Patent Publication Number: US-2013250580-A1

Title: Induction lamp light fixture

Description:
RELATED APPLICATIONS 
     The present application is based on, and claims priority from, Provisional Application No. 61/175,664, filed May 5, 2009, and is related to U.S. patent application Ser. No. 12/248,693, filed Oct. 9, 2008 and International Application Number PCT/US2008/82939, filed Nov. 10, 2008, the disclosures of which are hereby incorporated by reference herein in their entirety. 
    
    
     BACKGROUND 
     Induction fluorescent lamps offer the potential for increased life, lumen maintenance and efficacy for lighting applications. 
     Many lighting applications employing an induction fluorescent lamp will result in a fairly diffusive distribution characteristic in terms of the flux exiting the fixture. The diffusive nature of the distribution limits, both the controlled distribution of the light pattern from the fixture and the resultant effective area of illuminated horizontal surface such as a road surface. Furthermore, the diffusive nature of the induction lamp also presents challenges in terms of fixture efficiency relative to the amount of light that gets trapped within a fixture geometry. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       One or more embodiments are illustrated by way of example, and not by limitation, in the figures of the accompanying drawings, wherein elements having the same reference numeral designations represent like elements throughout and wherein: 
         FIG. 1  is a side view of a street lamp having a cobra head light fixture according to an embodiment; 
         FIG. 2  is a perspective view of a cobra head light fixture according to an embodiment; 
         FIG. 3  is a reverse perspective view of the cobra head light fixture of  FIG. 2 ; 
         FIG. 4  is a rear perspective view of the cobra head light fixture of  FIG. 2 ; 
         FIG. 5  is a front elevation view of the cobra head light fixture of  FIG. 2 ; 
         FIG. 6  is a rear elevation view of the cobra head light fixture of  FIG. 2 ; 
         FIG. 7  is a right side elevation view of the cobra head light fixture of  FIG. 2 ; 
         FIG. 8  is a left side elevation view of the cobra head light fixture of  FIG. 2 ; 
         FIG. 9  is a top plan view of the cobra head light fixture of  FIG. 2 ; 
         FIG. 10  is a bottom plan view of the cobra head light fixture of  FIG. 2 ; 
         FIG. 11  is a left rear view of the cobra head light fixture of  FIG. 2 ; 
         FIG. 12  is a bottom right view of the cobra head light fixture of  FIG. 2 ; 
         FIG. 13  is a left side section view of the cobra head light fixture of  FIG. 2 ; 
         FIG. 14  is a right side section view of the cobra head light fixture of  FIG. 2 ; 
         FIG. 15  is a right rear perspective view of the cobra head light fixture of  FIG. 2  with an upper cover removed; 
         FIG. 16  is a left rear perspective view of the cobra head light fixture of  FIG. 2  with the upper cover removed; 
         FIG. 17  is a top plan view of the cobra head light fixture of  FIG. 2  with the upper cover removed; 
         FIG. 18  is a bottom plan view of the cobra head light fixture of  FIG. 2  with a lower optic lens removed; 
         FIG. 19  is a left side elevation view of the cobra head light fixture of  FIG. 2  with the upper cover removed; 
         FIG. 20  is a front elevation view of the cobra head light fixture of  FIG. 2  with the upper cover removed; 
         FIG. 21  is a front perspective view of the cobra head light fixture of  FIG. 2  with the upper cover removed; 
         FIG. 22  is a front elevation view of the cobra head light fixture of  FIG. 2  with the upper cover and lower optic lens removed; 
         FIG. 23  is a rear elevation view of the cobra head light fixture of  FIG. 2  with the upper cover and lower optic lens removed; 
         FIG. 24  is a top plan view of the cobra head light fixture of  FIG. 2  with the upper cover removed; 
         FIG. 25  is a bottom plan view of the cobra head light fixture of  FIG. 2  with the lower optic lens removed; 
         FIG. 26  is a right perspective view of the lower optic lens of the cobra head light fixture of  FIG. 2 ; 
         FIG. 27  is a front elevation view of the lower optic lens of the cobra head light fixture of  FIG. 2 ; 
         FIG. 28  is a right side elevation view of the lower optic lens of the cobra head light fixture of  FIG. 2   
         FIG. 29  is a rear elevation view of the lower optic lens of the cobra head light fixture of  FIG. 2 ; 
         FIG. 30  is a top interior plan view of the lower optic lens of the cobra head light fixture of  FIG. 2 ; 
         FIG. 31  is a bottom exterior plan view of the lower optic lens of the cobra head light fixture of  FIG. 2 ; 
         FIG. 32  is a lower rear perspective view of the lower optic lens of the cobra head light fixture of  FIG. 2 ; 
         FIG. 33  is a lower front perspective view of the lower optic lens of the cobra head light fixture of  FIG. 2 ; 
         FIG. 34  is a depiction of candle distribution of the cobra head light fixture according to an embodiment; 
         FIG. 35  is a depiction of another candle distribution of the cobra head light fixture according to an embodiment; 
         FIG. 36  is a depiction of another candle distribution of the cobra head light fixture according to an embodiment; 
         FIG. 37  is a right bottom perspective view of the cobra head light fixture of  FIG. 2  with the lower optic lens removed; 
         FIG. 38  is a rear bottom perspective view of the cobra head light fixture of  FIG. 2  with the lower optic lens removed; 
         FIG. 39  is a collection of views of a shoebox head light fixture according to another embodiment; 
         FIG. 40  is a bottom plan view of the shoebox head light fixture of  FIG. 39 ; 
         FIG. 41  is a side plan view of the shoebox head light fixture of  FIG. 39 ; 
         FIG. 42  is a depiction of candle distribution of the shoebox head light fixture of  FIG. 30 ; and 
         FIG. 43  is a side perspective view of a garage or canopy light fixture according to an embodiment; 
         FIG. 44  is a side plan view of the garage or canopy light fixture of  FIG. 43 ; 
         FIG. 45  is a depiction of candle distribution of the garage or canopy light fixture of  FIG. 43 ; 
         FIG. 46  is a side perspective view of a wall pack light fixture according to an embodiment; 
         FIGS. 47A and 47B  are side and top plan views, respectively, of the wall pack light fixture of  FIG. 46 ; 
