Abstract:
The present invention relates to a light guide for lighting vehicles, preferably motor vehicles. Light rays emitted from the light source of the light guide are reflected off of reflecting surfaces toward a light exit surface. The reflected surfaces are arranged to allow full illumination of the light exit surface.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a National Stage of International Application No. PCT/DE2003/003546 filed Oct. 25, 2003, which claims priority to German Patent Application No. DE 102 51 849.1 filed on Nov. 7, 2002. The disclosures of the above applications are incorporated herein by reference. 
   TECHNICAL FIELD 
   The invention relates to a light guide for lighting vehicles, preferably motor vehicles. 
   BACKGROUND 
   There are known light guides essentially rectangular in shape and comprising lighting means in the form of LEDs arranged in series side-by-side on one narrow end. With them, light is fed into the light guide, and reflected from reflecting surfaces towards the light exit side. A uniform illumination is thus not assured. 
   The object of the invention is to configure the generic light guide such that an optimum illumination of the light guide is assured with simple design conformation. 
   This object is accomplished according to the invention, in the light guide, of the present invention. 
   SUMMARY OF THE INVENTION 
   In the light guide according to the invention, the reflecting surfaces, viewed in the direction of the rays, are offset from each other. The reflecting surfaces are so arranged that, viewed in the direction of the rays, they adjoin each other essentially without gaps. Thus, between the individual reflecting surfaces, no shadows are cast, so that the light emitted by the lighting means is optimally utilized. As a result of the configuration according to the invention, the light exit side is fully illuminated. 
   Other features of the invention will appear from the additional claims, the description and the drawings. 

   
     DESCRIPTION OF THE DRAWINGS 
     The invention will be illustrated in more detail in terms of an embodiment represented in the drawings by way of example. In the drawings, 
       FIG. 1  shows a view of a light guide according to the invention, its light guide parts being represented separately, 
       FIG. 2  shows the light guide of  FIG. 1  in perspective representation, 
       FIG. 3  shows the light guide in a view in the direction of the arrow III in  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The light guide  1  is intended for lighting of motor vehicles, and consists in known manner of light-conducting material. The light guide  1  has a rectangular outline in top view, with two plane side walls  2 ,  3  parallel to each other. On their long side, the side walls  2 ,  3  are connected to each other by a light exit surface  4 , having a rectangular outline in top view. 
   The light guide  1  is made in one piece, but consists of two light guide parts  5  and  6  each having a rectangular shape in top view. The light guide parts  5 ,  6  are essentially of like configuration, but arranged lying rotated at 180° to each other. The two light guide parts  5 ,  6  have a common light exit surface  4 . The light guide part  5  is provided at one end with a plane face  7 , extending over the entire width and height of the light guide part  5 , to which a lighting means  8 , preferably an LED, is connected. From this face  7  on out, the height of the light guide part  5  decreases in the direction of the opposed face  9 , which extends over the entire width of the light guide part  5 . 
   The other light guide part  6  likewise comprises a face  10 , rectangular in the view, which like the face  7  is of plane configuration, and to which an additional lighting means  11 , preferably an LED, is connected. The height of the light guide part  6  diminishes from this face  10  on as far as the opposed face  12 . It is of but little height, but it extends over the entire width of the light guide part  6 . As may be seen in  FIG. 2 , the faces  7 ,  12  and  9 ,  10  each lie in a common plane. The faces  7 ,  10 , like the faces  9 ,  12 , lie diagonally opposed to each other. 
   The side of the two light guide parts  5 ,  6  opposed to the light exit surface  4  is provided with reflecting surfaces  13 ,  14 , on which the light emitted from each lighting means  8 ,  11  is reflected to the light exit surface  4 . The reflecting surfaces  13 ,  14  are arranged so inclined relative to the direction of the rays that the rays of light exit from the light exit surface  4  at an angle of 90°. Depending on the application, it is of course possible to arrange the reflecting surfaces  13 ,  14  inclined at other angles, so that the light rays will exit the light exit surface  4  at angles other than 90°. 
   The reflecting surfaces  13 ,  14  are each plane and extend, as  FIG. 2  shows, over the width of the light guide part  5 ,  6  in question. The reflecting surfaces of the light guide part  5  are moreover inclined in opposed direction to the reflecting surfaces  14  of the light guide part  6 . In this embodiment by way of example, the reflecting surfaces  14  of the light guide part  6  lie parallel to each other. 
