Abstract:
Disclosed is a light-emitting module capable of not only improving appearance quality but also maximizing light efficiency. The disclosed light-emitting module comprises: a circuit board; a light-emitting diode chip which is flip-bonded on the circuit board; and a housing which is positioned on the circuit board and surrounds the light-emitting diode chip, wherein the housing has a recess and reflective part having a curvature structure formed on an inner wall of the recess.

Description:
TECHNICAL FIELD 
       [0001]    This patent document relates to a light emitting module including a light emitting module that can enhance appearance quality while maximizing luminous efficacy. 
       BACKGROUND 
       [0002]    Recently, with broad distribution of digital cameras that can photograph an object and record photographed data on a recording medium such as a memory, mobile terminals, such as a mobile phone, which includes a camera module as a medium for transmission of video information, have been developed and distributed in the art. 
         [0003]    The camera module of the mobile phone includes an image sensor configured to receive external light and recognize the received light as an image, and a light emitting module which, for example, manually supplies light to an object in order to satisfy various consumer demands. 
         [0004]    The light emitting module used in the camera module selectively supplies light depending upon photographing environments. Thus, the light emitting module resides around the camera module and is exposed to the outside. 
         [0005]    Since a typical light emitting module used in the camera module includes yellow phosphors placed on a blue light emitting diode, the yellow phosphors can be observed by the naked eye when the light emitting module is not operated, thereby causing a problem of deterioration in appearance quality. 
         [0006]    In order to satisfy requirement for enhanced appearance quality and high brightness of the light emitting module, various studies have been actively carried out on enhancement of luminous efficacy through reduction in light loss. 
       SUMMARY 
       [0007]    Exemplary embodiments of the disclosed technology provide a light emitting module capable of enhancing appearance quality such as disconnection while maximizing luminous efficacy. 
         [0008]    In accordance with exemplary embodiments of the disclosed technology, a light emitting module includes: a circuit board; a light emitting diode chip flip-bonded to the circuit board; and a housing residing on the circuit board and surrounding the light emitting diode chip, wherein the housing has a recess and a reflective part having a curved structure formed on an inner wall of the recess. With the structure, the light emitting module can improve luminous efficacy. 
         [0009]    In some implementations, the reflective part includes at least two reflective regions, each reflective region formed at different location along a height of the housing. 
         [0010]    In some implementations, the reflective part includes a first reflective portion, and a second reflective portion, wherein the second reflective portion is placed to reach a first height above the circuit board and the first reflective portion is placed above the second reflective portion to reach a second height above the first height, and wherein each of the first and second reflective portions includes at least two reflective regions each having a curved structure and placed on different locations along a height of the housing. 
         [0011]    In some implementations, the reflective regions of the first reflective portion continuously extend parallel to each other along an inner wall of the housing. 
         [0012]    In some implementations, the second reflective portion includes protrusions protruding in a lateral direction of the light emitting diode chip, and the protrusions are arranged at regular intervals along a side surface of the light emitting diode chip. 
         [0013]    In some implementations, the protrusions face the side surface of the light emitting diode chip. 
         [0014]    In some implementations, the second reflective portion includes a step portion placed at an interface between the first reflective portion and the protrusions. 
         [0015]    In some implementations, the housing includes a plurality of indentations formed at outer lower ends of the housing. 
         [0016]    In some implementations, at least one of the indentations is configured to receive an electronic device. 
         [0017]    In some implementations, the housing further includes a plurality of bumps protruding upwards from an upper surface of the housing and a lens is disposed inside the bumps on the upper surface of the housing. 
         [0018]    In some implementations, the housing includes a plurality of receiving grooves formed on an upper surface of the housing. In some implementations, the lens is disposed on the upper surface of the housing and includes a plurality of bumps formed on a lower surface of the housing and arranged in the receiving grooves. 
         [0019]    In some implementations, the light emitting diode chip includes a wavelength conversion layer covering upper and lower surfaces of a substrate having a semiconductor layer and an electrode pad, and a TiO 2  diffusion layer covering the wavelength conversion layer. 
         [0020]    In some implementations, the housing includes an upper surface and a bump formed on the upper surface, the bump being placed near the reflective part. 
         [0021]    In some implementations, the light emitting module further includes a lens disposed on the housing, wherein the lens has a step structure at an edge of a lower surface of the lens and a Fresnel lens structure inside the step structure. 
         [0022]    In some implementations, wherein the step structure faces the upper surface and the bump of the housing. 
         [0023]    In some implementations, the circuit board includes a recess receiving the light emitting diode chip, an inner side surface of the recess extending from the reflective part. 
         [0024]    In some implementations, the light emitting module further includes a silver (Ag) coating formed on the reflective part. 
         [0025]    In some implementations, the light emitting module further includes: a lens disposed on the housing; and a bonding structure attaching the lens to the housing, wherein the lens includes at least one of silicone, epoxy, glass, or PMMA, and the bonding structure includes an epoxy resin. 
         [0026]    In some implementations, the circuit board includes a lead frame or a conductive pattern and includes a printed circuit board (PCB) or a ceramic substrate. 