         FIG. 48  is a depiction of candle distribution of the wall pack light fixture of  FIG. 46 ; 
         FIG. 49  is a side perspective view of a walkway light fixture according to an embodiment; 
         FIGS. 50A and 50B  are side views of the light fixture of  FIG. 46  and a base according to an embodiment for use with the light fixture of  FIG. 46 ; 
         FIG. 51  is a depiction of candle distribution of the walkway light fixture of  FIG. 49  having type V prismatic refractor optics; 
         FIG. 52  is a depiction of foot candle plot of the walkway light fixture of  FIG. 49  having type V prismatic refractor optics; 
         FIG. 53  is a depiction of candela plot of the walkway light fixture of  FIG. 49  having type V prismatic refractor optics; 
         FIG. 54  is a depiction of candle distribution of the walkway light fixture of  FIG. 49  having type III prismatic refractor optics; 
         FIG. 55  is a depiction of foot candle plot of the walkway light fixture of  FIG. 49  having type III prismatic refractor optics; 
         FIG. 56  is a depiction of candela plot of the walkway light fixture of  FIG. 49  having type III prismatic refractor optics; 
         FIG. 57  is a high-level functional block diagram of a controller according to an embodiment; 
         FIG. 58  is a side view of a street lamp having a cobra head light fixture according to another embodiment; 
         FIG. 59  depicts a high-level functional process flow of at least a portion of lighting control system according to an embodiment; 
         FIG. 60  is a top plan view of a light fixture according to another embodiment; 
         FIG. 61  is a side view of the light fixture of  FIG. 60 ; 
         FIG. 62  is a side section view of the light fixture of  FIG. 60 ; 
         FIG. 63  is an isometric view of the light fixture of  FIG. 60 ; 
         FIG. 64  is an other isometric view of the light fixture of  FIG. 60 ; 
         FIG. 65  is a bottom view of the light fixture of  FIG. 60 ; 
         FIG. 66  is a perspective view of a cobra head light fixture reflector according to an embodiment similar to  FIG. 24 ; and 
         FIG. 67  is a perspective view of a cobra head light fixture reflector according to another embodiment similar to  FIG. 66 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  depicts a perspective view of a lighting device  100  having a cobra head light fixture according to an embodiment of the present invention. Lighting device  100  is installed on a surface  102  by way of a pedestal  104 . In at least some embodiments, surface  102  comprises ground, roadway, or other supporting surface. In at least some embodiments, pedestal  104  comprises any of a number of supportive materials such as stone, concrete, metal, etc. 
     Lighting device  100  comprises a vertically extending support pole  106 . In at least some embodiments, support pole  106  may extend horizontally or at a different angle in-between horizontal and vertical. In at least some embodiments, support pole  106  is hollow; however, in other embodiments different configurations may be possible. In at least some embodiments, support pole  106  may be comprised of metal, plastic, concrete and/or a composite material. 
     In at least some embodiments, support pole  106  also provides a conduit through which electricity is supplied to the light fixture. For example, a connection to a mains or other power source may be provided. 
     Lighting device  100  comprises a light fixture  108 , i.e., a cobra head light fixture physically connected to support pole  106 . Cobra head light fixture  108  comprises an induction-based light source for providing illumination to an area adjacent support pole  106 . 
     Light fixture  108  is an induction-based light source in order to provide increased lifespan and/or reduce a required initial energy requirement for illumination. An induction-based light source does not use electrical connections through a lamp in order to transfer power to the lamp. Electrode-less lamps transfer power by means of electromagnetic fields in order to generate light. In an induction-based light source, an electric frequency generated from an electronic ballast is used to transfer electric power to an antenna coil within the lamp. In accordance with at least some embodiments, light fixture  108  may have an increased lifespan with respect to other types, e.g., incandescent and/or florescent light sources having electrodes. In accordance with at least some embodiments, light fixture  108  may have a reduced initial energy requirement for start up of the light source. In at least some embodiments, lighting device  100  receives power from a 24 volt power source for provision to lighting fixture  108 . In at least some other embodiments, lighting device  100  receives power from a mains power supply and converts the received power to a 24 volt power level for use by lighting fixture  108 . 
     In at least some embodiments, light fixture  108  is electrically connected, either directly or indirectly, to a power source. In at least some alternate embodiments, lighting device  100  may comprise more than one light fixture. In at least some embodiments, light fixture  108  may be arranged to provide illumination in a directional manner, i.e., downward, upward, etc., with respect to an orientation of the light source. In at least some embodiments, lighting device  100  may comprise a plurality of light fixtures arranged at differing elevations and/or at different angular spacing about support pole  106 . 
     In at least some embodiments, induction-based light fixture  108  comprises a light sensor arranged to trigger activation of the induction-based light source based on a detected light level. In at least some embodiments, the detected light level is determined with respect to a particular area proximate support pole  106 . 
     In at least some embodiments, induction-based light fixture  108  comprises a controller integral with the light fixture for controlling activation and/or operation of the light fixture. In at least some other embodiments, lighting device  100  comprises the controller integral thereto, e.g., attached to or within support pole  106 , for controlling activation and/or operation of the light fixture. In at least some still further embodiments (for example, as depicted in  FIG. 58 ), lighting device  100  is coupled to an external controller  5800  configured to control activation and/or operation of light fixture  108  and/or lighting device  100 . 
