Patent Publication Number: US-9890943-B2

Title: Thermally dissipated lighting system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Non-Provisional patent application Ser. No. 14/724,339 filed May 28, 2015 in the name of Caleb Timothy Badley and titled “Thermally Dissipated Lighting System,” which in turn claims priority to U.S. Provisional Patent Application No. 62/006,479 filed Jun. 2, 2014 in the name of Caleb Timothy Badley and titled “Thermally Dissipated Lighting System”. The entire contents of the foregoing applications are hereby incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     Embodiments of the technology relate generally to lighting systems, and more particularly to a lighting system that comprises a light emitting diode (LED) and a light emitting diode driver and that is configured to divert light-emitting-diode-generated heat away from the driver. 
     BACKGROUND 
     Light emitting diodes (LEDs) offer substantial potential benefit for illumination applications associated with energy efficiency, light quality, and compact size. However, light emitting diodes and the associated drivers that supply electricity to the light emitting diodes can be more sensitive to heat than their incandescent counterparts. 
     Accordingly, there are needs in the art for technology to manage heat associated with operating light emitting diodes for illumination applications. Need further exits for separately managing the heat generated by operating a light emitting diode and the heat generated by operating a driver that is associated with the light emitting diode. Need further exists for dissipating heat in outdoor lighting systems in which a light emitting diode and an associated driver are housed in one or more environmentally sealed housings. A capability addressing one or more such needs, or some other related deficiency in the art, would support improved illumination systems and more widespread utilization of light emitting diodes in lighting applications. 
     SUMMARY 
     A lighting system or luminaire can comprise two environmentally sealed housings for housing at least one light emitting diode and at least one light emitting diode driver. The exterior of one of the housings can be shaped to form a cavity. The exterior of the other housing can be shaped to extend partially into the cavity, for example in a nested arrangement. When the two housing are so arranged, an air gap between the two housings can remain open in the cavity. The air gap can promote heat dissipation. 
     The foregoing discussion is for illustrative purposes only. Various aspects of the present technology may be more clearly understood and appreciated from a review of the following text and by reference to the associated drawings and the claims that follow. Other aspects, systems, methods, features, advantages, and objects of the present technology will become apparent to one with skill in the art upon examination of the following drawings and text. It is intended that all such aspects, systems, methods, features, advantages, and objects are to be included within this description and covered by this application and by the appended claims of the application. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an isometric view of a lighting system, from a front perspective, according to some example embodiments of the disclosure. 
         FIG. 2  illustrates an isometric view of the lighting system, from a rear perspective, according to some example embodiments of the disclosure. 
         FIG. 3  illustrates an isometric view of the lighting system, from a top perspective, according to some example embodiments of the disclosure. 
         FIG. 4  illustrates an isometric view of the lighting system, from a side perspective, according to some example embodiments of the disclosure. 
         FIG. 5  illustrates the light-emitting side of the lighting system according to some example embodiments of the disclosure. 
         FIGS. 6A and 6B  (collectively  FIG. 6 ) illustrate the top of the lighting system according to some example embodiments of the disclosure. 
         FIGS. 7A and 7B  (collectively  FIG. 7 ) illustrate an exploded view of the lighting system, without mounting hardware, according to some example embodiments of the disclosure. 
         FIGS. 8A and 8B  (collectively  FIG. 8 ) illustrate cross sectional views of the lighting system according to some example embodiments of the disclosure. 
         FIGS. 9A and 9B  (collectively  FIG. 9 ) illustrate an exploded cross sectional view of the lighting system, without mounting hardware, according to some example embodiments of the disclosure. 
     
    
    
     The drawings illustrate only example embodiments and are therefore not to be considered limiting of the embodiments described, as other equally effective embodiments are within the scope and spirit of this disclosure. The elements and features shown in the drawings are not necessarily drawn to scale, emphasis instead being placed upon clearly illustrating principles of the embodiments. Additionally, certain dimensions or positionings may be exaggerated to help visually convey certain principles. In the drawings, similar reference numerals among different figures designate like or corresponding, but not necessarily identical, elements. 
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     A representative lighting system can comprise two housings. An outer surface of one of the housings can be shaped to form a cavity. A portion of the other housing can extend partially into the cavity, for example in a nested arrangement with a gap at the bottom of the cavity. Heat generated during operation of the lighting system can dissipate via the gap. 
     Some representative embodiments will be described below with example reference to the accompanying drawings that illustrate a representative embodiment of the technology. The technology 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 technology to those appropriately skilled in the art. 
