Abstract:
A method of protecting an LED chip from damage by ESD and EMI when the LED chip is housed in a light-emitting diode(s) housing package (LED package) and the LED package is mounted on a printed circuit board is provided. The method comprises a step of not including an ESD and EMI suppressing Zener diode within the combination of the printed circuit board and the LED package and of providing within the combination of the printed circuit board and the LED package a first conductive member and a spaced apart second conductive member which are electrically connected to the LED chip and which have defined between them at least one insulative ESD and/or EMI suppressing region which breaks down in its insulative properties when subjected to voltages of absolute magnitudes greater than a predetermined threshold voltage.

Description:
[0001]    This application claims priority from Korean Patent Application No. 10-2013-0139144 filed on Nov. 15, 2013 in the Korean Intellectual Property Office, the disclosure of which application is incorporated herein by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Field of Disclosure 
         [0003]    The present disclosure of invention relates to a light source unit and a backlight assembly having the same. 
         [0004]    2. Description of Related Technology 
         [0005]    Liquid crystal displays (LCDs) are some of the most widely used types of flat or otherwise thin panel displays (FPDs). Generally, an LCD includes two substrates having electrodes and a liquid crystal layer interposed between the substrates. In an LCD, voltages are applied to the electrodes to thereby rearrange liquid crystal molecules of a liquid crystal layer, thereby controlling an amount of light that passes through the liquid crystal layer and one or more polarizers. 
         [0006]    Being a passive light-emitting type of device, the typical transmissive type LCD requires a backlight assembly which provides light that is to pass through the liquid crystal layer. Examples of light sources that may be used in the backlight assembly may include a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), and a light-emitting diode (LED). Currently, there is a growing demand for backlight assemblies using high-luminance LEDs. 
         [0007]    Individual LED&#39;s can be provided as integrated within an LED package. Such LED packages may be arranged on a circuit board and used as light sources for a corresponding LCD. 
         [0008]    An LED package typically includes a Zener diode that is connected within the package so as to protect the internal LED&#39;s from electrostatic discharge (ESD) and electromagnetic interference (EMI). The Zener diode is typically connected in parallel to the LED&#39;s and protects the LED&#39;s from unexpected ESD and/or EMI. 
         [0009]    However, if such a Zener diode is integrally included in each LED package, the size of each LED package inevitably increases. In addition, the increased size of the LED packages leads to an increase in the size of the backlight assembly and of the display device which includes the Zener-including LED packages. Furthermore, since the process of mounting the Zener diode is added to the manufacture of each package, the number of processes and cost required to manufacture all the LED packages used within the LCD increases and the cost of the LCD increases. 
         [0010]    It is to be understood that this background of the technology section is intended to provide useful background for understanding the here disclosed technology and as such, the technology background section may include ideas, concepts or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to corresponding invention dates of subject matter disclosed herein. 
       SUMMARY 
       [0011]    Aspects of the present disclosure of invention include a method of protecting an LED chip from damage by ESD (electrostatic discharge) and EMI (electromagnetic interference) when the LED chip is housed in a light-emitting diode(s) housing package (LED package) and the LED package is mounted on a printed circuit board. The method comprises a step of not including an ESD and EMI suppressing Zener diode within the combination of the printed circuit board and the LED package and of providing within the combination of the printed circuit board and the LED package a first conductive member and a spaced apart second conductive member which are electrically connected to the LED chip and which have defined between them at least one insulative ESD and/or EMI suppressing region which breaks down in its insulative properties when subjected to voltages of absolute magnitudes greater than a predetermined threshold voltage. 
         [0012]    However, aspects of the present disclosure of invention are not restricted to the specific ones set forth herein. The above and other aspects of the present disclosure will become more apparent to one of ordinary skill in the art to which the present disclosure of invention pertains by referencing the detailed description given below. 
         [0013]    According to an aspect of the present disclosure, there is provided a light source unit comprising a light-emitting diode(s) housing package (LED package) which comprise an LED chip, and a circuit board on which the LED package is mounted, wherein the circuit board comprises a first conductive member and a spaced apart second conductive member which are electrically connected to the LED chip, wherein the first conductive member is located on a side of the LED package, the second conductive member is located on the other side of the LED package which is opposite the side of the LED package, and the first conductive member comprises a first protrusion which protrudes toward the second conductive member. 
         [0014]    A minimum distance between the first protrusion and the second conductive member may be smaller than a minimum distance between the first conductive member and the second conductive member in a portion where the first protrusion is not formed. 
         [0015]    The second conductive member may comprise a second protrusion which protrudes toward the first conductive member 
         [0016]    The first protrusion and the second protrusion may face each other. 
         [0017]    The first protrusion and the second protrusion may be symmetrical to each other with respect to a virtual line that halves an area between the first conductive member and the second conductive member. 
         [0018]    The first protrusion and the second protrusion may be arranged alternately. 
         [0019]    Each of the first protrusion and the second protrusion may be bent at least once, wherein bent portions of the first protrusion may be located between portions of the second conductive member, and bent portions of the second protrusion may be located between portions of the first conductive member. 
