Abstract:
A display device ( 10 ) including a plurality of gas discharge tubes ( 11 R,  11 G,  11 B) sandwiched between a front support plate ( 31 ) and a rear support plate ( 32 ). The display device further including: a plurality of display electrodes ( 2 ) formed on a surface of the front support plate facing the gas discharge tubes to extend across the axial direction of the gas discharge tubes; and a plurality of signal electrodes ( 3 ) formed on a surface of the rear support plate facing the gas discharge tubes to extend along the longitudinal direction of the gas discharge tubes. The plurality of signal electrodes are divided into a plurality of groups (B 1,  B 2, . . . ,  Ba). Each group includes a predetermined number of signal electrodes. The distance between adjacent ones of the signal electrodes in each group has a first distance. The distance between adjacent ones of said signal electrodes in each group is substantially equal to a first distance (P T ). The distance between the signal electrode at an end of each group of the signal electrodes and the signal electrode at the adjacent end of the adjacent group is substantially equal to a second distance (P G ) that is larger than the first distance.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates generally to a display device, and more particularly to a display device having a plurality of thin elongated gas discharge tubes in parallel for displaying any types of pictures.  
       BACKGROUND ART  
       [0002]     A display device has been proposed, which includes gas discharge tubes disposed side by side, and in which a gas discharge is produced by application of a voltage through external electrodes, whereby light is emitted from phosphors within the tubes. (See Japanese Patent Application Publication JP 2003-86141-A.)  
         [0003]     Such a display device includes: gas discharge tubes, each containing a discharge gas and having a phosphor layer therein, supports contacting and supporting the gas discharge tubes, and a plurality of electrodes disposed on the surfaces of the supports facing the gas discharge tubes for externally applying a voltage to the discharge tubes of the display device to cause a discharge to take place within the discharge tubes to thereby provide picture display.  
       DISCLOSURE OF THE INVENTION  
       [0004]     It is desirable that the precision of the registration of the address or signal electrodes and the gas discharge tubes of such a display device should be as high as possible. However, achievement of such high precision requires complicated manufacturing process, causing the manufacturing cost to increase.  
         [0005]     In order to simplify the process for manufacturing prior art display devices, registration between the address electrodes and the gas discharge tubes was achieved in a simple manner by forming the address electrodes at predetermined intervals on the rear support and arranging the gas discharge tubes on the rear support in such a manner as to make adjacent gas discharge tubes contact with each other. However, dimensions of the gas discharge tubes vary, and hence a cumulative error in the tube width may cause undesirable misregistration between the address electrodes and the gas discharge tubes. On the other hand, if the gas discharge tubes and the address electrodes are accurately registered before bonding them, the number of steps for bonding increases, which increases the manufacturing cost.  
         [0006]     The inventors have recognized that there is a need for achieving registration between the address or signal electrodes and the gas discharge tubes at a low cost.  
         [0007]     An object of this invention is to achieve registration between signal electrodes and gas discharge tubes at a low cost.  
         [0008]     Another object of the invention is to provide disposition of a plurality of gas discharge tubes on a rear support in such a manner as to make it possible to achieve registration between signal electrodes and the gas discharge tubes.  
       SUMMARY OF THE INVENTION  
       [0009]     In accordance with an aspect of the present invention, a display device includes: a plurality of gas discharge tubes sandwiched between a front support plate and a rear support plate; a plurality of display electrodes formed on a surface of the front support plate facing the gas discharge tubes to extend across the axial direction of the gas discharge tubes; and a plurality of signal electrodes formed on a surface of the rear support plate facing the gas discharge tubes to extend along the longitudinal direction of the gas discharge tubes. The plurality of signal electrodes are divided into a plurality of groups, each including a predetermined number of signal electrodes. The distance between adjacent ones of the signal electrodes in each group is substantially equal to a first distance. The distance between the signal electrode at an end of each group of the signal electrodes and the signal electrode at the adjacent end of the adjacent group being substantially equal to a second distance that is larger than the first distance.  
