Patent Publication Number: US-9414503-B2

Title: Multi-display device

Description:
This application claims the benefit of Korean Patent Application Nos. 10-2012-0102397 filed on Sep. 14, 2012, 10-2012-0102394 filed on Sep. 14, 2012; and 10-2012-0102393 filed on Sep. 14, 2012, the entire contents of which are incorporated herein by reference for all purposes as if fully set forth herein. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Embodiments of the invention relate to a multi-display device. 
     2. Discussion of the Related Art 
     A multi-display device may be manufactured by disposing a plurality of display modules to be adjacent to one another. 
     The multi-display device may implement the large-sized screen using the small-sized display modules. 
     SUMMARY OF THE INVENTION 
     In one aspect, there is a multi-display device including a main frame, a plurality of module supporters disposed on the main frame, a plurality of display modules which are hung on the plurality of module supporters, each of the plurality of display modules including a display panel, and a spacer positioned between the two adjacent display modules, wherein the spacer includes a base plate extending in a width direction of the display modules, a first protrusion extending from a first surface of the base plate, and a second protrusion extending from a second surface opposite the first surface of the base plate, wherein the base plate includes a portion which protrudes further than the two adjacent display modules in the width direction of the display modules. 
     The first protrusion has spirals, wherein a diameter of the first protrusion is greater than a diameter of the second protrusion, wherein a length of the second protrusion is equal to or greater than a length of the first protrusion. 
     A surface roughness of a third surface adjacent to the first and second surfaces of the base plate is greater than a surface roughness of the first and second surfaces of the base plate. 
     Each of first and second display modules, which are adjacent to each other, has a hole, wherein the first protrusion is inserted into the hole of the first display module, and the second protrusion is inserted into the hole of the second display module. 
     Each of the first and second display modules includes: the display panel; a frame attached to a back surface of the display panel; a back cover positioned in the rear of the frame; and a structure positioned between the frame and the back cover, the structure having a hole. 
     A diameter of the base plate in the width direction of the display modules is greater than a width of the structure in the width direction of the display modules. 
     The base plate includes a portion, which protrudes further than the structure to the backward at a boundary of the first and second display modules in the width direction of the display modules. 
     The multi-display device further includes a substrate positioned in the front of the display module; and a side cover which is positioned on the side of the display module and the side of the substrate and is connected to the display module and the substrate. 
     The side cover includes an outer cover and an inner cover positioned between the outer cover and the substrate, wherein elasticity of the inner cover is greater than elasticity of the outer cover. 
     The outer cover includes a first hole for fastening the outer cover to the display module and a first rail corresponding to the substrate, wherein the inner cover includes a second rail positioned on the first rail, wherein an end of the substrate is inserted into the second rail. 
     A length of the inner cover is less than a length of the outer cover. 
     The display module includes: the display panel; a frame attached to a back surface of the display panel; a back cover positioned in the rear of the frame; and a structure which is positioned between the frame and the back cover and connects the frame to the back cover, the structure having a second hole corresponding to the first hole of the outer cover. 
     The plurality of substrates are inserted into the second rail of at least one of the plurality of inner covers. 
     The number of substrates is equal to or less than the number of display modules. 
     The plurality of module supporters include: at least one horizontal portion connected to the main frame in a horizontal direction; and at least one vertical portion which is hung on the horizontal portion in a vertical direction. 
     The at least one horizontal portion includes a horizontal rail formed in the horizontal direction, wherein the at least one vertical portion includes a roller which is movable along the horizontal rail. 
     The at least one horizontal portion includes first and second horizontal portions, which are positioned on the main frame in the horizontal direction and are parallel to each other, the first horizontal portion being positioned above the second horizontal portion in the vertical direction, wherein the roller includes a first roller corresponding to the horizontal rail formed in the first horizontal portion and a second roller corresponding to the horizontal rail formed in the second horizontal portion. 
     An axis of the first roller extends in a direction vertical to the horizontal direction and the vertical direction, wherein an axis of the second roller extends in the vertical direction. 
     The at least one vertical portion includes first and second vertical portions, which are hung on the first and second horizontal portions in the vertical direction and are positioned parallel to each other. 
     The at least one vertical portion includes: a base having a hole; a spring part fixed to the base; and a supporter connected to the spring part using a connection rod, a protrusion of the display module passing through the hole of the base and being hung on the supporter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings: 
         FIGS. 1 to 13  illustrate a configuration and a manufacturing method of a multi-display device according to an example embodiment of the invention; 
         FIGS. 14 to 30  illustrate a method for disposing a substrate in the front of a display module; 
         FIGS. 31 to 42  illustrate in detail a spacer; and 
         FIGS. 43 to 63  illustrate a method for supporting a plurality of display modules. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Reference will now be made in detail embodiments of the invention examples of which are illustrated in the accompanying drawings. Since the present invention may be modified in various ways and may have various forms, specific embodiments are illustrated in the drawings and are described in detail in the present specification. However, it should be understood that the present invention are not limited to specific disclosed embodiments, but include all modifications, equivalents and substitutes included within the spirit and technical scope of the present invention. 
     The terms ‘first’, ‘second’, etc. may be used to describe various components, but the components are not limited by such terms. The terms are used only for the purpose of distinguishing one component from other components. For example, a first component may be designated as a second component without departing from the scope of the present invention. In the same manner, the second component may be designated as the first component. 
     The term “and/or” encompasses both combinations of the plurality of related items disclosed and any item from among the plurality of related items disclosed. 
     When an arbitrary component is described as “being connected to “or” being linked to” another component, this should be understood to mean that still another component(s) may exist between them, although the arbitrary component may be directly connected to, or linked to, the second component. In contrast, when an arbitrary component is described as “being directly connected to” or “being directly linked to” another component, this should be understood to mean that no component exists between them. 
     The terms used in the present application are used to describe only specific embodiments or examples, and are not intended to limit the present invention. A singular expression can include a plural expression as long as it does not have an apparently different meaning in context. 
     In the present application, the terms “include” and “have” should be understood to be intended to designate that illustrated features, numbers, steps, operations, components, parts or combinations thereof exist and not to preclude the existence of one or more different features, numbers, steps, operations, components, parts or combinations thereof, or the possibility of the addition thereof. 
     Unless otherwise specified, all of the terms which are used herein, including the technical or scientific terms, have the same meanings as those that are generally understood by a person having ordinary knowledge in the art to which the present invention pertains. The terms defined in a generally used dictionary must be understood to have meanings identical to those used in the context of a related art, and are not to be construed to have ideal or excessively formal meanings unless they are obviously specified in the present application. 
     The following exemplary embodiments of the present invention are provided to those skilled in the art in order to describe the present invention more completely. Accordingly, shapes and sizes of elements shown in the drawings may be exaggerated for clarity. 
     Hereinafter, a plasma display panel (PDP) is used as an example of a display panel. Other display panels may be used. For example, a liquid crystal display (LCD) panel, a field emission display (FED) panel, and an organic light emitting diode (OLED) display panel may be used. 
       FIGS. 1 to 13  illustrate a configuration and a manufacturing method of a multi-display device according to an example embodiment of the invention. 
     As shown in  FIG. 1 , a multi-plasma display device  10  according to an example embodiment of the invention may include a plurality of plasma display panels  100 ,  110 ,  120 , and  130  which are positioned adjacent to one another. 
     A 1-1 driver  101  and a 1-2 driver  102  may supply driving signals to the first plasma display panel  100  of the plurality of plasma display panels  100 ,  110 ,  120 , and  130 . The 1-1 driver  101  and the 1-2 driver  102  may be integrated into one integrated driver. 
     Further, a 2-1 driver  111  and a 2-2 driver  112  may supply driving signals to the second plasma display panel  110 . 
     In other words, the multi-plasma display device  10  may be configured so that the plasma display panels  100 ,  110 ,  120 , and  130  included in the multi-plasma display device  10  receive the driving signals from different drivers, respectively. 
     A boundary area, i.e., a seam SA may be formed between the two adjacent plasma display panels. 
     Because the multi-plasma display device  10  implements an image by disposing the individual plasma display panels  100 ,  110 ,  120 , and  130  to be adjacent to one another, the seam SA may be formed between the two adjacent plasma display panels. 
     Each of the drivers shown in  FIG. 1  may be a driving board. 
