Edge lit lighting assembly with light adjustment element

Abstract

A lighting assembly comprises a light source and a light guide having a light input edge and a light output surface. Light from the light source enters the light input edge and is propagated within the light guide by total internal reflection. A light adjustment element is adjustable or selected to achieve a desired property of the light within the light guide.

What is claimed is: 
     
         1 . A lighting assembly, comprising:
 a light source;   a light guide comprising a light input edge adjacent the light source, opposed major surfaces between which light input at the light input edge propagates by total internal reflection, and a light output region associated with at least one of the major surfaces; and   a light adjustment element positioned between the light source and the light input edge of the light guide comprising a substrate and a light modifying region at the substrate configured to modify a property of the light input to the light guide;   wherein the light adjustment element is adjustable or selected to achieve a desired property of the light entering the light input edge.   
     
     
         2 . The lighting assembly of  claim 1 , wherein the light modifying region is configured to modify the ray angle distribution of at least a portion of the light entering the light input edge. 
     
     
         3 . The lighting assembly of  claim 1 , wherein the light modifying region comprises a grating. 
     
     
         4 . The lighting assembly of  claim 1 , wherein the light modifying region comprises a spectrum adjuster configured to modify the spectrum of at least a portion of the light entering the light input edge. 
     
     
         5 . The lighting assembly of  claim 4 , wherein the spectrum adjuster comprises a color-attenuating material. 
     
     
         6 . The lighting assembly of  claim 4 , wherein the spectrum adjuster comprises a wavelength-shifting material. 
     
     
         7 . The lighting assembly of  claim 4 , further comprising a light sensor to measure the spectrum of the light emitted from the light source. 
     
     
         8 . The lighting assembly of  claim 7 , further comprising a comparator for comparing the measured spectrum of the light emitted from the light source to a target spectrum of light, and a controller for controlling operation of an adjustment mechanism to position the light adjustment element as needed to obtain the target spectrum of light within the light guide. 
     
     
         9 . The lighting assembly of  claim 4 , further comprising a light sensor to measure the spectrum of the light within or extracted from the light output region of the light guide. 
     
     
         10 . The lighting assembly of  claim 9 , further comprising a comparator for comparing the measured spectrum of the light within or extracted from the light output region of the light guide to a target spectrum of light, and a controller for controlling operation of an adjustment mechanism to position the light adjustment element as needed to obtain the target spectrum of light from the light output region of the light guide. 
     
     
         11 . The lighting assembly of  claim 1 , wherein the light adjustment element is variably positionable along a lateral direction parallel to an axis defined by an intersection of the light input edge and one of the major surfaces. 
     
     
         12 . The lighting assembly of  claim 1 , wherein:
 the light adjustment element is variably positionable relative to the light guide to vary a portion of the light emitted by the light source incident thereon, and   a remainder of the light bypasses the light modifying region and mixes with the light from the light adjustment element.   
     
     
         13 . The lighting assembly of  claim 12 , wherein the light modifying region tapers in width to vary the extent to which a portion of the light is incident on the light modifying region. 
     
     
         14 . The lighting assembly of  claim 1 , wherein there are a plurality of light sources adjacent the light input edge, and the light adjusting element comprises a plurality of light modifying regions at the substrate, wherein each of the light modifying regions is associated with a respective one of the plurality of light sources. 
     
     
         15 . The lighting assembly of  claim 14 , wherein the light adjustment element comprises non-light modifying regions adjacent the light modifying regions, the light adjustment element being variably positionable to vary the position of the light modifying regions and the non-light modifying regions on which a portion of the light from the respective light sources is incident. 
     
     
         16 . The lighting assembly of  claim 1 , further comprising an adjustment mechanism to variably position the light adjustment element relative to the light guide. 
     
     
         17 . The lighting assembly of  claim 1 , wherein:
 the light adjustment element comprises an additional light modifying region having a modifying property that is different from the modifying property of the light modifying region, and   the light adjustment element is variably positionable to vary the position of the light modifying region and the additional light modifying region on which the portion of the light within the transition region is incident to vary the light within the light guide.   
     
     
         18 . The lighting assembly of  claim 1 , wherein the light adjusting element is one of a plurality of light adjusting elements between the light source and the light guide. 
     
     
         19 . The lighting assembly of  claim 1 , wherein the light source is a solid state light emitter. 
     
     
         20 . The lighting assembly of  claim 19 , wherein the solid state light emitter is a light emitting diode.