Patent Publication Number: US-8529098-B2

Title: Light emitting diode device with effective heat dissipation

Description:
BACKGROUND 
     Conventional light emitting diode (LED) devices often include several package-type components, depending on their application. One common component is a heat sink to dissipate heat generated during operation. Centralizing heat flux and the large thermal density of LEDs sometimes requires a heat sink with a large heat transfer area to dissipate the heat. Another common component is a waterproof housing to protect an internal power supply from water damage. Assembly of this housing can be difficult, and if the housing is damaged or the power supply is problematic, maintenance can be difficult. Yet another common component is a reflector to direct light (radiation) emanating from the LED through a central lens area. Often, light intensity is diminished as a result of this component. 
     There is a continuing need to improve LED devices, including their manufacture and operation. These improvements include, but are not limited to, improving one or more of the above-listed package-type components. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale and are used for illustration purposes only. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures. 
         FIGS. 1A-1D  show a light emitting diode (LED) device with a luminaire housing, in accordance with an embodiment of the present disclosure. 
         FIG. 2  shows a heat transfer method for the LED device with the luminaire housing, in accordance with an embodiment of the present disclosure. 
         FIGS. 3A and 3B  show sample simulation results for the LED device, in accordance with embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     It is understood that the present disclosure provides many different embodiments, and that these embodiments are provided only as examples of systems, devices and methods that can benefit from the present invention. The invention itself should not be limited to any of these embodiments. Also, in the drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. Furthermore, it will be understood that when an element or layer is referred to as being “on,” or “coupled to” another element or layer, it may be directly on, or coupled to the other element or layer, or intervening elements or layers may be present. 
     Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as being “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly. 
     Hereinafter, embodiments of the present invention will be explained in detail with reference to the accompanying drawings. 
     Embodiments of the present disclosure relate to a light emitting diode (LED) device having an improved luminaire housing with effective heat dissipation. In one aspect, the luminaire housing combines a heat sink and a vapor chamber together to provide effective heat dissipation by reducing thermal resistance and increasing heat transfer rate. In another aspect, use of the vapor chamber allows a reduced heat sink dimension along with other advantages as described in greater detail herein. 
       FIGS. 1A-1D  show a light emitting diode (LED) device  100  with a luminaire housing  110 , in accordance with an embodiment of the present disclosure. 
       FIG. 1A  shows the LED device  100  comprising the luminaire housing  110  with heat sink  112  and vapor chamber  114 , a control box  120  with heat sink  122 , a cover  130 , and one or more LED modules  140 .  FIG. 1B  shows a plurality of LED modules  140  attached to the luminaire housing  110 .  FIG. 1C  is an exploded view of the LED device  100 . As shown in  FIG. 1C , the LED device  100  comprises a controller and power supply  150 . 
     Referring to  FIG. 1B , the housing  110  comprises a lighting structure adapted to receive one or more LED modules  140  for attachment thereto. In one aspect, each of the LED modules  140  are adapted to be waterproof. The control box  120  is adapted to receive the housing  110  for attachment thereto. In one aspect, the housing  110  is adapted to be attached to the control box  120  for waterproof assembly. The control box  120  is adapted to receive the controller and power supply  150  for attachment thereto. The control box  120  is adapted to receive the cover  130  for attachment thereto. In one aspect, as shown in  FIG. 1C , the controller and power supply  150  are adapted to be attached to the control box  120  and enclosed by the cover  130  for waterproof assembly. In another aspect, as long as the LED modules  140  and the control box  120 , which has the installed controller and power supply  150 , have a waterproof function, the LED modules  140  may be directly mounted to the housing  110 . Accordingly, assembly of the LED device  100  is simplified because each component thereof is already waterproof prior to assembly. 
       FIG. 1D  shows assembly of the LED module  140  to the luminaire housing  110 . As shown in  FIG. 1D , the housing comprises one or more electrical connectors  142  that are adapted to receive an electrical connector  144  of each corresponding LED module  140 . In one aspect, each LED module  140  comprises at least one electrical connector  144  that corresponds to electrical connectors  142  of the housing  110  so that the housing is adapted to be electrically connected to a plurality of LED modules  140  as shown in  FIG. 1B . In another aspect, the electrical connectors  142 ,  144  are adapted to provide the LED modules  140  with an electrical connection to the controller and power supply  150  within the control box  120  for operation of the LED modules  140 . 
     As shown in  FIG. 1D , the LED modules  140  may be attached to the housing  110  with one or more fasteners  146 , such as screws, rivets, etc. In one aspect, the LED modules  140  may be directly and securely mounted to the housing  110  with the connectors  142  and/or the fasteners  146 . In another aspect, the LED modules  140  may be attached to the housing  110  with an adhesive, such as glue, resin, epoxy, etc., without departing from the scope of the present disclosure. 
