Abstract:
The present invention relates to a lighting device enabling arbitrary distribution of light, which includes: a hollow receptacle having a cover to be opened or closed; a pivot part mounted in a fixing hole provided in the bottom of the receptacle so as to be tilted and pivoted; a light module part connected through an adjustment shaft to the pivot part, the light module part being tilted and pivoted by the pivot part so as to control the distribution of light; and a fixing part for adjusting the pivot part to be fixed or to be tilted and pivoted. The present invention enables a plurality of light modules to be separately adjusted to control the distribution of light, and provides fixing means for fixing the positions of the light modules thus adjusted, so that the distribution of light may be controlled regardless of the installed position of the lighting device, thereby preventing light from penetrating into surrounding buildings.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of International Application No. PCT/KR2013/001383 filed on Feb. 21, 2013, which claims a priority to Korean Patent Application No. 10-2012-0018348 filed on Feb. 23, 2012 and Korean Patent Application No. 10-2013-0010767 filed on Jan. 31, 2013, which applications are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to a lighting device enabling arbitrary light distribution, and more particularly, to a lighting device enabling arbitrary light distribution, which can freely adjust light distribution of an individual light. 
       BACKGROUND ART 
       [0003]    Recently, the Ministry of Environment in Korea has declared a “law for preventing light pollution generated by artificial lighting”. This law will be enforced from Feb. 1, 2013. The main contents are to protect national health from abusement of the artificial lighting, to prevent harm affecting an ecosystem, and to manage excessive light and intrusive light by determining an acceptable light radiation standard of building lighting, an electronic sign, and lighting of various infrastructures. 
         [0004]    At night, in order to prevent generation of the intrusive light which indicates that beams of light of city infrastructure lighting, building lighting, and electronic signs intrude into surrounding buildings, street lights and other lights should follow a light reflection acceptance standard, and light distribution which indicates directions of light radiation should be adjusted. 
         [0005]    The light distribution using a Light Emitting Diode (LED) according to the related art relates to a structure of enlarging light distribution of a lighting module as in Patent Laid-Open Publication No. 10-2011-0108269, or relates to a method of adjusting light distribution using a lens as in Patent Registration No. 10-0961676. 
         [0006]    However, the structures for enlarging light distribution of a lighting module have a problem in that light pollution is increased by increasing penetration light according to an increase in a light distribution area thereof. Further, the technologies for adjusting light distribution using a lens have problems in that an optical efficiency may be reduced by use of a lens, a proper lens should be replaced as needed, and a proper lens corresponding to each of the lights should be made. 
       SUMMARY 
       [0007]    The present invention is conceived to solve the aforementioned problems, and an aspect of the present invention is to provide a lighting device enabling arbitrary light distribution, which can arbitrarily adjust light distribution according to a surrounding environment. 
         [0008]    In order to solve the aforementioned problems, a lighting device enabling arbitrary light distribution is provided. The lighting device includes: one or more fixing holes provided on a fastening plate; a rotational portion inserted into the fixing hole to be tilted and rotated; and an optical module portion coupled to the rotational portion, light distribution of the optical module portion being adjusted according to the tilting and the rotating of the rotational portion. 
         [0009]    A lighting device enabling arbitrary light distribution according to the present invention has effects that light distribution of a plurality of optical modules can be individually adjusted, a fixing means for fixing a location of an optical module, light distribution of which has been adjusted, is provided so as to arbitrarily adjust light distribution regardless of an installation location, and penetration light penetrated into surrounding buildings is not generated. 
