples of embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an example of an embodiment of a motor vehicle; 
         FIG. 2  shows an example of an embodiment of a headlight lens for use in the motor vehicle according to  FIG. 1 ; 
         FIG. 3  shows a cut-out representation of a headlight lens of the motor vehicle headlight lens according to  FIG. 2  by way of a perspective view from below; 
         FIG. 4  shows an enlarged representation of a cut-out cross section of a bend for the transition of a light tunnel into a passage section of a headlight lens according to  FIG. 3 ; 
         FIG. 5  shows a cut-out representation of a headlight lens according to  FIG. 3  by way of a side view; 
         FIG. 6  shows a cut-out representation of a light tunnel of the headlight lens of  FIG. 3  by way of a side view; 
         FIG. 7  shows an example of embodiment regarding an ellipsoid; 
         FIG. 8  shows the ellipsoid according to  FIG. 7  with superimposed representation of a portion of the light tunnel represented in  FIG. 6  by way of a cross sectional representation; 
         FIG. 9  shows a side view of an alternative example of embodiment of a motor vehicle headlight (for use in the motor vehicle according to  FIG. 1 ); 
         FIG. 10  shows a side view of a further alternative example of embodiment of a motor vehicle headlight (for use in the motor vehicle according to  FIG. 1 ); 
         FIG. 11  shows an example of embodiment of a headlight lens of the motor vehicle headlight according to  FIG. 10  by way of a top view; 
         FIG. 12  shows the headlight lens according to  FIG. 11  by way of a rear view; 
         FIG. 13  shows a light-dark-boundary generated by means of the motor vehicle headlight according to  FIG. 10 ; 
         FIG. 14  shows a side view of a further alternative example of embodiment of a motor vehicle headlight (for use in the motor vehicle according to  FIG. 1 ); 
         FIG. 15  shows the motor vehicle headlight according to  FIG. 14  by way of a top view; 
         FIG. 16  shows an example of embodiment of the headlight lens of the motor vehicle headlight according to  FIG. 14  by way of a rear view; 
         FIG. 17  shows a principle representation of an example of embodiment regarding the superimposition of two ellipsoids; 
         FIG. 18  shows a side view of a further example of embodiment of a motor vehicle headlight for use in the motor vehicle according to  FIG. 1 ; 
         FIG. 19  shows the motor vehicle headlight according to  FIG. 18  by way of a top view; 
         FIG. 20  shows a side view of a further example of an embodiment of a motor vehicle headlight for use in the motor vehicle according to  FIG. 1 ; 
         FIG. 21  shows a cut-out side elevation of a further example of embodiment of a motor vehicle headlight for use in the motor vehicle according to  FIG. 1 ; 
         FIG. 22  shows a side elevation of a further example of embodiment of a motor vehicle headlight for use in the motor vehicle according to  FIG. 1 ; 
         FIG. 23  shows a view from the rear of the motor vehicle headlight according to  FIG. 22 ; 
         FIG. 24  shows a top view of a further example of embodiment of a motor vehicle headlight for use in the motor vehicle according to  FIG. 1 ; 
         FIG. 25  shows a light-dark-boundary generated by means of the motor vehicle headlight according to  FIG. 24 ; 
         FIG. 26  shows a further example of an embodiment of a motor vehicle; 
         FIG. 27  shows a further example of an embodiment of a motor vehicle; 
         FIG. 28  shows a light distribution, which, for example, may be achieved with the motor vehicle headlights mentioned before; and 
         FIG. 29  shows a further light distribution, which, for example, may be achieved with the motor vehicle headlights mentioned before. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows an example of embodiment of a motor vehicle  1  including a motor vehicle headlight  10 .  FIG. 2  shows a side view of the motor vehicle headlight  10  including a headlight lens  100 , but without a housing, fittings and energy supply, with the headlight lens  100  being represented in  FIG. 3  in a cut-out manner by way of a perspective bottom view (view from below). The headlight lens  100  comprises a blank-molded monolithic body of inorganic glass, in particular glass, which comprises
         0.2 to 2% by weight Al 2 O 3 ,   0.1 to 1% by weight Li 2 O,   0.3 (in particular 0.4) to 1.5% by weight Sb 2 O 3 ,   60 to 75% by weight SiO 2 ,   3 to 12% by weight Na 2 O,   3 to 12% by weight K 2 O, and   3 to 12% by weight CaO.       