   The reflecting surfaces  13  each adjoin oblique surfaces  15  inclined in opposition to them, which in turn adjoin, at acute angles, side surfaces  16  lying perpendicular to the light exit surface  4 . These side surfaces  16  adjoin the respective reflecting surfaces  13  at obtuse angles. The oblique surfaces  15  and the side surfaces  16  form the side walls of projections  14 , triangular in cross-section. 
   In like manner, the reflecting surfaces  14  of the light guide part  6  adjoin side surfaces  18  lying perpendicular to the light exit surface  4  at obtuse angles, which surfaces  18  in turn pass over into oblique surfaces  19  at acute angles. They adjoin the reflecting surfaces  14 . The side surfaces  18  and the oblique surfaces  19  form side walls of triangular projections  20 , triangular in cross-section. 
   The reflecting surfaces  13 , as may be seen in  FIGS. 1 and 2 , lie at gap to the reflecting surfaces  14 . Accordingly, the width, measured in the direction of the rays, of the reflecting surfaces  13  is equal in size to the width, measured in the same direction, of the oblique surfaces  19 . Conversely, the width, measured in the direction of the rays, of the reflecting surfaces  14 , is equal to the width of the oblique surfaces  15 , measured in the same direction. 
   The reflecting surfaces  13 , arranged one behind another, of the light guide part  5 , from the face  7  on, have increasingly smaller distance from the light exit surface  4 . The reflecting surfaces  14  of the light guide part  6 , starting from the face  10  of this light guide part  6 , also have increasingly smaller distance from the light exit surface  4 . The reflecting surface  13 ′ of the light guide part  5 , located at half-length of the light guide  1 , passes over into the oblique surface  19 ′ of the light guide part  6 , with which it lies in a common plane. From this common surface  13 ′,  19 ′ on, in the direction of the face  7 , the light guide part  5  outreaches the light guide part  6 , while conversely, from the common surface  13 ′,  19 ′ on, towards the face  10 , the light guide part  6  outreaches the light guide part  5 . The light guide part  5 ,  6 , in its respective overreaching portion, has a plane side wall  21 ,  22  parallel to the side wall  2 ,  3  of the light guide  1 . 
   On the basis of the stepped arrangement of the reflecting surfaces  13 ,  14  and their offset arrangement to each other, it is brought about that the rays emitted by the LEDs  8 ,  11  are reflected at the reflecting surfaces  13 ,  14  to the light exit surface  4 . Thus, each light guide part  5 ,  6  generates luminous bands  23 ,  24  at the reflecting surfaces  13 ,  14 , of which three luminous bands are represented in  FIG. 1 . The luminous bands  23 ,  24  of each light guide part  5 ,  6  lie at a distance from each other. Owing to the offset arrangement of the reflecting surfaces  13 ,  14  to each other, the luminous band  24 , in side view as in  FIG. 1 , shines into the area between luminous bands  23  of the light guider part  5 . This, seen in side view, generates a continuous luminous field. 
   The reflecting surfaces  13 ,  14  are each so arranged that, seen in the direction of the rays, they adjoin each other. This means that the edge  25 , anterior in the direction of the rays, of the reflecting surface  13  adjoining the face  7 , viewed in the direction of the rays, lies at the same level as the margin  25 , posterior in the direction of the rays, of the next reflecting surface  13 . In this way, the reflecting surfaces  13  of the light guide part  5  and the reflecting surfaces  14  of the light guide part  6  are arranged one behind another. 
   Since the two lighting means  8 ,  11  are provided at the two ends of the light guide  1 , an optimal luminous yield results, with compact structure of the light guide  1 . The light is so fed into the light guide  1  that the light rays in the light guide  1  are propagated almost parallel. The stair-like reflecting surfaces  13 ,  14  with the projections  17 ,  20  located between them guide the light rays in the manner described to the light exit surface  4 . The subdivision of the deflecting optics into contrary profiles makes possible a very uniform illumination of the light exit surface  4 . It may be additionally provided with scattering and/or refracting elements to achieve a desired distribution of light. In the embodiment by way of example ( FIG. 3 ), the light exit surface  4  is provided with cushion-shaped optics  27 , immediately adjoining each other by way of the said area of the light exit surface  4 . 
   The two light sources  8 ,  11  emit light of like color. Alternatively, it is possible for the two sources  8 ,  11  to emit light of different colors. Then the light exit surface  4 , owing to the arrangement of the reflecting surfaces  13 ,  14  as described, is illuminated checkerboard-fashion by the color in question. 
   It is also possible, instead of the two light guide parts  5 ,  6 , to provide additional light guide parts, in that case arranged each rotated 180° to the respective neighboring light guide parts.