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You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a finishing panel attached to a surface of a wall, a floor or a door of a building structure, and more particularly to, a finishing panel which employs marble for exhibiting high grade atmosphere, and may be connected in a simple structure for improving construction workability and durability. 
         [0003]    2. Discussion of Related Art 
         [0004]    In general, ceramic tiles, steel plates or panels formed of reinforced plastics are widely used as wall or floor finishing elements. But recently, the interest in the residual environments such as apartments, public buildings or office spaces becomes growing, and there are increasing trends toward the use of panels formed of natural marble for producing differentiated and sophisticated atmosphere. 
         [0005]    For reference, commercial natural marble panels are produced and used with the standards of 600 mm×600 mm×20 mm, and 500 mm×500 mm×20 mm. However, the marble panels have disadvantages as described below. 
         [0006]    First, the cost of raw materials is a problem. The raw material cost of the marble itself is relatively high in comparison with other materials. Further, delivery or cutting of the marble cannot be carried out by general construction workers but carried out by stonemasons who are specially equipped and professionally skilled. Therefore, personnel expenses are very high and the high personnel expenses are included in the raw material cost, increasing the cost of the marble panels. Conclusionally, the marble panel cannot be used widely as a finishing element but is limitedly employed in partial buildings, which are very expensive. 
         [0007]    Second, characteristics of the materials are another problem. The marble is heavy and fragile in comparison with other materials. Therefore, the construction and handling thereof become difficult, increasing the construction cost thereof and extending a construction period thereof when constructing wall surfaces or floor surfaces with the marble panels. 
         [0008]    Therefore, demands for resolving the above problems of the marble panels are increasing. As a solution, there have been suggested a marble panel formed of a ceramic tile layer and a marble layer bound with each other by an adhesive agent, as disclosed in Korean Patent Publication No, 2003-90146 and Korean Patent Publication No. 2006-19824. In the disclosures, a commercial ceramic tile is used as a back body panel which substitutes a thickness of a pure marble panel. The ceramic tile is formed by sintering inorganic stone textured clay such as clay, feldspar, quartzite, quartz, and the like at a high temperature, which may achieve cost saving and weight reducing effects of the marble tiles to some degree. 
         [0009]    However, the ceramic tile has still problems in hardness that the ceramic tile is fragile so that the machining thereof such as cutting, milling, polishing, and the like is difficult. Conclusionally, the suggested ceramic tile attaching type marble panel has a limit that the complement of the fragile characteristics of a pure marble panel is impossible. Further, the weakness in the machining causes difficulties in proper adoption thereof for various construction environments and special designing or adoption thereof for improving the convenience of the constructions is impossible. 
       SUMMARY OF THE INVENTION 
       [0010]    Therefore, the present invention is derived to resolve the above and any other disadvantages of the prior art marble panels or marble tiles. 
         [0011]    According to the present invention, there is an object to provide a finishing panel to be attached to walls, floors, and doors of a building or any other structures, wherein the finishing panel uses marble. 
         [0012]    There is another object of the present invention to provide a finishing panel, which is superior in an economical aspect, simple in handling or construction, and exhibits high stability and high impact resistance especially. 
         [0013]    There is still another object of the present invention to provide a finishing panel, which may realize the convenience in the construction owing to superior machining characteristics and keep coupling states stably for a long time. 
         [0014]    In a finishing panel including a marble panel to be disposed at a front surface, and a back body panel joined with a rear surface of the marble panel, the back body panel includes a supporting panel formed in the same size with the marble panel and attached to the marble panel, and a coupling panel positioned at a rear surface of the supporting panel and having both sides facing each other and formed in corresponding shape with each other, wherein one of the sides is formed with a groove part behind the supporting panel, and the other one is formed with a protrusion part, so that the groove part and the protrusion part are engaged with a protrusion part and a groove part of other adjacent coupling panels. 
         [0015]    The groove part and the protrusion part are formed with holding elements for preventing separation thereof from each other when they are coupled with each other. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The objects, features and advantages of the present invention will be more clearly understood from the following detailed description in conjunction with the accompanying drawings, in which: 
           [0017]      FIG. 1  is a plan view showing a finishing panel according to a preferred embodiment of the present invention; 
           [0018]      FIG. 2  is a plan view of a finishing panel according to another preferred embodiment of the present invention, which is modified from the finishing panel of  FIG. 1 ; 
           [0019]      FIG. 3  is a plan view of a finishing panel according to a preferred embodiment of the present invention; 
           [0020]      FIG. 4  is an expanded cross-sectional view of a finishing panel according to the preferred embodiment of the present invention; and 
           [0021]      FIG. 5  is a cross-sectional view for explaining connection states of the finishing panel according to a preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0022]    Hereinafter, the supporting panel and the coupling panel are explained in detail in their material characteristics and the preferred embodiments according to the present invention will be described with reference to the accompanying drawings. 