     Cobra head light fixtures which have enhanced lateral, and generally outward distribution characteristics significantly enhance their utility and efficiency in roadway application by maximizing the area of effectively illuminated roadway surface. Specifically, enhanced fixture geometries that reduce the flux at nadir while enhancing the flux between 45° and 90° results in a much more effective and efficient distribution characteristic for roadway and exterior lighting applications. This enhancement results in significantly lower levels of modulation as defined as the ratio of maximum and minimum light levels between fixture heads and contributes to the evenness of illuminance distribution characteristics on horizontal surfaces and roadways. 
     Reducing modulation, in at least some embodiments, reduces the number of fixtures required in a specified area required to maintain a specified illuminance level, thereby reducing capital and energy costs. 
     Secondly in at least some embodiments, induction-based fixtures have relatively low fixture efficiencies due to the relatively large size of the tubular geometry of the typical induction lamp relative to the size of the primary reflector surfaces within the fixture. This ratio limits the amount of flux that exits the fixture due to internal entrapment. Internal fixture losses are primarily due to the occlusion of inter-reflections within the lamp fixture geometry. In this case, fixture efficiency is defined as the ratio of the total amount of flux, exiting a fixture relative to the total amount of light produced by the lamp. In the energy efficiency arena, maximizing fixture efficiency is vitally important for energy savings, particularly in roadway applications. 
     Developing wider distribution characteristics, and increasing the fixture efficiency for cobra head type applications is particularly important in at least some embodiments in order to achieve increases in power efficiency in the way we illuminate the roadway and related exterior lighting applications including parking, walkway and pathway applications. 
     One or more embodiments of the present invention describe a novel induction based cobra head fixture geometry that employs multiple internal optics and lamp positioning for enhanced distribution and fixture efficiency characteristics. 
     The enhanced optics include one or more of the following specific embodiments: 
     1) Concave optics—A radially symmetric, concave and reentrant convex reflector is positioned over the circular geometry of the induction lamp that enhances the internal cavity reflection out of the fixture body. The concavity is symmetrically positioned around a reentrant convex cone that is aligned with the center axis of the induction lamp. This radially symmetric, concave surface acts as a primary reflector and enhances the internal reflection process. Flux being directed upwards and to the center of the fixture concavity is directed outwards, thereby enhancing the optical efficiency of the overall fixture. This internal concavity reduces the amount of entrapment losses that occur with traditional flat or simple curved optics. 
     This radially symmetric reflector positioned over the circular geometry of the induction lamp enhances the overall fixture efficiency by maximizing the effectiveness of the internal reflection. A larger proportion of the upward emerging flux experiences a single or secondary reflection out of the fixture cavity. This novel, radially symmetric internal reflector enhances the overall fixture efficiency for induction type lamp geometries. 
     2) Lamp positioning—the cobra head employs an enhanced lamp positioning within the geometry of the fixture cavity increasing the forward flux distribution which contributes to a wider distribution. This is particularly important in roadway applications in at least some embodiments where one is interested in maximum light distribution forward from the actual pole mounted fixture head. The front surface of the upper reflector positioned forward of the induction lamp has been designed to provide an enhancement on the forward distribution from the cobra head geometry. Flux exiting the lamp geometry, at 90° to approximately 120° will experience a single reflection on this forward mounted reflector. 
     The lamp is uniquely positioned within the reflective and transmissive optics, such that no direct component exits the fixture above 90°, thereby enhancing the dark sky friendliness of this geometry. In at least some embodiments, a minimum amount of direct component exits the fixture above 90°. 
     3) Transparent optic—the lower half of the cobra head fixture is encapsulated within a single transparent optical unit. This encapsulation allows for both direct transmission of flux from the lamp and direct transmission from inter-reflections from the upper reflector. 
     The surrounding sides of the transparent encapsulation are sized and angled to produce as much surface normal to exiting flux as possible. The normal position of the transparent surfaces reduces the amount of surface losses that occur. This normal positioning of the encapsulating surround also enhances the lateral distribution characteristics out of the fixture. The large almost vertical sides of the transparent material allow for an enhanced lateral distribution contributing to a much wider distribution of flux on horizontal surfaces, thereby reducing modulation and enhancing evenness of illuminance on roadway surfaces. 
     4) Refractor optics—a radially symmetric refractor geometry is molded into the lower encapsulation as an integral element. This refractor geometry is designed explicitly to maximize the lateral distribution of flux, exiting the fixture. Flux, emitted directly downwards within 30 to 40° from nadir from the induction lamp is refracted as it passes through the encapsulated lens geometry. The integrally molded refractor geometry reduces the flux at nadir and enhances the outward redirection of flux contributes to a much wider distribution from the cobra head fixture. 
       FIG. 2  depicts a front perspective view of a cobra head light fixture  200  according to an embodiment, e.g., light fixture  108  ( FIG. 1 ) may be a cobra head light fixture as depicted in  FIG. 2 . Light fixture  200  comprises a top cover  202 , a lower cover  204 , and a lens  206  connected together. In at least some embodiments, top cover  202  is connected directly to at least lower cover  204 . Lens  206  covers an induction-based light source, e.g., an induction-based light bulb, and directs the illumination provided by the light source from the light fixture  200 . 
     In at least some embodiments, light fixture  200  comprises a specular reflector optimized for induction lamp geometry. In at least some embodiments, lens  206  is an acrylic lens with Type III, medium throw prescription optics. 
