Abstract:
An LED packaging structure and a production method thereof; the LED packaging structure includes an LED die placed on a metal substrate and packed with seal in conjunction with a transparent substrate to deliver advantages of compact, simplified process and long service life and provide significant advancement and industrial value when compared to the prior art.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    (a) Field of the Invention 
         [0002]    The present invention is related to an LED packaging structure and a production method thereof, and more particularly to a new technology of having a transparent substrate as one of LED packaging materials. 
         [0003]    (b) Description of the Prior Art 
         [0004]    A light-emitting diode (LED) having been comprehensively applied in various types of electronic products is related to a solid-state conductor device. It working principle involves two carriers separated from each other in the diode (i.e., electrons carrying negative electricity and electric holes carrying positive electricity) and direct conversion of electric energy into optical energy to produce optical energy when those electrons and electric holes are incorporated to each other as conducted through with a current by applying voltage to both ends of a positive electrode and a negative electrode disposed in a semiconductor. In a conventional LED packaging process including but not limited to Die Bond, Wire Bond, and Molding, wherein a LED die is bonded to a reflection cup or an SMD base of a circuit board with transparent glue or silver epoxy before being processed with connection between both positive and negative electrodes to the lead frame using a gold wire or aluminum wire bonder, and finally the LED is packed up with epoxy. Further improvement and breakthrough are justified to lead in the market in coping with further advancement and upgrading product competition strength even though those manufacturing processes of the prior art are not found with any major flaws. Therefore, the present invention discloses an innovative LED packaging structure and a manufacturing process thereof to improve the existing process, particularly, to simplify the process for further upgrading and advancing the perfection production technology of LED packaging. 
       SUMMARY OF THE INVENTION 
       [0005]    The primary purpose of the present invention is to provide an LED packaging structure and a production method thereof is to place the LED die on a metal substrate in conjunction with a transparent substrate and packed with seal to achieve a simplified manufacturing process by giving up existing processes of Wire Bond and Molding so to increase production capacity, lower production cost, and help mass production by lot. Furthermore, as carrying out the packaging for multiple units, circuitry can be produced on the transparent substrate without using a circuit board; size and area of the structure of the present invention are smaller than the conventional structure to provide an application range meeting all requirements; packaging with the seal yields excellent waterproof and dustproof properties and allowing vacuum packaging or inert gas filling to extend service life; and permitting larger area of bonding of multiple units before breaking to meet mass production by lot. 
         [0006]    Another major niche provided by the LED packaging structure of the present invention rests in that manufacturers do not have to purchase new facilities and are able to carry out most of the process of the present invention with the exiting TFT LCD manufacturing facilities thus to significantly reduce development costs of facilities, fast introduction into production for time efficiency, and to catch from behind in case of a manufacturer with manufacturing technology falling behind or to expand leading edge in case of a manufacturer already leading in the manufacturing technology. 
         [0007]    Another innovation and only first seen in this art about the present invention is that LED light emitting characteristics can be changed simply by having either side of the transparent substrate coated with a thin film or covered up with a fluorescent material. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a perspective view of a first preferred embodiment of the present invention. 
           [0009]      FIG. 2  is an exploded view of the first preferred embodiment of the present invention. 
           [0010]      FIG. 3  is a sectional view of the first preferred embodiment of the present invention. 
           [0011]      FIG. 4  is a magnified view showing a local part of the first preferred embodiment of the preset invention. 
           [0012]      FIG. 5  is a perspective view of a second preferred embodiment of the present invention. 
           [0013]      FIG. 6  is an exploded view of the second preferred embodiment of the present invention. 
           [0014]      FIG. 7  is a sectional view of the second preferred embodiment of the present invention. 
           [0015]      FIG. 8  is a schematic view showing that the present invention is applied in RGB multi-chip package. 
           [0016]      FIG. 9  is a perspective view showing the present invention is combined with multiple connection elements and a heat sink. 
           [0017]      FIG. 10  is an exploded view showing that the present invention is combined with multiple connection elements and the heat sink. 