         [0027]    According to exemplary embodiments of the disclosed technology, a reflective part having a concavely curved structure is provided along an inner side surface of a recess of a housing formed of or including metal such that light emitted from the light emitting diode chip can be reflected along various paths by the reflective part. Accordingly, the light emitting module according to the exemplary embodiments of the disclosed technology can maximize luminous efficacy by minimizing internal light loss. 
         [0028]    Furthermore, according to the exemplary embodiments of the disclosed technology, the housing has a plurality of reflective regions each having a curved structure and divided along a height of an inner side of a recess such that light emitted from the light emitting diode chip can be reflected in various directions by the reflective regions, thereby maximizing luminous efficacy. 
         [0029]    Furthermore, the light emitting module according to the exemplary embodiments of the disclosed technology may further include a TiO 2  diffusion layer covering a wavelength conversion layer such that the wavelength conversion layer including a yellow phosphor layer is covered with white. Thus, it is possible to enhance appearance quality of the light emitting module. 
         [0030]    In addition, according to the exemplary embodiments of the disclosed technology, a contact area between the housing and a lens is increased through a step structure of the lens, thereby enhancing adhesion therebetween. Further, the lens is aligned on the housing by the step structure, thereby minimizing an alignment error. 
     
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         [0031]      FIG. 1  is a perspective view of an exemplary light emitting module according to a first exemplary embodiment of the disclosed technology. 
           [0032]      FIG. 2  is a plan view of the light emitting module shown in  FIG. 1 . 
           [0033]      FIG. 3  is a cross-sectional view of the light emitting module taken along line I-I′ of  FIG. 1 . 
           [0034]      FIG. 4  ( a ) is a bottom view of the light emitting diode chip shown in  FIG. 1  and  FIG. 4  ( b ) is a cross-sectional view of the light emitting module taken along line A-A of  FIG. 4  ( a ). 
           [0035]      FIG. 5  is a plan view of an exemplary light emitting module according to a second exemplary embodiment of the disclosed technology. 
           [0036]      FIG. 6  is a cross-sectional view of the light emitting module taken along line II-IF of  FIG. 5 . 
           [0037]      FIG. 7  is a plan view of a light emitting module according to a third exemplary embodiment of the disclosed technology. 
           [0038]      FIG. 8  is a cross-sectional view taken along line III-III′ of  FIG. 7 . 
           [0039]      FIG. 9  is a perspective view of an exemplary light emitting module according to a fourth exemplary embodiment of the disclosed technology. 
           [0040]      FIG. 10  is a sectional view of an exemplary light emitting module according to a fifth exemplary embodiment of the disclosed technology. 
           [0041]      FIG. 11  is a sectional view of an exemplary light emitting module according to a sixth exemplary embodiment of the disclosed technology. 
           [0042]      FIG. 12  is a sectional view of an exemplary light emitting module according to a seventh exemplary embodiment of the disclosed technology. 
       
    
    
     DETAILED DESCRIPTION 
       [0043]    Hereinafter, exemplary embodiments of the disclosed technology will be described in more detail with reference to the accompanying drawings. The following embodiments are provided by way of example so as to facilitate the understanding of some implementations of the disclosed technology to those skilled in the art to which the disclosed technology pertains. Accordingly, the disclosed technology is not limited to the embodiments disclosed herein and may also be implemented in different forms. In the drawings, widths, lengths, thicknesses, and the like of elements may be exaggerated for clarity and descriptive purposes. Throughout the specification, like reference numerals denote like elements having the same or similar functions. 
         [0044]      FIG. 1  is a perspective view of a light emitting module according to a first exemplary embodiment of the disclosed technology,  FIG. 2  is a plan view of the light emitting module shown in  FIG. 1 , and  FIG. 3  is a cross-sectional view of the light emitting module taken along line I-I′ of  FIG. 1 . 
         [0045]    Referring to  FIG. 1  to  FIG. 3 , a light emitting module  100  according to the first exemplary embodiment of the disclosed technology includes a circuit board  110 , a housing  120 , a light emitting diode chip  10 , and a lens  150 . 
         [0046]    The circuit board  110  includes a lead frame (not shown) or a conductive pattern (not shown). The circuit board  110  may be or include a printed circuit board or a ceramic substrate. 
         [0047]    The housing  120  envelops or surrounds the light emitting diode chip  10  and resides on the circuit board  110 . The housing  120  is formed of or includes a metallic material and may be attached to an upper side of the circuit board  110  by a soldering process or a silicone resin. 
         [0048]    The housing  120  has a recess formed at a central region thereof, and includes a reflective part  130  formed on an inner side surface of the recess, a plurality of bumps  121  formed on an upper surface of the housing  120 , and a plurality of indentations  122  disposed at outer corners of the housing  120 . 
         [0049]    The reflective part  130  has a curved structure extending along the inner side surface of the recess. 
         [0050]    The reflective part  130  has a function of reflecting light emitted from the light emitting diode chip  10  in various directions to enhance luminous efficacy of the light emitting module  100 . The reflective part  130  may include a highly reflective material coating. For example, Ag may be coated onto the reflective part  130 . Ag may be coated onto the entirety of the housing  120  and may be coated onto the circuit board  110 . 