     Due to the use of the induction-based light source, top cover  202  and/or lower cover  204  may be constructed of a polycarbonate material. In at least some embodiments, top cover  202  is removably connected to lower cover  204 . In at least some embodiments, lens  206  is removably connected to lower cover  204 . 
     In at least some embodiments, lens  206  is transparent. In at least some other embodiments, lens  206  is at least partially transparent. 
       FIG. 3  depicts a rear perspective view of cobra head light fixture  200  according to an embodiment. Lower cover  204  comprises a connection point  300  for connecting light fixture  200  to support pole  106  ( FIG. 1 ). Connection point  300  comprises a throughhole  302  to the interior of light fixture  200 . Throughhole  302  surrounds a sleeved portion  304  of a casting  306 , described in more detail below. 
       FIG. 4  depicts a rear right side perspective view of light fixture  200 . 
       FIG. 5  depicts a front elevation view of light fixture  200 . 
       FIG. 6  depicts a rear elevation view of light fixture  200 . Throughhole  302  of lower cover  204  is visible in  FIG. 6 . 
       FIG. 7  depicts a right side elevation view of light fixture  200  and  FIG. 8  depicts a left side elevation view of the light fixture. 
       FIG. 9  depicts a top plan view of light fixture  200  and  FIG. 10  depicts a bottom plan view of the light fixture. 
     As depicted in  FIG. 10 , lens  206  comprises an integrated refractor optic portion  1000 , as described above. Also, an integrated heat sink  1002  is visible in  FIG. 10 . In at least some embodiments, heat sink  1002  is formed as an integrated portion of casting  306  ( FIG. 3 ). In at least some embodiments, casting  306  structurally connects light fixture  200  to support pole  106  ( FIG. 1 ) and lower cover  204 . Additionally, casting  306  comprises heat sink  1002  for light fixture  200 . In at least some embodiments, the integrated nature of heat sink  1002  enable an extended system life. 
       FIG. 11  depicts a left rear perspective view of light fixture  200  and  FIG. 12  depicts a bottom right perspective view of the light fixture in which refractor optic portion  1000  is visible. 
       FIG. 13  depicts a left side cross-section view of light fixture  200 . Visible in  FIG. 13  are a reflector  1300  connected with lens  206  and within lower cover  204  and a portion top cover  202 . In at least some embodiments, reflector  1300  is connected with lower cover  204  and not to lens  206 . Reflector  1302  is arranged to reflect illumination received from an induction-based light source  1302  through lens  206 . 
       FIG. 14  depicts a right side cross-section view of light fixture  200 . 
       FIG. 15  depicts a right rear perspective view of light fixture  200  with top cover  202  removed. The upper exterior of reflector  1300  is visible within light fixture  200 . A central hemispherical (half donut-shaped) convex, when viewed from the top, portion  1500  of reflector  1300  corresponds to a region of the reflector within which an induction-based light source is positioned on the underside. In at least some embodiments, central hemispherical portion  1500  is less than hemispherical comprising a cord slice of a sphere. 
     An upward extending, when viewed from the top, peripheral region  1502  extends from the circular edge of central hemispherical portion  1500 . Peripheral region  1502  forms a radially extending reflector having a plurality of internal reflection panels  1504  radially spaced around the central hemispherical portion  1500 . In at least some embodiments, reflection panels  1504  comprise a curvature at the end distal from the edge of central hemispherical portion  1500 . 
     In at least one embodiment, peripheral region  1502  comprises a horizontally extending portion  1505 . Horizontally extending portion  1505  extends horizontally from peripheral region  1502  along a portion of the perimeter of peripheral region  1502  and comprises one or more reflection panels similar to internal reflection panels  1504 . In at least some embodiments, the reflection panels of horizontally extending portion  1505  extend one or more internal reflection panels  1504  radially outward from central hemispherical portion  1500 . 
     A downward extending, when viewed from the top, surround region  1506  extends from the edge of peripheral region  1502 . Surround region  1506  extends toward lower cover  204  and lens  206 . In at least some embodiments, reflector  1300  further comprises a flange extending around the perimeter of surround region  1506  for mounting the reflector to either or both of lower cover  204  and/or lens  206 . 
     A driver  1510  usable in conjunction with light source  1302  and a transformer  1512  are also visible. Driver  1510  is connected with casting  306  ( FIG. 3 ) and positioned atop heat sink  1002 . Transformer  1512  is also connected with casting  306 . Driver  1510  and transformer  1512  are electrically coupled with each other. 
       FIG. 16  depicts a left rear perspective view of light fixture  200 . 
       FIG. 17  depicts a top plan view of light fixture  200  with top cover  202  removed. The position of driver  1510  and transformer  1512  is visible. Also, the shape of reflector  1300  is visible. Reflector  1300  is generally ellipsoid with a central raised portion and optically reflective panels radiating outward from the central raised portion. 
       FIG. 18  is a bottom plan view of light fixture  200  with lens  206  removed. The position of heat sink  1002  is visible. Heat sink  1002  is positioned corresponding to driver  1510 . 
       FIGS. 19 and 20  are a left side elevation view and front elevation view of light fixture  200  with top cover  202  removed. 
       FIGS. 21-25  are front perspective, front elevation, rear elevation, top plan, and bottom plan views, respectively, of reflector  1300 . 
       FIGS. 26-33  are right perspective, front elevation, right side elevation, rear elevation, top interior plan, bottom exterior plan, lower rear perspective, and lower front perspective views, respectively, of lens  206 . 
       FIGS. 34-36  are data points and graphs corresponding to illumination levels of light fixture  200  for different wattage light sources, respectively, 70 Watt, 100 Watt, and 120 Watt. In at least some other embodiments, light fixture  200  comprises a light source wattage of 40, 55, or 80 watts. 
