# Patent

## Title
Apparatus for the collection and transmission of electromagnetic radiation

## Abstract

A collector for propagating incident radiation is disclosed. The collector may comprise a light directing component coupled to a buffer component, a first propagation component coupled to the buffer component and configured to transmit the incident radiation into a collector region through one of a plurality of windows, and an optical transport assembly coupled to an end of the collector region and having a second propagation component. Each light directing component may be configured to redirect the incident radiation from a first direction to a second direction, and the collector region may include a plurality of regions exhibiting a refractive index value that gradually transitions from about 1.5 to about 2.0. The second propagation component may be further configured to retain the incident radiation.

## Background
REFERENCE TO RELATED APPLICATIONS
The present application is a continuation of U.S. patent application Ser. No. 12/042,214, filed Mar. 4, 2008, which is a continuation of U.S. patent application Ser. No. 11/623,208, filed Jan. 15, 2007, now U.S. Pat. No. 7,369,735, which is a continuation-in-part of U.S. patent application Ser. No. 11/215,789, filed Aug. 30, 2005, now U.S. Pat. No. 7,164,839, which is a divisional of U.S. patent application Ser. No. 10/369,052, filed Feb. 18, 2003, now U.S. Pat. No. 6,957,650, the disclosures of which are hereby expressly incorporated in their entirety by this reference. This patent application also claims the benefit of U.S. Provisional Application No. 60/357,705, filed on Feb. 15, 2002, the disclosure of which is hereby expressly incorporated by reference.


BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to collectors configured to collect electromagnetic radiation and in particular, collectors configured to collect solar radiation and further relates to optical connectors for coupling radiation from a first optical component to a second optical component.
Solar energy collectors have used holographic elements to alter the direction of incident sunlight. Such example solar collectors include U.S. Pat. Nos. 4,863,224; 5,877,874, and 6,274,860. However, each of these systems discuss the need to alter the holographic element at various spatial regions in order to avoid unwanted decoupling of solar energy from the solar collector. Such requirements result in complex systems which are not practical.
In one exemplary embodiment of the present invention, a radiation collector configured to collect incident radiation is provided. The radiation collector includes a radiation directing component configured to redirect the incident radiation, a buffer component configured to receive the radiation redirected by the radiation directing component, and a propagation component configured to receive the radiation from the buffer component and to propagate the radiation by at least total internal reflection. Other embodiments of the present invention further include connectors for coupling radiation from a first optical component to a second optical component.
In another exemplary embodiment, a collector for collecting radiation incident on the collector from at least a first direction comprises a propagation component configured to transmit radiation and having a first end and at least a first refractive index; a buffer component coupled to the propagation component and configured to transmit radiation and having at least a second refractive index, the second refractive index being less than the first refractive index of the propagation component; and a radiation directing component coupled to the buffer component and configured to redirect the incident radiation from the at least first direction along at least a second direction different than the first direction within the buffer component, such that the radiation enters the propagation component and is propagated within the propagation component toward a first end of the propagation component by at least total internal reflection. In one example, the radiation is solar radiation and the buffer component is positioned relative to the propagation component and the radiation directing component, such that the radiation propagating in the propagation component is prevented from interacting with the radiation directing component.
In yet another exemplary embodiment, a collector for collecting radiation incident on the collector from at least a first direction comprises a radiation directing component configured to redirect the incident radiation; a buffer component coupled to the radiation directing component and configured to receive the radiation redirected by the radiation directing component; and a propagation component coupled to the buffer component and configured to receive the radiation from the buffer component and to propagate the radiation generally in a first direction toward a first end of the propagation component by at least total internal reflection, the radiation directing component being positioned such that the radiation incident on the collector which is received into the propagation component is incident from a direction generally not parallel with the first direction of the propagation component.
In a further exemplary embodiment, a solar collector configured to collect incident solar radiation and to be affixed to a surface of a building comprises an optical component having a top surface and a first end, the optical component configured to receive the incident solar radiation through the top surface and to collect the incident solar radiation at the first end of the optical component; and an attachment component coupled to the optical component, the attachment component configured to receive at least one fastening components to secure the attachment component to the surface of the building.
In one exemplary method, a method of collecting incident radiation comprises the steps of receiving the incident radiation from at least a first direction; redirecting the incident radiation with a radiation directing component into a propagation component; retaining the radiation in the propagation component such that the radiation is propagated generally toward a first end of the propagation component; and optically separating the radiation component from the propagation component such that the radiation propagating with the propagation component is prevented from interacting with the radiation directing component.
In another exemplary method, a method of coupling optical radiation from at least a first source of optical radiation into a first optical transport component including a first propagation component and a first buffer component, the first buffer component radially overlaying the first propagation component and the first optical transport component configured to propagate optical radiation in generally a first direction toward a first end of the first optical transport component or in generally a second direction toward a second end of the first optical transport component comprises the steps of positioning the at least first source of optical radiation adjacent an exterior radial surface of the first buffer component; and directing at least a portion of the radiation emanating from the source of optical radiation into the first buffer component of the first optical transport component such that the radiation is coupled into the first propagation component and is propagated within the first propagation component toward at least one of the first end or the second end of the first propagation component due at least to total internal reflection between the first propagation component and the second component.
In yet a further exemplary embodiment, an optical connector for transferring radiation comprises a first optical transport component including a first propagation component and a first buffer component, the first buffer component radially overlaying the first propagation component, the first optical transport component configured to propagate optical radiation in generally a first direction toward a first end of the first optical transport component; a second optical transport component including a second propagation component and a second buffer component, the second buffer component radially overlaying the second propagation component, the second optical transport component configured to propagate optical radiation in generally a second direction toward a second end of the second optical transport component, the second optical transport component being positioned such that the second direction is not parallel to the first direction; and a radiation directing component located proximate to the first end of the first optical transport component and proximate to an exterior surface of the buffer component of the second optical transport component, the radiation directing component configured to redirect the optical radiation propagating generally in the first direction through the exterior surface of the second optical transport into the second propagation component such that the optical radiation is propagated within second optical transport component generally along the second direction of the second optical transport component.
In still another exemplary embodiment, a method of propagating collected incident radiation to a remote location is provided. The method comprises receiving the incident radiation from at least a first direction; redirecting the incident radiation with a light directing component into a first propagation component having a plurality of windows contained therein, the light directing component being coupled to a buffer component configured to optically separate the light directing component and the first propagation component and to retain the incident radiation in the first propagation component; propagating the incident radiation into a collector region through one of the plurality of windows within the first propagation component; advancing the incident radiation within the collector region generally towards an end of the collector region, the radiation encountering a plurality of regions exhibiting a refractive index value that gradually transitions from about 1.5 to about 2.0 while advancing towards the end of the collector region; and directing the incident radiation into an optical transport assembly having a second propagation component, the second propagation component being configured to retain the incident radiation therein for being propagated to the remote location.
In another exemplary embodiment, a collector for propagating incident radiation to a remote location is provided. The collector comprises a light directing component coupled to a buffer component, each light directing component being configured to redirect the incident radiation from a first direction to a second direction; a first propagation component coupled to the buffer component and configured to transmit the incident radiation into a collector region through one of a plurality of windows, the collector region including a plurality of regions exhibiting a refractive index value that gradually transitions from about 1.5 to about 2.0; and an optical transport assembly coupled to an end of the collector region and having a second propagation component, the second propagation component being configured to retain the incident radiation
Additional features of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived.



