Patent Publication Number: US-2015085503-A1

Title: Lighting apparatus

Description:
TECHNICAL FIELD 
     The present disclosure relates to an illuminating device, and more particularly, to an illuminating device using a light emitting device as a light source. 
     BACKGROUND ART 
     A light emitting diode (LED) is a semiconductor light emitting device capable of implementing light of various colors through the use of various compound semiconductor materials such as GaAs, AlGaAs, GaN, InGaInP, and the like. 
     Since LEDs have several advantages such as excellent monochromic peak wavelengths, excellent optical efficiency, compactness, environmental friendliness, low power consumption, and the like, LEDs have increasingly been applied to various devices such as TVs, computers, illuminating devices, automobiles, and the like, and fields of application thereof have been broadened. 
     Illuminating devices using LEDs are becoming increasingly prominent in these fields, since they have a relatively long lifespan compared to incandescent lamps or halogen lamps. 
     However, LEDs generate a large amount of heat depending on magnitudes of current applied thereto, and the heat may cause reductions in light emitting efficiency and lifespan. 
     In order to secure a long lifespan of the illuminating device, research into a structure optimized for heat dissipation is required, and research for structural improvement in efficient heat dissipation is being actively conducted. 
     DISCLOSURE 
     Technical Problem 
     An aspect of the present disclosure may provide an illuminating device having a simple structure, increasing an amount of light output of a light emitting device and extending a lifespan by improving heat dissipation. 
     Technical Solution 
     According to an aspect of the present disclosure, an illuminating device may include: a light source module including a substrate and at least one light emitting device package mounted on the substrate; a heat radiator including a heat radiating plate having a cavity provided at a center thereof open toward a front surface thereof and receiving the light source module therein and a plurality of ventilation holes disposed along an edge of the cavity, and a plurality of heat radiating fins extending to a rear surface of the heat radiating plate and disposed in a radial manner along an edge of the heat radiating plate to dissipate heat generated by the light source module, and positioned between the plurality of ventilation holes to form ventilation channels therebetween communicating with the plurality of ventilation holes; a cooler fixed to the heat radiator to be in contact with ends of the heat radiating fins and including a plurality of air jet holes in a surface thereof such that air is blown to the heat radiator; and an electrical connector connected to the light source module and the cooler and supplying an external electrical signal to the at least one light emitting device package and the cooler. 
     The heat radiating plate may include a plurality of exhaust holes disposed along an inner circumferential surface of the cavity and communicating with the respective ventilation channels. 
     The cooler may include a main body having an internal space having a predetermined size and including the plurality of air jet holes in a surface thereof facing the heat radiating fins; a membrane structure disposed inside the main body and generating an air flow through a vertical rocking motion to allow the air to be blown to the heat radiating fins through the air jet holes; and an actuator driving the membrane structure to perform the vertical rocking motion when the electrical signal is applied thereto. 
     The plurality of air jet holes may be disposed along an edge of the main body and positioned between the plurality of heat radiating fins to allow the air to be blown between the respective heat radiating fins. 
     The illuminating device may further include a cover member disposed on the front surface of the heat radiating plate to cover the cavity and protect the light source module. 
     The cover member may include an insertion hole provided in a position corresponding to the at least one light emitting device package to allow a portion of the at least one light emitting device package to be exposed to the outside. 
     According to another aspect of the present disclosure, an illuminating device may include a light source module including a substrate and at least one light emitting device package mounted on the substrate; a cooler having the light source module mounted on a surface thereof and cooling the light source module when a refrigerant injected thereinto is evaporated and discharged as vapor; a heat radiator including a heat radiating plate having a cavity provided at a center thereof open toward a front surface thereof and receiving the light source module and the cooler therein and a plurality of ventilation holes disposed along an edge of the cavity, and a plurality of heat radiating fins extending to a rear surface of the heat radiating plate, disposed in a radial manner along an edge of the heat radiating plate, and positioned between the plurality of ventilation holes to form ventilation channels therebetween communicating with the plurality of ventilation holes; and an electrical connector connected to the light source module and the cooler and supplying an external electrical signal to the at least one light emitting device package and the cooler. 
     The heat radiating plate may include a plurality of exhaust holes disposed along an inner circumferential surface of the cavity to communicate with the respective ventilation channels. 
