Abstract:
An illumination device comprising a housing positionable at a distance from an area to be illuminated and having at least one lighting module, on a support in the housing, that has lighting units having the same light distribution characteristics. Each of the lighting units contains lighting elements and associated lenses arranged in front of the same in the light-emitting direction. Different lighting modules may include lighting units having different light distribution characteristics, while the lighting units have optical axes running parallel to each other. At least one lighting unit is configured such that its light distribution characteristics have at least one asymmetrical section relative to a central plane of the lighting unit.

Description:
PRIORITY CLAIM 
     This application is a continuation of pending International Application No. PCT/EP2010/056337 filed on May 10, 2010, which designates the United States and claims priority from German Patent Application No. 10 2009 021 208 filed on May 13, 2011. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a lighting device for streets, pathways and the like. Without admitting to be prior art, such light devices include a housing positioned at a distance from a surface that is to be illuminated. At least one lighting module is mounted on a support in the housing and may include a number of lamp units of equal light distribution characteristics. Each of the lamp units may have multiple light sources and lenses, which may be individually assigned to and positioned in front of these light sources in the direction of the light emission for generating a predefined light distribution pattern. The light device may include different lighting modules which are at least equipped with lamp units displaying a different light distribution characteristic. 
     2. Description of Relevant Art 
     EP 1 916 468 A1 describes a lighting device for streets, pathways and the like, with a housing containing multiple lighting modules for generating a predefined light distribution. The housing of the lighting device is mounted on a curbside pole, allowing a longitudinal section of the street to be illuminated as the object surface. The lighting modules mounted in the housing are of an elongated design and are provided with a support on which lamp units of an identical type of light distribution characteristic are installed in rows. Each lamp unit essentially consists of an LED light source and, positioned in front of it in the direction of the light emission, a lens. The lamp units of the lighting module are shielded by a common, transparent cover plate. 
     For generating a predefined light distribution of the lighting device, several lighting modules with different types of light sources and/or different light distribution characteristics are employed. A first lighting module includes lamp units with first lenses which in relation to a central plane emit a relatively narrow light cone. A second lighting module includes lamp units with second lenses which in relation to the central axis emit a relatively broad light cone. Third lighting modules include lamp units with third lenses which emit light cones in a dihedral range located between the light cone of the first lamp unit and the second lamp unit. The lighting modules with the lamp units that emit in the dihedral range a relatively narrow light cone are so positioned in the housing that they illuminate a marginal area of the surface to be illuminated. A main area of the surface to be illuminated is illuminated by the lighting modules with the broad-beam lamp units. In relation to the central axis the light cones of the different lighting modules or lamp units are symmetrical. It follows that the lighting device for homogeneously illuminating the street section is relatively complex and expensive. Another drawback is the fact that several differently configured lenses must be used. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to improve the design of a lighting device in a manner whereby, in simple fashion and as needed, a predefined light distribution is achieved for an homogeneous illumination of an area. 
     In an embodiment a lighting device for streets, pathways and the like is provided. The lighting device has a housing that may be positioned at a distance from a surface area to be illuminated. Said housing includes a support board and on the support board at least one lighting module with multiple lamp units of an identical light distribution characteristic, each containing multiple light sources. A lens may be mounted in front of each light source for generating a predefined light distribution, with different lighting modules comprising at least lamp units of a different light distribution characteristic. Lamp units of the same light distribution characteristic have optical axes that extend parallel to each other and at least of one lamp units is configured such that the light distribution characteristic generated by it includes at least one section that is asymmetric relative to a central plane of the lamp unit 
     The particular advantage of the lighting device consists in the fact that combining lamp units having an asymmetric light emission characteristic is an effective way to generate a predefined light distribution and especially a relatively homogeneous light distribution. Because the optical axes of the lamp units of identical or different types, meaning lamp units having the same or a different light distribution characteristic, extend parallel to one another, it is possible to position the lamp units or lighting modules in easy-to-install fashion in a predetermined identical or different plane. 
     The lighting device permits a modular design and at the same time to retrofit already existing, installed lighting devices for streets, pathways and the like. A three-dimensional configuration of the lighting modules is not necessary. 
     In a preferred embodiment the lamp units are provided with asymmetrically configured lenses so that on a first side, in relation to a central plane, a first partial light beam is emitted in a first dihedral range and on the opposite second side a second partial light beam is emitted in a second dihedral range different from the first dihedral range. The light distribution characteristic of the lamp units thus includes an asymmetric section, where the first dihedral range may for instance be larger than the second dihedral range. The first dihedral range can thus define a preferred direction or a preferred dihedral angle in which the flux and/or the light intensity is bigger than in the second dihedral range. 