     As shown in  FIG. 2 , a first plate  300  may be positioned on a back surface (i.e., a back surface of a back substrate of the first plasma display panel  100 ) of the first plasma display panel  100 . A second plate  310  may be positioned on a back surface of the second plasma display panel  110 , a third plate  320  may be positioned on a back surface of the third plasma display panel  120 , and a fourth plate  330  may be positioned on a back surface of the fourth plasma display panel  130 . The first to fourth plates  300  to  330  may be formed of a metal material. The first to fourth plates  300  to  330  may indicate a frame, a heat dissipation plate, a heat dissipation frame, a chassis, etc. 
     Driving boards for supplying the driving signals to the first to fourth plasma display panels  100  to  130  may be positioned on back surfaces of the first to fourth plates  300  to  330 . For example, as shown in  FIG. 3 , a 1-1 driver  101 , a 1-2 driver  102 , and a first controller  301  may be positioned on the back surface of the first plate  300  in a board form. A 2-1 driver  111 , a 2-2 driver  112 , and a second controller  311  may be positioned on the back surface of the second plate  310  in a board form. A 3-1 driver  121 , a 3-2 driver  122 , and a third controller  321  may be positioned on the back surface of the third plate  320  in a board form. A 4-1 driver  131 , a 4-2 driver  132 , and a fourth controller  331  may be positioned on the back surface of the fourth plate  330  in a board form. 
     The 1-1, 2-1, 3-1, and 4-1 drivers  101 ,  111 ,  121 , and  131  may supply driving signals to address electrodes of the first to fourth plasma display panels  100  to  130 . The 1-2, 2-2, 3-2, and 4-2 drivers  102 ,  112 ,  122 , and  132  may supply driving signals to scan electrodes and sustain electrodes of the first to fourth plasma display panels  100  to  130 . The first to fourth controllers  301 ,  311 ,  321 ,  331  may control the 1-1, 2-1, 3-1, and 4-1 drivers  101 ,  111 ,  121 , and  131  and the 1-2, 2-2, 3-2, and 4-2 drivers  102 ,  112 ,  122 , and  132 . 
     Hereinafter, the 1-1 driver  101 , the 1-2 driver  102 , and the first controller  301  may be referred to as a first driver  400 . The first driver  400  may supply the driving signals to the first plasma display panel  100 . 
     Hereinafter, the 2-1 driver  111 , the 2-2 driver  112 , and the second controller  311  may be referred to as a second driver  410 . The second driver  410  may supply the driving signals to the second plasma display panel  110 . 
     Hereinafter, the 3-1 driver  121 , the 3-2 driver  122 , and the third controller  321  may be referred to as a third driver  420 . The third driver  420  may supply the driving signals to the third plasma display panel  120 . 
     Hereinafter, the 4-1 driver  131 , the 4-2 driver  132 , and the fourth controller  331  may be referred to as a fourth driver  430 . The fourth driver  430  may supply the driving signals to the fourth plasma display panel  130 . 
       FIG. 3  shows that the first to fourth controllers  301  to  331  are respectively positioned on the back surfaces of the first to fourth plates  300  to  330 . However, the first to fourth controllers  301  to  331  may be integrated into one board. 
     The panel, the plate, and the driving board may configure a display module. In other words, the multi-plasma display device  10  includes a plurality of display modules  100 M,  110 M,  120 M, and  130 M which are positioned adjacent to one another. The plurality of display modules  100 M,  110 M,  120 M, and  130 M may include the plasma display panels, the plates, the driving boards, and a back cover (not shown). More specifically, the plurality of display modules  100 M,  110 M,  120 M, and  130 M may include the plasma display panels, the plates, the driving boards, the back cover, and at least one structure between the back cover and the plasma display panels. 
     As shown in  FIG. 4 , a plurality of display modules MDL may hang on a multi-supporter  20 . 
     As shown in  FIG. 4 , the multi-plasma display device  10  according to the embodiment of the invention may include the multi-supporter  20  and the plurality of display modules MDL hanging on the multi-supporter  20 . 
     The multi-supporter  20  may include a main frame  21  and a plurality of module supporters  22  connected to the main frame  21 . 
     The plurality of display modules MDL may respectively hang on the plurality of module supporters  22 . 
     As shown in  FIG. 5 , the multi-supporter  20  may be connected to a stand  30 . In this instance, the multi-plasma display device  10  may include the stand  30 , to which the multi-supporter  20  is connected, and thus may be called a stand type multi-plasma display device. 
     On the contrary, the stand  30  may be omitted in the multi-plasma display device  10 . For example, the multi-plasma display device  10  may be installed by hanging the multi-supporter  20  on a predetermined wall. In this instance, the multi-plasma display device  10  may be called a wall mounted type multi-plasma display device. 
     The plasma display panel may display an image in a frame including a plurality of subfields. 
     As shown in  FIG. 6 , each of the first to fourth plasma display panels  100  to  130  may include a front substrate  201 , on which a plurality of first electrodes  202  (or Y) and  203  (or Z) are formed, and a back substrate  211  on which a plurality of second electrodes  213  (or X) are formed to cross the first electrodes  202  and  203 . 
     In the embodiment of the invention, the first electrodes  202  and  203  may include scan electrodes  202  and sustain electrodes  203  parallel to each other, and the second electrodes  213  may be called address electrodes. 
     An upper dielectric layer  204  may be formed on the scan electrode  202  and the sustain electrode  203  to limit a discharge current of the scan electrode  202  and the sustain electrode  203  and to provide insulation between the scan electrode  202  and the sustain electrode  203 . 
     A protective layer  205  may be formed on the upper dielectric layer  204  to facilitate discharge conditions. The protective layer  205  may be formed of a material having a high secondary electron emission coefficient, for example, magnesium oxide (MgO). 
     A lower dielectric layer  215  may be formed on the address electrode  213  to provide insulation between the address electrodes  213 . 
     Barrier ribs  212  of a stripe type, a well type, a delta type, a honeycomb type, etc. may be formed on the lower dielectric layer  215  to provide discharge spaces (i.e., discharge cells). Hence, a first discharge cell emitting red light, a second discharge cell emitting blue light, and a third discharge cell emitting green light, etc. may be formed between the front substrate  201  and the back substrate  211 . The first, second, and third discharge cells may configure a pixel. 
     The address electrode  213  may cross the scan electrode  202  and the sustain electrode  203  in one discharge cell. Namely, each discharge cell is formed at a crossing of the scan electrode  202 , the sustain electrode  203 , and the address electrode  213 . 
     Each of the discharge cells provided by the barrier ribs  212  may be filled with a predetermined discharge gas. 
     A phosphor layer  214  may be formed inside the discharge cells to emit visible light for an image display during an address discharge. For example, first, second, and third phosphor layers that respectively generate red, blue, and green light may be formed inside the discharge cells. 
     While the address electrode  213  may have a substantially constant width or thickness, a width or thickness of the address electrode  213  inside the discharge cell may be different from a width or thickness of the address electrode  213  outside the discharge cell. For example, a width or thickness of the address electrode  213  inside the discharge cell may be greater than a width or thickness of the address electrode  213  outside the discharge cell. 
     When a predetermined signal is supplied to at least one of the scan electrode  202 , the sustain electrode  203 , and the address electrode  213 , a discharge may occur inside the discharge cell. The discharge may allow the discharge gas filled in the discharge cell to generate ultraviolet rays. The ultraviolet rays may be incident on phosphor particles of the phosphor layer  214 , and then the phosphor particles may emit visible light. Hence, an image may be displayed on the screen of the plasma display panel  100 . 
     A frame for achieving a gray scale of an image displayed in the plasma display module described with reference to  FIG. 7 . 
     As shown in  FIG. 7 , a frame for achieving a gray scale of an image may include a plurality of subfields. 
     Each of the plurality of subfields may be divided into an address period and a sustain period. During the address period, the discharge cells not to generate a discharge may be selected or the discharge cells to generate a discharge may be selected. During the sustain period, a gray scale may be achieved depending on the number of discharges. 
     For example, if an image with 256-gray level is to be displayed, as shown in  FIG. 7 , a frame may be divided into 8 subfields SF 1  to SF 8 . Each of the 8 subfields SF 1  to SF 8  may include an address period and a sustain period. 
     Furthermore, at least one of a plurality of subfields of a frame may further include a reset period for initialization. 