       FIG. 37  depicts a right bottom perspective view of light fixture  200  with lens  206  removed. 
       FIG. 38  depicts a rear bottom perspective view of light fixture  200  with lens  206  removed. 
       FIG. 39  depicts a collection of views of a shoebox head light fixture according to another embodiment. The shoebox head light fixture, in at least some embodiments, replaces light fixture  200  in connection with support pole  106  ( FIG. 1 ). 
       FIG. 40  depicts a bottom plan view of shoebox head light fixture  3900  of  FIG. 39 . Lens  4000  causes the distribution of illumination from light fixture  3900  and heat sink  4002  causes dissipation of heat from the unit. 
       FIG. 41  depicts a side elevation view of shoebox head light fixture  3900  of  FIG. 39  and  FIG. 42  depicts a light illumination distribution graph of shoebox head light fixture  3900 . 
     In at least some embodiments, light fixture  200  comprises a twist lock photocell for automatic on/off control of the light fixture. 
       FIG. 43  is a side perspective view of a garage or canopy light fixture  4300  according to an embodiment. Garage light fixture  4300  comprises a lens  4302  having, in at least some embodiments, five sides for the distribution of illumination from the light fixture. In at least some embodiments, garage light fixture  4300  is coupled to a ceiling or overhead mounting mechanism. 
     Light fixture  4300  also comprises a sensor  4304  positioned at a bottom of the light fixture. In at least some embodiments, sensor  4304  is a low-voltage, e.g., 24 volt, occupancy sensor. In at least some further embodiments, sensor  4304  comprises a gasketed removable lens for preventing and/or minimizing entry of water or other elements into the sensor interior. In at least some embodiments, sensor  4304  comprises a lens configured for an installation mounting height for peak (or optimized) performance as well as being at least partially masked for directional sensing. In at least some embodiments, sensor  4304  corresponds to sensor  5707  ( FIG. 57 ). 
     As depicted light fixture  4300  also comprises an air gap  4306  between the top of the fixture (which in at least some embodiments houses a power source or ballast system) and a lamp chamber, e.g., a lower portion of the housing and/or lens  4302 . Air gap  4306  prevents heat generated by an induction-based light source within light fixture  4300  from increasing the maximum power source, e.g., ballast, temperature and thus increases the expected life of the power source system, e.g., ballast. 
       FIG. 44  is a side plan view of the garage or canopy light fixture  4300  ( FIG. 43 ) depicting particular dimensions of the fixture in at least one embodiment. 
       FIG. 45  is a depiction of a graph of the candle distribution of the garage light fixture  4300  ( FIG. 43 ). The induction-based light source within light fixture  4300  is positioned vertically within lens  4302  to allow for a uniform Type IV distribution as seen in the polar candela graph of  FIG. 45 . In at least some embodiments, light source positioning with respect to an internal reflector and the lens is a critical determinant in creating a desired fixture light distribution type. 
       FIG. 46  is a side perspective view of a wall pack light fixture  4600  according to an embodiment. Wall pack light fixture  4600  comprises a lens  4602  having, in at least some embodiments, four sides for the distribution of illumination from the light fixture. In at least some embodiments, wall pack light fixture  4600  is coupled to a wall or other side mounting mechanism. In at least some embodiments, an induction-based light source within light fixture  4600  and an internal specular aluminum reflector are mounted at approximately a 45 degree angle within the fixture in order to maximize light output through the lens. Wall pack light fixture  4600  also comprises a sensor  4604  similar to sensor  4304  ( FIG. 43 ). 
       FIGS. 47A and 47B  are side and top plan views, respectively, of the wall pack light fixture  4600  ( FIG. 46 ) depicting particular dimensions of the fixture in at least one embodiment. 
       FIG. 48  is a depiction of a graph of the candle distribution of the wall pack light fixture  4600  ( FIG. 46 ). Similar considerations apply as described above with respect to light fixture  4300 . 
       FIG. 49  is a side perspective view of a walkway light fixture  4900  according to an embodiment. Walkway light fixture  4900  comprises a lens  4902  having a circular horizontal cross section. In at least some embodiments, lens  4902  is comprised of two separate sections mated together. In at least some other embodiments, lens  4902  is formed of a single piece of translucent and/or transparent material. 
       FIGS. 50A and 50B  are side views of the light fixture  4900  ( FIG. 49 ) and a base  5000  according to an embodiment for use with light fixture  4900 . In use, fixture  4900  is coupled atop base  5000 . 
       FIG. 51  is a depiction of a graph of the candle distribution of the walkway light fixture  4900  ( FIG. 49 ) having Type V prismatic refractor optics. Type III distribution comprises a light fixture wherein the street side segment of the half-maximum-intensity iso intensity trace within the longitudinal range in which the point of maximum intensity falls lies partly or entirely beyond the 1.75×mounting height street side longitudinal roadway lines, but does not cross the 2.75×mounting height street side longitudinal roadway lines. 
     Type V distribution comprises a light fixture wherein the light distribution has a circular symmetry, being essentially the same at all lateral angles around the luminaire or light fixture. 
     Each light fixture comprises a specific refractor design to achieve a Type III or Type V distribution. 
       FIG. 52  is a depiction of a foot candle plot of the walkway light fixture  4900  ( FIG. 49 ) having type V prismatic refractor optics. 
       FIG. 53  is a depiction of a candela plot of the walkway light fixture  4900  ( FIG. 49 ) having type V prismatic refractor optics. 
       FIG. 54  is a depiction of a graph of the candle distribution of the walkway light fixture  4900  ( FIG. 49 ) having type III prismatic refractor optics. 