         [0020]    Each of the first protrusion and the second protrusion may be bent multiple times in a clockwise direction or a counterclockwise direction to be electrically connected to the LED chip. 
         [0021]    According to another aspect of the present disclosure of invention, there is provided a light source unit comprising an LED package, and a circuit board on which the LED package is mounted, wherein the LED package comprises an LED chip, and a first lead frame and a second lead frame which are electrically connected to the LED chip, wherein the first lead frame comprises a first protrusion which protrudes toward the second lead frame. 
         [0022]    A minimum distance between the first protrusion and the second lead frame may be smaller than a minimum distance between the first lead frame and the second lead frame in a portion where the first protrusion is not formed. 
         [0023]    The second lead frame may comprise a second protrusion which protrudes toward the first lead frame. 
         [0024]    The first protrusion and the second protrusion may face each other. 
         [0025]    The first protrusion and the second protrusion may be symmetrical to each other with respect to a virtual line that halves an area between the first lead frame and the second lead frame. 
         [0026]    The light source unit may further comprise a housing which fixes the LED chip, the first lead frame, and the second lead frame. 
         [0027]    According to still another aspect of the present disclosure of invention, there is provided a backlight assembly comprising a light source unit comprising an LED package which comprises an LED chip and a circuit board on which the LED package is mounted, and an accommodating housing which houses the light source unit, wherein the circuit board comprises a first conductive member and a second conductive member which are electrically connected to the LED chip, wherein the first conductive member is located on a side of the LED package, the second conductive member is located on the other side of the LED package which is opposite the side of the LED package, and the first conductive member comprises a first protrusion which protrudes toward the second conductive member. 
         [0028]    A minimum distance between the first protrusion and the second conductive member may be smaller than a minimum distance between the first conductive member and the second conductive member in a portion where the first protrusion is not formed. 
         [0029]    The second conductive member may comprise a second protrusion which protrudes toward the first conductive member. 
         [0030]    The first protrusion and the second protrusion may face each other. 
         [0031]    The backlight assembly may further comprise a light guide plate (LGP) which is placed to face the LED package and guides light emitted from the LED chip such that the light can exit the LGP through an exit surface. 
         [0032]    The backlight assembly may further comprise a diffusion sheet which is disposed on the exit surface of the LGP and diffuses light emerging from the exit surface of the LGP, and a reflective sheet which is disposed between the LGP and the accommodating housing and reflects light leaked from the LGP back to the LGP. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]    The above and other aspects and features of the present disclosure of invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which: 
           [0034]      FIG. 1  is a plan view of a light source unit according to an embodiment of the present disclosure; 
           [0035]      FIG. 2  is an enlarged view of a portion II of  FIG. 1 ; 
           [0036]      FIG. 3  is a cross-sectional view taken along the line III-III′ of  FIG. 2 ; 
           [0037]      FIG. 4  is an enlarged view of a portion IV of  FIG. 2 ; 
           [0038]      FIG. 5  is an equivalent circuit diagram of a portion of the light source unit of  FIG. 1 ; 
           [0039]      FIGS. 6 through 9  are partial enlarged views of light source units according to other embodiments of the present disclosure; 
           [0040]      FIG. 10  is a partial enlarged view of a light source unit according to another embodiment in accordance with the present disclosure of invention; 
           [0041]      FIG. 11  is an equivalent circuit diagram of a portion of the light source unit shown in  FIG. 10 ; 
           [0042]      FIG. 12  is a partial enlarged view of a light source unit according to another embodiment of the present disclosure; 
           [0043]      FIG. 13  is a partial enlarged view of a light source unit according to another embodiment of the present disclosure; 
           [0044]      FIG. 14  is a cross-sectional view taken along the line XIV-XIV′ of  FIG. 13 ; and 
           [0045]      FIG. 15  is an exploded cross-sectional view of a backlight assembly according to an embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0046]    The aspects and features of the present disclosure of invention and methods for achieving the aspects and features will be apparent by referring to the embodiments to be described in detail with reference to the accompanying drawings. However, the present teachings are not limited to the embodiments disclosed hereinafter, but can be implemented in diverse forms based on the teachings. The matters defined in the description, such as the detailed construction and elements, are merely specific and nonlimiting details provided to assist those of ordinary skill in the art in a comprehensive understanding of the present disclosure of invention. 
         [0047]    The term “on” that is used to designate that an element is on another element or located on a different layer or a layer includes both a case where an element is located directly on another element or a layer and a case where an element is located on another element via another layer or still another element. In the entire description, the same drawing reference numerals are used for same or alike elements across various figures. 
         [0048]    Although the terms “first, second, and so forth” are used to describe diverse constituent elements, such constituent elements are not limited by the terms. The terms are used only to discriminate a constituent element from other constituent elements. Accordingly, in the following description, a first constituent element may be a second constituent element. 
         [0049]    Hereinafter, embodiments of the present disclosure will be described with reference to the attached drawings. 
