Patent Publication Number: US-2023151944-A1

Title: Led luminaire with a cavity and finned interior

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a divisional of U.S. patent application Ser. No. 14/618,884, filed Feb. 10, 2015, entitled “LED Luminaire with a Smooth Outer Dome and a Cavity with a Ridged Inner Surface”, which claims the benefit of U.S. Provisional Patent Application No. 62/005,955, filed May 30, 2014, entitled “Parking Structure LED Light” (Cree Docket No. P2238US0) and U.S. Provisional Patent Application No. 62/009,039, filed Jun. 6, 2014, entitled “Parking Structure LED Light” (Cree Docket No. P2238US0-2). This patent application comprises a continuation-in-part of U.S. patent application Ser. No. 14/462,426, entitled “Outdoor and/or Enclosed Structure LED Luminaire for General Illumination applications, Such as Parking Lots and Structures” (Cree Docket No. P2238US1), filed Aug. 18, 2014, and further comprises a continuation-in-part of U.S. patent application Ser. No. 14/462,391, entitled “Optic Components for Luminaire” (Cree Docket No. P2266US1), filed Aug. 18, 2014, and further comprises a continuation-in-part of U.S. patent application Ser. No. 14/462,322, entitled “Flood Optic” (Cree Docket No. P2300US1), filed Aug. 18, 2014, and further comprises a continuation-in-part of U.S. patent application Ser. No. 14/583,415, entitled “Outdoor and/or Enclosed Structure LED Luminaire”, (Cree Docket No. P2238US2), filed Dec. 26, 2014, all owned by the assignee of the present application, and the disclosures of which are incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present subject matter relates to general illumination lighting, and more particularly, to an optic used to collimate light rays generated by light emitting diodes. 
     BACKGROUND OF THE INVENTION 
     Large areas of open space, such as a farm stead, a parking lot or deck of a parking garage, or a roadway, require sufficient lighting to allow for safe travel of vehicles and persons through the space at all times including periods of reduced natural lighting, such as nighttime, rainy, or foggy weather conditions. A luminaire for rural areas, an outdoor parking lot or covered parking deck, a roadway, etc. must illuminate a large area of space in the vicinity of the luminaire while controlling glare so as not to distract drivers. In some applications such as roadway, street, or parking lot lighting, it may be desirable to illuminate certain regions surrounding a light fixture while maintaining relatively low illumination of neighboring regions thereof. For example, along a roadway, it may be preferred to direct light in a lateral direction parallel with the roadway while minimizing illumination in a longitudinal direction toward roadside houses or other buildings. Still further, such a luminaire should be universal in the sense that the luminaire can be mounted in various enclosed and non-enclosed locations, on poles or on a surface (such as a garage ceiling), and preferably present a uniform appearance. 
     Advances in light emitting diode (LED) technology have resulted in wide adoption of luminaires that incorporate such devices. While LEDs can be used alone to produce light without the need for supplementary optical devices, it has been found that optical modifiers, such as lenses, reflectors, optical waveguides, and combinations thereof, can significantly improve illumination distribution for particular applications. Improved consistency in the manufacture of LEDs along with improvements in the utilization of mounting structures to act as heat sinks have resulted in luminaires that are economically competitive and operationally superior to the conventional incandescent and fluorescent lighting that has been the staple of the industry for decades. As the use of LEDs has matured from their use in warning and other signals to general lighting fixtures, it has become necessary to develop optics that allow for the dispersion of the harsh, intensely concentrated beam of light emitted by the LED into a softer, more comfortable illumination that presents a uniform and even appearance. 
     One way of attaining a more uniform appearance is to control the light rays generated by the LEDs so as to redirect the light rays through and/or out of an optic so that the light presents a uniform appearance when it exits the optic. Redirecting light through the optic can be accomplished through the use of refractive surfaces at a refractive index interface. 
     SUMMARY OF THE INVENTION 
     According to one embodiment, an optical member includes an enclosure comprising an optically transmissive material. The enclosure has an outer surface and an inner surface opposite the outer surface. At least one light redirection feature protrudes from the inner surface. At least one indentation defined on the outer surface is configured to refract light. 
     According to another aspect, an optical member includes a base, a curved surface extending from the base and including an outer surface, an inner surface opposite the outer surface, and a plurality of light redirection features disposed on the inner surface. An LED package comprising a plurality of dies enclosed in a single encapsulant. 
     According to a further aspect, a lighting device includes a housing and a light source. The housing comprises a base, a plurality of fins extending between a central wall and an outer wall on a first surface of the base, and a cavity extending between an outer edge of the first surface and the outer wall. The light source is mounted to the second surface of the base. 
     According to another aspect, a lighting device includes a housing and a cover adapted to be disposed on the housing comprising a prong at a first end and a tab at a second end opposite the first end. The housing includes an opening configured to receive the prong of the cover and a ledge configured to receive the tab such that the cover is secured to the housing. 
     Other aspects and advantages of the present invention will become apparent upon consideration of the following detailed description and the attached drawings wherein like numerals designate like structures throughout the specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an isometric view taken from below of a luminaire incorporating an optical member; 
         FIG.  1 A  is an isometric view taken from above of the luminaire of  FIG.  1   ; 
         FIG.  2    is an exploded isometric view taken from below of a luminaire incorporating an optical member; 
         FIG.  2 A  is a bottom elevational view of an LED element or module; 
         FIG.  3    is an isometric view from below of an embodiment of an optic; 
         FIG.  4    is an isometric view from above of the embodiment of  FIG.  3   ; 
         FIG.  5    is a bottom elevational view of the embodiment of  FIG.  3   ; 
         FIG.  6    is a plan view of the embodiment of  FIG.  3   ; 
         FIG.  7    is a side elevational view of the embodiment of  FIG.  3   ; 
         FIG.  8    is a sectional view taken generally along the lines of  8 - 8  of  FIG.  5   ; 
         FIGS.  8 A and  8 B  are sectional views identical to  FIG.  8    illustrating sample dimensions for the optical member; 
         FIG.  9    is a light ray diagram of a further embodiment of an optic; 
         FIGS.  10 A and  10 B  are side elevation and plan views, respectively, of illumination distributions produced by the embodiment of  FIG.  3   ; 
         FIG.  11    is an isometric view from below of a further embodiment of an optic; 
         FIG.  12    is an isometric view from above of the embodiment of  FIG.  11   ; 
         FIG.  13    is a bottom elevational view of the embodiment of  FIG.  11   ; 
         FIG.  14    is a plan view of the embodiment of  FIG.  11   ; 
         FIG.  14 A  is a plan view identical to  FIG.  14    illustrating sample dimensions for the optical member; 
         FIG.  15    is a side elevational view of the embodiment of  FIG.  11   ; 
         FIG.  16    is a sectional view taken generally along the lines of  16 - 16  of  FIG.  13   ; 
         FIG.  17    is a further side elevational view of the embodiment of  FIG.  11    transverse to the side elevational view of  FIG.  15   ; 
         FIG.  18    is a sectional view taken generally along the lines of  18 - 18  of  FIG.  14   ; 
         FIG.  18 A  is a sectional view identical to  FIG.  18    illustrating sample dimensions for the optical member; 
         FIG.  19 A  is a side elevational view and a plan view of an illumination distribution produced by the embodiment of  FIG.  11   ; and 
         FIG.  19 B  is a plan view of illumination distributions produced by the embodiment of  FIG.  11   . 
     