     The figures illustrate an example embodiment of a lighting system  100  that comprises light emitting diodes  120  and a light emitting diode driver  175  that each generates heat during operation. The illustrated lighting system  100  further comprises technology to divert the light-emitting-diode-generated heat away from the light emitting diode driver  175 , thereby extending the life of the light emitting diode driver  175 . As illustrated and discussed below, the light emitting diodes  120  are enclosed in a light source housing  150 , and the light emitting diode driver  175  is enclosed in a driver housing  125  with an access door  130 . In preparation for describing the lighting system  100  in further detail, the figures will now be discussed individually. 
       FIG. 1  illustrates an isometric view of the lighting system  100 , from a front perspective.  FIG. 2  illustrates an isometric view of the lighting system  100 , from a rear perspective.  FIG. 3  illustrates an isometric view of the lighting system  100 , from a top perspective.  FIG. 4  illustrates an isometric view of the lighting system  100 , from a side perspective.  FIG. 5  illustrates the front or light-emitting side of the lighting system  100 . 
       FIGS. 6A and 6B  illustrate the top of the lighting system  100 . In the view of  FIG. 6A , mounting hardware  105 / 110  of the lighting system  100  is attached. In  FIG. 6B , the mounting hardware  105 / 110  is removed. Thus,  FIGS. 6A and 6B  illustrate common views, except that the mounting hardware  105 / 110  is present in  FIG. 6A  and removed in  FIG. 6B . 
       FIG. 7  (composed of  FIGS. 7A and 7B ) illustrates an exploded view of the lighting system  100 , without the mounting hardware  105 / 110 . In this exploded view, the driver housing  125  of the lighting system  100  is separated from the light source housing  150  of the lighting system  100 . 
       FIGS. 8A and 8B  illustrate cross sectional views of the lighting system  100 . In the cross sectional view of  FIG. 8A , mounting hardware  105 / 110  of the lighting system  100  is attached. In the cross sectional view of  FIG. 8B , the mounting hardware  105 / 110  is removed. Thus,  FIGS. 8A and 8B  illustrate common views, except that the mounting hardware  105 / 110  is present in  FIG. 8A  and removed in  FIG. 8B . 
       FIG. 9  (composed of  FIGS. 9A and 9B ) illustrates an exploded cross sectional view of the lighting system  100 , without the mounting hardware  105 / 110 . In the exploded view, the driver housing  125  of the lighting system  100  is separated from the light source housing  150  of the lighting system. 
     Referring now to all the figures, the lighting system  100  will be described in further detail. 
     In the illustrated example embodiment, the lighting system  100  comprises mounting hardware  105 / 110 . The illustrated mounting hardware  105 / 110  is configured for mounting the lighting system  100  on an end of a pole. In mounting, the pole end inserts into the mounting sleeve  105 , and three circumferentially disposed fasteners (see  FIG. 5 ) screw down on the pole. In addition to the mounting sleeve  105 , the mounting hardware  105 / 110  comprises a coupler  110  that is attached to the driver housing  125 . 
     As can be seen in  FIG. 4 , the coupler  110  and the mounting sleeve  105  provide rotational adjustment to set angle of illumination relative to the pole. An installer or service technician can set the coupler  110  to direct light downward, horizontally, upward, or at various angles depending on application and preference. For example, a user may want a horizontal angle to spread light across a parking lot or large field. Meanwhile another user may want illumination to be concentrated downward, towards a particular work area. 
     In a typical installation, electrical supply lines (not illustrated) extend through the pole, the mounting sleeve  105 , the coupler  110 , and an aperture  184  in the driver housing  125 . So extended, the electrical supply lines can provide electrical line power to the light emitting diode driver  175  and, in turn, to the light emitting diodes  120 . 
     As visible in  FIG. 8 , the light emitting diode driver  175  is mounted within the driver housing  125 , specifically to an interior surface of the access door  130 . The opposite, exterior surface of the access door  130  has heat sink fins  160  that dissipate heat. Thus, the rear exterior of the lighting system  100  comprises heat sink fins  160  for dissipating heat generated by the light emitting diode driver  175  in connection with driving the light emitting diodes  120 . 
     A gasket  176  is located between the driver housing  125  and the access door  130 . The gasket  176  helps insulate the access door  130  from heat flowing from the light emitting diodes  120 . In an example embodiment, the gasket  176  separates the metal surface of the driver housing  125  from the metal surface of the light source housing  150 . Accordingly, the gasket  176  can serve as a heat insulator or isolator in an example embodiment. 