       FIG. 55  is a depiction of foot candle plot of the walkway light fixture  4900  ( FIG. 49 ) having type III prismatic refractor optics. 
       FIG. 56  is a depiction of candela plot of the walkway light fixture  4900  ( FIG. 49 ) having type III prismatic refractor optics. 
       FIG. 57  depicts a high-level functional block diagram of a controller  5700  usable in conjunction with an embodiment, e.g., as controller  5800  or as a controller integrated as part of a light fixture such as the cobra head, garage, wall pack, or walkway light fixtures. Controller  5700  comprises a processor or controller-based device  5702 , an input/output (I/O) device  5704 , a memory  5706 , and a sensor  5707  each communicatively coupled with a bus  5708 . Memory  5706  (which may also be referred to as a computer-readable medium) is coupled to bus  5708  for storing data and information and instructions to be executed by processor  5702 . Memory  5706  also may be used for storing temporary variables or other intermediate information during execution of instructions to be executed by processor  5702 . Memory  5706  may also comprise a read only memory (ROM) or other static storage device coupled to bus  5708  for storing static information and instructions for processor  5702 . Memory  5706  may comprise static and/or dynamic devices for storage, e.g., optical, magnetic, and/or electronic media and/or a combination thereof. 
     I/O device  5704  may comprise a display, such as a cathode ray tube (CRT) or a flat panel display or other illuminating devices such as illuminated icons or pre-arranged light emitting diodes, for displaying information, alphanumeric and/or function keys for communicating information and command selections to the processor  5702 , a cursor control device, such as a mouse, a trackball, or cursor direction keys for communicating direction information and command selections to the processor and for controlling cursor movement on the display, or a combination thereof. This input device typically has two degrees of freedom in two axes, a first axis (e.g., x) and a second axis (e.g., y) allowing the device to specify positions in a plane. In at least some embodiments, I/O device  5704  is optional. 
     Sensor  5707  generates a motion and/or occupancy detection signal responsive to detection of motion and/or occupancy by living beings within a predetermined area adjacent lighting device  100 . In at least some embodiments, sensor  5707  is a motion sensor positioned to detect movement within the predetermined area. In at least some embodiments, sensor  5707  is an occupancy sensor positioned to detect occupancy by living beings within the predetermined area. In at least some embodiments, sensor  5707  generates radio frequency emissions, e.g., infrared and/or microwave or other emissions, toward the predetermined area and generates the detection signal in response to changes detected in return signals from the predetermined area. Sensor  5707  generates the detection signal for use by lighting control system  5710  during execution by processor  5702 . 
     Memory  5706  comprises a lighting control system  5710  according to one or more embodiments for determining illumination of induction-based light fixture  108  ( FIG. 1 ). Lighting control system  5710  comprises one or more sets of instructions which, when executed by processor  5702 , causes the processor to perform particular functionality. In at least some embodiments, lighting control system  5710  determines how long light fixture  108  should be illuminated based on at least signals, e.g., information and/or data, received from sensor  5707  such as an occupancy and/or motion sensor, coupled to the controller. 
     In at least some further embodiments, lighting control system  5710  determines when and/or how long light fixture  108  should be illuminated based on a monitored power level of an energy storage device, monitored power generating patterns, e.g., with respect to one or both of solar panels and/or wind turbines, and/or a date-based information, or a combination thereof. 
     In at least one embodiment, lighting control system  5710  determines if light fixture  108  should be illuminated responsive to receipt of a motion/occupancy detection signal from sensor  5707 . Lighting control system  5710  determines if light fixture  108  should be illuminated based on comparing the detection signal value (if applicable) with a sensor threshold value  5712  stored in memory  5706 . If the detection signal value meets or exceeds the sensor threshold value  5712 , control system  5710  causes activation of light fixture  108 . 
     In at least some embodiments, sensor threshold value  5712  may specify one or more different threshold values. In accordance with such an embodiment, if the detection signal exceeds a lowest threshold value and not a next higher threshold value, light fixture  108  may be activated at a reduced or dimmed illumination level. If the detection signal exceeds each of the threshold values, light fixture  108  may be activated at a full illumination level. 
     In at least some embodiments, lighting control system  5710  executes a timer function in conjunction with monitoring for the detection signal in order to dim the illumination level of lighting device  100  during periods of inactivity in the predetermined area adjacent the lighting device. For example, if the timer has exceeded a predetermined inactivity threshold value  5720  (stored in memory  5706 ), lighting control system  5710  causes light fixture  108  to reduce the illumination level to a dimmed level, e.g., a predetermined percentage of the full output level of the device. In at least some embodiments, lighting control system  5710  resets or restarts timer responsive to receipt of a detection signal from sensor  5707 . 
     In at least one embodiment, lighting control system  5710  determines how long light fixture  108  should be illuminated based on comparing an energy potential stored in an energy storage device with an energy storage power level threshold  5714  stored in memory  5706 . In at least some embodiments, energy storage power level threshold  5714  comprises a set of values corresponding to different durations in which light fixture  108  may be illuminated. For example, at a first threshold level, controller  5700  may cause light fixture  108  to illuminate for 4 hours, at a second lower threshold level, the controller may cause the light source to illuminate for 2 hours, etc. In at least some embodiments, energy storage power level threshold  5714  comprises a single value above which the energy storage power level must exceed in order for controller  5700  to cause the light source to illuminate. The energy storage power level threshold  5714  may be predetermined and/or user input to controller  5700 . 