     At least one of a plurality of subfields of a frame may not include a sustain period. 
     The number of sustain signals supplied during the sustain period may determine a gray level of each of the subfields. For example, in such a method of setting a gray level of a first subfield at  2   0  and a gray level of a second subfield at  2   1 , the sustain period increases in a ratio of 2 n  (where, n=0, 1, 2, 3, 4, 5, 6, 7) in each of the subfields. Hence, various gray levels of an image may be achieved by controlling the number of sustain signals supplied during the sustain period of each subfield depending on a gray level of each subfield. 
     Although  FIG. 7  shows that one frame includes 8 subfields, the number of subfields constituting a frame may vary. For example, a frame may include 10 or 12 subfields. 
     Further, although  FIG. 7  shows that the subfields of the frame are arranged in increasing order of gray level weight, the subfields may be arranged in decreasing order of gray level weight or may be arranged regardless of gray level weight. 
     A driving waveform for driving the plasma display module is illustrated in  FIG. 8 . 
     As shown in  FIG. 8 , a reset signal RS may be supplied to the scan electrode Y during a reset period RP for initialization of at least one of a plurality of subfields of a frame. The reset signal RS may include a ramp-up signal RU with a gradually rising voltage and a ramp-down signal RD with a gradually falling voltage. 
     More specifically, the ramp-up signal RU may be supplied to the scan electrode Y during a setup period of the reset period RP, and the ramp-down signal RD may be supplied to the scan electrode Y during a set-down period following the setup period SU. 
     The ramp-up signal RU may generate a weak dark discharge (i.e., a setup discharge) inside the discharge cells. Hence, the wall charges may be uniformly distributed inside the discharge cells. 
     The ramp-down signal RD subsequent to the ramp-up signal RU may generate a weak erase discharge (i.e., a set-down discharge) inside the discharge cells. Hence, the remaining wall charges may be uniformly distributed inside the discharge cells to the extent that an address discharge occurs stably. 
     During an address period AP following the reset period RP, a scan reference signal Ybias having a voltage greater than a minimum voltage of the ramp-down signal RD may be supplied to the scan electrode Y. 
     In addition, a scan signal Sc falling from a voltage of the scan reference signal Ybias may be supplied to the scan electrode Y. 
     A pulse width of a scan signal supplied to the scan electrode during an address period of at least one subfield of a frame may be different from pulse widths of scan signals supplied during address periods of the other subfields of the frame. A pulse width of a scan signal in a subfield may be greater than a pulse width of a scan signal in a next subfield. For example, a pulse width of the scan signal may be gradually reduced in the order of 2.6 μs, 2.3 μs, 2.1 μs, 1.9 μs, etc. or may be reduced in the order of 2.6 μs, 2.3 μs, 2.3 μs, 2.1 μs, . . . , 1.9 μs, 1.9 μs, etc. in the successively arranged subfields. 
     As above, when the scan signal Sc is supplied to the scan electrode Y, a data signal Dt corresponding to the scan signal Sc may be supplied to the address electrode X. 
     As a voltage difference between the scan signal Sc and the data signal Dt is added to a wall voltage obtained by the wall charges produced during the reset period RP, an address discharge may occur inside the discharge cell to which the data signal Dt is supplied. 
     In addition, during the address period AP, a sustain reference signal Zbias may be supplied to the sustain electrode Z, so that the address discharge efficiently occurs between the scan electrode Y and the address electrode X. 
     During a sustain period SP following the address period AP, a sustain signal SUS may be supplied to at least one of the scan electrode Y or the sustain electrode Z. For example, the sustain signal SUS may be alternately supplied to the scan electrode Y and the sustain electrode Z. 
     Further, the address electrode X may be electrically floated during the sustain period SP. As the wall voltage inside the discharge cell selected by performing the address discharge is added to a sustain voltage Vs of the sustain signal SUS, every time the sustain signal SUS is supplied, a sustain discharge, i.e., a display discharge may occur between the scan electrode Y and the sustain electrode Z. 
     A method for manufacturing the multi-plasma display device according to the embodiment of the invention is schematically described below. 
     As shown in (a) of  FIG. 9 , a seal portion  500  may be formed at an edge of at least one of the front substrate  201  and the back substrate  211 , on which an exhaust hole  240  is formed. As shown in (b) of  FIG. 9 , the front substrate  201  and the back substrate  211  may be attached to each other through the seal portion  500 . 
     Subsequently, as shown in (c) of  FIG. 9 , an exhaust tip  250  may be connected to the exhaust hole  240 , and an exhaust pump  230  may be connected to the exhaust tip  250 . 
     The exhaust pump  230  may exhaust an impurity gas remaining in a discharge space between the front substrate  201  and the back substrate  211  to the outside and may inject a discharge gas such as argon (Ar), neon (Ne), and xenon (Xe) into the discharge space. 
     The discharge space between the front substrate  201  and the back substrate  211  may be sealed through the above-described method. 
     Next, as shown in (a) of  FIG. 10 , after the front substrate  201  and the back substrate  211  are attached to each other by sealing the discharge space between the front substrate  201  and the back substrate  211 , the front substrate  201  and the back substrate  211  may be partially cut along a predetermined cutting line CL. The grinding may be carried out along with the cutting. For example, one long side and one short side of each of the front substrate  201  and the back substrate  211  may be cut and ground. 
     As shown in (b) and (c) of  FIG. 10 , cutting portions of the substrates  201  and  211  may prevent at least one of the front substrate  201  and the back substrate  211  from excessively protruding. Hence, the size of the plasma display panel, on which the image is not displayed, may be reduced. 
     Further, as shown in (b) and (c) of  FIG. 10 , the seal portion  500  may be cut in a process for partially cutting the front substrate  201  and the back substrate  211 . As above, when the seal portion  500  is cut, the size of the plasma display panel, on which the image is not displayed, may be further reduced. 
     The display modules each including the plasma display panel manufactured using the method illustrated in  FIG. 10  may be disposed adjacent to one another to manufacture the multi-plasma display panel. 
     For example, as shown in  FIG. 11 , the first to fourth display modules  100 M,  110 M,  120 M, and  130 M may be arranged in a 2×2 matrix. 
     Further, the first to fourth display modules  100 M,  110 M,  120 M, and  130 M may be disposed, so that their cutting surfaces are adjacent to one another. 
     For example, the cutting and grinding processes may be performed on a second short side SS 2  and a second long side LS 2  of each of the first to fourth display modules  100 M,  110 M,  120 M, and  130 M. 
     More specifically, the second short side SS 2  of the first display module  100 M and the second short side SS 2  of the second display module  110 M may be positioned adjacent to each other. The second short side SS 2  of the third display module  120 M and the second short side SS 2  of the fourth display module  130 M may be positioned adjacent to each other. 
     Further, the second long side LS 2  of the first display module  100 M and the second long side LS 2  of the third display module  120 M may be positioned adjacent to each other. The second long side LS 2  of the second display module  110 M and the second long side LS 2  of the fourth display module  130 M may be positioned adjacent to each other. 
     As described above, when the first to fourth display modules  100 M,  110 M,  120 M, and  130 M are disposed so that their cutting surfaces are adjacent to one another, the size of the seam SA of the multi-plasma display device  10  may be reduced. Hence, the more natural image may be implemented. 
       FIG. 11  shows that the first to fourth display modules  100 M,  110 M,  120 M, and  130 M are arranged in a 2×2 matrix. Other matrix structures may be used. For example, the first to fourth display modules  100 M,  110 M,  120 M, and  130 M may be arranged in a 1×2 matrix or a 2×1 matrix. 
     Alternatively, as shown in  FIG. 12 , the first to fourth display modules  100 M,  110 M,  120 M, and  130 M are arranged in a 4×4 matrix. The structure of the 4×4 matrix may be applied to (3 or more rows)×(3 or more columns) matrixes. 
     Among first to sixteenth display modules  1000 M to  1330 M of the 4×4 matrix shown in  FIG. 12 , the first, second, fifth, and sixth display modules  1000 M,  1010 M,  1100 M, and  1110 M are described below as an example with reference to  FIG. 13 . 
