Abstract:
The disclosure provides a heat sink for electrical elements and a light-emitting device containing thereof. The heat sink includes a radiating substrate and at least one hollow radiating channel. In which, the hollow radiating channel is horizontally embedded in the radiating substrate, and has two openings disposed on the same site or the opposite sites of the radiating substrate, so that gas may flow in the hollow radiating channel and remove heat of the radiating substrate. And a light-emitting device containing the heat sink is also provided.

Description:
RELATED APPLICATIONS 
     This application claims priority to Taiwan Application Serial Number 102133408 filed Sep. 14, 2013, which is herein incorporated by reference. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a heat sink, and more particularly, to a heat sink for electrical elements and a light-emitting device containing thereof. 
     2. Description of Related Art 
     A general heat sink conducts the heat generated by an electronic device through thermal conductive material making up the heat sink to distribute the heat to a lower temperature portion of the heat sink, and then dissipate the heat into the air by thermal exchange between the air and a surface of the heat sink. In the heat sink, the average temperature of the whole electronic device is commonly deceased by such heat conduction to avoid any thermal damage of the electronic device from overheat. 
     However, poor thermal conductivity of the heat sink or thermal exchange between the air and the surface of the heat sink may results in heat accumulation in the electronic device which overheats and fails the electronic device. 
     Therefore, there is a need for an improved heat sink and a light-emitting device containing thereof, so as to solve the aforementioned problems met in the art. 
     SUMMARY 
     The present disclosure provides a heat sink for electrical elements and a light-emitting device containing thereof, to solve the problems met in the art. 
     One embodiment of the present disclosure is to provide a heat sink for electrical elements. The heat sink comprises a thermal conductive substrate and at least one hollow ventilation channel. The hollow ventilation channel is horizontally embedded in the thermal conductive substrate, and has two openings respectively on the same side or two different sides of the thermal conductive substrate, so that air can flow in the hollow ventilation channel and take away the heat of the thermal conductive substrate. 
     According to one embodiment of the present disclosure, the heat sink further comprises a composite material layer which is formed on the inner wall of the hollow ventilation channel. 
     According to one embodiment of the present disclosure, the composite material layer comprises a porous material or a hygroscopic material. 
     According to one embodiment of the present disclosure, the composite material layer comprises a carbonaceous material, a polymer, a metal oxide or a combination thereof. 
     According to one embodiment of the present disclosure, the heat sink of further comprises a roughened surface which is formed on the inner wall of the hollow ventilation channel. 
     According to one embodiment of the present disclosure, the material of the thermal conductive substrate includes ceramics, metals or silicon materials. 
     According to one embodiment of the present disclosure, the thermal conductive substrate is a copper substrate or a silicon substrate. 
     According to one embodiment of the present disclosure, the two different sides of the thermal conductive substrate are two opposite sides or two adjacent sides. 
     Another embodiment of the present disclosure is to provide a light-emitting device. The light-emitting device comprises the aforementioned heat sink and at least one light-emitting element positioned on the heat sink. 
     According to one embodiment of the present disclosure, the light-emitting element is a light-emitting diode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
         FIG. 1A  is a three-dimensional view of a heat sink  100   a  according to one embodiment of the present disclosure; 
         FIG. 1B  is a three-dimensional view of a heat sink  100   b  according to one embodiment of the present disclosure; 
         FIG. 1C  is a three-dimensional view of a heat sink  100   c  according to one embodiment of the present disclosure; 
         FIG. 1D  is a three-dimensional view of a heat sink  100   d  according to one embodiment of the present disclosure; 
         FIG. 1E  is a three-dimensional view of a heat sink  100   e  according to one embodiment of the present disclosure; 
         FIG. 2A  is a schematic cross-sectional view of the heat sink  100   b  taken along the line A-A′ of  FIG. 1B ; 
         FIG. 2B  is the top view of the heat sink  100   b  of  FIG. 2B ; 
         FIG. 2C  is a schematic cross-sectional view of the heat sink  100   b  taken along the line C-C′ of  FIG. 1B ; 
         FIG. 3A  is an enlarged view of a hollow ventilation channel  120  of the region D in  FIG. 2C ; and 
         FIG. 3B  is an enlarged view of a hollow ventilation channel  120  of the region D in  FIG. 2C . 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments of the transparent conductive structure and a method for manufacturing the same of the present disclosure are discussed in detail below, but not limited the scope of the present disclosure. The same symbols or numbers are used to the same or similar portion in the drawings or the description. And the applications of the present disclosure are not limited by the following embodiments and examples which the person in the art can apply in the related field. 