         [0010]     In accordance with another aspect of the invention, a display device includes: a plurality of groups of gas discharge tubes disposed in parallel between a front support plate and a rear support plate; the front support plate having a first plurality of electrodes extending substantially in parallel disposed on a surface of the front support plate facing the gas discharge tubes. The rear support plate having a second plurality of electrodes extending substantially in parallel are disposed on a surface of the rear support plate facing the gas discharge tubes, the plurality of groups of gas discharge tubes being disposed respectively in association with the second plurality of electrodes. The gas discharge tubes are disposed in such a manner that the adjacent gas discharge tubes in each group are substantially in contact with each other, and that the gas discharge tube at an end of each group of the gas discharge tubes and the gas discharge tube at the adjacent end of the adjacent group are spaced from each other.  
         [0011]     The invention also relates to a method of manufacturing the display device as described above.  
         [0012]     According to the invention, a display device including a rear support allows registration between its signal electrodes and gas discharge tubes at a low cost. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  shows an example of the structure of part of a large display device, in accordance with an embodiment of the present invention;  
         [0014]      FIG. 2A  is a partial enlarged plan view of the gas discharge tube in the vicinity of the pair of display electrodes, and  FIG. 2B  is a cross-sectional view of the gas discharge tube along a line  3 B- 3 B in  FIG. 2A ;  
         [0015]      FIG. 3  is useful for explaining how misregistration of address or signal electrodes formed on a rear support and the gas discharge tubes in a prior art display device can be generated;  
         [0016]      FIGS. 4A and 4B  are front and side views of a display device in accordance with an embodiment of the invention, which includes a plurality of blocks of gas discharge tubes;  
         [0017]      FIGS. 5A and 5B  show an example of modification of the embodiment shown in  FIGS. 4A and 4B , and are front and side views, respectively, of a display device in accordance with another embodiment of the invention, which includes the plurality of blocks of the gas discharge tubes disposed on a plurality of rear support substrates;  
         [0018]      FIGS. 6A and 6B  show a modification of the embodiment shown in  FIGS. 4A and 4B , and are front and side views, respectively, of a display device in accordance with a further embodiment of the invention, which includes a plurality of blocks of gas discharge tubes;  
         [0019]      FIGS. 7A and 7B  are front and side views of a display device in accordance with a still further embodiment of the invention, which includes a plurality of blocks of gas discharge tubes disposed on a plurality of rear support substrates; and  
         [0020]      FIGS. 8A and 8B  illustrate how the brightness changes in the vicinity of a block dividing line between the adjacent blocks, adjacent to which different color gas discharge tubes are disposed. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0021]     The invention will be described with reference to the accompanying drawings. Throughout the drawings, similar symbols and numerals indicate similar items and functions.  
         [0022]      FIG. 1  shows an example of the structure of part of a large display device  10 , in accordance with an embodiment of the present invention. In  FIG. 1 , the display device  10  includes a plurality of transparent thin elongated gas discharge tubes  11 R,  11 G,  11 B,  12 R,  12 G,  12 B, . . . , disposed substantially in parallel, a front support  31  comprised of a transparent, front support sheet or thin plate, a rear support  32  comprised of a transparent or opaque, rear support sheet or thin plate, a plurality of pairs of display electrodes or main electrodes  2 , and a plurality of signal or address electrodes  3 . The front support  31  and the rear support  32  are made of a material such as elastic PET film, glass or the like. It is desirable for the rear support  32  to be black or dark in color itself or to have a separate black sheet bonded to its front or rear surface in order to provide enhanced contrast in picture display.  