     As shown in  FIG. 13 , the first and second display modules  1000 M and  1010 M may be positioned adjacent to each other in a first direction (or a horizontal direction) DRH, and the first and fifth display modules  1000 M and  1100 M may be positioned adjacent to each other in a second direction (or a vertical direction) DRV crossing the first direction DRH. Further, the sixth and second display modules  1110 M and  1010 M may be positioned adjacent to each other in the second direction. DRV, and the sixth and fifth display modules  1110 M and  1100 M may be positioned adjacent to each other in the first direction DRH. 
     The cutting and grinding processes may be performed on first and second short sides SS 1  and SS 2  and first and second long sides LS 1  and LS 2  of each of the first, second, fifth, and sixth display modules  1000 M,  1010 M,  1100 M, and  1110 M. 
     The second short side SS 2  of the first display module  1000 M and the first short side SS 1  of the second display module  1010 M may be positioned adjacent to each other. The second short side SS 2  of the fifth display module  1100 M and the first short side SS 1  of the sixth display module  1110 M may be positioned adjacent to each other. 
     The first long sides LS 1  of the first, second, and fifth display modules  1000 M,  1010 M, and  1100 M may be positioned adjacent to each other, and the second long side LS 2  of the second display module  1010 M and the first long side LS 1  of the sixth display module  1110 M may be positioned adjacent to each other. 
       FIGS. 14 to 30  illustrate a method for disposing a substrate in the front of a display module. In the following description, the descriptions of the configuration and the structure described above are omitted. 
     As shown in  FIG. 14 , each of a plurality of display modules MDL included in the multi-plasma display device according to the embodiment of the invention may include a display panel PNL for displaying an image, plates  300 ,  310 ,  320 , and  330  positioned in the rear of the display panel PNL, and a back cover  600  positioned in the rear of the plates  300  to  330 . The display panel PNL may be a plasma display panel. 
     Hereinafter, each of the plates  300  to  330  is referred to as a frame. 
     Each display module MDL may include at least one structure  630  between the frames  300  to  330  and the back cover  600 . The structure  630  may include a first auxiliary frame  610  and a second auxiliary frame  620 . 
     As shown in  FIGS. 15 and 16 , an adhesive layer AHDL may be positioned between the frames  300  to  330  and the display panel PNL. Namely, the frames  300  to  330  may be attached to a back substrate of the display panel PNL using the adhesive layer AHDL. 
     The first auxiliary frame  610  may be connected to the frames  300  to  330 . For example, as shown in  FIG. 16 , a supporter PM such as a pem nut may be positioned on the frames  300  to  330 , and the first auxiliary frame  610  may be fastened to the supporter PM using a fastener S 110  such as a screw.  FIG. 16  shows that the screw is used as the fastener. Other fasteners may be used. For example, a pin, a clip, etc. may be used. 
     The fastener S 110  may fasten both the first auxiliary frame  610  and the second auxiliary frame  620  to the frames  300  to  330 . 
     Alternatively, although not shown, the supporter PM may be omitted, and the first auxiliary frame  610  may be fastened to the frames  300  to  330  using a predetermined fastener. 
     Further, the second auxiliary frame  620  may be connected to the back cover  600 . For example, as shown in  FIG. 16 , the second auxiliary frame  620  may be fastened to the back cover  600  using the fastener S 110 . 
     Alternatively, although not shown, the first auxiliary frame  610  and the second auxiliary frame  620  may form an integral body. 
     Alternatively, the first auxiliary frame  610  and the second auxiliary frame  620  may be omitted. In this instance, as shown in  FIG. 17 , the frames  300  to  330  may be connected to the back cover  600 . For example, the supporter PM may be positioned on the frames  300  to  330 , and the back cover  600  may be fastened to the supporter PM using a fastener S 120 . 
     As shown in  FIG. 18 , substrates  220  to  223  may be respectively positioned in the front of the display modules  100 M,  110 M,  120 M, and  130 M. The substrates  220  to  223  may be a glass substrate or a plastic substrate. It may be preferable that the substrates  220  to  223  are the glass substrate so as to prevent the deformation by heat and/or external force. 
     In other words, the substrates  220  to  223  may be respectively positioned in the front of the front substrates of the display panels  100  to  130 . 
     As shown in  FIG. 19 , a side cover SC may be used to fix the substrates  220  to  223 . 
     As shown in  FIG. 19 , the side cover SC may be not positioned between the adjacent display modules  100 M to  130 M and may be positioned at an edge of the multi-plasma display device. 
     The side cover SC may be positioned on the sides of the display modules  100 M to  130 M and the sides of the substrates  220  to  223  and may be connected to the display modules  100 M to  130 M. The side cover SC may include a portion into which the substrates  220  to  223  are inserted. 
     For example, as shown in  FIG. 20 , the substrates  220  to  223  may be positioned in the front of the display panel PNL, and the side cover SC may include a portion R 100  into which ends of the substrates  220  to  223  are inserted. The portion R 100  of the side cover SC may be referred to as a rail. 
     The side cover SC may include a portion positioned on the side of the display panel PNL and a hole H 110  used in the connection between the display module MDL and the side cover SC. 
     The display module MDL may include a hole H 100  used in the connection between the display module MDL and the side cover SC. For example, as shown in  FIG. 20 , the hole H 100  of the display module MDL may be formed in the structure  630 , which is positioned between the frames  300  to  330  and the back cover  600  and connects the frames  300  to  330  to the back cover  600 .  FIG. 20  shows that the hole H 100  is formed in the second auxiliary frame  620  of the structure  630 . However, a position of the hole H 100  may be changed. For example, the hole H 100  may be formed in the first auxiliary frame  610  of the structure  630 . 
     The hole H 110  of the side cover SC may correspond to the hole H 100  of the structure  630 . Hence, a fastener S 130  may pass through the hole H 110  of the side cover SC and the hole H 100  of the structure  630  and may connect the side cover SC to the display module MDL. 
     In this instance, an air gap  2000  may be formed between the substrates  220  to  223  and the display panel PNL. 
     Alternatively, a hole used to fasten the display module MDL to the side cover SC may be formed in the back cover  600  of the display module MDL. 
     For example, as shown in  FIG. 21 , a hole H 120  used to connect the display module MDL to the side cover SC may be formed in the back cover  600 . The fastener S 130  pass through the hole H 120  of the back cover  600  and the hole H 110  of the side cover SC and may fasten the side cover SC to the display module MDL. 
     In this instance, the back cover  600  may be connected to the frames  300  to  330 . 
     The embodiment of the invention is described below, on the assumption that the structure  630  is positioned between the back cover  600  and the frames  300  to  330  and the structure  630  has the hole H 100 , for the sake of brevity and ease of reading. However, the embodiment of the invention is not limited thereto. 
     The side cover SC may include an outer cover and an inner cover. 
     For example, as shown in  FIG. 22 , the side cover SC may include an outer cover OSC and an inner cover ISC between the outer cover OSC and the substrates  220  to  223 . The inner cover ISC is detachable from the outer cover OSC. 
     Elasticity of the inner cover ISC may be greater than elasticity of the outer cover OSC. For this, the inner cover ISC may contain a flexible material, for example, a silicon material and a resin material. In this instance, the inner cover ISC may effectively protect an end of the display panel PNL for the damage. The outer cover OSC may contain a metal material, for example, aluminum. 
     A length S 10  of the outer cover OSC may be greater than a length S 11  of the inner cover ISC. More specifically, the length S 10  of the outer cover OSC in a third direction DRZ crossing the first and second directions DRH and DRV may be greater than the length S 11  of the inner cover ISC in the third direction DRZ. Further, the outer cover OSC may include a portion positioned on the sides of the substrates  220  to  223  and a portion positioned on the side of the display module MDL. 
     The outer cover OSC may include a hole H 110 , which is used to connect the display module MDL to the side cover SC, and a rail R 100  corresponding to the substrates  220  to  223 . The rail R 100  of the outer cover OSC may be referred to as a first rail. 
     The inner cover ISC may include a second rail R 110  positioned on the first rail R 100  of the outer cover OSC. The ends of the substrates  220  to  223  may be inserted into the second rail R 110  of the inner cover ISC. 
     As shown in  FIG. 23 , a cross section of the inner cover ISC may include a first portion  700  which is positioned on front surfaces FS of the substrates  220  to  223  and extends in the second direction DRV, a second portion  710  which extends from the first portion  700  in the third direction DRZ and is positioned on the sides of the substrates  220  to  223 , a third portion  720  which extends from the second portion  710  in the second direction DRV and is positioned on back surfaces RS of the substrates  220  to  223 , and a fourth portion  730  extending from the third portion  720  in the third direction DRZ. 