         [0050]      FIG. 1  is a plan view of a light source unit according to a first embodiment of the present disclosure. Referring to  FIG. 1 , the light source unit according to the current embodiment includes a printed circuit board  100  and a light-emitting diode(s) (LED) package  200 . 
         [0051]    The circuit board  100  may includes a support plate (substrate)  110 , a connector  120 , and a pattern of conductive members  130 . 
         [0052]    The support plate  110  may support the connector  120  and the conductive members  130 . The support plate  110  may be shaped like a rectangle extending in a direction. The support plate  110  may be formed of a rigid member such as a glass substrate. However, the present disclosure is not limited thereto, and the support plate (substrate)  110  may also or instead be formed of a flexible insulative member such as a polyimide substrate. In addition to a base insulator, the support plate  110  may include an insulation enhancing material. Here, the insulation enhancing material may include, but is not limited to, one or more of a silicon nitride, a silicon oxide and a silicon oxynitride (SiOxNy). 
         [0053]    The connector  120  may be located on an end of the support plate  110 . The connector  120  may be a connection terminal used to apply an external voltage to the LED package(s)  200  which will be described later. The connector  120  may include a first pin  120   a  to which an external driving voltage is applied and a second pin  120   b  to which an external ground voltage is applied. 
         [0054]    The patterned conductive members  130  may be located on a surface of the support plate  110  on which the connector  120  is disposed. The conductive members  130  may be formed of a conductive material, for example, a metal such as copper or silver. 
         [0055]    The conductive members  130  may be provided as a plurality of different conductive materials for example provided as a laminated stack of conductive layers. The conductive members  130  may be separated from each other. Two of the conductive members  130  may be connected respectively to the first pin  120   a  and the second pin  120   b  so as to receive external voltages. The conductive members  130  not connected to the first pin  120   a  and the second pin  120   b  may be separated from each other and arranged in a line. 
         [0056]    The LED package  200  may be mounted on the circuit board  100 . Specifically, the LED package  200  may be located at a boundary between two adjacent but not shorted together conductive members  130 . In an exemplary embodiment, the LED package  200  may overlap respective edges of two adjacent conductive members  130 . The specific structure of the LED package  200  will be described in detail later. 
         [0057]    The LED package  200  may be provided as a plurality of LED packages each containing one or more LED&#39;s or same and/or different output colors. In  FIG. 1 , eight LED packages  200  are illustrated. However, the present disclosure is not limited thereto, and n LED packages  200  may also be provided, where n is a natural number of two or more. The LED packages  200  may be separated from each other. In addition, the LED packages  200  may be arranged in a line. However, the present disclosure is not limited thereto, and the LED packages  200  may also be arranged in a matrix. Additionally, the illustrated sizes of the LED packages  200  are not to scale and the LED packages  200  may consume greater portions of the available surface area than what is illustrated. 
         [0058]      FIG. 2  is an enlarged view of a portion II of  FIG. 1 . Referring to  FIG. 2 , the conductive members  130  include a first conductive member  130   a  and a second conductive member  130   b . Here, the first conductive member  130   a  and the second conductive member  130   b  are relative features whose specifics depend on correspondingly specific aspects of the overlying LED package  200 . That is, if the LED package  200  has only two and opposed terminals, the conductive members  130  located on a first side of the LED package  200  may be the first conductive member  130   a , and the conductive members  130  located on the opposed other side of the LED package  200  may be the second conductive member  130   b . This is based on the LED package  200  shown in  FIG. 2 , where the latter is, a fourth LED package  200  from the left side of  FIG. 1 . In other words, the second conductive member  130   b  may be the same as a first conductive member defined based on a fifth LED package  200  from the left side of  FIG. 1 . 
         [0059]    There is a general spacing apart area between the first and second conductive members  130   a  and  130   b . However, the first conductive member  130   a  includes a first protrusion  130   a - 1  which protrudes into the general spacing apart area and extends toward the second conductive member  130   b . Similarly, the second conductive member  130   b  includes a second protrusion  130   b - 1  which protrudes into the general spacing apart area and extends toward the first conductive member  130   a  and optionally in at least one embodiment toward the first protrusion  130   a - 1 . The first protrusion  130   a - 1  and the second protrusion  130   b - 1  will be described in greater detail later. 
         [0060]    The specific structure of each of the LED packages  200  and the relationship between the LED packages  200  and the first and second conductive members  130   a  and  130   b  will now be described with reference to  FIG. 3 .  FIG. 3  is a cross-sectional view taken along the line III-III′ of  FIG. 2 . 
         [0061]    Referring to  FIG. 3 , an LED package  200  may include at least one LED chip such as the illustrated  210 , where the LED chip  210  has monolithically integrated therein, one or more light emitting diodes of same or different light emitting capabilities (e.g., same or different colors). The LED package  200  may further include a first lead frame  220   a , a second lead frame  220   b , a first wire  230   a , a second wire  230   b , a housing  240 , and a light-passing (e.g., transparent) encapsulant  250 . 