     The singular forms “a,” “an” and “the” used herein include plural referents unless the context clearly dictates otherwise. Therefore, reference to, for example, a metal layer includes embodiments having two or more such metal layers, unless the context clearly indicates otherwise. Reference throughout this specification to “one embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Therefore, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Further, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be appreciated that the following figures are not drawn to scale; rather, the figures are intended; rather, these figures are intended for illustration. 
       FIG. 1A  is a three-dimensional view of a heat sink  100   a  according to one embodiment of the present disclosure. In  FIG. 1A , the heat sink  100   a  comprises a thermal conductive substrate  110   a  and a hollow ventilation channel  120  horizontally positioned in the thermal conductive substrate  110   a . The hollow ventilation channel  120  has two openings  122 , and the two openings  122  are respectively on two different sides of the thermal substrate  110   a . Therefore, air may flow in the hollow ventilation channel  120  and take away the heat of the thermal conductive substrate  110   a.    
     In  FIG. 1A , the two openings  122  of the hollow ventilation channel  120  are respectively on the opposite sides of the thermal conductive substrate  110   a . The top surface and the bottom surface of the thermal conductive substrate may further comprise a plurality of metal electrodes and a plurality of conductive pillars electrically connected to the metal electrodes. In one embodiment of the present disclosure, the top surface and the bottom surface of the thermal conductive substrate  110   a  respectively have metal electrodes  130 , and the metal electrodes  130  are electrically connected by a conductive pillar  132 , as shown in  FIG. 1A . 
     According to one embodiment of the present disclosure, the material of the thermal conductive substrate includes ceramics, metals or silicon materials. According to another embodiment of the present disclosure, the thermal conductive substrate is a copper substrate or a silicon substrate. 
       FIG. 1B  is a three-dimensional view of a heat sink  100   b  according to one embodiment of the present disclosure. In  FIG. 1B , the heat sink  100   b  comprises a thermal conductive substrate  110   b  and two hollow ventilation channels  120  parallel to each other and horizontally positioned in the thermal conductive substrate  110   b . Each one of the hollow ventilation channels  120  has two openings  122 , and the two openings  122  are respectively on opposite sides of the thermal substrate  110   b . Therefore, air may flow in the hollow ventilation channels  120  and take away the heat of the thermal conductive substrate  110   b . In one embodiment of the present disclosure, the heat sink has a thermal conductive substrate and a U-shaped hollow ventilation channel, wherein the U-shaped hollow ventilation channel has two openings on the same side of the thermal conductive substrate. 
     Further, in one embodiment of the present disclosure, the top surface and the bottom surface of the thermal conductive substrate  110   b  respectively have metal electrodes  130 , and the metal electrodes  130  are electrically connected by a conductive pillar  132 , as shown in  FIG. 1B . In one embodiment of the present disclosure, a light-emitting device comprises a heat sink and at least one light-emitting element on the heat sink. In one embodiment of the present disclosure, the light-emitting element may be bonded on the thermal conductive substrate and electrically connected to the metal electrode. In which, the light-emitting element may be a light-emitting diode. 
       FIG. 1C  is a three-dimensional view of a heat sink  100   c  according to one embodiment of the present disclosure. In  FIG. 1C , the heat sink  100   c  comprises a thermal conductive substrate  110   c  and three hollow ventilation channels  120  horizontally positioned in the thermal conductive substrate  110   c . Each one of the hollow ventilation channels  120  has two openings  122 , and the two openings  122  are respectively on opposite sides of the thermal substrate  110   c . Therefore, air may flow in the hollow ventilation channels  120  and take away the heat of the thermal conductive substrate  110   c.    
     In  FIG. 1C , two of the hollow ventilation channels  120  are parallel to each other, and the other hollow ventilation channel  120  is crisscrossed to the two hollow ventilation channels  120 , so as to increase the opportunity and direction of air flow. Further, in one embodiment of the present disclosure, the top surface and the bottom surface of the thermal conductive substrate  110   c  respectively have metal electrodes  130 , and the metal electrodes  130  are electrically connected by a conductive pillar  132 , as shown in  FIG. 1C . 
       FIG. 1D  is a three-dimensional view of a heat sink  100   d  according to one embodiment of the present disclosure. In  FIG. 1D , the heat sink  100   d  comprises a thermal conductive substrate  110   d  and two hollow ventilation channels  120  horizontally positioned in the thermal conductive substrate  110   d . Each one of the hollow ventilation channels  120  has two openings  122 , and the two openings  122  are respectively on opposite sides of the thermal substrate  110   d . Therefore, air may flow in the hollow ventilation channels  120  and take away the heat of the thermal conductive substrate  110   d.    