     The inner cover ISC may include a protrusion P 100  so as to reduce a contact area between the substrates  220  to  223  and the inner cover ISC. For example, the protrusion P 100  may protrude from the third portion  720  of the inner cover ISC to the substrates  220  to  223 . In this instance, the substrates  220  to  223  may easily move in the inner cover ISC, and an impact applied to the substrates  220  to  223  may be reduced. 
     The inner cover ISC may include a portion positioned on the side of the display panel PNL of the display module MDL. For example, the fourth portion  730  of the inner cover ISC may include a portion positioned on the side of the display panel PNL. 
       FIG. 23  shows that the protrusion P 100  is formed in the third portion  720  of the inner cover ISC. However, the protrusion P 100  may be formed in at least one of the first and second portions  700  and  710  of the inner cover ISC and may protrude to the substrates  220  to  223 . 
     The outer cover OSC may include at least one protrusion P 110  which extends to the display module MDL and is formed in an area not overlapping the inner cover ISC. The protrusion P 110  of the outer cover OSC may prevent a damage resulting from a collision between the side cover SC and the display module MDL. 
     So far, the embodiment of the invention described that the plurality of display modules respectively correspond to the substrates  220  to  223 . However, the plurality of display modules may correspond to one substrate. For example, as shown in  FIG. 24 , the multi-display device according to the embodiment of the invention may include a first common substrate CG 1  corresponding to the first and third display modules  100 M and  120 M and a second common substrate CG 2  corresponding to the second and fourth display modules  110 M and  130 M. 
     Comparing the structure of  FIG. 24  with the structure of  FIG. 19 , the first common substrate CG 1  may replace the first and third substrates  220  and  222  of  FIG. 19 , and the second common substrate CG 2  may replace the second and fourth substrates  221  and  223  of  FIG. 19 . 
     In the above structure, the number of substrates CG 1  and CG 2  may be less than the number of display modules  100 M to  130 M. 
     Even in this instance, the side cover SC may be positioned so as to dispose the first common substrate CG 1  in the front of the first and third display modules  100 M and  120 M. Further, the side cover SC may be positioned so as to dispose the second common substrate CG 2  in the front of the second and fourth display modules  110 M and  130 M. 
     In the structure illustrated in  FIG. 19 , as shown in (A) of  FIG. 25 , a first horizontal side cover SCH 1  of the side cover SC may be positioned on the first long side LS 1  of the first substrate  220 , and a first vertical side cover SCV 1  of the side cover SC may be positioned on the second short side SS 2  of the first substrate  220 . Further, a third vertical side cover SCV 3  of the side cover SC may be positioned on the second short side SS 2  of the third substrate  222 , and a third horizontal side cover SCH 3  of the side cover SC may be positioned on the second long side LS 2  of the third substrate  222 . In (A) of  FIG. 25 , ‘SCH 2 ’ denotes a second horizontal side cover, ‘SCH 4 ’ a fourth horizontal side cover, ‘SCV 2 ’ a second vertical side cover, and ‘SCV 4 ’ a fourth vertical side cover. 
     On the other hand, in the structure illustrated in  FIG. 24 , as shown in (B) of  FIG. 25 , a first horizontal side cover SCH 1  may be positioned on a first short side SS 1  of the first common substrate CG 1 , and a third horizontal side cover SCH 3 l may be positioned on a second short side SS 2  of the first common substrate CG 1 . A first vertical side cover SCV 1  and a third vertical side cover SCV 3  may be positioned on a second long side LS 2  of the first common substrate CG 1 . Further, a second horizontal side cover SCH 2  may be positioned on a first short side SS 1  of the second common substrate CG 2 , and a fourth horizontal side cover SCH 4  may be positioned on a second short side SS 2  of the second common substrate CG 2 . A second vertical side cover SCV 2  and a third vertical side cover SCV 3  may be positioned on a first long side LS 1  of the second common substrate CG 2 . 
     A first long side LS 1  of the first common substrate CG 1  and a second long side LS 2  of the second common substrate CG 2  may be positioned adjacent to each other. 
     At least one of a plurality of inner covers ISC may correspond to the plurality of substrates. In other words, as shown in  FIG. 26 , the plurality of substrates may be inserted into a second rail R 110  of at least one inner cover ISC. Namely, at least one inner cover ISC may commonly overlap the two adjacent display modules MDL. 
     For example, as shown in  FIGS. 26 and 27 , a third horizontal outer cover OSCH 3  and a fourth horizontal outer cover OSCH 4  may be positioned adjacent to each other. A second horizontal inner cover ISCH 2  may be positioned in first rails of the third and fourth horizontal outer covers OSCH 3  and OSCH 4 . 
     Ends of the first and second common substrates CG 1  and CG 2  may be inserted into a second rail of the second horizontal inner cover ISCH 2 . 
     In this instance, it is easy to align the first and second common substrates CG 1  and CG 2  in the multi-display device. 
     Considering that the inner cover ISC is formed so as to easily move the first and second common substrates CG 1  and CG 2  while preventing a damage of ends of the first and second common substrates CG 1  and CG 2 , a length L 1  of the inner cover ISC in the first direction DRH may be less than a length L 2  of the outer cover OSC in the first direction DRH as shown in  FIG. 27 . Alternatively, a length of the inner cover ISC in the second direction DRV may be less than a length of the outer cover OSC in the second direction DRV. 
     In this instance, as shown in (A) of  FIG. 28 , a first horizontal outer cover OSCH 1  may be positioned on the first short side SS 1  of the first common substrate CG 1 , and a third horizontal outer cover OSCH 3  may be positioned on the second short side SS 2  of the first common substrate CG 1 . Further, a second horizontal outer cover OSCH 2  may be positioned on the first short side SS 1  of the second common substrate CG 2 , and a fourth horizontal outer cover OSCH 4  may be positioned on the second short side SS 2  of the second common substrate CG 2 . 
     A first horizontal inner cover ISCH 1  may be positioned in rails of the first and second horizontal outer covers OSCH 1  and OSCH 2 . A second horizontal inner cover ISCH 2  may be positioned in rails of the third and fourth horizontal outer covers OSCH 3  and OSCH 4 . 
     The first long side LS 1  of the first common substrate CG 1  and the second long side LS 2  of the second common substrate CG 2  may be positioned adjacent to each other. 
     Alternatively, as shown in (B) of  FIG. 28 , a first horizontal side cover SCH 1  may be positioned on the first short side SS 1  of the first common substrate CG 1  and the first short side SS 1  of the second common substrate CG 2 . Further, a second horizontal side cover SCH 2  may be positioned on the second short side SS 2  of the first common substrate CG 1  and the second short side SS 2  of the second common substrate CG 2 . 
     The first horizontal side cover SCH 1  shown in (B) of  FIG. 28  may be obtained by integrating the first and second horizontal outer covers OSCH 1  and OSCH 2  shown in (A) of  FIG. 28  into one part and then disposing the first horizontal inner cover ISCH 1  in a rail of the integrated first and second horizontal outer covers OSCH 1  and OSCH 2 . 
     As shown in (B) of  FIG. 28 , the first vertical side cover SCV 1  may be positioned on the second long side LS 2  of the first common substrate CG 1 , and the second vertical side cover SCV 2  may be positioned on the first long side LS 1  of the second common substrate CG 2 . 
     As shown in  FIG. 29 , it is assumed that first to ninth display modules  1000 M to  1220 M are arranged in a 3×3 matrix. 
     In this instance, a first common substrate CG 10  may be disposed in the front of the first, fourth, and seventh display modules  1000 M,  1100 M, and  1200 M, and a second common substrate CG 20  may be disposed in the front of the second, fifth, and eighth display modules  1010 M,  1110 M, and  1210 M. A third common substrate CG 30  may be disposed in the front of the third, sixth, and ninth display modules  1020 M,  1120 M, and  1220 M. 
