Abstract:
This invention provides a plasma tube array-type display sub-module capable of reducing a possibility of occurrence of troubles on a plasma tube array during a manufacturing process even in a case where irregularities are formed on the back side of the plasma tube array, and a display device. The plasma tube array-type display sub-module comprises a plasma tube array including a plurality of plasma tubes arranged in parallel, the plasma tube array being held between an address electrode support sheet having address electrodes formed thereon and a display electrode support sheet having display electrodes formed thereon, wherein the plasma tube array is fixed to a sub-module frame through an intermediate layer that is made of a material more flexible than that of the plasma tube array and can deform along the irregularities on the address electrode support sheet of the plasma tube array.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and the benefit of Japanese Application Ser. No. 2008-161239 which was filed Jun. 20, 2008, entitled Plasma Tube Array-Type Display Sub-Module and Display Device, and Japanese Application Ser. No. 2009-102715 which was filed Apr. 21, 2009, entitled Plasma Tube Array-Type Display Sub-Module and Display Device, the entirety of each being hereby incorporated by reference as if fully set forth herein. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a plasma tube array-type display sub-module comprising a plasma tube array having a plurality of plasma tubes arranged in parallel, and a display device. More specifically, the present invention relates to a plasma tube array-type display sub-module which can be attached reliably to a sub-module frame without causing any troubles on a plasma tube array even in a case where an address electrode support sheet on the back side of the plasma tube array has irregularities, and a display device. 
     2. Description of the Related Art 
     As a technology for realizing a next-generation large-screen display device, a plasma tube array-type display sub-module has been developed with a structure that a plurality of plasma tubes each filled with a discharge gas is arranged in parallel. For example, a large-screen display device having a scale of several meters by several meters in size can be constructed of a plasma tube array-type display system module that a plurality of plasma tube array-type display sub-modules of one square-meter in size is joined to one another. The display device of such a type that the plurality of plasma tube array-type display sub-modules is joined to one another does not need either a large glass substrate to be handled, like an LCD, a PDP and the like, nor a large-scale facility and achieves even image quality at low cost. 
     Typically, a large-screen plasma tube array-type display device can be constructed as follows. That is, a plasma tube array-type display sub-module is prepared in such a manner that a plasma tube array is integrated with a structural body called a sub-module frame of a certain size. Then, the plurality of plasma tube array-type display sub-modules is joined to one another. Herein, the “plasma tube array-type display sub-module” refers to a display film component as described above which includes a plasma tube, that is, a semi-finished product of a display panel, which dos not have a drive circuit, a power supply circuit and the like incorporated.  FIGS. 1A to 1C  are perspective views each of which shows a schematic configuration of a plasma tube array of a conventional plasma tube array-type display sub-module. More specifically,  FIG. 1A  is a perspective view schematically showing the configuration of the plasma tube array of the plasma tube array-type display sub-module.  FIG. 1B  is a perspective view partly showing the configuration of the plasma tube array of the plasma tube array-type display sub-module.  FIG. 1C  is a perspective view showing a state that the plasma tube array-type display sub-modules are joined vertically and horizontally to one another. 
     As shown in  FIG. 1A , a conventional plasma tube array-type display sub-module  30  has a rectangular shape as it comprises a part of a rectangular screen and a plurality of plasma tubes  31 ,  31 , . . . each filled with a discharge gas is arranged in parallel. The plasma tube  31  is a discharging thin tube made of glass, which diameter is not particularly limited, but preferably about 0.5 to 5 mm. Herein, for example, the plasma tube array-type display sub-module  30  of one square-meter in size is constructed in such a manner that 1000 pieces of glass thin tubes each having a diameter of 1 mm, a length of 1 m and an oblate ellipsoid section are arranged in parallel by a set of several pieces. The section of the thin tube is not particularly limited in shape, and examples thereof may include a circular section, an oblate ellipsoid section, a square section and the like. Moreover, the plasma tube  31  is filled with a discharge gas such as neon, xenon and the like at a predetermined ratio at a predetermined pressure. 
     The plurality of plasma tubes  31 ,  31 , . . . arranged in parallel is held between a back-side address electrode support sheet  33 , which comprises a plurality of address electrodes  32 ,  32 , . . . formed thereon so as to be in contact with the lower side of the plasma tubes  31 ,  31 , . . . in the longitudinal direction of the plasma tubes  31 ,  31 , . . . , and a front-side display electrode support sheet  35 , which comprises a plurality of display electrodes  34 ,  34 , . . . formed thereon so as to cross the upper side of the plasma tubes  31 ,  31 , . . . in the direction orthogonal to the longitudinal direction of the plasma tubes  31 ,  31 , . . . . Herein, the display electrode support sheet  35  is a flexible sheet made of, for example, a polycarbonate film, a PET (polyethylene terephthalate) film or the like. 
     The plurality of display electrodes  34 ,  34 , . . . is formed in stripes on the inner surface of the display electrode support sheet  35  so as to be contact with the plasma tubes  31 ,  31 , . . . and to cross the upper side of the plasma tubes  31 ,  31 , . . . . The plurality of adjacent display electrodes  34 ,  34  forming a display electrode pair functions as an X electrode and a Y electrode. Display discharge occurs inside the plasma tubes  31 ,  31 , . . . located between the X electrode and the Y electrode. In addition to the stripe pattern, the pattern of the display electrodes  34 ,  34 , . . . may be a pattern which is publicly known in the relevant technical field, and examples thereof may include a mesh pattern, a ladder pattern, a comb pattern and the like. Moreover, examples of the material for the display electrode  34  may include transparent conductive materials such as ITO (Indium Tin Oxide) and SnO 2 , and metal conductive materials such as Ag, Au, Al, Cu and Cr and the like. 
     The display electrode  34  can be formed by various methods which are publicly known in the relevant technical field. For example, the display electrode  34  may be formed by using a thick film technology, such as a printing, or by using a thin film technology such as a physical deposition method or a chemical deposition method. Examples of the thick film technology may include a screen print method and the like. With regard to the thin film technology, examples of the physical deposition method may include an evaporation method, a sputtering method and the like whereas examples of the chemical deposition method may include a thermal CVD method, a photo CVD method, a plasma CVD method and the like. 
     The plurality of address electrodes  32 ,  32 , . . . is formed on the back side of the plasma tube array-type display sub-module  30  per plasma tube  31  along the longitudinal direction of the plasma tubes  31 ,  31 , . . . , wherein an emit light cell is formed at an intersection of the address electrode  32  and the paired display electrode  34 . The address electrode  32  can be formed by various materials and methods which are publicly known in the relevant technical field. 
