Abstract:
A headlight lens for a vehicle headlight, the headlight lens having a body of transparent material. The monolithic body includes a light passage section having at least one optically operative light exit face and a light tunnel having at least one optically operative light entry face. The light tunnel transits into the light passage section via a bend being curved in its longitudinal extension, wherein the light passage section is configured for imaging the bend as a bright-dark-boundary.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. application Ser. No. 13/990,081, filed May 29, 2013, which is a US National Phase of PCT/EP2011/005698, filed Nov. 11, 2011, which claims benefit under the Convention of German Patent Applications No. 102010053185.5, filed Dec. 3, 2010; No. 102011009950.6, filed Feb. 1, 2011; and No. 102011107056.0, filed Jul. 11, 2011. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a headlight lens for a vehicle headlight, in particular for a motor vehicle headlight, wherein the headlight lens includes a monolithic body of transparent material including at least one optically operative (also termed ‘effective’) light entry face and at least one optically operative (effective) light exit face. 
       BACKGROUND INFORMATION 
       [0003]    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. 
         [0004]    DE 20 2004 005 936 U1 discloses a lens for illuminating purposes, in particular a lens for a headlight for imaging or imaging light emitted from a light source and reflected by a reflector for generating a predetermined illumination pattern, said lens having two surfaces opposing each other, wherein areas of different optical dispersion effects are provided on at least a first surface. 
         [0005]    DE 103 15 131 A1 discloses a headlight for vehicles having 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. 
         [0006]    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 imaging the sharp edge of limitation on to a predetermined bright-dark-boundary. 
         [0007]    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. 
         [0008]    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. No. 5,257,168 and U.S. Pat. No. 5,697,690. 
         [0009]    It is 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 
       [0010]    The aforementioned object is achieved by a headlight lens for a vehicle headlight, in particular for a motor vehicle headlight, wherein the headlight lens includes a monolithic body of transparent material including at least one (in e.g. optically operative) light entry face and at least one optically operative light exit face, wherein the monolithic body comprises a light tunnel which, via a bend, passes (or transits) into a light passage section (of the monolithic body) for imaging the bend as a bright-dark-boundary. 
         [0011]    An optically operative or effective light entry (sur)face or an optically operative or effective light exit (sur)face are (constituted by) an optically operative or effective surface of the monolithic body. An optically operative surface is, in particular, a surface of the transparent body, at which surface light will be refracted, when using the headlight lens according to its purpose. An optically operative surface is, in particular, a surface at which the direction of light which passes through this surface will be changed when using the headlight lens according to its purpose. 
         [0012]    Transparent material is particularly glass. Transparent material is particularly inorganic glass. Transparent material is particularly silicate glass. Transparent material is e.g. glass as described in document PCT/EP2008/010136. Glass e.g. comprises
       0.2 to 2% by weight Al2O3,   0.1 to 1% by weight Li2O,   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.       
 
         [0020]    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. 
         [0021]    A light tunnel is, in particular, characterized in that essentially total reflection takes place at its lateral (in particular top, bottom, right and/or left) surfaces, so that light entering the light entry face is guided through the tunnel as a light conductor or guide. A light tunnel is in particular a light guide. In particular, it is provided for that total reflection is achieved at 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 achieved at the surfaces of the light tunnel essentially oriented in the direction of the optical axis of the light tunnel. A light tunnel, e.g., tapers in the direction of its light entry face. A light tunnel, e.g., tapers in the direction towards its light entry face by at least 3°. A light tunnel, e.g., tapers in the direction towards its light entry face by at least 3° with respect to its optical axis. A light tunnel, e.g., tapers at least partially in the direction towards its light entry face. A light tunnel, e.g., tapers at least partially in the direction towards its light entry face by at least 3°. A light tunnel, e.g., tapers at least partially in the direction towards its light entry face by at least 3° with respect to its optical axis. 
         [0022]    A bend is, in particular, a curved transition. A bend 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 rather 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, e.g., no more than 0.15 mm, e.g., no more than 0.1 mm. In another embodiment the radius of curvature of the curve in the bend is at least 0.05 mm. It is, e.g., provided for that the surface of the headlight lens is blank-molded in the region of the bend. 
         [0023]    In another embodiment the light tunnel is arranged between the bend and the light entry face. In another embodiment the light passage section is arranged between the bend and the light exit face. E.g., it is provided that light, which enters the transparent body through the light entry face and enters the passage section in the area of the bend of the light tunnel will exit from the light exit face at an angle of between −20° and 20° with regard to the optical axis. E.g., 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. E.g., it is provided for that light which enters the transparent body through the light entry face and enters the passage section in the area of the bend of the light tunnel will exit from the light exit face essentially in parallel to the optical axis. It is, e.g., provided for that light, which enters the transparent body from the light entry face will exit from the light exit face essentially in parallel to the optical axis. 
         [0024]    In another embodiment the bend includes an opening angle of at least 90°. In a further expedient embodiment the bend includes an opening angle of no more than 150°. In another embodiment the bend is arranged on the surface of the light passage section, which surface is facing the light entry face. 
         [0025]    In another embodiment 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 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°, e.g., at an angle of between 20° and 50°. 
         [0026]    In another embodiment the light tunnel comprises an area on its surface which corresponds essentially to a part of the surface of an ellipsoid. In a further expedient embodiment the light tunnel comprises an area on its surface which corresponds essentially to at least 15% of the surface of an ellipsoid. 
         [0027]    In another embodiment the light tunnel comprises a region on its surface, for which the following applies: 
         [0000]    
       
