Gas discharging type display panel and manufacturing method thereof

Abstract: A partition member for a gas discharge display panel having a front substrate with at least one main discharge electrode spaced from a back substrate having at least one auxiliary discharge electrode so as to delimit a gap therebetween. The partition member is adapted to extend substantially parallel to and between the front and back substrates for forming a main discharge space on a front substrate side and an auxiliary discharge space on a back substrate side, the partition member being a metal material member. A gas discharge display panel incorporates the partition member and a system is provided for driving the gas discharge display panel. Also, a manufacturing method is provided for the partition member and gas discharge display panel.

Description: CROSS REFERENCE TO RELATED APPLICATIONS This application is related to copending U.S. application Serial No. 08/525,975, entitled Gas Discharge Display Panel, filed September 7, 1995 and copending U.S. application Serial No. 08/744,759, entitled Plasma Display Panel Driving System and Method, filed November 6, 1996. BACKGROUND OF THE INVENTION The present invention relates to a gas discharging display panel such as a plasma display panel and a manufacturing method and, more particularly, to an AC-driven gas discharging type display panel suitable for color display and capable of providing a high accuracy and high contrast display and which is inexpensive. A gas discharging display panel such as a plasma display has such features that a view angle is wide, the display is easy to see because of self emission, and it can be fabricated with a reduced thickness, which is utilized as a display device for OA (office automation) equipments, as well as expected for application uses such as high quality television receivers. The gas discharging type display panel is generally classified into a DC driven type and an Ac driven type. Among them, the AC driven type panel has a memory function by the effect of a dielectric layer covering an electrode and has high luminosity. Further, with application of a protective film, a working life endurable to practical use can be obtained even also for the AC driven type in recent years, and it is put to practical use for example, in multipurpose video monitors. Fig. 4 shows a perspective view of a portion of a plasma display panel which is presently used. The gas discharging type color display panel comprises a back substrate 2 and a front substrate 1 opposed to each other. The back substrate 2 has barrier ribs 3a for maintaining a gap with the front substrate 1 constant, and the front substrate 1 and the back substrate 2 are connected by way of the barrier ribs 3a. In Fig. 4, the front substrate 1 and the barrier ribs 3a of the back substrate 2 are separately shown for ease of viewing. The front substrate 1 has a structure including display electrodes (transparent electrode) 5, buss electrodes 6 made of a metal conductor, an insulator layer 7a and an MgO film (protective film) 8a which are formed on a front glass plate 4a. The back substrate 2 has a structure including address electrodes 9, barrier ribs 3a and a fluorescent layer 14 which are formed on a back glass plate 4b. A discharging space 3f is formed between the front substrate 1 and the back substrate 2 by disposing and appending the front substrate 1 and the back substrate 2 in parallel with each other such that respective surfaces formed with the electrodes are opposed to each other. The display electrodes 5 and the address electrodes 9 are made orthogonal to each other by way of the discharging space 3f. Fig. 5(a) - (c) and Fig. 6 show cross sectional views of the gas discharging type display panel of Fig. 4. Fig. 5(a) is a cross sectional view when cutting a portion of the display panel along a plane parallel with the address electrodes 9 and vertical to the surface of the substrates 1, 2. Fig. 5(b) is a cross sectional view at a position A in Fig. 5(a) and the cutting plane is vertical to the address electrodes 9 and vertical to the surface of the substrates 1, 2. Fig. 5(c) is a cross sectional view at a position B in Fig. 5(a) and the cutting plane is vertical to the address electrodes 9 and vertical to the surface of the substrates 1, 2. In Fig. 5(a) - (c), only the cross section is shown for making the drawing easy to view while the constitution which may be seen at the bottom of the drawing paper is not illustrated. Further, Fig. 6 shows a cross sectional view along a plane shown by C in Fig. 5(a). As shown in Fig. 5(b) and Fig. 5(c), a display cell (also referred to as a discharging cell) is formed between both of substrates 1 and 2 on every set of the transparent electrodes 5a and 5b, and a discharging space 3f is formed by both of the substrates 1, 2 and the barrier ribs 3a. A fluorescent film 14 is formed at the inside of the display cell. Further, discharge gas is sealed in the space 3f in the cell. In the display panel, as shown in Fig. 6, the barrier