         [0023]     Typically, phosphor support members having respective red, green and blue (R, G, B) phosphor layers formed or deposited thereon are inserted into the interior discharge spaces of the thin gas discharge tubes  11 R,  11 G,  11 B,  12 R,  12 G,  12 B, . . . , respectively. Discharge gas is introduced into the interior discharge space of each gas discharge tube, and the gas discharge tube is sealed at its opposite ends. Alternatively, the phosphor layer may be formed or deposited on the inner surface of an associated gas discharge tube without using the support member. The signal electrodes  3  are formed on the rear support sheet  32  and extend along the longitudinal direction of the respective discharge tubes  11 R,  11 G,  11 B, . . . . The pairs of display electrodes  2  are formed on the front support sheet  31  and extend in the direction crossing the signal electrodes  3 . A distance providing a non-discharging region or non-discharging gap is provided between each pair of display electrodes  2  and an adjacent pair of display electrodes  2 .  
         [0024]     The signal electrodes  3  and the pairs of display electrodes  2  are brought into intimately contact respectively with the lower and upper peripheral surfaces of the gas discharge tubes  11 R,  11 G,  11 B, . . . , when the display device  10  is assembled. In order to provide better contact, an electrically conductive adhesive may be placed between the display electrodes and the gas discharge tubes.  
         [0025]     In plan view of the display device  10  seen from the front side, the intersections of the signal electrodes  3  and the pairs of display electrodes  2  provide unit light-emitting regions. Display is provided by using either one electrode of each pair of display electrodes  2  as a scanning electrode, generating a selection discharge at the intersection of the scanning electrode with the signal electrode  3  to thereby select a light-emitting region, and generating a display discharge between the pair of display electrodes  2  using the wall charge formed by the selection discharge on the region of the inner tube surface at the selected region, which, in turn, causes the associated phosphor layer to emit light. The selection discharge is an opposed discharge generated within each gas discharge tube  11 R,  11 G,  11 B, . . . between the vertically opposing scan electrode and the signal electrode  3 . The display discharge is a surface discharge generated within each gas discharge tube  11 R,  11 G,  11 B, . . . between the two display electrodes of each pair of display electrodes disposed in parallel in a plane.  
         [0026]      FIG. 2A  is a partial enlarged plan view of the gas discharge tube  11  in the vicinity of the pair of display electrodes  2 .  FIG. 2B  is a cross-sectional view of the gas discharge tube  11  along a line  3 B- 3 B in  FIG. 2A . In  FIGS. 2A and 2B , an electron emissive film  5  of MgO is formed on the inner surface of the gas discharge tube  11 , and a support member  6  with a phosphor layer  4  formed thereon is disposed within the gas discharge tube  11 .  
         [0027]     As described above, the gas discharge tube  11  is arranged such that the phosphor layer  4  is caused to emit light through discharge by the plurality of pairs of display electrodes  2  disposed in contact with the tube outer wall surface, whereby a number of light-emitting points (display portions) can be provided in the single tube. The gas discharge tube  11  is formed of a transparent insulating material, e.g. borosilicate glass, and, typically, has a tube diameter of 2 mm or smaller and a tube length of 300 mm or larger.  
         [0028]     The support member  6  is formed of a transparent insulating material, e.g. borosilicate glass, and is a member separate from the tubular envelope (glass tube) of the gas discharge tube  11 , and has the phosphor layer  4  formed thereon. The support member  6  may be disposed within the glass tube by applying a paste of phosphor over the support member  6  outside the glass tube and then baking the phosphor paste to form the phosphor layer  4  on the support member  6 , before inserting the support member  6  into the glass tube. As the phosphor paste, a desired one of various phosphor pastes known in this technical field may be employed.  
         [0029]     The pair of display electrodes  2  and the signal electrode  3  can generate discharges in the discharge gas within the tube by applying voltages between them. The electrode structure of the gas discharge tube  11  shown in  FIGS. 2A and 2B  is such that the three electrodes are disposed in one light-emitting region, and that the discharge between the pair of display electrodes generates a discharge for display. However, the electrode structure is not limited to such a structure. A display discharge may be generated between the display electrode  2  and the signal electrode  3 . In other words, an electrode structure of a type employing a single display electrode may be employed instead of each pair of display electrodes  2 , in which the single display electrode  2  is used as a scanning electrode so that a selection discharge and a display discharge (opposed discharge) are generated between the single display electrode  2  and the signal electrode  3 .  