     The blank-molded monolithic body comprises a light tunnel  108 , which, on its one side, has a light entry face  101  and, on another side, passes over into a light passage (or conductive) section  109  (of the blank-molded monolithic body) via a bend  107  curved in two spatial directions, which section  109  includes a light exit face  102 , a light entry face  103  as well as a further light exit face  104 . The headlight lens  100  is configured such that light entering the headlight lens  100  through the light entry face  101  and, in the region of the bend  107 , entering the passage section from the light tunnel  108  will exit from the light exit face  104  essentially in parallel to the optical axis  120  of the headlight lens  100 . In this context, the light passage section  109  images the bend  107  as a light (or bright)/dark-boundary. A portion of the surface of the light passage section  109  facing the light tunnel  108  is configured as a Petzval surface, said surface portion having been designated by reference numeral  110 . 
     The motor vehicle headlight  10  includes a light source  11  configured as an LED and a light source  12  configured as an LED. For the purpose of implementing a dipped-beam headlights, light is irradiated into or made to enter (coupled into), respectively, the light entry face  101  of the light tunnel  108  by means of the light source  11 . By means of the light source  12 , which may be switched-on alternatively for implementing a sign light or a high-beam headlight, light is introduced (made to enter or coupled into) or irradiated, respectively, into a bottom side of the light tunnel  108  or into the portion  110 , respectively, of the surface of the light passage section  109  facing the light tunnel  108 , which portion  110  is configured as a Petzval surface. 
       FIG. 4  shows, by way of an enlarged representation, a cut-out of the bend  107  for a passing over (transiting) of the light tunnel  108  into the light passage section  109 , the bend  107  being formed by blank-molding and configured as a continuous, curved transition. 
       FIG. 5  shows a cut-out representation of a side view of the headlight lens  100 .  FIG. 6  shows an enlarged cut-out representation of a part of the light tunnel  108  up to the dotted line in  FIG. 5  designated by reference numeral  111 . The upper portion of the part of the light tunnel as shown in  FIG. 6  has been configured as an ellipsoid  150  as represented in  FIG. 7 . Herein, the dotted line  111  approximately corresponds to the axis C-D. For clarifying this embodiment, a part of the cross section of the light tunnel  108  in  FIG. 8  is shown in a manner superimposing (overlaying) the representation of the ellipsoid  150 . For the ellipsoid  150  represented in  FIG. 7  the following applies: 
     
       
         
           
             
               
                 
                   x 
                   2 
                 
                 
                   a 
                   2 
                 
               
               + 
               
                 
                   y 
                   2 
                 
                 
                   b 
                   2 
                 
               
               + 
               
                 
                   z 
                   2 
                 
                 
                   c 
                   2 
                 
               
               - 
               1 
             
             = 
             0 
           
         
       
     
     Herein, there is
     z a coordinate in the direction of the optical axis of the light tunnel (A→B);   x a coordinate orthogonal to the direction of the optical axis of the light tunnel; and   y a coordinate orthogonal to the direction of the optical axis of the light tunnel and to the x-direction (D→C).   