    
    
     DETAILED DESCRIPTION 
     Disclosed herein is luminaire  50  for general lighting, such as illumination of an open or large enclosed space, for example, in a rural setting, a roadway, a parking lot or structure, or the like. Referring to  FIGS.  1 ,  1 A, and  2   , the luminaire  50  includes a light source such as one or more LED element(s) or module(s)  52  disposed in a housing  54  having a transparent optical member  56  and a cover  205  secured thereto. The luminaire  50  is adapted to be mounted on a device or structure, for example, on an outdoor pole or stanchion  58  and retained thereon by a clamping apparatus  59 . The luminaire  50  may further include an optional reflector  60  and/or an optional shroud  61  secured in any suitable fashion about the optical member  56 . The luminaire  50  may also include an ambient light sensor  222  mounted in a receptable  224  that acts as a switch such that, when the level of ambient light drops below a predetermined threshold, an electrical path is established by the sensor  222  thereby causing the luminaire  50  to illuminate. 
     Each LED element or module  52  may be a single white or other color LED chip or other bare component, or each may comprise multiple LEDs either mounted separately or together on a single substrate or package to form a module including, for example, at least one phosphor-coated LED either alone or in combination with at least one color LED, such as a green LED, a yellow LED, a red LED, etc. In those cases where a soft white illumination with improved color rendering is to be produced, each LED element or module  52  or a plurality of such elements or modules  52  may include one or more blue shifted yellow LEDs and one or more red LEDs. The LEDs may be disposed in different configurations and/or layouts as desired. Different color temperatures and appearances could be produced using other LED combinations, as is known in the art. In one embodiment, each element or module comprises any LED, for example, an MT-G LED incorporating TrueWhite® LED technology or as disclosed in U.S. patent application Ser. No. 13/649,067, filed Oct. 10, 2012, entitled “LED Package with Multiple Element Light Source and Encapsulant Having Planar Surfaces” by Lowes et al., (Cree Docket No. P1912US1-7), the disclosure of which is hereby incorporated by reference herein, as developed and manufactured by Cree, Inc., the assignee of the present application. If desirable, a side emitting LED disclosed in U.S. Pat. No. 8,541,795, filed Oct. 10, 2005, entitled “Side-Emitting Optical Coupling Device” by Keller et al., the disclosure of which is incorporated by reference herein, as developed and manufactured by Cree, Inc., the assignee of the present application, may be utilized. In some embodiments, each LED element or module  52  may comprise one or more LEDs disposed within a coupling cavity with an air gap being disposed between the LED element or module  52  and a light input surface. In any of the embodiments disclosed herein each of the LED element(s) or module(s)  52  preferably have a lambertian or near-lambertian light distribution, although each may have a directional emission distribution (e.g., a side emitting distribution), as necessary or desirable. More generally, any lambertian, symmetric, wide angle, preferential-sided, or asymmetric beam pattern LED element(s) or module(s) may be used as the light source. 
     In one embodiment, the LED package or element  52  may comprise a multi-die LED package, as shown in  FIG.  2 A . The multi-die package includes at least 40 dies  62  disposed under a single encapsulant or other primary optic  64  on a circuit board  67 . In other embodiments, the multi-die package may include 80 dies, or 120 dies, or any number of dies as desired. The optical member  56  may be used with a relatively large LED package having a diameter from about 12.5 mm to about 30 mm, preferably from about 17.5 mm to about 25 mm. In one embodiment, the lighting device  50  may include a module or element as disclosed in co-pending U.S. Patent Application 62/088,375, filed Dec. 5, 2014, entitled “Voltage Configurable Solid State Lighting Apparatuses, Systems, and Related Methods” (Cree Docket No. P2338US0), the disclosure of which is hereby incorporated by reference herein, as developed and manufactured by Cree, Inc., the assignee of the present application. In other embodiments, the LED package may include a plurality of individual LED dies wherein each die has an associated encapsulant. The electrical components of the luminaire  50  are described in greater detail in copending U.S. patent application Ser. No. 14/618,819, entitled “LED Luminaire,” filed contemporaneously herewith (Cree Docket no. P2350US1), owned by the assignee of the present application and the disclosure of which is hereby incorporated by reference herein. 
     Referring to  FIGS.  1 ,  1 A, and  2   , the housing  54  includes a plurality of tapered fins  190 , a plurality of cavities  192  adjacent and between the fins  190 , and an outer wall  194  surrounding the fins  190  and the cavities  192  to provide thermal management of the LED element or module  52 . Specifically, the outer wall  194  of the housing  54  is disposed about and at least partially surrounds a first surface  196  of a base  198  (seen in  FIG.  2   ). Each fin  190  extends between a tapered central wall  200  and the outer wall  194 . Each cavity  192  extends into an associated space  201  between an outer edge  202  of the first surface  196  and the outer wall  194  and between adjacent fins  190 . Each space  201  comprises a void or flow through channel that allows convective air flow therethrough for cooling purposes, and further allows fluid flow to drain rainwater. The first surface  196  slopes to the outer edge  202  such that a thickness of the base  198  near the central wall  200  is greater than a thickness of the base  198  near the outer edge  202  thereof to promote water drainage. The LED element or module  52  is mounted on a second surface  204  of the base  198  opposite the first surface  196 . During operation, heat is dissipated as air flow carries heat produced by the LED element or module  52  through the spaces  20  land cavities  192  and along the surfaces of the fins  190 , the outer wall  194 , and the central wall  200 . Other heat dissipation means may also be used. 