     In operation, the light emitting diode driver  175  takes the line power and converts it to electricity of suitable form for driving the light source, which in this example comprises two chip-on-board (COB) light emitting diodes  120 . One or more arrays of discrete light emitting diodes can be utilized in some embodiments as an alternative to chip-on-board light emitting diodes. The converted electricity flows through wires (not illustrated) that extend between the driver housing  125  and the light source housing  150 . The wires extend out of the driver housing  125  via an aperture  181 . The wires further extend into the light source housing  150  via a corresponding aperture  182 . One or more gaskets  180  environmentally seal the two apertures  181 ,  182 . See  FIGS. 8 and 9  for an example embodiment. 
     Each light emitting diode  120  is mounted at the rear of a light cavity  106  formed by a concave reflective surface  108 . As illustrated, each light emitting diode  120  has an associated mount  136  that provides mechanical attachment and electrical connection. Other embodiments can utilize other mounting technologies, for example screws, adhesives, etc. 
     A window  101  extends over the light emitting face of the light source housing  150  and provides environmental protection as well as light transmission. In some embodiments, the window  101  comprises a sheet of glass or silica. The window  101  has an opaque area  131  with two transparent areas  132  located in front of the light emitting diodes  120 . The opaque area  131  can comprise a film created by screen-printing in black or another appropriate color in some embodiments, for example. In some embodiments, the area  131  is partially opaque or may be translucent, for example via frosting the window  101 . 
     In the illustrated example embodiment, the light source housing  150  comprises two arrays of heat sink fins  155  opposite from the window  101 . The heat sink fins  155  dissipate heat generated by the light emitting diodes  120  during operation. To shield the light emitting diode driver  175  from the heat, the heat sink fins  155  extend or project into a large air gap  195  located between the light source housing  150  and the driver housing  125 . 
     In the illustrated embodiment, contact between the light source housing  150  and the driver housing  125  is limited to a peripheral area  161  (and may be further limited or substantially precluded by the gasket  176 ). The housings  125 ,  150  are typically cast metal, for example aluminum, but may be made of other materials having suitable mechanical and thermal properties. As illustrated in  FIGS. 8 and 9 , the driver housing  125  protrudes into a cavity of the light source housing  150 , with an air gap  107  that extends along the sides of the cavity and separates the driver housing  125  from the light source housing  150 . The air gap  107  can be viewed as an extension of the air gap  195  or vice versa. In an example embodiment, the driver housing  125  and the light source housing  150  can be viewed as nested together. 
     In operation, the light emitting diodes  120  produce heat. As best viewed in  FIG. 8B , a portion of the light-emitting-diode-generated heat dissipates through the heat sink fins  155  disposed in the air gap  195  located between the light source housing  150  and the driver housing  125 . Another portion of the light-emitting-diode-generated heat flows along the walls of the light source housing  150 , along the air gap  107 . That heat flows to the walls of the driver housing  125  via a thermal connection at the peripheral area  161  where the two housing  125 ,  150  are in physical contact. That heat then flows around the exterior corner of the access door  130  and dissipates through the heat sink fins  160 . The gasket  176  helps insulate the driver  175  from that heat. 
     Thus, in the illustrated example embodiment, the light source housing  150  has an exterior surface that is shaped to form a cavity. Meanwhile, the driver housing  125  has an exterior surface that is shaped to extend partially into the cavity when the driver housing  125  and the light source housing  150  are aligned and positioned against one another. When the driver housing  125  and the light source housing  150  are arranged in this configuration, an air gap  107 / 195  between the two housings can remain open, including at the bottom of the cavity. The air gap  195  and/or the air gap  107  can promote heat dissipation. For example, the air gaps  107 / 195  can help route light-emitting-diode-generated heat away from the driver  175 . As another example, the air gaps  107 / 195  can thermally insulate the driver housing  125  from the light source housing  150 . As another example, the air gap  195  can provide airflow for cooling the heat sink fins  155  that extend into the air gap  195 . As best shown in  FIG. 6B , the air gap  195  can provide an opening that extends from the upper side of the lighting system  100  to the lower side of the lighting system  100 . The heat sink fins  155  can heat the air in the air gap  195 , with the heated air rising in the opening, exiting the opening, and drawing cool air into the opening from below. Thus, the air gap  195  can create a chimney effect for heat dissipation and thermal management. 
     Many modifications and other embodiments of the disclosures set forth herein will come to mind to one skilled in the art to which these disclosures pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosures are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of this application. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.