     Different from  FIG. 1B , the hollow ventilation channels  120  in  FIG. 1D  are positioned on a slant in the thermal conductive substrate  110   d , thus the two openings  122  of the hollow ventilation channels  120  are on the adjacent sides of the thermal conductive substrate  110   d . Further, in one embodiment of the present disclosure, the top surface and the bottom surface of the thermal conductive substrate  110   d  respectively have metal electrodes  130 , and the metal electrodes  130  are electrically connected by a conductive pillar  132 , as shown in  FIG. 1D . 
       FIG. 1E  is a three-dimensional view of a heat sink  100   e  according to one embodiment of the present disclosure. In  FIG. 1E , the heat sink  100   e  comprises a thermal conductive substrate  110   e  and two hollow ventilation channels  120  horizontally positioned in the thermal conductive substrate  110   e . Each one of the hollow ventilation channels  120  has two openings  122 , and the two openings  122  are respectively on opposite sides of the thermal substrate  110   e . Therefore, air may flow in the hollow ventilation channels  120  and take away the heat of the thermal conductive substrate  110   e.    
     In  FIG. 1E , the two hollow ventilation channels  120  are crisscrossed to each other to increase the opportunity and direction of air flow. Further, in one embodiment of the present disclosure, the top surface and the bottom surface of the thermal conductive substrate  110   e  respectively have metal electrodes  130 , and the metal electrodes  130  are electrically connected by a conductive pillar  132 , as shown in  FIG. 1E . 
       FIG. 2A  is a schematic cross-sectional view of the heat sink  100   b  taken along the line A-A′ of  FIG. 1B . In  FIG. 2A , the hollow ventilation channels  120  are horizontally positioned in the thermal conductive substrate  110   b , having two openings  122  respectively on opposite sides of the thermal substrate  110   b . Further, the metal electrodes  130  are individually positioned on the top surface and the bottom surface of the heat sink  100   b . In which, a metal electrode  130  on the top surface and a metal electrode  130  on the bottom surface may pair up and be electrically connected by a conductive pillar  132 . 
       FIG. 2B  is the top view of the heat sink  100   b  of  FIG. 2B . In  FIG. 2B , the two hollow ventilation channels  120  are parallel to each other and positioned in the thermal conductive substrate  110   b . Each one of the hollow ventilation channels  120  has two openings  122  respectively on opposite sides of the thermal conductive substrate  110   b . In one embodiment of the present disclosure, the hollow ventilation channels  120  are under the metal electrodes  130 , so as to fully absorb the heat generated by electronic elements to enhance the ventilation performance. 
       FIG. 2C  is a schematic cross-sectional view of the heat sink  100   b  taken along the line C-C′ of  FIG. 1B . In  FIG. 2C , the hollow ventilation channels  120  are under the metal electrodes  130 , so as to fully absorb the heat generated by electronic elements to enhance the ventilation performance. Further, the metal electrodes  130  are individually positioned on the top surface and the bottom surface of the heat sink  100   b . In which, a metal electrode  130  on the top surface and a metal electrode  130  on the bottom surface may pair up and be electrically connected by a conductive pillar  132 . 
       FIG. 3A  is an enlarged view of a hollow ventilation channel  120  of the region D in  FIG. 2C . In  FIG. 3A , the inner wall of the hollow ventilation channels  120  further comprises a composite material layer  310   a . In one embodiment of the present disclosure, the composite material layer  310   a  comprises a porous material or a hygroscopic material. 
     The porous material has greater specific area which may significantly enhance the heat exchanging efficiency between the heat sink and air, so as to increase the ventilation performance. On another way, when the hygroscopic material is used to absorb water vapor in air, the temperature of the heat sink may change gradually because of the high specific heat of water. Further, water has higher heat of evaporation, so that the heat of the heat sink may be more absorbed as evaporation of water. In one embodiment of the present disclosure, the composite material layer  310   a  includes a carbonaceous material, a polymer, a metal oxide or a combination thereof. 
       FIG. 3B  is an enlarged view of a hollow ventilation channel  120  of the region D in  FIG. 2C . In  FIG. 3B , the inner wall of the hollow ventilation channels  120  further comprises a roughened surface  310   b . The inner wall of the hollow ventilation channel  120  is roughened by a roughening process to generate a roughened surface  310   b . Compared with a smooth surface, the roughened surface has a greater specific area which may increase the heat exchanging efficiency between the heat sink and air and enhance the performance of ventilation. 
     In embodiments of the present disclosure, the heat sink has at least one hollow ventilation channel which may significantly enhance the heat exchanging efficiency between the heat sink and air, so as to increase the ventilation performance. Further, the hollow ventilation channel is horizontally positioned in the thermal conductive substrate, and has exposed openings keeping the air in circulation. 
     Although embodiments of the present disclosure and their advantages have been described in detail, they are not used to limit the present disclosure. It should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the present disclosure. Therefore, the protecting scope of the present disclosure should be defined as the following claims.