     While ten fins  190  are shown as curved and extending from a substantially linear central wall  200  and the outer wall  194  is shown as being substantially circular in shape, this need not be the case. Thus, for example, fewer or more than ten fins might be used, two or more central walls might be included, or the central wall  200  may be partially or entirely omitted. Alternatively or additionally, some or all of the fins  190  may be linear or be of another shape, the central wall  200  may be curved or some other shape, the outer wall  194  may be square or rectangular or some other shape, and/or the sizes and/or shapes of the cavities and/or the spaces  201  may be varied, as desired. One or more of the fins  190 , the outer wall  194 , and/or the base  198  may be continuous or discontinuous. Preferably, the fins  190 , the outer wall  194 , the base  198 , and the other elements of the housing  154  are made of uncoated aluminum or another suitable material and are integrally formed. 
     In the embodiment illustrated in  FIGS.  1  and  2   , the cover  205  attaches to the housing  54  without the need for separate fastening components. As shown in  FIG.  2   , first and second prongs  206   a ,  206   b  extending from a first end  208  of the cover  205  are received by first and second openings  210   a ,  210   b  in the housing  54 . First and second tabs  212   a ,  212   b  extending from a second end  214  of the cover  205  opposite the first end  208  includes first and second protrustions  213   a ,  213   b , respectively, that snap-fit about respective first and second ledges  216   a ,  216   b  of the housing  54 . During assembly and installation, the first and second prongs  206 ,  206   b  of the cover  205  are inserted into the first and second openings  210   a ,  210   b  of the housing  54  and the cover is allowed to hang freely from the prongs  206  and yet be movable about an axis of rotation  218 . Thereafter, wires may be attached to components in a compartment  219  (seen in  FIG.  2   ) as the cover  205  is hanging freely from the housing  54 . Once connections have been made, the cover  205  may be pivoted about the axis of rotation  218  until the first and second tabs  212   a ,  212   b  of the cover  205  snap over the first and second ledges  216   a ,  216   b  of the housing  54 . To remove the cover  205 , first and second surfaces  220   a ,  220   b  opposite first and second tabs  212   a ,  212   b , respectively, may be pushed together such that the first and second tabs  212   a ,  212   b  are moved from interfering relationship with the first and second ledges  216   a ,  216   b  of the housing  54  and the cover  205  may be pivoted about the point of rotation  218 . In other embodiments, additional fastening components such as screws and/or pins may be used to secure the cover  205  to the housing  54 . 
     Referring to  FIG.  2   , the optical member or enclosure  56  is disposed about the LED package(s) or element(s)  52  to produce a desired light distribution having a desired lumen output level. In the embodiment shown in  FIG.  3   , the optical member  56  comprises a curved portion  68  extending from a base  70 . The curved portion  68  is symmetric about a central axis  72 . An outer surface  74  of the curved portion  68  includes at least one indentation  76  configured to refract light away from the central axis  72 . More specifically, the outer surface  74  is defined by a first portion  77  ( FIG.  7   ) having a frustoconical shape and a second portion  79  ( FIG.  7   ) defining a “free form” or “spline curvature.” “Spline curvature” refers to the design of a surface having varied curvature to enable greater control over the angles and/or spread of the light rays as the rays strike the surface. In other embodiments, the outer surface may by defined by a specific equation, a curve determined by iteratively plotting the points using a differential or quasi-differential equation, and/or a free form curve derived by any methodology, such as empirically, or a combination thereof. The indentation  76  of the illustrated embodiment is defined by first, second, and third planar surfaces  78 ,  80 ,  82  ( FIGS.  5  and  8   ) that approximate a curve  84  ( FIG.  8   ). Each planar surface  78 ,  80 ,  82  ( FIGS.  5  and  8   ) has a frustoconical shape concentric about the central axis  72 . In some embodiments, the indentation  76  may comprise a planar surface, a curved surface, a free form surface, or a combination thereof. In the illustrated embodiment, the slope of the outer surface  74  varies smoothly (in that the change in slope is gradual or minor relative to distance), although discrete light extraction and/or redirection features (including discontinuous features) may be formed thereon as desired to produce a desired light distribution. 
     Referring to  FIGS.  4  and  6   , the optical member  56  includes a plurality of light redirection features  84 , each having an annular shape that is also concentric about the central axis  72 , protruding from an inner surface  86  of the curved portion  68  opposite the outer surface  74 , Further, the inner surface  86  is preferably symmetric about the central axis  72 . In other embodiments, each redirection feature and/or the inner surface  86  may have an annular shape that is concentric about an axis other than the central axis  72 , and/or the optical member  56  may include at least one light redirection feature  84  having a rounded or planar shape, or a plurality of discrete light direction features approximating an annular shape. Still further, the light redirection features may have other shapes, including shapes that extend fully or partially about a center or other point or feature, and/or shapes that are symmetric or asymmetric, smooth or discontinuous, one or more shapes defined by a specific equation, a shape determined by iteratively plotting points using a differential or quasi-differential equation, and/or a free form shape derived by any methodology, such as empirically, or a combination thereof, etc. Further, in some embodiments, adjacent light redirection features  84  distal to the central axis  72  may be spaced farther apart than adjacent light features  84  proximal to the central axis  72 . In other embodiments, adjacent light redirection features  84  distal to the indentation  76  may be spaced farther apart than adjacent light features  84  proximal to the indentation  76 . 
