Abstract:
A light collecting and disseminating apparatus is provided for use in harvesting sunlight from the exterior of a man-made structure, and providing light to the inside of the structure, via an opto-mechanical joint where sunlight would not normally be available. The internal arrangement of the collector allows for improved optical accuracy and performance over prior efforts. The apparatus is also characterized as possessing a low profile so as not to alter the appearance of buildings furnished with the invention. Further, light can be collected from any orientation and redirected through the opto-mechanical joint to a stationary light receiving port independent of the orientation of the collectors.

Description:
[0001]    This application claims the benefit of priority to U.S. provisional application having Ser. No. 61/541,305 filed on Sep. 30, 2011, which is incorporated by reference herein in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The field of the invention is light redirection technologies. Background 
         [0003]    Core daylight illumination apparatus systems for buildings are intended to collect, concentrate and direct sunlight from the exterior of the building to internal workspaces for the purposes of replacing a portion of the normally required electrically powered lighting and of improving lighting quality within those workspaces. Widespread use of such systems in commercial workspaces could significantly reduce energy consumption and greenhouse gas emissions. To foster widespread usage, the building core daylight illumination systems must be cost effective, robust, and compatible with common commercial building design and construction practices. 
         [0004]    Previous work on building daylight illumination has not been successful for a number of reasons. Passive daylighting efforts including skylights, vertical light pipes, and other methods of directing non-concentrated or untracked sunlight fail to meet commercial illumination standards over a practical area or during a reasonable percentage of the year and do not provide significant power savings. European Patent application no. 1174658, entitled “Light Carrier System for Natural Light”, by Guzzini, discloses a basic apparatus which collects lights and passes it to the interior of the building through a diffuser. U.S. Pat. No. 6,299,317, “Method and apparatus for a passive solar day lighting apparatus system” by Ravi Gorthala has a Fresnel component, but a “passive” system of light transportation into the building. The collected light would not, therefore, be expected to travel efficiently any distance once inside the building envelope. Control of light distribution is also problematic due to the wide range of angles of light entering the building. 
         [0005]    Previous active daylighting, herein referred to as “sunlighting”, efforts also have significant limitations that affect system cost or life cycle. Designs that include an optical fiber mounted such that it moves with the tracking optics are limited by the resistance caused by the bulky array of moving fiber. Accurate tracking in those cases is costly to provide. One such patent is U.S. Pat. No. 7,295,372 to Parans Daylight discloses a system involving a convex and concave lens to focus sunlight onto transmitting fibers. U.S. Pat. No. 7,813,061, also to Parans Daylight, discloses light focusing lenses which are mobile via ball joints and mobile frames that move independently to change the direction of the lenses. The light collecting element and optical fibers receiving the collected light must also move with the apparatus, which creates problems in keeping the light collecting element aligned to collect sunlight efficiently, and leads to lost light as the optical fiber flexes. 
         [0006]    Generally, designs that utilize long optical fibers from the collector to the lighting fixture are further limited by the properties of the optical fiber over long distances, which distances cause significant light losses due to bulk absorption and noticeable color spectrum shifts. 
         [0007]    Although there are several patents and patent publications pertaining to the concept of concentrating sunlight, or suggesting moving to track the sun, no solutions are offered for a whole apparatus system to make sunlight illumination work in a real context. U.S. Pat. No. 5,169,456 discloses the mechanical aspect of a weather protected “two-axis solar collector mechanism”. No contemplation is made of the necessary optical components of this mechanism, apart from the prediction that a Fresnel lens could be used. 
         [0008]    Externally mounted lighting systems have been provided in Vancouver, Canada, using adaptive butterfly arrays of mirrors (United States Patent Publication 20100254010 and U.S. Pat. No. 8,000,014) and parabolic mirrors. Such systems have been able to deliver adequate luminous flux to the interior of the buildings they serve, but the physical aspects of these building “add-ons” are considerable, as they project up to four feet from the buildings&#39; original exterior wall. 
         [0009]    These and all other extrinsic materials discussed herein are incorporated by reference in their entirety. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply. 