     In further embodiment the lamp units of the same type and/or of different types are provided with identical lenses. To create a differently oriented asymmetric section of the light distribution characteristic of the lighting module in relation to the orientation of the lighting module, the lenses are rotated in a perpendicular relation to a support of the lighting module. The reference axis is offset in a coaxial or parallel position relative to the optical axis of the lamp units. Thus, merely rotating the lenses permits the generation of a different light distribution characteristic. By modular superpositioning of the light distribution characteristics or of the lighting modules the specified light distribution can be generated. 
     In another embodiment, the lamp units are mounted in rows on a common support, forming an elongated lighting module. The lighting module thus advantageously matches the dimension of conventional lighting systems which can therefore be easily retrofitted. 
     In another embodiment the lighting modules can be arranged in relation to one another in a linear and/or frame-shaped and/or square, star- or propeller- or cross-shaped pattern so that, as a function of the available or desired dimensions of the lighting device the predefined light distribution is attainable. The needed light distribution can be adjusted by selecting lighting modules of different types. 
     In another embodiment the elongated lighting modules of the same and/or different type are combined in a way as to produce an asymmetric light pattern for illuminating a relatively narrow street, with the lighting device placed in a curbside position. The orientation of the lighting modules or lamp units is so chosen that the lighting modules point in the same preferred direction. Advantageously, this permits homogeneous illumination of a predefined longitudinal section of the street. 
     In another embodiment the lighting modules are configured for illuminating a street from above the median and are arranged in a way as to ensure symmetrical illumination of both sides of the median in the predefined longitudinal section of the street. To that effect, a first half of the lighting modules points in a first preferred direction and a second half of the lighting modules points in a preferred direction opposite the former. 
     In another embodiment the lighting modules are configured for illuminating a place from a central point above the latter are so positioned that the asymmetric light distribution characteristics of the lighting modules point in four different directions, whereby, in relation to a circumferential central axis, lighting modules mutually juxtaposed at a 90° angle point in the respective preferred directions. Advantageously, this essentially permits a rotationally symmetric illumination of a street. 
     In another embodiment the lighting modules are configured for illuminating a street corner and are so arranged as to produce two partial light beams which, at a right angle to each other, point in the respective preferred directions. This permits the homogeneous illumination of a junction or a corner area at an intersection. 
     In a further embodiment the light sources include LED chips and the frame of the lighting module supporting the LED chips and the lens is shielded with a transparent cover plate. The lighting modules are thus always of the same design, while in relation to its axis of symmetry only the lens may be turned in different positions. Advantageously the lighting module is thus of a relatively simple design. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following describes exemplified embodiments in more detail with the aid of the drawings in which: 
         FIG. 1  is a perspective bottom view of a lighting device with lighting modules in a frame-shaped arrangement; 
         FIG. 2  is a bottom view of the lighting device per  FIG. 1 ; 
         FIG. 3  is a sectional view of the lighting device per  FIG. 2  along line III-III in  FIG. 2 ; 
         FIG. 4  is a perspective view of the lighting module with a partly cut-out cover plate; 
         FIG. 5  is an exploded view of the lighting module; 
         FIG. 6  is a sectional view of a lamp unit of the lighting module along line VI-VI in  FIG. 2 ; 
         FIG. 7  is a sectional view of a lamp unit of the lighting module along line VII-VII in  FIG. 2 ; 
         FIG. 8   a  is a schematic top view of a dual-frame-shaped lighting device; 
         FIG. 8   b  is a schematic top view of a dual-line-shaped lighting device; 
         FIG. 8   c  is a schematic top view of a crossform lighting device; 
         FIG. 8   d  is a schematic top view of a propeller-shaped lighting device; 
         FIG. 8   e  is a schematic top view of a linear lighting device in a first embodiment; 
         FIG. 8   f  is a schematic top view of a linear lighting device in a second embodiment; 
         FIG. 9   a  is a schematic top view of the frame-shaped lighting device per  FIGS. 1 to 3  in a first configuration in which the lighting modules point in the same preferred direction; 
         FIG. 9   b  is a schematic bird&#39;s eye view of a longitudinal street area, showing the position of the lighting device; 
         FIG. 9   c  shows an asymmetric light distribution of the lighting device per  FIG. 9   a;    
         FIG. 10   a  is a schematic top view of the frame-shaped lighting device per  FIGS. 1 to 3  in a first configuration, with each two lighting modules pointing in opposite preferred directions; 
         FIG. 10   b  is a schematic bird&#39;s eye view of a longitudinal street area, showing the position of the lighting device; 
         FIG. 10   c  shows a schematic light distribution of the lighting device per  FIG. 10   a;    
         FIG. 11   a  is a schematic top view of the frame-shaped lighting device per  FIGS. 1 to 3  in a second configuration, with each lighting module pointing in a different preferred outward direction; 