BRIEF DESCRIPTION OF THE DRAWINGS
The detailed description of exemplary embodiments particularly refers to the accompanying figures in which:
FIG. 1 is an exploded, perspective view of a first embodiment of a solar collector including a radiation directing component, a buffer component, and a propagation component;
FIG. 2 is a cross-section view of the solar collector of FIG. 1 corresponding to the solar collector in an assembled configuration;
FIG. 3 is an exploded, perspective view of a second embodiment of a solar collector including a radiation directing component, a first buffer component, a propagation component, and a second buffer component;
FIG. 4 is a cross-section view of the solar collector of FIG. 3 corresponding to the solar collector in an assembled configuration;
FIG. 5 is a perspective view of a third embodiment of a solar collector including a radiation directing component, a propagation component, and a buffer component, the buffer component surrounding the propagation component except for at least a first surface of the propagation component;
FIG. 6A is a diagrammatic representation of a non-tracking embodiment of the present invention including a solar collector coupled to an energy converting component;
FIG. 6B is a diagrammatic representation of a tracking embodiment of the present invention including a solar collector coupled to a frame and to an energy converting component, the frame and the solar collector being moveable and positionable by a tracking component;
FIG. 6C is a diagrammatic representation of a tracking embodiment of the present invention including a solar collector, coupled to an energy converting component, the solar collector and the energy converting component being coupled to a frame, the frame, solar collector, and energy converting component being moveable and positionable by a tracking component;
FIG. 7A is top view of the solar collector of FIG. 5 coupled to a second solar collector and an optical transport component through an adaptor component, the adapter component tapering from a generally quadrilateral cross-section to a generally circular cross-section;
FIG. 7B is a cross-section view of the solar collector and second solar collector of FIG. 7A;
FIG. 7C is a perspective view of the solar collector of FIG. 7A showing the adapter and the optical transport component in an exploded configuration;
FIG. 7D is a side view of the solar collector of FIG. 7A and a second solar collector having a generally circular cross-section;
FIG. 7E is a side view of a first and a second solar collector coupled to an intermediate solar collector, the intermediate solar collector having a first radiation directing component for coupling the first solar collector and a second radiation directing component for coupling the second solar collector;
FIG. 8 is a schematic, side, elevational representation of a building having a plurality of solar collectors affixed to a roof of the building;
FIG. 9A is a perspective view of a first embodiment of a solar sheeting, the solar sheeting comprising a solar collector coupled to an attachment component;
FIG. 9B is an exploded, perspective view of a second embodiment of a solar sheeting, the solar sheeting comprising a solar collector and an attachment component;
FIG. 10 is an exploded, perspective view of a solar collector including a plurality of radiation directing components positioned within a first buffer component, a propagation component, and a second buffer component;
FIG. 11 is a cross-section view of the solar collector of FIG. 10 corresponding to the solar collector in an assembled configuration;
FIG. 12A is a perspective view of an exemplary optical connector in an assembled configuration;
FIG. 12B is an exploded, perspective view of the optical connector of FIG. 12A;
FIG. 13 is a diagrammatic view of an optical network;
FIG. 14 is a cross-section view of an optical transport component for connecting two solar collectors;
FIGS. 15a and 15b are exploded perspective views of additional exemplary photocollector embodiments in accordance with the present teachings;
FIG. 15c is a perspective view of the photocollector of FIG. 15a showing the optical transport component in an exploded configuration;
FIG. 16 is a cross-section view of the photocollector of FIG. 15a shown in an assembled configuration; and
FIG. 17 shows a cross-section view of the buffer component region of the photocollector from FIG. 15a showing the interaction of light rays with the concavity design of the louvers.



DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
While the invention is susceptible to various modifications and alternative forms, exemplary embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Referring to FIG. 1, a first embodiment of a radiation or solar collector 100 is shown. Solar collector 100 includes a radiation or light directing component 110, a buffering component 120, and a propagation component 130. As described in detail below, radiation or light directing component 110 is configured to redirect at least a portion of the incident solar radiation 140 on solar collector 100 into propagation component 130, propagation component 130 is configured to collect the portion of solar radiation redirected by light directing component 110, and buffer component 120 is configured to optically separate light directing component 110 and propagation component 130 and to retain the collected radiation in propagation component 130.
Referring to FIG. 2, a schematic cross-section of an assembled solar collector 100 is shown, along with the interaction of incident solar rays 140a, and 140b with solar collector 100. Rays 140a and 140b are representative of the incident solar radiation. Although light rays 140a and 140b are generally incident on solar collector 100 from a direction 139, it is understood that the incident solar radiation may be from one or more additional directions. In the illustrated embodiment, light directing component 110 and buffer component 120, as well as buffer component 120 and propagation component 130 are coupled together with at least one of a variety of optical adhesives known in the art for coupling optic media. Exemplary optical adhesives include optical epoxies and optical cements. Exemplary optical epoxies include epoxies available from MasterBond, Inc. located at 154 Hobart Street in Hackensack, N.J. 07601 and exemplary cements from Summers Optical located at 321 Morris Road, PO Box 162 in Fort Washington, Pa. 19034. It is preferred to use optical adhesives which are index matching adhesives which have an index of refraction in close approximation to at least one of the components being coupled together. It is preferred to use optical adhesives which are configured for use in applications that are exposed to long durations of solar radiation.
Radiation or light directing component 110 is configured to redirect solar radiation incident from at least a first direction 139, as represented by rays 140a and 140b along at least a second direction 143 into buffer component 120, as represented by rays 142a and 142b. Rays 142a and 142b propagate through buffer component 120 and are incident on propagation component 130 at an angle, θ142a and θ142b respectively, with the normal of an interface 124 between buffer component 120 and propagation component 130 such that rays 142a and 142b are refracted into propagation component 130 as light rays 144a and 144b. Light rays 144a and 144b propagate in propagation component 130 generally in a direction 141 toward a first end 132 of solar collector 100. The direction of light rays 142a and 142b, as well as, the properties of buffer component 120 and propagation component 130 are chosen such that light rays 144a and 144b are retained within propagation component 130 at subsequent interactions with interface 124 between buffer component 120 and propagation component 130 and a lower interface 126 between propagation component 130 and the outside medium, such as air. In one example, light rays 144a and 144b are retained within propagation component 130 by substantially total internal reflection. In another example, interface 126 includes a reflection coating (not shown), such as a mirrored surface, and light rays 144a and 144b are retained within propagation component 130 due to being reflected by the reflection coating on interface 126. In another example, light rays 144a and 144b are retained in propagation component 130 due to at least one of total internal reflection and reflection from a reflection coating. In yet a further example, at least one edge surface 121 and 131, of either or both buffer component 120 and propagation component 130 includes a reflection coating to retain solar radiation in buffer component 120 and propagation component 130. However, it should be noted that solar radiation may also be retained in propagation component 130 at surface 131 and buffer component 120 at surface 121 due to total internal reflection.
Light directing component 10, in a first embodiment, includes a holographic element, such as a film hologram or a volume hologram. In a second embodiment, light directing component 110 includes a diffraction grating or ruling. The design of holographic elements and/or diffraction gratings or rulings to redirect light incident from at least a first direction 139, such as the direction of light rays 140a and 140b in FIG. 2, along at least a second direction 143, such as the direction of light rays 142a and 142b is known.
Holographic elements are generally configured to redirect radiation that has a wavelength band approximate in value to the wavelength used to record the holographic element. Since solar radiation includes radiation at many different wavelengths, including the entire visible spectrum, it is preferred to use holographic elements which are configured to redirect incident radiation from multiple wavelength bands along at least the second direction 143. In one example, light directing component 110 contains multiple layered holographic elements, each holographic element being configured to redirect radiation approximate to a different wavelength band. In another example, multiple wavelengths are used in the recording of light directing component 110 in a single film. Light directing component 110 includes a plurality of fringe patterns each created by a recording beam pair having a different recording wavelength such that the resultant light directing component is capable of redirecting radiation from several different wavelengths.
Further, holographic elements are generally configured to redirect radiation that is incident from one of the directions used to record the holographic element, the directions of the recording beam pairs. Since solar radiation is incident on solar collector 100 from directions in addition to first direction 139, it is preferred to use holographic elements which are configured to redirect radiation from multiple incident directions including direction 139 along at least second direction 143 or other directions that allow the radiation to be propagated within the corresponding propagation component 130 by total internal reflection and/or reflection from a reflection coating. In one example, light directing component 110 contains multiple layered holographic elements, each holographic element being configured to redirect radiation from a different given incident direction such that the radiation is propagated in the propagation component by total internal reflection and/or reflection from a reflection coating. In another example, light directing component 110 includes a plurality of fringe patterns in a single film produced by recording a plurality of recording beams pairs each of which interfere to produce a holographic structure which will accept light from a range of input angles and output the light into a different range of angles chosen such that the output light is coupled into the propagation component.
Diffraction gratings and ruling can also be configured to redirect radiation of several wavelength bands and radiation from several incident directions into the propagation component such that the radiation is propagated in the propagation component by total internal reflection and/or reflection from a reflection coating. For example, the spacing of the grating can be varied either along a lateral extent of the grating or by placing gratings having different spacing adjacent each other.
In the illustrated embodiment, buffer component 120 is a refractive media having at least a first index of refraction, denoted as n120, propagation component 130 is a refractive media having at least a second index of refraction, denoted as n130, and the index of refraction of the outside media at the lower interface 126 is denoted as nout. Both buffer component 120 and propagation component 130 are manufactured from materials having a high degree of optical transmission and low adsorption properties. Further, the index of refraction of propagation component 130, n130, has a greater value than the index of refraction of buffer component 120, n120, and the index of refraction of the outside medium, nout, thereby permitting total internal reflection of the solar radiation in propagation component 130.
In one example propagation component 130 includes a refractive media such as a suitable plastic or glass and buffer component 120 includes a refractive media having a low index of refraction than propagation component 130, the buffer refractive media being a suitable plastic, glass, liquid or air. In another example the propagation component or the propagation component and the buffer component have a graded-index profile.
Referring to FIG. 2, as already noted, light rays 140a and 140b are incident from at least a first direction 139 and are redirected by light directing component 110 along at least second direction 143 as light rays 142a and 142b. Further, light rays 142a and 142b are refracted into propagation component 130 as light rays 144a and 144b and subsequent rays, such as 146a and 146b and 148a and 148b. The propagation of light ray 144b is governed by the same principles as light ray 144a. As such, it is understood that the following discussion of the propagation of light ray 144a is representative of light rays 144a and 144b, as well as additional light rays.
The direction of light ray 144a in propagation component 130 relative to the normal of interface 124 at the point of entry of light ray 144a is governed by the equation:

n120 Sin(θ142a)=n130 Sin(θ144a1)  (1)

Light ray 144a travels through propagation component 130 and is incident on interface 126 at an angle θ144a2 with respect to the normal of interface 126 at the point of incidence of light ray 144a. At interface 126 light ray 144a will be either refracted into the outside media or be reflected within propagation component 130 as light ray 146a. The direction of light ray 146a is governed by the equation:

n130 Sin(θ144a2)=nout Sin(θout)  (2)

The angle θout corresponds to the angle light ray 146a would make with the normal of interface 126 at the point of incidence of light ray 144a if light ray 146a is refracted into the outside media, nout.
Light ray 146a may be retained within propagation component 130 by either reflection from a reflection coating (not shown) at interface 126 or by total internal reflection at interface 126. In order for light ray 146a to be totally internally reflected within propagation component 130, θout must be equal to or greater than 90°, such that θ144a1 is less than or equal to 90°. The value of θout may be greater than or equal to 90° when nout is less than n130. As such, in order for light ray 146a to be totally internally reflected the following restriction should be satisfied:




  
    
      
        
          
            θ
            
              144
              ⁢
              
                
              
              ⁢
              a
              ⁢
              
                
              
              ⁢
              2
            
          
          ≥
          
            
              Sin
              
                -
                1
              
            
            ⁡
            
              (
              
                
                  n
                  out
                
                
                  n
                  130
                
              
              )
            
          
        
        ⁢
        
          

        
        ⁢
        
          
            where
            ⁢
            
              
            
            ⁢
            
              n
              out
            
          
          <
          
            n
            130
          
        
      
    
    
      
        (
        3
        )
      
    
  




Therefore, as long as θ144a2 is greater than or equal to the quantity Sin−1 (nout/n130), light ray 144a is totally internally reflected within propagation component 130 as light ray 146a. However, if θ144a2 is less than the quantity Sin−1 (nout/n130), light ray 144a may still be reflected into propagation component 130 due to a reflection coating at interface 126. As seen from equation (3), the difference in value of nout and n130 controls the range of acceptable angles, θ144a2, for total internal reflection. Table 1 shows the difference in acceptable angles, θ144a2, for various exemplary combinations of nout and n130.







TABLE 1





Comparison of Acceptable angles for total internal reflection

















nout = 1.0 (air)
n130 = 1.49 (acrylic)
θ144a2 ≧ 42.2°


nout = 1.0 (air)
n130 = 1.586 (polycarbonate)
θ144a2 ≧ 39.1°


nout = 1.49 (acrylic)
n130 = 1.586 (polycarbonate)
θ144a2 ≧ 70.0°


nout = 1.49 (acrylic)
n130 = 2.02 (glass N-LASF35)*
θ144a2 ≧ 47.5°





*N-LASF35 glass along with additional suitable glass is available from Schott-Glas located at Business Segment Display, Hattenbergstr. 10, 55122 Mainz, Germany.






As seen in Table 1, the larger the difference in nout and n130 the greater range of acceptable angles, θ144a2, that satisfy the condition of equation (3).
In the same manner light ray 146a is totally internally reflected at interface 124 as light ray 148a when θ146a2 is greater than or equal to the quantity Sin−1 (n120/n130) as expressed in equation (4).




  
    
      
        
          
            θ
            
              146
              ⁢
              
                
              
              ⁢
              a
              ⁢
              
                
              
              ⁢
              2
            
          
          ≥
          
            
              Sin
              
                -
                1
              
            
            ⁡
            
              (
              
                
                  n
                  120
                
                
                  n
                  130
                
              
              )
            
          
        
        ⁢
        
          

        
        ⁢
        
          
            where
            ⁢
            
              
            
            ⁢
            
              n
              120
            
          
          <
          
            n
            130
          
        
      
    
    
      
        (
        4
        )
      
    
  




As such, light ray 144a remains in propagation component 130 and propagates toward first end 132 of propagation component 130 as long as the relations in equations (3) and (4) are satisfied. It is understood that subsequent rays such as light ray 148a are retained in propagation component 130 as light ray 150a by reflection from a reflection coating or by total internal reflection.

It should be noted that although solar collector 100 is shown in FIG. 2 as a planar device, the invention is not limited to planar solar collectors nor are equations (3) and (4). On the contrary, in one embodiment, solar collector 100 is made of flexible material such that light directing component 110, buffer component 120 and propagation component 130 are not rigid, but able to bend. Further, propagation component 130 may be tapered such that an overall height or width of propagation component 130 is reduced or enlarged. However, in order for the solar collector to capture solar radiation in propagation component 130 and have that solar radiation propagate towards first end 132, the degree of bend of propagation component 130 and buffer component 120 or the degree of tapering of propagation component 130 is restricted by the angular requirement for total internal reflection given above in equations (3) and (4).
Further, in one variation, solar collector 100 includes a protective layer of material (not shown) that protects light directing component 110 from direct exposure to the elements and other sources of possible damage.
In one embodiment of solar collector 100, light directing component 110 is configured to redirect incident solar radiation by reflection instead of transmission. As such, incident solar radiation from a direction 145, shown in FIG. 2 passes through propagation component 130 and buffer component 120 and is incident on light directing component 110. Light directing component 110 is configured to redirect the incident solar radiation back through buffer component 120 and wherein the solar radiation is retained in propagation component 130 due to at least total internal reflection. In one example light directing component 110 includes a holographic element configured to reflect the incident solar radiation.
Referring to FIG. 3, a solar collector 200 is shown. Solar collector 200 is generally identical to solar collector 100 and comprises a light directing component 210, a first buffer component 220, a propagation component 230, and a second buffer component 260 which is coupled to the lower side of propagation component 230. Light directing component 210, in one example, includes a holographic element. Light directing component 210, in another example, includes a diffraction grating or ruling. Propagation component 230, in one example, is made of a refractive media such as a suitable plastic or glass or liquid. Buffer components 220 and 260, in one example, are comprised of a refractive media having a lower index of refraction than propagation component 230 such as a plastic material, a glass material, a liquid, or air.
Light directing component 210, first buffer component 220, propagation component 230 and second buffer component 260 are coupled together with a suitable optical adhesive. Second buffer component 260 provides protection to propagation component 230 to minimize potential damage to propagation component 230. Further, as indicated in FIG. 4, second buffer component 260 has an index of refraction, n260, which is equal to the index of refraction of first buffer component 220, n220. As such, the range of acceptable angles, θ244a2 and θ246a2 for total internal reflection, are the same for both interface 224 and interface 226. In one embodiment, interface 226 between propagation component 230 and second buffer component 260 includes a reflection coating to reflect rays not within the range of acceptable angles. In another embodiment, surfaces 221, 231, and 261 of first buffer component 220, propagation component 230, and second buffer component 260 include a reflection coating.
Referring to FIG. 4, light rays 240a and 240b are redirected by light directing component 210 from at least a first direction 239 along at least a second direction 243 as light rays 242a and 242b. Further, light rays 242a and 242b are refracted into propagation component 230 as light rays 244a and 244b and subsequent rays, such as 246a and 246b and 248a and 248b. The propagation of light ray 244b is governed by the same principles as light ray 244a. As such, it is understood that the following discussion of the propagation of light ray 244a is representative of light rays 244a and 244b, as well as additional light rays.
The direction of light ray 244a in propagation component 230 relative to the normal of interface 224 at the point of entry of light ray 244a is governed by the equation:

n220 Sin(θ242a)=n230 Sin(θ244a1)  (5)

