Patent Publication Number: US-10317066-B2

Title: Recesssed downlight fixture with heatsink

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application No. 62/327,423, filed Apr. 25, 2016, which is incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     1. Field of Invention 
     The present invention relates generally to light assemblies, and more specifically, but not by way of limitation, to recessed downlights. 
     2. Description of Related Art 
     In modern building designs, there is tremendous pressure to reduce floor-to-floor height in order to reduce construction costs. A few centimeters saved per floor can add up to large savings in the cost of the building, including its core components and cladding. One area where floor-to-floor height can be reduced is in the plenum space, which is the above-ceiling space in buildings where lighting fixtures, ductwork, sprinkler piping, wiring, and/or the like can be disposed. 
     Downlights are designed to be recessed into a ceiling and typically are installed such that they extend into the plenum space. Thus, reducing the height of a downlight can allow for corresponding reductions in floor-to-floor height. Existing downlights include heatsinks designed to dissipate heat from their light sources. Such heatsinks may have increased importance for light-emitting diode (LED) light sources; for example, failure to sufficiently dissipate heat from an LED light source can damage LED phosphor, resulting in lower light output, changes in color, and/or decreases in life expectancy, particularly if the LED light source is receiving 350 or more milliamps (mA). For at least these reasons, a typical downlight includes a relatively large, bulky, and finned heat sink, which adds centimeters to the overall height of the downlight. 
     SUMMARY 
     Some embodiments of the present disclosure are downlights that comprise a housing with at least one wall that serves as a heatsink. To illustrate, a light fixture can be disposed within the housing such that the light fixture is adjacent to and in thermal communication with the wall. In at least this way, the wall of the housing can eliminate the need for a traditional heatsink, thereby reducing the height of the downlight. 
     Some embodiments of the present downlights comprise: a housing including a thermally-conductive upper wall, a lower wall that defines an aperture, and a sidewall extending between the thermally-conductive upper wall and the lower wall, and a light fixture comprising or configured to receive a light source, where the light fixture is configured to be coupled to the housing such that the light source (when coupled to the light fixture) is adjacent to and in thermal communication with the thermally-conductive upper wall. 
     In some downlights, the light fixture is configured to be coupled to the housing such that the light source is within 20, 15, 10, or 5 millimeters (mm) of the thermally-conductive upper wall. In some downlights, the light fixture is configured to be coupled to the housing such that no portion of the light fixture extends vertically beyond the thermally-conductive upper wall. Some downlights comprise a thermally-conductive mounting plate configured to be coupled between the light fixture and the thermally-conductive upper wall. 
     In some downlights, the thermally-conductive upper wall is removably coupled to the sidewall. In some downlights, the thermally-conductive upper wall has a first maximum thickness, and the sidewall has a second maximum thickness that is smaller than the first maximum thickness. In some downlights, the first maximum thickness is at least 125, 150, 175, 200, 225, 250, 275, 300, 325, or 350% of the second maximum thickness. In some downlights, the upper wall has a maximum thickness of at least 0.2 centimeters (cm) and less than 0.6 cm. 
     In some downlights, a majority, by weight, of the thermally-conductive upper wall comprises a first material, and a majority, by weight, of the sidewall comprises a second material that is different than the first material. In some downlights, the upper wall comprises aluminum, copper, silver, gold, and/or a thermally-conductive polymer. 
     In some downlights, a maximum vertical distance between the lower wall and the thermally-conductive upper wall is less than 100, 95, 90, 85, 80, 75, 70, 65, 60, 55 or 50 mm. In some downlights, a maximum transverse dimension of the thermally-conductive upper wall is at least 4, 5, 6, 7, 8, 9, or 10 times a maximum transverse dimension of the light source. In some downlights, a maximum transverse dimension of the housing is at least 1.25, 1.50, 1.75, 2.00, 2.25, 2.50, or 2.75 times a maximum transverse dimension of the aperture. In some downlights, opposing portions of the sidewall are parallel to one another. In some downlights, the sidewall defines one or more openings. 
     In some downlights, the light source has a maximum rated current of at least 500 mA. In some downlights, the light fixture comprises a reflector configured to direct light from the light source and through the aperture. In some downlights, the light fixture is configured to be coupled to the housing such that the reflector is spaced apart from the sidewall. 
     Some downlights comprise a baffle having an upper end and a lower end, the baffle defining an interior channel extending between the upper end and the lower end, where the baffle is configured to be coupled to the housing such that the upper end of the baffle extends through the aperture. In some downlights, the baffle is configured to be coupled to the housing such that the upper end of the baffle is spaced apart from the reflector. Some downlights comprise a lens or a diffuser configured to be coupled to the upper end of the baffle. 
