Abstract:
Provided is a light emitting diode (LED) package including a phosphor substrate; an LED chip mounted on the phosphor substrate; a circuit board mounted on the other region of the phosphor substrate excluding the region where the LED chip is mounted; an electrode connection portion for electrically connecting the LED chip and the circuit board; and a sealing member that covers the LED chip, the circuit board, and the phosphor substrate.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2007-0094376 filed with the Korean Intellectual Property Office on Sep. 17, 2007, the disclosure of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a light emitting diode (LED) package and a method of manufacturing the same, and more specifically, an LED package, which can minimize a deviation of the color coordinate and can be reduced in size, and a method of manufacturing the same. 
         [0004]    2. Description of the Related Art 
         [0005]    In general, LEDs generate minority carriers (electrons and holes) injected by using a p-n junction structure of semiconductor and then recombine them to emit light. That is, when a forward voltage is applied to a semiconductor of a specific element, electrons and holes are recombined through migration in a positive-negative junction. Then, energy level is dropped, thereby emitting light. 
         [0006]    Since the LEDs can irradiate high-efficiency light using a low voltage, the LEDs can be used in home appliances, remote controls, electric signs, displays, various automated equipments and the like. 
         [0007]    In particular, as information communication devices are reduced in size and are slimmed, various parts of the devices such as resistors, condensers, noise filters and the like are further reduced in size. Recently, the LEDs are produced in the form of surface mount devices (SMDs) to be directly mounted on a printed circuit board (PCB). 
         [0008]    LED packages manufactured in the form of SMD are divided into top-view type and side-view type LED packages, depending on the use thereof. 
         [0009]    Hereinafter, a conventional LED package will be described in detail with reference to  FIG. 1 . 
         [0010]      FIG. 1  is a cross-sectional view of a conventional LED package. 
         [0011]    Referring to  FIG. 1 , the conventional LED package includes a lead frame  50  composed of a pair of lead terminals, a package  10  formed of synthetic resin so as to house portions of the lead frame  50  therein, an LED chip  30  mounted on the lead frame  50  positioned inside the package  10 , an electrode connection portion  40  for electrically connecting the LED chip  30  and the lead frame  50 , and a molding material  20  which is filled in the package  10  so as to protect the LED chip  30  and the electrode connection portion  40 , the molding material including phosphor. 
         [0012]    Meanwhile, general standards for determining the characteristics of an LED chip are a color, luminance, an intensity range of luminance and so on. Such characteristics of the LED chip are primarily determined by a material of a compound semiconductor used in the LED chip, and are secondarily affected by the structure of a package for mounting the LED chip and a molding material including phosphor filled in the package. In particular, the phosphor of the molding material filled in such an LED package has a great effect upon luminance of the LED chip and luminance distribution. 
         [0013]    In the conventional LED package, a voluminous space for filling the molding material is constant. Therefore, an amount of coated phosphor can be constantly maintained so as to minimize a deviation of the color coordinate. As a result, it is possible to implement high luminance. 
         [0014]    Recently, as a demand for high luminance of a screen and reduction in thickness of an LCD panel increases, the reduction in size and thickness of an LED package is considered to be an urgent problem. 
         [0015]    In the above-described LED package, however, there is a limit in minimizing the height of the package for securing the space required for filling the molding material including phosphor. Therefore, there are difficulties in reducing the size and thickness of the LED package. 
         [0016]    That is, although the deviation of the color coordinate can be minimized, there are difficulties in reducing the size and thickness of the LED package. 
       SUMMARY OF THE INVENTION 
       [0017]    An advantage of the present invention is that it provides an LED package in which an LED chip is directly mounted on a phosphor substrate so as to minimize the thickness of the package for securing a molding material filling space. Therefore, a deviation of the color coordinate can be minimized, and simultaneously, the size and thickness thereof can be reduced. 
         [0018]    Another advantage of the invention is that it provides a method of manufacturing the LED package. 
         [0019]    Additional aspects and advantages of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the general inventive concept. 
         [0020]    According to an aspect of the invention, a light emitting diode (LED) package comprises a phosphor substrate; an LED chip mounted on the phosphor substrate; a circuit board mounted on the other region of the phosphor substrate excluding the region where the LED chip is mounted; an electrode connection portion for electrically connecting the LED chip and the circuit board; and a sealing member that covers the LED chip, the circuit board, and the phosphor substrate. 
         [0021]    Preferably, the phosphor substrate is a glass substrate having phosphor contained therein or a glass substrate coated with phosphor. 
         [0022]    Preferably, the electrode connection portion is formed of wire. 
         [0023]    Preferably, the sealing member is formed of at least one of transparent epoxy and silicon and contains a reflective material. 
         [0024]    Preferably, the circuit board is a ceramic substrate having one or more pairs of electrodes formed therein. 
         [0025]    According to another aspect of the invention, a method of manufacturing an LED package comprises the steps of: preparing a phosphor substrate; mounting a circuit board on the phosphor substrate; mounting an LED chip on the other region of the phosphor substrate excluding the region where the circuit board is mounted; electrically connecting the LED chip and the circuit board through an electrode connection portion; and forming a sealing member such that the LED chip, the circuit board, and the phosphor substrate are covered by the sealing member. 
         [0026]    Preferably, the phosphor substrate is a glass substrate having phosphor contained therein or a glass substrate coated with phosphor. 
         [0027]    Preferably, the electrode connection portion is formed of wire. 