Light ray 244a travels through propagation component 230 and is incident on interface 226 at an angle θ244a2 with respect to the normal of interface 226 at the point of incidence of light ray 244a. At interface 226 light ray 244a will be either refracted into second buffer component 260 or be reflected within propagation component 230 as light ray 246a. The direction of light ray 246a is governed by the equation:

n230 Sin(θ244a2)=n260 Sin(θ260)  (6)

The angle θ260 corresponds to the angle light ray 246a would make with the normal of interface 226 at the point of incidence of light ray 244a if light ray 244a is refracted into second buffer component 260. In order for light ray 246a to be totally internally reflected within propagation component 230, θ260 must be equal to or greater than 90°, such that θ246a1 is less than or equal to 90°. The value of θ260 may be greater than or equal to 90° when n260 is less than n230. As such, in order for light ray 246a to be totally internally reflected the following restriction should be satisfied:




  
    
      
        
          
            θ
            
              244
              ⁢
              
                
              
              ⁢
              a
              ⁢
              
                
              
              ⁢
              2
            
          
          ≥
          
            
              Sin
              
                -
                1
              
            
            ⁡
            
              (
              
                
                  n
                  260
                
                
                  n
                  230
                
              
              )
            
          
        
        ⁢
        
          

        
        ⁢
        
          
            where
            ⁢
            
              
            
            ⁢
            
              n
              260
            
          
          <
          
            n
            230
          
        
      
    
    
      
        (
        7
        )
      
    
  




Therefore, as long as θ244a2 is greater than or equal to the quantity Sin−1 (n260/n230), light ray 244a is totally internally reflected within propagation component 230 as light ray 246a. As seen from equation (7), the difference in value of n230 and n260 controls the range of acceptable angles, θ244a2, for total internal reflection. The larger the difference in n260 and n230 the greater range of acceptable angles, θ244a2, that satisfy the condition of equation (7).

In the same manner light ray 246a is totally internally reflected at interface 224 as light ray 248a when θ246a2 is greater than or equal to the quantity Sin−1 (n220/n230) as expressed in equation (8).




  
    
      
        
          
            θ
            
              246
              ⁢
              
                
              
              ⁢
              a
              ⁢
              
                
              
              ⁢
              2
            
          
          ≥
          
            
              Sin
              
                -
                1
              
            
            ⁡
            
              (
              
                
                  n
                  220
                
                
                  n
                  230
                
              
              )
            
          
        
        ⁢
        
          

        
        ⁢
        
          
            where
            ⁢
            
              
            
            ⁢
            
              n
              220
            
          
          <
          
            n
            230
          
        
      
    
    
      
        (
        8
        )
      
    
  