         FIG. 11   b  is a schematic bird&#39;s eye view of a longitudinal street area, showing the position of the lighting device; 
         FIG. 11   c  shows a rotationally symmetric light distribution of the lighting device per  FIG. 11   a;    
         FIG. 12   a  is a schematic top view of the frame-shaped lighting device per  FIGS. 1 to 3  in its first configuration, with each two lighting modules pointing in a preferred direction extending at a 90° angle from the other two lighting modules; 
         FIG. 12   b  is a schematic bird&#39;s eye view of a longitudinal street area, showing the position of the lighting device; and 
         FIG. 12   c  shows an angular light distribution of the lighting device per  FIG. 12   a.    
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following, the invention will be described by way of example, without limitation of the general inventive concept, on examples of embodiments and with reference to the drawings. 
       FIGS. 1 to 3  depict a first embodiment of a lighting device  1  for streets, pathways and the like. It includes a frame-shaped housing  2  mounted on a pole, not illustrated, via a base  3 . The housing  2  is thus positioned at a predefined distance from the area to be illuminated (street, pathway etc.). In combination with its base  3  the lighting device  1  is mushroom-shaped. 
     The lighting device  1  is of a segmented design, comprising multiple straight-linear lighting modules  4 , each positioned on a frame side  5  of the lighting device  1 . The frame sides  5  of the lighting device  1  delimit a square opening  6 . From corners of this frame-shaped housing  2  extend brackets  8  at an angle of about 45° relative to the pole axis or axis of symmetry  9  of the lighting device  1 . On its bottom side  10  the frame-shaped housing  2  has four recesses  11 , each associated with a frame side  5 . Each recess  11  accommodates a lighting module  4  and is shielded by a transparent cover plate  12 . 
     As can be seen especially in  FIG. 2   a  lighting module  4 ′ exhibiting a first light distribution characteristic (of a first type) is arranged at each of, the mutually opposite frame sides  5  of housing  2  while a lighting module  4 ″ having a second light distribution (of a second type) is arranged at each of two other mutually opposite frame sides  5 . The following will describe the configuration of lighting modules  4 ,  4 ′,  4 ″ in more detail with reference to  FIGS. 4 to 7 . 
       FIGS. 4 and 5  illustrate a lighting module  4 ′ of the first type. A support (support board  15 ) is mountable on the outer rim  13  of a tub-shaped lower casing  14  is. The support board  15  is in the form of an elongated, i.e. linear circuit board with eight light sources (LED light sources, LED chips  16 ) surface-mounted in a row and each covered in the main emission direction  17  by a conchiform lens  18 . Each LED chip  16  with an associated lens  18  constitutes a lamp unit  19  of a first type which emits light with a first light distribution characteristic. 
     As can be seen in  FIGS. 6 and 7 , the lamp unit  19  emits a first partial light beam  21  in relation to a central plane M that intersects an optical axis  20 , in a first dihedral range  22  which in relation to the central axis M is larger than a second dihedral range  23  in which a second partial light beam is emitted on a second side in an opposite location relative to the central axis M. This asymmetric light distribution characteristic is generated by the shape of lens  18 , whereby the light emanating from the LED chip  16  is redirected through reflection and/or refraction, so that the first partial light beam  21  and the second partial light beam  24  produce an asymmetric light distribution characteristic relative to the central plane M. In the lamp unit  19  of the first type the central plane M extends in a transverse direction in relation to the longitudinal orientation of the support board  15 . 
     As shown in  FIG. 7 , lens  18  is shaped in a way whereby, relative to a central plane N that is rotated by 90° relative to the central plane M, a partial light beam  25  is symmetrically emitted. In the lamp unit  19  of the first type the second central plane N extends in the longitudinal direction of the support board  15  and intersects the optical axis  20 . The central plane M and the second central plane N both extend in a perpendicular direction relative to the support board  15 . 
     As shown in  FIG. 6 , lens  18  features on one side a first flat wing  26  and a second steep wing  27 . The relatively flat first wing  26  results in the emission of a relatively wide first partial light beam  21  in the first dihedral range  22  (65°). The relatively steep second wing  27  leads to the emission of the second partial light beam  24  in the second dihedral range  23  (40°). The first partial light beam  21  is thus emitted at a larger angle relative to the central plane M than the second partial light beam  24 . The lamp unit  19  of the first type exhibits a preferred direction V toward a front face of support board  15  which is faced by the relatively flat wing  26  of lens  18 . The first partial light beam  21  and the second partial light beam  24  form an asymmetrical section of the light distribution characteristic relative to the central plane M. 
     A lamp unit  28  of a second type differs from lamp unit  19  of the first type in that lens  18  is positioned at a 90° angle relative to a reference axis of support board  15 . The reference axis extends coaxially with the optical axis  20  of lamp unit  28 . As shown in  FIG. 2 , the rows of lamp units  28  of the second type form lighting module  4 ″ of the second type and the flat wings  26  of the corresponding lenses  18  point in the same preferred direction V as the flat wings  26  of lenses  18  of lamp unit  19  in lighting modules  4 ′ of the first type. The result is a lighting device  1  with an asymmetric light distribution pattern (light distribution characteristic) serving to illuminate a street  29 , the lighting device  1  in this case positioned in a transitional area between the street  29  and a bicycle path/sidewalk  30 , as indicated in  FIG. 9   a ,  9   b .  FIG. 9   b  shows the pole axis of lighting device  1 ,  FIG. 9   c  illustrates the asymmetric and relatively homogeneous light distribution L 1  of lighting device  1 . 