         [0062]    The LED chip  210  is a device that emits one or more lights in response to electric power applied thereto. The LED chip  210  is disposed on the second lead frame  220   b . Although not specifically shown in  FIG. 3 , the LED chip  210  includes a substrate, an N-type semiconductor layer, a P-type semiconductor layer, an active layer, an N-type electrode, and a P-type electrode. 
         [0063]    The substrate included in the LED chip  210  may mostly be a sapphire substrate. The N-type semiconductor layer and the P-type semiconductor layer may be formed of a nitride semiconductor such as GaN, AlGaN, InGaN, AIN, or AlInGaN. The active layer may be a light-emitting layer formed between the N-type semiconductor layer and the P-type semiconductor layer. The active layer may have a multi-quantum well (MQW) structure including an InGaN layer as a well and a GaN layer as a barrier layer. The N-type electrode may be ohmically connected to the N-type semiconductor layer, and the P-type electrode may be ohmically connected to the P-type semiconductor layer. The above configuration of the LED chip  210  can be modified into various forms known in the art to which the present disclosure of invention pertains. 
         [0064]    The first lead frame  220   a  may be located on a first side of the LED package  200 . In an exemplary embodiment, the first lead frame  220   a  may be formed of a conductive material having a step difference. The first lead frame  220   a  may be formed of the same material as the conductive members  130 . 
         [0065]    A first end of the first lead frame  220   a  may be electrically connected to the P-type electrode of the LED chip  210 . In addition, a second end of the first lead frame  220   a  which is opposite the first end of the first lead frame  220   a  may directly contact the first conductive member  130   a . That is, the first lead frame  220   a  may be electrically connected to the first conductive member  130   a.    
         [0066]    The second lead frame  220   a  may be located on a second side of the LED package  200  which is opposite the first side of the LED package  200 . In an exemplary embodiment, the second lead frame  220   b  may be formed of a conductive material having a step difference. The second lead frame  220   b  may be formed of the same material as the conductive members  130 . In addition, the second lead frame  220   b  may be formed of the same material as the first lead frame  220   a.    
         [0067]    A first end of the second lead frame  220   b  may be electrically connected to the P-type electrode of the LED chip  210 . In addition, a second end of the second lead frame  220   b  which is opposite the first end of the second lead frame  220   b  may directly contact the second conductive member  130   b . That is, the second lead frame  220   b  may be electrically connected to the second conductive member  130   b . In addition, as described above, the LED chip  210  may be located on a surface of the second lead frame  220   b . In addition to good electrical conductivity, each of the first and second lead frames  220   a - 220   b  may have the attribute of good thermal conductivity so that heat generated within the LED chip  210  may be appropriately dissipated by way of one or both of the lead frames  220   a - 220   b.    
         [0068]    The first lead frame  220   a  and the second lead frame  220   b  may be disposed opposite each other. Specifically, the first end of the first lead frame  220   a  and the first end of the second lead frame  220   b  may face each other. 
         [0069]    The first wire  230   a  may electrically connect the P-type electrode of the LED chip  210  and the first lead frame  220   a . The second wire  230   b  may electrically connect the N-type electrode of the LED chip  210  and the second lead frame  220   b.    
         [0070]    The housing  240  may contain and affix the LED chip  210  therein as well as also containing the first lead frame  220   a , the second lead frame  220   b , the first wire  230   a  and the second wire  230   b . At least one of the housing  240 , the first lead frame  220   a  and the second lead frame  220   b  is affixed to a corresponding one of the first conductive member  130   a  and the second conductive member  130   b . The housing  240  may have a recess formed in a portion thereof where the LED chip  210  is located. Since light is emitted from inside the recess, the planar area of the recess may be called a light-emitting window LW. In an exemplary embodiment, the housing  240  may be cup-shaped. In addition, the housing  240  may be manufactured by, but not limited to, injection molding. The housing  240  may be formed of an insulating material. In addition, the housing  240  may include a reflective material. That is, the housing  240  may reflect light emitted from the LED chip  210  in a desired direction. 
         [0071]    The encapsulant  250  may not only affix the LED chip  210  as well as the first wire  230   a  and the second wire  230   b  within the housing  240  but may also protect the LED chip  210 , the first wire  230   a , and the second wire  230   b  from external contaminants and other damaging effects. The encapsulant  250  may fill the recess formed in the housing  240 . In an exemplary embodiment, the encapsulant  250  may be formed of transparent silicon. In another exemplary embodiment, the encapsulant  250  may be formed of transparent resin. The encapsulant  250  may include one or more phosphors that convert part or all of a color of light emitted from the LED chip  210  into a respective one or more other colors. For example, the LED chip  210  may emit light in the blue end of the spectrum and the phosphors may convert part of that bluish light into red and green lights. 
         [0072]    The LED package  200  may be disposed on the first conductive member  130   a  and the second conductive member  130   b . The first conductive member  130   a  and the second conductive member  130   b  may be electrically connected to the LED chip  210  of the LED package  200 . That is, the first conductive member  130   a  and the second conductive member  130   b  may transfer an external voltage applied from the connector  120  (see  FIG. 1 ) to the LED chip  210 , thereby causing the LED chip  210  to emit light. 