         [0010]    That is, the lighting device enabling arbitrary light distribution according to the present invention has effects that an installer can arbitrarily adjust light distribution, and an area where lighting is needed and an area where lighting is not needed are separately illuminated, thereby preventing generation of light pollution. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is an exploded perspective view illustrating a lighting device enabling arbitrary light distribution according to an exemplary embodiment of the present invention; 
           [0012]      FIG. 2  is a sectional view illustrating a part of a coupling state of a lighting device enabling arbitrary light distribution according to an exemplary embodiment of the present invention; 
           [0013]      FIG. 3  is a bottom view illustrating a lighting device enabling arbitrary light distribution according to an exemplary embodiment of the present invention, of which arbitrary light distribution has been adjusted through the aforementioned adjustment of light distribution; 
           [0014]      FIGS. 4 to 6  are sectional views illustrating parts of lighting devices enabling arbitrary light distribution according to other embodiments of the present invention; 
           [0015]      FIG. 7  illustrates a configuration of a lighting device enabling arbitrary light distribution according to another embodiment of the present invention; 
           [0016]      FIG. 8  is a side sectional view of  FIG. 7 ; 
           [0017]      FIG. 9  is an exploded perspective view illustrating a first rotational portion and a second rotational portion which are rotation portions of  FIG. 7 ; 
           [0018]      FIG. 10  is a bottom view illustrating the first rotational portion of  FIG. 9 ; 
           [0019]      FIG. 11  is a side view illustrating the first rotational portion of  FIG. 9 ; 
           [0020]      FIG. 12  is a bottom view illustrating the second rotational portion of  FIG. 9 ; 
           [0021]      FIG. 13  illustrates a configuration of a rotation restraint portion applied to an embodiment of the present invention; 
           [0022]      FIG. 14  illustrates a configuration of a rotation restraint portion applied to another embodiment of the present invention; and 
           [0023]      FIG. 15  is a sectional view taken along line A-A of  FIG. 14 . 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Hereinafter, a lighting device enabling arbitrary light distribution according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings. 
         [0025]      FIG. 1  is an exploded perspective view illustrating a lighting device enabling arbitrary light distribution according to an exemplary embodiment of the present invention. 
         [0026]    Referring to  FIG. 1 , the lighting device enabling arbitrary light distribution according to an exemplary embodiment of the present invention includes a housing  10  provided with an upper cover  11 , a plurality of optical module portions  20  disposed at a lower side of the housing  10 , a rotational portion  30  for rotatably and tiltably fixing the optical module portion  20  to a bottom portion  12  of the housing  10 , an adjustment shaft portion  40  for connecting the rotational portion  30  and the optical module portion  20  to each other to rotate and tilt the optical module portion  20  according to the rotating of the rotational portion  30 , a fixing portion  50  for fixing the rotational portion  30  in a state in which light distribution of the optical module portion  20  is adjusted by the rotating and the tilting of the rotational portion  30 . 
         [0027]    The non-described reference numeral  19  corresponds to a sealing portion located between the housing  10  and the upper cover  11 . 
         [0028]    The upper cover  11  is hinge-coupled to a side portion of the housing to be openable, a fixing hole  13  into which a part of a lower portion of the spherical rotational portion  30  is inserted is provided on the bottom portion  12  of the housing  10 . 
         [0029]    The diameter of the rotational portion  30  is larger than that of the fixing hole  13 , so that the rotational portion  30  can prevent the fixing hole  13  from being separated from the outside of the housing  10 , which corresponds to a lower side thereof. 
         [0030]      FIG. 2  is a sectional view illustrating a part of a lighting device enabling arbitrary light distribution according to an exemplary embodiment of the present invention. 
         [0031]    As illustrated, a connection portion connected to the rotational portion  30 , i.e. an edge of the fixing hole  13 , supports the lower side of the rotational portion  30  and has a curved surface of which the upper side is wider such that the rotational portion  30  can be rotated and tilted. 
         [0032]    Further, the bottom surface  12  adjacent to the fixing hole  13  has a coupling groove  14  formed lower than the other area of the bottom surface  12 , and screw threads are provided at the inner side of the coupling groove  14  so that the fixing portion  50  is disconnected from or connected to the rotational portion  30  while being upwardly or downwardly moved along a rotational direction. 
         [0033]    The aforementioned form of the coupling groove  14  may be modified in various forms, and the fixing portion  50  may be also modified in various forms according to the modified examples. The aforementioned other examples will be described in more detail afterward. 
         [0034]    The shape of the bottom surface of the coupling groove  14  has a sloped surface  15  sloped such that the diameter thereof is widened as it goes from the bottom surface of the fixing hole  13  to the outside to be suitable for limiting the tilting angle of the optical module portion  20 . 