     In the configuration described above, as shown in  FIG. 1B , the plasma tube array-type display sub-module  30  achieves color display in such a manner that each plasma tube  31  comprises a single-color phosphor layer  36 . Examples of the phosphor layers  36 ,  36 , . . . comprise a red (R) phosphor layer  36 R, a green (G) phosphor layer  36 G and a blue (B) phosphor layer  36 B. A set of the plasma tube  31  comprising the red (R) phosphor layer  36 R, the plasma tube  31  comprising the green (G) phosphor layer  36 G and the plasma tube  31  comprising the blue (B) phosphor layer  36 B forms one pixel, so that the plasma tube array-type display sub-module  30  can achieve color display. Herein, the red (R) phosphor layer  36 R is made of a phosphor material such as (Y,Gd)BO 3 :EU 3+  in order to emit red light by irradiation with ultraviolet rays. The green (G) phosphor layer  36 G is made of a phosphor material such as Zn 2 SiO 4 :Mn in order to emit green light by irradiation with ultraviolet rays. The blue (B) phosphor layer  36 B is made of a phosphor material such as BaMgAl 12 O 17 :Eu 2+  in order to emit blue light by irradiation with ultraviolet rays. In order to enhance flexibility of the plasma tube array-type display sub-module  30  and facilitate the assembly thereof, preferably, a plasma tube unit is prepared in such a manner that the plurality of the set of the three plasma tubes for three colors R, G, B is attached to the reed-shaped back-side address electrode support sheet  33  in parallel, and then the plurality of plasma tube units is attached to the front-side display electrode support sheet  35 , so that the plasma tube array-type display sub-module  30  for a color display is fabricated. 
     The perspective view in  FIG. 1C  schematically shows a plasma tube array-type display system module  45  that the plurality of plasma tube array-type display sub-modules  30 ,  30 , . . . is joined vertically and horizontally to one another. As shown in  FIG. 1C , herein, four pieces of plasma tube array-type display sub-modules  30 ,  30 , . . . construct one plasma tube array-type display system module  45  for a large screen. Each plasma tube array-type display sub-module  30  is a semi-finished product which does not have a drive circuit, a power supply circuit and the like incorporated. After construction of the large-screen plasma tube array-type display system module  45 , a drive circuit, a power supply circuit and the like are incorporated in the plasma tube array-type display system module  45  defining the whole system module as one display film. Thus, a large-screen display device can be constructed, which has a feature suppressing a variation in quality of images displayed on the respective plasma tube array-type display sub-modules  30 ,  30 , . . . . The plasma tube array-type display sub-modules  30 ,  30  joined horizontally to each other can be driven simultaneously by connecting the display electrodes  34 ,  34  in the connection structure according to the present invention. For the plasma tube array-type display sub-modules  30 ,  30  joined vertically to each other, the respective address electrodes  32 ,  32  are lead to the upper side and the lower side of the screen so as to be connected to an address drive circuit, whereby the screens of the upper two plasma tube array-type display sub-modules  30 ,  30  and the screens of the lower two plasma tube array-type display sub-modules  30 ,  30  can be simultaneously driven by a publicly known method, so-called dual scan technique without connecting the respective address electrodes  32 ,  32 . 
     As described above, the plasma tube array itself is configured such that the plurality of plasma tubes  31 ,  31 , . . . is held between the address electrode support sheet  33  which is a flexible sheet and the display electrode support sheet  35 . Therefore, it is difficult to keep the shape of the plasma tubes  31 ,  31 , . . . , under such a condition. Accordingly, in general, the plasma tube array is attached to the structural body called a sub-module frame to form the plasma tube array-type display sub-module  30 , and the plurality of plasma tube array-type display sub-modules  30 ,  30 , . . . is joined to one another to form a display panel for a large-screen display device. 
     However, the address electrode support sheet  33  on the back side of the plasma tube array might have deformation such as distortion, warpage and the like and the irregularities caused by a projection (burr) on a cutting surface generated upon cutting. Moreover, since a production error is generated on the plasma tube  31  itself, the size such as the diameter is non-constant. Therefore, when the plasma tube array is held between the address electrode support sheet  33  and the display electrode support sheet  35 , irregularities might also be generated on the display electrode support sheet  35 . 
     When the plasma tube array is attached to a flat sub-module frame, called a support plate, with such irregularities generated, the back side of the plasma tube array is forced to be flattened on the surface of the sub-module frame, which causes a stress and the like to arise problems of the deformation of the plasma tube array, generation of residual stress, separation of the address electrode support sheet  33  or the display electrode support sheet  35  from the plasma tube array, and the like. 
     Since the plurality of plasma tubes  31 ,  31 , . . . is arranged in parallel, the shape of each plasma tube  31  slightly varies due to the pressure variation or temperature change inside the plasma tube  31 , when a drive voltage is applied thereto. Moreover, the production precision itself varies for each plasma tube  31 , wherein the size, i.e., the diameter, of each the plasma tube  31  varies. These factors are correlated with each other, resulting in that, depending upon a drive input pattern, resonance occurs with a vibration mode specific to the plasma tube array, and therefore, an abnormal noise is generated from the surface of the plasma tube array. 
     In order to avoid the abnormal noise leaking from the front side of the display device, a noise insulation film with a noise insulating effect has to be provided on the front side of the display screen. For example, JP 2003-043937 A discloses a display filter (film) aiming to ease shock of a plasma display. This filter can ease the external shock, but JP 2003-043937 A does not disclose nor suggest the function to avoid the abnormal noise, which is generated from the inside, leaking to the outside. 
     SUMMARY OF THE INVENTION 
     The present invention has been devised in view of the circumstances described above, and an object thereof is to provide a plasma tube array-type display sub-module and a display device, which can reduce a possibility of causing any troubles on a plasma tube array during a manufacturing process even in a case where an address electrode support sheet on the back side of the plasma tube array has irregularities. 
     Another object of the present invention is to provide a display device which can effectively avoid an abnormal noise, which is generated from the surface of the plasma tube array, leaking from the front side of the display device. 
     In order to accomplish the objects described above, a first aspect of the present invention is directed to a plasma tube array-type display sub-module comprising an address electrode support sheet having a plurality of address electrodes formed thereon, a display electrode support sheet having a plurality of display electrodes formed thereon, and a plurality of plasma tubes each filled with a discharge gas, arranged in parallel and held between the address electrode support sheet and the display electrode support sheet, wherein the plasma tube array is fixed to a sub-module frame through an intermediate layer which can deform along the surface shape of the address electrode support sheet on the back side. 
     According to the first aspect of the present invention, the plasma tube array is fixed to the sub-module frame through the intermediate layer that can deform along the surface shape of the address electrode support sheet on the back side. Since the intermediate layer can deform along the surface shape of the address electrode support sheet on the back side so as to support the plasma tube array in any surface shape on the back side, residual stress is not caused on the plasma tube array, whereby it can be prevented that the irregularities are generated on the surface of the display electrode support sheet on the front side. 
     A second aspect of the present invention is directed to the plasma tube array-type display sub-module according to the first aspect of the present invention, wherein an adhesive layer that bonds the address electrode support sheet to the plasma tubes is a solvent type adhesive layer, and the adhesive layer bonds the address electrode support sheet to the plasma tubes at the position where the adhesive layer is not in contact with the intermediate layer. 