     The cooler may include a main body having a reservoir receiving the refrigerant through a supply pipe and having a predetermined size, and an evaporation space communicating with the reservoir through a plurality of nozzles and allowing the refrigerant injected through the plurality of nozzles to be evaporated and discharged as vapor through a discharge pipe; and a condenser connected to the supply pipe and the discharge pipe to supply the refrigerant to the reservoir and receive the evaporated vapor from the evaporation space. 
     The supply pipe and the discharge pipe may be disposed in a surface of the main body opposite to the surface thereof on which the light source module is mounted. 
     The illuminating device may further include a pump allowing the refrigerant inside the condenser to be supplied to the reservoir through the supply pipe. 
     The illuminating device may further include a cover member disposed on the front surface of the heat radiating plate to cover the cavity and protect the light source module. 
     The cover member may include an insertion hole provided in a position corresponding to the at least one light emitting device package to allow a portion of the at least one light emitting device package to be exposed to the outside. 
     Advantageous Effects 
     According to exemplary embodiments of the present disclosure, air circulation may be facilitated to allow heated air to be discharged without retention thereof, and heat dissipation efficiency may be maximized using latent heat of vaporization through a liquid-vapor phase change of a refrigerant, whereby a high-output LED illuminating device may be implemented. 
    
    
     
       DESCRIPTION OF DRAWINGS 
       The above and other aspects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is an exploded view illustrating an illuminating device according to an exemplary embodiment of the present disclosure; 
         FIG. 2  is a view illustrating a light source module and a cover member in the illuminating device of  FIG. 1 ; 
         FIG. 3  is a view illustrating a heat radiator in the illuminating device of  FIG. 1 ; 
         FIG. 4  is a view illustrating a cooler in the illuminating device of  FIG. 1 ; 
         FIG. 5  is a view schematically illustrating an operating principle of the cooler of  FIG. 4 ; 
         FIG. 6  is a view illustrating air flow in the heat radiator coupled to the cooler; 
         FIG. 7  is a view illustrating an illuminating device according to another exemplary embodiment of the present disclosure; 
         FIG. 8  is a view schematically illustrating a cooler in the illuminating device of  FIG. 7 ; and 
         FIG. 9  is a view schematically illustrating refrigerant flow in the cooler of  FIG. 7 . 
     
    
    
     BEST MODE 
     Exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. 
     The disclosure may, however, be exemplified in many different forms and should not be construed as being limited to the specific 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 disclosure to those skilled in the art. 
     In the drawings, the shapes and dimensions of elements may be exaggerated for clarity, and the same reference numerals will be used throughout to designate the same or like elements. 
     An illuminating device according to an exemplary embodiment of the present disclosure will be described in detail with reference to  FIGS. 1 through 6 . 
       FIG. 1  is an exploded view illustrating an illuminating device according to an exemplary embodiment of the present disclosure;  FIG. 2  is a view illustrating a light source module and a cover member in the illuminating device of  FIG. 1 ;  FIG. 3  is a view illustrating a heat radiator in the illuminating device of  FIG. 1 ;  FIG. 4  is a view illustrating a cooler in the illuminating device of  FIG. 1 ;  FIG. 5  is a view schematically illustrating an operating principle of the cooler of  FIG. 4 ; and  FIG. 6  is a view illustrating air flow in the heat radiator coupled to the cooler. 
     With reference to  FIGS. 1 through 6 , an illuminating device  1  according to an exemplary embodiment of the present disclosure may include a light source module  100 , a heat radiator  200 , a cooler  300  and an electrical connector  400 , and may further include a cover member  500  protecting the light source module  100 . 
     As illustrated in  FIGS. 1 and 2 , the light source module  100  may include a substrate  110  and at least one light emitting device package  120  mounted on the substrate  110 . 
     The light source module  100  may include a light emitting diode (LED), a semiconductor device capable of emitting light having a predetermined wavelength when an external electrical signal is applied thereto, as a light source, and the light emitting device package  120  may include a single LED or a plurality of LEDs disposed therein. 
     The substrate  110  may be a type of printed circuit board (PCB), and may be made of an organic resin material containing epoxy, triazine, silicon, polyimide, or the like, and other organic resin materials, or may be made of a ceramic material such as AlN, Al 2 O 3 , or the like, or a metal and a metal compound. For example, the substrate  110  may be a metal-core printed circuit board (MCPCB). 