     In at least one embodiment, lighting control system  5710  determines how long light fixture  108  should be illuminated based on comparing a power generating history  5716  stored in memory  5706 . Power generating history  5716  may comprise a single value or a set of values corresponding to a time and/or date based history of the power generated by one or both or each of solar panels and wind turbines. For example, lighting control system  5710  may apply a multi-day moving average to the power generating history of one or both or each of solar panels and wind turbines in order to determine the power generating potential for subsequent periods and estimate based thereon the amount of power which may be expended to illuminate light fixture  108  during the current period. In at least one embodiment, lighting control system  5710  applies a three (3) day moving average to the power generating history of one or both of solar panels and wind turbines. 
     In at least one embodiment, lighting control system  5710  determines how long light fixture  108  should be illuminated based on a date-based power generating estimation  5718  stored in memory  5706 . For example, depending on a geographic installation location of lighting device  100  ( FIG. 1 ), controller  5700  may determine the illumination of light fixture  108  based on a projected amount of daylight for the particular location, e.g., longer periods of darkness during winter in Polar locations as opposed to Equatorial locations. In at least some further embodiments, controller  5700  may be arranged to cause illumination of light fixture  108  for a predetermined period of time based on information from one or more of energy storage power level threshold  5714 , power generating history  5716 , and/or date-based power generating estimation  5718  and after termination of the predetermined period be arranged to cause illumination of the light source responsive to a signal from a motion sensor for a second predetermined period of time. 
     In at least some further embodiments, lighting control system  5710  determines when light fixture  108  should be illuminated based on receipt of a signal from an occupancy or traffic detector, e.g., a motion sensor operatively coupled with controller  5700 . 
     In at least some embodiments, controller  5700  also comprises an electrical connection to a mains power supply. The mains power supply connection may be used in a backup/emergency situation if neither of the solar panels, wind turbine, or energy storage device are able to supply sufficient power levels to power light fixture  108 . In another embodiment, the mains power supply connection may be used to return power generated by lighting device  100  to a power supply grid. In at least some embodiments, the returned electric power may be returned for free or for a predetermined price. 
     In at least some embodiments, controller  5700  regulates the supply of electricity to light fixture  108 . By regulating the supplied electricity, controller  5700  may prevent and/or minimize unexpected spikes or drops in the supplied electricity level to light fixture  108 . In at least some embodiments, controller  5700  may also direct from which component light fixture  108  receives electricity, e.g., energy storage device or directly from wind turbine, solar panels, etc. 
     In at least some embodiments, controller  5700  also comprises a light sensor to determine if a predetermined threshold has been met in order to transfer electricity to light fixture  108  to cause the light source to activate and generate illumination. In at least some alternate embodiments, light fixture  108  comprises the light sensor. The light sensor is a switch controlled by a detected light level, e.g., if the light level is below a predetermined threshold level, the switch is closed and electricity flows to light fixture  108 . 
       FIG. 58  depicts a side view of a street lamp having a cobra head light fixture according to another embodiment including a controller  5800  connected to the street lamp for controlling the lamp. 
       FIG. 59  depicts a high-level functional process flow  5900  of at least a portion of lighting control system  5710  according to an embodiment. 
     The process flow begins at either activate light device functionality  5902  or deactivate light device functionality  5904 . In at least some embodiments, upon powering up of lighting device  100 , the device automatically begins operation in an active or illuminated state corresponding to activate light device functionality  5902 . In at least some other embodiments, device  100  automatically begins operation in a dark or non-illuminated state corresponding to deactivate light device functionality  5904 . 
     Given a starting state of activate light device functionality  5902 , after expiration of a first timer set by control system  5710  ( FIG. 57 ), which in at least some embodiments inherently means that no detection signal has been received from sensor  5707 , the flow of control proceeds to dim light device functionality  5906 . During execution of dim light device functionality  5906 , control system  5710  causes light source  108  to dim or reduce the illumination level provided to the area adjacent lighting device  100  by a predetermined amount. 
     In response to receipt of a detection signal from sensor  5707  (indicative of either motion and/or occupancy in the predetermined area adjacent lighting device  100 ), the flow of control returns to activate light device functionality  5902 . 
     If a detection signal from sensor  5707  is not received during dim light device functionality  5906  execution and a second timer expires, the flow of control proceeds to deactivate light device functionality  5904 . During execution of device light functionality  5904 , lighting control system  5710  execution causes light fixture  108  to cease illuminating, i.e., turn off the light source. Similar to dim light device functionality  5906 , in response to receipt of a detection signal from sensor  5707 , the flow of control returns to activate light device functionality  5902 . 
     In at least some embodiments, the above-described fixtures are installed in exterior applications, i.e., exterior to a building or other enclosed structure. For example, the lighting device  100  may be installed along a walkway or path along which individuals move. In at least some embodiments, lighting device  100  is installed in exterior applications to the exclusion of interior applications. That is, in at least some embodiments, lighting device  100  is not installed within a building or other enclosed structure. 
       FIG. 60  is a top plan view of an induction-based light fixture  6000  according to another embodiment. Light fixture  6000  comprises a hinge  6002  coupled to a perimeter of the fixture for enabling access to a power source, e.g., a ballast, mounted in the base of the light fixture. Light fixture  6000  also comprises a latch  6004  or other closure or retention mechanism at an opposing side of the perimeter of the light fixture from hinge  6002  for retaining the light fixture lens in a closed position. Light fixture  6000  also comprises a lens  6006  positioned and configured to direct luminance generated by the induction-based light source toward a predetermined area adjacent lighting device  100  ( FIG. 1 ). In at least some other embodiments, light fixture  6000  comprises different opening and/or closing mechanisms for providing access to the enclosed light source. In at least some other embodiments, the opening and/or closing mechanism is usable to gain access to the induction-based light source within light fixture  6000 . 
     Light fixture  6000  is depicted such that a base  6008  of the light fixture is visible in  FIG. 60 . In at least some embodiments, base  6008  is usable to mount light fixture  6000  to a ceiling or other support mechanism for the light fixture. 