         [0023]    The supporting panel is formed of materials such as gypsum plaster boards, bamlight boards, and acryl or fiber boards. 
         [0024]    In the gypsum board, gypsum plaster is cured in the stabilized crystallization state between two raw sheets for forming a strong board. 
         [0025]    Generally, the gypsum plaster board is superior in the properties such as fireproofness, lightweight, heat insulation, sound insulation, construction workability, waterproofness (waterproofness-processed gypsum), and the like, so that the gypsum plaster board is well-known as an ideal construction interior material. Therefore, the gypsum plaster board may be properly employed as a back body panel in the present invention. 
         [0026]    Further, the bamlight board represents so-called “fiber-reinforced cement plate” manufactured with cement and inorganic fibers as main raw materials. 
         [0027]    Generally, the bamlight board is superior in the properties such as incombustibility, lightweight, impact resistance, construction workability, anti-corrosiveness, and the like, so that the bamlight board is well-known not only as an incombustible interior material but also as an ideal finishing material in humid places. Therefore, the bamlight board may be properly employed as the back body panel in the present invention. In particular, the bamlight board may be formed in a multiply structure for improving waterproof properties in places of serious humidity. 
         [0028]    The acryl represents a plastic material formed of Methyl Methacrylate MMA as a main raw material. In general, the acryl board is superior in the properties such as light transmission, impact resistance, lightweight, chemical resistance, weather resistance, waterproofness, coloring power, and the like, so that the acryl board may be properly employed as the supporting panel in the present invention. Particularly, light passing through the marble panel may be diffused in the acryl, exhibiting illumination effect on the whole. 
         [0029]    The fiber board represents a plate element formed of plant fibers such as timber or straws by molding hot pressing or drying. The fiber boards are divided into soft fiber insulation boards, semihard fiber insulation boards (medium density fiber boards MDFs), hard fiber insulation boards (high density fiber boards HDFs) according to specific gravities thereof, wherein the MDFs or the HDFs is properly employed as the supporting panel in the present invention. 
         [0030]    Materials of the above supporting panels are superior in impact resistance and have no defects such as flexible deformation, bending, twisting, or crack according to humidity. Therefore, such the supporting panel complements fragile characteristics of the marble panel disposed at the front surface, and is simultaneously available as a first element of the back body panel for the marble panel without no deformation caused by environmental factors. Preferably, the supporting panel composing the back body panel and a coupling panel described below are coated with bio ceramic materials for antifungal and deodorizing effects. 
         [0031]    The fiber board is not essentially required for the coupling panel of the finishing panel in the present invention but may provide benefits as the finishing panel owing to their lightweight and high adhesiveness. Further, the fiber board is prepared relatively thickly and exhibits high machinery characteristics, so that the fiber board may be properly employed as a second element of the back body panel for the marble panel in the present invention. 
         [0032]    In the present invention, the finishing panel may be formed in various shapes for the convenience of construction. First, the finishing panels may be designed to be fitted with each other at side surfaces of other finishing panels, which are adjacent to each other. Second, the finishing panels may be fitted with rails, which are provided additionally. Structures thereof may be modified by the superior machining characteristics of the materials forming the back body panels of the present invention, which will be described in detail with respect to the accompanying drawings. 
         [0033]    Referring to  FIG. 1  and  FIG. 2 , a finishing panel  10  of the present invention includes a marble panel  11  disposed at a front surface position, and a back body panel  20  joined with a rear surface of the marble panel  11 . The back body panel  20  includes a supporting panel  23  formed of a gypsum plaster board, a bamlight board, an acryl or fiber board, and a coupling panel  24  positioned at a rear part of the supporting panel  23  for keeping coupling states between such the finishing panels  10 . The supporting panel  23  is formed with a surface area equal with that of the marble panel  11 , and the coupling panel  24  is joined with a rear part of the supporting panel  23 , wherein the coupling panel  24  is inclined in a diagonal direction as shown in  FIG. 1  or in a lateral direction as shown in  FIG. 2  with respect to the marble panel  11 . 