         [0035]    In this structure, an operator installs the housing  10 , opens the upper cover  11 , unfastens the fixing portion  50 , and then allows the rotational portion  30  to be tilted and rotated. 
         [0036]    As illustrated in  FIG. 2 , the adjustment shaft portion  40  vertically passes through the rotational portion  30 , the lower side of the adjustment shaft  40  is connected to the optical module portion  20 , and the upper side of the adjustment shaft portion  40  is exposed to the upper side of the rotational portion  30 , and is located within the housing  10 . 
         [0037]    The upper side of the adjustment shaft portion  40  is manipulated by a hand to tilt and rotate the optical module portion  20  so as to adjust light distribution of the optical module portion  20 . 
         [0038]    In addition, the adjustment shaft portion  40  can be automatically manipulated by using a driving means such as a motor, a control line for controlling the driving means can be extend to the outside. Such an automatic control scheme may be modified in various forms by those skilled in the art, and the configuration for the automatic control belongs to the present invention as long as another structure of the present invention is employed equally or similarly. 
         [0039]    When the light distribution of the optical module portion  20  is adjusted by rotating or tilting the rotational portion  30 , the lower portion of the adjustment shaft portion  40  can be tilted only in an area limited by the sloped surface  15 . Such a limiting of the tilting is configured for preventing the light distributions of the plurality of optical module portions  20  from overlapping each other. 
         [0040]    However, as in another embodiment of the present invention which will be described below, the light distributions of the optical module portions  20  may be allowed to overlap each other, and at this time, the sloped surface  15  does not exist. 
         [0041]    In this way, after the light distribution of one optical module portion  20  is adjusted, the fixing portion  50  is rotated and locked, thereby fixing the rotational portion  30  not to be rotated or tilted any more. 
         [0042]    The fixing portion  50  may have a configuration in which an insertion fastening portion  51  inserted into the coupling groove  14  and having a screw structure engaged with the screw threads of the coupling groove  14  and formed at the outer peripheral surface thereof, a body  55  protruding toward the upper side of the insertion fastening portion  51  and having a sloped surface of which the step is lowered as the upper surface thereof goes toward the central side, and a handle portion  52  coupled to both ends of the outer diameter portion of the body  55  and extending upwardly so as to enable an operator to easily rotate the optical module portion  20  by his/her hand, are integrally provided. 
         [0043]    That is, the fixing portion  50  enables an operator to perform unfastening or locking with his/her hand and even without a separate tool, thereby easily performing an adjustment operation of light distribution. 
         [0044]    A lower locking step  53  having a lower surface protruding circularly at a location spaced apart from the rotational portion  30  from a predetermined distance is provided on the bottom surface of the insertion fastening portion  51 , and an O-ring  54  is located between the lower locking step  53  and the rotational portion  30 . 
         [0045]    It is preferred that the inner diameter of the O-ring  54  is smaller than the maximum diameter of the spherical rotational portion  30 , thereby providing a waterproof effect, and serving to firmly fix the rotational portion  30  when the fixing portion  50  is locked. Further, the O-ring  54  is made of a general flexible material, and is laterally spread and pressed when the fixing portion  50  is pressed to be locked, thereby improving the waterproof effect thereof. The O-ring  54  serves to smoothly rotate the rotational portion  30  in a state in which the fixing portion  50  is unfastened. 
         [0046]    The optical module portion  20  includes a housing  21  having a hollow interior having a bell-shaped sectional surface, a toroidal substrate  22  provided at an inner upper portion of the housing  21 , and a Light Emitting Diode (LED)  23  fixed to the bottom surface of the substrate  22  and installed such that a light emitting surface thereof faces a lower side. 
         [0047]    Such a structure of the optical module portion  20  has a general form of an optical module using an LED  23 , and the present invention is not limited to such a detailed form of the optical module portion  20 , and may be modified in various forms. For example, the optical module portion  20  according to the present invention is not limited by the size or the slope angle of the inner surface of the housing  21 . 