     According to the second aspect of the present invention, the adhesive layer that bonds the address electrode support sheet to the plasma tubes is a solvent type adhesive layer. Therefore, when the intermediate layer and the adhesive layer are brought into contact with each other, especially in the case that a solvent type acrylic resin is used for both the adhesive layer and the intermediate layer, a chemical reaction occurs, whereby both layers may be dissolved. In view of this, the address electrode support sheet and the plasma tubes are bonded at the position where the adhesive layer is not in contact with the intermediate layer. With this structure, there is no possibility of the contact between the adhesive layer, which bonds the address electrode support sheet and the plasma tubes, and the intermediate layer. Further, the thickness of the intermediate layer can be reduced. Therefore, the plasma tube array-type display sub-module constituting a thin display device can be provided of high quality. 
     A third aspect of the present invention is directed to the plasma tube array-type display sub-module according to the first aspect of the present invention, wherein the intermediate layer is formed so as to be in contact with a first adhesive layer, which bonds the address electrode support sheet that is divided by the plurality of plasma tubes and the plasma tubes, and a second adhesive layer, which bonds the display electrode support sheet and the plasma tubes, through a gap between the adjacent address electrode support sheets and a clearance between the adjacent plasma tubes. 
     According to the third aspect of the present invention, even when the intermediate layer is brought into contact with the first adhesive layer which bonds the address electrode support sheet that is divided by the plurality of plasma tubes and the plasma tubes and the second adhesive layer which bonds the display electrode support sheet and the plasma tubes, through the gap between the adjacent address electrode support sheets and the clearance between the adjacent plasma tubes, a chemical reaction does not occur between them, so that the plasma tube array can be fixed to the sub-module frame without deteriorating the quality of the plasma tube array. Since the intermediate layer can support each of the plasma tubes so as to fix it at a predetermined position, the generation of a specific abnormal noise, due to the vibration of the plasma tubes, can be prevented. 
     A fourth aspect of the present invention is directed to the plasma tube array-type display sub-module according to the first aspect of the present invention, wherein the intermediate layer is formed so as to be in contact with a first adhesive layer, which bonds the address electrode support sheet that is divided by the plurality of plasma tubes and the plasma tubes, through a gap between the address electrode support sheets and a clearance between the adjacent plasma tubes, and a second adhesive layer, which bonds the display electrode support sheet and the plasma tubes, bonds the display electrode support sheet and the plasma tubes at the position where the second adhesive layer is not in contact with the intermediate layer. 
     According to the fourth aspect of the present invention, the intermediate layer is formed so as to be in contact with the first adhesive layer, which bonds the address electrode support sheet that is divided by the plurality of plasma tubes and the plasma tubes through the gap between the adjacent address electrode support sheets and the clearance between the adjacent plasma tubes, and the second adhesive layer, which bonds the display electrode support sheet and the plasma tubes, bonds the display electrode support sheet and the plasma tubes at the position where the second adhesive layer is not in contact with the intermediate layer. Therefore, a different type of glue can be used for the first adhesive layer and the second adhesive layer. On the other hand, the type of the glue does not need to be limited, for example, a solvent type acrylic resin can be used for both the first adhesive layer and the second adhesive layer, since the second adhesive layer is not in contact with the intermediate layer. Accordingly, even if a glue with broad utility is used, the intermediate layer can support the plasma tube array as deformed along the surface shape of the address electrode support sheet on the back side. Therefore, cost can be reduced, and further, the generation of the irregularities on the surface shape of the display electrode support sheet on the front side can be prevented. 
     A fifth aspect of the present invention is directed to a display device comprising the plurality of plasma tube array-type display sub-modules according to any one of the first to fourth aspects of the present invention joined to one another. 
     According to the fifth aspect of the present invention, when the plurality of plasma tube array-type display sub-modules described above is joined vertically and horizontally to one another to constitute a display panel, the intermediate layer can support the plasma tube array as deformed along the surface shape of the address electrode support sheet on the back side, even if the plasma tube array has any surface shape on the back side. Accordingly, the residual stress is not caused on the plasma tube array, and the generation of the irregularities on the surface shape of the display electrode support sheet on the front side can be prevented. Consequently, the deterioration in an electrical characteristic due to the change in the internal structure can be prevented, whereby a display device that can provide a high-quality image can be provided. 
     A sixth aspect of the present invention is directed to a display device comprising a plurality of plasma tube each filled with a discharge gas, an address electrode support sheet on the back side having a plurality of address electrodes formed along a longitudinal direction of the plasma tubes, a display electrode support sheet on the front side having a plurality of display electrodes extending in the direction of crossing all the plasma tubes, and the plurality of plasma tubes arranged in parallel and held between the address electrode support sheet and the display electrode support sheet, wherein a hard back support plate is provided through an intermediate layer flexible enough to deform along the surface shape of the address electrode support sheet on the back side. 
     According to the sixth aspect of the present invention, the hard back support plate is provided through the intermediate layer flexible enough to deform along the surface shape of the address electrode support sheet on the back side. Therefore, the intermediate layer can support the plasma tube array in any surface shape on the back side by deforming along the surface shape of the address electrode support sheet on the back side. Accordingly, the residual stress is not caused on the plasma tube array, and irregularities of the surface shape of the display electrode support sheet on the front side can be prevented from being generated. Since the intermediate layer with flexibility is provided on the back side of the address electrode support sheet, the intermediate layer can absorb a specific abnormal noise generated from the surface of the plasma tube array, whereby the present invention can provide a display device that does not give uncomfortable feeling by the noise to a person seeing an image. 
     A seventh aspect of the present invention is directed to the display device according to the sixth aspect, wherein the intermediate layer is made of a gel-like material with a Young&#39;s modulus of not less than 10 KPa and not more than 200 KPa. 
     An eighth aspect of the present invention is directed to the display device according to the sixth or seventh aspect of the present invention, wherein the back support plate is made of a hard plastic with a Young&#39;s modulus of not less than 1000 KPa and not more than 4000 KPa. 
     According to the seventh aspect and the eighth aspect of the present invention, the intermediate layer is made of a gel-like material with a Young&#39;s modulus of not less than 10 KPa and not more than 200 KPa, and/or the back support plate is made of a hard plastic with a Young&#39;s modulus of not less than 1000 KPa and not more than 4000 KPa. Therefore, the intermediate layer can support the plasma tube array in any surface shape on the back side by deforming along the surface shape of the address electrode support sheet on the back side. Accordingly, the residual stress is not caused on the plasma tube array, and the irregularities on the surface shape of the display electrode support sheet on the front side can be prevented from being generated. Since the intermediate layer with flexibility is provided on the back side of the address electrode support sheet, the intermediate layer can absorb the specific abnormal noise generated from the surface of the plasma tube array, whereby the present invention can provide a display device that does not give uncomfortable feeling by the noise to a person seeing an image. 