     The optical member  56  substantially redirects the primarily Lambertian distribution of light developed by the LED package  52 . Each light redirection feature  84  of the embodiment illustrated in  FIGS.  6  and  7    has a ridge-shape configured to retract light in this regard. The ridge-shape of the light redirection features shown in  FIGS.  6  and  7    each include a ridge  88  defined by an inner feature surface  90  closer to the central axis  72  and an outer feature surface  92 . The light developed by the LED package  52  is incident on the light redirection features  84  and may be retracted toward the outer surface  74  so that the light passes through the optical member  56  to the outer surface  74  where the light exits the optical member  56 , The outer surface  74  may be domed and comprise an in indentation  76  configured to further refract the light (e.g., away from the central axis  72 ) upon exiting the optical member  56 . The ridge  88  may be filleted as seen in cross section having a radius of curvature of less than about 1.0 mm, preferably less than 0.75 mm, and most preferably less than 0.5 mm. As seen in  FIG.  8   , the inner feature surface may have a finite radius of curvature along a first extent  94  between the inner surface  86  and the ridge  88 . The outer feature surface  92  may be planar along a second extent  96  between the inner surface  86  and the ridge  88 . The first and second extents  94 ,  96  may have a curved surface, a planar surface, and/or a combination thereof, and the curvature may vary from one light redirection feature  84  to another. A portion  98  of the inner surface  86  that extends between the outermost light redirection feature  84  and the base  70  may have a finite radius of curvature. 
     During assembly of the luminaire  20 , the circuit board  67  of the LED package  52  is mounted by any suitable means, such as a bracket with fasteners and/or an adhesive material, for example, a UV curable silicone adhesive, on the second surface  204  of the housing  54 , and the optical member  56  is secured to the housing  54  about the LED package  52  by any suitable means, such as a UV curable silicone adhesive or other adhesive. As seen in  FIG.  2   , wires  53  extend along and inside a channel  57  formed in the housing  54  and connect the LED package  52  to a further circuit board  55  located outside of the optical member  56  and disposed inside a housing  54  of the luminaire  50 . The optical member  56  includes a tab  59  outwardly extending from the base  70  that is positioned over the wires  53  disposed in the channel  57 . Referring to  FIG.  4   , a stub  61  extending from the base  70  adjacent the tab  59  applies pressure to the wires  53  in the channel  57  when the luminaire  50  is assembled. The tab  59  and stub  61  protect the wires  53  and channel  57  from elements such as water. Two locating slots  63   a ,  63   b , each having a semi-circular cylindrical shape, are disposed along an outer edge  65  of the base  70  opposite to one another and equidistant from the tab  59 . The locating slots  63   a ,  63   b  receive protrusions  69   a ,  69   b  ( FIG.  2   ) extending from the second surface  204  of the housing  54 . An adhesive material such as a UV curable silicone adhesive disposed on the second surface  2014  of the housing  54  secures the optical member  56  thereto. 
     The material(s) of the optical member  56  preferably comprises optical grade materials that exhibit refractive characteristics such as glass and/or polycarbonate, although other materials such as acrylic, air, molded silicone, and/or cyclic olefin copolymers, and combinations thereof, may be used. Further, the materials may be provided in a layered arrangement to achieve a desired effect and/or appearance. Preferably, although not necessarily, the optical member  56  is solid, although the optical member  56  may have one or more voids or discrete bodies of differing materials therein. The optical member  56  may be fabricated using procedures such as molding, including glass and/or injection/compression molding, or hot embossing, although other manufacturing methods such may be used as desired. In one embodiment, the optical member  56  comprises glass and is manufactured using glass molding techniques. 
     The light developed by the LED package  52  is incident on the light redirection features  84  and is collimated to some degree and redirected outwardly and away from the central axis  72 . As shown by the rays  100  of  FIG.  9   , the light incident on the redirection features  84  is refracted at the inner surface  86  of the curved portion  68  and refracted again at the outer surface  74  of the curved portion  68 . The degree of redirection is determined by a number of factors, including the curvature and shape of the redirection feature(s)  84  and the surfaces  78 ,  80 ,  82  that define the indentation  76 . In the illustrated embodiment shown in  FIGS.  8 A and  8 B , each optical member has the dimensions recited in the following table, it being understood that the dimensions are exemplary only and do not limit the scope of any claims herein, except as may be recited thereby, together with equivalents thereof: 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                   
                 NOMINAL DIMENSIONS 
               
