Abstract:
An LED package includes a base, an LED chip disposed on the base, a liquid heat conducting layer and a sealing member. The LED chip is sealed from liquid. The liquid heat conducting layer surrounds and covers the sealed LED chip. The sealing member is arranged on the substrate and encloses and seals the liquid heat conducting layer therein. The LED chip is sealed by a phosphor layer on a top surface thereof and a heat conductive layer on a side surface thereof.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The disclosure relates to light emitting diode (LED) packages, and particularly to an LED package with great heat dissipating capability and a method of manufacturing the LED package. 
         [0003]    2. Discussion of Related Art 
         [0004]    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 their wide use as a lighting source. 
         [0005]    A typical LED package includes a substrate, an LED arranged on the substrate, an annular reflecting cup disposed on the substrate and surrounding the LED chip, and an encapsulant received in the reflecting cup and covering the LED. However, it is well known that heat is generated by the LED chip during operation. If the LED package is used in a state of high temperature for a long time, the life thereof is dramatically shortened. 
         [0006]    Therefore, what is needed is an LED package which can overcome the described limitations. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0008]      FIG. 1  is a schematic, cross-sectional view of an LED package according to an exemplary embodiment of the present disclosure. 
           [0009]      FIGS. 2 to 5  are cross-sectional views showing different steps of an embodiment of a method for manufacturing the LED package of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0010]    Referring to  FIG. 1 , an LED package  10  in accordance with an exemplary embodiment of the present disclosure is illustrated. The LED package  10  includes a substrate  11 , an LED chip  12  mounted on the substrate  11 , a side conductive layer  13  surrounding the LED chip  12 , a phosphor layer  14  arranged on the LED chip  12 , a sealing member  16  surrounding and covering the LED chip  12 , and a liquid heat conductive layer  15  sealed in the sealing member  16 . 
         [0011]    In the present embodiment, the substrate  11  is a rectangular plate made of polyphthalamide (PPA). An annular side conductive plate  111  is arranged on the substrate  11 . The side conductive plate  111  is made of metal. Alternatively, the side conductive plate  111  can be made of polyphthalamide (PPA), and can be integrally formed with the substrate  11  as a single piece. In the present embodiment, a circuit layer (not shown) is arranged on the substrate  11 . 
         [0012]    A connecting layer  122  is mounted on the substrate  11  and received in the side conductive plate  111 . In the present embodiment, the connecting layer  122  is made of a good heat conductive material, such as copper, aluminum or alloy thereof, for transferring heat from the LED chip  12  to the substrate  11  efficiently. The LED chip  12  is mounted on the connecting layer  122  via eutectic bonding. The LED chip  12  is electrically connected to an external power supply via the circuit layer. The LED chip  12  includes a light emitting surface  123  away from the substrate  11 . 
         [0013]    The side conductive layer  13  is annular and arranged on the substrate  11  for surrounding side surfaces of the LED chip  12 . In the present embodiment, the light emitting surface  123  is substantially coplanar with a top surface  131  of the side conductive layer  13 . The side conductive layer  13  is made of a good heat conductive material, for transferring heat from the LED chip  12  to the liquid heat conductive layer  15  efficiently. In the present embodiment, the side conductive layer  13  is made of copper. The phosphor layer  14  is arranged on the light emitting surface  123  of the LED chip  12  and the top surface  131  of the side conductive layer  13 . The phosphor layer  14  can be selected from garnet phosphor, silicate phosphor, or sulphide phosphor. The phosphor layer  14 , the side conductive layer  13  and the substrate  11  cooperatively seal the LED chip  12  therebetween. As a result, a sealed LED chip  12  is formed for preventing damage of the LED chip  12  due to entrance of the liquid heat conductive layer  15  into the LED chip  12 . Alternatively, the LED chip  12  can be sealed by a typical method, such as coating a waterproof layer or a sealant thereon. 
         [0014]    The sealing member  16  has an arc shaped and engaged with an upper surface  113  of the side conductive plate  111  to form a sealed chamber among the sealing member  16 , the substrate  11  and the side conductive plate  111 . In the present embodiment, the sealing member  16  is made of transparent material, such as glass. The liquid heat conductive layer  15  is sealed in the sealing member  16  and covers the sealed LED chip  12 . The liquid heat conductive layer  15  is made of a good heat conductive material. The liquid heat conductive layer  15  is liquid, and can transfer heat generated from the LED chip  12  to the ambient atmosphere via the sealing member  16 . 