     Furthermore, in order to achieve the objects described above, a ninth aspect of the present invention is directed to a display device comprising a plurality of plasma tube each filled with a discharge gas, an address electrode support sheet on the back side having a plurality of address electrodes formed along a longitudinal direction of the plasma tubes, a display electrode support sheet on the front side having a plurality of display electrodes extending in the direction of crossing all the plasma tubes thereon, and the plurality of plasma tubes arranged in parallel and held between the address electrode support sheet and the display electrode support sheet; wherein a hard back support plate with a noise reflecting function is provided through an intermediate layer with a noise absorbing function that can deform along the surface shape of the address electrode support sheet on the back side. 
     According to the ninth aspect of the present invention, the hard back support plate with a noise reflecting function is provided through the intermediate layer with a noise absorbing function which can deform along the surface shape of the address electrode support sheet on the back side. Therefore, the intermediate layer can support the plasma tube array in any surface shape by deforming along the surface shape of the address electrode support sheet on the back side. The intermediate layer can absorb a specific abnormal noise generated from the surface of the plasma tube array, whereby the present invention can provide a display device that does not give uncomfortable feeling by the noise to a person seeing an image. 
     A tenth aspect of the present invention is directed to the display device according to the ninth aspect of the present invention, wherein the intermediate layer is made of a gel-like material and the back support plate is made of a hard plastic. 
     According to the tenth aspect of the present invention, the intermediate layer is made of a gel-like material and the back support plate is made of a hard plastic. Therefore, the intermediate layer can support the plasma tube array in any surface shape on the back side by deforming along the surface shape of the address electrode support sheet on the back side. The intermediate layer can absorb the specific abnormal noise generated from the surface of the plasma tube array, whereby the present invention can provide a display device that does not give uncomfortable feeling by the noise to a person seeing an image. 
     As described above, the plasma tube array is fixed to the sub-module frame through the intermediate layer that can deform along the surface shape of the address electrode support sheet on the back side. Therefore, the intermediate layer can support the plasma tube array in any surface shape on the back side by deforming along the surface shape of the address electrode support sheet on the back side. Accordingly, the residual stress is not caused on the plasma tube array, and the irregularities on the surface of the display electrode support sheet on the front side can be prevented from being generated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A to 1C  are perspective views each of which shows a schematic configuration of a plasma tube array of a conventional plasma tube array-type display sub-module; 
         FIGS. 2A and 2B  are sectional views, orthogonal to plasma tubes of a plasma tube array; 
         FIGS. 3A and 3B  are illustrations each of which shows a configuration of a plasma tube array-type display sub-module using the plasma tube array with irregularities; 
         FIG. 4  is an illustration which shows the configuration of the plasma tube array-type display sub-module using the plasma tube array with the irregularities, when an address electrode support sheet is provided for every plasma tube; 
         FIG. 5  is an illustrative sectional view along the plasma tubes on the side including the address electrode support sheet, which shows the plasma tube array-type display sub-module using the plasma tube array with the irregularities; 
         FIGS. 6A and 6B  are sectional views, orthogonal to the plasma tubes, each of which shows the schematic configuration of the plasma tube array-type display sub-module according to a first embodiment of the present invention; 
         FIGS. 7A and 7B  are illustrative sectional views along the plasma tubes on the side including the address electrode each of which shows the plasma tube array-type display sub-module according to the first embodiment of the present invention; 
         FIGS. 8A and 8B  are sectional views, orthogonal to the plasma tubes, each of which shows the schematic configuration of the plasma tube array-type display sub-module according to the first embodiment of the present invention; 
         FIGS. 9A and 9B  are sectional views, orthogonal to the plasma tubes, each of which shows the schematic configuration of the plasma tube array-type display sub-module according to a second embodiment of the present invention; 
         FIGS. 10A and 10B  are sectional views, orthogonal to the plasma tubes, each of which shows the schematic configuration of the plasma tube array-type display sub-module according to the second embodiment of the present invention, when the address electrode support sheet is provided for every plasma tube; 
         FIGS. 11A and 11B  are sectional views, orthogonal to the plasma tubes, each of which shows the schematic configuration of the plasma tube array-type display sub-module according to a third embodiment of the present invention; 
         FIGS. 12A and 12B  are sectional views, orthogonal to the plasma tubes, each of which shows the schematic configuration of the plasma tube array-type display sub-module according to the third embodiment of the present invention, when the address electrode support sheet is provided for every plasma tube; and 
         FIG. 13  is a sectional view, orthogonal to the plasma tubes, which shows the schematic configuration of the plasma tube array-type display sub-module according to a fourth embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A plasma tube array-type display sub-module according to embodiments of the present invention will be described in detail with reference to the drawings. 
     First Embodiment 
       FIGS. 2A and 2B  are sectional views orthogonal to plasma tubes  31 ,  31 , . . . of a plasma tube array. More specifically,  FIG. 2A  is a sectional view showing the case where three plasma tubes  31 ,  31 ,  31  for a color display make one set, and an address electrode support sheet  33  is mounted for every/each set.  FIG. 2B  is a sectional view showing the case where the address electrode support sheet  33  is mounted for each plasma tube  31 . 
     (I) in  FIG. 2A  and (I) in  FIG. 2B  show the state of the plasma tube array that is normally fabricated. Specifically, the plasma tubes  31 ,  31 ,  31  which make one set, are adhered to the address electrodes  32 ,  32 , . . . of the address electrode support sheet  33  via an adhesive layer (first adhesive layer)  38  such as a glue, and to a display electrode support sheet  35  where display electrodes  34 ,  34 , . . . are formed via an adhesive layer (second adhesive layer)  37  such as a glue. The plasma tubes  31 ,  31 ,  31  have respective phosphor layers  36 R,  36 G, and  36 B of red, green, and blue, formed therein. 
     When the address electrode support sheet  33  is cut, a burr  39  might be generated at the end of the address electrode support sheet  33  as illustrated in (II) in  FIG. 2A  and (II) in  FIG. 2B . A warpage might be caused on the address electrode support sheet  33  depending upon humidity, temperature, or the like. (III) in  FIG. 2A  and (III) in  FIG. 2B  show the state of the plasma tube array in the case where the warpage is caused on the address electrode support sheet  33   a . When the warpage is caused, a gap is likely to be formed between the address electrode support sheet  33   a  and the adhesive layer  38 . 
     Further, irregularities might be formed on the surface shape of the address electrode support sheet  33  on the back side even by the difference in the size, such as the diameter of each plasma tube  31 . For example, as shown in (IV) in  FIG. 2A  and (V) in  FIG. 2B , the irregularities are formed on the address electrode support sheet  33  side because a plasma tube  31   a  is larger than the other plasma tubes  31 ,  31 , . . . . When the address electrode support sheet  33  is mounted for every plasma tube  31 , the irregularities may be formed on the surface shape of the address electrode support sheet  33  on the back side, because a plasma tube  31   b  is attached aslant as shown in (IV) in  FIG. 2B . 
