Luminaire having an asymmetrical light distribution pattern

Abstract

An apparatus is disclosed including a light guide and a plurality of light emitting diodes (LEDs). The light guide includes a rear portion including a first edge, a second edge, and a rear edge. The first edge meets the rear edge at a first obtuse angle, and the second edge meets the rear edge at a second obtuse angle. The plurality of light emitting diodes (LEDs) disposed on the first edge, the second edge, and the rear edge, and it is arranged to produce an asymmetric light distribution pattern including a rear light emission and a forward light emission having a greater peak intensity than the rear light emission.

What is claimed: 
     
         1 . An illuminator, comprising:
 a light guide including a light exit surface and a reflection surface opposite the light exit surface;   a plurality of light emitting diodes (LEDs) positioned around a perimeter of the light guide and configured to direct light into the light guide; and   a plurality of light extraction features positioned on the light guide and configured to extract light out of the light guide, the plurality of LEDs and the plurality of light extraction features being positioned such that the extracted light is distributed asymmetrically around the perimeter of the light guide.   
     
     
         2 . The illuminator of  claim 1 , wherein the plurality of light extraction features includes a plurality of prisms. 
     
     
         3 . The illuminator of  claim 2 , wherein the plurality of prisms is molded on the light guide. 
     
     
         4 . The illuminator of  claim 1 , wherein, for a first plane that is generally orthogonal to the light exit surface, the extracted light includes more light on a first side of the first plane than on a second side, opposite the first side, of the first plane. 
     
     
         5 . The illuminator of  claim 4 , wherein the plurality of light extraction features is distributed non-uniformly on the light guide. 
     
     
         6 . The illuminator of  claim 5 , wherein the plurality of light extraction features is distributed to have a higher density on the first side of the first plane than on the second side of the first plane. 
     
     
         7 . The illuminator of  claim 5 , wherein the plurality of light extraction features is distributed to have a density that varies with distance to a front edge of the light guide, the front edge being a portion of the perimeter of the light guide that is spaced farthest away from the first plane on the first side of the first plane. 
     
     
         8 . The illuminator of  claim 1 , wherein the plurality of light extraction features is positioned on the light exit surface of the light guide. 
     
     
         9 . The illuminator of  claim 1 , wherein the plurality of light extraction features is positioned on the reflection surface of the light guide. 
     
     
         10 . The illuminator of  claim 1 , wherein the plurality of LEDs is distributed uniformly around the perimeter of the light guide. 
     
     
         11 . The illuminator of  claim 1 , wherein the plurality of LEDs is distributed non-uniformly around the perimeter of the light guide. 
     
     
         12 . The illuminator of  claim 1 , wherein the light guide has a circular perimeter. 
     
     
         13 . The illuminator of  claim 1 , wherein the light guide has a polygonal perimeter. 
     
     
         14 . The illuminator of  claim 1 , wherein the light guide has a polygonal perimeter that includes at least one obtuse angle. 
     
     
         15 . A method, comprising:
 producing light with a plurality of light emitting diodes (LEDs) positioned around a perimeter of a light guide, the light guide including a light exit surface and a reflection surface opposite the light exit surface;   directing the produced light into the light guide;   directing a first portion of the light, within the light guide, to strike the light exit surface;   directing a second portion of the light, within the light guide, to reflect off the reflection surface and strike the light exit surface; and   extracting, with a plurality of light extraction features positioned on the light exit surface, at least some of the first portion of the light and at least some of the second portion of the light, the plurality of LEDs and the plurality of light extraction features being positioned such that the extracted light is distributed asymmetrically around the perimeter of the light guide.   
     
     
         16 . The method of  claim 15 , wherein, for a first plane that is generally orthogonal to the light exit surface, the extracted light includes more light on a first side of the first plane than on a second side, opposite the first side, of the first plane. 
     
     
         17 . The method of  claim 16 , wherein the plurality of light extraction features is distributed non-uniformly on the light exit surface. 
     
     
         18 . The method of  claim 16 , wherein the plurality of light extraction features is distributed to have a higher density on the first side of the first plane than on the second side of the first plane. 
     
     
         19 . The method of  claim 16 , wherein the plurality of light extraction features is distributed to have a density that varies with distance to a front edge, the front edge being a portion of the perimeter of the light guide that is spaced farthest away from the first plane on the first side of the first plane. 
     
     
         20 . An illuminator, comprising:
 a light guide including a light exit surface and a reflection surface opposite the light exit surface;   a plurality of light emitting diodes (LEDs) positioned around a perimeter of the light guide and configured to direct light into the light guide; and   
       a plurality of light extraction features positioned on the light exit surface and configured to extract light out of the light guide, the plurality of LEDs and the plurality of light extraction features being positioned such that for a first plane that is generally orthogonal to the light exit surface, the extracted light includes more light on a first side of the first plane than on a second side, opposite the first side, of the first plane.