ribs 3a are in the form of parallel rods, and the discharging space 3f of the cell is continuous laterally (or longitudinally) and is not partitioned by the barrier ribs 3a. When an AC voltage is applied between the electrodes 5, 6 of the front substrate 1 and the address electrodes 9 formed to the back substrate 2, auxiliary discharging is generated in each of the cells 3f formed by the front substrate 1, the back substrate 2 and the barrier rib 3a. When AC voltage is applied between the parallel electrodes 5a, 6a and the electrodes 5b, 6b formed to the front substrate 1 on each of the cells by utilizing the auxiliary discharging, main discharge is generated. Ultraviolet rays caused by the main discharging causes the fluorescent body 14 coated in the cell to emit light. The display by the display panel is conducted by light from the fluorescent body 14 observed through the front substrate 1. An example of the gas discharging type display device shown in Figs. 4-6 is described in Flat Panel Display (1994 (edited by Nikkei Microdevice, 1993), page 198 - 201). As a method of manufacturing such a gas discharging type color display panel, the method explained below is known. At first, a pair of transparent substrates are provided. As the substrate used for the gas discharging color display panel, a soda glass (soda lime glass) plate having a strain point at about 450°C is generally used. After printing an electrode paste to a predetermined pattern by a thick film printing method to one of the glass substrates (back substrate) and drying the paste at 100 - 150°C, it is baked at 500 - 600°C. Then, for forming a display cell as a picture element, a barrier rib-forming paste is printed in a predetermined pattern by a thick film printing method on the surface of the back electrode formed with the electrode pattern and dried at 100 - 150°C. This forms a number of cells arranged in a matrix on the back substrate. A thick film thickness (for example, 160 to 200 µm) is required for the barrier rib in order to ensure a sufficient discharging space and such a thickness can not be obtained by use of the thick film printing method only once. Accordingly, printing and drying of the barrier rib-forming paste are carried out a plurality of times. To the interior of the cells formed by the barrier ribs, red, blue and green pastes for the fluorescent body are printed in a predetermined pattern by a thick film printing method and dried at 100 to 150°C followed by sintering at 500 - 600°C. Thus, a back electrode formed with a display cell can be obtained. A vapor deposition film of a transparent conductor, for example, ITO (indium tin oxide) is formed on the other of the glass substrates (front substrate glass plate), which is patterned to form a number of electrode patterns in parallel with each other such that two electrodes parallel with the row of the cells are disposed on every cells. Then, a buss electrode is formed to each of the electrode portions of the pattern for reducing the resistivity of the electrode. After printing a dielectric paste in a predetermined pattern on the surface formed with the electrodes by a thick film printing method and drying the same at 100 - 150°C, it is sintered at 500 - 600°C. Further, an MgO film is formed to the surface of the resultant dielectric film by an EB (electron beam) vapor deposition method. Thus, a front substrate formed with transparent electrodes can be obtained. Then, the front substrate and the back substrate are aligned with the surface of the front substrate formed with the MgO film and the surface of the back substrate formed with the cell being opposed to each other, and edge portions of both of the substrates are covered with lead glass for sealing, and heated at about 450°C to effect sealing between both of the substrates. Then, air in the gap surrounded with both of the substrates and the sealed portion is evacuated from an evacuation pipe and a discharge gas is entered into the gap by way of the evacuation pipe. Finally, the evacuation pipe is chipped off to seal the discharge gas. With the procedures described above, the gas discharging type color display panel is prepared. In the foregoing explanation, although the barrier ribs are formed to the back substrate, the barrier ribs may be formed on the front substrate or formed on both of the front substrate and the back substrate depending on the design of the display panel. Further, the electrode or the MgO film may sometimes be formed by a thick film printing method. The method of manufacturing the display panel described above has a merit capable of manufacturing a display panel relatively easily since the barrier ribs, electrodes, the fluorescent body, etc. are formed by the thick film printing method. As described above, in the gas discharging type display panel of the prior art, since auxiliary discharging and main discharging are conducted in an identical discharging space, light emission is caused by the auxiliary discharging also in an area where the main discharging is not conducted, so