         [0048]    It is preferred that the adjustment shaft portion  40  connected to the optical module portion  20  in order to supply electric power to the substrate  22  has a hollow shape such that an electric wire (not illustrated) may be inserted thereinto, and a withdrawal hole  41  may be provided at a part of the upper portion of the adjustment shaft portion  40  such that the electric wire may be connected to an electric wire of the outside of the housing  10  by being interconnected to the interior of the housing  10 . The housing  10  has an external coupling portion  16  provided at one side thereof and capable of being coupled and fixed to a support (not illustrated), and the electric wire of the outside can be connected to the housing  10  through the external coupling portion  16 . 
         [0049]    At this time, the withdrawal hole  41  has a slit shape, thereby preventing disconnection of the electric wire caused by moving of the adjustment shaft portion  40 , and preventing the tilting and the rotating of the adjustment shaft portion  40  from being limited by the electric wire. 
         [0050]      FIG. 3  is a bottom view illustrating a lighting device enabling arbitrary light distribution according to an embodiment of the present invention, of which arbitrary light distribution has been adjusted through the aforementioned adjustment of light distribution. 
         [0051]    Referring to  FIG. 3 , the present invention can manually or automatically adjust light distribution of each of the plurality of the optical module portions  20 , and can accurately adjust light distribution by separately illuminating an area where lighting is needed and an area where lighting is not needed. 
         [0052]    Therefore, the light pollution can be prevented from being caused by radiating unnecessary light to the area where the lighting is not needed, such as an interior of a building, a field, a rice paddy, an orchard, etc. 
         [0053]      FIG. 4  is a sectional view illustrating a part of a lighting device enabling arbitrary light distribution according to another embodiment of the present invention. 
         [0054]    Referring to  FIG. 4 , the lighting device enabling arbitrary light distribution according to another embodiment of the present invention has a structure in which a bottom portion  12  around a fixing hole  13  of a housing  10  has a flat structure, and a coupling portion  18  having a circular sectional surface protrudes around the fixing hole  13  of the bottom portion  12 . 
         [0055]    Screw threads are provided on the cylindrical inner surface of the coupling portion  18  so as to be rotation-coupled to an insertion fastening portion  51  of a fixing portion as described above, and the rotational portion  30  can be adjusted either in a tillable and rotatable state or in an untiltable and unrotatable state by manipulating a handle  52  of the fixing portion  50 . 
         [0056]    At this time, since a surrounding portion of the adjustment shaft portion  40  for connecting the rotational portion  30  and the optical module portion  20  does not have the slope surface  10  on the bottom surface of the coupling groove  14  in the embodiment described with reference to  FIG. 2 , a tilting angle is not limited and can be adjusted to the maximum tilting angle. 
         [0057]    Such a structure implies that the light distribution according to the present invention can be performed excessively, so that the light distribution of the lighting device according to the present invention can be freely adjusted while not being limited by an installation angle of the housing  10 . 
         [0058]      FIG. 5  is a sectional view illustrating a part according to another embodiment of the present invention. 
         [0059]    Referring to  FIG. 5 , the adjustment shaft portion  40  according to the present invention may have a structure of connecting the rotational portion  30  and the optical module portion  20  to each other and not protruding toward the upper side of the rotational portion  30 , differing from the configuration of  FIG. 2  of protruding and extending toward the upper side of the rotational portion  30 . 
         [0060]    At this time, an uneven pattern portion  31  is provided at a part of the upper portion of the rotational portion  30  to easily tilt and rotate the rotational portion  30 , and an operator can tilt and rotate the rotational portion  30  by allowing his/her finger to be in contact with the uneven pattern portion  31  and rubbing the uneven pattern portion  31 . 
         [0061]    Such a structure is to more thinly manufacture the thickness of the housing  10  thinner. 
         [0062]      FIG. 6  is a sectional view illustrating a part according to another embodiment of the present invention. 
         [0063]    Referring to  FIG. 6 , the present invention can employ a bolt-type fixing portion  60  in addition to the fixing portion  50  illustrated in  FIG. 2 , in order to adjust the rotational portion  30  in a tiltable and rotatable state or an untiltable and unrotatable state. 
         [0064]    At this time, a coupling portion  61  having a form similar to the coupling portion of  FIG. 4  is provided, but the coupling portion  61  does not have screw threads formed at the inner diameter side thereof, has screw holes at a lateral side thereof, and can fix the rotational portion  30  or make the rotational portion  30  be in a tiltable and rotatable state by adjusting an adjustment bolt  62  inserted into the screw holes. 