         [0051]    Light emitted from the light emitting diode chip  10  may be reflected in various directions at reflection points on the curved structure of the reflective part  130 , thereby preventing loss of light laterally emitted from the light emitting diode chip  10 . 
         [0052]    The plurality of indentations  122  provide spaces in which electronic devices such as Zener diodes (not shown) can be mounted in the light emitting module  100 . 
         [0053]    The indentations  122  are arranged at regular intervals along an outer lower portion of the housing  120 . For example, the indentations  122  are placed at lower corers of the housing  120 . 
         [0054]    Although the indentations  122  are illustrated as being formed at the corners of the housing  120  such that the circuit board  110  is partially exposed therethrough in this exemplary embodiment, it should be understood that the disclosed technology is not limited thereto and the housing  120  may include an indentation structure formed along a lower part thereof so as to expose the circuit board  110 . 
         [0055]    The plural indentations  122  are separated from the recess in which the light emitting diode chip  10  is disposed, thereby enhancing luminous efficacy. For example, in a typical light emitting module, a light emitting diode chip and electronic devices are disposed in a recess, so that light emitted from the light emitting diode chip is absorbed or reflected by the electronic devices, thereby deteriorating luminous efficacy of the light emitting module. In the exemplary embodiment of the disclosed technology, the indentations  122  are formed to allow the electronic devices to be separated from the recess and mounted on the circuit board  110 , thereby preventing deterioration in luminous efficacy due to absorption or reflection of light by the electronic devices. 
         [0056]    According to this exemplary embodiment, the light emitting module  100  includes a Zener diode (not shown) disposed in one of the plural indentations  122 . The Zener diode has a function of preventing damage to the light emitting diode chip  10  by static electricity from the outside. That is, the Zener diode allows the light emitting module  100  to be stably operated. 
         [0057]    The bumps  121  have a function of fixing the position of the lens  150  by aligning the lens  150 . The bumps  121  may be separated by a certain distance from the upper surface of the housing  120  and protrude upwards from the upper surface of the housing  120 . 
         [0058]    Inner surfaces of the bumps  121  may face an outer surface of the lens  150 . 
         [0059]    The lens  150  has a flat upper surface and includes a wedge structure on a lower surface thereof. It should be understood that the structure of the lens  150  is not limited thereto and may be modified in various ways. For example, the lens  150  may be or include a Fresnel lens. The Fresnel lens may have a plurality of patterns corresponding to the shape of the recess. For example, the plurality of patterns may have a circular structure corresponding to a circular structure of the recess. In some implementations, the plurality of patterns may have a different shape from the shape of the recess. For example, the plurality of patterns may have a quadrangular structure that is different from the circular structure of the recess. 
         [0060]    The lens  150  is aligned on the upper surface of the housing  120  by the bumps  121 . 
         [0061]    Although not shown in the drawings, the lens  150  may be coupled to the upper surface of the housing by a bonding structure or member (not shown) or an adhesive material (not shown). The lens  150  may be formed of or include silicone, epoxy, glass or PMMA, without being limited thereto. In addition, the bonding member or structure (not shown) or the adhesive material (not shown) may be formed of or include an epoxy resin. 
         [0062]    According to this exemplary embodiment, the housing  120  is formed of or includes a metallic material, and includes the reflective part  130  of the concavely curved structure along the inner side surface of the recess to reflect light emitted from the light emitting diode chip  10  in various directions. Accordingly, the light emitting module  100  according to this exemplary embodiment can minimize internal light loss, thereby maximizing luminous efficacy. 
         [0063]    The light emitting diode chip  10  will be described in more detail with reference to  FIG. 4 . 
         [0064]      FIG. 4(   a ) is a bottom view of the light emitting diode chip shown in  FIG. 1  and  FIG. 4(   b ) is a cross-sectional view of the light emitting module taken along line A-A of  FIG. 4  ( a ). 
         [0065]    Referring to  FIGS. 3 and 4 , the light emitting diode chip  10  according to this exemplary embodiment is directly flip-bonded to the circuit board  110  without using a bonding wire. Since the bonding wire is not used upon bonding of the light emitting diode chip to the circuit board  110 , the light emitting module does not require a molding part for protection of the bonding wire or removal of part of a wavelength conversion layer  50  to expose a bonding pad. Thus, use of the light emitting diode chip  10  allows removal of color deviation or bright spots, thereby simplifying a module fabrication process as compared with use of a light emitting diode chip requiring a bonding wire. 
         [0066]    In some implementations, the light emitting diode chip  10  is a flip-chip type semiconductor chip formed of or including a gallium nitride-based compound semiconductor and can emit light in the ultraviolet or blue wavelength band. 
         [0067]    The light emitting diode chip  10  includes the wavelength conversion layer  50 . 
         [0068]    The wavelength conversion layer  50  covers the light emitting diode chip  10 . As shown in the drawings, the wavelength conversion layer  50 , for example, a phosphor layer, may be formed on the light emitting diode chip  10  by conformal coating and convert wavelengths of light emitted from the light emitting diode chip  10 . The wavelength conversion layer  50  is coated onto the light emitting diode chip  10  to cover upper and side surfaces of the light emitting diode chip  10 . 
