Abstract:
Disclosed is a light-emitting diode package. The light-emitting diode package includes an electrode pad on which a chip is placed; a housing having a window through which the chip is exposed; a housing wall defining the window; and an electrode lead extended from the electrode pad in a direction of the housing to be exposed outside a surface of the housing, wherein the housing wall formed in the direction comprises a first portion and a second portion thicker than the first portion to cover the electrode lead.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority from and the benefit of Korean Patent Application No. 10-2008-0008489, filed on Jan. 28, 2008, which is hereby incorporated by reference for all purposes as if fully set forth herein. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to a semiconductor device, and more particularly, to a light-emitting diode (LED) package. 
         [0004]    2. Description of the Related Art 
         [0005]    A light-emitting diode, usually called an “LED,” is a semiconductor diode that emits incoherent narrow-spectrum light when electrically biased in the forward direction of the p-n junction. This effect is a form of electroluminescence. 
         [0006]    LEDs are often used as small indicator lights on electronic devices and increasingly in higher power applications such as flashlights and area lighting. 
         [0007]    These LEDs are commonly used in the form of a package together with some other components. LED packages can be classified into top view types and side view types according to their use. The latter are usually used as backlights for small mobile devices, such as cellular phones. 
         [0008]    A recent LED package tends to be manufactured in the type of a surface mount device (SMD) that permits the LED package to be very small in size to keep pace with slim and compact designed devices on which to be mounted. A SMD type of LED package includes a housing configuring its appearance, at least one electrode pad, and at least one electrode lead extended from the electrode pad to be exposed outside the housing and bent in a direction of the housing. Such bending of the electrode lead may leave a clearance between the electrode pad and a portion of the housing where the electrode pad meets. 
       SUMMARY OF THE INVENTION 
       [0009]    Accordingly, the present invention has been designed to solve the aforementioned problem and an aspect of the present invention provides a light-emitting diode package with a high reliability and an excellent light efficiency. 
         [0010]    Additional features of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. 
         [0011]    An exemplary embodiment of the present invention provides a light-emitting diode package including: an electrode pad on which a chip is placed; a housing having a window through which the chip is exposed; a housing wall defining the window; and an electrode lead extended from the electrode pad in a direction of the housing to be exposed outside a surface of the housing, wherein the housing wall formed in the direction includes a first portion and a second portion thicker than the first portion to cover the electrode lead. 
         [0012]    The electrode lead may be provided in plurality, and the second portion may be provided in the number corresponding to the number of the electrode leads. 
         [0013]    An inclined angle between an inner surface of the first portion and the electrode pad may be larger than an inclined angle between an inner surface of the second portion and the electrode pad. 
         [0014]    The electrode lead may be bent in a first direction of the housing. 
         [0015]    The first direction of the housing may be a rear direction thereof. 
         [0016]    The electrode lead may be further bent in a second direction of the housing. 
         [0017]    A bottom surface of the housing may include a first bottom surface, and a second bottom surface having a first recessed space in a top direction of the housing so that the electrode lead is arranged in the first recessed space. 
         [0018]    The electrode lead may be arranged on the bottom surface of the housing and a side surface of the housing. The side surface of the housing may include a first side surface, and a second side surface having a second recessed space in a side direction of the housing so that the electrode lead is arranged in the second recessed space. 
         [0019]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    The above and other features of the present invention will be described in reference to certain exemplary embodiments thereof with reference to the attached drawings in which: 
           [0021]      FIG. 1  is a perspective view illustrating an LED package according to an exemplary embodiment of the present invention; 
           [0022]      FIG. 2  is a front view of the LED package shown in  FIG. 1 ; 
           [0023]      FIG. 3A  is a top view illustrating the housing of an LED package according to an exemplary embodiment of the present invention,  FIG. 3B  is a rear view of the housing shown in  FIG. 3A , and  FIG. 3C  is a side view of the housing shown in  FIG. 3A ; 
           [0024]      FIG. 4  is a cross sectional view of the LED package taken along the line I-I′ of the  FIG. 2 ; and 
           [0025]      FIG. 5  is a rear view of the LED package shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    Reference will now be made in detail to embodiments of the present invention, 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 invention by referring to the figures. 