         [0010]    The related art discloses solutions that have cost and performance issues related to relying on optical fiber to transport light over long distances, requiring high tracking accuracy required to minimize fiber diameter, and having reduced tracking mechanism accuracy limitations when needing to flex fiber. Thus, an improved manifestation of a building core sunlight illumination apparatus system that is more effective in terms of total cost per delivered lumen-hour, quality of delivered light, life cycle and suitability to inclusion in new commercial building construction or renovation is needed. 
         [0011]    Unless the context dictates the contrary, all ranges set forth herein should be interpreted as being inclusive of their endpoints, and open-ended ranges should be interpreted to include commercially practical values. Similarly, all lists of values should be considered as inclusive of intermediate values unless the context indicates the contrary. 
       SUMMARY OF THE INVENTION 
       [0012]    The inventive subject matter provides apparatus, systems and methods in which one can construct an opto-mechanical joint that redirects light from a rotatable concentrating element to a fixed location. One aspect of the inventive subject matter includes a joint assembly comprising a light concentrating element mounted on a rotatable frame assembly. The concentrating element can be rotated about an azimuth axis or tilted around an altitude axis to ensure the concentrating element tracks a light source, the sun for example. The concentrating element can include a lens or non-imaging device that concentrates or converges light toward a fixed location. The joint assembly can further include a series of reflective surfaces that redirect the converging light to a fixed location relative to the axes regardless of the orientation of the concentrating element. In some embodiments, a light receiving port (e.g., a waveguide, an optic fiber, etc.) can be positioned at the fixed location to collect the incident converging light. The fixed location can be positioned at a non-focal point of the converging light to reduce hot spots. 
         [0013]    Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0014]      FIG. 1  presents a prior art schematic, fragmented, side elevation view of a 3-story portion of a building having prior art building core sunlight illumination system. 
           [0015]      FIG. 1A  illustrates a cross-sectioned side elevation of the disclosed building core sunlight illumination system. Also shown are an integrated sunshade and sections of curtain wall. 
           [0016]      FIG. 2  illustrates an embodiment of a concentration panel. 
           [0017]      FIG. 2A  presents the concentration panel of  FIG. 2  with the mounting frame removed to show the enclosure interior details. 
           [0018]      FIG. 2B  presents a bottom view of the concentration panel of  FIG. 2  depicting the desiccant plug and electrical box location. 
           [0019]      FIG. 3  illustrates a populated mounting frame. 
           [0020]      FIG. 3A  presents the populated mounting frame of  FIG. 3  where the stationary optical manifold is shown fragmented. 
           [0021]      FIG. 4  illustrates a lower variant of a collector assembly. 
           [0022]      FIG. 4A  presents a side view of the collector assembly of  FIG. 4  with chassis removed from view. 
           [0023]      FIG. 4B  presents a detail view of a lower portion of the collector assembly of  FIG. 4 . 
           [0024]      FIG. 4C  presents a detail rear view of a lower portion of the collector assembly of  FIG. 4 . 
           [0025]      FIG. 5  illustrates a front and rear view of a single optical frame. 
           [0026]      FIG. 5A  presents a more detailed front view of a concentrating element in the single optical frame of  FIG. 5 . 
           [0027]      FIG. 5B  presents a more detailed view illustrating an optical joint behind the concentrating element in the single optical frame of  FIG. 5 . 
           [0028]      FIG. 6  illustrates a rear view the stationary optical manifold where the stationary optical manifold is shown with several optical fibers. 
           [0029]      FIG. 7  illustrates a rear detailed view of the collimator. 
           [0030]      FIG. 7A  presents a side cut view the light path from the stationary optical manifold through the collimator shown in  FIG. 7 . 
           [0031]      FIG. 8  illustrates a cut-away view of a building core sunlight illumination system. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    One should appreciate that the disclosed techniques provide many advantageous technical effects including routing natural light from an exterior portion of a structure to an interior portion of the structure. More specifically, the disclosed subject matter provides the technical affect of routing light along an optical path through an opto-mechanical joint to a fixed point regardless of the incident orientation of the light. 
         [0033]    The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed. 
         [0034]    As used herein, and unless the context dictates otherwise, the term “coupled with” and “coupled to” are intended to include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements). 