         [0069]    According to this exemplary embodiment, for example, when the light emitting diode chip  10  emits blue light, the wavelength conversion layer  50  is composed of or includes a yellow phosphor layer on the light emitting diode chip  10 . 
         [0070]    The light emitting diode chip  10  includes a TiO 2  diffusion layer  70  covering the wavelength conversion layer  50 . 
         [0071]    The TiO 2  diffusion layer  70  may cover both upper and side surfaces of the wavelength conversion layer  50 . 
         [0072]    The TiO 2  diffusion layer  70  covers the wavelength conversion layer  50 , which exhibits a yellow color due to the yellow phosphor layer, and converts the light passing through the wavelength conversion layer  50  into white light, thereby enhancing appearance quality. 
         [0073]    In this exemplary embodiment, the wavelength conversion layer  50  formed by conformal coating and the TiO 2  diffusion layer  70  may be previously formed in fabrication of the light emitting diode chip  10  to be mounted together with the light emitting diode chip  10  on the circuit board  110 . 
         [0074]    Hereinafter, a method for fabricating the light emitting diode chip  10  will be schematically described in order to aid in understanding of some implementations of the disclosed technology. 
         [0075]    A first conductive type semiconductor layer  23  is formed on a growth substrate  21 , and a plurality of mesas M separated from each other is formed on the first conductive type semiconductor layer  23 . Each of the mesas M includes an active layer  25  and a second conductive type semiconductor layer  27 . The active layer  25  is interposed between the first conductive type semiconductor layer  23  and the second conductive type semiconductor layer  27 . Reflective electrodes  30  are placed on the plurality of mesas M, respectively. 
         [0076]    The plurality of mesas M may be formed by growing epitaxial layers including the first conductive type semiconductor layer  23 , the active layer  25  and the second conductive type semiconductor layer  27  on the growth substrate  21  by metal organic vapor deposition or the like, followed by patterning the second conductive type semiconductor layer  27  and the active layer  25  so as to expose the first conductive type semiconductor layer  23 . The plurality of mesas M may have inclined side surfaces, which may be formed by a technology such as photoresist reflow. The inclined profiles of the mesas M enhance efficiency in extraction of light generated in the active layer  25 . 
         [0077]    As shown, the plurality of mesas M may have an elongated shape and extend parallel to each other in one direction. Such a shape simplifies formation of the plurality of mesas M having the same shape in plural chip areas on the growth substrate  21 . 
         [0078]    On the other hand, although the reflective electrode  30  can be formed on each of the mesas M after formation of the plural mesas M, it should be understood that the disclosed technology is not limited thereto and the reflective electrodes  30  may be previously formed on the second conductive type semiconductor layer  27  after growth of the second conductive type semiconductor layer  27  and before formation of the mesas M. The reflective electrode  30  covers substantially the entirety of an upper surface of the mesa M and has substantially the same shape as that of the mesa M in plan view. 
         [0079]    The reflective electrodes  30  include a reflective layer  28  and may further include a barrier layer  29 . The barrier layer  29  may cover an upper surface and a side surface of the reflective layer  28 . 
         [0080]    After formation of the plurality of mesas M, the first conductive type semiconductor layer  23  may also be subjected to etching along an edge thereof. As a result, the upper surface of the substrate  21  can be exposed. The first conductive type semiconductor layer  23  may also have an inclined side surface. 
         [0081]    A lower insulation layer  31  is formed to cover the plurality of mesas M and the first conductive type semiconductor layer  23 . The lower insulation layer  31  has openings in certain areas such that electrical connection to the first conductive type semiconductor layer  23  and the second conductive type semiconductor layer  27  can be achieved therethrough. For example, the lower insulation layer  31  may have openings that expose the first conductive type semiconductor layer  23  and openings that expose the reflective electrodes  30 . 
         [0082]    A current spreading layer  33  is formed on the lower insulation layer  31 . The current spreading layer  33  covers the plurality of mesas M and the first conductive type semiconductor layer  23 . In addition, the current spreading layer  33  has openings formed in upper areas of the mesas M and exposing the reflective electrodes, respectively. The current spreading layer  33  may form ohmic contact with the first conductive type semiconductor layer  23  through the openings of the lower insulation layer  31 . The current spreading layer  33  is insulated from the plurality of mesas M and the reflective electrodes  30  by the lower insulation layer  31 . 
         [0083]    An upper insulation layer  35  is formed on the current spreading layer  33 . The upper insulation layer  35  has an opening that exposes the current spreading layer  33 , and openings that expose the reflective electrodes  30 . 
         [0084]    A first pad  37   a  and a second pad  37   b  are formed on the upper insulation layer  35 . The first pad  37   a  is connected to the current spreading layer  33  through the opening of the upper insulation layer  35 , and the second pad  37   b  is connected to the reflective electrodes  30  through the openings of the upper insulation layer  35 . The first pad  37   a  and the second pad  37   b  may be used as pads for SMT or bump connection to mount a light emitting diode on a sub-mount, a package or a printed circuit board. 
         [0085]    The light emitting diode chip  10  is formed with a wavelength conversion layer  50 , which covers the entirety of the light emitting diode chip  10  excluding one surface of each of the first and second pads  37   a  and  37   b  to be connected to a package or a printed circuit board. 