         [0065]      FIG. 7  illustrates a configuration of a lighting device enabling arbitrary light distribution according to another embodiment of the present invention, and  FIG. 8  is a side sectional view of  FIG. 7 . 
         [0066]    Referring to each of  FIGS. 7 and 8 , the lighting device enabling arbitrary light distribution according to another embodiment of the present invention includes a first rotational portion  100  having an upper portion inserted into a fixing hole provided at a fastening plate  17  and capable of rotating in a direction parallel to the fastening plate  17 , a nut  150  being fastened to the upper portion of the fastening plate  17 ; a second rotational portion  200  rotatably coupled to the lower end of the first rotational portion  100  and capable of rotating in a direction perpendicular to the fastening plate  17 , the optical module portion  20  being fixed to the lower end thereof; and an electric wire  300  connected to the optical module portion  20  from the upper portion of the fastening plate  17  through the interiors of the first rotational portion  100  and the second rotational portion  200  to supply electric power. 
         [0067]    The first rotational portion  100  and the second rotational portion  200  have the same effect as that of the rotational portion  30  according to the aforementioned embodiment, and the first rotational portion  100  and the second rotational portion  200  refer to a rotational portion. 
         [0068]    Hereinafter, a configuration and an effect of the lighting device enabling arbitrary light distribution according to another embodiment of the present invention will be described in more detail. 
         [0069]    First, the fastening plate  17  serves as a support member for supporting the optical module portion  20  to rotate the optical module portion by the first rotational portion  100  and the second rotational portion  200 , and the number of the fixing holes is equal to the installation number of the optical module portions  20 . 
         [0070]    The fastening plate  17  corresponds to the bottom portion  12  of the housing  10  in the aforementioned embodiment, but needs not be installed on the bottom portion  12  of the housing  10  and can be installed when the fastening plate  17  is a plate-shaped structure. 
         [0071]      FIG. 9  is an exploded perspective view illustrating the rotational portion,  FIG. 10  is a bottom view illustrating the first rotational portion  100 ,  FIG. 11  is a side view illustrating the first rotational portion  100 , and  FIG. 12  is a bottom view illustrating the second rotational portion  200 . 
         [0072]    Hereinafter, a configuration and an effect of each portion will be described in more detail with reference to  FIGS. 9 to 12 . 
         [0073]    First, the first rotational portion  100  includes an insertion tube portion  110  inserted into the fixing hole of the fastening plate  17 , a rotational plate  120  provided at a circular-arc-shaped first guide groove  121  to identify a rotation degree and having a first gradation portion  122  formed at the bottom surface thereof, and a connection portion  130  downwardly protruding from the bottom surface of the rotational plate  120  and enabling the second rotational portion  200  to be rotatably fastened. 
         [0074]    The second rotational portion  200  includes a rotation connection portion  210  coupled to the lateral surface of the connection portion  130  in a rotatable state or a fixed state according to a turning degree of a fixing screw  140 , and a fixing plate  220  for fixing the rotation connection portion  20  to the optical module portion  20 . 
         [0075]    The fastening protrusion portion  212  protrudes at a rotational center of the rotation connection portion  210 , and is coupled to the fixing screw  140  while being inserted into a fastening hole  131  of the connection portion  130 . 
         [0076]    At this time, in a state in which the fixing screw  140  is loosely coupled, the rotation connection portion  210  can rotate in a direction perpendicular to the fastening plate  17 , and can rotate the optical module portion  20  fixed by the fixing plate  220  at the lower side thereof. 
         [0077]    The electric wire  300  is inserted through the insertion tube portion  110 , is introduced into a second guide groove  211  of the second rotational portion  200  through a guide protrusion portion  132  provided at the connection portion  130 , and is finally connected to the optical module portion  20  through a through-hole  222  so as to supply electric power to the optical module portion  20 . 
