Patent Publication Number: US-7901109-B2

Title: Heat sink apparatus for solid state lights

Description:
BRIEF DESCRIPTION OF THE INVENTION 
     This invention relates generally to solid state lights. More specifically, this invention relates to heat sink apparatuses for solid state lights. 
     BACKGROUND OF THE INVENTION 
     The operational power of many current solid state lights, such as light-emitting diode (LED) lights, is often limited by the solid state lights&#39; ability to dissipate heat. More particularly, increasing the current of a solid state light increases the amount of heat generated. Beyond a certain point, this excess heat becomes detrimental to the performance of the solid state device, resulting in reduced performance and/or operational life. Accordingly, increasing the ability of a solid state light to dissipate heat allows for higher power, and thus brighter, more efficient solid state lights. Thus, ongoing efforts exist to increase the amount of heat dissipated from solid state lights. 
     SUMMARY OF THE INVENTION 
     The invention can be implemented in a number of ways, including as an apparatus, as a device incorporating both heat sink and solid state light source, and as an assembly. 
     In one embodiment, a heat sink apparatus for a solid state light comprises a heat sink comprising a first end configured for connection to a solid state light, a second end opposite the first end, and a heat dissipating portion between the first end and the second end. The heat dissipating portion has an elongated portion and a plurality of fins for dissipating heat generated by the solid state light, the fins extending from the elongated portion. 
     In another embodiment, a solid state light assembly comprises a solid state light and a heat sink affixed to the solid state light. The heat sink has a plurality of fins for dissipating heat generated by the solid state light. 
     Other aspects and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIGS. 1A-1B  are side and top views, respectively, of a heat sink apparatus for use with solid state lights in accordance with embodiments of the current invention. 
         FIG. 2  is a side view of an exemplary chandelier, illustrating use of the heat sink apparatus of  FIGS. 1A-1B . 
         FIGS. 3A-3C  are side, bottom, and top views, respectively, of a heat sink apparatus for use with solid state lights in accordance with further embodiments of the current invention. 
         FIGS. 4A-4B  are cutaway side views illustrating details of heat sink apparatuses of the current invention. 
     
    
    