         [0086]    In addition, the light emitting diode chip  10  is formed with a TiO 2  diffusion layer  70  covering the wavelength conversion layer  50 . 
         [0087]      FIG. 5  is a plan view of a light emitting module according to a second exemplary embodiment of the disclosed technology, and  FIG. 6  is a cross-sectional view of the light emitting module taken along line II-IF of  FIG. 5   
         [0088]    Referring to  FIG. 5  and  FIG. 6 , a light emitting module  200  according to the second exemplary embodiment of the disclosed technology includes the same structure as that of the light emitting module  100  (see  FIG. 1 ) according to the first exemplary embodiment excluding a housing  220 , and thus the same components are indicated by the same reference numerals and detailed descriptions thereof are omitted. 
         [0089]    The housing  220  envelops a light emitting diode chip  10  and resides on a circuit board  110 . The housing  220  is formed of a metallic material and may be attached to an upper side of the circuit board  110  via a soldering process or a silicone resin. 
         [0090]    The housing  220  has a recess formed at a central region thereof, and includes a reflective part  230  formed on an inner side surface of the recess, a plurality of bumps  221  formed on an upper surface of the housing  220 , and a plurality of indentations  222  disposed at outer corners of the housing  220 . 
         [0091]    The reflective part  230  has a curved structure extending continuously along the inner side surface of the recess. The reflective part  230  may include a highly reflective material coating. For example, Ag may be coated onto the reflective part  230 . Ag may be coated onto the entirety of the housing  220  and may be coated onto the circuit board  110 . The reflective part  230  has first to fourth reflective regions  231  to  234  divided in an upward direction with reference to the circuit board  110 . 
         [0092]    The first to fourth reflective regions  231  to  234  may be divided according to heights h 1  to h 4  of the housing  230 . 
         [0093]    Each of the first to fourth reflective regions  231  to  234  has a curved structure extending continuously in the horizontal direction. For example, the first to fourth reflective regions  231  to  234  have a curved structure that surrounds the light emitting diode chip  10 . 
         [0094]    Light emitted from the light emitting diode chip  10  may be reflected in various directions by the curved structures of the first to fourth reflective regions  231  to  234  divided according to the heights h 1  to h 4  of the housing  220 . 
         [0095]    According to the second exemplary embodiment of the disclosed technology, the reflective part  230  includes the first to fourth reflective regions  231  to  234  divided according to the heights h 1  to h 4  of the housing  220  such that light emitted from the light emitting diode chip  10  is reflected in various directions by these reflective regions, thereby enhancing luminous efficacy of the light emitting module  200 . 
         [0096]    Light emitted from the light emitting diode chip  10  may be reflected in various directions at reflection points on the curved structure of the reflective part  230 , thereby preventing loss of light laterally emitted from the light emitting diode chip  10 . 
         [0097]    A plurality of indentations  222  and a plurality of bumps  221  are similar to those of the light emitting module  100  (see  FIG. 1 ) according to the first exemplary embodiment, and detailed descriptions thereof are omitted. 
         [0098]    Although the reflective part  230  according to the second exemplary embodiment is illustrated as having the first to fourth reflective regions  231  to  234  each having the curved structure and divided according to the heights h 1  to h 4  of the housing  220 , it should be understood that the disclosed technology is not limited thereto and the reflective part  230  may include any structures wherein the reflective part  230  is divided into at least two regions according to the height of the housing  220 . 
         [0099]    In the light emitting module  200  according to the second exemplary embodiment described above, the housing  220  formed of or including the metallic material has the reflective part  230  formed on the inner side surface of the recess, in which the reflective part  230  includes the first to fourth reflective regions  231  to  234  each having the curved structure and divided according to the heights h 1  to h 4  of the housing  220 , whereby light emitted from the light emitting diode chip  10  can be reflected along various paths. Accordingly, the light emitting module  200  according to this exemplary embodiment can maximize luminous efficacy by minimizing internal light loss. 
         [0100]      FIG. 7  is a plan view of a light emitting module according to a third exemplary embodiment of the disclosed technology, and  FIG. 8  is a cross-sectional view taken along line III-III′ of  FIG. 7 . 
         [0101]    Referring to  FIG. 7  and  FIG. 8 , a light emitting module  300  according to a third exemplary embodiment of the disclosed technology includes the same structure as that of the light emitting module  100  (see  FIG. 1 ) according to the first exemplary embodiment excluding a housing  320 , and thus the same components are indicated by the same reference numerals and detailed descriptions thereof are omitted. 
         [0102]    The housing  320  envelops a light emitting diode chip  10  and resides on a circuit board  110 . The housing  320  is formed of or includes a metallic material and may be attached to an upper side of the circuit board  110  by a soldering process or a silicone resin. 
         [0103]    The housing  320  has a recess formed at a central region of the housing  320 , and includes first and second reflective portions  330  and  340  formed on an inner side surface of the recess, a plurality of bumps  321  formed on an upper surface of the housing  120 , and a plurality of indentations  322  disposed at outer corners of the housing  320 . 
