Abstract:
A light emitting diode package is provided including: a lead frame that includes an electrode pad and an electrode lead that are integrally formed to each other; and a housing, wherein the electrode pad is exposed in a first direction through a window formed by inner walls of the housing, and the electrode lead is exposed in a second direction through a through-hole, wherein the housing includes a step jaw prepared by sinking the housing inner walls.

Description:
PRIORITY 
     This application claims priority from and the benefit of Korean Patent Application No. 10-2008-0055242, filed on Jun. 12, 2008, which is hereby incorporated by reference for all purposes as if fully set forth herein. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Disclosed exemplary embodiment is directed to a semiconductor device, and more specifically to a light emitting diode (“LED”) package. 
     2. Description of the Related Art 
     In general, light emitting diodes (“LEDs”) are electrical components that emit light when carriers (electrons or holes) injected into a P-N junction structure of a semiconductor are recombined. 
     When a forward voltage is applied across the semiconductor of P-N junction structure, electrons and holes move beyond the junction surface to be recombined to each other. As a consequence, energy becomes lower than when the electrons and holes are existent independently from each other, and light is emitted as much as the energy gap. LEDs may emit high efficiency light with a low voltage and therefore the LEDs are recently used for electric appliances, remote controllers, electrical signage, displaying devices, various automatic appliances, etc. 
     In the meanwhile, the LEDs are manufactured as surface mount device (“SMD”) types of LED packages according to devices for information telecommunications being slimmer or smaller. The SMD-type LED packages may be classified into top view types and side view types depending on their use. The side view-type LED packages have been mainly used for backlight units for liquid crystal displays that are employed in cell phones. 
     The conventional side view-type LED packages have been produced by injection molding. A side view-type LED package includes slopped surfaces, including an upper surface, a lower surface, a left surface, and a right surface, to allow a housing to be easily released from the mold after the injection molding. These slopped surfaces may cause the LED package to be tilted when the LED package is mounted on a printed circuit board (“PCB”). Furthermore, mold resin may overflow the window which exposes the LED chip and spread to other portions when being filled in the window. 
     Therefore, there is a need of providing an LED package that includes a horizontal support portion on the bottom surface of the housing, which prevents tilting of the LED package due to the slopped surfaces. 
     In addition, there is a need of providing an LED package that includes a single step indentation at a corner of the housing along the edge of the window so that the mold resin does not overflow the window when being filled in the window. 
     SUMMARY OF THE INVENTION 
     According to an exemplary embodiment, there is provided a light emitting diode package including: a lead frame that includes an electrode pad and an electrode lead that are integrally formed to each other; and a housing, wherein the electrode pad is exposed in a first direction through a window formed by inner walls of the housing, and the electrode lead is exposed in a second direction through a through-hole, wherein the housing includes a single step indentation at a corner of the housing along the edge of the window. 
     The electrode lead may be bent near the through-hole in the first direction, and then bent in the opposite direction of the second direction, and an end of the electrode lead may be extended in the opposite direction of the first direction. 
     The housing may include an inclined surface which allows a clearance to be provided when the electrode lead is bent in the first direction. 
     The housing may include a receiving space that receives the end of the electrode lead when the electrode lead is bent in the opposite direction of the second direction. 
     The housing may include a plurality of slopped surfaces that are slopped from the lead frame in the opposite direction of the first direction, wherein the slopped surface provided near the bottom surface of the housing includes a horizontal support surface that is parallel to the end of the electrode lead. 
     The lead frame may include first and second lead frames, and a light emitting diode is mounted on an electrode pad of one of the first and second lead frames. 
     As described above, the LED package according to the exemplary embodiment has a horizontal support portion on the bottom surface of the housing, such that tilting of the LED package due to the slopped surfaces may be prevented when the LED package is mounted on the PCB nonetheless the existence of the slopped surfaces which helps the housing is easily released from the mold. 
     And, the LED package according to the exemplary embodiment has the single step indentation at the corner of the housing along the circumference of the window, such that the mold resin may be prevented from overflowing the window when being filled in, thus allowing the amount of the resin to be uniform upon. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features of the present disclosure will be described in reference to certain exemplary embodiments thereof with reference to the attached drawings in which: 
         FIG. 1  is a perspective view illustrating a light emitting diode package according to an exemplary embodiment; 
         FIG. 2  is another perspective view of the light emitting diode package shown in  FIG. 1 ; and 
         FIG. 3  is a side view of the light emitting diode package shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present disclosure by referring to the figures. 
       FIG. 1  is a perspective view illustrating an LED package according to an exemplary embodiment. Referring to  FIG. 1 , the LED package according to the exemplary embodiment includes a housing  100  and a lead frame  200 . 
     The housing  100  includes a window  104  exposing electrode pads  212  and  222  and through-holes  122  exposing electrode leads  214  and  224  to the exterior. The window  104  may be formed by a housing wall  110  that is composed of upper and lower wall  114  and  112  and left and right wall  116  and  118 . The through-hole  122  may be located at a side surface of the housing  100 . The housing  100  may be produced by injection-molding plastics. 
     The window  104  may by symmetrically formed with respect to each of the vertical axis and horizontal axis. The outer surface of the lower wall  112 , which is a lower part of the housing  100  with respect of the horizontal axis, configures a horizontal support surface  113 . The horizontal support surface  113  supports the LED package such that it is capable of being mounted on a PCB while maintaining a horizontal orientation. 