           [0018]      FIG. 11  is a sectional view showing that the present invention is combined with multiple connection elements and a heat sink. 
           [0019]      FIG. 12  is a schematic view showing that the present invention is applied in an LED light bar. 
           [0020]      FIG. 13  is an equivalent circuit diagram showing wiring for connection among multiple LEDs of the application illustrated in  FIG. 12 . 
           [0021]      FIG. 14  is a schematic view showing that the present invention is applied in a local area package. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0022]    Referring to  FIGS. 1 ,  2 ,  3 , and  4 , an LED packaging structure and a manufacturing method of the structure is comprised of a metal substrate  11 , which is related to Al or other heat conductive material; a die  12  is fixed at where appropriately to the metal substrate  11 ; a transparent substrate  13  made of a vitreous material, a transparent substance or a transparency is overlapped on a top of the die  12 ; and at where between the metal substrate  11  and the transparent substrate  13 , a seal  14  is used to pack where surrounding the die  12 . 
         [0023]    In the die  12 , an underfill  121  is used to bond the LED substrate  122  and the metal substrate  11 ′ a P-electrode  123 , an N-electrode  124 , and a bond  125  are formed on the LED substrate  122 , a through hole  131  is drilled over each bond  125  on the transparent substrate  13  disposed on top of the die  12 . The through hole contains a conductive material  132  and a conductive layer is laminated on an inner wall of the through hole  131 . The conductive material is printed or dispensed with a conductive epoxy, e.g., silver epoxy, solder paste, and solder ball, and printing or dispense of the conductive epoxy may be provided in a vacuum chamber to prevent residual air bulbs in the through hole. 
         [0024]    A conductive layer needs to be deposed and patterned on the transparent substrate  13 , and the conductive layer may be provided using metal, e.g., Al, Cr, or IndiumTin Oxide (ITO). Whereas the ITO is related to a transparent material, it is capable of increasing aperture ratio and manufacturing of circuit for the LED. 
         [0025]    A contact circuit  133  is disposed by the through hole  131  over, below, or over and below the transparent substrate  13 . 
         [0026]    The metal substrate  11  in the first preferred embodiment is related to a flat one, and the metal substrate  11  of a second preferred embodiment of the present invention as illustrated in  FIGS. 5 ,  6 , and  7  has a dent at its center, i.e., a trough  115  is formed at where the die  12  is placed to realize a special combination method by insertion. A seal  141  is fully coated on all contact surfaces found between the metal substrate  11  and the transparent substrate  13  to allow the present invention particularly suitable for mass production by lot or for packaging production of LED trim. 
         [0027]      FIG. 8  shows a schematic view of a structure of having RGB multi-chip packaging in assorted colors for the LED of the present invention. 
         [0028]    As illustrated in  FIGS. 9 ,  10 , and  11 , an LED packaging structure  2  is combined to a heat sink  4  through a connection unit  3 . The heat sink  4  includes multiple fins  41  and multiple locking holes  42  are disposed at where appropriately on the heat sink  4 . An accommodation trough  31  is formed in a bottom of the connection unit  3  to receive the LED packaging structure in position. A through hole  30  is disposed at a center of the connection unit  3  to allow irradiation from a light source of the LED packaging structure  2 ; the through hole  30  is covered up with a lens  32 ; multiple conductive plates  33  are disposed to the combination unit  3  to electrically connect to a wiring of the LED packaging structure  2 ; and the connection unit  3  is locked in those locking holes  42  on the heat sink  4  with corresponding fasteners  34 . 
         [0029]    As illustrated in  FIG. 12 , the present invention is made into an LED light bar  5  as applicable, and wiring among multiple LEDs may be directly connected, i.e., an equivalent circuit  6  as illustrated in  FIG. 13 . 
         [0030]    The LED packaging structure of the present invention may be provided as a single package as described in the first and the second preferred embodiments above, or in a local area package as illustrated in  FIG. 14 . Within the same seal  14 , multiple dies are provided to permit larger area of multiple units to be bonded first before cutting into multiple breaks to meet mass production by lot.