     A circuit wiring (not shown) may be electrically connected to the light emitting device package  120  on a surface of the substrate  110  opposite to a mounting surface of the substrate  110  on which the light emitting device package  120  is mounted. The surface of the substrate  110  opposite to the mounting surface thereof may be assembled to the heat radiator  200  using a thermal interface material (not shown) such as a heat radiation pad, a phase change material, heat radiation tape, or the like, interposed therebetween, in order to decrease heat resistance. 
     The heat radiator  200  may serve as a housing accommodating and supporting the light source module  100 , as well as a heat sink dissipating heat generated in the light source module  100  externally. 
     As illustrated in  FIGS. 1 and 3 , the heat radiator  200  may include a heat radiating plate  210  having a cavity  211  open toward a front surface thereof to receive the light source module  100  therein, and a plurality of heat radiating fins  220  extending to a rear surface of the heat radiating plate  210  and disposed in a radial manner along an edge of the heat radiating plate  210 . 
     The heat radiating plate  210  may include a plurality of ventilation holes  212  formed along an edge of the cavity  211  defined at the center of the heat radiating plate  210 . The plurality of heat radiating fins  220  may be disposed between the plurality of ventilation holes  212 , and ventilation channels  222  may be formed between the plurality of heat radiating fins  220  to communicate with the plurality of ventilation holes  212 , respectively. 
     Therefore, air flowing through the ventilation channels  222  disposed between the heat radiating fins  220  may be discharged to the outside via the ventilation holes  212 , thereby cooling the heat radiating fins  220 . The ventilation channels  222  disposed in the radial manner may communicate with the respective ventilation holes  212 , thereby allowing a flow of heated air to be maintained without retention thereof. 
     In addition, the heat radiating plate  210  may include a plurality of exhaust holes  213  disposed along an inner circumferential surface of the cavity  211  to communicate with the respective ventilation channels  222 . That is, the exhaust holes  213  may be disposed in the inner circumferential surface of the cavity  211  to be adjacent to the light source module  100  received in the cavity  211 , thereby releasing the heat generated by the light emitting module  100  from the cavity  211  to the outside. 
     Since the exhaust holes  213  communicate with the respective ventilation channels  222 , air G heated by the heat generated in the light emitting module  100  may be discharged to the ventilation channels  222  via the exhaust holes  213  without being retained in the cavity  211 , whereby the temperature inside the cavity  211  may be lowered to cool the light source module  100 . 
     Meanwhile, the cooler  300  may be fixed to the heat radiator  200  to be in contact with rear ends of the heat radiating fins  220 , and may include a plurality of air jet holes  311  on a surface thereof such that the air G may be blown toward the heat radiator  200 . That is, the cooler  300  may forcibly create the air flow, thereby cooling the heat radiator  200 . Here, the air G may be blown via the air jet holes  311  in a micro air jet manner. 
     With reference to  FIGS. 4 and 5 , the cooler  300  may include a main body  310  having an internal space of a predetermined size, a membrane structure  320  disposed in the main body  310 , and an actuator  330  driving the membrane structure  320 . 
     The main body  310  may have a disk-shaped structure in contact with the rear ends of the heat radiating fins  220  disposed in the radial manner, and may have a size corresponding to an outer circumferential surface of an imaginary circle drawn by the heat radiating fins  220 ; however, the main body  310  is not limited thereto, and may have various shapes such as a polygonal shape. The plurality of air jet holes  311  may be formed to penetrate a surface of the main body  310  facing the heat radiating fins  220 . In this case, the plurality of air jet holes  311  may be disposed along an edge of the main body  310 . The air jet holes  311  may be positioned between the plurality of heat radiating fins  220 , so that the air G may be blown between the heat radiating fins  220 . 
     The membrane structure  320  may be disposed inside the main body  310 , generate the air flow through a vertical or horizontal rocking motion, and allow the air to be blown to the heat radiating fins  220  via the air jet holes  311 . The membrane structure  320  may be made of a material having elasticity such as rubber. 
     The actuator  330  may be a driving source allowing the membrane structure  320  to perform the vertical or horizontal rocking motion when an electrical signal is applied thereto. A stepping motor, a piezoelectric motor, or the like, may be used for the actuator  330 . The actuator  330 , along with the membrane structure  320 , may be disposed within the main body  310 . Alternatively, the actuator  330  may be disposed outside the main body  310 . 