         [0078]    The insertion tube portion  110  of the first rotational portion  100  is inserted through the fixing hole of the fastening plate  17  from the lower side to the upper side, has a fastening screw provided at the outside thereof, and has a tubular inner surface such that the electric wire  300  is inserted thereinto. The insertion tube portion  110  protruding toward the upper side of the fastening plate  17  is fixed to the nut  150 . At this time, the nut  150  is not to fix the first rotational portion  100  to the fastening plate  17  in a completely close contact state but to maintain a state in which the first rotational portion  100  is fastened to the fastening plate  17 . Thereafter, a bolt  160  is firmly coupled and fixed to the bottom surface of the fastening plate  170  through the first guide groove  121  in an unrotatable state. 
         [0079]    The rotational plate  120  has a diameter larger than that of the insertion tube portion  110 , and can horizontally rotate about the fastening plate  17  together with the insertion tube portion  110 . A circular-arc-shaped first guide groove  121  is provided configuring the insertion tube portion  110  as a center thereof. 
         [0080]    The first guide groove  121  may have a semicircular arc shape of 180 degrees, so as to rotate by 180 degrees in a state in which the bolt  160  fastened to the first guide groove  121  is loosely coupled. In this way, even when the first guide groove  121  rotates by 180 degrees, the second rotational portion  200  can rotate about the fastening plate  17  in a vertical direction, so that the optical module portion  20  coupled to the lower portion of the second rotational portion  200  is substantially in a state of being capable of rotating about the fastening plate  17  by 180 degrees in a horizontal direction. 
         [0081]    The first gradation portion  122  is located on the bottom surface of the rotational plate  120  between edges of the first guide groove  121  and the rotational plate  120 , thereby identifying a rotation degree of the rotational plate  120 . 
         [0082]    The rotation degree of the rotational plate  120  uses a location of the bolt  160  as a reference point, and a first indicator  161  protruding toward the first gradation portion  122  at one side of the bolt  160  is provided, thereby identifying an accurate gradation. 
         [0083]    The connection portion  130  downwardly protrudes from a bottom central portion of the rotational plate  120 , and the shape of the bottom surface thereof has a semispherical shape. 
         [0084]    The connection portion  130  is fixed by the fixing screw while being in contact with the rotation connection portion  210  of the second rotational portion  200 , and the second rotational portion  200  can be adjusted either in a rotatable state or in an unrotatable state according to a turning degree of the fixing screw  140 . 
         [0085]    To this end, the connection portion  130  has a fastening hole  131  provided at a rotational center of the rotation connection portion  210 , and the rotation connection portion  210  has a fastening protrusion portion  212  inserted into the fastening hole  131 . The fixing screw is coupled to the fastening protrusion portion  212  inserted into the fastening hole  131  at one side of the fastening hole  131 . 
         [0086]    The rotation connection portion  210  can rotate about the fastening protrusion portion  212  in a direction perpendicular to the fastening plate  17 , and at this time, a circular-arc-shaped second guide groove  211  is provided to configure the fastening protrusion portion  212  as a center thereof in order to guide the rotation. 
         [0087]    The second guide groove  211  serves as a channel for connecting the electric wire  300  as well as to guide the rotation. The guide protrusion portion  132  protruding from the connection portion  130  is inserted into the second guide groove  211 , so as to perform stable rotation. 
         [0088]    The guide protrusion portion  132  is configured to have a cylindrical structure of which the center is empty and to be connected to the optical module portion  20  through the second guide groove  211  by withdrawing the electric wire  300  inserted through the insertion tube portion  110 . 
         [0089]    Further, a second gradation portion  133  is provided at the connection portion  130  in order to identify a rotation degree of the rotation connection portion  210 . The second gradation portion  133  is located on a surface opposite to one side of the connection portion  310  contacting the rotation connection portion  210 . 
         [0090]    In order to accurately determine a rotation degree of the rotation connection portion  210 , a second indicator  215  is provided at the lower side of the fastening protrusion portion  212  of the rotation connection portion  210 . 
         [0091]    In this state, it is easy to identify the rotation degree in a perpendicular direction of the fastening plate  17  of the optical module portion  20  which rotates together with the second rotation portion  200  including the rotation connection portion  210 . 