         [0015]    A part of heat generated from the LED chip  12  is transferred to the ambient atmosphere via the liquid heat conductive layer  15 , and the other part of heat generated from the LED chip  12  is transferred to the substrate  11  via the connecting layer  122 , and then dissipate to the ambient atmosphere; therefore, a heat dissipating capability, and lifespan of the LED package  10  is improved. In addition, since the sealing member  16  is made of glass, it can improve the mechanical strength of the LED package  10 . 
         [0016]    Referring to  FIGS. 2-5 , a method for manufacturing the LED package  10  in accordance with an exemplary embodiment is also disclosed, and includes: 
         [0017]    Step 1: referring to  FIG. 2 , providing a substrate  11 , mounting an annular side conductive plate  111  on the substrate  11 , and forming a first metal layer  112  on the substrate  11  wherein the first metal layer  12  is received in a space surrounded by the side conductive plate  111 . In the present embodiment, a circuit layer (not shown) is arranged on the substrate  11 . The side conductive plate  111  has an upper surface  113  away from the substrate  11 . 
         [0018]    Step 2: referring to  FIG. 3  also, providing an LED chip  12 , forming a second metal layer  121  on a bottom surface of the LED chip  12 , and then mounting the LED chip  12  on the first metal layer  112  to make the second metal layer  121  connected to the first metal layer  112  by eutectic bonding thereby to secure the LED chip  12  on the substrate  11 . In the present embodiment, the first metal layer  112  and the second metal layer  121  each are made of a good heat conductive material, such as copper, aluminum or alloy thereof, for transferring heat from the LED chip  12  to the substrate  11  efficiently. The first metal layer  112  is cooperated with the second metal layer  121  to form a connecting layer  122  for dissipating heat generated from the LED chip  12 . The LED chip  12  is electrically connected to an external power supply via the circuit layer. The LED chip  12  has a light emitting surface  123  away from the substrate  11 . 
         [0019]    Step 3: forming an annular side conductive layer  13  surrounding side surfaces of the LED chip  12 . In the present embodiment, the light emitting surface  123  is substantially coplanar with a top surface  131  of the side conductive layer  13 . The side conductive layer  13  is made of a good heat conductive material. In the present embodiment, the side conductive layer  13  is made of copper. In the present embodiment, the side conductive layer  13  can be formed on the side surfaces of the LED chip  12  via electroplating. 
         [0020]    Step 4: referring to  FIG. 4 , forming a phosphor layer  14  on the light emitting surface  123  of the LED chip  12  and the top surface  131  of the side conductive layer  13  to seal the LED chip  12 . The phosphor layer  14  can be excited by light from the LED chip  12  to generate a light with a wavelength different from that of the light generated by the LED chip  12 . 
         [0021]    Step 5: referring to  FIG. 5  and  FIG. 1 , forming a liquid heat conductive layer  15  covering the sealed LED chip  12 , and mounting a sealing member  16  on the upper surface  113  of the side conductive plate  111  for sealing the liquid heat conductive layer  15 . In the present embodiment, the sealing member  16  is made of transparent material, such as glass. The liquid heat conductive layer  15  is sealed in the sealing member  16  and covers the sealed LED chip  12 . The liquid heat conductive layer  15  is made of a good heat conductive material. The liquid heat conductive layer  15  is liquid, and can transfer heat generated from the LED chip  12  to the ambient atmosphere via the sealing member  16 . 
         [0022]    In step 5, according to the present disclosure, the method can mount the sealing member  16  on the upper surface  113  of the side conductive plate  111  first, and then inject the liquid heat conductive layer  15  into the chamber sealed by the sealing member  16 ; 
         [0023]    or it can form the liquid heat conductive layer  15  to cover the sealed LED chip  12  via glue dispensing first, and then mount the sealing member  16  on the upper surface  113  of the side conductive plate  111  to seal the liquid heat conductive layer  15  therein. 
         [0024]    It is to be further understood that even though numerous characteristics and advantages have been set forth in the foregoing description of embodiments, together with details of the structures and functions of the embodiments, the disclosure is illustrative only; and that 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.