         
           
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         [0028]    wherein there is 
         [0029]    z a coordinate in the direction (of the optical axis) of the light tunnel; 
         [0030]    x a coordinate orthogonal to the direction of the optical axis of the light tunnel; 
         [0031]    y a coordinate orthogonal to the direction of the optical axis of the light tunnel; 
         [0032]    a a number having a value exceeding (greater than) 0; 
         [0033]    b a number having a value exceeding (greater than) 0; and 
         [0034]    c a number having a value exceeding (greater than) 0. 
         [0035]    In another embodiment a surface of the light passage section facing the light tunnel is curved at least in the region of the bend into the transition into the light tunnel, the curvature being, e.g., convex. In another embodiment the bend is curved in its longitudinal extension. In another embodiment the bend is curved, in its longitudinal extension, the curvature having a radius of curvature of between 5 mm and 100 mm. In another embodiment the bend is curved, in its longitudinal extension, according to a Petzval curvature (also termed Petzval surface). 
         [0036]    In a further expedient embodiment the bend, in its longitudinal extension, comprises 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 preferred embodiment the radius of curvature is orientated opposite to the light exit face. 
         [0037]    In another embodiment the bend is curved in a first direction and in a second direction. In a further expedient embodiment the first direction is orthogonal to the second direction. In another embodiment 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. 
         [0038]    In another embodiment a portion of the surface of the passage section facing the light tunnel is designed as a Petzval surface. In another embodiment the surface of the light passage section facing the light tunnel is, in a region in which it transits into the light tunnel, designed as a Petzval surface. 
         [0039]    In another embodiment 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. 
         [0040]    In another embodiment the headlight lens or the transparent body has a further light exit face as well as a further light entry face. In a further expedient embodiment 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 into the monolithic body through the further light entry face. In another embodiment at least 10%, e.g., 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 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 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 through 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 further light exit face from the monolithic body and without entering the further light entry face of the monolithic body). 
         [0041]    The aforementioned object is, moreover, achieved by a vehicle headlight, in particular a motor vehicle headlight, wherein the vehicle headlight has a headlight lens includes one or several of the aforementioned features as well as a light source for emitting light into or making it enter the first light entry face. In an embodiment the light source comprises at least one LED or an array of LED&#39;s. In an expedient embodiment the light source comprises at least one OLED or an array of OLED&#39;s. For example the light source may as well be a plane luminous field. The light source may also comprise light element chips as have been disclosed by DE 103 15 131 A1. A light source may also be a laser. A laser to be used has been disclosed in ISAL 2011 Proceedings, page 271ff. 
         [0042]    In a further expedient embodiment the vehicle headlight has no secondary optic associated with the headlight lens. A secondary optic is in particular an optical device for aligning light which exits from the light exit face or from the last light exit face of the headlight lens, respectively. A secondary optic is in particular an optical element for aligning light separated from and/or subordinated with regard to the headlight lens. A secondary optic is, in particular, no cover or protection disc, but an optical element provided for aligning light. As an example for a secondary optic there is disclosed e.g. a secondary lens in DE 10 2004 043 706 A1. 
         [0043]    In particular, there is provided that the bend which is imaged as bright-dark-boundary lies in the lower region of the light tunnel. 
         [0044]    In another embodiment 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 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. 
         [0045]    There may be provided one or several further light sources whose light is made to enter or is irradiated into the passage section and/or a part of the light tunnel for implementing sign light, country or drive light and/or curve light. When making such additional light enter the light tunnel it is, in particular, provided that this occurs in that half of the light tunnel which is closer to the light passage section and/or in which the light entry face is not provided for. 
         [0046]    The aforementioned object is moreover achieved by a headlight lens for a vehicle headlight, in particular for a motor vehicle headlight, the headlight lens comprising one or several of the aforementioned features, wherein the headlight lens includes monolithic body of transparent material and including a first light entry face for making light enter a first light tunnel section; at least a 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 into which the first light tunnel section and the second light tunnel section open out, wherein the light tunnel, via a bend, passes over (or ‘transits’) into a light passage section for imaging the bend as a bright-dark-boundary. 
         [0047]    In another embodiment the orthogonal of the first light entry face is inclined with respect to the optical axis of the light conductive section. In a further expedient embodiment the first light entry face is inclined with respect to the optical axis of the light passage section at an angle of between 5° and 70°, e.g., at an angle of between 20° and 50°. In another embodiment the orthogonal of the second light entry face is inclined with respect to the optical axis of the light passage section. In a further expedient embodiment the second light entry face is inclined with respect to the optical axis of the light passage section at an angle of between 5° and 70°, e.g., at an angle of between 20° and 50°. 
         [0048]    In another embodiment the first light tunnel section in comprises an area on its surface which corresponds essentially to a part of the surface of an ellipsoid. In a further expedient embodiment the first light tunnel section comprises an area on its surface which corresponds essentially to at least 20% of the surface of an ellipsoid. In another embodiment the second light tunnel section comprises an area on its surface corresponding essentially to part of an ellipsoid surface. In a further expedient embodiment the second light tunnel section comprises an area on its surface corresponding essentially to at least 20% of an ellipsoid surface. 
         [0049]    In another embodiment the light tunnel comprises a region on its surface, for which the following applies: 
         [0000]    
       