         [0073]    The first protrusion  130   a - 1  and the second protrusion  130   b - 1  will now be described in detail with reference to  FIGS. 2 through 4 .  FIGS. 2 and 3  have been described above.  FIG. 4  is an enlarged view of a portion IV of  FIG. 2 , that is, a portion where the first protrusion  130   a - 1  and the second protrusion  130   b - 1  are located. 
         [0074]    The first protrusion  130   a - 1  may protrude from an edge of the first conductive member  130   a , which faces the second conductive member  130   b , toward the second conductive member  130   b . On the other hand, the second protrusion  130   b - 1  may protrude from an edge of the second conductive member  130   b , which faces the first conductive member  130   a , toward the first conductive member  130   a . The second protrusion  130   b - 1  can be omitted. That is, only the first protrusion  130   a - 1  may exist, and the second protrusion  130   b - 1  may not exist. 
         [0075]    Each of the first protrusion  130   a - 1  and the second protrusion  130   b - 1  may have a sharp or pointed end. In an exemplary embodiment, the first protrusion  130   a - 1  and the second protrusion  130   b - 1  may have a triangular shape as seen from one or both of the top plan view and side sectional view. In another exemplary embodiment, the first protrusion  130   a - 1  and the second protrusion  130   b - 1  may have a sharply tapered shape similar to the shape of the eye of a needle. However, the present disclosure of invention is not limited thereto, and the first protrusion  130   a - 1  and the second protrusion  130   b - 1  can have various shapes adapted for providing the spark gap functions described herein. 
         [0076]    An air or other gas layer may be interposed between the first protrusion  130   a - 1  and the second protrusion  130   b - 1 . However, the present disclosure of invention is not limited thereto, and an insulating layer with appropriate high voltage breakdown attributes may also be interposed between the first protrusion  130   a - 1  and the second protrusion  130   b - 1 . 
         [0077]    Referring to  FIG. 4 , the first protrusion  130   a - 1  and the second protrusion  130   b - 1  may face each other. In an exemplary embodiment, the first protrusion  130   a - 1  and the second protrusion  130   b - 1  may be symmetrical to each other with respect to a virtual line L that halves an area between the first conductive member  130   a  and the second conductive member  130   b . In addition, a minimum distance d1 between the first protrusion  130   a - 1  and the second protrusion  130   b - 1  may be smaller than a minimum distance d2 between the first conductive member  130   a  and the second conductive member  130   b  in a portion where the first protrusion  130   a - 1  and the second protrusion  130   b - 1  are not formed. Accordingly, when a dangerously high voltage (such as that from electrostatic discharge) is applied to the light source unit, an overcurrent may flow between the first protrusion  130   a - 1  and the second protrusion  130   b - 1 . Here, a spark may occur in a portion where the first protrusion  130   a - 1  and the second protrusion  130   b - 1  are located. That is, the first protrusion  130   a - 1  and the second protrusion  130   b - 1  may form a spark gap that breaks down and sparks when subjected to voltages above a predetermined threshold, thereby protecting the LED package  200  from electrostatic discharge (ESD) and electromagnetic interference (EMI). 
         [0078]    The above function will now be described in more detail with reference to  FIG. 5 .  FIG. 5  is an equivalent circuit diagram of a portion of the light source unit of  FIG. 1 . That is,  FIG. 5  is an equivalent circuit diagram of one LED package  200  and the circuit board  100  adjacent to the LED package  200 . 
         [0079]    Referring to  FIG. 5 , an LED  300  and an equivalent nonlinear resistor  410  may be connected in parallel. Here, the LED  300  may be the LED chip  210  described above, and the equivalent nonlinear resistor  410  may represent the electrical characteristics of the area between the first protrusion  130   a - 1  and the second protrusion  130   b - 1 . That is, the first protrusion  130   a - 1  and the second protrusion  130   b - 1  form the equivalent but nonlinear resistor  410  which is connected in parallel to the LED  300 . In accordance with the present disclosure, the resistance of the equivalent but nonlinear resistor  410  drops dramatically when voltage there across exceeds a predetermined threshold. Thus, when a high voltage exceeding that threshold is applied to the light source unit, it is possible to prevent a damaging overcurrent from flowing through the LED chip  210 . 
         [0080]    The light source unit according to the current embodiment can provide various effects in addition to the above-described function of protecting the LED chip  210 . For example (but not limited to this example), since a Zener diode is not included, the overall size of the LED package  200  can be reduced. A reduction in the size of the LED package  200  can directly lead to a reduction in the size of a final product, for example, the size of a display device. In addition, since the expensive Zener diode is not used, the time and cost needed to manufacture the LED package  200  and the light source unit having the LED packages with Zeners included can be reduced. Furthermore, the absence of the Zener diode can increase the size of the light-emitting window LW (see  FIG. 3 ), and the increased size of the light-emitting window LW can directly contribute to an increase in the optical efficiency of the LED package  200 . For example, the increased size of the light-emitting window LW can increase luminous intensity by approximately 5%. Accordingly, the number of LED packages  200  included in the light source unit can be reduced. 