               
                   
                 REFERENCE 
                 (in., unless otherwise specified) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 FIG. 5 
                   
                   
               
               
                   
                 A 
                 0.66 
                 (radius of curvature) 
               
               
                   
                 B 
                 1.33 
                 (radius of curvature) 
               
               
                   
                 c 
                 2.00 
                 (radius of curvature) 
               
               
                   
                 D 
                 4.8 
                 (radius of curvature) 
               
               
                   
                 E 
                 4.98 
                 (radius of curvature) 
               
               
                   
                 FIG. 7 
               
            
           
           
               
               
               
            
               
                   
                 F 
                 0.2 
               
               
                   
                 G 
                 0.1 
               
               
                   
                 H 
                 1.4 
               
            
           
           
               
               
               
               
            
               
                   
                 FIG. 6 
                   
                   
               
               
                   
                 J 
                 0.122 
                 (radius of curvature) 
               
            
           
           
               
               
               
            
               
                   
                 K 
                 4.94 
               
            
           
           
               
               
               
               
            
               
                   
                 L 
                 2.24 
                 (radius of curvature) 
               
               
                   
                 M 
                 2.49 
                 (radius of curvature) 
               
               
                   
                 N 
                 0.20 
                 (radius of curvature) 
               
            
           
           
               
               
               
            
               
                   
                 P 
                 0.669 
               
               
                   
                 Q 
                 2.94 
               
               
                   
                 R 
                 0.35 
               
            
           
           
               
               
               
               
            
               
                   
                 FIG. 8A 
                   
                   
               
               
                   
                 S 
                 173.0 
                 degrees 
               
               
                   
                 T 
                 165.0 
                 degrees 
               
               
                   
                 U 
                 155.0 
                 degrees 
               
               
                   
                 V 
                 0.38 
                 (radius of curvature) 
               
               
                   
                 W 
                 1.00 
                 (radius of curvature) 
               
               
                   
                 X 
                 1.50 
                 (radius of curvature) 
               
               
                   
                 Y 
                 0.04 
                 (radius of curvature) 
               
            
           
           
               
               
               
            
               
                   
                 Z 
                 0.18 
               
            
           
           
               
               
               
               
            
               
                   
                 AA 
                 0.75 
                 (radius of curvature) 
               
               
                   
                 AB 
                 0.63 
                 (radius of curvature) 
               
               
                   
                 AC 
                 1.00 
                 (radius of curvature) 
               
               
                   
                 FIG. 8B 
               
               
                   
                 AD 
                 135.0 +/− 2.5 
                 degrees 
               
               
                   
                 AE 
                 105.0 +/− 2.5 
                 degrees 
               
               
                   
                 AF 
                 80.0 +/− 2.5 
                 degrees 
               
               
                   
                 AG 
                 65.2.0 +/− 2.5 
                 degrees 
               
               
                   
                 AH 
                 50.0 +/− 2.5 
                 degrees 
               
               
                   
                 AJ 
                 0.02 +/− 0.25 
                 (radius of curvature) 
               
               
                   
                   
               
            
           
         
       