         [0092]    The optical module portion  20  is generally provided with a housing including a heat dissipation plate, so that it is difficult to maintain a light radiation angle only by using a simple fastening structure. That is, an initially-installed angle may be displaced by effects of wind or gravity. An insertion groove  213  is provided between the fastening protrusion portion  212  of the rotation connection portion  210  and the second indicator  215  in order to prevent this phenomenon, and a rotation restraint portion  214  is inserted and fixed to the insertion groove  213 . 
         [0093]    The rotation restraint portion  214  increases a friction force between the connection portion  130  and the rotation connection portion  210  when the fixing screw  140  is fastened, thereby preventing the rotation connection portion  210  from being rotated by wind or gravity. Such a detailed configuration of the rotation restraint portion  214  will be described in more detail below. 
         [0094]    A fixing plate  220  is provided at the lower portion of the rotation restraint portion  241 , and fixes the optical module portion  20  on the bottom surface of the fixing plate  220  by inserting a coupling means such as a bolt into a fixing hole  221 . 
         [0095]    A through-hole  222  communicating with the second guide groove  211  is located on the bottom surface of the fixing plate  220 , so that the electric wire  100  is connected to the optical module portion  20 . The through-hole  222  may be exposed by a sloped surface  225  extending to the bottom surface of the fixing plate  220 . 
         [0096]    Drainage channels  223  and  224  for connecting a part and an edge of the through-hole  222  are provided on the bottom surface of the fixing plate  220 . The drainage channels  223  and  224  are configured to prevent an electric short state from being generated in the optical module portion  20  to which the electric wire  300  is connected, by rainwater which may flow therein by any chance. 
         [0097]    Since the connection portion  130  and the rotation connection portion  210  are substantially in close contact with each other, it is determined that rainwater does not flow therein. However, in order to prepare for a case where rainwater flows therein through the second guide groove  211  of the rotation connection portion  310  by any chance, it is preferred that the drainage channels  223  and  224  are formed to discharge the rainwater. 
         [0098]      FIG. 13  illustrates the rotation restraint portion  214  according to an embodiment of the present invention. 
         [0099]    Referring to  FIG. 13 , the rotation restraint portion  214  has a plate-shaped structure in which first and second bent portions  214 - 1  and  214 - 2  are provided at central portions of both ends facing a rotational direction of the rotation connection portion  210 . At this time, the first bent portion  214 - 1  and the second bent portion  214 - 2  are bent toward opposite directions, respectively. This configuration prevents the second rotation portion  200 , to which the optical module portion  20  is coupled, from being rotated by wind or gravity, by pressing the first bent portion  214 - 1  and the second bent portion  214 - 2  according to the fastening of the coupling screw  140  and increasing a frictional force between the connection portion  130  and the rotation connection portion  210  by restoration forces of the first bent portion  214 - 1  and the second bent portion  214 - 2 . 
         [0100]      FIG. 14  illustrates the rotation restraint portion  214  according to another embodiment of the present invention, and  FIG. 15  is a sectional view taken along line A-A of  FIG. 14 . 
         [0101]    Referring to  FIGS. 14 and 15 , the rotation restraint portion  214  according to another embodiment has a plate-shaped structure, and is configured by third bent portions  214 - 3  obtained by cutting a part of the plate and bending the cut part upward and fourth bent portions  214 - 4  obtained by cutting a part of the plate and bending the cut part downward. 
         [0102]    Such a structure can make the coupling between the connection portion  130  and the rotation connection portion  210  firmer due to the third bent portions  214 - 3  and the fourth bent portions  214 - 4 , thereby preventing the second rotational portion  200  including the rotation connection portion  210  from being rotated by wind or gravity. 
         [0103]    Using such a configuration, the lighting device enabling arbitrary light distribution according to another embodiment of the present invention can rotate the optical module portion  20  in all directions, so as to be installed to have individual light distribution matched with surrounding environment conditions of installation locations of lights. 
         [0104]    It will be obvious to those skilled in the art to which the present invention pertains that the prevent invention is not limited to the aforementioned embodiment, and may be modified and varied without departing from a technical subject matter of the present invention. 
         [0105]    The present invention has industrial applicability since, in the lighting device including a plurality of lighting modules, light distribution for each of lights can be adjusted so as to illuminate only an area where lighting is needed.