         [0030]     The electron emissive film  5  emits charged particles, when it is bombarded with the discharge gas having energy above a given value. When a voltage is applied between the pair of display electrodes  2 , the discharge gas contained in the tube is excited. The phosphor layer  4  emits visible light by converting thereinto vacuum ultraviolet radiation generated in the de-excitation process of the excited rare gas atoms.  
         [0031]      FIG. 3  is useful for explaining how misregistration of the address or signal electrodes  3  formed on the rear support  32  and the gas discharge tubes  11  in a prior art display device can be generated. When the plurality of gas discharge tubes  11  are disposed on the rear support  32  with the plurality of address or signal electrodes  3  formed thereon at predetermined intervals, e.g. at intervals equal to an ordinary tube diameter of the gas discharge tubes  11 , undesirable misregistration between the address electrodes  3  and the gas discharge tubes  11  may be generated due to a cumulative error in tube width or tube diameter of the gas discharge tubes  11  because of variations in dimensions of the gas discharge tubes  11  from tube to tube. Typically, the variation in tube width is about 1% of the tube diameter. For example, for the tube width of 1 mm, there is an error of about +0.005 mm or 0.01 mm. Undesirable misregistration between the address electrodes  3  and the gas discharge tubes  11  is seen in the center part of  FIG. 3 .  
         [0032]      FIGS. 4A and 4B  are front and side views of a display device  10  in accordance with an embodiment of the invention. The display device  10  includes a plurality of blocks B 1 , B 2 , . . . , Ba of gas discharge tubes ( 11 R,  11 G,  11 B,  12 R,  12 G,  12 B), . . . , and ( 17 R,  17 G,  17 B,  18 R,  18 G,  28 B).  
         [0033]     As shown in  FIGS. 4A and 4B , a plurality of blocks of signal electrodes  3  are formed on a rear support  32 . Each block of signal electrodes includes 3× a  signal electrodes  3 , where the number  3  represents the number of primary colors R, G and B, and  a  presents a positive integer. The number  a  is preferably 3 or 4. In the illustrated embodiment, it is assumed that the number  a  is two (2). The distance between adjacent ones of the signal electrodes  3  in each block has a pitch P T , which is, for example, 1.0 mm. The pitch P T  is selected to be equal to or may be slightly larger than an average width or tube diameter of the gas discharge tubes. The distance P G  between two adjacent ones of the signal electrodes of any two respective adjacent ones of the blocks (between the blocks  301  and  302 , between  303  and  304 , . . . , and between  307  and  308 ) is selected to be slightly larger than the pitch P T , i.e. P G (&gt;P T ). For example, for the tube widths having an error E, the distance P G  is determined to have a fixed value within a range of from P T ×(1+2aE) to P T ×(1+3aE). For example, for the pitch P T  and tube width being 1.0 mm, the error in tube width of the discharge tubes being 1%, and the number of the gas discharge tubes in one block being twelve (12) (i.e.  a =4), the distance P G  is a value within a range of from 1.09 mm to 1.12 mm. Each one block of discharge tubes ( 11 R,  11 G, . . . ,  12 B), . . . , or ( 17 R,  17 G, . . . ,  18 B) includes the number,  a , of sets of gas discharge tubes, in which each one set includes three gas discharge tubes respectively emitting light of the R, G and B primary colors. In other words, each one block of discharge tubes is formed by 3× a  gas discharge tubes, which are disposed in contact with each other on the signal electrodes  3  of the associated block.  