       FIG. 61  is a side view of the light fixture of  FIG. 60  including lens  6006 . Lens  6006  is generally a segmented or flat-topped conical shape in form. As depicted light fixture  6000  further comprises a base mounting plate  6010  for enclosing base  6008  and providing, in cooperation with hinge  6002  and latch  6004  access to the interior of the base. Light fixture  6000  further comprises a lens mounting plate  6012  to which lens  6006  is coupled and, in turn, which is coupled to base mounting plate  6010  via spaced connecting segments  6014 . In at least some embodiments, lens mounting plate  6012  and lens  6006  are coupled via one or more arcuate mounting segments circumferentially spaced about the perimeter of the lens and the lens mounting plate. In at least some embodiments, there are three mounting segments which each comprise an interior channel for retaining a perimeter edge of lens  6006  in contact with an edge of lens mounting plate  6012 . 
     In at least some embodiments, mounting segments  6014  are of a length sufficient to enable dispersion of heat generated by either a power source in base  6008  or the induction-based light source within lens  6006 . In at least some embodiments, greater or fewer number of mounting segments  6014  are used. 
       FIG. 62  is a side section view of the light fixture of  FIG. 60  depicting a power source  6200  positioned within base  6008  and an induction-based light source  6200  positioned within lens  6006 . Additionally, a retention coil  6202  is depicted within lens  6006  and surrounding light source  6200 . For simplicity, electrical connections between retention coil  6202  and power source  6200  and between power source  6200  and mains or other power supply is not shown. 
       FIG. 63  is an isometric view of light fixture  6000  of  FIG. 60 .  FIG. 64  is an other isometric view of light fixture  6000  of  FIG. 60 .  FIG. 65  is a bottom view of light fixture  6000  of  FIG. 60 . 
       FIG. 66  is a perspective view of a cobra head light fixture reflector  6600  according to an embodiment similar to  FIG. 24 . As depicted reflector  6600  is configured for a 40 Watt induction-based light source having a circular cross-section tubular arrangement. The distance A between an inner edge of reflector  6600  and the center of the induction-based light source is 8.34 inches to achieve a desired illumination distribution. In at least some embodiments, the combination of the reflector  6600  design depicted and a 40 Watt induction-based light source arranged as depicted results in an optimal illumination distribution. In at least some other embodiments, greater or smaller dimensions are used. 
       FIG. 67  is a perspective view of a cobra head light fixture reflector  6700  according to an embodiment similar to  FIG. 66 . As depicted reflector  6700  is configured for a 70 Watt induction-based light source having a circular cross-section tubular arrangement. The distance B between an inner edge of reflector  6700  and the center of the near portion of the tube of induction-based light source is 6.18 inches to achieve a desired illumination distribution. In at least some embodiments, the combination of the reflector  6700  design depicted and a 70 Watt induction-based light source arranged as depicted results in an optimal illumination distribution. In at least some other embodiments, greater or smaller dimensions are used. 
     In at least some embodiments, expiration of a timer is interchangeable with accumulation to a preset time, i.e., counting up to a preset time versus counting down from the preset time. 
     Induction lamps as noted, are very efficient at converting energy to light. The additional benefits of embodiments of the lamps, reflectors and refractive elements described in this disclosure make these lamps even more efficient. This allows even lower power consumption for production of the same light output. Moreover, the addition of features allowing the lamp to detect the presence or absence of people and objects allows for the lamp to be extinguished or dimmed when full illumination is not required. This lowers further the average power consumed by the lamp over an extended period, for example, a day or a week. 
     This lower power consumption enables a number of adaptations to be made to the lighting system that would not otherwise be possible. For example, energy collection devices, such as, but not limited to solar panels and wind turbines may be used to supply all (or in at least some embodiments most) of the power required for the lighting device. In at least some embodiments, this is only possible if the time average power collected by an energy collection device exceeds the time average power consumed by the lighting device. In at least some embodiments, the power collected by solar panels and wind turbines is proportional to the size of the collection device, which is limited to being of similar size or area to the lamp housing. 
     Energy collection devices, such as, solar panels and wind turbines cannot in general collect power all of the time. Thus, energy storage devices are required to store energy collected, for later use when the lamp is on or active. Energy storage devices may include but are not limited to batteries such as lead acid, NiC, NiMH and lithium ion. The collection devices and batteries generally produce and store power at low voltages, for example, 24V or less. Therefore, operation of the lamp at low voltages becomes useful to avoid unnecessary and wasteful up-conversion of voltages for driving the lamp from a collector or battery. 
     Furthermore, lamps for public places are typically supplied with high voltage lines, for example 110-240 V because high voltage lines can transmit power over longer distances with lower losses. If the average power consumption of the lamp is significantly reduced, as is the case with the disclosed lamps, efficiently powering the lamp with lower voltages becomes possible because the current losses in the power lines are lower. This allows the lamp controller and electronics to be considerably less expensive because no high to low voltage converters are required, and the housing and electronics no longer need to meet increased safety requirements for the higher voltages. 
     Thus, combinations of power reduction for the illuminated lamp, reduction in average power consumption of the lamp, lower lamp drive voltages and changes in overall systems configurations produce benefits far over and beyond what might be anticipated by any one adaptation alone. 
     It will be readily seen by one of ordinary skill in the art that the disclosed embodiments fulfill one or more of the advantages set forth above. After reading the foregoing specification, one of ordinary skill will be able to affect various changes, substitutions of equivalents and various other embodiments as broadly disclosed herein. It is therefore intended that the protection granted hereon be limited only by the definition contained in the appended claims and equivalents thereof.