         [0034]    In the structure as described above, the adjacent finishing panels  10  may be fitted with each other like puzzle pieces. Even though it is not shown, the puzzle type fitting structure may be employed for back body panels  20  which include fiber boards as the coupling panels. 
         [0035]    At this time, the back body panel  20  is entirely inclined or the coupling panel  24  of the back body panel  20  may be inclined. 
         [0036]    Referring to  FIG. 3  and  FIG. 4 , the finishing panel  10  of the present invention includes a marble panel  11  disposed to a front surface position, and a back body panel  20  joined with a rear surface of the marble panel  11 . The back body panel  20  includes a supporting panel  23  formed of a gypsum plaster board, a bamlight board, or an acryl board, and a coupling panel  24  formed of a fiber board. The supporting panel  23  is formed in the standards equal with those of the marble panel  11 , and joined with the marble panel  11  concentrically. 
         [0037]    On the other hand, the coupling panel  24  is in the shape with corresponding upper and lower sides, and corresponding right and left sides, wherein the corresponding sides respectively face each other with respect to the marble panel  11 . That is, the coupling panel  24  has a side formed with a groove part  25  behind the supporting panel  23  and the other side formed with a protrusion part  26  at a position corresponding to the groove part  25 . Therefore, the coupling panels  24  are engaged with each other by the fitting of the protrusion part  25  of a coupling panel  24  into the groove part  25  of another coupling panel  24 . For the convenience of assembling, the protrusion part  26  is formed in a tapered shape which is inclined gradually toward a tip thereof. 
         [0038]    In order to reinforce the coupling force in the engagement between the groove part  25  and the protrusion part  26 , holding elements are provided for preventing deviation of the groove part  25  and the protrusion part  26  from the engagement state therebetween. 
         [0039]    Referring to  FIG. 4 , as for the holding elements, the groove part  25  is formed with a holding groove  27  and the protrusion part  26  is formed with a holding protrusion  28  in the complementary shape with the holding groove  27  at a position corresponding to the holding groove  27 . 
         [0040]    As describe above, the groove part  25  and the protrusion part  26  in the complementary shape, and the coupling structure provided by the holding groove  27  and the holding protrusion  28 , which makes the groove part  26  and the protrusion part  26  engaged and prevents the engagement between the groove part  26  and the protrusion part  26 , realize coupling between the finishing panel  10  and other adjacent finishing panels  10  in the fitting manner. 
         [0041]    In the meantime, the coupling panel  24  of the back body panel  20  has rail grooves  33  to be fitted into rails, which are provided additionally to a surface of a structure. In the construction, the finishing panels  10  may be attached to the structure by fitting the coupling panels  24  to the rails, wherein the finishing panels  10  may be naturally disposed in position. 
         [0042]    The rail structures  33  may be employed without any relationship with the groove part  25  and the protrusion part  26 , which are complementary with each other, and the structure of the holding groove  27  and the holding protrusion  28  for preventing the deviation of the groove part  25  and the protrusion part  26  from each other, but may be employed together with the above structures simultaneously for realizing much improved convenience in the construction. 
         [0043]    The finishing panel according to the present invention includes a front marble panel and a back body panel joined with a rear surface of the marble panel. The back body panel is selectively formed of materials having high impact resistance, superior construction workability and superior machining characteristics. Therefore, the back body panel complements the fragile characteristics of the marble panel. 
         [0044]    In the meantime, a groove part and a protrusion part in the complementary shape, and a deviation-preventing coupling structure, that is, a holding groove and a holding protrusion respectively formed at the groove part and the protrusion part, keep the coupling state between the finishing panels stably. 
         [0045]    Therefore, the finishing panel of the present invention may provide construction convenience and keep stable construction states for a long time, thereby improving competitiveness and reliability. 
         [0046]    Although the foregoing description has been made with reference to the preferred embodiments, it is to be understood that changes and modifications of the present invention may be made by the ordinary skilled in the art without departing from the spirit and scope of the present invention and appended claims.

Summary:
A finishing panel using marble including a marble panel to be disposed at a front surface and a back body panel joined with a rear surface of the marble panel, wherein the back body panel comprises a supporting panel formed in the same size with the marble panel and attached to the marble panel, and a coupling panel positioned at a rear surface of the supporting panel and having both sides facing each other in complementary shape, and wherein one of the sides is formed with a groove part behind the supporting panel, and the other side is formed with a protrusion part, so that the groove part and the protrusion part of the coupling panel are engaged with a protrusion part and a groove part of adjacent coupling panels.