     The housing  100  has a single step indentation  120  at a lower corner of the housing  100  along the edge of the window  104  in the direction of electrode pads  212  and  222 . For example, housing  100  has a single step indentation  120  prepared by indenting the corner of the inner wall  106  of the lower wall  112  of the housing  100 . The single step indentation  120  prevents the mold resin from overflowing the window  104  when the mold resin is filled in the window  104 , such that the amount of the resin may be uniformly adjusted upon a work of filling the mold resin in the window  104 . Even though this exemplary embodiment was described such that the single step indentation  120  is provided on the inner wall  106  of the lower wall  112  in the housing wall  110 , the exemplary embodiment is not limited thereto. For example, the single step indentation  120  may be provided on other walls in the housing wall  110 , such as the inner wall  106  of one or more of the upper wall  114 , the left wall  116 , and the right wall  118 . 
     The inner wall  106  of the housing wall  110  may be inclined at a predetermined angle. This structure causes the window  104  to be shaped as a trumpet, such that the window  104  has a gradually increasing width and length as going toward its front side. This trumpet-shaped structure may increase the optical efficiency. 
     The left and right side walls  116  and  118 , which are symmetric with respect to the vertical axis, are cut off at their outer corners, thus the front portion of the lateral sides forms inwardly-inclined surfaces S 1 . The inwardly-inclined surface S 1  provides a clearance for the electrode lead  214  and  224 , which passes through the through-hole  122  and is bent in the front direction, and this may provide a good bending characteristic to the electrode lead  214  and  224 . 
     In the meanwhile, the housing  100  is formed to be slopped rearwards with respect to the electrode pads  212  and  222 . Reference numerals  132 ,  134 , and  135  represent the surfaces slopped rearwards. This slopped structure of the housing  100  allows the housing  100  to be easily released from the injection mold after being injection-molded. 
     The lead frame  200  includes a first lead frame  210  and a second lead frame  220 . The first lead frame  210  includes a conductive, metal-based electrode pad  212  and an electrode lead  214  that are integrally formed with each other and the lead frame  220  includes a conductive, metal-based electrode pad  222  and an electrode lead  224  that are integrally formed with each other. The conductive metal may be copper coated with silver. The electrode pads  212  and  222  are arranged to be insulated from each other in the housing  100 , and exposed through the window  104 . 
     An LED chip (not shown) may be mounted on the electrode pad  222  of the second lead frame  220 . The electrode pad  222  of the second lead frame  220  is electrically connected to the LED chip directly or via a bonding wire. The electrode pad  212  of the first lead frame  210  may be electrically connected to the LED chip via a bonding wire. 
     The electrode leads  214  and  224  are externally exposed through the through-hole  122 . The electrode leads  214  and  224  are electrically connected to electrode terminals of the PCB (not shown) when the LED package is mounted on the PCB (not shown). The electrode leads  214  and  224  externally exposed may be bent in a predetermined direction to have a predetermined shape. 
     This will be described in further detail with respect to the second lead frame represented in a disassembled state outside the housing  100 , as shown in  FIG. 1 . The electrode lead  224  is extended through the through-hole  122  located at a lateral side of the housing  100 , and bent near the through-hole  122  in the front direction, then bent in the laterally-inward direction beneath the housing  100 , then the end of the electrode lead  224  extends in the rearward direction. 
       FIG. 2  is another perspective view of the LED package shown in  FIG. 1 . Referring to  FIG. 2 , receiving spaces are provided at the bottom surface of the housing  100  in the LED package, which are formed by indenting the bottom surface of both ends of the housing  100 . Surfaces represented by reference numerals  123 ,  124 ,  136 , and  137  form the receiving spaces in the housing  100 . The receiving spaces receive the electrode leads  214  and  224  that are exposed through the through-hole  122  and bent. The bottom surface of the electrode leads  214  and  224  received in the receiving space may be coplanar with the horizontal support surface  113 . 
     In the meanwhile, the outer surface of the housing  100  is configured to be slopped rearwards with respect to the electrode pads  212  and  222 . Reference numerals  133 ,  134 ,  135 ,  136 ,  137 ,  138 , and  139  refer to the surfaces slopped rearwards. It can be seen from the slopped surfaces of the housing  100  illustrated in  FIG. 1  that the housing  100  is slopingly formed to be symmetric with respect to the upper and lower axis and left and right axis. This slopped structure allows the housing  100  to be easily released from the injection mold after being injection-molded. 
     In the meanwhile, the housing  100  according to the exemplary embodiment has a horizontal support portion  140  on its bottom surface, which is parallel with the horizontal support surface  113 . The horizontal support portion  140  provided near the slopped surface  113  has a thickness T which increases as the horizontal support portion  140  goes rearwards. Moreover, the horizontal support portion  140  has a width which decreases as the horizontal support portion  140  goes rearwards (W 2 &lt;W 1 ). 
     The conventional LED package has a problem of being tilted due to the slopped surface  133  provided at the bottom surface of the housing when being mounted on the PCB. However, such a problem may be solved in the exemplary embodiment since the horizontal support portion  140  is horizontally extended from the horizontal support surface  113  and formed on the slopped surface  133  to be able to horizontally support the LED package.  FIG. 3  is a side view of the LED package shown in  FIG. 1 , and it can be seen in  FIG. 3  that the horizontal support portion  140  may prevent a rearward tilting of the LED package due to the slopped surface  133 . 
     Reference numeral “ 214 ” refers to the electrode lead, reference numeral “ 142 ” to a portion formed at the top surface of the housing  100  correspondingly to the horizontal support portion  140 , and reference numeral  132  to the slopped surface formed at the top surface of the housing  100  correspondingly to the slopped surface  133 . 
     Although the present disclosure has been described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that a variety of modifications and variations may be made to the present disclosure without departing from the spirit or scope of the present disclosure defined in the appended claims, and their equivalents.