     Other embodiments include methods of installing a downlight or replacing a light source or a light fixture of the downlight. 
     The term “coupled” is defined as connected, although not necessarily directly, and not necessarily mechanically; two items that are “coupled” may be unitary with each other. The term “substantially” is defined as largely but not necessarily wholly what is specified (and includes what is specified; e.g., substantially 90 degrees includes 90 degrees and substantially parallel includes parallel), as understood by a person of ordinary skill in the art. In any disclosed embodiment, the term “substantially” may be substituted with “within [a percentage] of” what is specified, where the percentage includes 0.1, 1, 5, and 10 percent. The terms “a” and “an” are defined as one or more unless this disclosure explicitly requires otherwise. Further, a device or system that is configured in a certain way is configured in at least that way, but it can also be configured in other ways than those specifically described. 
     The terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), and “include” (and any form of include, such as “includes” and “including”) are open-ended linking verbs. As a result, an apparatus that “comprises,” “has,” or “includes” one or more elements possesses those one or more elements, but is not limited to possessing only those one or more elements. Likewise, a method that “comprises,” “has,” or “includes” one or more steps possesses those one or more steps, but is not limited to possessing only those one or more steps. 
     Any embodiment of any of the apparatuses, systems, and methods can consist of or consist essentially of—rather than comprise/have/include—any of the described steps, elements, and/or features. Thus, in any of the claims, the term “consisting of” or “consisting essentially of” can be substituted for any of the open-ended linking verbs recited above in order to change the scope of a given claim from what it would otherwise be using the open-ended linking verb. 
     The feature or features of one embodiment may be applied to other embodiments, even though not described or illustrated, unless expressly prohibited by this disclosure or the nature of the embodiments. 
     Some details associated with the embodiments described above and others are described below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following drawings illustrate by way of example and not limitation. For the sake of brevity and clarity, every feature of a given structure is not always labeled in every figure in which that structure appears. Identical reference numbers do not necessarily indicate an identical structure. Rather, the same reference number may be used to indicate a similar feature or a feature with similar functionality, as may non-identical reference numbers. The figures are drawn to scale (unless otherwise noted), meaning the sizes of the depicted elements are accurate relative to each other for at least the embodiment depicted in the figures. 
         FIG. 1  is a perspective view of an embodiment of the present downlights. 
         FIG. 2  is a perspective view of the downlight of  FIG. 1  with a transparent upper wall to permit viewing of interior components. 
         FIG. 3  is a cross-sectional side view of the downlight of  FIG. 1 , taken along line A of  FIG. 1 . 
         FIG. 4  is a top view of the downlight of  FIG. 1 . 
         FIG. 5  is a side view of the downlight of  FIG. 1 . 
         FIG. 6  depicts the downlight of  FIG. 1  recessed into a ceiling. 
         FIG. 7  is a perspective view of a mounting plate and a light source holder of the downlight of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-6  show an embodiment  100  of a downlight. Downlight  100  is a type of light assembly that is configured to be recessed into a structure  5 , such as, for example, a ceiling, wall, floor, or the like. Downlight  100  can comprise a housing  10  and a light fixture  30  that is disposable within the housing and comprises, or is configured to receive, a light source  32 . For example, housing  10  comprises walls (e.g., an upper wall  12 , a lower wall  14 , and a sidewall  18  that extends between the upper and lower walls) that define an interior volume  20  within which light fixture  30  can be disposed. As described below, at least one of the walls (e.g., upper wall  12 ) is configured to be in thermal communication with light source  32  such that the wall functions as a heat sink for the light source. Such a wall can be thermally-conductive. Such a wall can be flat (e.g., planar, finless), which can reduce a space occupied by housing  10 . As used herein, two components are in “thermal communication” when they are coupled to one another such that heat can be conducted between the two components. Such a coupling can be via one or more thermally-conductive components that are disposed between the two components (e.g., mounting plate  28 , described below) or one in which the two components are in contact with one another. 
     In the embodiment shown, upper wall  12  is removably coupled to sidewall  18  (e.g., via one or more fasteners), which can facilitate installation and removal of components within interior volume  20 . Lower wall  14  can define an aperture  16  ( FIGS. 3 and 6 ). More particularly, aperture  16  can be defined by a downwardly-extending flange  17  of the lower wall. Aperture  16  can be located on lower wall  14  directly below the portion of upper wall  12  to which light fixture  30  is mountable such that light emitted from the light fixture is directed through the aperture. In this embodiment, at least a portion of upper wall  12  and at least a portion of lower wall  14  can be parallel to one another. Similarly, opposing portions of sidewall  18  (e.g., on front and back sides of the sidewall and/or on left and right sides of the sidewall) can be parallel to one another. 