         
           
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         [0050]    in which 
         [0051]    z is a coordinate in the direction (of the optical axis) of the light tunnel; 
         [0052]    x is a coordinate orthogonal to the direction of the optical axis of the light tunnel; 
         [0053]    y is a coordinate orthogonal to the direction of the optical axis of the light tunnel; 
         [0054]    a is a number having a value greater than 0; 
         [0055]    b is a number having a value greater than 0; and 
         [0056]    c is a number having a value greater than 0. 
         [0057]    The aforementioned object is moreover achieved by a vehicle headlight, in particular a motor vehicle headlight, wherein the vehicle headlight has a headlight lens including one or several of the aforementioned features as well as a first light source for introducing light into the first light entry face and at least a second light source for introducing light into the second light entry face. In an embodiment the first and/or the second light sources include at least one LED or an array of LEDs. In an expedient embodiment the first and/or the second light sources comprise at least one OLED or an array of OLEDs. For example, the first and/or the second light sources may well be a plane luminous field. The first and/or the second light sources may also include light element chips as have been disclosed by DE 103 15 131 A1. 
         [0058]    In a further expedient embodiment the vehicle headlight has no secondary optic associated with the headlight lens. A secondary optic is in particular an optical device for aligning light which exits from the light exit face or from the last light exit face of the headlight lens, respectively. A secondary optic is in particular an optical element for aligning light separated from and/or subordinated with regard to the headlight lens. A secondary optic is, in particular, no cover disc or protection plate, but an optical element provided for aligning light. As an example for a secondary optic there is disclosed e.g. a secondary lens in DE 10 2004 043 706 A1. 
         [0059]    In particular, it is provided that the bend which is imaged as bright-dark-boundary lies in the lower region of the light tunnel. 
         [0060]    In another embodiment the distance of the first and/or of the second light sources 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 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. 
         [0061]    There may be provided one or several further light sources whose light is made to enter or is irradiated into the passage section and/or a part of the light tunnel for implementing sign light, country or drive light and/or curve light. When making such additional light enter the light tunnel there is, in particular, provided that this occurs in that half of the light tunnel which is closer to the light passage section and/or in which the light entry face is not located. 
         [0062]    In another embodiment the light source and the (first) light entry face are designed and associated with each other such that light from the light source enters the light entry face at a luminous flux density of at least 75 lm/mm 2 . 
         [0063]    The aforementioned headlight lenses may be manufactured by means of a process in which the monolithic body is blank-molded between a first partial mold and at least one second partial mold such
       that a first region of the first light entry face is formed by means of the first partial mold and a second region of the first light entry face is molded by means of the second partial mold;   that a first region of the first light exit face is formed by means of the first partial mold and a second region of the first light exit face is formed by means of the second partial mold;   that a first region of the second light entry face is formed by means of the first partial mold and a second region of the second light entry face is formed by means of the second partial mold and/or   that a first region of the second light exit face is formed by means of the first partial mold and a second region of the second light exit face is formed by means of the second partial mold.       
 
