Patent Publication Number: US-9851490-B2

Title: Light guide for low profile luminaire

Description:
RELATED APPLICATIONS 
     This application is a continuation and claims the benefit under 35 U.S.C. §120 of U.S. patent application Ser. No. 15/248,769 titled Light Guide for Low Profile Luminaire, and filed on Aug. 26, 2016, which is, in turn, a continuation-in-part and claims the benefit of U.S. patent application Ser. No. 14/863,150, now U.S. Pat. No. 9,435,930 titled Low Profile Luminaire And Associated Systems And Methods filed Sep. 23, 2015, which is, in turn, a continuation of U.S. patent application Ser. No. 14/014,512, now U.S. Pat. No. 9,157,581 titled Low Profile Luminaire With Light Guide And Associated Methods filed Aug. 30, 2013, which is, in turn, a continuation-in-part of U.S. patent application Ser. No. 13/476,388, now U.S. Pat. No. 8,672,518 titled Low Profile Light and Accessory Kit For The Same filed May 21, 2012, which is, in turn, a continuation-in-part of U.S. patent application Ser. No. 12/775,310, now U.S. Pat. No. 8,201,968 titled Low Profile Light filed May 6, 2010, which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/248,665 filed Oct. 5, 2009, the entire contents of each of which are incorporated herein by reference, except to the extent that any disclosure herein conflicts with the disclosure therein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to low profile luminaires and, more specifically, to luminaires that employ light guides, and associated systems and methods. 
     BACKGROUND 
     Recessed light fixtures (also known as “canister” fixtures) and flush-mount electrical boxes (also known as “junction” boxes) are commonly used in indoor and outdoor downlight applications. Examples of industry standard can-canister fixtures are illustrated as fixture  800  at  FIG. 8  and fixture  900  at  FIG. 9 . Examples of industry standard junction boxes are illustrated as boxes  1000 ,  1100 , and  1200  at  FIGS. 10, 11, and 12 , respectively. Both canister fixtures and junction boxes may be installed in a hollow opening in a ceiling or other surface. Canister fixtures commonly feature a lamp socket configured to receive an incandescent lamp or compact fluorescent lamp (“CFL”). 
     Both incandescent and fluorescent lamp types suffer from certain disadvantages. For example, incandescent lamps convert approximately 3% of electrical power consumed into usable light, while the remaining 97% of power may be wasted as heat. Compared to an incandescent lamp, a fluorescent lamp converts electrical power into useful light more efficiently, delivers a significantly longer useful life, and presents a more diffuse and physically larger light source. However, fluorescent lamps are typically more expensive to install and operate than an incandescent lamp because of the requirement for a ballast to regulate the electrical current. Many fluorescent lamps have poor color temperature, resulting in a less aesthetically pleasing light. Also, if a fluorescent lamp that uses mercury vapor is broken, a small amount of mercury (classified as hazardous waste) can contaminate the surrounding environment. 
     Digital lighting technologies such as light-emitting diodes (LEDs) offer significant advantages over legacy lamps. These advantages include, but are not limited to, better lighting quality, longer operating life, and lower energy consumption. Consequently, LED-based lamps increasingly are being used not only in original product designs, but also in products designed to replace legacy lamps in conventional lighting applications such as canister-based downlights. However, a number of installation challenges and costs are associated with replacing traditional lamps with LED illumination devices. The challenges, which are understood by those skilled in the art, include light output, thermal management, and ease of installation. The costs, which are similarly understood by those skilled in the art, typically stem from a need to replace or reconfigure a canister fixture configured to support traditional lamps to support LEDs instead. 
     By the very nature of their design and operation, LEDs have a directional light output. Consequently, employing LEDs to produce light distribution properties approximating or equaling the light dispersion properties of traditional lamps may require the costly and labor-intensive replacement or reconfiguration of the host light fixture, and/or the expensive and complexity-introducing design of LED-based solutions that minimize the installation impact to the host light fixture. Often material and manufacturing costs are lost in this trade off. Also, light distribution design choices such as large parabolic reflectors and multiple optics operate contrary to the objective of presenting a low profile lighting device as fully assembled. 
     Another challenge inherent to operating LEDs is heat. Thermal management describes a system&#39;s ability to draw heat away from an LED. Passive cooling technology, such as a heat sink thermally coupled to a digital device, may be used to transfer heat from a solid material to a fluid medium such as, for example, air. LEDs suffer damage and decreased performance when operating in high-heat environments. Moreover, when operating in a high-temperature ambient environment and/or a space-limited enclosure, the heat generated by an LED and its attending circuitry can cause damage to the LED. Heat sinks are well known in the art and have been effectively used to provide cooling capacity, thus maintaining an LED-based lamp within a desirable operating temperature. However, heat sinks can sometimes negatively impact the light distribution properties of lighting solution, resulting in non-uniform distribution of light about the fixture. Heat sink designs also may add to the weight and/or profile of an illumination device, thereby complicating installation, and also may limit available space for other components needed for delivering light. 
     Replacement of legacy lighting solutions may be complicated by the need to adapt LED-based devices to meet legacy form standards. For example, in a commercial lighting system retrofit, disposal of a replaced lamp&#39;s fixture housing often is impractical. Consequently, retrofit canister downlights often are designed to adapt to a legacy housing, both functionally and aesthetically. Also, power supply requirements of LED-based lighting systems can complicate installation of LEDs as a retrofit to existing light fixtures. LEDs are low-voltage light sources that require constant DC voltage or current to operate optimally, and therefore must be carefully regulated. Too little current and voltage may result in little or no light. Too much current and voltage can damage the light-emitting junction of the LED. LEDs are commonly supplemented with individual power adapters to convert AC power to the proper DC voltage, and to regulate the current flowing through during operation to protect the LEDs from line-voltage fluctuations. The lighting industry is experiencing advancements in LED applications, some of which may be pertinent to improving the design of low profile canister downlighting solutions. 
     U.S. Pat. No. 7,178,946 to Saccomanno et al. discloses a luminaire device that includes a tubular fluorescent bulb that is partially surrounded on an underside by a curved reflector. Light rays from the bulb are directed towards the curved reflector and reflected towards a collimator. A light guide featuring a refractive slab captures the light output from the collimator and redirects the light away from the device in a uniform luminance. However, employing legacy lamp technology may result in a design that suffers light losses (both to reflection and to absorption). 
     U.S. Pat. No. 8,328,406 to Zimmerman is directed to an illumination system that employs a discrete light source, a reflector, and first and second substantially flat light guides. This lighting solution requires embedding the discrete light source, such as an LED, into a centrally-located region in the second light guide. Light emitted from the light source enters and propagates to the edge of the second light guide, where the reflector reflects light emerging from the edge of the second light guide back into the edge of the first light guide. Optical elements that increase in density from the edge to the center of the first light guide redirect the light to emit at a substantially uniform intensity from the surface of the first light guide. However, sandwiching a light-confining interface layer between multiple light guides operates contrary to the objectives of constructing a low profile luminaire and minimizing design and manufacturing complexity. 
     U.S. Pat. No. 6,647,199 to Pelka at al. discloses a low profile lighting apparatus that includes a light guide coupled to a light source for injecting light into the light guide. In one embodiment, multiple light sources surrounded by diffusive reflective material may introduce light at spaced peripheral locations along the edge of a rectangularly-shaped light guide. However, because the majority of light injected into the edge of the light guide originates from directional-light generating LEDs, a complex plurality of display elements must be designed into the light guide to shape light propagating through the light guide into a substantially uniform illumination profile. 
     Accordingly, and with the above in mind, a need exists for a low profile luminaire that may be employed within the volume of space available in an existing canister light fixture, and that efficiently delivers improved lighting quality compared to traditional lamps. More specifically, a need exists for a canister-based lighting solution that may benefit from the advantages of digital lighting technology, while exhibiting a more uniform illumination profile than legacy downlight solutions. Additionally, a need exists for a luminaire designed for ease of installation as well as for manufacturing cost reduction. 
     This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention. 
     SUMMARY OF THE INVENTION 
     A luminaire comprising a heat sink, a light source and a light guide. The light source may be carried by the heat sink and configured to emit a source light. The light source may include a heat spreader having an inner surface and an outer surface, and a plurality of light-emitting diodes (LEDs) carried by a circuit board and disposed generally along an outer peripheral perimeter portion of the inner surface of the heat spreader, and positioned in thermal communication with the heat spreader. The light guide may include a lens with a plurality of optical elements disposed within the lens. 
     In some embodiments, the plurality of optical elements may be micro-lenses and the micro lenses may be configured to scatter light in more than one direction. The micro-lenses may also be configured to concentrate light in more than one direction. 
     In other embodiments, the plurality of optical elements may be liquid filled or gas filled and still in other embodiments the plurality of optical elements may be one of plastic and glass. Furthermore, the luminaire may include a combination of the light source and the heat sink dimensioned so as to cover an opening defined by a nominally sized four-inch can light fixture, and to cover an opening defined by a nominally sized four-inch electrical junction box. 