     In this instance, as shown in  FIG. 30 , a first horizontal outer cover OSCH 1  may be positioned on a first short side SS 1  of the first common substrate CG 10 , and a fourth horizontal outer cover OSCH 4  may be positioned on a second short side SS 2  of the first common substrate CG 10 . A second horizontal outer cover OSCH 2  may be positioned on a first short side SS 1  of the second common substrate CG 20 , and a fifth horizontal outer cover OSCH 5  may be positioned on a second short side SS 2  of the second common substrate CG 20 . A third horizontal outer cover OSCH 3  may be positioned on a first short side SS 1  of the third common substrate CG 30 , and a sixth horizontal outer cover OSCH 6  may be positioned on a second short side SS 2  of the third common substrate CG 30 . 
     A first horizontal inner cover ISCH 1  may be positioned in rails of the first and second horizontal outer covers OSCH 1  and OSCH 2 , and a second horizontal inner cover ISCH 2  may be positioned in rails of the second and third horizontal outer covers OSCH 2  and OSCH 3 . A third horizontal inner cover ISCH 3  may be positioned in rails of the fourth and fifth horizontal outer covers OSCH 4  and OSCH 5 , and a fourth horizontal inner cover ISCH 4  may be positioned in rails of the fifth and sixth horizontal outer covers OSCH 5  and OSCH 6 . 
     A first long side LS 1  of the first common substrate CG 10  and a second long side LS 2  of the second common substrate CG 20  may be adjacent to each other. A first long side LS 1  of the second common substrate CG 20  and a second long side LS 2  of the third common substrate CG 30  may be adjacent to each other. 
     First, second, and third vertical outer covers OSCV 1 , OSCV 2 , and OSCV 3  may be positioned on a second long side LS 2  of the first common substrate CG 10 . Further, fourth, fifth, and sixth vertical outer covers OSCV 4 , OSCV 5 , and OSCV 6  may be positioned on a first long side LS 1  of the third common substrate CG 30 . 
     A first vertical inner cover ISCV 1  may be positioned in rails of the first and second vertical outer covers OSCV 1  and OSCV 2 , and a second vertical inner cover ISCV 2  may be positioned in rails of the second and third vertical outer covers OSCV 2  and OSCV 3 . A third vertical inner cover ISCV 3  may be positioned in rails of the fourth and fifth vertical outer covers OSCV 4  and OSCV 5 , and a fourth vertical inner cover ISCV 4  may be positioned in rails of the fifth and sixth vertical outer covers OSCV 5  and OSCV 6 . 
     The first to sixth vertical outer covers OSCV 1  to OSCV 6  and the first to fourth vertical inner covers ISCV 1  to ISCV 4  may be omitted in the embodiment of the invention. 
       FIGS. 31 to 42  illustrate in detail a spacer. In the following description, the descriptions of the configuration and the structure described above are omitted. For example, the structure described below may be applied to the descriptions of  FIGS. 1 to 30 . 
     As shown in  FIG. 31 , a spacer GC may be positioned between the two adjacent display modules MDL to adjust a distance between the two adjacent display modules MDL. 
     As shown in  FIG. 32 , the spacer GC may include a base plate  800 , a first protrusion  810  positioned on a first surface S 1  of the base plate  800 , and a second protrusion  820  positioned on a second surface S 2  opposite the first surface S 1  of the base plate  800 . 
     In other words, the first protrusion  810  may protrude from the first surface S 1  of the base plate  800 , and the second protrusion  820  may protrude from the second surface S 2  of the base plate  800 . 
     An axis of the first protrusion  810  may be substantially the same as an axis of the second protrusion  820 . 
     One of the first protrusion  810  and the second protrusion  820  may have spirals. In the following description, the first protrusion  810  has the spirals as an example. 
     A surface roughness of a third surface S 3  adjacent to the first and second surfaces S 1  and S 2  of the base plate  800  as shown in (B) of  FIG. 33  may be greater than a surface roughness of the first and second surfaces S 1  and S 2  of the base plate  800  as shown in (A) of  FIG. 33 , so as to easily rotate the spacer GC. 
     In other words, the third surface S 3  of the base plate  800  of the spacer GC may have protuberances  801 . 
     The first and second protrusions  810  and  820  of the spacer GC may be inserted into holes of the display module MDL. 
     For example, as shown in  FIG. 34 , a structure  630 A of a first display module including a first display panel  100  may have a hole H 130 A corresponding to the spacer GC, and a structure  630 C of a third display module, which includes a third display panel  120  and is adjacent to the first display module, may have a hole H 130 C corresponding to the spacer GC. The hole H 130 A and H 130 C, which are formed in the structures  630 A and  630 C and correspond to the first and second protrusions  810  and  820  of the spacer GC, may be different from the hole H 100  shown in  FIG. 20 . 
     The disposition structure of the first and third display modules of  FIG. 34  may correspond to at least one of  FIGS. 11, 13, 18, 19, 24, 25, 28, 29, and 30 . 
       FIG. 34  shows that the holes H 130 A and H 130 C are formed in second auxiliary frames  620 A and  620 C of the structures  630 A and  630 C. However, a position of the holes H 130 A and H 130 C may be changed. For example, the holes H 130 A and H 130 C may be formed in first auxiliary frames  610 A and  610 C or back covers  600 A and  600 C. 
     The first protrusion  810  of the spacer GC may be inserted into the hole H 130 C of the third display module, and the second protrusion  820  of the spacer GC may be inserted into the hole H 130 A of the first display module. In this instance, the spacer GC may prevent the misalignment of the first and third display modules. 
     The hole H 130 C of the third display module, into which the first protrusion  810  having the spirals is inserted, may have spirals. 
     A user may adjust a distance between the first and third display modules as a method for rotating the base plate  800  of the spacer GC. 
     For example, as shown in  FIG. 35 , it is assumed that a distance between the first and third display panels  100  and  120  of the first and third display modules is set to ‘G 1 ’ in a state where the spacer GC is positioned between the first and third display modules. 
     In this instance, the user may rotate the base plate  800  of the spacer GC. Because the first protrusion  810  having the spirals is more deeply inserted into the hole H 130 C of the structure  630 C of the third display module, the distance between the first and third display panels  100  and  120  of the first and third display modules may be set to ‘G 2 ’ less than ‘G 1 ’. 
     The base plate  800  of the spacer GC may contact the first display module. When the first protrusion  810  of the spacer GC is most deeply inserted into the hole H 130 C of the structure  630 C of the third display module, the base plate  800  of the spacer GC may contact the first display module. 
     As shown in  FIG. 37 , the base plate  800  may include a portion, which protrudes further than the structures  630 A and  630 C to the backward by a predetermined length W 1  at a boundary of the adjacent first and third display modules, so as to more easily rotate the base plate  800 . Namely, the base plate  800  may include a portion protruding further than the structures  630 A and  630 C and/or the back covers  600 A and  600 C, so that the user can easily rotate the base plate  800  in the rear of the multi-display device. 
     Alternatively, as shown in  FIG. 38 , a diameter W 10  of the base plate  800  in a width direction (i.e., the third direction DRZ) of the display module MDL may be greater than a width W 13  of the structures  630 A and  630 C. More specifically, the diameter W 10  of the base plate  800  in the third direction DRZ may be greater than a width W 11  of the first auxiliary frames  610 A and  610 C of the structures  630 A and  630 C and/or a width W 12  of the second auxiliary frames  620 A and  620 C of the structures  630 A and  630 C. Further, the diameter W 10  of the base plate  800  may be greater than a sum W 13  (=W 11 +W 12 ) of the width W 11  of the first auxiliary frames  610 A and  610 C and the width W 12  of the second auxiliary frames  620 A and  620 C. In this instance, the base plate  800  may sufficiently protrude to the backward. 
     As shown in  FIG. 39 , a diameter W 20  of the first protrusion  810  having the spirals may be greater than a diameter W 21  of the second protrusion  820  not having the spiral. 
     Because the first protrusion  810  having the spirals is relatively strongly coupled with the hole H 130 C of the third display module, the first protrusion  810  may have the sufficient diameter. Thus, when the diameter W 20  of the first protrusion  810  having the spirals is greater than the diameter W 21  of the second protrusion  820  not having the spiral, the structural stability may be improved. 
     Further, because the first protrusion  810  having the spirals is relatively strongly coupled with the hole H 130 C of the third display module, a length L 10  of the first protrusion  810  does not need to be excessively long. 
     On the other hand, the second protrusion  820  not having the spiral may have a sufficient length L 20 , so as to strongly couple with the hole H 130 A of the first display module. 