         [0035]    There is provided a core building sunlighting apparatus, an example of which is shown in  FIG. 1A . The building core daylight illumination apparatus system comprises a concentrating panel  60  which collects, concentrates and re-collimates sunlight, and a light guide  65  which provides a reflective channel by which the sunlight is transmitted into the building core. The two components are typically connected by a transition funnel  70 . 
         [0036]    The depicted embodiment shows the concentrating panel  60  mounted in typical unified curtain wall  75  and integrated sunshade  80 , although other mounting configurations are possible. 
         [0037]    For comparison, prior art concentration panels or canopies  12 ,  14 , and  16  is shown in  FIG. 1  as part of a multi-storey building  10 . Each one of concentration panels collects and redirects solar light into a corresponding light guide or sunlight distributors  30 ,  32 , and  34 . Note the bulkiness of the apparatus and how it alters the line of the building exterior. 
         [0038]      FIG. 2  depicts a concentration panel which is a sealed, autonomously powered and controlled assembly that is able to be mounted on the outside of buildings, incorporated within the building envelope or mounted independently such as for a sun shade. Contained within or attached to the enclosure  85  are one or more collector assemblies  90 , a stationary optical manifold (not shown), a collimator (not shown), a photovoltaic panel  95 , the electronic controls printed circuit assembly (PCA) and a mounting frame underlying the assemblies. 
         [0039]    The enclosure  85  can include an air-tight box constructed of sheet aluminum or other material on the rear and four side faces, and having a front glass panel  100  providing the front face. The front glass panel  100  can include a glass and vinyl lamination specified for maximum transmission of visible light and filtration of ultraviolet light. The front glass panel  100  is typically bonded to the enclosure  85  with glazing tape and silicone sealant per building construction specifications for structural strength and seal integrity. 
         [0040]    A 1″×1″ glazing fin  105  can extend around the side faces of the enclosure  85  at a position such that the concentration panel as shown generally in  FIG. 2  can be easily mounted in the glazing pocket of common unitized curtain wall building systems. 
         [0041]    Within enclosure  85  as shown in  FIG. 2A , there can be a desiccant tube  110  extending from a threaded port on the bottom face of the enclosure  85  into the interior of the enclosure  85 . The pipe can be filled with a granular desiccant, which may be replaced onsite during routine maintenance in order to eliminate condensation within the enclosure. 
         [0042]    Also shown is a pass-through printed circuit board (PCB)  115  which provides a sealed connection between electronic components mounted inside the enclosure  85  and the electronic controls mounted outside. 
         [0043]    The port of the desiccant tube  110 , seen in  FIG. 2B , is sealed with a threaded plug  120  that has an incorporated membrane vent  125 . The enclosure is thus able to breathe through the desiccant such that, within the enclosure  85 , pressure equilibrium with atmosphere is maintained while internal moisture content is controlled. 
         [0044]    Flashing details, ridgelines or surface features around the enclosure  85  may be incorporated into concentration panel ensure proper water drainage and allow for multi-unit sealing similar in appearance to current unitized curtain wall with structural silicone glazing. 
         [0045]    The rear glass panel  130  seen in  FIG. 2B , is where the output sunlight is ported out of the concentration panel. Rear glass panel  130  is specified for maximum light transmission and includes an anti-reflection coating, and can be bonded to the enclosure  85  with glazing tape and silicone sealant for seal integrity. 
         [0046]    The electronics controls PCA can be connected to the pass-through PCB  115  on the outside of the enclosure  85  and covered with a removable electronics cover  135  and electronics gasket  140  for onsite access. 
         [0047]      FIGS. 3 and 3A  depict a populated mounting frame  145 . The mounting frame  145  has attached to it four collector assemblies  90  in a 2×2 array, the stationary optical manifold (not shown) and the collimator  155  at the read of mounting frame  145 . Once populated, the mounting frame  145  is secured within the enclosure  85 . One should appreciate that the number of collector assemblies  90  coupled to mounting frame  145  can be varied according to a desired implementation or deployment. Collector assemblies  90  can be arranged according to other arrays including 1×1, 1×2, 2×1, or other N×M array where N=M or N≠M. 