     In another embodiment, the luminaire may include a heat sink, a light source and a light guide. The light source may be carried by the heat sink and configured to emit a source light. The light source includes a heat spreader having an inner surface and an outer surface, and a plurality of light-emitting diodes (LEDs) carried by a circuit board and disposed generally along an outer peripheral perimeter portion of the inner surface of the heat spreader, and positioned in thermal communication with the heat spreader. The light guide may include a lens with a plurality of optical elements including light scattering particles disposed within the lens. The light scattering particles may be one of glass, ceramic, rubber, silica, inorganic material, and phosphor. Furthermore, the plurality of optical elements may be one of circular, oval, rectangular, square, and polygonal in shape. 
     In other embodiments, the plurality of optical elements may be micro-lenses and the micro-lenses may be configured to scatter light in more than one direction or may be configured to concentrate light in more than one direction. This embodiment may also include a combination of the light source and the heat sink dimensioned so as to cover an opening defined by a nominally sized four-inch can light fixture, and to cover an opening defined by a nominally sized four-inch electrical junction box. 
     In yet another embodiment, the luminaire may include a heat sink, a light source and a light guide. The light source may be carried by the heat sink and configured to emit a source light. The light source may include a heat spreader having an inner surface and an outer surface, and a plurality of light-emitting diodes (LEDs) carried by a circuit board and disposed generally along an outer peripheral perimeter portion of the inner surface of the heat spreader, and positioned in thermal communication with the heat spreader. The light guide may include a propagation region including a lens with solid optical elements including light scattering particles made from at least one of glass, ceramic, rubber, silica, inorganic material, and phosphor material, and non-solid optical elements comprising liquid and gas. In this embodiment, the lens may include a plurality of micro-lenses and the light guide may be configured to scatter and concentrate light in multiple directions. The micro-lenses may be one of circular, oval, rectangular, square, and polygonal in shape. 
     In this embodiment, a combination of the light source and the heat sink may be so dimensioned as to cover an opening defined by a nominally sized four-inch can light fixture, and sized to cover an opening defined by a nominally sized four-inch electrical junction box. Furthermore, a combination of the light source and the heat sink may also be so dimensioned as to cover an opening defined by a nominally sized four-inch can light fixture, and sized to cover an opening defined by a nominally sized four-inch electrical junction box. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is an assembled, perspective bottom view of a low profile luminaire according to an embodiment of the present invention. 
         FIG. 1B  is an exploded perspective view of the low profile luminaire illustrated in  FIG. 1A . 
         FIG. 1C  is an assembled, front elevation view of the low profile luminaire illustrated in  FIG. 1A . 
         FIG. 1D  is an assembled, cross-sectional view of the low profile luminaire illustrated in  FIG. 1A  and taken through line  1 D- 1 D of  FIG. 1C . 
         FIG. 2  is a schematic cross-sectional view of an exemplary illumination assembly of a low profile luminaire according to an embodiment of the present invention. 
         FIG. 3A  is a perspective bottom view of a heat sink of the low profile luminaire depicted in  FIG. 1B . 
         FIG. 3B  is a perspective top view of the heat sink depicted in  FIG. 3A . 
         FIG. 4A  is a perspective inner view of a light source of the low profile luminaire depicted in FIG. B. 
         FIG. 4B  is a perspective outer view of the light source depicted in  FIG. 4A . 
         FIG. 5  is an assembled, perspective top view of the low profile luminaire depicted in  FIG. 1A . 
         FIG. 6  is a schematic block diagram of a low profile luminaire according to an embodiment of the present invention. 
         FIG. 7  is a flow chart detailing methods of assembling a low profile luminaire according to an embodiment of the present invention. 
         FIGS. 8-12  depict isometric views of canister-type light fixtures and electrical junction boxes according to the prior art for use in accordance with an embodiment of the present invention. 
         FIG. 13  is a top view of a light guide a low profile luminaire according to an embodiment of the present invention. 
         FIG. 14  a side view of the light guide depicted in  FIG. 13 . 
         FIG. 15  is a cross-section view of the light guide of  FIG. 14  along the section A-A in  FIG. 14 . 
         FIG. 16  is a magnified portion of the cross-section view of the light guide of  FIG. 15 . 
         FIG. 17  is a block diagram representation of a machine in the example form of a computer system according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Those of ordinary skill in the art realize that the following descriptions of the embodiments of the present invention are illustrative and are not intended to be limiting in any way. Other embodiments of the present invention will readily suggest themselves to such skilled persons having the benefit of this disclosure. Like numbers refer to like elements throughout. 
     Although the following detailed description contains many specifics for the purposes of illustration, anyone of ordinary skill in the art will appreciate that many variations and alterations to the following details are within the scope of the invention. Accordingly, the following embodiments of the invention are set forth without any loss of generality to, and without imposing limitations upon, the claimed invention. 
     In this detailed description of the present invention, a person skilled in the art should note that directional terms, such as “above,” “below,” “upper,” “lower,” and other like terms are used for the convenience of the reader in reference to the drawings. Also, a person skilled in the art should notice this description may contain other terminology to convey position, orientation, and direction without departing from the principles of the present invention. 
     Furthermore, in this detailed description, a person skilled in the art should note that quantitative qualifying terms such as “generally,” “substantially,” “mostly,” and other terms are used, in general, to mean that the referred to object, characteristic, or quality constitutes a majority of the subject of the reference. The meaning of any of these terms is dependent upon the context within which it is used, and the meaning may be expressly modified. 
     Referring now to  FIGS. 1A-13 , a low profile luminaire  100  according to an embodiment of the present invention is now described in detail. Throughout this disclosure, the present invention may be referred to as a luminaire  100 , a lighting system, an LED lighting system, a lamp system, a lamp, a device, a system, a product, and a method. Those skilled in the art will appreciate that this terminology is only illustrative and does not affect the scope of the invention. For instance, the present invention may just as easily relate to lasers or other digital lighting technologies. 
     Example systems and methods for a low profile luminaire are described herein below. In the following description, for purposes of explanation, numerous specific details are set forth to provide a thorough understanding of example embodiments. It will be evident, however, to one of ordinary skill in the art that the present invention may be practiced without these specific details and/or with different combinations of the details than are given here. Thus, specific embodiments are given for the purpose of simplified explanation and not limitation. 
     Referring now to  FIGS. 1A, 1B, 1C, and 1D , a low profile luminaire  100  configured to be carried by a light fixture (such as the fixture types illustrated, for example, in  FIGS. 8-12 ) will now be discussed. Referring more specifically to  FIGS. 1A and 1B , the luminaire  100 , according to an embodiment of the present invention, may include a heat generating element  110  in the form of a light source, a heat sink  120  thermally coupled to and disposed diametrically outboard of the light source  110 , a reflector  130  in optical communication with and disposed diametrically inboard of the light source  110 , and a light guide  140  positioned in optical communication with at least one of the light source  110  and the reflector  130  and disposed therebetween. Additionally, the luminaire  100  may further include a mounting bracket  122 , a gap pad  112 , a mounting ring  150 , and a trim cover  152 . 
     Although luminaire  100  is depicted as circular in shape in  FIGS. 1A-1D , luminaire  100  and its constituent components may have any of a variety of other shapes, including quadrilateral or polygonal. Regardless of the shape of the luminaire  100 , light may be emitted from the light source  110  and reflected by reflector  130  into the light guide  140  about substantially the entire perimeter of the light guide  140 . The light guide  140  may after the light to project a uniform illuminance into the environment exterior to the luminaire  100 . One or more of the components comprising the luminaire  100  may be connected by any means or method known in the art, including, not by limitation, use of adhesives or glues, welding, interference fit, and fasteners  158 . Alternatively, one or more components of the luminaire  100  may be molded during manufacturing as an integral part of the luminaire  100 . 
     Referring now to  FIGS. 3A and 3B , and continuing to refer to  FIGS. 1A and 1B , the heat sink  120  of the luminaire  100 , according to an embodiment of the present invention, is discussed in greater detail. Thermal management capability of the luminaire  100  according to an embodiment of the present invention may be provided by a heat sink  120 . Although a single heat sink  120  is depicted in the appended figures, those skilled in the art will appreciate that more than one heat sink may be provided while still accomplishing the goals, features and objectives of the present invention. 
     The heat sink  120  may be configured to be thermally coupled to one or more components of the luminaire  100  so as to increase the thermal dissipation capacity of the luminaire  100 . The heat sink  120  may have a bottom surface (illustrated, for example, in  FIG. 3A ) and a top surface (illustrated, for example, in  FIG. 3B ). The heat sink  120  may include a base  312  configured to communicate thermally with the heat generating element  110 , and a sidewall  314  configured to provide a larger surface area than otherwise may be provided by surfaces of the heat generating element  110  and the base  312 . 
