Light Control Devices Implemented With Diffusers Having Controllable Diffusion Characteristics

Abstract

Light control devices implemented with diffusers exhibiting controllable diffusion characteristics provide anisotropic luminous intensity distributions and glare control at high viewing angles while maintaining high luminaire efficiency or daylight utilization.

I claim: 
     
         1 . A light control device implemented with a diffuser exhibiting a controllable luminous intensity distribution pattern in response to incident light, comprising:
 a substrate having first and second opposite major surfaces that receive incident light before and after, respectively, wherein said incident light propagates within said substrate;   a generally centrally located region through which a first portion of the incident light is transmitted;   a diffuser supported on said second major surface and outside of said generally centrally located region, said diffuser being of a character that diffuses a second portion of the incident light to form diffused light exhibiting a distribution pattern of luminous intensity, said diffuser and said generally centrally located region having optical properties cooperating such that said diffused light and said light transmitted through said generally centrally located region exit said light control device in a batwing luminous intensity distribution pattern;   wherein said diffuser includes a microscopic surface relief pattern formed as one of said major surfaces and further includes multiple light scattering elements, said light scattering elements producing diffused light in said batwing luminous intensity distribution pattern;   said substrate including a first and a second optically transparent portion separated by said generally centrally located region, said diffuser including first and second diffuser portions;   said incident light propagates from a light source, said first and second diffuser portions and said generally centrally located region cooperate to provide said batwing luminous intensity distribution pattern;   said first and second diffuser portion being positioned relative to said light source, said generally centrally located region positioned away from said light source, said generally centrally located region including at least one central diffuser.   
     
     
         2 . The light control device of  claim 1  wherein said at least one central diffuser is curved away from said light source. 
     
     
         3 . The light control device of  claim 1  wherein said at least one central diffuser is flat planar central diffuser. 
     
     
         4 . The light control device of  claim 1  wherein said first and said second diffuser portions are angled away from said light source. 
     
     
         5 . The light control device of  claim 1  wherein said first and said second diffusers portions are angled towards said light source. 
     
     
         6 . The light control device of  claim 1  wherein said generally centrally located region includes a first and a second central diffuser. 
     
     
         7 . The light control device of  claim 1  wherein said central diffuser includes a microscopic surface relief pattern formed as one of said major surfaces and further includes multiple light scattering elements, said light scattering elements producing diffused light in said batwing luminous intensity distribution pattern. 
     
     
         8 . A light control device implemented with a diffuser exhibiting a controllable luminous intensity distribution pattern in response to incident light, comprising:
 a substrate having first and second opposite major surfaces that receive incident light before and after, wherein said incident light propagates within said substrate;   said substrate including a first and a second optically transparent portion separated by a generally centrally located region;   said generally centrally located region through which a first portion of the incident light is transmitted, said generally centrally located region including at least one central substrate;   a diffuser including first and second diffuser portions supported on said second major surface of said respective first and second optically transparent portions and outside of said generally centrally located region, said diffuser being of a character that diffuses a second portion of the incident light to form diffused light exhibiting a distribution pattern of luminous intensity, said diffuser and said generally centrally located region having optical properties cooperating such that said diffused light and said light transmitted through said generally centrally located region exit said light control device in a batwing luminous intensity distribution pattern;   wherein said diffuser includes a microscopic surface relief pattern formed as one of said major surfaces and further includes multiple light scattering elements, said light scattering elements producing diffused light in said batwing luminous intensity distribution pattern;   wherein said incident light propagates from a light source, said first and second diffuser portions and said generally centrally located region cooperate to provide said batwing luminous intensity distribution pattern.   
     
     
         9 . The light control device of  claim 8  wherein said at least one central substrate has at least one central diffuser which includes a microscopic surface relief pattern and further includes multiple light scattering elements, said light scattering elements producing diffused light in said batwing luminous intensity distribution pattern. 
     
     
         10 . The light control device of  claim 9  wherein said at least one central diffuser includes a first and a second central diffuser angled away from said light source respectively positioned on a first and a second central substrate. 
     
     
         11 . The light control device of  claim 10  wherein said at least one central diffuser further includes a microscopic surface relieve pattern positioned on a major surface of said substrate. 
     
     
         12 . The light control device of  claim 11  wherein said major surface is an inner surface adjacent said light source. 
     
     
         13 . The light control device of  claim 11  wherein said major surface is an outer surface away from said light source. 
     
     
         14 . The light control device of  claim 9  wherein said at least one central substrate is a flat planar central substrate. 
     
     
         15 . The light control device of  claim 9  wherein said at least one central substrate is a curved central substrate. 
     
     
         16 . A light control device implemented with a diffuser exhibiting a controllable luminous intensity distribution pattern in response to incident light, comprising:
 a light control housing supporting a first and second optically transparent substrate, said first and second optically transparent substrates separated by a generally centrally located region;   each of said first and second optically transparent substrates having first and second opposite major surfaces that receive incident light before and after, wherein said incident light propagates through said substrate;   a first portion of said incident light transmitted through said generally centrally located region, said generally centrally located region including at least one central substrate;   a light source positioned within said light control housing and substantially above said at least one central substrate;   first and second diffuser portions supported on one of said major surfaces of said respective first and second optically transparent substrates and outside of said generally centrally located region, said first and second diffuser portions being of a character that diffuses a second portion of the incident light to form diffused light exhibiting a distribution pattern of luminous intensity, said first and second diffuser portions and said generally centrally located region having optical properties cooperating such that said diffused light and said light transmitted through said generally centrally located region exit said light control device in a batwing luminous intensity distribution pattern;   wherein said first and second diffuser portions include a microscopic surface relief pattern formed as one of said major surfaces and further includes multiple light scattering elements, said light scattering elements producing diffused light in said batwing luminous intensity distribution pattern;   said incident light propagates from said light source, said first and second diffuser portions and said generally centrally located region cooperate to provide said batwing luminous intensity distribution pattern.   
     
     
         17 . The light control device of  claim 16  wherein said at least one central substrate is a first and a second central substrate angled away from said light source. 
     
     
         18 . The light control device of  claim 16  wherein said at least one central substrate is a flat planar substrate positioned substantially below said light source. 
     
     
         19 . The light control device of  claim 16  wherein said at least one central substrate is curved away from said light source. 
     
     
         20 . The light control device of  claim 16  wherein said at least one central substrate includes a central diffuser, said central diffuser include a microscopic surface relief pattern thereon and further includes multiple light scattering elements, said light scattering elements producing diffused light in said batwing luminous intensity distribution pattern. 
     
     
         21 . The light control device of  claim 20  wherein said first and second optically transparent substrates are tilted at an angle with respect to a central axis of said light control housing. 
     
     
         22 . The light control device of  claim 21  wherein said angle is an acute angle. 
     
     
         23 . The light control device of  claim 21  wherein said angle is an obtuse angle.