         [0028]    Preferably, the sealing member is formed of at least one of transparent epoxy and silicon and contains a reflective material. 
         [0029]    Preferably, the circuit board is a ceramic substrate having one or more pairs of electrodes formed therein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    These and/or other aspects and advantages of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
           [0031]      FIG. 1  is a cross-sectional view of a conventional LED package; 
           [0032]      FIG. 2  is a cross-sectional view of an LED package according to an embodiment of the invention; and 
           [0033]      FIGS. 3A to 3E  are cross-sectional views sequentially showing a method of manufacturing an LED package according to an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0034]    Reference will now be made in detail to the embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below in order to explain the present general inventive concept by referring to the figures. In the drawings, the thicknesses of layers and regions are exaggerated for clarity. 
         [0035]    Structure of LED Package 
         [0036]    Referring to  FIG. 2 , the structure of an LED package according to an embodiment of the invention will be described in detail. 
         [0037]      FIG. 2  is a cross-sectional view of an LED package according to an embodiment of the invention. 
         [0038]    As shown in  FIG. 2 , the LED package  100  according to an embodiment of the invention includes a phosphor substrate  110 , an LED chip  120  mounted on one surface of the phosphor substrate  110 , and a circuit board  130  mounted on the other region of the phosphor substrate  110  excluding the region where the LED chip  120  is mounted. 
         [0039]    Preferably, the phosphor substrate  110  is formed of a glass substrate having phosphor contained therein or a glass substrate coated with phosphor. 
         [0040]    The circuit board  130  has one or more pairs of electrodes  130   a  formed therein. In this embodiment, the circuit board  130  is formed of a ceramic substrate, which can be changed depending on element characteristics and process conditions. 
         [0041]    Further, the LED chip  120  and each of the electrodes  130   a  of the circuit board  130  are electrically connected through an electrode connection portion  140 . 
         [0042]    In this embodiment, the electrode connection portion  140  for electrically connecting the LED chip  120  and the electrode  130   a  is formed of wire. 
         [0043]    On the phosphor substrate  110  having the LED chip  120  mounted thereon, a sealing member  150  is formed so as to cover the LED chip  120 , the phosphor substrate  110 , and the circuit board  130 . The sealing member  150  is formed of at least one of transparent epoxy and silicon. Further, the sealing member  150  contains a reflective material such as TiO 2  or the like so as to prevent light, emitted from the LED chip  120  mounted on the phosphor substrate  110 , from being absorbed or scattered into the sealing member  150 . 
         [0044]    Further, the sealing member  150  serves to radiate some of heat generated from the LED chip  120  to the outside. 
         [0045]    Method of Manufacturing LED Package 
         [0046]    Referring to  FIGS. 3A to 3E , a method of manufacturing an LED package according to an embodiment of the invention will be described in detail. 
         [0047]      FIGS. 3A to 3E  are cross-sectional views sequentially showing a method of manufacturing an LED package according to an embodiment of the invention. 
         [0048]    First, as shown in  FIG. 3A , a phosphor substrate  110  is mounted on a substrate fixing device  200 . 
         [0049]    In this case, the phosphor substrate  110  according to the invention is formed of a glass substrate, which is formed by a hot press using a mixture of glass powder and phosphor powder, or a glass substrate having one surface coated with phosphor through spray coating. 
         [0050]    In the case of the phosphor substrate  110  formed of a glass substrate having one surface coated with phosphor through the spray coating, the phosphor coating process can be performed separately from a main process for mounting an LED chip, which will be described below. Therefore, regardless of the main process, the phosphor coating process can be performed so that the thickness precision of the phosphor increases. 
         [0051]    That is, an amount of phosphor can be maintained constantly through the phosphor substrate  110 . Accordingly, a deviation of the color coordinate can be minimized, and a separate operation for adjusting the color coordinate is not necessary. Therefore, it is possible to enhance a manufacturing yield of LED packages. 
         [0052]    Then, as shown in  FIG. 3B , one or more circuit boards  130  are mounted on one surface of the phosphor substrate  110 . 
         [0053]    The circuit boards  130  are fixed to the phosphor substrate  100  through an adhesive and may be formed of ceramic having a pair of electrodes  130   a.    
         [0054]    Subsequently, as shown in  FIG. 3C , one or more LED chips  120  are mounted on the other regions of the phosphor substrate  110  excluding the regions where the circuit boards  130  are mounted. 
         [0055]    Then, the LED chips  120  and the electrodes  130   a  of the circuit boards  130  are electrically connected to each other through electrode connection portions  140  formed of wire. 
         [0056]    Next, as shown in  FIG. 3D , a dam  300  for defining a sealing member filling space is formed on a portion of the upper surface of the circuit board  130  adjacent to either side wall of the substrate fixing device  200 . 
         [0057]    Then, with the dam  300  being set to a barrier, the sealing member  150  is filled into the space defined on the phosphor substrate  110  having the LED chips  120  mounted thereon such that the LED chips  120 , the phosphor substrate  110 , and the circuit boards  130  are all covered by the sealing member  150 . 
         [0058]    The sealing member  150  may be formed of at least one of transparent epoxy and silicon. Preferably, the sealing member  150  contains a reflective material such as TiO 2  or the like so as to prevent light, emitted from the LED chips  120  mounted on the phosphor substrate  110 , from being absorbed or scattered into the sealing member  150 . 
         [0059]    Further, the sealing member  150  serves to radiate some of heat generated from the LED chip  120  to the outside. 
         [0060]    Although a few embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the appended claims and their equivalents.