As such, light ray 244a and subsequent light rays 246a, 248a, and 250a remain in propagation component 230 and propagates toward first end 232 of propagation component 230 generally in direction 241 as long as the relations in equations (7) and (8) are satisfied. When n260=n220, equations (7) and (8) provide identical ranges of acceptable angles.
Referring to FIG. 5, a solar collector 300 is shown. Solar collector 300 comprises a light directing component 310, a buffer component 320, and a propagation component 330. Solar collector 300 is generally identical to solar collector 100 and solar collector 200. Light directing component 310, in one example, includes at least one holographic element. Light directing component 310, in another example, includes at least one diffraction grating or ruling. Propagation component 330, in one example, includes a refractive media such as a suitable plastic or glass or liquid. Buffer component 320, in one example, includes a refractive media having a lower index of refraction than propagation component 330 such as a plastic material, a glass material, a liquid, or air.
The buffer component 320 of solar collector 300 includes a top portion 322, a bottom portion 324, a first side portion 326, a second side portion 328, and a rear portion 329 which provide a constant interface around the entire propagation component 330 except for a portion 332 located at a first end 302 of solar collector 300. Light directing component 310 is configured to redirect incident solar radiation from at least a first direction 339, denoted by rays 340, such that the solar radiation is coupled into propagation component 330 and generally propagates along direction 342 within propagation component 330 due to at least total internal reflection at the interface between propagation component 330 and buffer component 320. The light propagating in the general direction 342 exits solar collector 300 from portion 332 of propagation component 330 at first end 302 of solar collector 300.
In one embodiment, buffer component 320 provides a constant interface around the entire propagation component 330 such that propagation component 330 is sealed from the exterior of collector 300 and radiation directing component 310 is configured to redirect radiation emanating from an optical source, such as the sun, a laser, a laser diode, or a phosphorescence or fluorescence material. The radiation from the radiation source is coupled into propagation component 330 by radiation directing component 310 and is retained within propagation component 330 by total internal reflection at the interface between propagation component 330 and buffer component 320 such that the radiation is propagated within propagation component 330 in direction 342. The collected radiation at first end 332 of propagation component 330 is generally incident on the interface between buffer component 320 and propagation component 330 at an angle such that the radiation is refracted or transmitted through buffer component 320 and may be subsequently coupled to an output component 340. In one example, an output component 340 is positioned proximate to first end 332 of propagation component 330 through an opening (not shown) in buffer component 320.
In one example the radiation source is a phosphorescence or fluorescence material applied to a lower surface (not shown) of buffer component 320 or on top of a radiation directing component configured to redirect the resultant radiation. As such, the radiation produced from the phosphorescence or fluorescence material is transmitted through the lower portion 324 of buffer component 320 and is either transmitted into propagation component 330 at an angle such that it is retained within propagation component 330 due to total internal reflection or is transmitted through propagation component 330, the upper portion 322 of buffer component 320 and is incident on radiation directing component 310. Radiation directing component 310 is configured to reflect the incident radiation back into upper portion 322 of buffer component 320 at an angle such that the radiation is transmitted into propagation component 330 and retained within propagation component 330 due to total internal reflection.
In another example, wherein propagation component 330 is sealed within buffer component 320. Propagation component 330 includes a phosphorescence or fluorescence material and radiation directing component 310 is configured to pass incident radiation from at least direction 339 such that at least a portion of the incident radiation is transmitted into propagation component 330. The incident radiation excites or otherwise causes the phosphorescence or fluorescence material to emit radiation. The emitted radiation is either propagated within propagation component 330 generally in direction 342 due to total internal reflection or is transmitted out of propagation component 330, through buffer component 320 and is incident on radiation directing component 310. The emitted radiation is redirected or reflected by radiation directing component 310 back through buffer component 320 and into propagation component 330 such that the emitted radiation is propagated within propagation component 330 generally in direction 342 due to total internal reflection. In one variation, radiation directing component 310 is positioned on multiple exterior surfaces of buffer component 320.
Solar collectors 100, 200, and 300 are manufactured in one embodiment from extrudable material such as various plastics. Exemplary extruded plastics include extruded acrylics and extruded polycarbonates available from Bay Plastics Ltd located at Unit H1, High Flatworth, Tyne Tunnel Trading Estate, North Shields, Tyne & Wear, in the United Kingdom. In the case of solar collectors 100, 200, 300 the propagation components 130, 230, and 330 and the buffer components 120, 220, 260, and 320 are extruded separately and then assembled. In one example, the various layers are coupled together with a suitable optical adhesive. In another example, the various layers are coupled together by pressing the layers into contact with each other while the layers are at an elevated temperature to “thermally weld” the various layers together. In an alternative method, propagation component 330 of solar collector 300 is first extruded and then buffer component 320 is extruded over propagation component 330.
Light directing component 110, 210, and 310 in one embodiment is then coupled to the respective assembled buffer components 120, 220, and 320 with a suitable optical adhesive. In another embodiment, light directing component 110, 210, and 310 is formed on a top surface of buffer component 120, 220, and 320. One example of light directing component 110, 210, and 310 being formed on buffer component 120, 220, and 320 is the stamping or pressing of a diffraction grating or ruling pattern in the top surface of buffer component 120, 220, and 320.
In other embodiments of solar collectors 100, 200, and 300, the solar collectors are assembled from cast components, such as cast acrylic, or a combination of cast components and extruded components or from optical components manufactured by various other manufacturing processes. Exemplary cast acrylic components include HESA-GLAS from Notz Plastics AG and available from G-S Plastic Optics located 23 Emmett Street in Rochester, N.Y. 14605.
Once the solar radiation reaches the first end of solar collector 100, solar collector 200 or solar collector 300, the solar radiation exits the respective propagation component 130, 230, 330 and is coupled to an output component 340 as diagrammatically shown in FIG. 6A. Output component 340 is configured to receive the solar radiation exiting propagation component 330 and to transport and/or otherwise utilize the solar radiation. Example output components include energy converting component 342, a second solar collector 344, and an optical transport component 346.
Energy converting component 342 is configured to convert the solar radiation into another form of energy for storage or use. Example energy converting components 342 include any photoelectrical transducer, or any photochemical transducer, or any type of radiation detector. An example photoelectrical transducer is a photovoltaic cell or solar cell. An example photochemical transducer is a synthetic chlorophyll which can absorb the supplied radiation to produce fuels such as oxygen or hydrogen. Example radiation detectors include silicon detectors available from Edmund Industrial Optics located at 101 East Gloucester Pike, in Barrington, N.J./USA 08007.
Second solar collector 344 includes a light directing component generally similar to light directing components 110, 210, 310, a buffer component generally similar to buffer components 120, 220, 260, 320, and a propagation component generally similar to propagation components 130, 230, 330. Second solar collector 344 is configured to receive solar radiation exiting propagation component 330 of solar collector 300 from at least a first direction, such as direction 341 in FIG. 7A and to redirect the solar radiation along at least a second direction, such as direction 343 in FIG. 7A. In one example, the light directing component of solar collector 344 is configured to receive solar radiation from multiple directions corresponding to the multiple directions of totally internally reflected light rays within propagation component 330. Alternatively, second solar collector 344 is abutted to first end 302 of solar collector 300 and is configured to receive solar radiation exiting the propagation component of solar collector 300 from at least a first direction directly into the propagation component of solar collector 344 such that the solar radiation propagates within solar collector 344 along with additional solar radiation being redirected and propagated by solar collector 344.
Optical transport component 346 is configured to transport the solar radiation exiting propagation component 330 to a remote location. Optical transport component 346 operates similar to fiber optics and includes a buffer component, such as buffer component 320, and a propagation component, such as propagation component 330 of solar collector 300.
Referring to FIG. 6B, solar collector 300 in another embodiment is coupled to a frame 348 and is coupled to an output component 340. Frame 348 is coupled to a tracking component 350 which is configured to move and position solar collector 300. Referring to FIG. 6C, solar collector 300 is coupled to output component 340 and both solar collector 300 and output component 340 arc coupled to frame 348. Frame 348 is coupled to a tracking component 350 which is configured to move and position solar collector 300. Tracking component 350 is configured to move solar collector 300 such that solar collector 300 is capable of tracking the sun throughout a given day and various seasons of the year. Tracking component 350 comprises a positioning component 352, such as a motor, and a controller 354, such as a computer. Controller 354 is configured to control positioning component 352 and hence the movement of solar collector 300. In one example controller 354 executes instructions from either software or hardware which provide the preferred position of solar collector 300 for a given time of day and a given time of the year.
Referring to FIGS. 7A-7C, a first example configuration of solar collector 300 is shown wherein solar collector 300 is coupled to solar collector 344 which in turn is coupled to optical transport component 346. Incident solar radiation 360 is redirected by light directing component 310 such that the solar radiation is propagated in propagation component 330 generally in a direction 341. The solar radiation exits propagation component 330 from portion 332 of propagation component 330 and is incident on light directing component 370 of solar collector 344. Light directing component 370 is configured to redirect the solar radiation from propagation component 330 through buffer component 380 and into propagation component 384 such that the solar radiation is propagated within propagation component 384 generally along direction 343.
The solar radiation exits propagation component 384 at portion 386 of propagation component 384 and is coupled into optical transport component 346 through an adapter 381. Adapter 381 includes a propagation component 387 and a buffer component 389. In one example, propagation component 387 and propagation component 384 have approximately the same index of refraction and buffer component 389 and buffer component 380 have approximately the same index of refraction. Adapter 381 is configured to propagate the solar radiation from a first end 383 to a second end 385 by retaining the solar radiation within propagation component 392 due to total internal reflection. Further, in the illustrated embodiment adapter 381 is configured to mate with a generally quadrilateral cross-section of solar collector 344 at first end 383 of adapter 381 and to mate with a generally circular cross-section of a first end 391 of optical transport component 346 at second end 385 of adapter 381. It should be understood that adapter 381 is configured to couple together two components having dissimilar cross sections. Further, adapter 381 may be used in conjunction with couplers 616 and 624 shown in FIGS. 12A and 12B and described below.
Optical transport component 346 includes a propagation component 392 and a buffer component 394. In one example, propagation component 392 and propagation component 387 have the same index of refraction and buffer component 394 and buffer component 389 have the same index of refraction. Optical transport component 346 is configured to propagate the solar radiation to a remote location by retaining the solar radiation within propagation component 392 due to total internal reflection.
Referring to FIG. 7D, solar collector 344 is replaced by solar collector 344′ which operates generally identical to solar collector 344. Solar collector 344′ differs from solar collector 344 in that propagation component 384′, buffer component 380′, and light directing component 370′ are generally cylindrical in shape. As shown in FIG. 7D first end 332 of solar collector 300 has been modified to have a concave extent configured to mate with light directing component 370′ of solar collector 344′. In one embodiment, solar collector 344′ is made from an optical transport component 346 having a generally circular cross-section along its extent and a light directing component 370′ coupled to a portion of buffer component 394 of optical transport component 346.
Referring to FIG. 7E, solar collector 344′ is formed from a circular optical transport component 346 having two light directing components 370a and 370b. Light directing component 370a is configured to receive solar radiation from solar collector 300a propagating in direction 347 and light directing component 370b is configured to receive solar radiation from solar collector 300b propagating in direction 341.
In some applications, the solar collectors of the present invention are used on surfaces of buildings, such as roofs, or exterior walls to collect solar radiation and to provide the solar radiation to an output component or for lighting applications. Referring to FIG. 8, a side, elevational, schematic representation of a plurality of solar collectors 400 affixed to a roof 422 of a building 421 is shown. Solar collectors 400 are generally similar to solar collectors 100, 200, and 300. As stated previously the radiation collected by solar collector 400 is coupled into an output component 340. As illustrated in FIG. 8, solar collectors 400 are coupled through additional solar collectors (not shown) to optical transport components 445a, 445b. Optical transport components 445a, 445b in turn transport the solar energy collected by solar collectors 400 to a remote location, such as an interior 423 of building 421 as shown in FIG. 8. As such, optical transport components 445a, 445b provide the solar radiation for remote lighting applications or for coupling to an output component 340, such as an energy converting component 342. It is therefore possible with the present invention to collect solar radiation at a relatively high temperature environment and to transport that radiation to a relatively lower temperature environment. As such, energy converting component 342 can be supplied with adequate amounts of solar radiation and also be positioned in an environment that correlates to a preferred operating condition of energy converting component 342.
