Waveguide Having Unidirectional Illuminance

Abstract

A luminaire includes an optical waveguide having a first surface and a second surface opposite the first surface, and a light source associated with the optical waveguide. At least about 80% of light produced by the light source is directed by the waveguide into an illumination distribution emitted from the first surface of the optical waveguide.

We claim: 
     
         1 . A luminaire, comprising:
 an optical waveguide having a first surface and a second surface opposite the first surface;   a light source associated with the optical waveguide;   wherein at least about 80% of light produced by the light source is directed by the waveguide into an illumination distribution emitted from the first surface of the optical waveguide.   
     
     
         2 . The luminaire of  claim 1 , wherein at least about 90% of light is emitted from the first surface of the optical waveguide. 
     
     
         3 . The luminaire of  claim 1 , wherein at least about 95% of light is emitted from the first surface of the optical waveguide 
     
     
         4 . The luminaire of  claim 3 , wherein the optical waveguide has an optical efficiency of at least 90%. 
     
     
         5 . The luminaire of  claim 3 , wherein the optical waveguide has an optical efficiency of at least 95%. 
     
     
         6 . The luminaire of  claim 1 , wherein the waveguide includes a plurality of extraction features disposed on the first surface. 
     
     
         7 . The luminaire of  claim 6 , wherein each extraction feature comprises an outer surface extending between an aperture adjacent the first surface of the waveguide and a base opposite the aperture, and wherein the outer surface is undercut adjacent the first surface of the waveguide. 
     
     
         8 . The luminaire of  claim 7 , wherein the plurality of extraction features includes a first extraction feature having a first height and a second extraction feature having a second height different from the first height. 
     
     
         9 . The luminaire of  claim 7 , wherein the plurality of extraction features includes a first extraction feature having a first aperture diameter and a second extraction feature having a second aperture diameter different from the first aperture diameter. 
     
     
         10 . The luminaire of  claim 7 , wherein the plurality of extraction features includes a first extraction feature having a first base diameter and a second extraction feature having a second base diameter different from the first base diameter. 
     
     
         11 . The luminaire of  claim 6 , wherein the plurality of extraction features is disposed in a hexagonal array. 
     
     
         12 . A luminaire, comprising:
 a waveguide having a first surface and a second surface opposite the first surface, wherein the waveguide includes an extraction feature disposed on the first surface; and   a light source associated with the waveguide;   wherein light emitted from the light source is directed by the waveguide into an illumination distribution emitted from the first surface of the waveguide; and   wherein the waveguide is optically transparent such that the illumination distribution is visible along a line of sight through the waveguide extending from the second surface to the first surface.   
     
     
         13 . The luminaire of  claim 12 , wherein at least about 90% of light produced by the light source is emitted from the first surface of the waveguide, and wherein the waveguide has an optical efficiency of at least 90%. 
     
     
         14 . The luminaire of  claim 12 , wherein the waveguide exhibits a luminance of less than about 5% of light produced by the light source that is visible along the line of sight. 
     
     
         15 . The luminaire of  claim 12 , wherein the extraction feature has a curved shape extending between an aperture adjacent the first surface and a base opposite the aperture. 
     
     
         16 . The luminaire of  claim 15 , wherein the curved shape has an outer surface that is determined by iteratively plotting points using a differential equation. 
     
     
         17 . The luminaire of  claim 16 , wherein the differential equation calculates the curvature of the outer surface that achieves total internal reflection of light at the outer surface of the extraction feature. 
     
     
         18 . The luminaire of  claim 17 , wherein the differential equation calculates a slope a point along the outer surface and comprises: 
       
         
           
             
               Slope 
               = 
               
                 
                   - 
                   
                     
                        
                       h 
                     
                     
                        
                       R 
                     
                   
                 
                 = 
                 
                   tan 
                   ( 
                   
                       
                   
                    
                   
                     + 
                     
                         
                     
                      
                     α 
                   
                   ) 
                 
               
             
           
         
         wherein α represents a complementary angle of a maximum angle of incidence enabling total internal reflection; 
         wherein φ is the defined by a light ray incident on the point having coordinates (h, R+R o ) relative to an edge of the aperture opposite the point, and wherein φ is calculated in accordance with: 
       
       
         
           
             
               ϕ 
               = 
               
                 ArcTan 
                  
                 
                   ( 
                   
                     n 
                     
                       R 
                       + 
                       Ro 
                     
                   
                   ) 
                 
               
             
           
         
         wherein h is a distance from the first surface of the waveguide, R O  is a radius of the aperture, and R is a distance from a centerline of the extraction feature to the point. 
       
     
     
         19 . The luminaire of  claim 15 , wherein the curved shape has a height of between about 10 μm and about 500 μm. 
     
     
         20 . The luminaire of  claim 15 , wherein the curved shape includes a first portion adjacent the aperture and a second portion adjacent the base. 
     
     
         21 . The luminaire of  claim 20 , wherein the first portion has an outer surface that is undercut relative to the first surface of the waveguide. 
     
     
         22 . The luminaire of  claim 20 , wherein the second portion has a cylindrical shape. 
     
     
         23 . The luminaire of  claim 20 , wherein the second portion has a height of between about 10 μm and about 100 μm. 
     
     
         24 . The luminaire of  claim 12 , wherein the waveguide and the extraction feature comprise the same material. 
     
     
         25 . The luminaire of  claim 12 , further comprising a member, wherein the base of the extraction feature is disposed on the member. 
     
     
         26 . The luminaire of  claim 25 , wherein the member is comprised of a material selected from the group of a film, a glass, a polyester, and an acrylic. 
     
     
         27 . The luminaire of  claim 12 , wherein a bonding feature formed atop the aperture is displaced during joining of the extraction feature to the light emitting surface of the waveguide. 
     
     
         28 . The luminaire of  claim 12 , wherein the luminaire produces an asymmetric illumination distribution. 
     
     
         29 . The luminaire of  claim 12 , wherein the luminaire has an overall efficiency of at least 90%. 
     
     
         30 . A luminaire, comprising:
 a housing;   an LED element disposed within the housing;   a waveguide having a light emitting surface disposed in the housing adjacent the LED element; and   an extraction feature disposed on the light emitting surface of the waveguide;   wherein the extraction feature has a curved shape extending between an aperture adjacent the light emitting surface and a base opposite the aperture.   
     
     
         31 . The luminaire of  claim 30 , wherein the LED element is disposed in a first end of the housing, and wherein the waveguide extends out of a second end of the housing opposite the first end. 
     
     
         32 . The luminaire of  claim 31 , wherein the LED element is disposed along a coupling surface of the waveguide.