         [0048]    In  FIG. 4 , an exemplary single collector assembly  90  is pictured, which includes all optical and mechanical elements required for the tracking of the sun and the collection and concentration of sunlight. The collector assembly  90  consists of a chassis  160  upon which is mounted a linear array of optical frames  165 , an altitude platform  175 , fiber holders  180 , as well as geared drive mechanisms, rotary encoders, and stepper motors for both altitude and azimuth axes. 
         [0049]      FIG. 4A  depicts the biaxially-mobile mechanical assembly which supports and drives the arrayed optical frames  165 . The upper and lower pivot pins  185 ,  190  of each optical frame  165  are mounted in bushings in the chassis such that they can pivot freely and in parallel about their azimuth axes. On each optical frame  165  an altitude frame  170  is attached to each lens holder  195  with pins and bushings such that all the lens holders  195  in the optical frame  165  are linked in a multiple parallelogram four bar mechanism arrangement. The movement of the altitude frame up or down causes all the lens holders  195  to move simultaneously and in parallel about their altitude axes. 
         [0050]    In  FIG. 4B , linkage arms  200  are attached to the azimuth frames and are in turn connected by pin and bushings to a common linkage bar  205  in a multiple parallelogram four bar mechanism arrangement. The movement of the azimuth frames  210  about their azimuth axes is thus constrained to be simultaneous and parallel. 
         [0051]    A detailed drawing of possible drive assemblies for both axes is shown in  FIG. 4C . The optical frames  165  are both rotated about their azimuth axes and held in position by a worm gear set, with the worm gear  215  being mounted on the pivot pin of one of the optical frames  165  and the worm being mounted on the azimuth drive shaft  220 . A stepper motor  225  is mounted on the chassis and linked by a flexible coupling to the azimuth drive shaft  220 . 
         [0052]    The altitude frames  170  of each optical frame  165  are supported on the flat altitude platform  175 . A roller bearing on each altitude frame  170  is the contact point with the altitude platform  175 . The roller bearing sits freely on the altitude platform  175  and is free to translate in any direction. By moving the altitude platform  175  up or down, all altitude frames  170  are moved simultaneously and in parallel, and thus all lens holders  195  are similarly moved simultaneously and in parallel about their altitude axes. The altitude platform  175  is indexed up and down via a linear slide mechanism  230  that is driven by two lead screws  235  which are in turn driven by a worm gear sets with the worm gear mounted on the two lead screws and the worms mounted on a common altitude drive shaft  240 . A stepper motor  245  is mounted on the chassis and linked by a flexible coupling to the altitude drive shaft  240 . 
         [0053]      FIG. 5  provides an overview illustration of a front and rear view of single optical frame  165 . The azimuth axis  295  of frame  165  and altitude axis  290  of each lens holder  195  are shown. Thus, optical frame  165  can rotate about the azimuth axis and each lens holder  195  can tilt up or down by rotating around their corresponding altitude axis  290 . 
         [0054]      FIG. 5A  depicts an example one of the arrayed opto-mechanical component sets from the optical frame  165 , which includes an azimuth frame  210 , a concentrating element  250  mounted on a lens holder  195 , and an altitude frame  170  and the related mechanical structure and pivot points. 
         [0055]    The concentrating element  250  can be a Fresnel or other imaging lens or a non-imaging device such as a waveguide or Winston cone. The preferred configuration of the concentrating element  250  is to be constructed such that the resultant optical path is directed off-axis from the geometrical center line of the lens holder  195 . This arrangement ensures that the mechanical pivot points  280  and  285  can be coincident with the altitude axis  290  and azimuth axis  295  of the mechanical tracking assembly and that the pivot axes are symmetrical with the physical center lines of the lens holder  195 . The symmetry thus defined ensures the maximum packing density of concentration elements  250  in all tracking positions. 
         [0056]      FIG. 5B  schematically depicts the light path from the concentrating element  250  and through an opto-mechanical joint assembly  500 . As illustrated opto-mechanical joint assembly  500  typically comprises light concentrating element  250  mounted on a rotatable frame assembly configured to rotate about at least two axes. For example, the rotatable frame assembly can include a concentrator holder (see lens holder  195  in  FIG. 5A ) able to rotate around altitude axis  290  and azimuth frame  210  able to rotate about azimuth axis  295 . 