as to bring about a problem that the display panel is not capable of obtaining a sufficient contrast. If sufficient contrast is not obtained, high speed time divisional control has to be applied by a complicated driving method in order to obtain sufficient gradation for full color display. Thus, it is desirable to obtain a sufficient contrast by the structure of the gas discharging display panel. Further, the thickness of the barrier rib has to be made as large as from 160 to 200 µm in order to ensure a sufficient discharging space, but such thickness can not be obtained by only one time of the thick film printing so that the manufacturing method adopted so far provides the required thickness by repeating printing and drying of the paste for several times. However, with such a procedure, the manufacturing step is made lengthy and since alignment is conducted on every printing, the yield is worsened. In view of the above, it is considered to dispose a partition wall substrate as an integral part of a partition wall having penetration apertures as a discharging conduction path and barrier ribs and put the partition wall substrate between the front substrate and the back substrate. If the space in the display cell is separated by the partition wall into an auxiliary discharging space and a main discharging space, since light caused by the auxiliary discharging can be shielded, the contrast is increased. Further, if the partition wall substrate having the partition wall and the barrier ribs is manufactured by integral shaping, for example, by a sand blasting method of a glass or ceramic plate as an insulator, since this can be handled as one part, no accurate alignment is required as in the case of forming the barrier ribs with the thick film printing. However, in the methods described above, since the substrate such as of ceramics requiring difficult fabrication has to be fabricated into a complex shape, the number of steps is increased to increase the cost. In EP 0 123 496 A2, a gas discharge display panel is described (as well as a method to make it) which includes a gas-filled envelope made up of an insulating base plate and a glass face plate, which are hermetically sealed together. In and on the base plate, a plurality of scan anode and cathode electrodes are seated. The scan cathodes are disposed transverse to the scan anodes, and each crossing of a scan cathode of a scan anode defines a scanning cell. A reset cathode electrode crosses each scan anode, thereby forming a plurality of reset cells. These reset cells are turned on or energized at the beginning of each scanning cycle, and they expedite the turn-on of the first column of scanning cells associated with the first cathode. On the face plate, an A.C. electrode is seated. Between the face and the base plate, an electrode in the form of a thin metal plate is disposed. This metal plate operates with the A.C. electrode on the face plate and produces glow discharge between them and produces excited particles. These excited particles are available to the reset cathode and assist the firing of the column of reset cells. In US patent 4,315,259, the same gas discharge display panel is described. In addition, a driving system for applying D.C. voltages and A.C. voltages, respectively, to the different electrode is disclosed. EP 0 004 549 A1 discloses a glass discharge display panel which includes a top and a base plate and an isolating plate with three groups of electrodes. Between the first and second group of these electrodes, an auxiliary discharging takes place, and between the second and the third group of these electrodes, a main discharging takes place. The auxiliary discharge space and the main discharge space are separated by the second group of electrodes wherein these two spaces are connected through holes in the electrodes. US patent 3,842,308 describes a gas discharge panel for picture display at least consisting of a base plate, an upper plate of a light-pervious insulating material and a perforated intermediate plate. The intermediate plate is a metal article the surface of which is covered with an adherent oxide by oxidation. The base plate and/or the upper plate comprise a number of strip-shaped mutually insulated electrodes. A part of the surface of these electrodes communicates with a number of cavities formed by the holes of the intermediate plate. These holes define the (main) discharge path. