Light Collection and Concentration System

Abstract

A light collection and concentration system includes a primary light concentrator, a light transport structure, and a light directing structure optically associated with the primary light concentrator. The system may include an optional secondary light concentrator. Each unit-system includes a plurality of the primary light concentrators and a respective plurality of the light directing structures, and only a single light transport structure. A photo-voltaic (PV) cell may advantageously be associated with each unit-system. Solar radiation is focused by the primary concentrators onto respective light directing structures incorporated in a low aspect ratio, sheet-type waveguide light transport structure. Each respective light directing structure intercepts the focused light and deflects it transversely to travel along the length of the light transport structure primarily via total internal reflection (TIR) towards an exit-end of the light transport structure, where it can be input to the PV cell. The optional secondary light concentrator may further concentrate the light out-coupled from the transport structure into the PV cell.

1 . A light collection and concentration system, comprising:
 a primary light concentrator having a focusing power, disposed to intercept a solar light input and concentrate said input in a light concentration location;   a light transport structure having a top surface portion and an opposing bottom surface separated by an interior region, and an exit-end, characterized by a length dimension in an intended light propagation direction towards the exit-end, wherein said interior region has an index of refraction that is greater than an index of refraction immediately adjacent the top and bottom surfaces; and   a light directing structure integrally disposed in or on the light transport structure in a location that coincides with the light concentration location, which is optically coupled to the primary light concentrator, wherein the light directing structure can direct a concentrated solar light input from the primary concentrator along the intended light propagation direction towards the exit-end.   
     
     
         2 . The system of  claim 1 , comprising a plurality of the primary light concentrators and a respective plurality of the light directing structures. 
     
     
         3 . The system of  claim 2 , wherein the plurality of the primary light concentrators is in the form of a planar, spaced array. 
     
     
         4 . The system of  claim 2 , wherein the plurality of the primary light concentrators is in the form of at least a portion of immediately adjacent concentric rings, further wherein the intended light propagation direction is in a radially inward direction 
     
     
         5 . The system of  claim 2 , wherein the plurality of the primary light concentrators is in the form of immediately transversely adjacent, straight cylinders, further wherein the intended light propagation direction is transverse to the longitudinal axes of the cylinders. 
     
     
         6 . The system of  claim 1 , wherein the primary light concentrator is a reflective element. 
     
     
         7 . The system of  claim 1 , wherein the primary light concentrator is a refractive element. 
     
     
         8 . The system of  claim 1 , wherein the primary light concentrator is a diffractive element. 
     
     
         9 . The system of  claim 1 , wherein the light transport structure is in the form of a low aspect ratio sheet. 
     
     
         10 . The system of  claim 1 , wherein the light directing structure comprises an angled light-reflecting surface extending inwardly from at least one of the top surface portion and the bottom surface portion of the transport structure. 
     
     
         11 . The system of  claim 10 , wherein the light directing structure comprises a lateral cut in at least one of the top surface portion and the bottom surface portion of the transport structure. 
     
     
         12 . The system of  claim 10 , wherein the angled light-reflecting surface is flat. 
     
     
         13 . The system of  claim 10 , wherein the angled light-reflecting surface is curved. 
     
     
         14 . The system of  claim 10 , wherein the angled light-reflecting surface has a transverse extent in the transport structure that coincides with a transverse extent of a respective primary light concentrator. 
     
     
         15 . The system of  claim 10 , wherein at least one of the top surface and the bottom surface of the transport structure is flat and at least one of the bottom surface and the top surface of the transport structure is stepped, wherein the angled light-reflecting surface of the light directing structure connects a stepped region and an immediately adjacent stepped region of the transport structure. 
     
     
         16 . The system of  claim 15 , wherein the stepped regions are flat. 
     
     
         17 . The system of  claim 15 , wherein the stepped regions are inclined. 
     