     When a plasma tube array-type display sub-module is formed by using the plasma tube array in which the irregularities are formed on the surface shape of the address electrode support sheet  33  on the back side, the irregularities are also formed on the surface shape of the display electrode support sheet  35  on the front side, since a sub-module frame (a back support plate) is made of a hard material.  FIGS. 3A and 3B  are illustrations each of which shows a configuration of the plasma tube array-type display sub-module using the plasma tube array with the irregularities on the surface shape of the address electrode support sheet  33  on the back side. More specifically,  FIG. 3A  shows the case where the sub-module frame or plate  40  is flat and  FIG. 3B  shows the case where the sub-module frame or plate is curved. 
     As shown in  FIG. 3A  and  FIG. 3B , when the plasma tube array with the irregularities formed on the surface shape of the address electrode support sheet  33  on the back side is bonded to a sub-module frame  40  via an adhesive layer  42  such as a glue, the irregularities are also formed on the surface shape of the display electrode support sheet  35  due to the irregularities formed by the burr  39 , the warpage of the address electrode support sheet  33   a , and the difference in size, i.e., the diameter of the tube, of the plasma tube  31   a , with the result that a plurality of separation portions  41 ,  41 , . . . is formed between the adhesive layer  37  of the display electrode support sheet  35  and the plasma tubes  31 ,  31 , . . . . Further, a plurality of gaps  43 ,  43  . . . is formed between the adhesive layer  42 , which is provided between the sub-module frame  40  and the address electrode support sheet  33 , and the plasma tubes  31 ,  31 , . . . . Moreover, residual stress is caused even at the position where the separation does not occur. This entails deterioration of a discharge protection film in the plasma tube  31 , so that electrical characteristic is deteriorated. Accordingly, even when a drive voltage is applied, a desired intensity of an electric field cannot be acquired, which entails a problem that the electrical characteristic is remarkably deteriorated. 
       FIG. 4  is an illustration which shows the configuration of the plasma tube array-type display sub-module using the plasma tube array with the irregularities formed on the surface shape of the address electrode support sheet  33  on the back side, when the address electrode support sheet  33  is provided for every plasma tube  31 . As in  FIGS. 3A and 3B , when the plasma tube array with the irregularities formed on the surface shape of the address electrode support sheet  33  on the back side is bonded to the sub-module frame  40  via the adhesive layer  42  such as a glue, the irregularities are also formed on the surface shape of the display electrode support sheet  35  due to the irregularities formed by the burr  39 , the warpage of the address electrode support sheet  33   a , and the difference in size, i.e., the diameter of the tube, of the plasma tube  31   a , with the result that the plurality of separation portions  41 ,  41 , . . . is formed between the adhesive layer  37  of the display electrode support sheet  35  and the plasma tubes  31 ,  31 , . . . . Further, the plurality of gaps  43 ,  43 , . . . is formed between the adhesive layer  42  and the plasma tubes  31 ,  31 , . . . . 
       FIG. 5  is an illustrative sectional view along the plasma tubes  31 ,  31 , . . . on the side including the address electrode support sheet  32 , which shows the plasma tube array-type display sub-module using the plasma tube array with the irregularities on the surface shape of the address electrode support sheet  33  on the back side. Although the direction is different, as in  FIG. 3A ,  FIG. 3B  and  FIG. 4 , when the plasma tube array with the irregularities formed on the surface shape of the address electrode support sheet  33  on the back side is bonded to the sub-module frame  40  via the adhesive layer  42  such as a glue, the irregularities might also be formed on the surface shape of the display electrode support sheet  35 , and further, a deformed portion  51  where the plasma tube  31  itself deforms due to the irregularities formed by the burr  39 , the warpage of the address electrode support sheet  33 , and the difference in size, i.e., the diameter of the tube, of the plasma tube  31 . By the deformation of the plasma tube  31 , a plurality of gaps  52 ,  52 , . . . is formed between the address electrode support sheet  33  and the sub-module frame  40 , and the gaps  52 ,  52 , . . . thereof may cause noise generated from the plasma tubes  31 ,  31 , . . . . 
     In view of this, the first embodiment is featured in that an intermediate layer made of a hardening resin, e.g., a thermosetting resin, is formed between the sub-module frame  40  and the plasma tube array, and the irregularities formed on the surface shape of the address electrode support sheet  33  on the back side are absorbed during the process of forming the intermediate layer.  FIGS. 6A and 6B  are sectional views, orthogonal to the plasma tubes  31 ,  31 , . . . , each of which shows the schematic configuration of the plasma tube array-type display sub-module according to the first embodiment of the present invention. More specifically,  FIG. 6A  shows an overall configuration of the plasma tube array-type display sub-module including an intermediate layer  60  according to the first embodiment. FIG.  6 B shows the configuration of the intermediate layer  60 . 
     As shown in  FIG. 6A , the plasma tube array is provided so as to be embedded into the intermediate layer  60  which is made of the thermosetting resin and formed on the surface of the sub-module frame  40 . In the state that the plasma tube array is embedded to a predetermined depth in the intermediate layer  60 , heat is applied to cure the intermediate layer  60 , whereby the intermediate layer  60  is formed. As the intermediate layer  60  is formed so as to have the sectional shape as shown in  FIG. 6A , the intermediate layer  60  with the shape along the formed irregularities can be formed even if any irregularities are formed on the surface shape of the address electrode support sheet  33  on the back side. Accordingly, the irregularities, due to the irregularities on the address electrode support sheet  33  on the back side are not formed on the surface shape of the display electrode support sheet  35 . Therefore, the separation portion  41  is not formed between the adhesive layer  37  of the display electrode support sheet  35  and the plasma tubes  31 ,  31 , . . . . Further, the thermosetting resin is filled in the gap  43  in  FIG. 4  (the gap  52  in  FIG. 5 ). It is necessary that the thermosetting resin used for the intermediate layer  60  is more flexible than the plasma tube array before heated to have a shape along any irregularities formed on the surface shape of the address electrode support sheet  33  on the back side. Moreover, it is necessary that the thermosetting resin is more flexible than the plasma tube array even after thermally cured, so that unnecessary force is not applied to the plasma tube array. 
       FIGS. 7A and 7B  are illustrative sectional views along the plasma tubes  31 ,  31 , . . . on the side including the address electrode  32  each of which shows the plasma tube array-type display sub-module according to the first embodiment of the present invention. More specifically,  FIG. 7A  shows an overall configuration of the plasma tube array-type display sub-module including the intermediate layer  60  according to the first embodiment of the present invention.  FIG. 7B  shows the configuration of the intermediate layer  60 . 