     The cooler  300  according to the present embodiment may facilitate a wake effect caused by a vortex in the flow of the air forcibly blown into the ventilation channels  222  formed between the heat radiating fins  220  as illustrated in  FIG. 6 , thereby improving heat transfer on surfaces of the heat radiating fins  220  and maximizing a cooling effect of the heat radiating fins  220 . In addition, the cooler  300  may forcibly create the air flow through the ventilation channels  222 , so that the heat retained in the cavity  211  may be discharged to the outside due to a pressure difference between the inside and outside of the cavity  211  created by a forced flow field, whereby effective heat dissipation may be implemented. 
     The electrical connector  400  may supply an electrical signal to the light source module  100  and the cooler  300  through a switched mode power supply (SMPS)  420  disposed inside a housing  410 . The housing  410  may cover and protect the cooler  300  disposed at the rear of the heat radiating fins  220 . In this case, an outer surface of the housing  410  and outer surfaces of the heat radiating fins  220  may be continuously connected to one another along contact surfaces therebetween. 
     The cover member  500  may be disposed on the front surface of the heat radiating plate  210  to cover the cavity  211  and protect the light source module  100 . The cover member  500  may be made of polycarbonate (PC), plastic, silica, acryl, glass or the like. The cover member  500  may be made of a transparent material for light transmission, but is not limited thereto. 
     The cover member  500  may include insertion holes  510  formed in positions corresponding to the respective light emitting device packages  120 , as illustrated in  FIG. 2 , so that the insertion holes  510  allow portions of the light emitting device packages  120  to be exposed outwards. The insertion holes  510  may be disposed directly above the respective light emitting device packages  120  to allow upper portions of the light emitting device packages  120  to be inserted thereinto and be externally protruded to be exposed. 
     Meanwhile, an illuminating device according to another exemplary embodiment of the present disclosure will be described with reference to  FIGS. 7 through 9 . 
       FIG. 7  is a view illustrating an illuminating device according to another exemplary embodiment of the present disclosure.  FIGS. 8A and 8B  are views schematically illustrating a cooler in the illuminating device of  FIG. 7 , and  FIG. 9  is a view schematically illustrating refrigerant flow in the cooler of  FIG. 7 . 
     An illuminating device  1 ′ according to the embodiment of  FIG. 7  has substantially the same structure as that of the illuminating device  1  according to the embodiment of  FIG. 1 , except that a cooler  300 ′, along with the light source module  100 , is installed in the cavity  211  of the heat radiating plate  210  while being disposed between the light source module  100  and the heat radiator  200 , and cools the heat radiator  200  using a refrigerant instead of air. 
     With reference to  FIGS. 7 through 9 , the illuminating device  1 ′ according to the present embodiment may include the light source module  100 , the heat radiator  200 , the cooler  300 ′ and the electrical connector  400 , and may further include the cover member  500  protecting the light source module  100 . 
     The light source module  100  may include the substrate  110  and at least one light emitting device package  120  mounted on the substrate  110 . 
     The heat radiator  200  may include the heat radiating plate  210  having the cavity  211  open toward the front surface thereof and receiving the light source module  100  and the cooler  300 ′ therein, and the plurality of heat radiating fins  220  extending to the rear surface of the heat radiating plate  210  and disposed in a radial manner along the edge of the heat radiating plate  210 . 
     As illustrated, the heat radiating plate  210  may include the plurality of ventilation holes  212  formed along the edge of the cavity  211  provided at the center of the heat radiating plate  210 . The plurality of heat radiating fins  220  may be disposed between the plurality of ventilation holes  212 , and the ventilation channels  222  may be formed between the heat radiating fins  220  to communicate with the plurality of ventilation holes  212 . In addition, the heat radiating plate  210  may include the plurality of exhaust holes  213  disposed along the inner circumferential surface of the cavity  211  to communicate with the respective ventilation channels  222 . 
     The ventilation holes  212  and the exhaust holes  213  may communicate with the ventilation channels  222 , whereby air introduced through the ventilation holes  212  may flow through the ventilation channels  222  formed between the heat radiating fins  220  to cool the heat radiating fins  220 . In this case, the heated air flowing from the cavity  211  to the ventilation channels  222  may be discharged externally through the exhaust holes  213 , whereby heat release by natural convection may be facilitated. 
     Meanwhile, the cooler  300 ′ may be disposed within the cavity  211  while having the light source module  100  mounted on a front surface thereof. The cooler  300 ′ may have an internal space having a predetermined size, and when a refrigerant L injected into the internal space is evaporated and discharged as vapor, the cooler  300 ′ may forcibly cool the light source module  100 . 