         [0057]    The opto-mechanical joint assembly  500  can comprise of a series of reflective surfaces represented by two orthogonally rotating reflective surfaces  260 ,  265 . Reflective surfaces  260  and  265  can be arranged in a manner that folds or redirects the converging light from concentrating element  250  along an optical path such that the optical path is directed to a fixed location  301  regardless or independent of orientation of the concentrating element  250  about the two tracking axes  290 ,  295 . This arrangement makes possible a stationary interface point represented by fixed location  301  with the balance of the system thus eliminating variable loads on the mechanical drives during tracking or physical wear on the optical components. 
         [0058]    One should appreciate that the fixed location  301  in the example illustrated comprises a light receiving port in the form of an end of optic fiber  300 . The light receiving port could also include other forms of waveguides other than an optic fiber. Fixed location  301  substantially remains stationary relative to the azimuth axis  295  and altitude axis  290  regardless of how frame  210  rotates or how lens holder  195  tilts. In some embodiments, frame  210  can comprise one or more optic fiber holders (e.g., clips, glue, etc.) that hold optic fiber  300  in place relative to the frame  210 . In such cases, optic fiber  300  can rotate with frame  210  about azimuth axis  295  while the light receiving end of optic fiber  300  remains stationary. In other embodiments, optic fiber  300  can be held stationary by being mounted to other non-moving structures (e.g., enclosures, frames, etc.) in a manner that substantially maintains the receiving end of optic fiber  300  at a fixed location. 
         [0059]    When concentrating element  250  is aligned to receive direct natural sunlight, it collects and focuses or concentrates the light as a converging light beam. Prior to reaching the focal or concentration point the converging light is reflected by the first reflective surface  260  and directed along the altitude axis  290  of the lens holder  195 . 
         [0060]    Then, still prior to reaching the focal or concentration point, the converging light is reflected by the second reflective surface  265 , which is mounted on the azimuth frame  210 , and directed along the azimuth axis  295  toward the fixed location  301  of the receiving end of optic fiber  300 . Through the two reflections along orthogonal axes  290  and  295 , the focal or concentration point is stationary relative to orthogonal translation in the focal plane. Thus, the converging light is incident on the light receiving port located at fixed location  301 . One should appreciate the fixed location  301  is considered substantially fixed relative to opto-mechanical joint assembly  500  or more specifically fixed relative to axes  290  and  295 . As can be see, fixed location  301  also remains substantially stationary relative to an intersection of axes  290  and  295 . 
         [0061]    In  FIG. 6 , the stationary optical manifold  150  is shown from the rear. Concentrated sunlight from the output of each opto-mechanical joint is guided to the collimator  155  along optic fibers  300 . In this embodiment, the stationary optical manifold  150  is composed of a set of plastic optical fibers  300  (only some are shown in  FIG. 6 , for clarity). Other embodiments of the stationary optical manifold  150  can include a molded acrylic plate or rigid optical fiber assemblies. Care is taken to route the plastic optical fibers to minimize curvature, and so minimize the increase in optical angularity and loss of efficiency caused by such curvature. 
         [0062]    The plastic optical fibers  300  can be held in place and orientation at the focal or concentration points of the opto-mechanical joints by fiber holders  180  (see  FIG. 4 ) which are mounted on chassis  160 . The fiber holder  180  can be constructed of a metal in order to conduct heat away from the focus or concentration point. Thus, fiber holder  180  can comprises a heat sink. The “face” or end of the plastic optical fiber is typically held just inside or outside of the focal point, such that the amount of concentration is minimized while maintaining full collection. This configuration reduces the surface temperature at the face of the plastic optical fiber and thus mitigates the related thermal degradation effects. The position of the fixed location of the light receiving port of optic fiber  300  is positioned where the area subtended by the light receiving port, A of , is commensurate with the cross sectional area subtended by concentrated light, A cl , at that point just outside the focal point. The ratio of the areas A of /A cl  is preferably within 10%, more preferably within 5%, and yet more preferably within 1% of value of one. 
         [0063]      FIG. 7  depicts collimator  155 , which receives the output from each opto-mechanical joint in the enclosure  85  via the stationary optical manifold  150  and then combines, re-collimates and redirects the aggregate sunlight through the rear glass panel  130  on the enclosure  85  and then into the entrance of the hybrid light guide  65 . 