         [0034]     With the above-described arrangement in which the plurality of signal electrodes  3  formed on the rear support  32  are divided into the blocks B 1 , B 2 , . . . , Ba, with the distance P G  between two adjacent ones of the signal electrodes in any two respective adjacent ones of the blocks (between  301  and  302 , between  303  and  304 , between  307  and  308 ) determined to be larger than the distance P T  between adjacent ones of the signal electrodes  3  in each block, the cumulative miregistrations between the signal electrodes  3  and the gas discharge tubes ( 11 R, . . . ,  12 B) in a block can be absorbed by the distance P G  between the signal electrode of that block and the adjacent signal electrode of the other block adjacent to that block (between the blocks  301  and  302 , between  303  and  304 , . . . , or between  307  and  308 ). In this way, irregular intervals Gb are disposed between the gas discharge tubes, between  12 B and  13 R, between  14 B and  15 R, . . . , and between  16 B and  17 R of the adjacent blocks. Accordingly, there is no undesirable magnitude of misregistrations between the signal electrodes  3  and the gas discharge tubes  11 R,  11 G, . . . ,  18 B in the display device  10 .  
         [0035]     For assembling the display device  10 , the rear support  32 , on which the signal electrodes  3  are formed, is prepared such that the distance (or pitch) between the adjacent signal electrodes  3  within a block differs from the distance (or pitch) between two adjacent ones of the signal electrodes at the respective adjacent ends of any two respective adjacent ones of the blocks, and then the blocks of gas discharge tubes are disposed on the rear support  32 , in such a manner that the gas discharge tubes ( 11 R, . . . ,  12 B), . . . , or ( 17 R, . . . ,  18 B) of each block are disposed in contact with each other, being registered with respect to either one of the two signal electrodes at the opposite ends of that block. In this manner, the display device  10  can be manufactured with ease.  
         [0036]      FIGS. 5A and 5B  show an example of modification of the embodiment shown in  FIGS. 4A and 4B , and are front and side views, respectively, of a display device  102  in accordance with another embodiment of the invention. The display device  102  includes the plurality of blocks B 1 , B 2 , . . . , Ba of the gas discharge tubes ( 11 R,  11 G,  1 B,  12 R,  12 G,  12 B), . . . , and ( 17 R,  17 G,  17 B,  18 R,  18 G,  18 B) disposed on a plurality of rear support substrates or base plates  321 ,  322 , . . . ,  328 .  
         [0037]     In  FIGS. 5A and 5B , the rear support  32  is divided along dividing lines D between several pairs of adjacent signal electrodes of the respective adjacent blocks (between the blocks  301  and  302 , between  303  and  304 , . . . , and between  307  and  308 ), into the plurality of block substrates or base plates  321 ,  322 , . . . , and  328 . A plurality of signal electrodes  3  in the block B 1 , B 2 , or Ba are disposed on the corresponding rear support substrate  321 ,  322 , . . . , or  328 . The structure of the remainder of the display device  102  is similar to that of the display device  10  shown in  FIGS. 4A and 4B . In other words, the rear support  32  of this embodiment is formed of a plurality of divided, separate rear supports  321 ,  322 , . . . , and  328 , and one block of 3× a  signal electrodes  3  is formed on each of the plurality of separate, rear supports  321 ,  322 , . . . , and  328 .  
         [0038]     Each block B 1 , B 2 , . . . , or Ba of the display device  102  is formed of a combination of the rear support substrate  321 ,  322 , . . . , or  328  with an associated group of gas discharge tubes ( 11 R, . . . ,  12 B), . . . , or ( 17 R, . . . ,  18 B). The respective blocks B 1 , B 2 , . . . , and Ba have the same dimensions, shape and configuration.  
         [0039]     Similarly to the above-described embodiment, the cumulative misregistrations between the signal electrodes  3  and the gas discharge tubes ( 11 R, . . . ,  12 B), or ( 17 R, . . . ,  18 B) in each block is absorbed by the distance P G  between the signal electrode of that block and the adjacent electrode of the other block adjacent to that block (between the blocks  301  and  302 , between  303  and  304 , . . . , or between  307  and  308 ).  