     Referring again to  FIG. 1C , the heat sink  120  may be characterized by the sidewall  314  having an overall outside height H and the base  312  having an overall outside dimension D such that the ratio of H/D is equal to or less than 0.25. Although a ratio of 0.25 or less of H/D is preferred, those skilled in the art will appreciate that the present invention contemplates a ratio of greater than 25 of H/D as well. Dimensions for H and D are contemplated such that the heat sink  120  may be configured and sized so as to (i) cover an opening defined by an industry standard can-type light fixture having nominal sizes from three to six inches (see fixture  800  at  FIG. 8  and fixture  900  at  FIG. 9 , for example), and (ii) cover an opening defined by an industry standard electrical junction box having nominal sizes from three to six inches (for example, see boxes  1000 ,  1100 , and  1200  at  FIGS. 10, 11, and 12 , respectively). The base  312  of the heat sink  120  may be configured into any shape, including a circle, ovoid, square, rectangle, triangle, or any other polygon. For example, and without limitation, the heat sink  120  illustrated in  FIGS. 3A and 3B  demonstrates a circular configuration. Also for example, and without limitation, the base  312  and the sidewall  314  may be integrally molded to form the heat sink  120  as a monolithic unit. 
     The sidewall  314  of the heat sink  120  may be in the form of one or more rims. For example, and without limitation, portions of a heat sink  120  may include one or more rims  314  that may be coupled with and positioned substantially perpendicular to the base  312 , the combination of which may form a recess  316 . In the embodiment of the invention illustrated in  FIGS. 3A and 3B , the rim  314  may be configured to define an outer perimeter of the heat sink  120  and to project radially outward from the bottom surface of the generally annular base  312 . For example, and without limitation, the single rim  314  may define a curved frame that may advantageously provide additional surface area to support dissipation of heat. Those skilled in the art will appreciate, however, that the present invention contemplates the use of rims  314  of any shape, and that the disclosed heat sink  120  that includes rims  314  that form a curved frame is not meant to be limiting in any way. 
     Continuing to refer to  FIG. 3B , a top surface  320  of the heat sink  120  may include one or more channels  326 . For example, and without limitation, the rim  314  may comprise an inner wall  322  and an outer wall  324  that, in combination, may form the hollow channel  326 . Employment of the channel  326  may increase the surface area of the heat sink  120  and may permit thermal fluid flow between adjacent inner and outer walls  322 ,  324 , thereby enhancing the heat transfer capability of the heat sink  120 . For example, and without limitation, the rim  314  may have a shape that may promote localized air movement within the one or more channels  326  due at least in part to localized air temperature gradients and resulting localized air pressure gradients. 
     Without being held to any particular theory, it is contemplated that the channel  326  having a narrow end and an opposing broad end may generate localized air temperatures in the narrow end that are higher than localized air temperatures in the associated broad end, due to the difference of proximity of the inner and outer walls  322 ,  324  of the associated channel. More specifically, the width of the channel  326  (measured from the inner wall  322  to the outer wall  324  of rim  314 , and along a plane parallel with the plane defined by the base  312 ) may decrease in a radial direction from the plane of the base  312  to the intersection of the inner and outer walls  322 ,  324 . The presence of such air temperature gradients, with resulting air pressure gradients, within a given channel  326  may cause localized air movement within the associated void, which in turn may enhance the overall heat transfer of the thermal system (the thermal system being the luminaire  100  as a whole). Those skilled in the art will readily appreciate, however, that the rims  314  of the heat sink  120  may be configured in any way while still accomplishing the many goals, features and advantages according to the present invention. 
     Still referring to  FIG. 3B , the channel  326  may be configured to have spatial characteristics permitting fluid flow within the channel  326 . For example, and without limitation, the fluid flow within the channel  326  may cause the transfer of heat from the light source  110  through the base  312  of the heat sink  120 , which may then transfer the heat to the rims  314  and subsequently to the environment either internal or external to the luminaire  100  where the heat may dissipate. Accordingly, the spatial characteristics of the channel  326  may directly correspond to the amount of heat that can be transported from the luminaire  100  to the dissipating environment. Spatial characteristics that can be modified may include total volume, fluid flow characteristics, interior surface area, and exterior surface area. For example, and without limitation, one or more surfaces of the heat sink  120  may be textured or include grooves to increase the surface area of the heat sink  120 , thereby facilitating thermal transfer thereto. Moreover, thermal properties of the materials used to form the heat sink  120  may be considered in forming the thermal management system for the luminaire  100 . 
     The aforementioned spatial characteristics may be modified to accommodate the heat generated by the light source  110  of the luminaire  100 . For instance, the volume of the channel  326  may be directly proportional to the thermal output of the luminaire  100 . Similarly, a surface area of some part of the heat sink  120  may be proportional to the thermal output of the luminaire  100 . In any case, the channel  326  may be configured to maintain the temperature of the luminaire  100  at thermal equilibrium or within a target temperature range. 
     Continuing to refer to  FIG. 3B , the heat sink  120  also may serve as a trim plate for the luminaire  100 . Because canister-type light fixtures and ceiling/wall mount junction boxes are designed for placement behind a ceiling or wall material, the heat sink  120  may be characterized by a substantially flat top surface  320 , thereby permitting the luminaire  100  to sit substantially flush on the surface of the ceiling/wall material. For example, and without limitation, the heat sink  120  may include the channel  326  as described above being V-shaped, thereby causing the heat sink  120  to present a frustoconical shape as illustrated in  FIGS. 1A and 3A . Additionally, in some embodiments, the rim  314  may be configured so as to interface with and/or sit flush on the surface of the ceiling/wall material. 
     The heat sink  120  may be made by molding, casting, or stamping of a thermally conductive material. Materials may include, without limitation, thermoplastic, ceramics, porcelain, aluminum, aluminum alloys, metals, metal alloys, carbon allotropes, and composite materials. Additional information directed to the use of heat sinks for dissipating heat in an illumination apparatus is found in U.S. Pat. No. 7,922,356 titled Illumination Apparatus for Conducting and Dissipating Heat from a Light Source, and U.S. Pat. No. 7,824,075 titled Method and Apparatus for Cooling a Light Bulb, the entire contents of each of which are incorporated herein by reference. 
     Referring now to  FIGS. 2, 4A and 4B , and referring again to  FIG. 1B , the light source  110  of the luminaire  100  according to an embodiment of the present invention is now discussed in greater detail. The light source  110  may comprise one or more light-emitting elements  216 . Each of the light-emitting elements  216  may be any device capable of or method of emitting light. Such devices and methods may include, without limitation, light-emitting semiconductors, lasers, incandescent, halogens, arc-lighting devices, fluorescents, and any other digital light-emitting devices or methods known in the art. In the present embodiment, the light-emitting elements  216  may be light-emitting semiconductors such as, for example, light-emitting diodes (LEDs). 
     In some embodiments of the present invention, the light source  110  may be an LED package. As illustrated in  FIG. 4A , for example, and without limitation, the light source  110  may be an LED package that may include one or more LEDs  216  and a heat spreader  214 . The heat spreader  214  may be a component that completes a heat transfer path from the LEDs  216  to the heat sink  120 , but that does not itself dissipate enough heat from the LEDs  216  to be considered a heat sink. For example, and without limitation, the heat spreader  214  may comprise a printed circuit board. The LEDs  216  may be disposed on and operably coupled to the printed circuit board  214 . The LEDs  216  may be distributed about the inner surface  406  of the printed circuit board  214  in any desirable pattern, configuration, or arrangement. For example, and without limitation, the LEDs  216  may be disposed generally along the periphery of the printed circuit board  214 . Also for example, where the printed circuit board  214  may be divided into two coplanar sections, one section of the printed circuit board  214  may have disposed thereon more LEDs  216  than on the other section. As another example, the LEDs  216  may be distributed about the printed circuit board  214  substantially evenly. The distribution of LEDs  216  on the printed circuit board  214 , and the distribution of light-emitting elements generally, may affect the propagation of light into the recess  316  of the heat sink  120 , the intensity of light incident upon the light guide  140  and, ultimately, the light emission characteristics of the luminaire  100 . Additionally, the LEDs  216  mounted to the printed circuit board  214  may emit light within different wavelength ranges, and the distribution of the LEDs  216  having differing wavelength ranges may similarly affect the light emission characteristics of the luminaire  100 . 
     The printed circuit board  214  of the light source  110  may be sized to couple to the base  312  of the heat sink  120 . In the luminaire  100  presented in an assembled position as illustrated, for example, in  FIG. 1D , the perimeter of the base  312  of the heat sink  120  may be aligned with a respective perimeter of the light source  110 . Therefore, the printed circuit board  214  may generally define the shape of the light source  110  such that the light source  110  may be disposed fittedly in the recess  316  of the heat sink  120 . The printed circuit board  214  may be configured to have a geometric frame configuration substantially as described for the light source  110  described hereinafter. 