         [0064]    Light guide performance is predicated on the intensity and degree of collimation of the injected sunlight. The higher the degree of collimation of the sunlight the further the depth of penetration that is possible into a building core or other internal portions of a structure. Sunlight is inherently collimated but the collection, concentration and transport through various mediums and optical components tends to increase the angularity of the exiting light. Sunlight emerging from the exit face of the plastic optical fibers of the stationary optical manifold will therefore benefit from re-collimation for optimal performance of the light guide. 
         [0065]    The collimator  155  is mounted on the rear of the mounting frame  145 . The collimator  155  includes two perforated racks  305 ,  310  for holding the end faces of the plastic optical fibers  300  of the stationary optical manifold  150  such that the optical axis of each fiber is parallel. The collimator mirror  315  is a highly reflective surface held in a specific parabolic shape intended to optimize the collective collimation of the output in the vertical plane from the aggregated plastic optical fibers  300  mounted in the upper rack  305 . 
         [0066]      FIG. 7A  schematically depicts the aggregated optical path. The upper rack  305  is oriented such that the optical axis of attached fibers will be perpendicular and centered to the collimator mirror  315  entrance. The lower rack  310  is oriented to allow the plastic optical fibers  300  from the lower corner section of the mounting frame  145  to have their optical axis oriented directly toward the rear glass panel  130  without requiring severe curvature in the fibers. Although the output from these fibers is not re-collimated, it is generally parallel with the output from the collimator mirror  315 . Thus the sunlight output from all opto-mechanical joints within the concentration panel are combined and concentrated in a single, mostly re-collimated, beam which is directed into the hybrid light guide  65 . 
         [0067]      FIG. 8  shows an example of an embodiment of a complete optical system for collecting and distributing sunlight as disclosed. A typical light guide  65  includes mechanical construction with prismatic or multi-layer optical film as the primary reflective surface, and extraction film distributed to provide balanced light levels along the length of the light guide. The preferred embodiment of this disclosure includes a hybrid light guide. The hybrid light guide  65  includes integrated fluorescent lamps or other electrically powered light sources along the length of the light guide. The fluorescent lamps supplement the sunlight when it is below a set level of luminance during the day and generally during night operations. 
         [0068]    Control of the sunlight and fluorescent mix is achieved by monitoring the environmental light levels with light level sensors mounted on the light guide. The transition from one lighting mode to the other is done such that the occupants of the illuminated area are unaware of the transition. Thus, the hybrid light guide is able to supply a pre-selected level of illuminance at any time of day or in any weather condition. 
         [0069]    The transition funnel  70  is the channel from the concentration panel  60  to the hybrid light guide  65 . It is optically optimized for improved collimation by a hollow funnel that expands from a size approximating the rear window of the concentration panel to a size that mates with the entry of the light guide. The transition funnel  70  is lined with highly reflective material. The funnel shape is sized such that light rays that are emerging from the concentration panel  60  at an angle are redirected to a path close to parallel with the center line of hybrid light guide  65 . 
         [0070]    In applications where the concentration panel  60  is mounted within the building envelop wall and the rear of the panel is directly accessible to the interior of the building, the transition funnel  70  mounts directly to both the concentration panel  60  and the corresponding hybrid light guide  65 . In applications where the concentration panel  60  is mounted external to the building envelope, the light path must pass through a sealed window panel such that the building envelope is not breached. In this case there will generally be additional light ducting lined with highly reflective material to span the distance from the outside concentration panel  60  to the transition funnel  70 . 
         [0071]    The concentration panel  60  as disclosed is autonomous of all wire connections to the building. The concentration panel  60  can therefore be mounted on a building independent of electrical power or data hookup. Power for the control electronics and motion control is self-generated by a photovoltaic panel  95  that is mounted at the lower edge of the front glass panel  100 . Communication with the light level sensors mounted on the hybrid light guides  65 , with the building lighting automation system and for all post-installation calibration or firmware upgrades is accomplished through a wireless communication link. 
         [0072]    In the example shown in  FIG. 8  the concentration panel  60  has a 10 degree slope but the panel could be mounted vertically or have greater or lesser slopes. 
         [0073]    It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the scope of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refers to at least one of something selected from the group consisting of A, B, C . . . and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.