     Downlight  100  can include one or more brackets  22  coupled to housing  10  for securing the housing relative to structure  5 . As shown, each of the one or more brackets can be coupled to sidewall  18 . One or more brackets  22  can each be coupled to a hangar bar  21 , which may be length-adjustable, that is configured to be coupled to a support structure. 
     Housing  10  can define one or more openings, such as openings  24  and  25 , that provide access to interior volume  20  from an exterior of the housing. To illustrate, sidewall  18  can define an opening  24  that is sized and shaped to permit wiring to extend through the opening, such as wiring for supplying power to light fixture  30 . To further illustrate, sidewall  18  can define one or more openings  25  (e.g., two openings  25  on its front side  27  and two openings  25  on its rear side  29 ) for permitting airflow through the housing. 
     Housing  10  can be low-profile. For example, a maximum vertical distance (measured along the Y-axis,  FIG. 1 ) between lower wall  14  and upper wall  12  can be less than or equal to any one of, or between any two of: 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, or 50 mm (e.g., less than 60, 55, or 50 mm). In at least this way, a space above structure  5  required for installing downlight  100  can be reduced. As described below, such functionality can be facilitated by at least one wall (e.g., upper wall  18 ) of housing  10  serving as a heat sink for light source  32 , eliminating the need for a traditional, space consuming heat sink to be disposed within or coupled to the housing. 
     In this embodiment, upper wall  12  is configured to serve as a heat sink for light source  32 . Upper wall  12  can have a different thickness than that of other housing walls, such as lower wall  14  and/or sidewall  18 . For example, upper wall  12  can have a maximum thickness that is greater than a maximum thickness of sidewall  18 . More particularly, the maximum thickness of upper wall  12  can be greater than or equal to any one of, or between any two of: 125, 150, 175, 200, 225, 250, 275, 300, 325, or 350% (e.g., at least 125%) of the maximum thickness of sidewall  18 . The maximum thickness of upper wall  12  can be between 2.5 mm and 10.0 mm. The thickness of upper wall  12  can be substantially constant (e.g., not varying by more than 10%). Upper wall  12  can be flat (e.g., planar, finless). For example, upper wall  12  has a lower surface  13  (facing interior volume  20  when the upper wall is coupled to sidewall  18 ) and an upper surface  15  opposite the lower surface, each of which can be flat. 
     Upper wall  12  can comprise a thermally-conductive material, such as, for example, aluminum, copper, silver, gold, a thermally-conductive polymer, and/or the like. A thermally-conductive material can have a thermal conductivity that is greater than or equal to any one of, or between any two of: 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, or 400 W·m −1 ·K −1  (e.g., at least 200 W·m −1 ·K −1 ). Upper wall  12  can comprise a different material than that of other housing walls, such as lower wall  14  and/or sidewall  18 . For example, a majority, by weight, of upper wall  12  can comprise a first material, and a majority, by weight, of sidewall  18  can comprise a second material that is different than the first material. In embodiments where other wall(s) of a housing (e.g.,  10 ) (e.g., a lower wall  14  and/or sidewalls  18 ) are configured to serve as a heat sink for a light source (e.g.,  32 ), the other wall(s) can include one or more of the features described above for upper wall  12 . 
     Upper wall  12  can be dimensioned (e.g., in length and width) to facilitate the upper wall in conducting heat away from light source  32 . For example, a maximum transverse dimension (measured along axis X or axis Z,  FIG. 1 ) of upper wall  12  can be greater than or equal to any one of, or between any two of: 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, or 40 times (e.g., at least 4 times) a maximum transverse dimension (measured along axis X or axis Z) of light source  32 . To illustrate, if light source  32  is an LED light source, the maximum transverse dimension of the light source may be the maximum transverse dimension of a circuit board to which LED(s) of the light source are mounted. For further example, upper wall  12  (e.g., lower surface  13  and/or upper surface  15  thereof) can have a surface area that is greater than any one of, or between any two of: 50, 55, 60, 65, 70, or 75 cm 2  per watt of light source  32 . 