     The printed circuit board  214  may be configured to be functionally, electrically, and/or mechanically coupled to the LEDs  216 . The printed circuit board  214  may include necessary circuitry so as to enable the operation of the LEDs  216 . For example, and without limitation, one or more electrical supply lines (not shown) may be disposed in electrical communication with the light source  110 . The printed circuit board  214  may further include electrical contacts  426 . Each of the electrical contacts  426  may be electrically connected to a respective one of the LEDs  216 , thereby enabling the operation of the LEDs  216 . Additionally, the electrical contacts  426  may be configured to interface with and electrically couple to one or more electrical connectors  428  that can supply electrical power from the electrical supply lines to the electrical contacts  426 , thereby enabling the operation of the LEDs  216 . 
     Additionally, the electrical contacts  426  may be configured to enable the selective operation of each of the LEDs  216  by permitting operating signals to be transmitted therethrough. For example, and without limitation, the printed circuit board  214  may include the necessary circuitry so as to enable individual operation of each of the LEDs  216 . Other embodiments of the light source  110  may include light-emitting elements  216  other than LEDs, but may include a structure similar to the printed circuit board  214  that enables the operation of the light-emitting elements  216 . 
     Each of the light-emitting elements  216  may emit light within a wavelength range. More specifically, each of the light-emitting elements  216  may emit light having a wavelength range within the range from about 390 nanometers to about 750 nanometers, commonly referred to as the visible spectrum. Additionally, in some embodiments, the light-emitting elements may emit light having a wavelength within the range from about 200 nanometers to about 390 nanometers, commonly referred to as ultraviolet light. Each of the light-emitting elements  216  may emit light having a wavelength range identical or similar to the wavelength range to another of the light-emitting elements  216 , or it may emit light having a wavelength range different from another of the light-emitting elements  216 . The selection of light-emitting elements  216  included in the light source  110  may be made so as to produce a desirous combined light, as described hereinabove. Accordingly, the light source  110  may include light-emitting elements  216  that produce light having a variety of wavelengths such that the emitted light combines to form a combined polychromatic light. In some embodiments, the combined light may be observed by an observer in the environment external the luminaire  100  as a generally white light. 
     Moreover, the combined light may have desirous characteristics, such as certain color temperatures and color rendering indices. The methods of forming such a combined light are discussed in the references incorporated by reference hereinabove. For example, the light source  110  may include light-emitting elements  216  that emit light that combines to produce a combined light that is generally white in color or any other color such as those represented on the 1931 CIE color space, having a color temperature within the range from about 2,000 Kelvin to about 25,000 Kelvin, and/or having a coloring rendering index within the range from about 15 to about 100. Moreover, in addition to including light-emitting elements  216  to produce a combined light having desirous characteristics, the luminaire  100  may include one or more color conversion layers configured to convert light from a first source wavelength to a second converted wavelength as described in greater detail hereinabove and hereinbelow. 
     Continuing to refer to  FIGS. 1B and 4B , the heat sink  120  may be positioned adjacent an outer surface  424  of the heat spreader  214  of the light source  110 , and may be thermally coupled to the light source  110 . Optionally, a gap pad  112  may be positioned between the heat sink  120  and the outer surface  424  of the light source  110 . Thermal coupling may be accomplished by any method, including thermal adhesives, thermal pastes, thermal greases, thermal pads, and all other methods known in the art. Where a thermal adhesive, paste, or grease is used, the heat sink  120  may be connected to any part of the light source  110  as may effectively cause thermal transfer between the light source  110  and the heat sink  120 . The method of thermal coupling may be selected based on criteria including ease of application/installation, thermal conductivity, chemical stability, structural stability, and constraints placed by the luminaire  100 . 
     Connection point locations for one or more LEDs  216  may depend at least partially on the heat distribution within the light source  110 . For example, the heat sink  120  may be thermally coupled directly to one or more LEDs  216 , indirectly to the LEDs  216  which may be thermally coupled to the heat spreader  214 , or both. As described above, the heat spreader  214  may be in the form of a printed circuit board. In application, the LED package may generate heat at the junction of each LED die  216 . To provide for suitable heat transfer from the LEDs  216  to the heat sink  110 , an embodiment may employ a plurality of interconnecting threads  426  which provide suitable surface area for heat transfer thereacross. 
     For example, and without limitation, the substantially flat base  312  of the heat sink  120  (as illustrated in  FIG. 3A ) may come into thermal contact with the outer surface  424  of the printed circuit board  214  of the light source  110 . The one or more rims  314  of a heat sink  120  may be positioned peripheral to the surface of the base  312  with which the light source  110  makes contact. Accordingly, and as may be understood by those skilled in the art, the heat sink  120  advantageously may provide additional surface area for heat that may be produced by the light source  110  to be dissipated. Additionally, the base  312  of the heat sink  120  also may be configured to make mechanical contact with the outer surface  424  of the light source  110 , thereby providing for the heat sink  120  to carry the light source  110  and/or fixing the orientation of the light source  110  within the luminaire  100  during normal operation. For example, and without limitation, the light source  110  and the base  312  of the heat sink  120  may be configured to have substantially matching shapes, such as a circle (otherwise known as a disk), an oval, a square, a rectangle, a triangle, a regular polygon, and an irregular polygon. 
     Referring again to  FIGS. 1B and 2 , an illumination assembly, which may comprise the light source  110 , the reflector  130 , and the light guide  140 , will now be discussed in more detail. In the present embodiment, the light source  110  may include a reflective layer  218  disposed on the printed circuit board  214  on a surface to which the LEDs  216  may be attached or adjacent to, and in any case the surface of the printed circuit board  214  upon which light emitted by the LEDs  216  may be incident upon. The reflective layer  218  may be positioned so as to cover the inner surface  406  of the printed circuit board  214 , while permitting the one or more LEDs  216  to be uncovered. The reflective layer  218  may efficiently reflect light from the LEDs  120  away from the printed circuit board  214  and toward other luminaire components present in the recess  316 . More specifically, the reflective inner surface  406  of the printed circuit board  214  may reflect light incident thereupon back into the recess  316 , thereby reducing the loss of light that otherwise would not be reflected by the printed circuit board  214 . 
     While  FIG. 2  includes the reflective layer  218 , it will be appreciated that not all embodiments of the invention disclosed herein may employ a reflective layer  218 , and that when a reflective layer  218  is employed it may be used for certain optical preferences and/or to mask other components, such as electronics, that may be positioned opposite the inner surface  406  of the printed circuit board  214  of the luminaire  100 . For example, and without limitation, the surface of the reflective layer  218  may be white, reflective polished metal, or metal film over plastic, and may have surface detail for certain optical effects, such as color mixing or controlling light distribution and/or focusing. 
     The light source  110  may be desirously positioned within the luminaire  100 . For example, and without limitation, the light source  110  may be positioned within the luminaire  100  such that light that propagates through complementary components of the luminaire  100  and into the environment surrounding the luminaire  100  is generally controlled. As a further example, the light source  110  may be positioned such that the light source  110  is not visible from any point in the environment external the luminaire  100 , the environment generally defined as a hemisphere beneath the heat sink  120 . Similarly, the light source  110  may be positioned such that light emitted from the light source  110  is not directly observable from any point in the environment external the luminaire  100 . For example, any light that is visible from a point in the environment external the luminaire  100  may be reflected at least once, such as light that is reflected from the reflective layer  218 . 
     Referring again to  FIGS. 1B and 2 , the reflector  130  of the luminaire  100  according to an embodiment of the present invention is now discussed in greater detail. The reflector  130  may have an interior region configured for receiving light from the light source  110 . For example, and without limitation, light emitted by one or more LEDs  216  may be incident upon the interior region of the reflector  120 . In a preferred embodiment, one or more LEDs  216  present in the light source  110  may be positioned to emit light in a direction that may be at an angle not perpendicular to the orientation of the interior region of the reflector  130 . 
     The reflector  130  may be formed into any geometric configuration so as to position the interior region generally coextensive with the positioning of the one or more LEDs  216 . In the present embodiment, the reflector  130  is formed into a generally annular configuration (also known as ring-shaped). More specifically, the reflector  130  may be formed into an annular configuration to define an aperture  132 . The aperture  132  may be configured to permit light traversing the recess  316  to pass therethrough. Furthermore, the aperture  132  may cooperate with additional components of the luminaire  100  to permit the traversal of light from the recess  316  to the environment. 
     The aperture  132  may be a void formed by the reflector  130  somewhere within the periphery of the reflector  130  such that an outer edge of the aperture  132  may define an inner rim of the reflector  130 . In the present embodiment, the aperture  132  may be formed in a medial region of the reflector  130 . Furthermore, the aperture  132  may be configured into any geometric configuration. In the present embodiment, the aperture  132  is generally circular. This embodiment is exemplary only, and the aperture  132  may be formed into any other geometric configuration, including, without limitations, ovals, semicircles, triangles, squares, and any other polygon. 