     As illustrated in  FIG. 8A , the cooler  300 ′ may include a main body  310 ′ having a reservoir  312  and an evaporation space  311  that correspond to the internal space having the predetermined size, and a condenser  340  connected to the reservoir  312  and the evaporation space  311 . 
     The main body  310 ′ may have a cylindrical structure and the light source module  100  may be disposed to be in contact with the surface of the substrate  110  opposite to the mounting surface thereof on which the light emitting device packages  120  are mounted. A diameter of the main body  310 ′ may correspond to that of the inner circumferential surface of the cavity  211 , so that the main body  310 ′ may be installed in the cavity  211 . 
     The main body  310 ′ may include the reservoir  312  and the evaporation space  311  corresponding to the internal space having the predetermined size. The reservoir  312  and the evaporation space  311  may be separate spaces communicating with each other using a plurality of nozzles  313 . The evaporation space  311  may be adjacent to the surface of the main body  310 ′ on which the light source module  100  is mounted, such that the evaporation space  311  may be disposed between the light source module  100  and the reservoir  312 . 
     The reservoir  312  may receive the refrigerant L supplied from the outside of the main body  310 ′ through a supply pipe  315  and inject the received refrigerant L into the evaporation space  311  through the nozzles  313 . Here, the refrigerant L may be injected through the nozzles  313  in a micro liquid jet manner. The refrigerant L may be water, acetone, FC-72, or the like, but is not limited thereto. 
     The heat generated by the light source module  100  may be discharged to the outside when the refrigerant L injected through the nozzles  313  is evaporated as vapor in the evaporation space  311  due to the heat and is discharged to the outside of the evaporation space  311  through a discharge pipe  316 . That is, as illustrated in  FIG. 8B , vapor bubbles B may occur in the refrigerant L injected into the evaporation space  311  when nucleate boiling occurs, and a surface temperature of the evaporation space  311  may be lowered through a phase change during the nucleate boiling. 
     The supply pipe  315  and the discharge pipe  316  may be disposed in a surface of the main body  310 ′ opposite to the surface thereof on which the light source module  100  is mounted. The supply pipe  315  may be connected to the reservoir  312  and the discharge pipe  316  may be connected to the evaporation space  311 . 
     As illustrated in  FIGS. 7 and 9 , the condenser  340  may be connected to the discharge pipe  316 , such that the condenser  340  may receive the evaporated vapor and the heated refrigerant L from the evaporation space  311  through the discharge pipe  316 , releasing the heat and cooling the refrigerant L. In addition, the condenser  340  may resupply the refrigerant L to the reservoir  312 . 
     A pump  350  may be provided between the condenser  340  and the reservoir  312 , such that the refrigerant L within the condenser  340  may be supplied to the reservoir  312  through the supply pipe  315  using a predetermined amount of pressure from the pump  350 . In addition, a controller  360  may be further provided to control the operation of the pump  350 . 
     Since the cooler  300 ′ according to the present embodiment uses latent heat of vaporization through a liquid-vapor phase change of the refrigerant L, it may be relatively effective for dissipating heat of a high-power product, as compared to a liquid cooling method using sensible heat. 
     In addition, the heat radiating plate  210  and the heat radiating fins  220  having the cooler  300 ′ installed therein may allow the heat to be additionally discharged by natural convection, whereby heat dissipation efficiency may be further improved. 
     The electrical connector  400  may supply an electrical signal to the light source module  100  and the cooler  300 ′, particularly to the condenser  340  and the pump  350 , through the SMPS  420  disposed inside the housing  410 . The housing  410  may cover and protect the condenser  340  and the pump  350  disposed at the rear of the heat radiating fins  220 . In this case, the outer surface of the housing  410  and the outer surfaces of the heat radiating fins  220  may be continuously connected to one another along contact surfaces therebetween. 
     The cover member  500  may be disposed on the front surface of the heat radiating plate  210  to cover the cavity  211  and protect the light source module  100 . The cover member  500  may be made of polycarbonate (PC), plastic, silica, acryl, glass or the like. The cover member  500  may be made of a transparent material for light transmission, but is not limited thereto. 
     In particular, the cover member  500  may include the insertion holes  510  formed in positions corresponding to the respective light emitting device packages  120 , so that the insertion holes  510  allow portions of the light emitting device packages  120  to be exposed to the outside. The insertion holes  510  may be disposed directly above the respective light emitting device packages  120  to allow the upper portions of the light emitting device packages  120  to be inserted thereinto and be externally protruded to be exposed.