Referring to FIG. 9A, a first embodiment of solar collector 400 is shown. Solar collector 400 is configured as an alternative to conventional shingles, for use on roof 422. Solar collector 400 operates generally identical to solar collectors 100, 200, 300 and includes a light directing component 410, a buffer component 420, and a propagation component 430. Further, solar collector 400 includes an attachment component 440 configured to receive fastening components (not shown), such as nails, screws or staples, to secure solar collector to roof 422 of building 421. Attachment component 440 is made of a material suitable for accepting fastening components and securing solar collector 400 to roof 422 of building 421.
Since solar collector 400 is secured to roof 422, light directing component 410 is configured to receive solar radiation from multiple directions and to redirect the incident radiation such that it is propagated within propagation component 430. Further, light directing component 410 is configured to receive solar radiation corresponding to multiple wavelengths. Solar collector 400 further includes a protective component (not shown) which overlays at least light directing component 410 to protect light directing component 410 from the elements and other potential sources of damage. The protective component is comprised of a material that has good optical transmission properties and is generally weather-resistant. In an alternative embodiment, light directing component 410 is positioned below buffer component 420 to protect light directing component 410 from the elements.
When a plurality of solar collectors 400 are positioned on roof 422, as shown in FIG. 8, a bottom portion 442 of buffer component 420 of a first solar collector overlaps a top portion 444 of attachment component 440 of an adjacent and lower solar collector, similar to how conventional shingles overlap when positioned on roof 422. In one variation of solar collector 400, either top portion 444 of attachment component 440 or bottom portion 442 of buffer component 420 has an adhesive applied thereto to assist in securing adjacent overlapping solar collectors 400 to each other.
In another embodiment of solar collector 400, attachment component 440 is replaced with an attachment component 460. Attachment component 460 includes a first portion 462 to receive light directing component 410, buffer component 420 and propagation component 430 of solar collector 400, the optical component, and a second portion 464 to receive fastening components (not shown) to secure solar collector 400 to roof 422. Portion 462 of attachment component 460 is recessed relative to portion 464 such that light directing component 410 is generally flush with portion 464 of attachment component 460. Lower portion 442 of buffer component 420 is secured to a top surface 466 of attachment component 460 with an adhesive.
In one variation of solar collector 400, attachment component 440 or attachment component 460 are colored to given the appearance of traditional shingles or other roofing or building materials such that the roof appears aesthetically the same as a traditional roof. Further, a top surface 468 of solar collector 400 includes indicia (not shown) to give the appearance of the tabs of traditional shingles.
In another variation of solar collector 400, solar collector 400 is made from one or more flexible materials. As such, solar collector 400 is capable of being distributed as a roll of material that is applied to roof 422 by unrolling the roll on roof 422 to extend along an extent of roof 422, as a first row of “solar sheeting”. The first row of “solar sheeting” is attached to roof 422 with fastening components. Solar collector 400 is then cut to length such that at least one of the ends of solar collector 400 includes a first surface 432 of propagation component 430. An output component 340 (as shown in FIG. 6A), such as energy converting component 342, another solar collector (not shown), or optical transport components 445a and 445b, is then coupled to the end of solar collector 400 including first surface 432. Next, a second row of “solar sheeting” are positioned by unrolling the remaining roll of solar collector 400 such that a portion of the second row overlays the first row and repeating the steps of fastening, trimming and coupling the second row. This operation is repeated for subsequent rows of “solar sheeting”.
In some instances, a row of “solar sheeting” is comprised of two separate sections of solar collectors, such as pieces from two rolls of solar collectors. The two sections of solar collectors may be coupled together by trimming the adjacent ends of each solar collector and either coupling the two sections together with an optical adhesive or coupling each end of the adjacent ends to an intermediate optical coupler, such as an optical transport component. As shown in FIG. 14, two sections of solar collector 400, sections 400a and 400b, are corrected together with an optical transport component 480. Sections 400a and 400b, each include a respective propagation component 430a and 430b and a respective buffer component 420a and 420b. Optical transport component 480 includes a buffer component 482 and a propagation component 484 which is configured to receive light ray 490 from propagation component 430a into propagation component 484 and to supply the solar radiation to propagation component 430b in solar collector 400b. In one example an optical adhesive is positioned between solar collector 400a and optical transport component 480 and between solar collector 400b and optical transport 480 to couple solar collector 400a and 400b to optical transport 480. In another example, optical transport 480 includes detents (not shown) on surfaces 492 and 494 of first elongated end 486 and on surfaces 496 and 498 of second elongated and 488. The detents are sized and configured to couple solar collectors 400a and 400b to optical transport 480.
Referring to FIGS. 10 and 11, a solar collector 500 is shown. Solar collector 500 includes a plurality of light directing components 510, a first buffer component 520, a propagation component 530, and a second buffer component 540. Light directing components 510 are positioned within first buffer component 520 and oriented at an angle to top surface 522 of first buffer component 520. A lower portion 512 of light directing components 510 is spaced apart from a lower portion 525 of first buffer component 520 such that light directing components 510 do not touch propagation component 530. In an alternate embodiment solar collector 500 is similar to solar collector 100 and does not include a second buffer component 560.
Solar collector 500 operates in a similar manner to solar collectors 100, 200, 300, and 400 of the present invention. Solar radiation, as represented by light ray 550, enters first buffer component 520 from at least a first direction 539 through top surface 522 and is redirected by light directing component 510 along at least a second direction 543 as light ray 552a. Light ray 552a is incident on interface 524 between first buffer component 520 and propagation component 530 at an angle θ552a and is refracted into propagation component 530 at an angle θ554a1. Light ray 554a propagates through propagation component 530 and strikes second buffer component 560 at an angle θ554a2 at interface 526. The refractive indexes of first buffer component 520, propagation component 530, and second buffer component 560 as well as the angle of light ray 552a directed by light directing component 510 are chosen such that angle θ554a2 and subsequent angles (θ556a2, θ558a2 . . . ) satisfy the requirements generally expressed in equations 3 and 4, thereby retaining light rays 554a, 556a, 558a and subsequent rays within propagation component 530 by total internal reflection and propagated generally in direction 541 toward first end 532. Alternatively interface 526 includes a reflection coating to reflect light rays 554a and 554 into propagation component 530. In yet further alternative embodiments, surfaces 521, 531, 561 of first buffer component 520, propagation component 530, and second buffer component 560, respectively, include a reflection coating.
In the illustrated embodiment, light directing components 510 are shown generally planar. In alternative embodiments the light directing components are concave ill shape. The concave shape of the light directing components provides an additional mechanism by which incident solar radiation from multiple directions can be coupled into the propagation component by the light directing components.
Referring to FIGS. 12a and 12b multiple optical transport components 346, such as optical transport components 346a and 346b may be coupled together to form an optical connector 600. Optical transport components 346a and 346b each include a respective propagation component 384a and 384b and buffer components 380a and 380b. Optical connector 600 is shown as a T-connector, however, optical transport components 346a and 346b may be coupled at a variety of angles. Optical connector 600 is configured to couple radiation propagating within propagation component 384b of optical transport component 384b generally in direction 602 into propagation component 384a of optical transport component 346a such that the coupled radiation is retained within propagation component 384a and is propagated generally in direction 604 or in direction 606 or in both direction 604 and direction 606 depending on the characteristics of light directing component 610.
Referring to FIG. 12b, light directing component 610 is coupled to, formed on, or otherwise positioned on surface 612 of optical transport component 346a. Light directing component 610 is further coupled to, or formed on, or positioned adjacent to a first end 614 of optical transport component 346b. First end 614 is shown as being configured to match the contour of surface 612 of optical transport component 346a. However, first end 614 maybe flat, concave, convex, or additional configurations. In one example, light directing component 610 includes a holographic element and is coupled to surface 612 of optical transport component 346a and first end 614 of optical transport component 346b with an optical adhesive. In another example, optical transport component 346a, optical transport component 346b and light directing component 610 are formed as an integral optical connector.
In a further example of optical connector 600, optical transport component 346a and optical transport component 346b are further secured to light directing component 610 with a coupler 616. Coupler 616 includes a first portion 618 and a second portion 620 which are configured to wrap around surface 612 of optical transport component 346a and to be adhered to a surface 622 of optical transport component 346b. 
As shown in FIG. 12b, an additional coupler 624 is shown. Coupler 624 includes a cylindrical body 626 having an interior surface 628 sized to receive surface 612 of optical transport component 346a and a similar surface of an additional optical transport component (not shown). Optical transport component 346a may be secured to coupler 624 and the adjacent optical transport component (not shown) with a suitable optical adhesive.
In yet another example of optical connector 600, optical transport component 346a and optical transport component 346b are secured to a fixture or frame (not shown) and are positioned such that first end 614 of optical transport component 346b is positioned proximate to surface 612 of optical transport component 346a. Further, light directing component 610 is either positioned in the space between optical transport component 346a and optical transport component 346b, formed on first end 614 of optical transport component 346b, formed on surface 612 of optical transport component 346a, coupled to first end 614 of optical transport component 346b, or coupled to surface 612 of optical transport component 346a. 
It is possible, therefore with optical connectors 600, to have a plurality of optical transport components 346, such as optical transport component 346b, each having a first end 614 positioned generally radially to a main optical transport component 346, such as optical transport component 346a. Each of the radially placed optical transport components 346b are optically coupled to main optical transport component 346a through a light directing component, such as light directing component 610.
As such with optical connectors 600 it is possible to create a network of optical transport components 346. Referring to FIG. 13, an optical network 700 is shown. Optical network 700 includes plurality of solar collectors 702a-d, each configured to collect incident radiation and to couple the collected radiation into an optical transport component, such as optical transport components 704a-d. Each optical transport component 704a-d is configured to transport the collected radiation. As shown in FIG. 13, optical transport component 704a and 704b transport the radiation collected by solar collectors 702a and 702b, respectively, generally in a direction 706 while optical transport component 704c and 704d transport the radiation collected by solar collectors 702c and 702d, respectively, generally in a direction 708.
Optical transport components 704a-d, each is coupled to a main optical transport component 704e at connections 710a-d. Connections 710a-d are configured to couple the radiation transported by optical transport component 704a-d into optical transport component 704e such that the radiation is propagated within optical transport component 704e in either direction 712 or direction 714 or in both direction 712 and direction 714. Each of connections 710a-d includes a light directing component (not shown) whose characteristics determines the direction of travel of the radiation from the corresponding optical transport component 704a-d within optical transport component 704e, either direction 712, direction 714 or a combination of direction 712 and 714. In one example, connections 710a-d include optical connectors 600 similar to the optical connectors illustrated in FIGS. 12A and 12B such that optical transport component 704e is comprised of several segments interconnected with optical connectors 600. In another example, connections 710a-d include optical connectors 600 as discussed above wherein optical transport component 704e is a main optical transport component and optical transport components 704a-d are radially positioned optical transport components.
Once the radiation transported by optical transport components 704a-d is coupled into optical transport component 704e, it is delivered either to another connection, such as connection 710e or to an end 716 of optical transport component 704e. As illustrated in FIG. 13 connection 710e couples the radiation propagating in optical transport component 704e in direction 712 into an optical transport component 704f. The radiation coupled into optical transport component 704f is either propagated generally in direction 706, generally in direction 708, or in generally in both directions 706 and 708 depending on the characteristics of the light directing component corresponding to connection 710e. The radiation coupled into optical transport component 704f is propagated to either a first end 718 or a second end 720 of optical transport component 704f. The radiation propagated to end 716 of optical transport component 704e or first end 718 or second end 720 of optical transport component 704f is then supplied to an output component, such as output component 340 or for lighting applications.
Optical network 700 is shown in FIG. 13 for use in the collection of solar radiation. However, it should be understood that additional types of optical networks are envisioned. For instance, optical connectors 600 can be configured to couple multiple optical fibers together in an optical network. As such, optical connectors 600 are capable of use to couple optical signals, such as data signals, from a first fiber optic cable, such as optical transport component 346b, into a second fiber optic cable, such as optical transport component 346a. 