     Additionally, due to the positioning of the aperture  132  generally at the center of the reflector  130  and due to the aperture  132  being configured as a circle, the reflector  130  may be described as a frame. This embodiment is exemplary only, and the reflector  130  may be formed into any other geometric configuration, including, without limitations, ovals, semicircles, triangles, squares, and any other polygon, with the aperture  132  being formed somewhere within the periphery of the geometric configuration employed. Moreover, the reflector  130  and the aperture  132  may be selectively formed into identical, similar, or entirely different geometric configurations. In forming each of the reflector  130  and the aperture  132 , the geometric configuration of a light fixture in which the luminaire  100  may be disposed may be considered. 
     The reflector  130  may be configured to reflect light incident thereupon. More specifically, the interior region of the reflector  130  may be configured to reflect a light incident thereupon such that the reflected light has an intensity of about 80% to about 99% of the intensity of the light before being reflected. The reflector  130  may be configured to be reflective by any method known in the art. For example, and without limitation, the reflector  130  may be formed of a material that is inherently reflective of light, and therefore a surface upon which emitted light may be incident inherently would be reflective. As another example, the reflector  130  may be formed of a material that may be polished to become reflective. As yet another example, the reflector  130 , or at least an interior region of the reflector  130 , may be formed of a material that is permissive of a material being coated, attached, or otherwise disposed thereupon, the disposed material being reflective. These methods of forming the reflector  130  are exemplary only and do not serve to limit the scope of the invention. All methods known in the art of forming a reflective surface are contemplated and included within the scope of the invention. 
     Continuing to refer to  FIGS. 1B and 2 , the interior region of the reflector  130  may include a color conversion layer  272 . The color conversion layer  272  may be configured to receive a source light within a first wavelength range and convert the source light to a converted light having a second wavelength range. Additionally, the reflector  130  may include two or more color conversion layers  272 , wherein each color conversion layer is positioned upon different sections of the reflector  130 . Each of the two or more color conversion layers  272  may convert respective source lights of differing wavelength ranges to respective converted lights of differing wavelength ranges. The reflector  130  may include any number of color conversion layers  272  in any configuration, including overlapping layers. Color conversion layers  272  may be formed of material selected from the group consisting of phosphors, quantum dots, luminescent materials, fluorescent materials, and dyes. More details regarding the enablement and use of a color conversion layer  272  may be found in U.S. patent application Ser. No. 13/073,805, entitled MEMS Wavelength Converting Lighting Device and Associated Methods, filed Mar. 28, 2011, as well as U.S. patent application Ser. No. 13/234,604, entitled Remote Light Wavelength Conversion Device and Associated Methods, filed Sep. 16, 2011, U.S. patent application Ser. No. 13/234,371, entitled Color Conversion Occlusion and Associated Methods, filed Sep. 16, 2011, and U.S. patent application Ser. No. 13/357,283, entitled Dual Characteristic Color Conversion Enclosure and Associated Methods, the entire contents of each of which are incorporated herein by reference. 
     The reflector  130 , which may be in thermal contact with the light source  110  and, where present, the color conversion layer(s)  272 , may be formed of a thermally conductive material. Forming the reflector  130  of thermally conductive material may increase the thermal dissipation capacity of the luminaire  100  generally. Examples of thermally conductive materials include metals, metal alloys, ceramics, and thermally conductive polymers. This list is not exhaustive, and all other thermally conductive materials are contemplated and within the scope of the invention. 
     Referring again to  FIGS. 1B and 2 , the light guide  140  of the luminaire  100  according to an embodiment of the present invention is now discussed in greater detail. The light-emitting elements  216  may be configured to emit light in a direction so as to propagate into the light guide  140 . More specifically, the light guide  140  may include one or more lens portions  242  that may be positioned at the circumferential edge of the light guide  140  into which light reflected by the reflector  130  may enter the light guide  140 . The light guide  140  also may include a propagation region  244  that may retain and spread light within the propagation region  144  until the light may be emitted substantially uniformly from a projection surface  252  of the light guide  140 . The one or more lens portions  242  may be configured to facilitate coupling and redirecting of the light emitted by the LEDs  216  of the light source  110  into propagation region  244  of the light guide  140 . 
     For example, and without limitation, the projection surface  252  may be defined as the lower boundary of the light guide  140 . The lens portion  242  may redirect reflected light at angles required for the input light to enter and propagate through the propagation region  244  and, ultimately, to pass through multiple points on the projection surface  252  of the light guide  140  at a uniform illuminance. As shown in  FIG. 2 , the reflector  130  may be configured to cooperate with the light source  110  to completely define the region occupied by the light guide  140  within the recess  316  of the heat sink  210 . More specifically, the aperture  132  in the reflector  130  may be substantially coplanar with the projection surface  252  of the light guide  140 . The aperture  132  may be configured so as to cooperate with the projection surface  252  of the light guide  140  to permit light that traverses the projection surface  252  of the light guide  140  to similarly traverse the aperture  132  and to propagate into the environment surrounding the luminaire  100 . Exemplary propagation and projection paths traveled by light emitted from light source  110  are shown in  FIG. 2  as a series of dashed arrows. 
     To facilitate emission of the propagation and/or projection of light, the light guide  140  may include a plurality of optical elements  262  disposed with the lens portion  242 , propagation region  244 , and/or the projection surface  252  of the light guide  140 . Optical elements  262  may operate to scatter light in more than one direction, and such that the scattered light may be emitted through the projection surface  252  of the light guide  140 . Optical elements  262  may include light-scattering particles comprising materials such as, for example and without limitation, glass, ceramic, rubber, silica, inorganic material, and phosphor material. For example, and without limitation, optical elements  262  may comprise non-phosphorescent particles that scatter light without converting the wavelength of the input light. Optical elements  262  also may comprise non-solid objects embedded in the light guide  140 , such as, for example and without limitation, closed liquid-filled and/or gas-filled voids. In some embodiments, optical elements  262  also may comprise micro-lenses and/or other light shaping structures having either diffusing or concentrating properties. 
     In accordance with various embodiments of the invention, the size, type, and/or density of optical elements  262  may be selected to provide illumination that is substantially uniform in intensity across the projection surface  252  of the light guide  140 . For example, and without limitation, the optical elements  262  may be arranged in the form of a plurality of concentric shapes about the center of the light guide  140 . The shapes may be round, ellipsoidal, polygonal, or combinations thereof, and may present as concentric ridges on one or more exterior surfaces of the light guide  140 . Also for example, and without limitation, the density of optical elements  262  may increase from the edge of light guide  110  to the center of the light guide  140 . Varying the density of optical elements  262  in this manner may cause an optical mean free path within the light guide  140  to decrease as a function of distance from the edge of the light guide  140  to the center of the light guide  140 . The diminishing optical mean free path may facilitate an increasing ratio between the emitted portion and propagated portions of the light. The density, size, and/or type of optical elements  262  may increase in discrete steps, resulting in concentric areas containing different densities of optical elements  262 . 
     The positioning of the light source  110  and the light-emitting elements  216  may take into account the direction that light emitted therefrom will propagate through the light guide  140 , as well as any other element or structure of the luminaire  100  with which light may be incident and may interact. For example, and without limitation, the light source  110  and plurality of light-emitting elements  216  may be positioned to take into account the incidence of emitted light upon the reflector  130  and the reflection of the light therefrom. As described hereinabove, light reflected from the reflector  130  may propagate through the light guide  140  and into the environment surrounding the luminaire  100  through the aperture  132  of the reflector  130  in a predictive direction. For example, and without limitation, the light emitted from a light-emitting element  216  may be reflected by the reflector  130 , propagated through the light guide  140 , and projected through the aperture  132  in a direction that is generally in alignment with the longitudinal axis of the luminaire  100 . 
     Light that may escape the light guide  140  and that is incident upon the interior region of the reflector  130  and/or upon the reflective layer  218  may be reflected back into the light guide  140 . For example, and without limitation, the reflective layer  218  of the light source  110  may have reflective properties, such that any reflected light not captured by the lens portion  142  of light guide  140  may be redirected back into light guide  140  via reflection from reflective layer  218 . Such recycled light may propagate back through light guide  140  and eventually be redirected to the projection surface  252 . 
     The light guide  140  may be configured so as to permit light that propagates through the light guide  140  to combine, forming a combined light. The combined light may be a polychromatic light, having multiple constituent wavelengths of light. In some embodiments, the combined light may be a white light. Additional information regarding color combination may be found in U.S. patent application Ser. No. 13/107,928, entitled High Efficacy Lighting Signal Converter and Associated Methods, filed May 15, 2011, as well as U.S. Patent Application Ser. No. 61/643,308, entitled Tunable Light System and Associated Methods, filed May 6, 2012, the entire contents of each of which are incorporated by reference herein. 