     As shown in  FIG. 7A , the plasma tube array is provided so as to be embedded into the intermediate layer  60  which is made of the thermosetting resin and formed on the surface of the sub-module frame  40 . In the state that the plasma tube array is embedded to a predetermined depth in the intermediate layer  60 , heat is applied to cure the intermediate layer  60 , whereby the intermediate layer  60  is formed. Since the intermediate layer  60  is formed so as to have the sectional shape as shown in  FIG. 7B , the plurality of irregularities  71 ,  71 , . . . is absorbed by the intermediate layer  60  with the shape along the irregularities  71 ,  71 , even if a plurality of irregularities  71 ,  71 , . . . is formed on the plasma tube array on the back side of the intermediate layer  60 . Therefore, the surface shape of the display electrode support sheet  35  does not deform along the irregularities  71 ,  71 , . . . , whereby the plasma tube  31  is not deformed. 
     The thickness of the intermediate layer  60  varies depending upon the type of the glue for the adhesive layer  37  that bonds the display electrode support sheet  35  and the plasma tube array, the type of the glue for the adhesive layer  38  that bonds the address electrode support sheet  33  and the plasma tube array, and the material of the intermediate layer  60 . In the first embodiment, the thermosetting resin such as a solvent type acrylic resin, for example, is used for the intermediate layer  60 . It is preferable to use the solvent type acrylic resin for both the adhesive layers  37  and  38  in order to minimize the type of the synthetic resin to use. 
     However, the solvent type acrylic resin might cause a trouble such as a separation by a dissolution or a chemical reaction when the adhesive layers  37 ,  38  are in contact with each other. In view of this, the height of the address electrode support sheet  33 , which is the most proximate to the sub-module frame  40 , of the address electrode support sheets  33 ,  33 , . . . is defined as a limit, and the thermosetting resin is filled to this limit so as to form the intermediate layer  60 . 
       FIGS. 8A and 8B  are sectional views, orthogonal to the plasma tubes  31 ,  31 , . . . each of which shows a schematic configuration of the plasma tube array-type display sub-module according to the first embodiment of the present invention. More specifically,  FIG. 8A  shows the overall configuration of the plasma tube array-type display sub-module including the intermediate layer  60  according to the first embodiment.  FIG. 8B  shows the configuration of the intermediate layer  60 . 
     As shown in  FIG. 8A , the plasma tube array is provided so as to be embedded into the intermediate layer  60  which is made of the thermosetting resin and formed on the surface of the sub-module frame  40 . The intermediate layer  60  is formed in such a manner that the height of the address electrode support sheet  33 , which is the most proximate to the sub-module frame  40 , of the address electrode support sheets  33 ,  33 , . . . is defined as a limit. As the thin intermediate layer  60  is formed so as to have the sectional shape as shown in  FIG. 8B , the intermediate layer  60  with the shape along the formed irregularities can be formed, even if any irregularities are formed on the surface shape of the address electrode support sheet  33  on the back side. Accordingly, the irregularities due to the irregularities on the surface shape of the address electrode support sheet  33  on the back side, are not formed on the surface shape of the display electrode support sheet  35 . Therefore, the separation portion  41  is not formed between the adhesive layer  37  of the display electrode support sheet  35  and the plasma tubes  31 ,  31 , . . . . Further, the thermosetting resin is filled in the gap  43  in  FIG. 4  (the gap  52  in  FIG. 5 ). 
     One type of the synthetic resin is enough and the intermediate layer  60  can be formed with only a minimum amount of the synthetic resin. Therefore, the effective intermediate layer  60  can be formed at low cost. Since the thickness of the intermediate layer  60  is reduced, the intermediate layer  60  and the adhesive layer  38  are not easily brought into contact with each other, even when pressure is applied from the front side of the plasma tube array (the display electrode support sheet  35  side) before the intermediate layer  60  is cured, whereby the intermediate layer  60  can be formed more safely. 
     According to the first embodiment of the present invention, as described above, the intermediate layer  60  with the shape along the formed irregularities can be formed easily, even if any irregularities are formed on the surface shape of the address electrode support sheet  33  on the back side. Therefore, the irregularities due to the irregularities on the surface shape of the address electrode support sheet  33  on the back side, are not formed on the surface shape of the display electrode support sheet  35 . Further, the separation portion  41  between the adhesive layer  37  and the plasma tubes  31 ,  31 , . . . as well as the gap  43  (the gap  52 ) between the adhesive layer  42  and the plasma tubes  31 ,  31 , . . . are not formed. Accordingly, the deterioration in the electrical characteristic in the plasma tube  31  is prevented, and further, a designed voltage is enough for the drive voltage to apply. Consequently, a display device of a large screen with a high image quality can be realized. 
     Second Embodiment 
     The second embodiment is different from the first embodiment in that a thermosetting resin, such as a solventless type epoxy resin, for example, is used for the intermediate layer  60 , and that a thermosetting resin such as a solvent type acrylic resin, for example, is used for the adhesive layers  37  and  38 . The solventless type epoxy resin and the solvent type acrylic resin are not dissolved, and a chemical reaction does not occur between them even when they are brought into contact with each other. Therefore, the intermediate layer  60  can be formed in the region where the intermediate layer  60  can support the plasma tubes  31 ,  31 , . . . . A solventless type acrylic resin may be used for the intermediate layer  60 . 
       FIGS. 9A and 9B  are sectional views, orthogonal to the plasma tubes  31 ,  31 , . . . each of which shows a schematic configuration of the plasma tube array-type display sub-module according to the second embodiment of the present invention. More specifically,  FIG. 9A  shows the overall configuration of the plasma tube array-type display sub-module including the intermediate layer  60  according to the second embodiment.  FIG. 9B  shows the configuration of the intermediate layer  60 . 
     As shown in  FIG. 9A , the plasma tube array is provided so as to be embedded into the intermediate layer  60  which is made of the thermosetting resin and formed on the surface of the sub-module frame  40 . The intermediate layer  60  is formed in such a manner that the thermosetting resin is filled in the display electrode support sheet  35  through the gap between the address electrode support sheets  33 ,  33 , . . . . Since the thick intermediate layer  60  is formed so as to have the sectional shape as shown in  FIG. 9B , the intermediate layer  60  with the shape along the formed irregularities can be formed, even if any irregularities are formed on the surface shape of the address electrode support sheet  33  on the back side. Accordingly, the irregularities due to the irregularities on the address electrode support sheet  33  on the back side, are not formed on the surface shape of the display electrode support sheet  35 . Therefore, the separation portion  41  is not formed between the adhesive layer  37  of the display electrode support sheet  35  and the plasma tubes  31 ,  31 , . . . . Further, the thermosetting resin is filled in the gap  43  in  FIG. 4  (the gap  52  in  FIG. 5 ). 
     The intermediate layer  60  can support respective set of the plasma tubes  31 ,  31 ,  31 , so that the plasma tubes  31 ,  31 , . . . hardly vibrate. Accordingly, this structure can effectively prevent the generation of noise from the plasma tubes  31 ,  31 , . . . . 