In one example, light directing component 610 is configured to redirect radiation propagating in optical transport component 346b having a first wavelength, such as 632.8 nanometers, generally along direction 604 in optical transport component 346a and radiation of a second wavelength different than 632.8 nanometers generally along direction 606 in optical transport component 346a. As such, based on the wavelength of radiation propagating within optical transport component 346b light directing component 610 acts as an optical switch to send radiation of a first wavelength along first direction 604 of optical transport component 346a or a first optical circuit and radiation of a second wavelength along second direction 606 of optical transport component 346a or a second optical circuit. Further, if radiation containing both the first and the second wavelengths is propagating within optical transport component 346b as first and second data signals, light directing component 610 acts as an optical separator or filter by sending radiation of a first wavelength, the first data signal, along first direction 604 of optical transport component 346a and radiation of a second wavelength, the second data signal, along second direction 606 of optical transport component 346a. Although the above example discusses the use of optical connector 600 as an optical switch or optical separator for two distinct wavelengths, it is contemplated that optical connector 600 can be used as an optical connector, an optical switch, or an optical separator for one, two, three or more distinct wavelengths.
In another example, optical transport component 346b is replaced with an optical source, such as a laser, a laser diode, a light-emitting diode, photochemical radiation sources such as a phosphorescence or fluorescence material, or other radiation producing component. As such, the radiation produced by the optical source is coupled into optical transport component 346a through light directing component 610.
Referring now to FIGS. 15a and 15b, exemplary photocollectors 800 and 802 (e.g., solar radiation collectors) are shown. It is initially noted that the only difference between photocollectors 800 and 802 is the configuration of the light directing components within the first layer of the assembly, which is a buffer component region 820. While photocollector 800 includes a plurality of louvers 810 as its light directing component mechanism, photocollector 802 includes a diffraction grating 812 as its light directing component, such as shown and described with respect to light directing component 310 of FIG. 1 above. Operationally, the diffraction grating 812 is configured to cause a loss of energy to be imparted on the light rays as they are deflected within the collector (i.e., approximately a 30% drop in power is possible within the grating apparatus), while no such energy loss is caused within the louver mechanism 810. In addition to the buffer region 820, both photocollectors 800 and 802 also include a propagation component layer 830 and a collector region 840.
The propagation component layer 830 includes a plurality of windows 836 that are configured to allow the propagated light rays 801 to enter the collector region 840. In turn, the collector region 840 includes a plurality of regions 845 having transparent refractive index material where the refractive index increases in a smooth fashion and then decreases to a magnitude equal in refractive index to the beginning of the region 845. The photocollectors also include a light directing component 870 (FIG. 15c) and a photocollector 844 including a buffer component 880 and a propagation component 882. Finally, the photocollectors 800 and 802 also include an optical transport 846 that is configured to transport the solar radiation exiting the collectors to a remote location. As shown in FIG. 15c, optical transport 846 operates similar to fiber optics and includes a buffer component 894 and a propagation component 892, such as discussed in detail above with reference to optical transport 346. In other words, incident radiation (e.g., solar radiation) is redirected by the light directing component (e.g., louvers 810 or diffraction grating 812) such that the radiation is propagated in the propagation component layer 830 generally in a direction 841. The radiation exits propagation component layer 830 through one of the plurality of windows 836 and enters the collector region 840. Once the radiation reaches portion 832 of the collector region 840, it is incident on light directing component 870 of photocollector 844. The light directing component 870 is configured to redirect the radiation from the collector region 840 through the buffer component 880 and the propagation component 882 of the photocollector 844 such that the radiation is propagated within the propagation component 882 of photocollector 844 generally along direction 843.
The radiation exits the propagation component 882 and is provided into the optical transport component 846, which is configured to propagate the radiation to a remote location by retaining the radiation within propagation component 892 due to total internal reflection (“TIR”). To accomplish this, the circumference of the propagation component 892 is chosen so that it is large enough to completely circumscribe the square inner propagation component 882 of photocollector 844, and particularly such that the collected light energy is completely transferred to the propagation component region 892 with no loss of energy through suitable refractive matching and optical coupling.
A detailed explanation of how solar collector 800 operates is now provided with reference to FIG. 16. According to this exemplary embodiment, vertical light rays 801 (solar photons) enter buffer component layer 820 from above the collector 800 and are deflected from the vertical by the set of light directing components or louvers 810. The light directing components 810 deflect the rays towards the propagation component layer 830 at an angle. The louvers are constructed of material with a refractive index less than the other material surrounding it in the buffer component layer 820. Examples of various materials from which the louvers may be constructed (as well as the other materials and components of the present photocollectors) are shown in Table 1 above. For example, if the refractive index of the louver material has an index of refraction of 1.0 (e.g., air) and the surrounding material has an index of refraction of 1.5, the critical angle of incidence between the two materials at the contact interface 835 is 41.8 degrees. If the light rays strike a louver surface tilted at 50 degrees from horizontal, the angle of incidence of the vertical light ray at the louver interface is 50 degrees and greater than the critical angle of 41.8 degrees. This ray is totally reflected at the louver surface with 100% conservation of energy. The angle of incidence at the interface 835 is 85 degrees. In a similar fashion, a 45-degree louver tilt provides a TIR reflected ray horizontal to the collector surface, and a 60-degree louver tilt provides a 60-degree angle of incidence at interface 835. An adequate operating angle of incidence at the interface 835 is expected to lie between 60 and 80 degrees.
The louvers are designed to interact with the totality of the vertical light rays 801 reaching the surface of buffer region 820. As such, as the tilt of the louvers change, the space between them needs to be adjusted to interact with all rays 801. The rays 801 hitting the upper half of straight louvers 810 will by geometric principles hit the backside of adjacent louvers. A remedy for this circumstance is to impart a slight concavity 803 to the upper half of the louvers so that the light hitting the upper half of a particular louver 810 will reach interface 835 and not interact with either an adjacent louver or the louver that a ray hit initially. The operation of such concavity is shown in further detail in FIG. 17. The incident angle at the surface of interface 835 will decrease depending upon this upper louver concavity but will not result in a substantial diminution of operation, since the range of incidence angle has an operating range of 15 degrees or more.
When the rays hit the interface 835 of the propagation component layer 830, some diffraction and reflection will occur since the refractive index of layer 830 is greater than the refractive index of layer 820 (see for instance the light rays labeled as reference numeral 801a). In certain exemplary embodiments, approximately 20% reflection will be lost due to the reflected light. It should be understood and appreciated herein, however, that this loss can be optimized by changing the angle of incidence of the light ray. For example, assuming an interface consisting of a material with a refractive index of 1.0 (air) and a subsequent material to which the light is directed to has a refractive index of 2.0 (the critical angle of incidence for this system interface is 30 degrees), the average reflection coefficient of light for an angle of incidence of 0 degrees (perpendicular to the plane of incidence) is approximately 11%. That is, 89% is transmitted and 11% is reflected back to the light source. As the angle of incidence is increased at 835, the amount of reflected light increases according to the Fresnel equations of light behavior such that approximately 20% of light is reflected up to approximately a 70 degree angle of incidence at interface 835. In certain exemplary embodiments, the index of refraction for the buffer component layer is from about 1.0 to about 1.3 and the index of refraction for the propagation component layer 830 is from about 1.5 to about 2.0. It is further anticipated that a gradual transition from one refractive index to another can be achieved at interface 835, as opposed to a discrete interfacial barrier, such that no energy loss will occur as light travels from region 820 to region 830.
Once rays 801 enter the propagation component layer 830, no loss is expected to occur due to the operation of the rays within the second layer. Rays 801 will continue to exhibit total internal reflection off interface 835 and propagation component structures 837 until they enter one of the plurality of windows 836 whereupon the rays will enter the collector region 840. The positive slope of the upper surface of reflecting element 837 will impart an increase in the incident angle of ray 801 as it travels towards interface 835 and after it has reflected off the component 837. This positive slope will result in the angle of incidence of ray 801 to be greater than the critical angle necessary to provide total internal reflection at the 835 interface. Generally, the refractive index difference between component 837 and the surrounding material comprising layer 830 is such that total internal reflection will occur on all surfaces of the component 837 at the incidence angles experienced by ray 801 as it interacts with component 837. The spaces between components 837 (so-called “windows” 836) can be adjusted such that overlapping configurations can occur. While the general configuration of the device would remain the same, it has been found that increasing the spacing between the windows may be beneficial in terms of the angles in the system and the refractive index materials employed within the system.
Rays 801 will continue generally to the right as indicated by arrow 847, entering the variable refractive regions 845 of transparent refractive index material. Regions 845 are characterized by smooth increases in refractive index starting at or after the leftmost point of component 837 until a peak is reached upon which the refractive index returns to the refractive index existing at the front of region 845, where the light 801 initially enters 845. This region is where entering light has a possibility of entering the window area from below and exiting the photocollector. To prohibit this circumstance, the incoming ray is bent generally towards the center of collector region 840 such that it misses entering the window region from below since the material through which it is traveling is increasing in refractive index. More particularly, if each medium has a different refractive index, as light passes from one transparent medium to another, it can change speed and bend. How much this happens depends on the refractive index of the mediums and the angle between the light ray and the line perpendicular (normal) to the surface separating the two mediums (medium/medium interface). The angle between the light ray and the normal as it leaves a medium is called the angle of incidence. The angle between the light ray and the normal as it enters a medium is called the angle of refraction. Refractive indexes can be found experimentally by providing two media optically coupled to each other, directing light into the first medium, through the interface, and into the second medium and then measuring the bending of light at the interface, thereby defining the angle of incidence and angle of refraction. Using Snell's Law (eq. 1) the refractive index of one medium can be related to another medium's refractive index and calculated, once the angle of refraction and angle of incidence are determined.
Regions 845 use gradual changes in refractive index to effect light bending. When traveling through regions 845, the light does not encounter a discrete interface separating abrupt changes in refractive index, rather it gradually alters speed, thereby not experiencing reflective loss at a defined interface and conserving ray energy. As it proceeds to exit region 845 (finishes passing by and below the window area) it bends away from the central region of 840 since it travels through material that is decreasing in refractive index. Light rays sufficiently in front of the window area would reflect off the horizontal surface of component 837 and then proceed generally downward to the right along arrow 847 and miss the window area. For light headed towards the window area and within 845, a gradual transition of a refractive index value of 1.5 to a refractive index of 2.0 would yield an approximate 10-degree shift towards the central region of collector region 840 by the end of the window (the beginning of the horizontal portion of component 837). Upon exiting region 845, the light ray would return to the same direction it was traveling prior to entering the component region 845 and continue TIR (total internal reflection) through component 840. Light not heading towards a window area would experience the transition of ray directional change when traveling through the component 837 with no loss of operation. The gradual change in refractive index permits a change in ray direction without loss of power with directional change as occurs at discrete interfacial boundaries with abrupt refractive index changes engendering reflective and refractive phenomena to occur. The horizontal size of the window 836, is dependent upon the geometrical shape (e.g., triangular, hexagonal, pentagonal, etc.) and the spacing of the components 837 and may be modified to suit refractive indexes and angular specifications employed, however the general features and operation of the device operation will remain the same.
This process is then repeated until all of the light rays arrive at the rightmost region of the collector and enter the optical transport component 846. At the rightmost region of the collector, the same process also directs the light rays to the corner of the plane of the surface device as an effective collected amount of light energy in a confined space of arbitrary size and area. It should be understood and appreciated herein that optimizing the distances between the propagation component structures within the second layer in the horizontal direction (thereby altering the window region size and orientation) will determine where the modified refractive index region will exist in size and intensity.
Although the invention has been described in detail with reference to certain illustrated embodiments, variations and modifications exist within the scope and spirit of the present invention as described and defined in the following claims.