     Referring to the housing  110 , the vapor chamber  114  may be adapted to transfer heat from the LED modules  140  to the heat sink  112  uniformly and quickly. The heat sink  112  is adapted to dissipate heat. In one aspect, some convection cooling of the LED modules  140  may occur, without departing from the scope of the present disclosure. 
     Referring to the control box  120 , the heat sink  122  is adapted to dissipate heat from the controller and power supply  150 . In one aspect, heat generated from the controller and power supply  150  may not be as high as heat generated from the LED modules  140 . In another aspect, the controller and power supply  150  is adapted to be waterproof. 
     In one embodiment, the LED modules  140  comprise one or more LED components  148  adapted to emit light when voltage from the power supply  150  is applied thereto. For example, as shown in  FIG. 1B , each LED module  140  may comprise a plurality of LEDs  148 , such as for example 6 LEDs. In one aspect, the LED modules  140  together generate a large amount of heat that may be dissipated through the heat sink  112  of the housing  110 . In another aspect, the LED modules  140  are adapted to be waterproof. 
       FIG. 2  shows a heat transfer method  200  for the luminaire housing  110  of the LED device  100 , in accordance with an embodiment of the present disclosure. In one aspect, as shown in  FIG. 2 , the housing  110  combines the heat sink  112  with the vapor chamber  114  to form an enclosed space  220  interposed therebetween. Accordingly, i.e., the vapor chamber  114  is adapted to form the enclosed space  220  in the housing  110  between the LED modules  140  and the heat sink  112 . In another aspect, the housing  110  is adapted to transfer heat from the LED modules  140  to the heat sink  112  via the vapor chamber  114 . 
     In one aspect, the LED modules  140  serve as a heat source by generating heat during operation, wherein generated heat transfers to the enclosed space  220  of the vapor chamber  112  from the LED modules  140 . The vapor chamber  114  comprises the enclosed space  220  that serves as a distributed heat source by uniformly dispersing the heat transferred from the LED modules  140  throughout the enclosed space  220 . The uniformly dispersed heat in the enclosed space  220  of the vapor chamber  112  transfers to the heat sink  112  in a uniform manner. The heat sink  112  serves to uniformly dissipate heat transferred from the enclosed space  220  of the vapor chamber  114 . 
     In one aspect, the vapor chamber  114  distributes heat flux rapidly so as to form a more uniform temperature field on the heat sink  112  to thereby provide effective heat dissipation. A more uniform distribution of temperature to the heat sink  112  via the vapor chamber  114  improves overall heat dissipation of the heat sink  112 . Conventional heat sink use provides non-uniform heat distribution in only a small area of a heat sink with a result of a small area of high temperature on the heat sink and a large area of low temperature on the heat sink, which is less efficient and thus ineffective. 
     In one implementation, the interior region of the enclosed space  220  of the vapor chamber  112  may comprise an empty space that may be filled with a working fluid, such as for example water, alcohol, etc. In one aspect, the fluid may fill the interior region defined by the enclosed space  220  of the vapor chamber  112 . In another aspect, the fluid may be circulated within the enclosed space  220  of the vapor chamber  112  to more uniformly disperse heat throughout the enclosed space  220 . In another aspect, under varying pressure, transferred heat may evaporate the fluid in the enclosed space  220  of the vapor chamber  112 , which may then condense when cooled or upon cooling. 
     In another implementation, the interior region of the enclosed space  220  of the vapor chamber  112  may comprise some type of porous material that may be filled with a working fluid, such as for example water, alcohol, etc. In one aspect, the porous material may fill the interior region defined by the enclosed space  220  of the vapor chamber  112 . The porous material may operate with a capillary action to circulate fluid therethrough. In another aspect, under varying pressure, transferred heat may evaporate the fluid in the enclosed space  220  of the vapor chamber  112 , which may then condense when cooled or upon cooling. The porous material may increase the speed at which droplets of fluid condense. 
       FIG. 3A  shows a sample simulation result  300  for temperature in degrees Celsius (° C.) versus time in seconds of the luminaire housing  110  with the heat sink  112  and the vapor chamber  114 , in accordance with an embodiment of the present disclosure. 
     As shown in  FIG. 3A , the housing  110  with the vapor chamber  114  is shown to stay cooler during the simulation  300  to at least less than approximately 32° C. over approximately 3600 seconds (i.e., 60 minutes). In one aspect, the housing  110  with the vapor chamber  114  is also shown to slowly rise in temperature at a slower rate during the simulation  300 . 
     Accordingly, as shown in  FIG. 3A , the LED luminaire housing  110  has significantly effective heat dissipation. In one aspect, the housing  110  combines the heat sink  112  and the vapor chamber  112  together to provide the enclosed space  200  for significantly effective heat dissipation. As such, the housing  110  is adapted to provide more effective heat dissipation by reducing thermal resistance and increasing the heat transfer rate. 