         [0104]    The second reflective portion  340  is placed within a first height h 1  with reference to the circuit board  110 , and the first reflective portion  330  is placed within a fifth height h 5 , which is defined as a total height of the housing  320  except the first height h 1 . Each of the first and second reflective portions  330 ,  340  may include a highly reflective material coating. For example, Ag may be coated onto each of the first and second reflective portions  330  and  340 . Ag may be coated onto the entirety of the housing  320  and may be coated onto the circuit board  110 . 
         [0105]    The first reflective portion  330  has a curved structure extending continuously along the inner side surface of the recess. 
         [0106]    The first reflective portion  330  has first to fourth reflective regions  331  to  334  divided in the upward direction above the first height h 1  with reference to the circuit board  110 . 
         [0107]    The first to fourth reflective regions  331  to  334  may be divided according to a height of the housing  320 . That is, the first to fourth reflective regions  331  to  334  may be divided above the first height h 1  of the housing  320 . 
         [0108]    Each of the first to fourth reflective regions  331  to  334  has a curved structure extending continuously in the horizontal direction. More specifically, the first to fourth reflective regions  331  to  334  have a curved structure that envelops the light emitting diode chip  10 . 
         [0109]    Light emitted from the light emitting diode chip  10  may be reflected in various directions by the curved structures of the first to fourth reflective regions  331  to  334  divided within the fifth height h 5  of the housing  320  except the first height h 1 . 
         [0110]    The second reflective portion  340  may include sections arranged at constant intervals in the horizontal direction within the first height h 1 . 
         [0111]    The second reflective portion  340  has a function of compensating for a gap between both sides of the light emitting diode chip  10  and the housing  320 . For example, a gap between a side surface of the light emitting diode chip  10  and a lower end of an inner side surface of the housing  320  can vary depending upon the structure of the light emitting diode chip  10 . For example, a distance between a corner of the light emitting diode chip  10  and the inner side surface of the housing  320  is narrower than a side surface of the light emitting diode chip  10  and the inner side surface of the housing  320 . Thus, light reflected by the housing  320  can be minutely non-uniform on the corner and the side surface of the light emitting diode chip  10 . According to this exemplary embodiment of the disclosed technology, the second reflective portion  340  has a function of compensating for non-uniform light due to the gap between the side surface of the light emitting diode chip  10  and the lower end of the inner side surface of the housing  320 . 
         [0112]    The second reflective portion  340  has a plurality of sections formed along the inner side surface of the recess at different heights and surrounding four side surfaces of the light emitting diode chip  10 . 
         [0113]    The plurality of sections of the second reflective portion  340  are structured to have four identical regions corresponding to and opposite the four side surfaces of the light emitting diode chip  10  in the plan view of  FIG. 7 . 
         [0114]    The second reflective portion  340  includes protrusions  341 , which face the side surface of the light emitting diode chip  10  within the height h 1  of the housing  320  and protrudes towards the inner surface of the light emitting diode chip  10 , and a step portion  343  formed by formation of the protrusions  341 . 
         [0115]    Each of the protrusions  341  includes fifth and sixth reflective regions  341   a  and  341   b  divided in the upward direction of the housing  320 . 
         [0116]    The fifth and sixth reflective regions  341   a  and  341   b  may be divided according to the height of the housing  320  within the first height h 1 . 
         [0117]    The fifth and sixth reflective regions  341   a  and  341   b  have curved structures divided within the second reflective portion  340 . 
         [0118]    Light emitted outwards from the light emitting diode chip  10  is reflected in various directions by the curved structures of the fifth and sixth reflective regions  341   a  and  341   b  which are divided within the first height h 1  of the housing  320 . 
         [0119]    The first height h 1  is greater than or the same as the height of the light emitting diode chip  10 . 
         [0120]    Although the second reflective portion  340  is illustrated as having the two curved structures of the fifth and sixth reflective regions  341   a ,  341   b , it should be understood that the disclosed technology is not limited thereto and the second reflective portion  340  may have at least three curved structures divided from one another. 
         [0121]    The step portion  343  may be formed at an interface between the protrusions  341  and the first reflective portion  330 . 
         [0122]    A plurality of indentations  322  and a plurality of bumps  321  are similar to those of the light emitting module  100  (see  FIG. 1 ) according to the first exemplary embodiment, and detailed descriptions thereof are omitted. 
         [0123]    The first and second reflective portions  330  and  340  according to the third exemplary embodiment are illustrated as having the first to sixth reflective regions  331  to  334 ,  341   a , and  341   b  divided according to the height of the housing  320  to reflect light emitted from the light emitting diode chip  10  in various directions, thereby enhancing luminous efficacy of the light emitting module  300 . 
         [0124]    Furthermore, in the light emitting module  300  according to the third exemplary embodiment of the disclosed technology, light emitted from a side surface of the light emitting diode chip  10  is reflected by the second reflective portion  340  to compensate for a minute difference of reflected light due to the gap between the light emitting diode chip  10  and the lower end of the inner surface of the housing  320 , thereby preventing light loss while realizing generally uniform light. 
         [0125]      FIG. 9  is a perspective view of a light emitting module according to a fourth exemplary embodiment of the disclosed technology. 