         [0027]    Throughout the specification, the term “front side” refers to a part of an LED package where a light-emitting surface will be formed, the term “rear side” an opposite side of the front side, and the term “bottom side” a portion of the LED package which is seated on a device to which the LED package will be applied, the term “top side” an opposite side of the bottom side, the term “left side” a left portion of the LED package and “right side” a right portion thereof as seen from the front side. 
         [0028]    And, the term “front direction” or “direction of front side”, “rear direction” or “direction of rear side”, “left direction” or “direction of left side”, “right direction” or “direction of right side”, “top direction” or “direction of top side”, and “bottom direction” or “direction of bottom side”, respectively, refer to a direction which the front side, the rear side, the left side, the right side, the top side, and the bottom side look toward, respectively. 
         [0029]    Hereinafter, exemplary embodiments of the present invention will be described in more detail with reference to accompanying drawings. 
         [0030]      FIG. 1  is a perspective view illustrating an LED package  100  according to an exemplary embodiment of the present invention. 
         [0031]    Referring to  FIG. 1 , LED package  100  includes a housing  110 , an electrode pad  130 , and an electrode lead  140 . Housing  110  includes a front portion and a rear portion. The front portion includes a housing wall formed in top, bottom, left, and right directions. A window  120  is defined by housing wall. Electrode pad  130  is provided between the front portion and the rear portion, more specifically, one side of the electrode pad  130  contacting the bottom surface of the front portion, and the other side contacting the top surface of the rear portion. Electrode lead  140  is extended from electrode pad  130  to be exposed outside the housing  110 . Electrode pad  130  may include a first electrode pad  132  and a second electrode pad  134 . An LED chip (not shown) is seated on first electrode pad  132 , with its positive electrode connected to first electrode pad  132  directly or via a bonding wire (not shown), its negative electrode to second electrode pad  134  via a bonding wire (not shown), and vice versa. 
         [0032]    The LED chip and parts of first and second electrode pads  132  and  134  may be externally exposed through window  120 . 
         [0033]    Transparent resin or other resin that passes specific-spectrum light alone may be filled in window  120 . 
         [0034]    The resin may contain a phosphor absorbing a certain wavelength of light and emitting another wavelength of light. 
         [0035]    LED package  100  may be mounted on a printed circuit board (not shown) of a device (not shown). Electrode lead  140  may be exposed externally from a bottom side of housing  110 , extended in the rear direction of LED package  100 , and bent subsequently in the left or right direction and in the top direction in such a manner to wrap around an edge portion of the rear portion of housing  110 . 
         [0036]    The rear portion of housing  110  may be partially recessed to provide spaces in which electrode lead  140  may be accommodated and completely hidden by housing  110  as seen from the front side. Depending on manufacturing processes of LED package  100  or structures of a device on which to be mounted, electrode lead  140  may be formed to protrude slightly beyond the outline of the front portion of LED package  100  as seen from the front side of LED package  100 . 
         [0037]    Housing  110  may have a hole formed around where electrode lead  140  has been bent. 
         [0038]      FIG. 2  is a front view of the LED package shown in  FIG. 1 . 
         [0039]    Referring to  FIG. 2 , window  120  is shown, which is defined by housing wall  112 . Light generated from an LED chip (not shown) would be externally emitted through window  120 . Lead electrode  130  connected to the LED chip is exposed through window  120 . Housing wall  112  may be divided into an upper wall, a lower wall, a left wall, and a right wall. The lower wall may include a first portion  114  with a first thickness T 1  and two second portions  116  located at both ends of first portion  114 , each with a second thickness T 2  larger than the first thickness T 1 . 