       FIGS. 10A and 10B  are sectional views, orthogonal to the plasma tubes  31 ,  31 , . . . , each of which shows the schematic configuration of the plasma tube array-type display sub-module according to the second embodiment of the present invention, when the address electrode support sheet  33  is provided for every plasma tube  31 . More specifically,  FIG. 10A  shows the overall configuration of the plasma tube array-type display sub-module including the intermediate layer  60  according to the second embodiment.  FIG. 10B  shows the configuration of the intermediate layer  60 . 
     As shown in  FIG. 10A , the plasma tube array is provided so as to be embedded into the intermediate layer  60  which is made of the thermosetting resin and formed on the surface of the sub-module frame  40 . The intermediate layer  60  is formed so as to reach the display electrode support sheet  35  in such a manner that the thermosetting resin is filled in the surrounding of each plasma tubes  31  through the gap between the address electrode support sheets  33 ,  33 , . . . . Since the thick intermediate layer  60  is formed so as to have the sectional shape as shown in  FIG. 10B , the intermediate layer  60  with the shape along the formed irregularities can be formed even if any irregularities are formed on the surface shape of the address electrode support sheet  33  on the back side. Accordingly, the irregularities due to the irregularities on the address electrode support sheet  33  on the back side, are not formed on the surface shape of the display electrode support sheet  35 . Therefore, the separation portion  41  is not formed between the adhesive layer  37  of the display electrode support sheet  35  and the plasma tubes  31 ,  31 , . . . . Further, the thermosetting resin is filled in the gap  43  in  FIG. 4  (the gap  52  in  FIG. 5 ). 
     The intermediate layer  60  can support each of the plasma tubes  31 ,  31 , . . . , so that the plasma tubes  31 ,  31 , . . . hardly vibrate. Accordingly, this structure can effectively prevent the generation of noise from the plasma tubes  31 . 
     According to the second embodiment, as described above, even if the adhesive layers  37 ,  38  and the intermediate layer  60  are brought into contact with each other, a chemical reaction does not occur between them, whereby the plasma tube array can be adhered onto the sub-module frame  40  without deteriorating the quality of the plasma tube array. Since the intermediate layer  60  can support each of the plasma tubes  31 ,  31 , . . . so as to fix it at a predetermined position, the generation of a specific noise due to the vibration of the plasma tube  31  can effectively be prevented. 
     Third Embodiment 
     The third embodiment, as in the second embodiment, is different from the first embodiment in that a thermosetting resin, such as a solventless type epoxy resin, for example, is used for the intermediate layer  60 , and that a solvent type acrylic resin, for example, is used for the adhesive layers  37  and  38 . The solventless type epoxy resin and the solvent type acrylic resin are not dissolved, and a chemical reaction does not occur between them even when they are brought into contact with each other. Therefore, the intermediate layer  60  can be formed in the region where the intermediate layer  60  can support the plasma tubes  31 ,  31 , . . . . A solventless type acrylic resin may be used for the intermediate layer  60 . 
     The epoxy resin may be used for the intermediate layer  60 , while a rubber resin such as a silicon may be used for the adhesive layer  38 . Further, the rubber resin such as the silicon may be used for the adhesive layer  37 , and the solvent type acrylic resin may be used for the adhesive layer  37 . In this case, the epoxy resin and the rubber resin are not dissolved, and a chemical reaction does not occur between them even when they are brought into contact with each other. Therefore, the intermediate layer  60  can be formed to have a height enough to support the plasma tubes  31 ,  31 , . . . . 
     On the other hand, when the solvent type acrylic resin is brought into contact with the rubber resin such as the silicon, both are dissolved, or a chemical reaction occurs between them, resulting in entailing a trouble such as a separation. In view of this, the height where the intermediate layer  60  is not in contact with the adhesive layer  37  is defined as a limit, and the thermosetting resin is filled to this limit so as to form the intermediate layer  60 . 
       FIGS. 11A and 11B  are sectional views, orthogonal to the plasma tubes  31 ,  31 , . . . , each of which shows the schematic configuration of the plasma tube array-type display sub-module according to the third embodiment of the present invention, when the address electrode support sheet  33  is provided for every set of the plasma tubes  31 ,  31 ,  31 . More specifically,  FIG. 11A  shows the overall configuration of the plasma tube array-type display sub-module including the intermediate layer  60  according to the third embodiment.  FIG. 11B  shows the configuration of the intermediate layer  60 . 
     As shown in  FIG. 11A , the plasma tube array is provided so as to be embedded into the intermediate layer  60  which is made of the thermosetting resin and formed on the surface of the sub-module frame  40 . The intermediate layer  60  is formed in such a manner that the thermosetting resin is filled in the lower-half surrounding of each the plasma tube  31  through the gap between the address electrode support sheets  33 ,  33 , . . . . Since the thick intermediate layer  60  is formed so as to have the sectional shape as shown in  FIG. 11B , the intermediate layer  60  with the shape along the formed irregularities can be formed, even if any irregularities are formed on the surface shape of the address electrode support sheet  33  on the back side. Accordingly, the irregularities due to the irregularities on the address electrode support sheet  33  on the back side, are not formed on the surface shape of the display electrode support sheet  35 . Therefore, the separation portion  41  is not formed between the adhesive layer  37  of the display electrode support sheet  35  and the plasma tubes  31 ,  31 , . . . . Further, the thermosetting resin is filled in the gap  43  in  FIG. 4  (the gap  52  in  FIG. 5 ). 
     The intermediate layer  60  can support respective set of the plasma tubes  31 ,  31 ,  31 , so that the plasma tubes  31 ,  31 , . . . hardly vibrate. Accordingly, this structure can effectively prevent the generation of noise from the plasma tubes  31 ,  31 , . . . . 
       FIGS. 12A and 12B  are sectional views, orthogonal to the plasma tubes  31 ,  31 , . . . each of which shows the schematic configuration of the plasma tube array-type display sub-module according to the third embodiment of the present invention, when the address electrode support sheet  33  is provided for every plasma tube  31 . More specifically,  FIG. 12A  shows the overall configuration of the plasma tube array-type display sub-module including the intermediate layer  60  according to the third embodiment.  FIG. 12B  shows the configuration of the intermediate layer  60 . 
     As shown in  FIG. 12A , the plasma tube array is provided so as to be embedded into the intermediate layer  60  which is made of the thermosetting resin and formed on the surface of the sub-module frame  40 . The intermediate layer  60  is formed in such a manner that the thermosetting resin is filled in the lower-half surrounding of each plasma tube  31  through the gap between the address electrode support sheets  33 ,  33 , . . . . Since the thick intermediate layer  60  is formed so as to have the sectional shape as shown in  FIG. 12B , the intermediate layer  60  with the shape along the formed irregularities can be formed, even if any irregularities are formed on the surface shape of the address electrode support sheet  33  on the back side. Accordingly, the irregularities due to the irregularities on the address electrode support sheet  33  on the back side are not formed on the display electrode support sheet  35 . Therefore, the separation portion  41  is not formed between the adhesive layer  37  of the display electrode support sheet  35  and the plasma tubes  31 ,  31 , . . . . Further, the thermosetting resin is filled in the gap  43  in  FIG. 4  (the gap  52  in  FIG. 5 ). 