       FIGS. 2 and 3  show that the optical axes  20  of lamp units  19  of the first type and of lamp units  28  of the second type extend parallel to each other. The support boards  15  of lighting modules  4 ,  4 ′,  4 ″ extend in a common plane perpendicular to the pole axis  9  and perpendicular to optical axis  20 . Thus, lighting modules  4 ,  4 ′,  4 ″ essentially extend in a two-dimensional space, essentially parallel to a longitudinal area  31  of the street  29  that is illuminated by the light beam of lighting device  1 . 
     It will be evident that the lamp units  19 ,  28  incorporate the same components, these being identical LED chips  16  and the same lenses  18 . The only difference is that the lenses  18  are positioned at a 90° angle to the reference axis  20 . In an alternative embodiment, not illustrated, other lighting modules may contain lamp units whose lens  18  is turned 180° relative to lens  18  of lighting module  4 ′ of the first type. As another alternative, lighting modules  4 ,  4 ′,  4 ″ may only in part contain lamp units of the same type. For example, lamp units of different types may be used in a relative long lighting module. 
     In the exemplified embodiments here described, the lighting modules  4 ,  4 ′,  4 ″ each contain lamp units whose lenses  18  are in the same position relative to support board  15  of lighting module  4 ,  4 ′,  4 ″. 
     In an alternative embodiment of a lighting device  1 ′ per  FIGS. 10   a  to  10   c , the frame-shaped housing  2 —as in lighting device  1 —may be equipped with two lighting modules  4 ′ of the first type and two lighting modules  4 ″ of the second type in which case, however, the lighting modules  4 ′ and, respectively,  4 ″ positioned on opposite frame sides  5 , point in opposite preferred directions and not—as in lighting device  1 —in the same preferred direction V. As shown in  FIG. 10   a , while lighting modules  4 ′,  4 ″ mounted on opposite frame sides  5  are of the same type, they are turned 180° relative to pole axis  9 , so that by superpositioning light beams with equally distributed preferred directions V are emitted in two opposite directions. This lighting device  1 ′ would preferably be positioned above the median  32  of street  29 , with the preferred directions V extending in a transverse relation to the median  32  for a homogeneous illumination of the longitudinal area  31  of street  29 .  FIG. 10   c  illustrates a light distribution L 2  obtained with lighting device  1 ′. 
     In another embodiment of a lighting device  1 ″ per  FIG. 11   a  to  11   c , the frame-shaped housing  2 , unlike that in lighting device  1 , may be equipped with lighting modules  4 ″ of the second type. These lighting modules  4 ″ will be positioned in a way whereby their preferred directions V point outward away from the pole axis  9 , so that lighting device  1 ″, preferably located at a central point  33  of a place  34 , can serve to homogeneously illuminate the latter as a function of the light distribution L 3 . The preferred direction V differs for each of the lighting modules  4 ″. Advantageously this permits a rotationally symmetric illumination of a place  34 . 
     In another embodiment of a lighting device  1 ′ as shown in  FIGS. 12   a  to  12   c , two lighting modules  4 ′ of the first type and two lighting modules  4 ″ of the second type may be employed, in which case there will only be two preferred directions V which in relation to the pole axis  9  are positioned at a 90° angle relative to each other. Advantageously this permits homogeneous illumination of a road junction or of the corner  35  of a street  29  as a function of the light distribution L 4  as shown in  FIG. 12   c.    
     In another embodiment according to  FIG. 8   a , two frame-shaped lighting devices  1 ′ may be combined to form a dual-frame lighting device  36 . The two frame-shaped lighting devices  1 ′ are positioned on two sides of pole axis  9  and may be attached to the pole by means of holding devices  37 . This lighting device  36  is preferably used for relatively wide streets, especially multi-lane streets, with the lighting device  36  positioned above the median  32 . 
     In another embodiment per  FIG. 8   b , a dual linear lighting device  38  may be provided, in which case two lighting modules  4  will be mounted on both sides of pole axis  9 , extending parallel to each other. 
     In another embodiment as shown in  FIG. 8   c , four lighting modules  4  may be installed in a cross like form arrangement at a 90° angle from one another so as to form a cross-shaped lighting device  39 . 
     Alternatively, a propeller-shaped lighting device  40  can be created by positioning three lighting modules  4  around the pole axis at a 120° angle. 
     In another embodiment as shown in  FIG. 8   e , a linear lighting device  41  may be provided by sequentially positioning multiple lighting modules  4  in a longitudinal direction. 
     In another embodiment of a linear lighting device  42 , the lighting modules  4  may merely by be positioned in the form of a parallel flush-mounted array. 
     The modular concept permits a simple adaptation to given lighting requirements. In particular, with only two different lighting modules  4 ′,  4 ″ it is possible to create various configurations of lighting devices. 
     The lighting device can be employed not only for street lighting but also for illuminating industrial facilities or living rooms. For example, the lighting device according to the invention can be used for illuminating moisture- and explosion-proof rooms, in a kitchen area, on furniture and the like. 
     While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. 
     It will be appreciated to those skilled in the art having the benefit of this disclosure that this invention is believed to provide lighting devices. Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims. 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 LIST OF REFERENCE NUMERALS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                  1, 1′, 1″, 1′″ 
                 lighting device 
               