     
         18 . The system of  claim 10 , wherein the angled light-reflecting surface is disposed at an angle that supports total internal reflection from the top or bottom surface immediately adjacent the angled light-reflecting surface. 
     
     
         19 . The system of  claim 10 , wherein the light directing structure is an air prism. 
     
     
         20 . The system of  claim 1 , further comprising a photo-voltaic cell disposed to receive the light out-coupled from the exit end of the light transport structure. 
     
     
         21 . The system of  claim 1 , further comprising a secondary light concentrator that is coupled to the exit-end to further concentrate and out-couple the propagated light from within the light transport structure, wherein the secondary light concentrator has an exit-end having an area that is smaller than the exit-end area of the light transport structure. 
     
     
         22 . The system of  claim 21 , wherein the secondary light concentrator is an optical element directly coupled to the exit-end of the transport structure. 
     
     
         23 . The system of  claim 21 , wherein the secondary light concentrator is in the form of an integrally shaped exit-end region of the light transport structure. 
     
     
         24 . The system of  claim 23 , wherein the secondary light concentrator is a compound parabolically-shaped exit-end region of the transport structure. 
     
     
         25 . The system of  claim 23 , wherein the secondary light concentrator is a compound trapezoidally-shaped exit-end region of the transport structure. 
     
     
         26 . The system of  claim 1 , wherein a unit-system comprises a plurality of the primary light concentrators, a respective plurality of the light directing structures, and only a single light transport structure. 
     
     
         27 . The system of  claim 26 , further comprising a photo-voltaic (PV) cell disposed in a location to receive light out-coupled from the exit-end of one of the light transport structure and an exit-end of an secondary light concentrator. 
     
     
         28 . The system of  claim 27 , wherein the secondary light concentrator is disposed between the exit-end of the light transport structure and the PV cell. 
     
     
         29 . A method for transporting light, comprising:
 collecting an initial light input;   optically concentrating said initial light input into a light concentration location;   disposing only a single light transport structure including an integral light directing structure in a location such that a location of the light directing structure coincides with the light concentration location;   changing the propagation direction of the light from an input direction outside of the light transport structure to an output direction inside of light transport structure via the light directing structure; and   propagating the light through the light transport structure to an exit end thereof and into a PV cell.   
     
     
         30 . The method of  claim 29 , comprising changing the propagation direction of the light only at a top surface region of the light transport structure. 
     
     
         31 . The method of  claim 29 , comprising changing the propagation direction of the light only at a bottom surface region of the light transport structure. 
     
     
         32 . The method of  claim 29 , comprising changing the propagation direction of the light at both a top surface region and a bottom surface region of the light transport structure. 
     
     
         33 . The method of  claim 29 , comprising changing the propagation direction of the light by approximately 90 degrees. 
     
     
         34 . The method of  claim 29 , comprising changing the propagation direction of the light only by total internal reflection. 
     
     
         35 . The method of  claim 29 , comprising propagating the light through the light transport structure only by total internal reflection. 
     
     
         36 . The method of  claim 29 , comprising propagating the light through the light transport structure by total internal reflection and diffuse reflection. 
     
     
         37 . The method of  claim 29 , comprising further concentrating the light propagating through the light transport structure prior to outputting the light from the light transport structure and inputting the light to the PV cell. 
     
     
         38 . The method of  claim 29 , comprising optically concentrating said initial light input into a circular spot. 
     
     
         39 . The method of  claim 29 , comprising optically concentrating said initial light input into a rectangular spot. 
     
     
         40 . The method of  claim 29 , comprising optically concentrating said initial light input into a non-circular, non-rectangular spot. 
     
     
         41 . The method of  claim 29 , further comprising:
 collecting a plurality of initial light inputs;   optically concentrating each of said plurality of initial light inputs into a respective plurality of light concentration locations;   
       wherein said only a single light transport structure includes a respective plurality of integral light directing structures in locations coinciding with the plurality of light concentration locations.