Abstract:
An LED package comprises a substrate, an LED die, and an encapsulating layer. The substrate has circuit formed thereon. The LED die is arranged on the substrate and electrically connected to the circuit of the substrate. The encapsulating layer covers the LED die and at least a part of the substrate. The encapsulating layer and the substrate are made of cycloaliphatic epoxide.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure generally relates to LED technology, and particularly to an LED package. 
         [0003]    2. Description of the Related Art 
         [0004]    Light emitting diodes&#39; (LEDs&#39;) many advantages, such as high luminosity, low operational voltage, low power consumption, compatibility with integrated circuits, easy driving, long-term reliability, and environmental friendliness, have promoted the LEDs as a widely used light source. Light emitting diodes are commonly applied in lighting applications. 
         [0005]    LED packages must, however, overcome certain manufacturing challenges. Light transmissive resins for encapsulating semiconductor devices have heavily relied on blends of bisphenol-A epoxy and aliphatic anhydride curing agents. The materials used heretofore become discolored in extended storage at temperatures above 80° C., through yellow to brown, whereby their light transmittancy decreases considerably. Furthermore, because of the aromatic character of bisphenol-A based epoxy resins, these encapsulants would be less stable to ultraviolet component. Such degradation can lead to discoloration of the encapsulant, and accordingly reduce light transmittance and product lifetime. Other encapsulating material, such as silicone, also has problem of short product lifetime. 
         [0006]    What is needed, therefore, is an LED package which can increase product lifetime, and ameliorate the described limitations. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Many aspects of the disclosure can be better understood with reference to the drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the LED package. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the views. 
           [0008]      FIG. 1  is a schematic view of an LED package in accordance with a first embodiment. 
           [0009]      FIG. 2  is a schematic view of a different structure of an LED package in accordance with a first embodiment. 
           [0010]      FIG. 3  is a schematic view of another structure of an LED package in accordance with a first embodiment. 
           [0011]      FIG. 4  is a schematic view of an LED package in accordance with a second embodiment. 
           [0012]      FIG. 5  is a schematic view of a different structure of an LED package in accordance with a second embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    Embodiments of an LED package as disclosed are described in detail here with reference to the drawings. 
         [0014]    Referring to  FIG. 1 , an LED package  10  in accordance with a first embodiment includes a substrate  11 , a reflective cup  12 , an LED die  13 , and an encapsulating layer  14 . The substrate  11  is configured for supporting the LED die  13 . A circuit is arranged on the substrate  11  to provide electricity to the LED die  13 . 
         [0015]    In this embodiment, the substrate  11  and the reflective cup  12  are formed integrally. In another embodiment, the reflective cup  12  is separately formed from the substrate  11  and arranged on the substrate  11  for receiving the LED die  13  and improving light emitting efficiency of the LED die  13 . 
         [0016]    In this embodiment, the circuit of the substrate  11  includes a first electrode  112  and a second electrode  114  arranged on a first surface  110  of the substrate  11 . Two contacting electrodes  162  and  164  are arranged on another second surface  111  opposite to the first surface  110  of the substrate  11 . The first electrode  112  electrically connects with the first contacting electrode  162  through a first connecting electrode  166 . The second electrode  114  electrically connects with the second contacting electrode  164  through a second connecting electrode  168 . The first connecting electrode  166  and the second connecting electrode  168  are arranged on the side surface  113  between the first surface  110  and the second surface  112 . 
         [0017]    Referring to  FIG. 2 , the first electrode  112 , the first connecting electrode  166 , and the first contacting electrode  162  of  FIG. 1  are formed integrally as a monolithic first electrode  112 ′ in this alternative structure. The first end portion  1120  of the first electrode  112 ′ is arranged between the substrate  11  and the reflective cup  12  and exposed on the surface  110  of the substrate  11  on the bottom of the reflective cup  12  for electrically connecting with the LED die  13 . The main body  1122  of the first electrode  112 ′ extends on the side surface  113  outside the substrate  11 . The second end portion  1124  of the first electrode  112 ′ angles inwardly on the second surface  111  of the substrate  11  for electrically connecting with an outside circuit. 
         [0018]    The second electrode  114 , the second connecting electrode  168 , and the second contacting electrode  164  of  FIG. 1  are formed integrally as a monolithic second electrode  114 ′ in this alternative structure. The first end portion  1140  of the second electrode  114 ′ is arranged between the substrate  11  and the reflective cup  12  and exposed on the surface  110  of the substrate  11  on the bottom of the reflective cup  12  for electrically connecting with the LED die  13 . The main body  1142  of the second electrode  114 ′ extends on the side surface  113  outside the substrate  11 . The second end portion  1144  of the second electrode  114 ′ angles inwardly on the second surface  111  of the substrate  11  for electrically connecting with an outside circuit. 