     
     The optical member  56  has a thickness defined by the inner and outer surfaces  86 ,  74  that varies. The thickness may range from about 3 mm to about 6 mm, preferably from 3.25 mm to about 5.5 mm, and most preferably from about 3.25 mm to about 5 mm, In some embodiments, the thickness of the curved portion  68  may vary from about 3.7 mm at the indentation  76  to about 4.5 mm at the base  70 . Further, the thickness of the optical member  56  at the light redirection features  84  may range from about 0.26 in. (6.604 mm) to about 0.37 in. (9.398 mm). The curved portion  68  may have a first thickness adjacent to the indentation  76  and a second thickness greater than the first thickness adjacent to the light redirection feature  84 . The optical member  56  illustrated in  FIGS.  3 - 8    may exhibit an optical efficiency of at least about 75%, preferably at least about 80%, and most preferably at least ab out 93%. 
     The overall result, when the LED package  52  is energized, is to produce a desired illumination distribution  102 , for example, as illustrated by the simulation illumination diagrams of  FIGS.  10 A and  10 B .  FIG.  10 A  illustrates the distribution  102  along a first plane on which the central axis  72  lies.  FIG.  10 B  illustrates the distribution  102  produced along a second plane normal to the central axis  72 . The luminaire  50  utilizing the optical member  56  may produce various distributions depending on various parameters such as lumen output and mounting height. For example, as shown in  FIG.  10 B , the luminaire  50  utilizing the optical member  56  and having a lumen output of about 3,200 lumens may generate about 0.2 foot-candles, about 0.5 foot-candles, and about 1.0 foot-candles of light having first, second, and third distributions  102   a ,  102   b ,  102   c , respectively, at mounting heights of about 42 feet, about 18.75 feet, and about 7.5 feet, respectively. Each distribution  102   a ,  102   b ,  102   c  of  FIG.  10 B  includes a first extent  106  in an x-direction along an x-axis  108  and a second extent  110  in a y-direction along a y-axis  112  perpendicular to the x-axis  108 . The first extent  106  and the second extent  110  are symmetric about the x-axis and y-axis  108 ,  112 , respectively. 
       FIGS.  11 - 16    illustrate a further embodiment of an optical member  120  similar to the optical member  56  of  FIGS.  3 - 8    above but having a different shape and illumination distribution. The optical member  120  may be used in the luminaire  20  of  FIGS.  1  and  2   . It should be noted that, while the optical member  120  is transparent such that all features are visible at all times, the profile of each feature is not always shown in the FIGS. for simplicity. 
     Referring to  FIG.  11   , the optical member or enclosure  120  includes a curved portion  124  that extends from a base  126 . As seen in  FIGS.  12  and  14   , the curved portion  124  defines an elongate shape  128  at the base  126  having a major axis  130  and a minor axis  132  transverse to the major axis  130 . The optical member  120  is symmetric about a plane of symmetry  134  that includes the minor axis  132  and which is normal to the base  126 . An outer surface  136  of the curved portion  124  includes at least one indentation  138  that is configured to refract light away from the plane of symmetry  134 . As seen in  FIG.  13   , the indentation  138  is defined at least in part by a line  140  that lies on the plane of symmetry  134 . 
     Referring to  FIGS.  12  and  14   , a plurality of light redirection features  142  protrudes from an inner surface  144  of the curved portion  124  opposite the outer surface  136 . In the illustrated embodiment, each light redirection feature  142  has a curved shape  146  that extends in a linear direction and is parallel to the minor axis  132 , although other orientation(s) and/or spacing(s) may be used to produce a desired illumination distribution. 
     As shown in  FIG.  15   , the outer surface  136  of the curved portion  124  varies between a first side  150  of the optical member  120  and a second side  152  of the optical member  120  opposite the first side  150 . The outer surface  136  defines a “free form” or “spline curvature” as described above. In other embodiments, the outer surface  136  may be defined by a specific equation, a curve determined by iteratively plotting the points using a differential or quasi-differential equation, and/or free formed curvature, or a combination thereof. A first extent  148  adjacent the first side  150  has a curvature approximating or defined by a curve having a first radius of curvature, and a second extent  154  adjacent the second side  152  has a curvature approximating or defined by a curve having a second radius of curvature smaller than the first radius of curvature. In one embodiment where the optical member  120  is used for roadway lighting, the optical member  120  is disposed such that the first side  150  is closer to the stanchion or pole  58  ( FIG.  1   ) and the second side  152  is directed toward the roadway (not shown). 
     As seen in  FIG.  16   , the indentation  138  is formed along the first and second extents  148 ,  154 . The inner and outer surfaces  144 ,  136  of the curved portion  124  define a thickness therebetween, which varies along the minor axis  132 . 
       FIG.  17    illustrates the varied curvature of the outer surface  136  of the curved portion  124  viewed from the first side  150 . Third and fourth extents  153 ,  155  of the outer surface  136  of the curved portion  124  adjacent third and fourth sides  156 ,  157 , respectively, of the optical member  120  are mirror images of one another along the plane of symmetry  134 . The third and fourth extents  153 ,  155  of the outer surface  136  are also “Tree form” or “spline curvatures,” although the curvature may be otherwise defined as desired. 
     As seen in  FIG.  18   , each light redirection feature  142  of the illustrated embodiment has a ridge shape that includes a ridge  158  defined by an inner feature surface  160  closer to the minor axis and an outer feature surface  162 . The ridge  158  may be filleted as seen in cross section having a radius of curvature of between about 0.5 mm and about 2.0 mm, preferably between about 0.75 mm and about 1.5 mm, and most preferably between about 0.85 mm and about 1.2 mm. The inner feature surface  160  may have a finite radius of curvature along a first extent  164  between the inner surface  144  and the ridge  158 . The outer feature surface  162  may be planar along a second extent  166  between the inner surface  144  and the ridge  158 . The first and second extents  164 ,  166  may have curved surfaces, planar surfaces, or a combination thereof. Further, first and second portions  168   a ,  168   b  of the inner surface  144  that extend between the outermost light redirection features  142 N- 1 ,  142 N- 2 , respectively, and the base  126  may have a finite radius of curvature. Further, in some embodiments, adjacent light redirection features  142  distal to the indentation  138  are spaced farther apart than adjacent light features  142  proximal to the central axis  138 . 
     Similar to the optical member  56  described above, the optical member  120  as seen in  FIG.  12    includes a stub  169  extending from the base  126  that applies pressure to the wires  53  in the channel  57  when the luminaire  50  is assembled. Two locating slots  171   a ,  171   b , each having a semi-circular cylindrical shape, are disposed along an outer edge  173  of the base  126  opposite to one another and equidistant from the stub  169 . An adhesive material such as a UV curable silicone adhesive disposed on the inner surface  54   a  of the housing  54  secures the optical member  56  thereto. 
     The light developed by the LED package  52  is incident on the light redirection features  142  and is collimated to some degree and redirected outwardly and away from the plane of symmetry  134 . The degree of redirection is determined by a number of factors, including the curvature and shape of the light redirection feature(s)  142  and the surfaces that define the indentation  138 . In the illustrated embodiment shown in  FIGS.  14 A,  16 A, and  18 A , the optical member  120  has the dimensions recited in the following table, it being understood that the dimensions are exemplary only and do not limit the scope of any claims herein, except as may be recited thereby, together with equivalents thereof: 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                   
                 NOMINAL DIMENSIONS 
               