               
                   
                  2 
                 frame-shaped housing 
               
               
                   
                  3 
                 base 
               
               
                   
                  4, 4′, 4″ 
                 lighting modules 
               
               
                   
                  5 
                 frame side 
               
               
                   
                  6 
                 opening 
               
               
                   
                  7 
               
               
                   
                  8 
                 brackets 
               
               
                   
                  9 
                 axis of symmetry 
               
               
                   
                 10 
                 bottom side 
               
               
                   
                 11 
                 recesses 
               
               
                   
                 12 
                 cover plate 
               
               
                   
                 13 
                 rim of opening 
               
               
                   
                 14 
                 lower casing 
               
               
                   
                 15 
                 support board 
               
               
                   
                 16 
                 LED chips 
               
               
                   
                 17 
                 main emission direction 
               
               
                   
                 18 
                 lens 
               
               
                   
                 19 
                 lamp unit 
               
               
                   
                 20 
                 optical axis 
               
               
                   
                 21 
                 first partial light beam 
               
               
                   
                 22 
                 first dihedral range 
               
               
                   
                 23 
                 second dihedral range 
               
               
                   
                 24 
                 second partial light beam 
               
               
                   
                 25 
                 light beam 
               
               
                   
                 26 
                 first flat wing 
               
               
                   
                 27 
                 second steep wing 
               
               
                   
                 28 
                 lamp unit 
               
               
                   
                 29 
                 street 
               
               
                   
                 30 
                 bicycle path/sidewalk 
               
               
                   
                 31 
                 longitudinal street area 
               
               
                   
                 32 
                 median 
               
               
                   
                 33 
                 central point 
               
               
                   
                 34 
                 place 
               
               
                   
                 35 
                 corner 
               
               
                   
                 36 
                 lighting device 
               
               
                   
                 37 
                 holding devices 
               
               
                   
                 38 
                 lighting device 
               
               
                   
                 39 
                 lighting device 
               
               
                   
                 40 
                 lighting device 
               
               
                   
                 41 
                 lighting device 
               
               
                   
                 42 
                 lighting device 
               
               
                   
                 43 
               
               
                   
                 44 
               
               
                   
                 45 
               
               
                   
                 46 
               
               
                   
                 47 
               
               
                   
                 48 
               
               
                   
                 L1 
                 light distribution 
               
               
                   
                 L2 
                 light distribution 
               
               
                   
                 L3 
                 light distribution 
               
               
                   
                 L4 
                 light distribution 
               
               
                   
                 M 
                 central plane 
               
               
                   
                 N 
                 central plane 
               
               
                   
                 V 
                 preferred direction