     a, b and, consequently, c have been chosen such that all light beams or rays which pass through focus F 1  will concentrate again in focus F 2  after mirroring in the surface of the ellipsoid. The course of the beams of light from the light source  11 , which is irradiated into or made to enter (coupled into) the light entry face  101 , respectively, is clearly illustrated by the light beams  121  and  122  depicted in  FIG. 6 . Reference numeral  120  of  FIG. 6  designates the orthogonal of the light entry face  101 . The mutual point of intersection of the orthogonal  120  of the light entry face  101  with the light beams  121  and  122  has been designated by reference numeral  115 . The position of this point of intersection  115  corresponds to focus F 1  in  FIG. 7  and  FIG. 8 . 
       FIG. 9  shows a side elevation of a motor vehicle headlight  20  to be used alternatively with regard to motor vehicle headlight  10 . The motor vehicle headlight  20  comprises a headlight lens  200 . The headlight lens  200  comprises a blank-molded monolithic body of inorganic glass including a light tunnel  208 , which has a light exit face  201  on one side and, on the other side, passes over/transits into a light passage or conductive section  209  (of the blank-molded monolithic body) via a bend  207  curved in the three spatial dimensions, which light passage section  209  includes a light exit face  202 , a light entry face  203 , as well as a further light exit face  204 . The headlight lens  200  is shaped such that light which enters the headlight lens  200  through the light entry face  201  and from the light tunnel  208  enters the passage section in the region of the bend  207 , will exit from the light exit face  204  essentially in parallel to the optical axis of the headlight lens  200 . Herein, the light passage section  209  images the bend  207  as a light-dark-boundary. A portion of the surface of the light passage section  209  designated by reference numeral  210  and facing the light tunnel  208  is shaped as a Petzval surface. 
     The motor vehicle headlight  20  includes a light source  21  configured as an LED, and a light source  22  configured as an LED. By means of light source  21 , and for the purpose of implementing a dipped-beam headlight, light is irradiated into or made to enter (coupled into), respectively, the light entry face  201  of the light tunnel  208 . By means of the selectively connectable light source  22 , and for implementing sign light or high-beam headlight, light is made to enter or is irradiated, respectively, into a bottom side of the light tunnel  208  or the Petzval-face-configured portion  210 , respectively, of the surface of the light passage section  209  facing the light tunnel  208 . 
       FIG. 10  shows a side elevation of a further motor vehicle headlight  30  to be used alternatively with regard to motor vehicle headlight  10 . The further motor vehicle headlight  30  comprises a headlight lens  300 .  FIG. 11  shows the headlight lens  300  by way of a top view, and  FIG. 12  shows the headlight lens  300  from the rear. The headlight lens  300  comprises a blank-molded monolithic body of inorganic glass, which body comprises a light tunnel  308 , which has a light entry face  301  on one side and, on the other side, passes over (transits) into a light passage or conductive section  309  (of the blank-molded monolithic body) via a bend  207  curved in two spatial dimensions, which light passage section  209  includes a light exit face  302 . The headlight lens  300  is configured such that light which enters the headlight lens  300  through the light entry face  301  and, from the light tunnel  308  enters the passage section in the region of the bend  307  will exit from the light exit face  302  essentially in parallel to the optical axis of the headlight lens  300 . Herein, the light passage section  309  images the bend  307  as a light-dark-boundary, as has been depicted in  FIG. 13 . A portion of the surface of the light passage section  309  designated by reference numeral  310  and facing the light tunnel  308  is configured as a Petzval surface. A rim or edge, in particular a circumferential edge, may be arranged on the section designated by reference numeral  330 , of the surface of the passage section  309 , by means of which section  330  the headlight lens  300  may be fixed in a particularly appropriate manner. 
     The motor vehicle headlight  30  includes a light source  31  configured as an LED, and a light source  32  configured as an LED. By means of the light source  31 , and for the purpose of implementing a dipped-beam headlight, light is irradiated into or made to enter, respectively, the light entry face  301  of the light tunnel  308 . By means of the selectively connectable light source  32  for implementing sign light or high-beam headlight, light is made to enter or is irradiated, respectively, into a bottom side of the light tunnel  208  or into the Petzval-surface-configured portion  310  of the surface of the light passage section  309  facing the light tunnel  308 , respectively. 