         [0019]    The LED die  13  is arranged on the substrate  11  inside the reflective cup  12 . The positive and negative electrodes of the LED die  13  electrically connect with the first and second electrodes  112 ′,  114 ′ on the bottom of the reflective cup  12 . In this embodiment, the LED die  13  is arranged on the second electrode  114 ′, one electrode of the LED die  13  electrically connects with the second electrode  114 ′, and another electrode electrically connects with the first electrode  112 ′ through wire. 
         [0020]    The encapsulating layer  14  is arranged inside the reflective cup  12  and covering the LED die  13  and a part of the first surface  110  of the substrate  11 . The encapsulating layer  14  is composed of cycloaliphatic epoxide and can be made by resin transfer molding, injection molding, spot glue molding, or printing coating. The reflective cup  12  can further be doped with titanium dioxide (TiO 2 ) for improving light reflection. 
         [0021]    Preferably, the encapsulating layer  14  can further be doped with luminescent material, such as garnet compound, silicate compound, sulfide compound, or nitride compound. Moreover, the substrate  11  can be made of cycloaliphatic epoxide and glass fiber, and the reflective cup  12  and the encapsulating layer  14  composed of cycloaliphatic epoxide with resin transfer molding, or embedding molding. 
         [0022]    The reflective cup  12  is optional. An LED package can comprise the encapsulating layer  14  covering the LED die  13  and the first surface  110  of the substrate  11  without the reflective cup  12  as shown in  FIG. 3 . 
         [0023]    Referring to  FIG. 4 , an LED package  20  in accordance with a second embodiment includes a substrate  21 , a reflective cup  22 , an LED die  23 , and an encapsulating layer  24 . The substrate  21  is configured for supporting the LED die  23 . A circuit is arranged on the substrate  21  to provide electricity to the LED die  23 . In this embodiment, the substrate  21  and the reflective cup  22  are formed integrally. The reflective cup  22  is arranged on the substrate  21  for receiving the LED die  23  and improving light emitting efficiency of the LED die  23 . 
         [0024]    The circuit of the substrate  21  includes a first electrode  212  and a second electrode  214  respectively embedded in the substrate  21 . The first electrode  212  and the second electrode  214  pass through the first surface  210  and the second surface  211  of the substrate  21 . In this embodiment, the end surfaces of the first electrode  212  and the second electrode  214  are coplanar with the first surface  210  and the second surface  211 . The first electrode  212  and the second electrode  214  are made of conductive metals and electrically isolated by insulating material  216 . One end of the first electrode  212  and the second electrode  214  is exposed through the first surface  210  of the substrate  21  for electrically connecting with the LED die  23 . The other end of the first electrode  212  and the second electrode  214  extends outside the substrate  21  on the second surface  211  for electrically connecting with an outside circuit. 
         [0025]    The LED die  23  is arranged on the substrate  21  inside the reflective cup  22 . The positive and negative electrodes of the LED die  23  are electrically connecting with the first electrode  212  and the second electrode  214  on the bottom of the reflective cup  22 . In this embodiment, the LED die  23  is arranged on the second electrode  214 , one electrode of the LED die  23  electrically connecting with the second electrode  214 , and another electrode electrically connecting with the first electrode  212  through wire. 
         [0026]    The encapsulating layer  24  is arranged inside the reflective cup  22  and covers the LED die  23  and a part of the first surface  210  of the substrate  21 . The encapsulating layer  24  is composed of cycloaliphatic epoxide and can be made by resin transfer molding, injection molding, spot glue molding, or printing coating. The reflective cup  22  can further be doped with titanium dioxide (TiO 2 ) for improved light reflection. 
         [0027]    Preferably, the encapsulating layer  24  can further be doped with luminescent material, such as garnet compound, silicate compound, sulfide compound, or nitride compound. Moreover, the substrate  21  can be made of cycloaliphatic epoxide and glass fiber, and the reflective cup  22  and the encapsulating layer  24  are composed of cycloaliphatic epoxide with resin transfer molding, or embedding molding. The first electrode  212 , the second electrode  214 , and the insulating material  216  can be made by heat lamination or embedding molding. The reflective cup  22  can be made by transfer molding or injection molding. 
         [0028]    The reflective cup  22  is optional. An LED package can comprise the encapsulating layer  24  covering the LED die  23  and the first surface  210  of the substrate  21  without the reflective cup  22  as shown in  FIG. 5 . 
         [0029]    It is to be understood, however, that even though numerous characteristics and advantages of the disclosure have been set forth in the foregoing description, together with details of the structures and functions of the embodiment(s), the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.