       FIG. 3B  shows another sample simulation result  302  for temperature in ° C. versus time in seconds of the luminaire housing  110  with only the heat sink  112  and without the vapor chamber  114 , in accordance with an embodiment of the present disclosure. 
     As shown in  FIG. 3B , the housing  110  without the vapor chamber  114  is shown to rise significantly in temperature during the simulation to approximately 70° C. over approximately 1000 seconds (i.e., about 16.5 minutes). In one aspect, the housing  110  without the vapor chamber  114  is also shown to rise rapidly to a higher temperature at a faster rate during the simulation  302  than the simulation  300  of  FIG. 3A . 
     Therefore, as shown in  FIG. 3B , the LED luminaire housing  110  without a vapor chamber  114  would have less effective heat dissipation. In one aspect, the housing  110  is simulated with only the heat sink  112 , which provides less effective heat dissipation. As such, the housing  110  without the vapor chamber  114  provides less effective heat dissipation by increasing thermal resistance and inhibiting the heat transfer rate. 
     As described herein, embodiments of the present disclosure relate to an LED device having a luminaire housing with effective heat dissipation. The luminaire housing combines a heat sink and a vapor chamber together to provide effective heat dissipation by reducing thermal resistance and increasing heat transfer rate. In one aspect, use of the vapor chamber allows a reduced heat sink dimension along with other advantages. 
     In one embodiment, provided is a light emitting diode (LED) device comprising a housing having a heat sink and a vapor chamber. The housing is adapted to combine the heat sink with the vapor chamber to form an enclosed space interposed therebetween. The LED device comprises one or more LED modules attached to the housing adjacent to the vapor chamber. The LED modules are adapted to emit light and heat during operation. The vapor chamber is adapted to uniformly disperse heat generated from the LED modules within the enclosed space to form a uniform temperature field on the heat sink to thereby provide effective heat dissipation. 
     In various implementations, the housing may include a control box with a heat sink and a cover adapted to enclose a controller and power supply. The housing may be adapted to be attached to the control box for waterproof assembly. The controller and power supply may be adapted to be attached to the control box and enclosed by the cover for waterproof assembly. The heat sink of the control box may be adapted to dissipate heat from the controller and power supply. The LED modules may be waterproof. Each LED module may include one or more LED components adapted to emit light when voltage from the power supply is applied thereto. The LED modules may be attached to the housing with one or more fasteners including one or more screws. 
     In various implementations, the housing includes one or more electrical connectors, and each LED module includes at least one electrical connector that corresponds to at least one electrical connector of the housing so that the housing is adapted to be electrically connected to the LED modules. The electrical connectors may be adapted to provide each LED module with an electrical connection to the controller and power supply within the control box for operation of the LED modules. The vapor chamber of the housing may be adapted to transfer heat from the LED modules to the heat sink. The heat sink of the housing may be adapted to dissipate heat. 
     In one implementation, an interior region of the enclosed space of the vapor chamber may comprise an empty space that may be filled with a fluid including at least one of water and alcohol. In another implementation, the interior region of the enclosed space of the vapor chamber may comprise a porous material that may be filled with a fluid including at least one of water and alcohol. The porous material may operate with a capillary action to circulate the fluid within the enclosed space of the vapor chamber. 
     In another embodiment, provided is a device comprising one or more LED modules adapted to emit light and generate heat during operation, a vapor chamber adapted to disperse heat generated from the LED modules, a heat sink adapted to dissipate heat from the vapor chamber, and a housing adapted to combine the heat sink with the vapor chamber to form an enclosed space to uniformly disperse heat in the vapor chamber and to form a uniform temperature field on the heat sink to thereby provide effective heat dissipation. 
     In still another embodiment, provided is a heat transfer method for an LED device comprising operating one or more light emitting diode modules to emit light, the light emitting diode modules generating heat during operation, transferring heat from the light emitting diode modules to a vapor chamber, dispersing heat from the light emitting diode modules throughout an enclosed space of the vapor chamber, transferring heat from the vapor chamber to a heat sink, and dispersing heat from the heat sink. In one aspect, the vapor chamber is adapted to uniformly disperse heat from the light emitting diode modules so as to form a uniform temperature field on the heat sink to thereby provide effective heat dissipation. 
     Although embodiments of the present disclosure have been described, these embodiments illustrate but do not limit the disclosure. It should also be understood that embodiments of the present disclosure should not be limited to these embodiments but that numerous modifications and variations may be made by one of ordinary skill in the art in accordance with the principles of the present disclosure and be included within the spirit and scope of the present disclosure as hereinafter claimed.