         [0040]    As described above with reference to  FIG. 1 , LED package  100  may include a plurality of lead electrodes  140  (two in  FIG. 1 ) that are extended externally from electrode pad  130  to be exposed outside housing  110 . Lead electrodes  140  may be extended parallel with each other. 
         [0041]    Lead electrode  140  may be extended through a portion of housing  110  located adjacent to second portion  116 . Lead electrode  140  is hidden under second portion  116  not to be seen from the front side of LED package  100 . Making second portion  116  thicker than first portion  114  may increase the area of the top surface of lead electrode  140  which abuts the bottom surface of the front portion of housing  110 . 
         [0042]    An inner wall of the front portion inclined at a prescribed angle to reflect light generated by the LED chip (not shown) may effect the improvement in light efficiency of beams emitted from LED package  100 . The lower wall, more specifically first portion  114 , of LED package  100  includes a first inner wall  114   s  and the upper wall includes a second inner wall  118   s  opposite to first inner wall  114   s . First inner wall  114   s  may be symmetrical to a part of second inner wall  118   s.    
         [0043]      FIG. 3A  is a top view illustrating the housing of an LED package according to an exemplary embodiment of the present invention,  FIG. 3B  is a rear view of the housing shown in  FIG. 3A , and  FIG. 3C  is a side view of the housing shown in  FIG. 3A . 
         [0044]    Referring to  FIGS. 3A to 3C , a bottom surface of housing  110  may include a first bottom surface  112   a , which is the bottom surface of the front portion, and a second bottom surface  152   a , which is the bottom surface of the rear portion. Second bottom surface  152   a  is recessed in the top direction of LED package  100  so that the rear portion of housing  110  has a first space  160  as shown in  FIG. 3   b.    
         [0045]    A left surface or a right surface of housing  100  may include a first side surface  112   b , which is the side surface of the front portion, and a second side surface  152   b , which is the side surface of the rear portion. Second side surface  152   b  is recessed in the left or right direction of LED package  100  so that the rear portion of housing  110  has a second space  162  as shown in  FIG. 3A . Accordingly, a distance between two first side surfaces  112   b  is larger than a distance between two second side surfaces  152   b.    
         [0046]    A supporting surface  154  may be formed between two first spaces  160 . 
         [0047]    Although not shown, electrode lead  140  may be extended from electrode pad  130  outside housing  110  and bent in the rear direction, in the left or right direction, and then in the top direction, so that the extended electrode lead  140  may be arranged in spaces  160  and  162  not to be seen from the front side of LED package  100 . 
         [0048]      FIG. 4  is a cross sectional view of the LED package taken along the line I-I′ of the  FIG. 2 , and  FIG. 5  is a rear view of the LED package shown in  FIG. 1 . 
         [0049]    Referring to  FIGS. 4 and 5 , thickness T 2  of second portion  116  is thicker than that T 1  of the upper wall of housing wall  112  opposite to second portion  116 . A thickness of first portion  114  may be equal/different to/from thickness T 1 . However, thickness T 2  of second portion  116  is thicker than that of first portion  114 . 
         [0050]    Also, an angle θ 1  between an inner surface  116   s  of second portion  116  and electrode pad  134  may be smaller than an angle θ 2  between an inner surface  118   s  of the upper wall and electrode pad  134 . 
         [0051]    Electrode lead  140  is extended from electrode pad  134  to be exposed outside housing  110  and bent around its first bent portion  140   a  in the rear direction of LED package  100  to be arranged in first space  160 . And, electrode lead  140  is further bent around a second bent portion  140   b  to be arranged in second space  162 . 
         [0052]    As described above, making second portion  116  thicker than other portions of housing wall  112  may increase the area of the top surface of lead electrode  140  which abuts the bottom surface of the front portion of housing  110 , and this may prevent the occurrence of a clearance therebetween. 
         [0053]    Although the present invention 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 invention without departing from the spirit or scope of the present invention defined in the appended claims, and their equivalents.