     Like reference numerals refer to corresponding parts throughout the drawings. 
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
     As noted above, ongoing efforts exist to increase the heat dissipation of solid state lights. One embodiment of the current invention seeks to increase heat dissipation by affixing a separate heat sink to the solid state light, thus accomplishing increased heat dissipation via a separate, easily-attached device; a second embodiment integrates the solid state light source into the heat sink itself. In this manner, embodiments of the invention increase the amount of heat dissipated from solid state lights without requiring any redesign of the traditional light fixtures or lamps. This has the twin benefits of increasing heat dissipation, and thus allowing increased solid state light power, while also shifting the burden of heat dissipation to a separate or integrated device, so that solid state lights can be optimized for better lighting performance, rather than for increased heat dissipation. 
       FIGS. 1A-1B  are side and top views, respectively, of a heat sink assembly for use with solid state lights in accordance with embodiments of the current invention. The heat sink apparatus  10  includes a first end  20  with an attached solid state light  30 , a second end  40 , and an intermediate elongated portion  50 . A number of fins  60  extend from the elongated portion  50 . 
       FIGS. 1A-1B  illustrate an embodiment in which the heat sink apparatus  10  of the invention is arranged in a generally vertical configuration. In the operation of this embodiment, the fins  60  of the heat sink apparatus  10  provide added surface area available for convective heat transfer. That is, heat from the solid state light  30  is transferred to the fins  60 , heating the fins. Air warmed by heat from the fins  60  rises, generating air (or other suitable fluid) flow across the fins  60  in the vertical direction (i.e., from the second end  40  to the first end  20 ) and increasing the amount of heat dissipated from the solid state light  30 . Thus, the addition of heat sink apparatus  10  to solid state light  30  allows for more heat to be dissipated from solid state light  30 , in turn allowing for brighter and more efficient solid state lights  30 . One of ordinary skill in the art will realize that it is desirable for the fins  60  to be arranged so as to maximize the amount of surface area available for convective heat transfer. Accordingly, in the generally vertical configuration of  FIGS. 1A-1B , it is desirable for the fins  60  to extend generally radially from the elongated portion  50 , as shown. 
     The heat sink apparatus  10  can also include an optional sleeve  70  that can be affixed to (or otherwise extend from) the second end  40 , so as to protect the fins  60  from damage as well as to channel air (or another suitable fluid medium) across the fins  60 . In  FIGS. 1A-1B , the sleeve  70  is shown in solid lines on the left as separate from the heat sink apparatus  10 , and in dashed lines on the right as installed on the heat sink apparatus  10 . The sleeve  70  can include a bottom portion  75  with holes  80  to allow for air flow across the fins  60 . As above, the sleeve  70  is optional and the invention contemplates embodiments that both include and exclude such a sleeve  70 . Furthermore, the holes  80  need not be limited to circular holes, as shown. The invention includes any arrangement and configuration of holes  80 . Additionally, the bottom portion  75  can be open, with sleeve  70  attached to second end  40  by struts, flanges, or the like, rather than by a bottom portion  75 . 
     One of ordinary skill in the art will observe that the heat sink apparatus  10  can be configured for use with conventional solid state lights such as LED light bulbs, in many of the same contexts. As one example, the heat sink apparatus  10  can be employed with solid state lights and light fixtures used in typical home and business environments. One such light fixture is shown in  FIG. 2 , which is a side view of an exemplary chandelier employing the heat sink apparatus of  FIGS. 1A-1B . Chandelier  100  contains a number of arms  110 , each supporting a heat sink apparatus  10  in the same manner it would a conventional light bulb. From  FIG. 2 , it can be observed that the heat sink apparatus  10  can be used in conjunction with almost any conventional solid state light, including those used with many common consumer applications. 
     While the heat sink apparatus  10  is illustrated in  FIGS. 1A-1B  as having a flat bottom portion  75 , it can be observed that the bottom portion  75  can be of any shape and configuration compatible with a heat sink. In particular, the bottom portion  75  can be rounded, as shown in  FIG. 2 . 
     One of ordinary skill in the art will realize that the invention is not limited to the generally vertical configuration of  FIGS. 1A-1B , but rather encompasses heat sinks that can be oriented in any manner, so long as they are still able to dissipate heat from their associated solid state lights. In particular, the invention includes generally horizontal heat sink configurations.  FIGS. 3A-3C  are side, bottom, and top views, respectively, of a heat sink apparatus for use with solid state lights in accordance with further embodiments illustrating such horizontal configurations. Here, heat sink apparatus  200  includes generally the same configuration of elements as the heat sink apparatus of  FIGS. 1A-1B , except that the fins  60  extend generally circumferentially from the elongated portion  50 . Such circumferentially arranged fins  60  maximize the amount of surface area exposed to rising air when the heat sink apparatus  200  is oriented horizontally, thus maximizing the amount of heat dissipated from the solid state light  30 . 
     One of ordinary skill in the art will also observe that the invention includes configurations in which the solid state light  30  is separate from the heat sink apparatus  10 , as well as configurations in which the solid state light  30  is integrally formed with the heat sink apparatus  10 .  FIG. 4A  is a cutaway side view of heat sink apparatus  10 , illustrating the former configuration. For clarity in explanation, fins  60  and solid state light  30  are not shown. In the configuration of  FIG. 4A , the first end  20  is configured to be compatible with a separate solid state light  30 . For example, the interior of first end  20  can be sized and threaded to allow a standard solid state light to be screwed in. That is, the first end  20  can be configured as a screw base for accepting the cap or sleeve of any commercially-available solid state light. Alternatively, the first end  20  can be configured with a conventional socket, where the solid state light is threaded into the socket. In either case, the invention contemplates heat sinks capable of connecting to any known solid state light. For instance, the invention includes first ends  20  sized and threaded for, or configured with a socket for, accepting a solid state light with any Edison screw base. In particular, it is contemplated that heat sink apparatuses  10  employed in the United States can be configured to accept any one or more of E5, E10, E11, E12, E17, E26, E26D, E29, and E39 screw bases, BA15S and BA15D bayonet bases, and G4 and GY6.35 bi-pin bases, while heat sink apparatuses  10  employed in other locations, including Europe, can be configured to accept any one or more of E10, E11, E14, E27, and E40 screw bases, BA15S and BA15D bayonet bases, and G4 and GY6.35 bi-pin bases. 
     The configuration of  FIG. 4A  can also include a power cord  300  extending from a power source, a driver  310  for converting power to levels appropriate for the particular solid state light  30  employed, and a power line  320  running from the driver  310  and supplying power to the solid state light. If the first end  20  is configured with a socket, the power line  320  is connected to the socket. If the first end  20  is configured to directly accept a solid state light  30 , the power line  320  can connect directly to the solid state light  30 . The driver  310  can be any device or circuitry for converting electrical power to appropriate levels, and can be located either in (or attached/proximate to) the second end  40  or remotely, such as within the body of chandelier  100 . If the driver  310  is located remote from the remainder of the heat sink apparatus  10 , the power line  320  may not be necessary, and the power cord  300  can instead run directly to the first end  20 . 
       FIG. 4B  is a cutaway side view of heat sink apparatus  330 , illustrating the latter of the configurations described above, in which the solid state light  30  is integrally formed with the heat sink apparatus  10 . As in  FIG. 4A , fins  60  are not shown, for clarity in explanation. In the configuration of  FIG. 4B , the first end  20  is integrally formed with a solid state light  30 , so that the solid state light  30  itself does not have a screw base. Instead, a screw, bayonet or bi-pin base  340  extends from the second end  40 , so that the entire heat sink apparatus  330  is configured to be installed into a light socket. As with the screw, bayonet and bi-pin bases described above, screw, bayonet or bi-pin base  340  can be any conventional lamp base, including an Edison screw base such as any of those listed above. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the invention. In other instances, well known devices are shown in block form in order to avoid unnecessary distraction from the underlying invention. Thus, the foregoing descriptions of specific embodiments of the present invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Rather, many modifications and variations are possible in view of the above teachings. For example, the invention contemplates heat sinks adapted for connection to and/or use with any solid state light, including LED lights. The invention also contemplates heat sinks configured as a separate component from a solid state light, as well as heat sinks formed as integral units with solid state lights. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.