         [0040]     For assembling the display device  102 , each group of the adjacent gas discharge tubes ( 11 R, . . . ,  12 B), . . . , or ( 17 R, . . . ,  18 B) are disposed in contact with each other and bonded together on the signal electrodes  3  of the corresponding block B 1 , B 2 , . . . , or Ba on the corresponding rear support substrate  321 ,  322 , . . . , or  328 , and then the plurality of blocks comprised of the respective support substrates  321 ,  322 , . . . , and  328  of the substrate  32  with the disposed gas discharge tubes ( 11 R, . . . ,  12 B), . . . , and ( 17 R, . . . ,  18 B) are combined into the one display device  102 . In this way, the display device  102  is manufactured easily.  
         [0041]      FIGS. 6A and 6B  show a modification of the embodiment shown in  FIGS. 4A and 4B , and are front and side views, respectively, of a display device  104  in accordance with a further embodiment of the invention. The display device  104  includes the plurality of blocks of gas discharge tubes ( 11 R,  11 G,  11 B,  12 R,  12 G,  12 B), and ( 17 R,  17 G,  17 B,  18 R,  18 G,  18 B).  
         [0042]     In  FIGS. 6A and 6B , ribs  341 ,  342 , . . . ,  348  are formed along the dividing lines extending through the midpoints between respective adjacent blocks, i.e. between several respective adjacent signal electrodes, (between the blocks  301  and  302 , between  303  and  304 , between  307  and  308 ) of the adjacent blocks B 1 , B 2 , . . . , Ba on the rear support  32 . Each of the ribs  341 ,  342 ,  348  has a height H smaller than the radius or a half of the height of the gas discharge tube measured perpendicularly to the display screen. For example, for the tube diameter of 1.0 mm, the height H has a fixed value in the range of from 0.2 mm to 0.3 mm. The ribs  341 ,  342 , . . . ,  348  are black or dark in color, or at least their top surfaces are preferably black or dark in color. The structure of the remainder of the display device  104  is similar to that of the display device  10  shown in  FIGS. 4A and 4B .  
         [0043]     Similarly to the embodiments described above, the cumulative error in misregistrations between the plural electrodes  3  and the gas discharge tubes ( 11 R,  12 B), . . . , or ( 17 R, . . . ,  18 B) in a block is absorbed by the distance P G  between the signal electrode of that block and the adjacent signal electrode of the other block adjacent to that block.  
         [0044]     For assembling the display device  104 , each group of the adjacent gas discharge tubes ( 11 R, . . . ,  12 B), or ( 17 R, . . . ,  18 B) are disposed in contact with each other and bonded together on the respective ones of the signal electrodes  3  in the corresponding one of the blocks B 1 , B 2 , . . . , and Ba on the rear support  32 , by using the opposite steps formed between the blocks B 1 , B 2 , Ba of signal electrodes  3  on the rear support  32  and the ribs  341 ,  342 , . . . ,  348 . In this manner, the display device  104  can be manufactured easily.  
         [0045]     The ribs  341 ,  342 , . . . ,  348  may be bonded onto the rear support  32  by means of an adhesive. Alternatively, the rear support  32  with the ribs  341 ,  342 , . . . ,  348  may be formed by masking rib portions of a surface of an unprocessed substrate and etching away the unmasked portions.  
         [0046]      FIGS. 7A and 7B  show a modification of the display device shown in  FIGS. 6A and 6B , and are front and side views, respectively, of a display device  106  in accordance with a still further embodiment of the invention. The display device  106  includes the plurality of blocks B 1 , B 2 , . . . , Ba of the gas discharge tubes ( 11 R,  11 G,  11 B,  12 R,  12 G,  12 B), . . . , and ( 17 R,  17 G,  17 B,  18 R,  18 G,  18 B) disposed on a plurality of rear support substrates  321 ,  322 , . . . ,  328 .  