     A maximum transverse dimension (measured along axis X or axis Z) of housing  10  can be greater than or equal to any one of, or between any two of: 1.25, 1.50, 1.75, 2.00, 2.25, 2.50, or 2.75 times (e.g., at least 1.25 times) a maximum transverse dimension (measured along axis X or axis Z) of aperture  16 . Upper wall  12  can have dimensions (e.g., length and/or width) that are substantially equal to corresponding dimensions of housing  10 . For example, when upper wall  12  is coupled to sidewall  18 , the upper wall can overlie substantially all of an upper edge  19  of the sidewall. 
     Light fixture  30  can comprise, or be configured to receive, a light source  32 . When light source  32  is coupled to light fixture  30  and the light fixture is disposed within housing  10 , light emitted from the light source can be directed toward lower wall  14  and through aperture  16 . Light source  32  can be any suitable light source, whether electroluminescent (e.g., light-emitting diode(s)), fluorescent (e.g., fluorescent tube(s)), incandescent (e.g., incandescent light bulbs(s)), and/or the like. For example, in this embodiment, light source  32  is an LED light source. 
     In this embodiment, light fixture  30  is configured to be coupled to housing  10  such that light source  32  is in thermal communication with upper wall  12 , thereby allowing the upper wall to function as a heat sink for the light source. For example, when light fixture  30  is coupled to housing  10 , light source  32  can be adjacent to upper wall  12 , meaning the light source is within 20, 15, 10, 5, 3, or 2 mm of the upper wall or is in contact with the upper wall. As used herein, “adjacent” neither requires nor excludes direct contact. Light fixture  30  can be coupled to housing  10  in any suitable fashion that does not undesirably impair heat transfer between light source  32  and the housing. For example, downlight  100  can include a thermally-conductive mounting plate  28  configured to be disposed between light fixture  30  and upper wall  12  and to couple the light fixture to the upper wall. Light fixture  30  can be coupled to housing  10  such that no portion of the light fixture extends beyond upper wall  12 . In at least this way, a space above structure  5  required for installing downlight  100  can be reduced Aperture  16  and light fixture  30  and/or light source  32  can be sized to permit passage of the light fixture and/or light source through the aperture, which can facilitate installation and removal of the light fixture and/or light source into and from housing  10  once the housing is installed within structure  5 . 
     Light fixture  30  can include a reflector  38  configured to direct light from light source  32  through a light-transmitting cover  36  (if present, described below) and aperture  16 . When light fixture  30  is coupled to housing  10 , reflector  38  can be spaced apart from sidewall  18 , lower wall  14 , and/or light-transmitting cover  36 . 
     Downlight  100  can include a driver  62  configured to supply power to light source  32 . For example, driver  62  can be configured to receive alternating current power, convert the alternating current power to direct current power, and supply the direct current power to light source  32  at effective voltages and currents for operating the light source. A light source (e.g.,  32 ), such as an LED light source, can have a maximum rated current that is greater than or equal to any one of, or between any two of: 300, 350, 400, 450, 500, 550, 600, 650, 700, or 750 mA (e.g., at least 300 mA, at least 500 mA). Downlight  100  can include one or more (e.g., flexible) conduits for routing wires or cables to and/or from light source  32 , driver  62 , and/or other components. 
     Downlight  100  can comprise a baffle  42  defining an interior channel  46  that extends between an upper end  43  and a lower end  44  of the baffle. Baffle  42  can be coupled to housing  10  such that upper end  43  extends through aperture  16 . In this embodiment, when baffle  42  is coupled to housing  10 , upper end  43  is spaced apart from reflector  38 . Coupling of baffle  42  to housing  10  can be accomplished in any suitable fashion, such as, for example, via one or more fasteners, one or more tabs (e.g.,  50 ), interlocking features of the baffle and the housing, a friction fit between the baffle and the housing, and/or the like, and such a coupling can permit decoupling of the baffle from the housing. In this embodiment, an interior cross-section of baffle  42  is square; however, in other embodiments, a baffle (e.g.,  42 ) can define an interior cross-section that is circular, elliptical, otherwise rounded, triangular, and/or otherwise polygonal. 
     Downlight  100  can include a light-transmitting cover  36  through which light emitted from light source  32  can be conveyed. To illustrate, cover  36 , which can be a lens, diffuser, or the like, can comprise glass, plastic, or any other suitable transparent or translucent material. In this embodiment, cover  36  is coupled to baffle  42  such that light that travels from upper end  43  to lower end  44  within interior channel  46  passes through the cover. For example, cover  36  can extend completely across interior channel  46 . In other embodiments, such a cover (e.g.,  36 ) can be coupled to a reflector (e.g.,  38 ), an aperture (e.g.,  16 ), or the like. Coupling of cover to baffle  42  (or to other components in other downlights) can be removable to, for example, facilitate access to interior volume  20  once downlight  100  is installed. In this embodiment, cover  36  is square; however, in other embodiments, a cover (e.g.,  36 ) can be circular, elliptical, otherwise rounded, triangular, and/or otherwise polygonal. 