     The light guide  140  may be configured into any shape. As depicted in  FIG. 1B , the light guide  140  may be configured into a three-dimensional geometric shape. In the present embodiment, the light guide  140  may have a thin puck-shaped configuration. Many other shapes of the light guide  140  are contemplated and included within the scope of the invention, including, without limitation, spherical, conical, cylindrical, parabolic, pyramidal, and any other geometric configuration that may collimate, concentrate, refract, reflect, convert, and/or diffuse light. The light guide  140  may comprise any material that may change the direction of propagation of light, such as, for example and without limitation, polycarbonate, polymethyl methacrylate (PMMA), polyurethane, amorphous nylon, polymethylpentene, polyvinylidene fluoride (PVDF), or other thermoplastic fluorocarbon polymers. Additionally, the light guide  140  may be formed either as a separate structure from the reflector  130  or as an integral member of the reflector  130 . 
     Referring again to  FIGS. 1B and 5 , the connector components of the luminaire  100  according to an embodiment of the present invention are now discussed in greater detail. More specifically, the luminaire may comprise a mounting ring  150  and a mounting bracket  122 . 
     The mounting ring  150  may be configured to attach, carry, or otherwise become engaged with various components of the luminaire  100 , including one or more of the reflector  130 , the light guide  140 , and the light source  110 . Such engagement with the mounting ring  150  may fix the position of a component with respect to the heat sink  120  within the luminaire  100 . For example, and without limitation, the heat sink  120  may include mounting holes  358  that may align with corresponding threaded holes  156  in the mounting ring  150  for the purpose of receiving fasteners  158  to secure the mounting ring  150  to the heat sink  120 . 
     Additionally, the mounting ring  150  may be positioned in a relationship to the aperture  132  of the reflector  130 . In the present embodiment, the mounting ring  150  may be positioned generally about the aperture  132 . More specifically, the mounting ring  150  may be positioned about the periphery of the aperture  132 , generally circumscribing the aperture  132 . Furthermore, the mounting ring  150  may be positioned so as to result in desirable emission characteristics of the light guide  140  where the light guide  140  may be engaged with the mounting ring  150 . Accordingly, the mounting ring  150  may be positioned in relation to emission characteristics of the light source  110  as well as reflective characteristics of the reflector  130  and/or the projection characteristics of the light guide  140 . 
     Additionally, the mounting ring  150  may be formed into a geometric configuration. In the present embodiment, the mounting ring  150  may be formed into a generally annular frame configuration. This configuration is exemplary only, and the mounting ring  150  may be formed into any geometric formation. Moreover, the mounting ring  150  may be formed into a geometric configuration identical, similar, or different from the geometric configurations of the aperture  132  and/or the reflector  130 . Additionally, the mounting ring  150  may be formed into a geometric configuration so as to facilitate engagement with either of the light source  110  or the light guide  140 , or both. 
     The mounting ring  150  may be configured to add to the thermal dissipation capacity of the luminaire  100 . More specifically, the mounting ring  150  may be configured to maximize the conduction of heat from any component positioned in thermal communication with the mounting ring  150 , such as, for example, the light source  110  and/or the heat sink  120 . Accordingly, the mounting ring  150  may be configured to maximize the surface area of the interface between the mounting ring  150  and the light source  110 , providing that such interfacing does not impede the propagation of light emitted by the light source  110  and/or projected by the light guide  140 . The mounting ring  150  may be formed of any thermally conductive material describe hereinabove. 
     Referring again to  FIG. 3B , and continuing to refer to  FIGS. 1B and 5 , in the present embodiment, the luminaire  100  may include a mounting bracket  122 . Securement of the luminaire  100  to a fixture (see, for example, fixtures  800  and  900  at  FIGS. 8 and 9 , respectively) or to a junction box (see, for example, boxes  1000 ,  1100 , and  1200  at  FIGS. 10, 11, and 12 , respectively) may be accomplished by using a mounting bracket  122  and suitable fasteners (not shown) through appropriately spaced holes  522  in the mounting bracket  122 . Once secured to a host fixture, the mounting bracket  122  may present an alignment hole with an internally-threaded bore that may be configured to receive an Edison connector portion  340 . The Edison connector portion  340  may be formed on the top surface  320  of the heat sink  120  either as a separate structure from the heat sink  120  or as an integral member of the heat sink  120 . More specifically, the Edison connector portion  340  of the heat sink  120  may be configured to be carried by the mounting bracket  122  so as to removably attach the heat sink  120  to a junction box and/or to a canister-type fixture by operation of the mounting bracket  122 . This embodiment is exemplary only and all methods of removable attachment are contemplated and included within the scope of the invention. 
     Referring again to  FIGS. 1A, 1B, and 2 , the outer optic  154  of the present embodiment will now be discussed in greater detail. The outer optic  154  may be configured to be disposed in relation to the light guide  140  such that light projected from the projection surface  252  of the light guide  140  may be incident upon the outer optic  154  and subsequently may pass through the outer optic  154 . For example, and without limitation, the outer optic  154  may be carried by one or more of the mounting ring  150  and the reflector  130 . Also for example, and without limitation, the outer optic  154  may be integrally formed with one or more of the mounting ring  150  and the reflector  130 . 
     Additionally, the outer optic  154  may substantially cover and obscure from view all of the components of the luminaire  100  that may be configured to be carried by the heat sink  120 , thereby advantageously presenting a low-profile and aesthetically pleasing appearance of the luminaire  100 . Referring again to  FIG. 1A , the outer optic  154  may interface with the interior region of the mounting ring  150  so as to form a seal therebetween, shielding the light guide  140  of the light source  110  from the environment surrounding the luminaire  100 . 
     The outer optic  154  may be formed into a geometric configuration that may be generally similar to the geometric configuration of the light guide  140 . In the present embodiment, the outer optic  154  may formed into a circular configuration having a generally flat geometry. This configuration is exemplary only, and the outer optic  154  may be formed into any geometric configuration. The outer optic  154  may be made of a suitable material to facilitate shaping of the light emitted by the light guide  140  to a uniform intensity across the diameter of the outer optic  154 . 
     For example, the outer optic  154  may be configured to interact with light projected by the light guide  140  to refract incident light. The outer optic  154  may be formed in any shape to impart a desired refraction. Furthermore, the outer optic  154  may be formed of any material with transparent or translucent properties that comport with the desired refraction to be performed by the outer optic  154 . Moreover, the outer optic  154  may be formed so as to refract light incident thereupon from the light guide  140  so as to refract the incident light in a desirous direction. Further, the direction of the refraction may result in the propagation of the refracted-reflected light into the environment surrounding the luminaire  100  in a desirous direction. In the present embodiment, the outer optic  154  may include an outer surface having a plurality of approximately orthogonal sections formed therein. The orthogonal sections may be configured to desirously refract light incident thereupon. The structure and use of a refracting optic is described in U.S. Patent Application Ser. No. 61/642,205, entitled Luminaire with Prismatic Optic, filed May 3, 2012, which is incorporated herein by reference. 
     Additionally, in some embodiments, the outer optic  154  may be configured to collimate light incident thereupon, such as light projected from the light guide  140 . Additionally, the outer optic  154  may be configured to generally diffuse, concentrate, and/or reflect light incident thereupon. In some embodiments, the outer optic  154  may include a color conversion layer. The color conversion layer of the outer optic  154  may be configured similarly to the color conversion layer as described hereinabove for the reflective layer  218 . 
     Referring again to  FIGS. 4A, 48, and 5 , the electronics housing of the luminaire  100 , according to an embodiment of the present invention, is discussed in greater detail. 
     The Edison connector portion  340  of the heat sink  120  may have a substantially hollow interior configured to receive various components and circuitry of the luminaire  100 . For example, and without limitation, the Edison connector portion  340  may be configured to contain the power supply (not shown) and other electronic control devices. Also for example, and without limitation, the Edison connector portion  340  may present a cylinder of sufficient diameter to permit wires to pass therethrough from the light source  110  to the power supply. The Edison connector portion  340  also may be configured to connect to an internally-threaded power supply socket. Those skilled in the art will appreciate that an electrical connector for the light source  110  may be provided by any type of connector that is suitable for connecting the light source  110  to a power source. The Edison connector portion  340  of the heat sink  120  may, for example, be integrally molded with the heat sink to form a monolithic unit. Alternatively, the Edison connector portion  340  of the heat sink  120  may be connected to the heat sink by other means such as, for example, an adhesive or welding. Those skilled in the art will appreciate that any connection between the Edison connector portion  340  and the heat sink  120  is contemplated by the present invention. 
     Additional details regarding the Edison connector portion  340  and electronics that may be disposed therein may be found in U.S. patent application Ser. No. 13/676,539 titled Low Profile Light Having Concave Reflector and Associated Methods filed on Nov. 14, 2012, as well as in U.S. patent application Ser. No. 13/476,388 titled Low Profile Light and Accessory Kit For The Same filed on May 21, 2012, in U.S. patent application Ser. No. 12/775,310, now U.S. Pat. No. 8,201,968, titled Low Profile Light filed on May 6, 2010, and in U.S. Provisional Patent Application Ser. No. 61/248,665 filed Oct. 5, 2009, the entire contents of each of which are incorporated herein by reference. 