     Hence, the length L 20  of the second protrusion  820  may be greater than the length L 10  of the first protrusion  810 . Alternatively, the length L 20  of the second protrusion  820  may be substantially equal to the length L 10  of the first protrusion  810 . 
     As shown in  FIG. 40 , the second protrusion  820  may include a portion which has a decreasing width as it goes from the bottom to the top. In other words, a width W 30  of a lower portion (adjacent to the base plate  800 ) of the second protrusion  820  may be greater than a width W 31  of an upper portion of the second protrusion  820 . 
     In this instance, the second protrusion  820  may be easily inserted into the hole H 130 A of the first display module. 
     Alternatively, as shown in  FIG. 41 , the second protrusion  820  may include a lower portion  821  adjacent to the base plate  800  and an upper portion  822  positioned on the lower portion  821 . The upper portion  822  may include a portion having a gradually decreasing width. The lower portion  821  may have the uniform width, 
     Even in this instance, the second protrusion  820  may be easily inserted into the hole H 130 A of the first display module. 
     A spacer GC may be positioned between the two adjacent display modules MDL in the first direction (i.e., the horizontal direction) DRH, and may be positioned between the two adjacent display modules MDL in the second direction (i.e., the vertical direction) DRV. 
     For example, as shown in  FIG. 42 , a plurality of first spacers GCH may be positioned parallel to one another between first and third display modules  100 M and  120 M and between second and fourth display modules  110 M and  130 M in the first direction DRH. Further, a plurality of second spacers GCV may be positioned parallel to one another between the first and second display modules  100 M and  110 M and between the third and fourth display modules  120 M and  130 M in the second direction DRV. 
       FIGS. 43 to 63  illustrate a method for supporting the plurality of display modules. In the following description, the descriptions of the configuration and the structure described above are omitted. For example, the structure described below may be applied to the descriptions of  FIGS. 1 to 42 . 
     As shown in  FIGS. 43 and 44 , a multi-supporter  20 , on which the plurality of display modules MDL are hang, may include a main frame  21  and a plurality of module supporters  22  connected to the main frame  21 . The display module MDL may be hung on each module supporter  22 . 
     As shown in  FIG. 44 , the main frame  21  may include a plurality of sub-main frames  21 A to  21 J. Namely, the plurality of sub-main frames  21 A to  21 J may configure one main frame  21 . 
     The plurality of sub-main frames  21 A to  21 J may be connected to one another. 
     For example, as shown in  FIG. 45 , the adjacent first and fourth sub-main frames  21 A and  21 D may be connected to each other using predetermined fasteners S 140  to S 143 . 
     More specifically, a first fastening structure  900 A may be positioned on the first sub-main frame  21 A, and a fourth fastening structure  900 D may be positioned on the fourth sub-main frame  21 D. 
     A hole for the fastening may be formed in the first fastening structure  900 A and/or the fourth fastening structure  900 D. A hole for the fastening may be formed in the first sub-main frame  21 A and/or the fourth sub-main frame  21 D. 
     The predetermined fasteners S 140  to S 143  may pass through the hole formed in the first fastening structure  900 A and/or the fourth fastening structure  900 D and the hole formed in the first sub-main frame  21 A and/or the fourth sub-main frame  21 D, thereby fastening the first sub-main frame  21 A to the fourth sub-main frame  21 D. 
     In the embodiment of the invention, the first fastening structure  900 A and the fourth fastening structure  900 D may be omitted. 
     As shown in  FIG. 46 , the module supporter  22  may include at least one horizontal portion  22 H connected to the first sub-main frame  21 A of the main frame  21  in a horizontal direction (i.e., the first direction DRH) and at least one vertical portion  22 V hanging in the second direction DRV vertical to the horizontal portion  22 H. 
     For example, a first horizontal portion  22 HA and a second horizontal portion  22 HB may be positioned on the first sub-main frame  21 A of the main frame  21 . The first horizontal portion  22 HA may be positioned above the second horizontal portion  22 HB. 
     A first vertical portion  22 VA and a second vertical portion  22 VB may be hung parallel to each other on the first horizontal portion  22 HA and the second horizontal portion  22 HB. The first and second vertical portions  22 VA and  22 VB may include a portion hanging on the first horizontal portion  22 HA and/or a portion hanging on the second horizontal portion  22 HB. 
     The multi-supporter  20  may further include a connector  22 C for connecting the first vertical portion  22 VA to the second vertical portion  22 VB. The connector  22 C may connect the plurality of vertical portions. 
     The embodiment of the invention describes that the two horizontal portions  22 H and the two vertical portions  22 V are positioned on one sub-main frame. The number of horizontal portions  22 H and/or the number of vertical portions  22 V positioned on one sub-main frame are not limited. 
     A horizontal rail may be formed on the horizontal portion  22 H. For example, as shown in (A) of  FIG. 47 , a first horizontal rail  22 HAR may be formed on the first horizontal portion  22 HA. As shown in (B) of  FIG. 47 , a second horizontal rail  22 HBR may be formed on the second horizontal portion  22 HB. 
     Alternatively, as shown in  FIG. 48 , both the first and second horizontal rails  22 HAR and  22 HBR may be formed on the first horizontal portion  22 HA. For example, the first horizontal rail  22 HAR may be formed on a first surface S 1  of the first horizontal portion  22 HA, and the second horizontal rail  22 HBR may be formed on a second surface S 2  adjacent to the first surface S 1  of the first horizontal portion  22 HA. A third surface S 3  of the first horizontal portion  22 HA is opposite to the first surface S 1 , and the second surface S 2  is opposite to the third surface S 3  and is adjacent to the first and fourth surfaces S 1  and S 4 . 
     The second horizontal portion  22 HB may substantially have the same structure as the first horizontal portion  22 HA. 
     The vertical portion  22 V of the module supporter  22  may have a plurality of holes. 
     For example, as shown in  FIG. 49 , each of the first vertical portion  22 VA and the second vertical portion  22 VB may have an upper hole  22 VH 1 T and a lower hole  22 VH 1 B. The upper hole  22 VH 1 T and the lower hole  22 VH 1 B may be used to hang the display module MDL on the module supporter  22 . 
     Each of the first and second vertical portions  22 VA and  22 VB may have a fastening hole H 140  for the connection between the connector  22 C and the first and second vertical portions  22 VA and  22 VB. The connector  22 C may have holes H 141  corresponding to the fastening holes H 140 . A predetermined fastener S 150  may pass through the holes H 141  of the connector  22 C and the fastening holes H 140 , thereby connecting the connector  22 C to the first and second vertical portions  22 VA and  22 VB 
     As shown in  FIG. 50 , the display module MDL may include a plurality of protrusions  1000  formed on the back cover  600 . Although not shown, the protrusions  1000  may be connected to the back cover  600  using a predetermined fastener. 
     As shown in  FIG. 51 , each of the protrusions  1000  may include a stand  1010 , a pillar  1020  positioned on the stand  1010 , and a head  1030  coupled with the pillar  1020 . 
     A width W 41  of the head  1030  may be less than a width W 40  of the stand  1010 . 
     The pillar  1020  may include a male screw, and the head  1030  may include a female screw corresponding to the male screw of the pillar  1020 . Hence, the pillar  1020  may be strongly coupled with the head  1030 . 
     The stand  1010  of the protrusion  1000  may be connected to the back cover  600  of the display module MDL. For example, although not shown, the stand  1010  may be connected to the back cover  600  using a predetermined fastener. Alternatively, although not shown, the fastener for fastening the stand  1010  to the back cover  600  may be formed on the stand  1010 . 
     The protrusions  1000  may be inserted into the upper hole  22 VH 1 T and/or the lower hole  22 VH 1 B of the vertical portion  22 V of the module supporter  22 , thereby hanging the display module MDL on the module supporter  22 . 
     As shown in  FIG. 52 , the upper hole  22 VH 1 T and/or the lower hole  22 VH 1 B of the vertical portion  22 V may include a portion having a diameter R 1  greater than the width W 41  of the head  1030  and a portion having a diameter R 2  less than the width W 41  of the head  1030 , so as to easily insert the protrusions  1000  into the upper hole  22 VH 1 T and/or the lower hole  22 VH 1 B of the vertical portion  22 V of the module supporter  22 . 