       FIG. 14  shows a further motor vehicle headlight  40  by way of a side elevation and to be used alternatively with regard to motor vehicle headlight  10 . The motor vehicle headlight  40  comprises a headlight lens  400 .  FIG. 15  shows the motor vehicle headlight  40  by way of a top view, and  FIG. 16  shows the headlight lens  400  from the rear. The headlight lens  400  comprises a blank-molded monolithic body of inorganic glass, which body comprises a light tunnel section  408 A and a light tunnel section  408 B, which open out in a light tunnel  408  which, in turn, passes over (transits) to a light passage section  409  (of the blank-molded monolithic body) via a bend  407  curved in two spatial directions, which section  409  includes a light exit face  402 , a light entry face  403 , as well as a further light exit face  404 . The light tunnel section  408 A includes a light entry face  401 A, and the light tunnel section  408 B includes a light entry face  401 B. The headlight lens  400  is shaped such that light, which enters the headlight lens  400  through the light entry faces  401 A and  401 B and, in the region of the bend  407  enters the passage section from the light tunnel  408  will exit from the light exit face  404  essentially parallel to the optical axis of the headlight lens  400 . Herein, the light passage section  409  images the bend  407  as a light-dark-boundary. A portion of the surface of the light passage section  409  designated by reference numeral  410  and facing the light tunnel  408  is shaped as a Petzval surface. 
     At least in their upper region, the light tunnel sections  408 A and  408 B are configured—taken in analogy to the explanations relating to  FIG. 6 —as part of an ellipsoid, as has been represented in principle in  FIG. 17 . Herein, reference numeral  150 A designates an ellipsoid associated with the light tunnel section  408 A, and reference numeral  150 B designates an ellipsoid associated with the light tunnel section  408 B. The ellipsoids  150 A and  150 B are, as has been represented in  FIG. 17 , aligned in relation to each other such that the respective focuses F 2  will lie on top of each other. At the points designated by reference numerals  151 A and  151 B or starting at points  151 A and  150 B (in the direction of light propagation or towards the right, respectively), respectively, the surface contour of the headlight lens  400  deviates from the contour of an ellipsoid. Herein, the angles α A  and α B  indicate the directions of deviation from the elliptic shape. 
     The motor vehicle headlight  40  includes two light sources, which, in analogy to light source  11  have been configured as LEDs and have not been depicted in  FIG. 14  and  FIG. 16  for the sake of clarity. By means of one of the light sources, and for the purpose of implementing a dipped-beam headlight, light is irradiated into or made to enter, respectively, the light entry face  401 A of the light tunnel section  408 A, and by means of the other one of the light sources, and for the purpose of implementing a dipped-beam headlight, light is irradiated into or made to enter, respectively, the light entry face  401 B of the light tunnel section  408 B. In addition, a non-shown the light source may be provided, which corresponds to light source  12  with respect to position and performance. 
     In addition, and for implementing a corner light and/or a front fog light (adverse weather lamp) light sources  45  and  46  configured as LEDs are provided, with the light sources  45  and  46  being adapted to be switched-on or connected alternatively for implementing the corner light. Herein, a non-shown control is provided for within the motor vehicle  4 , by means of which the control light source  45  is connected for the time of driving round a left corner, and light source  46  is switched-on for the time of driving round a right corner. For implementing a front fog light, either light source  46  or both light sources  45  and  46  are switched on. 
       FIG. 18  and  FIG. 19  show a motor vehicle headlight lens  10 A to be used alternatively with regard to motor vehicle headlight  10 . Herein,  FIG. 18  shows a side elevation of the motor vehicle headlight lens  10 A, and  FIG. 19  shows a top view of the motor vehicle headlight lens  10 A. The motor vehicle headlight lens  10 A comprises the headlight lens  100  as well as the light source  11 . In addition, for implementing a corner (or curve) light and/or a front fog light, light sources  15  and  16  configured as LEDs have been provided for. It may as well be provided for that, in addition, the light source  12  is implemented within the motor vehicle headlight  10 A. 
     For implementing a corner light the light sources  15  and  16  may be switched-on alternatively. In this context, a non-shown control is provided for in the motor vehicle  1 , by means of which light source  15  may be switched-on for the time of driving round a left corner and light source  16  may be connected for the time of driving round a right corner. For implementing a front fog light either the light source  16 , only, or both light sources  15  and  16  are switched-on. 