     To facilitate coupling of light fixture  30  to housing  10  and bringing light source  32  into thermal communication with the housing, downlight  100  can include a thermally-conductive mounting plate  28 . Plate  28 , and other components described as thermally-conductive, can comprise any of the thermally-conductive materials described above. In this embodiment, plate  28  is configured to be coupled to upper wall  12 . For example, plate  28  can define one or more openings  47  that correspond to openings in upper wall  12  such that one or more fasteners can be disposed within opening(s)  47  and the opening(s) in the upper wall to couple the plate to the upper wall. In other embodiments, coupling of a mounting plate (e.g.,  28 ) to a housing wall (e.g., an upper wall  12 ) can be accomplished in any suitable fashion, such as, for example, via welding, adhesive, interlocking features of the plate and the housing wall, and/or the like. Plate  28  can have an upper surface that corresponds to lower surface  13  of upper wall  12 ; for example, in this embodiment, the upper surface of the plate and the lower surface of the upper wall are both flat. 
     In this embodiment, plate  28  is configured to be coupled to light fixture  30 , and more particularly, to a light source holder  37  thereof ( FIG. 7 ). Provided by way of illustration, holder  37  can define a recess or opening  39  configured to receive light source  32  and can define one or more channels  45  configured to receive wires for supplying power to the light source. In this embodiment, reflector  38  can be coupled to holder  37 . For example, holder  37  can define one or more slots or openings  51  that are configured to receive corresponding projection(s) on an upper end of reflector  38  to couple the reflector to the holder. 
     In the embodiment shown, plate  28  can define one or more openings  49  ( FIG. 3 ) that correspond to one or more openings  48  defined by holder  37  such that one or more fasteners can be disposed within opening(s)  49  and opening(s)  48  to couple the plate to the holder. In other embodiments, coupling of a mounting plate (e.g.,  28 ) to a light source holder (e.g.,  37 ) can be accomplished in any suitable fashion, such as, for example, via welding, adhesive, interlocking features of the plate and the holder, and/or the like. When plate  28  is coupled to upper wall  12  and light fixture  30 , the plate is disposed between, and is thermal communication with, the upper wall and the light fixture. 
     Downlight  100  can comprise a trim ring  60 . In this embodiment, trim ring  60  can be removably coupled to lower end  44  of baffle  42 ; however, in embodiments without a baffle (e.g.,  42 ) a trim ring (e.g.,  60 ) can be coupled to a housing (e.g.,  10 ). Trim ring  60 , and more particularly, a flange  61  of the trim ring that extends outwardly therefrom, can be configured to conceal an area around aperture  16  to provide an aesthetically pleasing appearance. Such a trim ring  60  may be particularly useful when an opening formed in structure  5  for downlight  100  is larger than aperture  16 . 
     In the embodiment shown, light fixture  30  can be installed in housing  10  by coupling the light fixture to plate  28 . Light source  32 , if not installed with light fixture  30 , can be installed in housing  10  by coupling the light source to holder  37 . When light fixture  30 , including light source  32 , is coupled to plate  28  and the plate is coupled to upper wall  12 , the light source is in thermal communication with the upper wall. Downlight  100  can be mounted in a space behind structure  5  (e.g., a gap between a floor and a ceiling, a plenum space, a gap between walls, an attic, and/or the like) such that aperture  16  is aligned with an opening in the structure. Components of downlight  100 , such as light fixture  30 , light source  32 , plate  28 , baffle  42 , cover  36 , and/or the like, can be installed within housing  10  through aperture  16 . 
     The above specification and examples provide a complete description of the structure and use of illustrative embodiments. Although certain embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the scope of this invention. As such, the various illustrative embodiments of the methods and systems are not intended to be limited to the particular forms disclosed. Rather, they include all modifications and alternatives falling within the scope of the claims, and embodiments other than the one shown may include some or all of the features of the depicted embodiment. For example, elements may be omitted or combined as a unitary structure, and/or connections may be substituted. Further, where appropriate, aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples having comparable or different properties and/or functions, and addressing the same or different problems. Similarly, it will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. 
     The claims are not intended to include, and should not be interpreted to include, means-plus- or step-plus-function limitations, unless such a limitation is explicitly recited in a given claim using the phrase(s) “means for” or “step for,” respectively.