     Referring now to the schematic representation illustrated in  FIG. 6 , a system  600  for operating a low profile luminaire  100  according to an embodiment of the present invention will now be described in greater detail. The logical components of the luminaire  100  may include a controller  601  and the light source  110 . For example, and without limitation, the light source  110  may comprise a plurality of LEDs  216  each arranged to generate a source light. The controller  601  may be designed to control the characteristics of the combined light emitted by the light source  110 . The controller  601  may execute control program instructions using a processor  602  that may accept and execute computerized instructions, and also a data store  603  which may store data and instructions used by the processor  602 . 
     The controller  601  may be positioned in electrical communication with a power supply so as to be rendered operational. Additionally, the controller  601  may be operably connected to the light source  110  so as to control the operation of the luminaire  100 . The controller  601  may be configured to operate the light source  110  between operating and non-operating states, wherein the light source  110  emits light when operating, and does not emit light when not operating. Furthermore, where the light source  110  includes a plurality of light-emitting elements  216  (as illustrated in  FIG. 4A ), the controller  601  may be operably connected to the plurality of light emitting elements  216 . 
     Yet further, the controller  601  may be operably connected to the plurality of light-emitting elements  216  so as to selectively operate each light-emitting element of the plurality of light-emitting elements  216 . Accordingly, the controller  601  may be configured to operate the light-emitting elements  216  as described hereinabove. Moreover, the controller  601  may be configured to operate the light-emitting elements  216  so as to control the color, color temperature, brightness, and distribution of light produced by the luminaire  100  into the environment surrounding the luminaire  100  as described hereinabove. 
     In addition to selective operation of each light-emitting element of the plurality of light-emitting elements  216 , the controller  601  may be configured to operate each of the plurality of light-emitting elements  216  so as to cause each light-emitting element  216  to emit light either at a full intensity or a fraction thereof. Many methods of dimming, or reducing the intensity of light emitted by a light-emitting element, are known in the art. Where the light-emitting elements  216  are LEDs, the controller  601  may use any method of dimming known in the art, including, without limitation, pulse-width modulation (PWM) and pulse-duration modulation (PDM). This list is exemplary only and all other methods of dimming a light-emitting element is contemplated and within the scope of the invention. Further disclosure regarding PWM may be found in U.S. Pat. No. 8,384,984 titled MEMS Wavelength Converting Lighting Device And Associated Methods, filed Mar. 28, 2011, the entire contents of which are incorporated by reference hereinabove. 
     Continuing to refer to  FIG. 6 , the luminaire  100  may comprise a user interface  604  and/or a sensor  605  configured to program the controller  601  to control the emissions characteristics of the light source  110 . More specifically, the processor  602  may be configured to receive the input transmitted from some number of control devices  604 ,  605  and to direct that input to the data store  603  for storage and subsequent retrieval. For example, and without limitation, the processor  602  may be in data communication with the device  604 ,  605  through a direct connection and/or through a network connection  606  to a network  607 , such as the Internet. 
     Also for example, and without limitation, the network interface  606  of the luminaire  100  may comprise a signal receiver and/or a signal transmitter. The controller  601  may be programmed to selectively operate the light source  110  in response to electronic communication received from an external device  604 ,  605  through the signal receiver. The controller  601  also may be configured to transmit beam characteristics to an external device (such as another luminaire  100 ) through the signal transmitter to a network  607 . More disclosure regarding networked lighting and attending luminaires may be found in U.S. patent application Ser. No. 13/463,020, entitled Wireless Pairing System and Associated Methods, filed May 3, 2012 and U.S. patent application Ser. No. 13/465,921, entitled Sustainable Outdoor Lighting System and Associated Methods, filed May 7, 2012, the entire contents of both of which are incorporated herein by reference. 
     Also for example, and without limitation, the sensor  605  may comprise an occupancy sensor and/or a timer may be employed for automatic selection and communication of beam characteristics to the controller  601 . The sensor  605  may transmit a signal to the controller  601  indicating that the controller  601  should either operate the light source  110  or cease operation of the light source  110 . For example, the sensor  605  may be an occupancy sensor that detects the presence of a person within a field of view of the occupancy sensor  605 . When a person is detected, the occupancy sensor  605  may indicate to the controller  601  that the light source  110  should be operated so as to provide lighting for the detected person. Accordingly, the controller  601  may operate the light source  110  so as to provide lighting for the detected person. 
     Furthermore, the occupancy sensor  605  may either indicate that lighting is no longer required when a person is no longer detected, or either of the occupancy sensor  605  or the controller  601  may indicate lighting is no longer required after a period of time transpires during which a person is not detected by the occupancy sensor  605 . Accordingly, in either situation, the controller  601  may cease operation of the light source  110 , terminating lighting of the environment surrounding the luminaire  100 . The sensor  605  may be any sensor capable of detecting the presence or non-presence of a person in the environment surrounding the luminaire  100 , including, without limitation, infrared sensors, motion detectors, and any other sensor of similar function known in the art. More disclosure regarding motion-sensing lighting devices and occupancy sensors may be found in U.S. patent application Ser. No. 13/403,531, entitled Configurable Environmental Sensing Luminaire, System and Associated Methods, filed Feb. 23, 2012, and U.S. patent application Ser. No. 13/464,345, entitled Occupancy Sensor and Associated Methods, filed May 4, 2012, the entire contents of both of which are herein incorporated by reference. 
     Referring now to  FIG. 7 , a method aspect  700  for assembling a lighting device adapted to be carried by a lighting fixture will now be discussed. From the start  705 , the assembly method  700  may spawn concurrent process paths for simultaneously constructing distinct sections of a luminaire  100  according to an embodiment of the present invention. One path may include the step of forming the heat sink  120  and complementary mounting bracket  122  at Block  710 . Forming the heat sink  120  may include fabricating the base  312  to include the mounting holes  358  designed to receive fasteners  158 . Forming the heat sink  120  may also include forming the Edison connector portion  340  to project radially outward from the top surface  320  of the base  312 , and forming one or more rims  314  to project radially inward from the periphery of the base  312 . The mounting bracket  122  may be formed to threadably receive the exterior of the Edison connector portion  340 . At Block  720 , electronics components may be fixedly installed into a void defined by the interior of the Edison connector portion  340  of the heat sink  120 . Access to the void may be provided by an opening in the Edison connector portion  340  that may be coplanar with the base  312 . At Block  730  the light source  110  may be positioned in electrical communication with a power source, and at Block  740  the light source  110  may be positioned in thermal communication with the heat sink  120 . The orientation of the light source  110  may be such that the inner surface  406  of the printed circuit board  214  that carries one or more LEDs  216  (and, optionally, the reflective layer  218 ) may be opposite the outer surface  424  of the light source  110  in thermal communication with the heat sink  120 . 
     From the start  705 , a second process path may include the step of forming the mounting ring  150  at Block  715 . Forming the mounting ring  150  may include fabricating threaded holes  156  that may be designed to receive fasteners  158 , as well as forming the outer optic  154  in a geometric configuration that may interface with the seating structure of the mounting ring  150 . For example, and without limitation, the outer optic  154  may be integrally formed with the mounting ring  150 . At Block  725 , the light guide  140  may be installed into the reflector  130  by positioning the projection surface  252  of the light guide  140  adjacent the aperture in the reflector  130 , and by orienting the edge of the light guide  140  adjacent the reflective interior portion of the reflector  130 . This assembly may then be inserted into the mounting ring  150  at Block  735 , with the outer portion of the reflector  130  interfacing the seating structure of the mounting ring  150 . 
     At Block  750 , the separate assemblies created using the two process paths described above may be oriented for combination into an operational luminaire  100 . This step may include inserting the assembled light guide  140 , reflector  130 , and mounting ring  150  into the recess in the heat sink  120  such that the light guide  140  is positioned adjacent to the light source  110 . For example, and without limitation, the light guide  140  may be positioned to orient one or more specific LEDs  216  to be in optimal optical communication with one or more of specially-designed reflective regions on the reflector  130 , with specially-designed propagation regions of the light guide  140 , and with specially-designed refractive regions of the outer optic  154 . After all components are properly oriented as described above, these components may be secured at Block  760  by fasteners  158  applied through the mounting holes  358  in the heat sink  120  and into the threaded holes  156  of the mounting ring  150 . At Block  770 , a trim cover  152  may be attached to the mounting ring  150  in a position that may obscure the reflector  130  and/or LEDs  216  of the light source  110  from view from any point external the luminaire  100 . For example, the trim cover  152  may circumferentially snap-fit over the mounting bracket  150  and/or the outer optic  154 . The snap-fit arrangement of the trim cover  152  relative to the outer optic  154  may be such that the trim cover  152  may be removed in a pop-off manner for maintenance or other purposes. 