         [0081]      FIGS. 6 through 9  are partial enlarged views of light source units according to other embodiments in accordance with the present disclosure. That is,  FIGS. 6 through 9  are enlarged views of first protrusions  130   a - 2 ,  130   a - 3 ,  130   a - 4  and  130   a - 5  and second protrusions  130   b - 2 ,  130   b - 3  and  130   b - 4  of the light source units. For convenience of description, elements substantially identical to those shown in the above-described figures are indicated by the same reference numerals, and thus a detailed description thereof will be omitted. 
         [0082]    Referring to  FIG. 6 , an end of each of the first protrusion  130   a - 2  and the second protrusion  130   b - 2  may have a curved shape. In an exemplary embodiment, each of the first protrusion  130   a - 2  and the second protrusion  130   b - 2  may be semicircular. However, the present teachings are not limited thereto, and one or both of the first protrusion  130   a - 2  and the second protrusion  130   b - 2  may instead be semielliptical or another curved shape. 
         [0083]    Referring to  FIG. 7 , each of the first protrusion  130   a - 3  and the second protrusion  130   b - 3  may include a plurality of sub-protrusions or fork tongs. All of the sub-protrusions in one embodiment may have substantially the same shape, for example, a triangle as viewed from at least one of top plan and side sectional views. In addition, the sub-protrusions may be disposed adjacent to each other. The sub-protrusions of the first protrusion  130   a - 3  may correspond to the sub-protrusions of the second protrusion  130   b - 3 , respectively. Specific designs of shapes and dimensions may vary depending on the electrical breakdown characteristics of the intervening material(s) between the plural sub-protrusions or fork tongs and the way in which electrical flux fields distribute therebetween before and after dielectric breakdown. 
         [0084]    Referring to  FIG. 8 , each of the first protrusion  130   a - 4  and the second protrusion  130   b - 4  may include a plurality of sub-protrusions as in  FIG. 7 . However, the sub-protrusions may have a different shape from the shape of the sub-protrusions shown in  FIG. 7 . That is, in the exemplary embodiment of  FIG. 8 , each of the sub-protrusions included in each of the first protrusion  130   a - 4  and the second protrusion  130   b - 4  may be curved or more specifically, semicircular. However, the shape of each of the sub-protrusions is not limited to the semicircular shape. 
         [0085]    Referring to  FIG. 9 , the second protrusion  130   b - 4  of  FIG. 8  may be omitted. That is, only the first protrusion  130   a - 5  may exist. In this case, the first protrusion  130   a - 5  may protrude further than the first protrusion  130   a - 4  shown in  FIG. 8 . 
         [0086]      FIG. 10  is a partial enlarged view of a light source unit according to another embodiment of the present disclosure of invention. That is,  FIG. 10  is an enlarged plan view of one LED package  200  and a printed circuit board  100  adjacent to the LED package  200 . For convenience of description, elements substantially identical to those shown in the above-described figures are indicated by the same reference numerals, and thus a detailed description thereof will be omitted. 
         [0087]    Referring to  FIG. 10 , a first conductive member  131   a  may include a plurality of first protrusions  131   a - 1 . Here, a protruding length of at least one of the first protrusions  131   a - 1  may be different from protruding lengths of the other first protrusions  131   a - 1 . In addition, a second conductive member  131   b  may include a plurality of second protrusions  131   b - 1 . Here, a protruding length of at least one of the second protrusions  131   b - 1  may be different from protruding lengths of the other second protrusions  131   b - 1 . 
         [0088]    The first protrusions  131   a - 1  may be arranged alternately with the second protrusions  131   b - 1 . In the exemplary embodiment of  FIG. 10 , the first protrusions  131   a - 1  and the second protrusions  131   b - 1  may be arranged alternately in a vertical direction. In  FIG. 10 , the LED  200  is disposed on one of the first protrusions  131   a - 1  that is disposed between two of the second protrusions  131   b - 1 . However, the present disclosure is not limited thereto, and the LED package  200  may also be disposed on a second protrusion  131   b - 1  that is disposed between two first protrusions  131   a - 1 . 
         [0089]    A boundary between the first conductive member  131   a  and the second conductive member  131   b  may be bent at least once. In an exemplary embodiment, the boundary between the first conductive member  131   a  and the second conductive member  131   b  may be in the shape of a winding river for example. That is, the boundary between the first conductive member  131   a  and the second conductive member  131   b  may be longer than when the boundary between the first conductive member  131   a  and the second conductive member  131   b  is formed like a straight line. A distance between the first conductive member  131   a  including the first protrusions  131   a - 1  and the second conductive member  131   b  including the second protrusions  131   b - 1  may be substantially the same in all areas. 