         [0126]    Referring to  FIG. 9 , a light emitting module  400  according to the fourth exemplary embodiment of the disclosed technology includes a circuit board  110 , a housing  420 , a light emitting diode chip (not shown), and a lens  450 . 
         [0127]    The housing  420  envelops the light emitting diode chip (not shown) and resides on the circuit board  110 . The housing  420  is formed of or including a metallic material and may be attached to an upper side of the circuit board  110  via a soldering process or a silicone resin. 
         [0128]    The housing  420  has a recess formed at a central region of the housing  420 , and includes a reflective part (not shown) formed on an inner side surface of the recess, a plurality of receiving grooves  421  formed on an upper surface of the housing  420 , and a plurality of indentations  422  disposed at outer corners of the housing  420 . 
         [0129]    The plural receiving grooves  421  may be formed near corners of the upper surface of the housing  420 . The plurality of receiving grooves  421  receive a plurality of bumps  451  formed on a lower surface of the lens  450 , respectively. 
         [0130]    Here, the bumps  451  are formed near corners of the lower surface of the lens  450  and protrude downwards from the lens  450 . The bumps  451  and the receiving grooves  421  may have the same shape. 
         [0131]    The lens  450  is aligned on the upper surface of the housing  420  when the plural bumps  451  are received in the plural receiving grooves  421  of the housing  420 . 
         [0132]    Although not shown in the drawings, the lens  450  may be coupled to the upper surface of the housing  420  via a bonding member or structure (not shown) or an adhesive material (not shown). 
         [0133]    The plurality of indentations  422  provide spaces in which electronic devices such as Zener diodes (not shown) can be mounted in the light emitting module  400 . 
         [0134]    The indentations  422  are arranged at regular intervals along an outer lower portion of the housing  420 . For example, the indentations  422  are placed at lower corers of the housing  420 . 
         [0135]    Although the indentations  422  are illustrated as being formed at the corners of the housing  420  such that the circuit board  110  is partially exposed therethrough in this exemplary embodiment, it should be understood that the disclosed technology is not limited thereto and the housing  420  may include an indentation structure formed along a lower end thereof to expose the circuit board  110 . 
         [0136]    According to this exemplary embodiment, the light emitting module  400  includes a Zener diode (not shown) disposed in one of the plurality of indentations  422 . 
         [0137]    The housing  420  of the light emitting module  400  according to the fourth exemplary embodiment of the disclosed technology may have one of the inner surface structures of the housings according to the first to third exemplary embodiments of the disclosed technology. 
         [0138]      FIG. 10  is a sectional view of a light emitting module according to a fifth exemplary embodiment of the disclosed technology. 
         [0139]    Referring to  FIG. 10 , a light emitting module  500  according to the fifth exemplary embodiment of the disclosed technology includes the same structure as that of the light emitting module  100  (see  FIG. 3 ) according to the first exemplary embodiment and includes different structures for a housing  520  and a lens  550 . The same components are indicated by the same reference numerals and detailed descriptions thereof are omitted. 
         [0140]    The housing  520  resides on a circuit board  110  and surrounds a light emitting diode chip  10  mounted on the circuit board  110 . The circuit board  110  may include a lead frame (not shown) or a conductive pattern (not shown), and may be a printed circuit board or a ceramic substrate. The housing  520  has a recess formed at a central region of the housing  520 , and includes a bump  521  formed on an upper surface of the housing  520  and a reflective part  530  formed on an inner side surface of the recess. 
         [0141]    The reflective part  530  has a function of reflecting light emitted from the light emitting diode chip  10  in various directions to enhance luminous efficacy of the light emitting module  500 . The reflective part  530  has a curved structure extending continuously along the inner side surface of the recess. Here, although the reflective part  530  is illustrated as having one curved structure, it should be understood that the disclosed technology is not limited thereto and the reflective part may include a plurality of reflective regions divided in the vertical direction. The reflective part  530  may include a highly reflective material coating. For example, Ag may be coated onto the reflective part  530 . In some implementations, Ag may be coated onto the entirety of the housing  520 . In some implementations, Ag may be coated onto the circuit board  110 . 
         [0142]    The bump  521  is placed near the reflective part  530 . The bump  521  protrudes in a ring shape along an edge of the recess on the upper surface of the housing. Although the bump  521  is illustrated as having a ring shape, it should be understood that the disclosed technology is not limited thereto and the bump  521  may be modified into various shapes including a polygonal shape depending upon the shape of the recess. 
         [0143]    The upper surface and the bump  521  contact the lens  550 . 
         [0144]    The lens  550  has a flat upper surface and a lower surface having a step structure  551  at an edge thereof. The shape of the lens  550  may vary depending upon the shape of the recess. The step structure  551  faces the upper surface of the housing  520  and the bump  521 . The step structure  551  can face-to-face contact the upper surface of the housing  520  and the bump  521 . The lens  550  may be formed of or include silicone, epoxy, glass or PMMA, without being limited thereto. Here, a bonding layer (not shown) may be interposed between the step structure  551  and the upper surface of the housing  520  and the bump  521 . The bonding layer (not shown) may be formed of or include an epoxy resin. The shape of the lower surface of the lens  550  may vary depending upon the shape of the recess. For example, the lens  550  may be or include a Fresnel. The Fresnel lens may have a plurality of patterns corresponding to the shape of the recess. For example, the plurality of patterns may have a circular structure corresponding to a circular structure of the recess. In some implementations, the plurality of patterns may have a different shape from the shape of the recess. For example, the plurality of patterns may have a quadrangular structure that is different from the circular structure of the recess. 