               
                   
                 REFERENCE 
                 (in., unless otherwise specified) 
               
               
                   
                   
               
             
            
               
                   
                 FIG. 13 
                   
               
               
                   
                 AK 
                 2.57 
               
               
                   
                 AL 
                 2.28 
               
               
                   
                 AM 
                 4.97 
               
               
                   
                 AN 
                 3.67 
               
               
                   
                 AP 
                 4.56 
               
               
                   
                 FIG. 14A 
               
               
                   
                 AQ 
                 2.20 
               
               
                   
                 AR 
                 4.94 
               
               
                   
                 AS 
                 0.35 
               
               
                   
                 AT 
                 0.29 
               
               
                   
                 FIG. 15 
               
               
                   
                 AU 
                 0.18 
               
               
                   
                 AV 
                 0.10 
               
               
                   
                 FIG. 18A 
               
            
           
           
               
               
               
               
            
               
                   
                 AW 
                 136.0 
                 degrees 
               
               
                   
                 AX 
                 120.0 
                 degrees 
               
               
                   
                 AY 
                 90.0 
                 degrees 
               
               
                   
                 AZ 
                 70.0 
                 degrees 
               
               
                   
                 BA 
                 50.0 
                 degrees 
               
               
                   
                 BB 
                 1.5 
                 (radius of curvature) 
               
               
                   
                 BC 
                 1.0 
                 (radius of curvature) 
               
               
                   
                 BD 
                 1.0 
                 (radius of curvature) 
               
               
                   
                 BE 
                 0.5 
                 (radius of curvature) 
               
               
                   
                 BF 
                 1.0 
                 (radius of curvature) 
               
               
                   
                   
               
            
           
         
       