       FIG. 20  shows a motor vehicle headlight  10 B (based on headlight lens  100 ) to be used alternatively with regard to motor vehicle headlight  10  and provided with a light source  18  adapted to be connected (switched-on) and configured as an LED, for a high-beam headlight function, and with a light source  19  configured as LED, for a sign light function, wherein the light output of the light source  18  is higher than that of light source  19 . 
       FIG. 21  shows a further alternative embodiment of a motor vehicle headlight  10 C on the base of headlight lens  100 . Herein, additional light sources  1001 ,  1002 ,  1003 ,  1004 ,  1005 ,  1006  are provided along the light tunnel  108 . By means of this arrangement a higher light output may be achieved. The light sources  1003 ,  1004 ,  1005 ,  1006  or one or several of the light sources  1003 ,  1004 ,  1005 ,  1006  may be provided in context with the motor vehicle headlight  10 B as well. 
       FIG. 22  shows a further alternative of a motor vehicle headlight  10 D based on the headlight lens  100 .  FIG. 23  shows the motor vehicle headlight  10  D from the rear, however, without the light source  11 . Herein, light is made to enter the Petzval-face-configured surface  110  of the passage section  109  by means of an LED array  1010 , whose components may be individually controlled or connected, respectively. 
       FIG. 24  shows a top view of a further example of embodiment of an alternatively applicable motor vehicle headlight  30 A. The motor vehicle headlight  30 A includes partial headlights designated by reference numerals  3001 ,  3002 ,  3003 , and  3004 , which have headlight lenses configured in analogy to headlight lens  300 , each, however, including a circumferential rim or edge  331  with differently configured bends, so that the light-dark-boundary  3005  represented in  FIG. 25  may be generated. It may be provided for that the partial headlights  3001 ,  3002 ,  3003 , and  3004  may have LED arrays corresponding to LED array  1010 . The optical axes of the partial headlights  3001 ,  3002 ,  3003 , and  3004  are slightly inclined with respect to each other so that the partial headlight  3001  illuminates essentially the −8°-region, the partial headlight  3002  illuminates essentially the −4°-region, the partial headlight  3003  illuminates essentially the 4°-region, and the partial headlight  3004  illuminates essentially the 8°-region (cf.  FIG. 25 ). It may be provided for that the partial headlights  3001 ,  3002 ,  3003 , and  3004  be fixedly connected to each other within a module. It may be provided for that the partial headlights  3001 ,  3002 ,  3003 , and  3004  be arranged in a mutual housing. It may also be provided for that the partial headlights  3001 ,  3002 ,  3003 , and  3004  as well as further corresponding partial headlights be arranged along the circumference of a geometrical figure, in particular along a circle. It may be provided for that the partial headlights  3001 ,  3002 ,  3003 , and  3004 , are arranged, as has been represented in  FIG. 26 , within a motor vehicle  1 A.  FIG. 27  shows a further example of embodiment of a motor vehicle  1 B. 
       FIG. 28  and  FIG. 29  show distributions of illumination which, purely by way of example, may be achieved with the aforementioned motor vehicle headlights. Herein, the left area is illuminated by motor vehicle headlights at the positions of partial headlights  3001  and  3002  according to  FIG. 26 , and the right area is illuminated by the motor vehicle headlights at the positions of the partial headlights  3003  and  3004  according to  FIG. 26 . In  FIG. 28  and  FIG. 29 , the following reference characters designate the following (light functions): AB the dipped-beam headlight, HS a hotspot, GBL the basic illumination, SL sign light, NL fog light, KL corner light, and FL high-beam headlight. 
     For example, it has been provided for that dipped-beam headlight, hotspot and basic illumination may be implemented together in connection with a headlight lens (e.g. headlight lens  100  or  200 ) by means of a light source  11  or  21 . It may, however, also be provided for that dipped-beam headlight, hotspot and basic illumination be implemented partially in connection with different headlight lenses (e.g. headlight lens  100  or  200 ) by means of a light source  11  or  21 . It may e.g. be provided for that fog light is implemented in connection with a further headlight lens (e.g. headlight lens  100  or  200 ) by means of a light source  11  or  21 . It is e.g. provided for that sign light is implemented by means of a light source  18  or  19 . It is e.g. provided for that high-beam headlight is implemented by means of a light source  19  or  18 . It is e.g. provided for that corner (or curve) light is implemented by means of a light source  15  or  16 , respectively. The following table shows examples of embodiment for partitioning the areas for the right half (wherein a “+” indicates the illumination of an area): 
     