## Claims

1. A collector for propagating incident radiation to a remote location, comprising:
a radiation directing component configured to redirect the incident electromagnetic radiation;
a buffer component coupled to the radiation directing component, the buffer component configured to transport the electromagnetic radiation redirected by the radiation directing component; and
a propagation component coupled to the buffer component and configured to propagate the electromagnetic radiation generally in a first direction toward a first end of the propagation component by at least total internal reflection, the propagation component including a plurality of spaced apart regions through which the electromagnetic radiation would pass as it is propagated towards the first end, an index of refraction of each of the plurality of spaced apart regions generally increases from a leading edge of the region to a peak value and then decreases towards a trailing edge of the region, the radiation directing component being positioned such that the electromagnetic radiation incident on the collector which is received into the propagation component is incident from a direction generally not parallel with the first direction of the propagation component.

2. The collector of claim 1, wherein each of the plurality of regions has a first index of refraction at the leading edge of the region and a second index of refraction at the trailing edge of the region.

3. The collector of claim 2, wherein the first index of refraction is equal to the second index of refraction.

4. The collector of claim 2, wherein the peak value of the region is about 133 percent of first index of refraction.

5. The collector of claim 2, wherein the peak value of the region is about 133 percent of second index of refraction.

6. The collector of claim 2, wherein the index of refraction gradually transitions from the first index of refraction to the peak value.

7. The collector of claim 6, wherein the first index of refraction is about 1.5 and the peak value is about 2.0.

8. The collector of claim 2, wherein the index of refraction gradually transitions from the peak value to the second index of refraction.

9. The collector of claim 8, wherein the peak value is about 2.0 and the second index of refraction is about 1.5.

10. The collector of claim 1, wherein the radiation directing component is configured to receive and redirect electromagnetic radiation of at least two wavelength bands.

11. The collector of claim 1, wherein the radiation directing component is configured to receive and redirect electromagnetic radiation from at least one additional direction.

12. The collector of claim 1, wherein the radiation directing component includes a holographic element.

13. The collector of claim 12, wherein the radiation directing component includes a diffraction grating.

14. The collector of claim 1, wherein the propagation component includes a plurality of spaced apart reflective components and wherein each of the plurality of regions is located to overlap a space between adjacent reflective components.

15. The collector of claim 14, wherein the electromagnetic radiation enters a collection region of the propagation components through the space between adjacent reflective components, the collection region including the plurality of spaced apart regions.

16. The collector of claim 14, wherein a portion of the electromagnetic radiation exiting a first region of the plurality of spaced apart regions is reflected by a lower surface of a first reflective component.

17. The collector of claim 14, wherein a portion of the electromagnetic radiation entering a first region of the plurality of spaced apart regions has been reflected by a lower surface of a first reflective component.

18. The collector of claim 2, wherein the first index of refraction is about 1.5 and the peak value is about 2.0.

19. The collector of claim 18, wherein the radiation directing component includes a holographic element.

20. The collector of claim 18, wherein the radiation directing component includes a diffraction grating.