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an inexpensive gas discharging type display panel having high accuracy and a good yield, and having sufficient discharging space, as well as a manufacturing method thereof. For attaining the foregoing object, in the present invention, the auxiliary discharging space and the main discharging space in the cell are separated by a partition wall provided in a partition wall substrate, a metal material of excellent workability is used for the material of the partition wall substrate and formed by providing a covering of insulation material thereon. According to the present invention, the problem of the contrast can be overcome by shielding the light caused by the auxiliary discharging by the partition wall. Further, the problem of the cost for the partition wall substrate can be overcome by using a metal material at a reduced cost and having good workability. This is because the metal material can be formed easily and at a reduced cost into a partition wall substrate of a complex shape, for example, by an etching method, a laser fabrication method, a shaping method and a machining method. However, if a metal material is used for the partition wall substrate, electric charges can not be accumulated upon discharging because of the high conductivity of the metal material, and it may possibly bring about erroneous discharging in other cells. In view of the above, in the present invention, the partition wall substrate is electrically insulated by covering the metal material with an insulation material. It is necessary that the insulation material for covering the exposed portion of the partition wall substrate should be free from defects such as pores. Thus, it is desirable, as the material of the partition wall substrate, to use a metal material capable of forming an oxide film as an insulator, for example, at least one of metals of Al, Ti, Fe, Ta, W, Mo, Cu, Mg, Ni, Co, and Cr or an alloy containing the metal. The method of forming the insulation film on the metal surface can include a method of forming an insulation oxide film by oxidizing the metal itself, or a method of coating the surface of a metal or the surface of an oxide film thereof with a gel obtained by hydrolysis of an organic metal compound (particularly, organic metal oxide or organic metal alkoxide), or an aqueous solution of an alkali silicate and then applying a heat treatment to form an inorganic oxide film. A partition wall substrate of excellent insulation property can be obtained by forming the insulation film by these methods. In a case of using the gel or the aqueous solution, the surface of the partition wall substrate is covered by utilization of a dipping method, a spraying method or an electrodeposition method. Since the method of using the gel or the aqueous solution can form a dense insulation film at a low temperature, it is desirable for obtaining a partition wall substrate Of excellent insulation property. In the present invention, a display panel is constituted by forming a display cell by partitioning cells as picture elements from each other by barrier ribs and forming a partition wall for shielding light caused by auxiliary discharging (discharging space separation partition wall) in each of the cells. The partition wall is preferably arranged in parallel with the front substrate and the back substrate. In the display panel according to the present invention, auxiliary discharging is generated by applying a voltage to the auxiliary discharging electrode disposed on the back electrode, in which charged particles or excited atoms formed by the auxiliary discharging intrude through a conduction path to the main discharging space to facilitate discharging in the main discharging space. That is, in the present invention, the starting voltage for the main discharging is lowered and stabilized by supplying charged particles or excited atoms having an effect of a pilot flame by way of the conduction path to the main discharging space. When an AC voltage is applied between two parallel electrodes formed on the front substrate in a state where the charged particles or excited atoms are supplied in the main discharging space, discharging is formed in the main discharging space and ultraviolet rays are generated causing the fluorescent body to emit light. Display is conducted by observation of the light emission from the fluorescent body through the front substrate. In the present invention, the auxiliary discharging space and the main discharging space are separated and the fluorescent layer is not formed in the auxiliary discharging space. Accordingly, since light is not emitted by the fluorescent light in the auxiliary discharging and the light of gas discharge caused by the auxiliary discharging is shielded by the partition wall, only the light emission caused by the main discharging is observed from the outside of the front substrate. Accordingly, in the present invention, a sufficient contract can be obtained for the displayed images. In addition, in the present invention, since the main discharging takes place between adjacent electrodes provided on the front substrate, the driving voltage can be lowered by making the electrode distance narrower. Lowering of the driving voltage not only can save the consumption power, but also can reduce damage to the protective film due to sputtering caused by discharging and, accordingly, also provides an effect of increasing the working life of the display panel. For maintaining the discharge starting voltage low and stabilizing discharging, it is effective to cover the electrode with a dielectric material to provide a memory function