         [0090]    If the boundary between the first conductive member  131   a  and the second conductive member  131   b  is patterned by the first protrusions  131   a - 1  and the second protrusions  131   b - 1  as described above, the first conductive member  131   a  and the second conductive member  131   b  form a capacitor  420  (see  FIG. 11 ), thereby protecting the LED package  200  from ESD and EMI. This will now be described in more detail with reference to  FIG. 11 .  FIG. 11  is an equivalent circuit diagram of a portion of the light source unit shown in  FIG. 10 . That is,  FIG. 11  is an equivalent circuit diagram of one LED package  200  and the circuit board  100  adjacent to the LED package  200 . 
         [0091]    Referring to  FIG. 11 , an LED  300  and a capacitor  420  may be connected in parallel. Here, the LED  300  may be the LED chip  210  described above, and the capacitor  420  may be an area between the first conductive member  131   a  and the second conductive member  131   b . That is, the first conductive member  131   a  and the second conductive member  131   b  may form the capacitor  420  which is connected in parallel to the LED  300 . The dielectric of the so-formed capacitor  420  may be one that breaks down above a predetermined threshold voltage. Thus, when an excessively high voltage greater than the predetermined threshold voltage is applied to the light source unit, it is possible to prevent an overcurrent from flowing through the LED chip  210 . 
         [0092]      FIG. 12  is a partial enlarged view of a light source unit according to another embodiment of the present invention. That is,  FIG. 12  is an enlarged plan view of one LED package  200  and a circuit board  100  adjacent to the LED package  200 . For convenience of description, elements substantially identical to those shown in the above-described figures are indicated by the same reference numerals, and thus a detailed description thereof will be omitted. 
         [0093]    Referring to  FIG. 12 , a first protrusion  132   a - 1  protruding from a first conductive member  132   a  and a second protrusion  132   b - 1  protruding from a second conductive member  132   b  may be bent one or more times so as to form inductive windings that are spaced apart from one another by a predetermined distance. In an exemplary embodiment, the first protrusion  132   a - 1  and the second protrusion  132   b - 1  may be bent multiple times at an angle of 90 degrees in each bend. In addition, each of the first protrusion  132   a - 1  and the second protrusion  132   b - 1  may be bent multiple times in a clockwise direction or a counterclockwise direction to be electrically connected to the LED package  200 . In the exemplary embodiment of  FIG. 12 , the first protrusion  132   a - 1  and the second protrusion  132   b - 1  are bent multiple times in the clockwise direction while being spaced apart so as to thereby define an inductive-capacitive filtering structure that can protect the LED package  200  from high frequency ESD and/or EMI signals. Additionally, the dielectric material may be one that breaks down above a predetermined threshold voltage. The present embodiment is not limited to the inductive-capacitive filtering structure shown in  FIG. 11 . For example, the first protrusion  132   a - 1  and the second protrusion  132   b - 1  may also be bent multiple times in the counterclockwise direction. In this case, bent portions of the first protrusion  132   a - 1  may be located between portions of the second conductive member  132   b . In addition, bent portions of the second protrusion  132   b - 1  may be located between portions of the first conductive member  132   a.    
         [0094]    By increasing the length of the boundary between the first conductive member  132   a  and the second conductive member  132   b  as described above, the capacitance of the capacitor  420  formed by the first conductive member  132   a  and the second conductive member  132   b  can be increased and inductance may be added to the filtering structure. If desired, a ferromagnetic material may be laminated over the windings to further increase the inductance thereof. The added ferromagnetic material may be embedded as particles in a dielectric material that breaks down above a predetermined threshold voltage. 
         [0095]      FIG. 13  is a partial enlarged view of a light source unit according to yet another embodiment in accordance with the present disclosure of invention. That is,  FIG. 13  is an enlarged plan view of a portion where an LED package  201  is located.  FIG. 14  is a cross-sectional view taken along the line XIV-XIV′ of  FIG. 13 . For convenience of description, elements substantially identical to those shown in the above-described figures are indicated by the same reference numerals, and thus a detailed description thereof will be omitted. 
         [0096]    Referring to  FIGS. 13 and 14 , a first conductive member  133   a  and a second conductive member  133   b  included in the printed circuit board  100  may or may not themselves include ESD and/or EMI reducing/preventing protrusions. However, within the packagings of the LED packages  201 , at least a first lead frame  221   a  and a second lead frame  221   b  included in each LED package  201  includes ESD and/or EMI reducing/preventing protrusions. 
         [0097]    Specifically, the first lead frame  221   a  may include a first protrusion  221   a - 1  which protrudes toward the second lead frame  221   b . That is, the first protrusion  221   a - 1  may be formed at an end of the first lead frame  221   a  which faces the second lead frame  221   b . In addition, the second lead frame  221   b  may include a second protrusion  221   b - 1  which protrudes toward the first lead frame  221   a . That is, the second protrusion  221   b - 1  may be formed at an end of the second lead frame  221   b  which faces the first lead frame  221   a . A material of or within the housing  240  may be interposed between the first protrusion  221   a - 1  and the second protrusion  221   b - 1 . The interposed material of or within the housing  240  may be a dielectric one that breaks down above a predetermined threshold voltage. The second protrusion  221   b - 1  can be omitted when necessary. 