         [0047]     In  FIGS. 7A and 7B , the rear support  32  is divided into the plurality of rear support substrates  321 ,  322 , . . . ,  328  along dividing lines D′ extending along longitudinally extending side end surfaces of ribs  341 ,  342 , . . . ,  348 , which ribs are located on the dividing lines between adjacent ones of the blocks B 1 , B 2 , . . . , Ba of the signal electrodes (between the blocks  301  and  302 , between  303  and  304 , . . . , between  307  and  308 ) on the rear support  32 . Each of the blocks B 1 , B 2 , . . . , Ba of the plurality of signal electrodes  3  is disposed on the associated rear support substrate  321 ,  322 , . . . , or  328 . The structure of the remainder of the display device  106  is similar to that of the display device  104  shown in  FIGS. 6A and 6B .  
         [0048]     Each block B 1 , B 2 , . . . , or Ba of the display device  106  is formed by a combination of the rear support substrate  321 ,  322 , . . . , or  328  with its corresponding group of gas discharge tubes ( 11 R, . . . ,  12 B), . . . , ( 17 R,  18 B). The blocks B 1 , B 2 , . . . , and Ba have the same dimensions, shape and configuration.  
         [0049]     Similarly to the embodiments described above, the cumulative misregistrations between the signal electrodes  3  and the gas discharge tubes ( 11 R, . . . ,  12 B), or ( 17 R, . . . ,  18 B) in each block can be absorbed by the distance P G  between the signal electrode in that block and the adjacent signal electrode of the other block adjacent to that block (i.e. between the blocks  301  and  302 , between  303  and  304 , or between  307  and  308 ).  
         [0050]     For assembling the display device  106 , each group of adjacent gas discharge tubes ( 11 R, . . . ,  12 B), or ( 17 R, . . . ,  18 B) are disposed in contact with each other and bonded together on the signal electrodes  3  in the corresponding block B 1 , B 2 , . . . , or Ba on the corresponding rear support substrate  321 ,  322 , . . . , or  328 , by using the opposite steps formed between the blocks B 1 , B 2 , . . . , and Ba of signal electrodes  3  on the rear support substrates  321 ,  322 , . . . , and  328  and the ribs  341 ,  342 , . . . ,  348 . After that, the plurality of blocks comprised of the respective rear support substrates  321 ,  322 , . . . , and  328  with the disposed gas discharge tubes ( 11 R, . . . ,  12 B), and ( 17 R, . . . ,  18   b ) are combined together to form the one display device  106 . In this manner, the display device  106  can be manufactured easily.  
         [0051]      FIGS. 8A and 8B  illustrate how the brightness changes in the vicinity of a block dividing line between the adjacent blocks, adjacent to which different color gas discharge tubes are disposed.  
         [0052]     In  FIG. 8A , a green-emitting (G) gas discharge tube with a relatively high brightness, and a blue-emitting (B) gas discharge tube with a relatively low brightness are disposed on respective opposite sides of a dividing line B, where there is a gap Gb between the gas discharge tubes. In this case, the brightness at the gap Gb is the lowest of the three, and hence the brightness change is large in the vicinity of the dividing line B, resulting in large difference in brightness. In this case, the presence of the dark gaps Gb in a picture on the display device  10  is noticeable.  
         [0053]     In  FIG. 8B , a blue-emitting (B) gas discharge tube with a relatively low brightness, and a red-emitting (R) gas discharge tube with a relatively low brightness are disposed on respective opposite sides of a dividing line B, where there is a gap Gb between the gas discharge tubes. In this case, the brightness change in the vicinity of the dividing line B is small, resulting in small brightness difference. Thus, the arrangement of R and B gas discharge tubes with the relatively low brightness on the respective opposite sides of the dividing line B as shown in  FIG. 8B  makes the dark gap Gb hardly noticed in a picture on the display device  10 . Thus it is desirable to arrange the gas discharge tubes as shown in  FIG. 8B . For this reason, the arrangement shown in  FIG. 8B  is employed in the above-described embodiments.  
         [0054]     The above-described embodiments are only typical examples, and their combination, modifications and variations are apparent to those skilled in the art. It should be noted that those skilled in the art can make various modifications to the above-described embodiments without departing from the principle of the invention and the accompanying claims.