     
     The curved portion  124  of the optical member  120  has a thickness defined by the inner and outer surfaces  144 ,  136  that varies. The thickness may range from about 3 mm to about 6 mm, preferably from about 3.5 mm to about 5.5 mm, and most preferably from about 4 mm to about 5 mm. Further, the thickness of the optical member  120  at the light redirection features  142  may range from about 0.29 in, (7.366 mm) to about 0.40 in. (10.16 mm). The curved portion  124  may have a first thickness adjacent to the indentation  138  and a second thickness greater than the first thickness adjacent to the light redirection feature  142 . The optical member  120  illustrated in  FIGS.  11 - 16    may exhibit an optical efficiency of at least about 70%, preferably at least about 80%, and most preferably at least about 89%. 
     The overall result, when the LED package  52  is energized, is to produce a desired illumination distribution  172 , for example, as illustrated by the simulation illumination diagrams of  FIGS.  19 A and  19 B .  FIG.  19 A  illustrates a first distribution  172   a  produced along a first plane on which the major axis  130  lies and is perpendicular to the minor axis  132  and a second distribution  172   b  produced along a second plane parallel to the base  126  on which both of the major and minor axes  130 ,  132  lie.  FIG.  19 B  illustrates sample distributions  172  produced along the second plane at various mounting heights. Such distributions may also depend on other parameter(s) such as lumen output. For example, as shown in  FIG.  19 B , the luminaire  50  utilizing the optical member  120  and having a lumen output of about 3, 100 lumens may generate about 0.2 foot-candles, about 0.5 foot-candles, and about 1.0 foot-candles of light having first, second, and third distributions  172   c ,  172   d ,  172   e , respectively, at mounting heights of about 56.25 feet, about 26.25 feet, and about 15 feet, respectively. The distribution of  FIG.  19 B  includes a first extent  174  along an x-axis  176  and a second extent  178  shorter than the first extent  174  along ay-axis  180  perpendicular to the x-axis  176 . 
     Any of the embodiments disclosed herein may include a power circuit having a buck regulator, a boost regulator, a buck-boost regulator, a SEPIC power supply, or the like, and may comprise a driver circuit as disclosed in U.S. patent application Ser. No. 14/291,829, filed May 30, 2014, entitled “High Efficiency Driver Circuit with Fast Response” by Hu et al. (Cree docket no. P2276US1, attorney docket no. 034643-000618) or U.S. patent application Ser. No. 14/292,001, filed May 30, 2014, entitled “SEPIC Driver Circuit with Low Input Current Ripple” by Hu et al. (Cree Docket no. P2291 US1, Attorney Docket No. 034643-000616) incorporated by reference herein. The circuit may further be used with light control circuitry that controls color temperature of any of the embodiments disclosed herein in accordance with viewer input such as disclosed in U.S. patent application Ser. No. 14/292,286, filed May 30, 2014, entitled “Lighting Fixture Providing Variable CCT” by Pope et al. (Cree Docket No. P2301US1) incorporated by reference herein. 
     Further, any of the embodiments disclosed herein may be used in a luminaire having one or more communication components forming a part of the light control circuitry, such as an RF antenna that senses RF energy. The communication components may be included, for example, to allow the luminaire to communicate with other luminaires and/or with an external wireless controller, such as disclosed in U.S. patent application Ser. No. 13/782,040, filed Mar. 1, 2013, entitled “Lighting Fixture for Distributed Control” or U.S. Provisional Application No. 61/932,058, filed Jan. 27, 2014, entitled “Enhanced Network Lighting” both owned by the assignee of the present application and the disclosures of which are incorporated by reference herein. More generally, the control circuitry includes at least one of a network component, an RF component, a control component, and a sensor. The sensor, such as a knob-shaped sensor, may provide an indication of ambient lighting levels thereto and/or occupancy within the room or illuminated area. Such sensor may be integrated into the light control circuitry. 
     INDUSTRIAL APPLICABILITY 
     In summary, the disclosed luminaire provides an aesthetically pleasing, sturdy, cost effective lighting assembly for use in lighting a large area such as a parking lot or deck of a parking garage and/or along a roadway. The lighting is accomplished with reduced glare as compared to conventional lighting systems. 
     The light redirection features and indentation disclosed herein efficiently redirect light out of the optic. At least some of the luminaires disclosed herein are particularly adapted for use in outdoor or indoor general illumination products (e.g., streetlights, high-bay lights, canopy lights, parking lot or parking structure lighting, yard or other property lighting, rural lighting, walkway lighting, warehouse, store, arena or other public building lighting, or the like). According to one aspect the luminaires disclosed herein are adapted for use in products requiring a total lumen output of between about 1,000 and about 12000 lumens or higher, and, more preferably, between about 4,000 and about 10,000 lumens and possibly higher, and, most preferably, between about 4,000 and about 8,000 lumens. According to another aspect, the luminaires develop at least about 2000 lumens. Further, efficacies between about 75 and about 140 lumens per watt, and more preferably between about 80 and about 125 lumens per watt, and most preferably between about 90 and about 120 lumens per watt can be achieved. Still further, the luminaires disclosed herein preferably have a color temperature of between about 2500 degrees Kelvin and about 6200 degrees Kelvin, and more preferably between about 2500 degrees Kelvin and about 5000 degrees Kelvin, and most preferably between about 3500 degrees Kelvin and about 4500 degrees Kelvin. Further, the optical efficiency may range from about 70% to about 95%, most preferably from about 80% to about 90%. A color rendition index (CRI) of between about 70 and about 80 is preferably attained by at least some of the luminaires disclosed herein, with a CRI of at least about 70 being more preferable. Any desired particular output light distribution, such as a butterfly light distribution, could be achieved, including up and down light distributions or up only or down only distributions, etc. 
     When one uses a relatively small light source which emits into a broad (e.g., Lambertian) angular distribution (common for LED-based light sources), the conservation of etendue, as generally understood in the art, requires an optical system having a large emission area to achieve a narrow (collimated) angular light distribution. In the case of parabolic reflectors, a large optic is thus generally required to achieve high levels of collimation. In order to achieve a large emission area in a more compact design, the prior art has relied on the use of Fresnel lenses, which utilize refractive optical surfaces to direct and collimate the light. Fresnel lenses, however, are generally planar in nature, and are therefore not well suited to re-directing high-angle light emitted by the source, leading to a loss in optical efficiency. In contrast, in the present invention, light is coupled into the optic, where primarily TIR is used for re-direction and collimation. This coupling allows the full range of angular emission from the source, including high-angle light, to be redirected and collimated, resulting m higher optical efficiency in a more compact form factor. 
     In at least some of the present embodiments, the distribution and direction of light within the optical member is better known, and hence, light is controlled and extracted in a more controlled fashion. 
     All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
     The use of the terms “a” and “an” and “the” and similar references in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the disclosure and does not pose a limitation on the scope of the disclosure unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosure. 
     Numerous modifications to the present disclosure will be apparent to those skilled in the art in view of the foregoing description. Preferred embodiments of this disclosure are described herein, including the best mode known to the inventors for carrying out the disclosure. It should be understood that the illustrated embodiments are exemplary only, and should not be taken as limiting the scope of the disclosure.