     The head  1030  of the protrusion  1000  may enter into the portion having the diameter R 1  of the upper hole  22 VH 1 T and/or the lower hole  22 VH 1 B of the vertical portion  22 V. Hence, as shown in  FIGS. 53 and 54 , the head  1030  of the protrusion  1000  may be positioned in the front of the upper hole  22 VH 1 T and/or the lower hole  22 VH 1 B of the vertical portion  22 V. The stand  1010  of the protrusion  1000  may be positioned on the opposite side of the head  1030 , i.e., in the rear of the upper hole  22 VH 1 T and/or the lower hole  22 VH 1 B of the vertical portion  22 V. Hence, the display module MDL may be hung on the vertical portion  22 V of the module supporter  22 . 
     As shown in  FIG. 55 , the vertical portion  22 V may include a base  22 VBE having a plurality of holes, a spring part GSP fixed to the base  22 VBE, and a supporter  22 VSP, on which the protrusion  1000  passing through the holes of the base  22 VBE is hung. 
     The vertical portion  22 V may further include a connection rod RD for connecting the spring part GSP to the supporter  22 VSP. 
     The vertical portion  22 V may further include fixers HCS 1  and HCS 2  for fixing the supporter  22 VSP to the base  22 VBE. The fixers HCS 1  and HCS 2  may be a fastener such as a screw. 
     The base  22 VBE of the vertical portion  22 V may have the upper hole  22 VH 1 T and the lower hole  22 VH 1 B corresponding to the protrusion  1000 . The upper hole  22 VH 1 T and the lower hole  22 VH 1 B were described in detail above. 
     The base  22 VBE of the vertical portion  22 V may have fixing holes  22 VH 2  and  22 VH 3  for fixing the supporter  22 VSP. 
     A spring fixer  22 VGS for disposing the spring part GSP may be formed on the base  22 VBE of the vertical portion  22 V. The spring fixer  22 VGS may have a hole  22 VH 4  into which a portion of the spring part GSP is inserted. 
     The supporter  22 VSP may have holes  22 VSPH 2  and  22 VSPH 3  used to fasten the supporter  22 VSP to the base  22 VBE. 
     The supporter  22 VSP may have a support hole  22 VSPH 1  corresponding to the upper hole  22 VH 1 T of the base  22 VBE. The upper hole  22 VH 1 T and the support hole  22 VSPH 1  may overlap each other. The size of the support hole  22 VSPH 1  may be greater than the size of the upper hole  22 VHIT. 
     The spring part GSP may be at least one of a gas spring and a hydraulic spring. 
     As shown in  FIG. 56 , when the spring part GSP is inserted into the hole  22 VH 4  of the spring fixer  22 VGS and the supporter  22 VSP is placed on the base  22 VBE, the upper hole  22 VH 1 T of the base  22 VBE may correspond to the support hole  22 VSPH 1 . 
     As shown in  FIG. 57 , when the protrusion  1000  is hung on the upper hole  22 VHIT and the support hole  22 VSPH 1 , the protrusion  1000  may pass through the upper hole  22 VH 1 T and may be hung on the support hole  22 VSPH 1 . 
     In this state, even if the user uses the small force because of the help of the spring part GSP, the user may easily lift the display module MDL. Hence, the user may easily install and dismantle the display module MDL. 
     In the multi-display device, the height of each of the display modules MDL may be easily adjusted. 
     After the height of each display module MDL is adjusted using the spring part GSP, the supporter  22 VSP may be fixed to the base  22 VBE of the vertical portion  22 V using the fixers HCS 1  and HCS 2 . For example, the fixers HCS 1  and HCS 2  may pass through the holes  22 VSPH 2  and  22 VSPH 3  of the supporter  22 VSP and the fixing holes  22 VH 2  and  22 VH 3  of the base  22 VBE, and thus the supporter  22 VSP may be fixed to the base  22 VBE of the vertical portion  22 V. 
     The vertical portion  22 V of the module supporter  22  may include at least one roller. 
     For example, as shown in  FIG. 58 , a first roller stand RSP 1  may be connected to the base  22 VBE of the vertical portion  22 V, and a first roller  1100  may be positioned on the first roller stand RSP 1 . More specifically, the base  22 VBE of the vertical portion  22 V may have at least one hole H 150  used to fasten the base  22 VBE to the first roller stand RSP 1 , and the first roller stand RSP 1  may have a hole H 151  used to fasten the base  22 VBE to the first roller stand RSP 1 . A predetermined fastener S 160  may be inserted into the hole H 150  of the base  22 VBE and the hole H 151  of the first roller stand RSP 1  to connect the first roller stand RSP 1  to the base  22 VBE. 
     An axis RAX of the first roller  1100  may extend in the third direction DRZ. Hence, the first roller  1100  may rotate on the axis RAX extending in the third direction DRZ. 
     Further, as shown in  FIG. 59 , the first roller stand RSP 1  may have a hole H 152  for connecting the first roller  1100  to the first roller stand RSP 1 . 
     The first roller  1100  may include a first shaft  1110 , a first caster  1120  inserted into the first shaft  1110 , a first bolt  1140 , a first nut  1150  coupled with the first bolt  1140 , and a first washer  1130  positioned between the first bolt  1140  and the first caster  1120 . 
     The first caster  1120  may rotate in a state the first caster  1120  is inserted into the first shaft  1110 . The first washer  1130  may prevent a reduction in a rotational force of the first caster  1120  resulting from the contact between the first bolt  1140  and the first caster  1120 . 
     The first bolt  1140  and the first nut  1150  may be replaced by other kinds of fasteners. For example, the first roller  1100  may be connected to the first roller stand RSP 1  using a rivet. 
     The vertical portion  22 V including the first roller  1100  may be hung on the horizontal portion  22 H. 
     For example, as shown in  FIG. 60 , the first roller  1100  of the vertical portion  22 V may be installed so that the first roller  1100  can move along the first horizontal rail  22 HAR of the first horizontal portion  22 HA. 
     The vertical portion  22 V of the module supporter  22  may include a second roller  1200  different from the first roller  1100 . 
     For example, as shown in  FIG. 61 , a second roller stand RSP 2  may be connected to the base  22 VBE of the vertical portion  22 V, and the second roller  1200  may be positioned on the second roller stand RSP 2 . More specifically, the base  22 VBE of the vertical portion  22 V may have at least one hole H 160  used to fasten the base  22 VBE to the second roller stand RSP 2 , and the second roller stand RSP 2  may have a hole H 161  used to fasten the base  22 VBE to the second roller stand RSP 2 . A predetermined fastener S 170  may be inserted into the hole H 160  of the base  22 VBE and the hole H 161  of the second roller stand RSP 2  to connect the second roller stand RSP 2  to the base  22 VBE. 
     An axis RBX of the second roller  1200  may extend in the second (or vertical) direction DRV. Hence, the second roller  1200  may rotate on the axis RBX extending in the second direction DRV. 
     Further, as shown in  FIG. 62 , the second roller stand RSP 2  may have a hole H 162  for connecting the second roller  1200  to the second roller stand RSP 2 . 
     The second roller  1200  may include a second shaft  1210 , a second caster  1220  inserted into the second shaft  1210 , a second bolt  1240 , a second nut  1250  coupled with the second bolt  1240 , and a second washer  1230  positioned between the second bolt  1240  and the second caster  1220 . 
     The second caster  1220  may rotate in a state the second caster  1220  is inserted into the second shaft  1210 . The second washer  1230  may prevent a reduction in a rotational force of the second caster  1220  resulting from the contact between the second bolt  1240  and the second caster  1220 . 
     The second bolt  1240  and the second nut  1250  may be replaced by other kinds of fasteners. 
     The vertical portion  22 V including the first and second rollers  1100  and  1200  may be hung on the first and second horizontal portions  22 HA and  22 HB. Hence, as shown in  FIG. 63 , the second roller  1200  of the vertical portion  22 V may be installed so that the second roller  1200  can move along the second horizontal rail  22 HBR of the second horizontal portion  22 HB. 
     Because the first roller  1100  is hung on the first horizontal portion  22 HA as shown in  FIG. 60 , the second roller  1200  may not hung on the second horizontal portion  22 HB. 
     As described above, when the first and second rollers  1100  and  1200  are used, the user may easily move each of the display modules MDL hung on the module supporter  22  in the horizontal direction. Further, the user may easily adjust the distance between the display modules MDL of the multi-display device in the horizontal direction. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.