       
         
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                   
               
               
                   
                 AB + HS 
                 GBL 
                 SL 
                 NL 
                 KL 
                 FL 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Example 1 
                 “Position 3004” 
                 + 
                   
                 + 
                   
                 + 
                   
               
               
                   
                 “Position 3003” 
                   
                 + 
                   
                   
                   
                 + 
               
               
                 Example 2 
                 “Position 3004” 
                 + 
                   
                 + 
                   
                   
                   
               
               
                   
                 “Position 3003” 
                   
                 + 
                   
                   
                 + 
                 + 
               
               
                 Example 3 
                 “Position 3004” 
                 + 
                 + 
                 + 
                   
                 + 
                   
               
               
                   
                 “Position 3003” 
                   
                   
                   
                 + 
                   
                 + 
               
               
                 Example 4 
                 “Position 3004” 
                 + 
                 + 
                   
                   
                 + 
                 + 
               
               
                   
                 “Position 3003” 
                   
                   
                 + 
                 + 
                   
                   
               
               
                 Example 5 
                 “Position 3004” 
                 + 
                 + 
                 + 
                   
                   
                   
               
               
                   
                 “Position 3003” 
                   
                   
                   
                 + 
                 + 
                 + 
               
               
                 Example 6 
                 “Position 3004” 
                 + 
                 + 
                   
                   
                   
                 + 
               
               
                   
                 “Position 3003” 
                   
                   
                 + 
                 + 
                 + 
                   
               
               
                 Example 7 
                 “Position 3004” 
                 + 
                   
                 + 
                 + 
                 + 
                   
               
               
                   
                 “Position 3003” 
                   
                 + 
                   
                   
                   
                 + 
               
               
                 Example 8 
                 “Position 3004” 
                 + 
                   
                 + 
                 + 
                   
                   
               
               
                   
                 “Position 3003” 
                   
                 + 
                   
                   
                 + 
                 + 
               
               
                 Example 9 
                 “Position 3004” 
                 + 
                   
                   
                 + 
                 + 
                 + 
               
               
                   
                 “Position 3003” 
                   
                 + 
                 + 
                   
                   
                   
               
               
                 Example 
                 “Position 3004” 
                 + 
                   
                   
                 + 
                   
                 + 
               
               
                 10 
                 “Position 3003” 
                   
                 + 
                 + 
                   
                 + 
               
               
                   
               
             
          
         
       
     
     The elements, distances and angles in the figures have been drawn in consideration of simplicity and clearness and not necessarily to scale. For example, the orders of magnitude of some elements, distances and angles have been exaggerated with respect to other elements, distances and angles in order to improve comprehension of the example of embodiment of the present invention.