         [0068]    In pressing, it is e.g. provided for that the first partial mold and the second partial mold are moved to approach each other. Herein, the first partial mold may be made to approach the second partial mold and/or the second partial mold can be made to approach the first partial mold. 
         [0069]    Alternatively, the aforementioned headlight lenses may be manufactured by means of a common injection molding procedure. Furthermore, the aforementioned optical components or headlight lenses, respectively, may alternatively be manufactured by means of a procedure disclosed in DE 11 2008 003 157, wherein it is, in particular, provided for that a blank of glass is heated such that it assumes a viscosity of between 10 4  Pa*s and 10 5  Pa*s, e.g. of between 10 4  Pa*s and 5·10 4  Pa*s, and wherein—after heating—the blank is molded in an injection mold to form a headlight lens. 
         [0070]    It may be provided for that a light entry face and/or a light exit face has a light scattering structure. A light scattering structure 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. 
         [0071]    In the sense of the invention, a motor vehicle is, in particular, a land vehicle to be used individually in road traffic. In the sense of the invention, motor vehicles are, in particular, not restricted to land vehicles including a combustion engine. 
         [0072]    Further advantages and details may be taken from the following description of the examples of embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0073]      FIG. 1  shows an example of an embodiment of a motor vehicle; 
           [0074]      FIG. 2  shows an example of an embodiment of a headlight lens for use in the motor vehicle according to  FIG. 1 ; 
           [0075]      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; 
           [0076]      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 ; 
           [0077]      FIG. 5  shows a side view of a cut-out representation of a headlight lens according to  FIG. 3 ; 
           [0078]      FIG. 6  shows a side view of a cut-out representation of a light tunnel of headlight lens of  FIG. 3 ; 
           [0079]      FIG. 7  shows an example of embodiment for an ellipsoid; 
           [0080]      FIG. 8  shows a cross sectional representation of the ellipsoid according to  FIG. 7  with a superimposed representation of a portion of the light tunnel represented in  FIG. 6 ; 
           [0081]      FIG. 9  shows a side view of an example of embodiment of a headlight lens for alternative use in the headlight lens according to  FIG. 2 ; 
           [0082]      FIG. 10  shows a side view of a further example of embodiment of a headlight lens for alternative use in the motor vehicle headlight according to  FIG. 2 ; 
           [0083]      FIG. 11  shows a top view of the headlight lens according to  FIG. 10 ; 
           [0084]      FIG. 12  shows a rear view of the headlight lens according to  FIG. 10 ; 
           [0085]      FIG. 13  shows a bright-dark-boundary generated by means of the headlight lens according to  FIG. 10 ; 
           [0086]      FIG. 14  shows a side view of a further example of embodiment of a headlight lens for alternative use in the motor vehicle headlight according to  FIG. 2 ; 
           [0087]      FIG. 15  shows a top view of the headlight lens according to  FIG. 14 ; 
           [0088]      FIG. 16  shows a rear view of the headlight lens according to  FIG. 14 ; 
           [0089]      FIG. 17  shows a principle representation of an example of embodiment for superimposing two ellipsoids; 
           [0090]      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 ; and 
           [0091]      FIG. 19  shows a top view of the motor vehicle headlight according to  FIG. 18 . 
       
    
    
     DETAILED DESCRIPTION 
       [0092]      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  having 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 monolithic body of inorganic glass, in e.g. glass, which comprises
       0.2 to 2% by weight Al 2 O 3 ,   0.1 to 1% by weight Li2O,   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.       
 
