Abstract:
A surface-mount package for multiple LED chips is constructed by inscribing a groove in an insulating substrate. The LED chips are mounted in the groove and the leads are connected to metal plates, which wrap around the substrate to provide bottom contacts for surface-mounting.

Description:
BACKGROUND OF THE INVENTION 
     (1) Field of Invention 
     This invention relates to light emitting diodes (LED), particularly to packages for multiple LED chips. The package is also applicable to optical devices, such as laser diodes, etc. 
     (2) Brief Description of Related Art 
     FIG. 1 shows a prior art package for a single LED. A cup  16  is recessed in a substrate  15 . The bottom and the wall of the cup is coated with a layer of metal  11 . The LED chip  10  is mounted on the bottom of the cup  16 . The top electrode of the LED chip  10  is wire-bonded to the metallic plate  12  for extension connection. The bottom electrode of LED  10  is in contact with the metallic layer  11  which is extended to provide another external connection. FIG. 2 shows the side view of FIG.  1 . 
     The cup shaped structure shown in FIGS. 1 and 2 has only one cup and is incapable of accommodating multiple number of chips in one package. 
     SUMMARY OF THE INVENTION 
     An object of this invention is to provide a package capable of packaging multiple number of LED chips. 
     The object is achieved by inscribing a groove in the package so that more than one LED chips can be mounted in the groove. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 shows the top view of a prior art LED package. 
     FIG. 2 shows the side view of FIG.  1 . 
     FIG. 3 shows the top view of the grooved package of the present invention. 
     FIG. 4 shows the side view of FIG. 3, 
     FIG. 5 shows the bottom view of FIG.  3 . 
     FIG. 6 shows the mounting of two LED chips on a grooved package. 
     FIG. 7 shows the bottom view of FIG.  6 . 
     FIG. 8 shows wrapped around leads for surface mounting to a motherboard. 
     FIG. 9 shows lead connections of multiple LEDs with common bottom electrodes. 
     FIG. 10 shows lead connections of multiple LEDs with common top electrodes. 
     FIG. 11 shows lead connections of multiple LEDs with only bottom electrodes. 
     FIG. 12 shows lead connections of multiple LEDs with electrodes connected to leads alternately spaced at two side of the groove. 
     FIG. 13 shows the side view of a V-shaped groove. 
     FIG. 14 shows the side view of an inverted V-shaped groove. 
     FIG. 15 shows the side view of a funnel-shaped groove. 
     FIG. 16 shows the side view of a staircase-shaped groove. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 3 shows the basic structure of the present invention. A groove  26  is inscribed in an insulating substrate  25 . FIG. 4 shows the side view of FIG.  3 . The groove is lined with a metallic layer  21 , which wraps around one side of the substrate  25  to form a bottom contact  242  for surface mounting. A LED chip  20  is mounted on the bottom of the groove  26  to make contact to the bottom electrode of the chip  20 . The top electrode of the chip  20  is wire-bonded to a second metal plate  22 , which wraps around another edge of the substrate  25  to form another bottom contact  241  for surface mounting. FIG. 5 shows the bottom view of FIG.  3 . 
     FIG. 6 shows a second embodiment of the present invention for multiple chips in parallel connection. The two chips are aligned along the longitudinal direction of the groove and may emit same color light or different color lights. Two chips  201  and  202  are mounted in the groove similar to that described in FIG.  3 . The bottom electrodes are in contact with the metallic layer  21 , which wraps around a semicircular conduit in the substrate  25  to form a bottom contact  242  for surface mounting. The two top electrodes of chips  201  and  202  are wire-bonded to a common metal plate  22 , which wraps around another semicircular conduit in the substrate  25  to form another bottom contact  241  for surface mounting. FIG. 7 shows the bottom view of FIG. 6, where two bottom contacts are placed side-by-side at the bottom of the substrate  25  for surface mounting to a motherboard. 
     FIG. 8 shows a third embodiment of the present invention. The grooved structure is similar to that in FIG.  3 . The LED has two top electrodes. One of the top electrodes is wire-bonded by wire  236  to the metal plate  21  with extension to the bottom contact  242  for surface mounting to a motherboard. Another top electrode of chip  20  is wire-bonded by wire  235  to the metal plate  22  with wrap-around extension to the bottom contact  241  for surface mounting to a motherboard. 
     FIG. 9 shows a fourth embodiment of the present invention. Three LED chips  201 ,  202 ,  203  for different color light emission or same color light emission are mounted on the metal plate at the bottom of a groove. Each chip has a bottom electrode, which is in contact with the common metal plate  21  and wraps around to the bottom of the substrate to form a bottom contact for surface mounting to a motherboard. Th top electrodes of the chips  201 ,  202 ,  203  are wire-bonded respectively by wires  231 ,  232 ,  233  to separate metal plates  221 ,  222 ,  223 , which wrap around the substrate  25  to form bottom contacts for surface mounting to a motherboard. 
     FIG. 10 shows a fifth embodiment of the present invention. The three LED chips  201 ,  202 ,  203  for different color emission have respect top electrodes wire-bonded by wires  231 ,  232 ,  233  to a common metal plate  21 , which wraps around the substrate  25  to form a bottom contact  242  for surface mounting to a motherboard. The bottom electrodes of the chips  201 ,  202 ,  203  are in contact respectively with individual metal strips  221 ,  222 ,  223 , which wrap around the substrate  25  to form bottom contacts  241  for surface mounting to a motherboard. 
     FIG. 11 shows a sixth embodiment of the present invention. The three LED chips  201 ,  202 ,  203  all have bottom electrodes. The common electrodes are in contact with the metal plate  21  in the groove, which wraps around to the bottom of the substrate to form contact for surface mounting to a motherboard. The other bottom electrodes of the chips  201 ,  202 ,  203  are in contact respectively with individual metal strips  221 ,  222 ,  223 , which wrap around to the bottom of the substrate  25  to form contacts for surface mounting to a motherboard. 
     FIG. 12 shows a seventh embodiment of the present invention. The chips  204 ,  205 ,  206  are similar to the chips  201 ,  202 ,  203  in FIG.  9 . However, the metal strip  212  for connection to the top electrode of chip  206  and the metal strips  221 ,  222  for connection to the top electrodes of chips  204 ,  205  respectively rest on opposite shoulders of the groove. The bottom electrodes of the chips  204 ,  205 ,  206  are in contact with the common metal plate  211 , which wraps around the substrate to form a common bottom contact for surface mounting. The top electrode of the chips  204 ,  205  are wire-bonded to metal strips  221 ,  222  respectively, which wrap around to the bottom of the substrate  25  to form contacts  241  for surface mounting to a motherboard. The top electrode of the chip  206  is wire-bonded to a metal strip  212 , which wraps around the substrate  25  to form a bottom contact  242  for surface mounting to a motherboard. 
     FIG. 13 shows the cross-section of a V-shaped groove for the basic structure shown in FIG.  3 . 
     FIG. 14 shows the cross-section of an invented V-shaped groove for the basic structure shown in FIG.  3 . 
     FIG. 15 shows the cross-section of a funnel shaped groove for the basic structure shown in FIG.  3 . 
     FIG. 16 shows the cross-section of a staircase shaped groove for the basic structure shown in FIG.  3 . 
     While the preferred embodiments of the invention have been described, it will be apparent to those skilled in the art that various modifications may be made in the embodiments without departing from the spirit of the invention. Such modifications are all within the scope of this invention.