         [0145]    According to this exemplary embodiment, the housing  520  includes the reflective part  530  having the curved structure formed along the inner side surface of the recess to reflect light emitted from the light emitting diode chip  10  in various directions. Accordingly, the light emitting module  500  according to this exemplary embodiment can minimize internal light loss, thereby maximizing luminous efficacy. 
         [0146]    In addition, according to this exemplary embodiment, a contact area between the lens  550  and the housing  520  is increased by the lens  550  having the step structure  551 , thereby enhancing adhesion therebetween. Further, according to this exemplary embodiment, the lens  550  is aligned on the housing  520  by the step structure  551 , thereby minimizing an alignment error. 
         [0147]      FIG. 11  is a sectional view of a light emitting module according to a sixth exemplary embodiment of the disclosed technology. 
         [0148]    Referring to  FIG. 11 , a light emitting module  600  according to the sixth exemplary embodiment of the disclosed technology includes the same structure as that of the light emitting module  500  (see  FIG. 10 ) according to the fifth exemplary embodiment and includes different structure of a circuit board  610  from that of the light emitting module  500  for. The same components are indicated by the same reference numerals and detailed descriptions thereof are omitted. 
         [0149]    The circuit board  610  has a recess  611  formed on an upper surface thereof to receive light emitting diode chip  10 . The recess  611  includes an inclined inner side surface, which reflects light emitted from the light emitting diode chip  10 . The inner side surface of the recess  611  may extend from a reflective part  530  having a curved structure. The circuit board  610  may include a lead frame (not shown) or a conductive pattern (not shown), and may be a printed circuit board (PCB) or a ceramic substrate. Although the recess  611  is illustrated as extending from the reflective part  530  in this exemplary embodiment, the recess  611  may be separated a certain distance from the reflective part  530  in an inward direction. 
         [0150]    According to this exemplary embodiment, the light emitting module includes the housing  520 , which includes the reflective part  530  of the curved structure formed along the inner side surface of the recess, and the circuit board  610 , which has the recess  611  receiving the light emitting diode chip  100 , whereby light emitted from the light emitting diode chip  10  can be reflected along various paths. Accordingly, the light emitting module  600  according to this exemplary embodiment of the disclosed technology can minimize internal light loss, thereby maximizing luminous efficacy. 
         [0151]    In addition, according to this exemplary embodiment, a contact area between the lens  550  and the housing  520  is increased by the lens  550  having the step structure  551 , thereby enhancing adhesion therebetween. Further, according to this exemplary embodiment, the lens  550  is aligned on the housing  520  by the step structure  551 , thereby minimizing an alignment error. 
         [0152]      FIG. 12  is a sectional view of a light emitting module according to a seventh exemplary embodiment of the disclosed technology. 
         [0153]    Referring to  FIG. 12 , a light emitting module  700  according to the seventh exemplary embodiment includes a circuit board  110 , a light emitting diode package  710 , and a housing  620 . 
         [0154]    The light emitting diode package  710  includes a light emitting diode chip and a lens mounted on a substrate. The light emitting diode package  710  may have an upper luminous type. The light emitting diode chip may have a vertical type or a lateral type, without being limited thereto. The light emitting diode package  710  is mounted on the circuit board  110 . 
         [0155]    The housing  620  resides on the circuit board  110  and has a recess  625  formed at a central region thereof to receive the light emitting diode package  710 . Here, the circuit board  110  may include a lead frame (not shown) or a conductive pattern (not shown), and may be or include a printed circuit board or a ceramic substrate. The housing  620  includes a reflective part  630  formed on an inner side surface of the housing  620 . The reflective part  630  has a function of reflecting light emitted from the light emitting diode package  710  in various directions to enhance luminous efficacy of the light emitting module  700 . The reflective part  630  has a curved structure extending continuously along the inner side surface of the recess  625 . Here, although the reflective part  530  is illustrated as having one curved structure, it should be understood that the disclosed technology is not limited thereto and the reflective part may include a plurality of reflective regions divided along the vertical direction. The reflective part  630  may include a highly reflective material coating. For example, Ag may be coated onto the reflective part  630 . Ag may be coated onto the entirety of the housing  620  and may be coated onto the circuit board  110 . 
         [0156]    In the light emitting module according to this exemplary embodiment, the housing  620  includes the reflective part  630  having the curved structure formed along the inner side surface of the recess to reflect light emitted from the light emitting diode package  710  along various paths. Accordingly, the light emitting module  700  according to this exemplary embodiment can minimize internal light directions, thereby maximizing luminous efficacy. Although some exemplary embodiments have been described herein, it should be understood by those skilled in the art that these embodiments are given by way of illustration only and do not limit the scope of the disclosed technology. In addition, it should be understood that some features of a certain embodiment may also be applied to other embodiments without departing from the spirit and scope of the disclosed technology.