and, further, to cover the insulator with a material such as MgO, CaO, or SrO to enhance the performance of emitting secondary electrons to the discharging space. Further, in order to protect the electric layer, it is preferred to form a protective film such as an MgO film, a CaO film, or an SrO film on the surface of the front substrate and the back substrate facing the discharging space. This is because the protective film suffers from less damages by the sputtering accompanying discharging because of low sputtering rate, and thereby is capable of increasing the working life of the display panel. For the protective film on the side of the front substrate, a transparent material such as an MgO film is preferably used. In the present invention, at least a portion of the barrier rib for defining each of the cells is fabricated as one part, that is, as a partition substrate and a display panel is manufactured by assembling the partition wall substrate, the front substrate and the back substrate. With such a constitution, since it is not required to repeat printing a plurality of times by a thick film printing method or the like for the formation of a thick ceramic film for the partition wall and the barrier rib, the positional accuracy is improved and the production yield is also improved. The partition wall substrate preferably comprises barrier ribs on the side of the front substrate, a discharging space separation partition wall, and barrier ribs for the back substrate, but it may comprise only a portion thereof, for example, barrier ribs on the side of the front substrate and discharging space separation partition walls. Further, in the present invention, the fluorescent layer is preferably formed on the lateral surface of the barrier ribs on the side of the front substrate constituting the inner wall of the main discharging space and on the surface of the front substrate of the discharging space separation partition wall. With such a constitution, since the area of the fluorescent layer can be increased, the light emission efficiency caused by discharging can be improved. If the light emitted from the fluorescent body permeates the barrier ribs between each of the cells and partition walls in parallel therewith formed between the front substrate and the back substrate and leaks to adjacent cells, undesirable color mixing is caused in the case of the color display panel. Since the barrier rib and the discharging space separation partition wall used in the gas discharging type display panel according to the present invention comprises a metal material covered with an insulator, it is not transparent and hinders the light emitted by electric discharging from leaking into adjacent cells, so that it has an effect of preventing color mixing. Further, if the insulator is transparent, since the light emitted by the discharge is reflected on the surface of the metal material for the partition substrate, an effect of improving the emission efficiency can also be obtained. Further, if the partition wall and the barrier rib are formed with metal, they are less subject to breaking as compared with those formed by glass or ceramic, and the thickness of the partition wall and the barrier rib can be reduced. Further, since the fabricability is excellent, the height of the barrier rib on the side of the front substrate can be increased easily. Therefore, in accordance with the present invention, since the discharging space is increased, the coating amount of the fluorescent body can be increased to improve the luminosity. Further, since the supply of the charged particles and the like from the auxiliary discharging space to the main discharging space is facilitated, the address voltage can be lowered. Further, since the cell pitch can be narrowed, a panel with high accuracy can be manufactured. For the metal material used for manufacturing the partition wall substrate in the present invention, any material may be used so long as it gives no undesired effect on vacuum discharging. It is preferred to use a material having satisfactory machinability, etching property, laser fabricability or moldability. Since the machining method is applied by using a drill or a bit, it is difficult to fabricate glass or ceramic by this method. However, the metal material can be fabricated relatively simply by this method. According to this method, since the fabrication size can be controlled by the size of the tool, the conduction path or the like can be fabricated simply in an identical shape. In the etching method, patterning is applied by using a photo-process. Since dimensional accuracy for exposure and development is high in this method, fabrication with high accuracy is possible. While the laser fabrication method undergoes the effect, for example, of moving accuracy of a table on which a work is placed, distribution of energy of the laser beam or the like, fabrication is possible at an accuracy comparable with that of the etching method. In the shaping method, the substrate is shaped by shaping the