     To provide for a low profile luminaire  100 , as illustrated in  FIG. 1C , the method  700  may create an assembly of the light source  110 , heat sink  120 , reflector  130 , and light guide  140  that may have an overall outside height H and an overall outside dimension D such that the ratio of H/D is equal to or less than 0.25. Dimensions for H and D are contemplated such that the combination of the light source  110 , heat sink  120 , reflector  130 , and light guide  140  may be configured and sized so as to (i) cover an opening defined by an industry standard can-type light fixture having nominal sizes from three to six inches (see fixture  800  at  FIG. 8  and fixture  900  at  FIG. 9 , for example), and (ii) cover an opening defined by an industry standard electrical junction box having nominal sizes from three to six inches (for example, see boxes  1000 ,  1100 , and  1200  at  FIGS. 10, 11, and 12 , respectively). 
     Referring now to  FIGS. 13, 14, 15, and 16 , additional embodiments of the light guide  140  will now be discussed. As described above, the light guide  140  may include one or more lens portions  242  that may operate to alter light to project a uniform illuminance into the environment exterior to the luminaire  100 . Alternative to, or in addition to, the lens portions  242 , the light guide  140  may be characterized by deformations in one or more exterior surfaces of the light guide  140  that may operate to spread light that is projected into the light guide  140  by the LEDs  216  of the light source  110 . For example, and without limitation, the deformations may include grooves cut into a surface of the light guide  140  opposite the projection surface  252  of the light guide  140 . 
     As shown in the embodiment depicted in  FIG. 13 , the grooves may be shaped as concentric circles  1300  of differing radii. Similar to the function of the lens portions  242  as described above, the deformations  1300  may be configured to facilitate coupling and redirecting of the light emitted by the LEDs  216  of the light source  110  into the propagation region  244  of the light guide  140  and, ultimately, emission of substantially uniform light from the projection surface  252  (see  FIGS. 14, 15, and 16 ). 
     For example, and without limitation, the width, depth, and/or radius of each of the grooved concentric circles  1300  in the light guide  140  may be selected to cooperate to redirect reflected light at angles required for the input light to enter and propagate through the propagation region  244  and, ultimately, to pass through multiple points on the projection surface  252  of the light guide  140  at a uniform illuminance (see  FIG. 16 ). Each deformation  1300  may operate to scatter light in more than one direction, and such that the scattered light may be emitted through the projection surface  252  of the light guide  140 . 
     In accordance with various embodiments of the invention, the shape, width, depth, and/or radius of each of the deformations  1300  may be selected to provide illumination that is substantially uniform in intensity across the projection surface  252  of the light guide  140 . The deformations  1300  may be arranged in the form of a plurality of concentric shapes about the center of the light guide  140 . For example, and without limitation, the shapes may be round, ellipsoidal, polygonal, or combinations thereof. Also for example, and without limitation, the density of deformations  1300  may increase from the edge of light guide  110  to the center of the light guide  140 . Varying the density of deformations  1300  in this manner may cause an optical mean free path within the light guide  140  to decrease as a function of distance from the edge of the light guide  140  to the center of the light guide  140 . The diminishing optical mean free path may facilitate an increasing ratio between the emitted portion and propagated portions of the light. The density, width, and/or depth of the deformations  1300  may increase in discrete steps, resulting in concentric areas containing different densities of deformations  1300 . 
     A skilled artisan will note that one or more of the aspects of the present invention may be performed on a computing device. The skilled artisan will also note that a computing device may be understood to be any device having a processor, memory unit, input, and output. This may include, but is not intended to be limited to, cellular phones, smart phones, tablet computers, laptop computers, desktop computers, personal digital assistants, etc.  FIG. 17  illustrates a model computing device in the form of a computer  610 , which is capable of performing one or more computer-implemented steps in practicing the method aspects of the present invention. Components of the computer  610  may include, but are not limited to, a processing unit  620 , a system memory  630 , and a system bus  621  that couples various system components including the system memory to the processing unit  620 . The system bus  621  may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI). 
     The computer  610  may also include a cryptographic unit  625 . Briefly, the cryptographic unit  625  has a calculation function that may be used to verify digital signatures, calculate hashes, digitally sign hash values, and encrypt or decrypt data. The cryptographic unit  625  may also have a protected memory for storing keys and other secret data. In other embodiments, the functions of the cryptographic unit may be instantiated in software and run via the operating system. 
     A computer  610  typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by a computer  610  and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer readable media may include computer storage media and communication media. Computer storage media includes volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, FLASH memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computer  610 . Communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, radio frequency, infrared and other wireless media. Combinations of any of the above should also be included within the scope of computer readable media. 
     The system memory  630  includes computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM)  631  and random access memory (RAM)  632 . A basic input/output system  633  (BIOS), containing the basic routines that help to transfer information between elements within computer  610 , such as during start-up, is typically stored in ROM  631 . RAM  632  typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit  620 . By way of example, and not limitation,  FIG. 17  illustrates an operating system (OS)  634 , application programs  635 , other program modules  636 , and program data  637 . 
     The computer  610  may also include other removable/non-removable, volatile/nonvolatile computer storage media. By way of example only,  FIG. 17  illustrates a hard disk drive  641  that reads from or writes to non-removable, nonvolatile magnetic media, a magnetic disk drive  651  that reads from or writes to a removable, nonvolatile magnetic disk  652 , and an optical disk drive  655  that reads from or writes to a removable, nonvolatile optical disk  656  such as a CD ROM or other optical media. Other removable/non-removable, volatile/nonvolatile computer storage media that can be used in the exemplary operating environment include, but are not limited to, magnetic tape cassettes, flash memory cards, digital versatile disks, digital video tape, solid state RAM, solid state ROM, and the like. The hard disk drive  641  is typically connected to the system bus  621  through a non-removable memory interface such as interface  640 , and magnetic disk drive  651  and optical disk drive  655  are typically connected to the system bus  621  by a removable memory interface, such as interface  650 . 
     The drives, and their associated computer storage media discussed above and illustrated in  FIG. 17 , provide storage of computer readable instructions, data structures, program modules and other data for the computer  610 . In  FIG. 17 , for example, hard disk drive  641  is illustrated as storing an OS  644 , application programs  645 , other program modules  646 , and program data  647 . Note that these components can either be the same as or different from OS  633 , application programs  633 , other program modules  636 , and program data  637 . The OS  644 , application programs  645 , other program modules  646 , and program data  647  are given different numbers here to illustrate that, at a minimum, they may be different copies. A user may enter commands and information into the computer  610  through input devices such as a keyboard  662  and cursor control device  661 , commonly referred to as a mouse, trackball or touch pad. Other input devices (not shown) may include a microphone, joystick, game pad, satellite dish, scanner, or the like. These and other input devices are often connected to the processing unit  620  through a user input interface  680  that is coupled to the system bus, but may be connected by other interface and bus structures, such as a parallel port, game port or a universal serial bus (USB). A monitor  691  or other type of display device is also connected to the system bus  621  via an interface, such as a graphics controller  690 . In addition to the monitor, computers may also include other peripheral output devices such as speakers  697  and printer  696 , which may be connected through an output peripheral interface  695 . 
     The computer  610  may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer  680 . The remote computer  680  may be a personal computer, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to the computer  610 , although only a memory storage device  681  has been illustrated in  FIG. 17 . The logical connections depicted in  FIG. 17  include a local area network (LAN)  671  and a wide area network (WAN)  673 , but may also include other networks  140 . Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets and the Internet. 
     When used in a LAN networking environment, the computer  610  is connected to the LAN  671  through a network interface or adapter  670 . When used in a WAN networking environment, the computer  610  typically includes a modem  672  or other means for establishing communications over the WAN  673 , such as the Internet. The modem  672 , which may be internal or external, may be connected to the system bus  621  via the user input interface  660 , or other appropriate mechanism. In a networked environment, program modules depicted relative to the computer  610 , or portions thereof, may be stored in the remote memory storage device. By way of example, and not limitation,  FIG. 17  illustrates remote application programs  685  as residing on memory device  681 . 
     The communications connections  670  and  672  allow the device to communicate with other devices. The communications connections  670  and  672  are an example of communication media. The communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. A “modulated data signal” may be a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. Computer readable media may include both storage media and communication media. 
     Some of the illustrative aspects of the present invention may be advantageous in solving the problems herein described and other problems not discussed which are discoverable by a skilled artisan. While the above description contains much specificity, these should not be construed as limitations on the scope of any embodiment, but as exemplifications of the presented embodiments thereof. Many other ramifications and variations are possible within the teachings of the various embodiments. While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best or only mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. 
     Thus, the scope of the invention should be determined by the appended claims and their legal equivalents, and not by the examples given.