         [0098]    Referring to  FIG. 13 , the first protrusion  221   a - 1  and the second protrusion  221   b - 1  may face each other. In an exemplary embodiment, the first protrusion  221   a - 1  and the second protrusion  221   b - 1  may be symmetrical to each other with respect to a virtual line L′ that halves an area between the first lead frame  221   a  and the second lead frame  221   b . In addition, a minimum distance d1′ between the first protrusion  221   a - 1  and the second protrusion  221   b - 1  may be smaller than a minimum distance d2′ between the first lead frame  221   a - 1  and the second lead frame  221   b - 1  in a portion where the first protrusion  221   a - 1  and the second protrusion  221   b - 1  are not formed. Accordingly, when a high voltage is applied to the light source unit (in excess of the predetermined threshold voltage of the interposed material of or within the housing  240 ), an overcurrent may flow between the first protrusion  221   a - 1  and the second protrusion  221   b - 1  rather than passing through the LED  210 . Here, a spark may occur in a portion where the first protrusion  221   a - 1  and the second protrusion  221   b - 1  are located. That is, the first protrusion  221   a - 1  and the second protrusion  221   b - 1  may form a spark gap, thereby protecting the LED package  201  from ESD and/or EMI and/or reducing the effect of damages caused by such ESD and/or EMI. 
         [0099]      FIG. 15  is an exploded cross-sectional view of a backlight assembly according to an embodiment of the present disclosure of invention. For convenience of description, elements substantially identical to those shown in the above-described figures are indicated by the same reference numerals, and thus a detailed description thereof will be omitted. 
         [0100]    Referring to  FIG. 15 , the backlight assembly according to the current embodiment includes a light source unit ( 100 - 200 ) and an accommodating housing  500 . In addition, the backlight assembly according to the current embodiment may include an edge-lit light guide plate (LGP)  600 , a diffusion sheet  700 , and a reflective sheet  800 . 
         [0101]    The light source unit may include a circuit board  100  and an LED package  200  mounted on the circuit board  100 . Since this has been described above, a description thereof will be omitted. 
         [0102]    The accommodating housing  500  may house the light source unit. In addition, the accommodating housing  500  may house the LGP  600 , the diffusion sheet  700 , and the reflective sheet  800  which will be described later. The accommodating housing  500  may be formed of a hard metal material to protect the light source unit, the LGP  600 , the diffusion sheet  700 , and the reflective sheet  800 . 
         [0103]    The LGP  600  may be placed to face the LED package  200  of the light source unit. The LGP  600  may be shaped like a quadrangular plate. The LGP  600  includes an incident surface  610  adjacent to the LED package  200 , an exit surface  620  extending from a first end of the incident surface  610 , and a reflective surface  630  parallel to the exit surface  620  and extending from a second end of the incident surface  610  which is opposite the first end of the incident surface  610 . 
         [0104]    Light emitted from the LED package  200  may be incident upon the incident surface  610  of the LGP  600 . The light entering the LGP  600  through the incident surface  610  may exit the LGP  600  through the exit surface  620  or may be reflected by the reflective surface  630  and then exit the LGP  600  through the exit surface  620 . To increase the focusing efficiency of light entering the LGP  600 , a light-emitting surface  200 L of the LED package  200  may be placed parallel to the incident surface  610  of the LGP  600 . In  FIG. 15 , the light source unit is disposed on a side of the LGP  600 . However, the present disclosure of invention is not limited thereto, and the light source unit may also be disposed under the LGP  600 . 
         [0105]    The backlight assembly may further include the diffusion sheet  700  which is disposed on the exit surface  620  and the reflective sheet  800  which is disposed between the LGP  600  and the housing  500 . The reflective sheet  800  reflects light, which is leaked from the LGP  600 , back to the LGP  600 , and the diffusion sheet  700  diffuses light emerging from the LGP  600 . Accordingly, the luminance of the backlight assembly can be improved. 
         [0106]    The backlight assembly according to the current embodiment can protect devices (such as the light source unit) from ESD and/or EMI without using a Zener diode. In addition, since the backlight assembly includes the light source unit without the Zener diode, the overall size of the backlight assembly can be reduced. Furthermore, the removal of the Zener diode can increase the optical efficiency of the backlight assembly. In particular, the omission of the expensive Zener diode can reduce the cost and time needed to manufacture the backlight assembly. 
         [0107]    Embodiments in accordance with the present disclosure of invention may provide at least one of the following advantages. 
         [0108]    That is, it is possible to protect an LED from ESD and EMI without using a Zener diode. 
         [0109]    In addition, it is possible to reduce the size of an LED package and the cost required to manufacture the LED package. 
         [0110]    Furthermore, it is possible to increase the optical efficiency of the LED package. 
         [0111]    However, the effects of the present teachings are not restricted to the one set forth herein. While the present disclosure of invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art in view of the foregoing that various changes in form and details may be made therein without departing from the spirit and scope of the present teachings. It is therefore desired that the present embodiments be considered in all respects as illustrative and not restrictive.