         [0100]    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 (or transits) into a light passage (guide or conductive) section  109  (of the blank-molded monolithic body) via a bend  107  curved in two spatial directions, which section  109  has a light exit face  102 , a light entry face  103  as well as a further light exit face  104 . The headlight lens  100  is designed 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 . Herein, the light passage section  109  maps 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 designed as a Petzval surface, said surface portion having been designated by reference numeral  110 . 
         [0101]    The headlight lens  10  includes a light source  11  designed as an LED and a light source  12  designed as an LED. For the purpose of implementing dimmed headlights light is irradiated into or made to enter, respectively, the light entry face  101  of the light tunnel  108  by means of the light source  11 . By means of light source  12 , which may be switched-on selectively for implementing a sign light or a drive/flash light, light is, respectively, introduced or irradiated into a bottom side of the light tunnel  108  or into the portion  110  of the surface of the light passage section  109  facing the light tunnel  108 , which portion  110  is designed as a Petzval surface. 
         [0102]      FIG. 4  shows, by way of an enlarged representation, a cut-out of the bend  107  for transitory passing of the light tunnel  108  into the light passage section  109 , the bend  107  being formed by blank-molding and designed as a continuous, curved transition. 
         [0103]      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 designed 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 overlaying the representation of the ellipsoid  150 . For the ellipsoid  150  represented in  FIG. 7  the following applies: 
         [0000]    
       
         
           
             
               
                 
                   x 
                   2 
                 
                 
                   a 
                   2 
                 
               
               + 
               
                 
                   y 
                   2 
                 
                 
                   b 
                   2 
                 
               
               + 
               
                 
                   z 
                   2 
                 
                 
                   c 
                   2 
                 
               
               - 
               1 
             
             = 
             0 
           
         
       
     
         [0104]    Herein, there is 
         [0105]    z a coordinate in the direction of the optical axis of the light tunnel (A→B); 
         [0106]    x a coordinate orthogonal to the direction of the optical axis of the light tunnel; and 
         [0107]    y a coordinate orthogonal to the direction of the optical axis of the light tunnel and to the x-direction (D→C). 
         [0108]    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 the light entry face  101  is 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 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 . 
         [0109]      FIG. 9  shows a side elevation of a headlight lens  200  in its intended alignment (within a motor vehicle headlight), which lens  200  is to be used alternatively with regard to headlight lens  100 . The headlight lens  200  comprises a blank-molded monolithic body of inorganic glass and including a light tunnel  208 , which has a light entry face  201  on one side and, on another side, transits into a light passage or conductive section  209  (of the blank-molded monolithic body) via a bend  207  curved in three spatial dimensions, which light conductive 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 (all) 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 parallel to the optical axis of the headlight lens  200 . Herein, the light passage section  209  maps the bend  207  as a bright-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. 
         [0110]      FIG. 10  shows a headlight lens  300  by way of a side elevation in its intended alignment (within a motor vehicle headlight), which lens  300  is to be used alternatively with regard to headlight lens  100 .  FIG. 11  shows the headlight lens  300  by way of a top new 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 exit face  301  on one side and, on the other side, passes over into a light passage or conductive section  309  (of the blank-molded monolithic body) via a bend  307  curved in the two spatial dimensions, which light passage section  309  includes a light exit face  302 . The headlight lens  300  is shaped 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  maps the bend  307  as a bright-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 shaped as a Petzval surface. A rim or edge, e.g., a circumferential edge, may be provided on the section designated by reference numeral  330  of the surface of the passage section  309 , by means of which edge the headlight lens  300  may be fixed in an appropriate manner. 
         [0111]      FIG. 14  shows a side elevation of a headlight lens  400  in its intended alignment (within a motor vehicle headlight), which lens  400  is to be used alternatively with regard to headlight lens  100 .  FIG. 15  shows the headlight lens  400  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 includes a light tunnel section  408 A and a light tunnel section  408 B, which sections open out in(to) a light tunnel  408  which, in turn, transits into 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 enters the passage section from the light tunnel  408  in the region of the bend  407 , will exit from the light exit face  404  essentially in parallel to the optical axis of the headlight lens  400 . Herein, the light passage section  409  maps the bend  407  as a bright-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. 
         [0112]    At least in their upper region, the light tunnel sections  408 A and  408 B are designed—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, respectively, (in the direction of light propagation or towards the right, respectively), the surface contour of the headlight lens  400  deviates from the contour of an ellipsoid. Herein, the angles α A  and α S  indicate the directions of a deviation from the elliptic shape. 
         [0113]      FIG. 18  and  FIG. 19  show a motor vehicle headlight  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  10 A, and  FIG. 19  shows a top view of the motor vehicle headlight  10 A. The motor vehicle headlight  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  designed as LED have been provided. It may as well be provided for that in addition the light source  12  is implemented within the motor vehicle headlight  10 A. 
         [0114]    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 the light source  15  may be switched-on for the time of driving round a left corner and light source  16  may be switched-on 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.