     The intermediate layer  60  can support each of the plasma tubes  31 ,  31 , . . . , so that the plasma tubes  31 ,  31 , . . . hardly vibrate. Accordingly, this structure can effectively prevent the generation of noise from the plasma tubes  31 ,  31 , . . . . Further, the material of the adhesive layer  37  does not matter. Therefore, cost can be reduced by using a less-expensive synthetic resin. 
     As described above, according to the third embodiment, even if the adhesive layer  38  and the intermediate layer  60  are brought into contact with each other, a chemical reaction does not occur between them, whereby the plasma tube array can be adhered onto the sub-module frame  40  without deteriorating the quality of the plasma tube array. Since the intermediate layer  60  can support each of the plasma tubes  31 ,  31 , . . . so as to fix it at a predetermined position, the generation of specific noise due to the vibration of the plasma tubes  31 ,  31 , . . . can effectively be prevented. 
     In the first to third embodiments described above, it is supposed that a separate structure body is used as the sub-module frame. However, the sub-module frame may be made of a material same as that of the intermediate layer  60 . In this case, the intermediate layer  60  can be made of an epoxy resin or an acrylic resin. 
     Fourth Embodiment 
     The configuration of the plasma tube array-type display sub-module according to the fourth embodiment of the present invention is the same as that in the first embodiment. Therefore, the same numerals are given and the detailed description will not be repeated. The fourth embodiment is different from the first embodiment in that a gel-like material with a noise absorbing function is used for the intermediate layer  60  to absorb an abnormal noise generated from the plasma tube array. 
     Specifically, when two plasma tube array-type display sub-modules are joined to each other, each of the address electrode support sheets  33 ,  33 , . . . having the address electrodes  32 ,  32 , . . . formed thereon is bent toward the back side in order not to form a gap between the plasma tube arrays as less as possible. The same is true for the display electrode support sheet  35  having the display electrodes  34 ,  34 , . . . formed thereon. 
     Accordingly, the plasma tubes  31 ,  31 , . . . are arranged extremely proximate to each other. When a drive voltage is applied, the shape of each plasma tube  31  is slightly deformed due to the pressure variation or temperature change inside the plasma tubes  31 ,  31 , . . . . The production precision itself varies of the plasma tubes  31 ,  31 , . . . , wherein the size, i.e., the diameter, of each of the plasma tubes  31 ,  31 , . . . is non-constant. These factors are correlated with each other, resulting in that, depending upon a drive input pattern, resonance occurs with a vibration mode specific to the plasma tube array, and therefore, the abnormal noise is generated from the surface of the plasma tube array. 
     The abnormal noise generated from the surface of the plasma tube array is transmitted through the display electrode support sheet  35 , and emit to a person who sees an image of the display device from the front side. The abnormal noise might cause uncomfortable feeling to person seeing the image. 
     In view of this, in the fourth embodiment, the intermediate layer  60  of the address electrode support sheets  33 ,  33 , . . . on the back side of the plasma tube array is made of a gel-like material with the noise absorbing function, whereby a noise absorbing layer is formed. Further, a hard back support plate  70  that supports the intermediate layer  60  is made of a material with a noise reflecting function, whereby a noise reflection layer is formed.  FIG. 13  is a sectional view, orthogonal to the plasma tubes  31 ,  31 , . . . , which shows the schematic configuration of the plasma tube array-type display sub-module according to the fourth embodiment of the present invention. 
     As shown in  FIG. 13 , the gel-like intermediate layer  60  is formed on the back side of the address electrode support sheets  33 ,  33 , . . . as the noise absorbing layer. The intermediate layer  60  is interposed between the hard back support plate  70  and the address electrode support sheets  33 ,  33 , . . . , wherein the intermediate layer  60  deforms along the surface shape of the address electrode support sheets  33 ,  33 , . . . on the back side. The hard back support plate  70  functions as the noise reflection layer. 
     By virtue of this structure, when the abnormal noise is generated from the surface of the plasma tube array, a certain amount of noise energy is absorbed by the intermediate layer  60 , whereas a certain amount of noise is reflected toward the plasma tube array side by the hard back support plate  70 . Next, a certain amount of noise energy of the noise reflected by the hard back support plate  70  is absorbed again by the intermediate layer  60 , whereby the abnormal noise generated from the surface of the plasma tube array can be reduced. 
     It is preferable that a soft material with a Young&#39;s modulus of 10 to 200 KPa, for example, is used for the intermediate layer  60  which functions as the noise absorbing layer. Examples may include a material that has light transparency, such as silicone gel, polyethylene gel, acrylic gel, urethane gel, acrylic urethane gel, butadiene gel, isoprene gel, butyl gel, styrene butadiene gel, ethylene-vinyl acetate copolymer gel, ethylene-propylene-diene terpolymer gel, fluorine gel, and the like. 
     It is preferable that a hard material with a Young&#39;s modulus of 1000 to 4000 KPa, for example, is used for the back support plate  70  which functions as the noise reflection layer. Examples may include a material that has light transparency and can be used for a polymer film, such as polyethylene terephthalate, polyether sulfone, polystyrene, polyethylene naphthalate, polyarylate, polyether ether ketone, polycarbonate, polyethylene, polypropylene, polyamide such as nylon 6 and the like, polyimide, cellulose resin such as triacetyl cellulose and the like, polyurethane, fluorine resin such as polytetrafluoroethylene and the like, vinyl compound such as polyvinyl chloride and the like, polyacrylic acid, polyacrylic acid ester, polyacrylonitrile, addition polymer such as vinyl compound and the like, polymethacrylate, polymethacrylic acid ester, vinylidene compound such as polyvinylidene chloride and the like, vinylidene fluoride/trifluoroethylene copolymer, vinyl compound or fluorine compound copolymer such as ethylene/vinyl acetate copolymer and the like, polyether such as polyethylene oxide and the like, epoxy resin, polyvinyl alcohol, polyvinyl butyral, or the like. 
     According to the fourth embodiment, the intermediate layer  60  functions as the noise absorbing layer, which can effectively avoid the specific noise generated from the surface of the plasma tube array leaking from the front side of the display device. Accordingly, the display device that does not give uncomfortable feeling to a person seeing an image can be provided. 
     The fourth embodiment is described on the basis of the configuration in the first embodiment. It is needless to say that the same effect can be obtained even with the configurations in the second and third embodiments if the intermediate layer  60  is made of a gel-like material. 
     Various modifications are possible without departing from the scope of the present invention. It is needless to say that, for example, the material for the intermediate layer  60 , the adhesive layers  37  and  38  is not limited to the above-mentioned materials, but can be selected according to how much the intermediate layer  60  is filled.