substrate under pressure in a mold, which is excellent for mass productivity. In a case of fabrication into a structure having repeating cells of an identical size as in the partition wall substrate of the present invention, a shaping method of excellent mass productivity is particularly suitable. The shaping method includes a press fabrication method and a roll fabrication method. In the press fabrication method, shaping is conducted by putting the substrate between upper and lower molds and applying a pressure. Heat may be applied sometimes for improving the moldability. In the roll fabrication method, shaping is applied by passing a substrate between upper and lower rolls formed with a shape. The shaping product shaped into the form of the partition wall and the barrier rib by the method as described above is coated with an insulator for insuring the insulation property. For the coating with the insulator, a layer of an insulation material such as glass may be formed on the surface. However, a method of covering the metal material by heating in air or the like thereby forming an insulation oxide film is a convenient and inexpensive method and hence is excellent. In view of the above, for a substrate for forming the shaping product, it is desirable to use a metal material capable of forming an oxide film as an insulator densely and it is desirable to use at least one of the metals, for example, of Al, Ti, Fe, Ta, W, Mo, Cu, Mg, Ni, Co and Cr, or an alloy containing the metal. While the insulation property can be ensured only with the oxide film described above, it is desirable to further form an insulation film with an insulation material on the oxide film. The insulation film by the insulation material may be formed on the surface of the fluorescent body so long as the film allows ultraviolet rays or a light at a predetermined wavelength (display color) to permeate therethrough. In such a constitution, since it also acts as the protective film for a fluorescent body, the working life of the fluorescent body can be increased. In a case of forming the insulation film on the surface of the fluorescent layer, it may be formed only on the surface of the fluorescent layer or may be formed entirely or partially of the surface of the partition wall substrate containing the fluorescent layer. The insulation layer formed on the surface of the metal shaping product, the surface of the metal oxide layer or the surface of the fluorescent layer of the partition wall substrate is preferably an inorganic oxide, for example, glass which is particularly preferably transparent. The inorganic oxide can include an inorganic oxide obtained by heating a gel formed by hydrolysis, for example, of an organic metal compound (hereinafter referred to as an organic metal gel) or an aqueous solution of an alkali silicate (hereinafter referred to as water glass). The organic metal gel comprises ceramics dispersed at a molecular level and an inorganic material can be obtained by removing a solvent such as water or alcohol. However, it is desirable to apply a sufficient heat treatment in order to thoroughly remove adsorbed water or alcohol so that gas is not generated during discharging and to obtain an insulator layer which is homogeneous and strong. However, since the gel comprises ceramics at the molecular level, the sintering temperature is low and can be heat-treated sufficiently at a temperature lower than 450°C which is a strain point for soda glass material. For obtaining a homogeneous and strong insulator layer, it is desirable to apply heat treatment at least at 50°C or higher. If the temperature for the heat treatment is low, although a solvent such as water or alcohol can be removed, hydroxy groups, etc. adsorbed on the surface of the insulator formed can not sometimes be eliminated completely, so that steams or alcohols may sometimes be released when the panel is evacuated after assembling and, further, introduced with gas after sealing, which may possibly give an effect on discharging. In addition, if the temperature for the heat treatment approaches 450°C as the strain point of the soda glass material, glass is liable to be deformed though the strain point is not exceeded. Moreover, since a glass plate of a large area used for a gas discharging type display panel is particularly liable to be deformed even by its own weight, it is required not to elevate temperature as much as possible. Then, the temperature of the heat treatment for the organic metal gel in the present invention is desirably higher than 100°C and lower than 400°C. The organic metal gel used in the present invention is obtained, for example, by hydrolyzing a solution of an organic metal compound such as of Si, Ti, Al or Zr (aqueous solution or alcohol solution) at or near the normal temperature. A polycondensating reaction proceeds in the reaction solution along with proceeding of hydrolysis to form a sol and, when the reaction proceeds further, a gel used in the present invention is obtained. The example of the organic metal compound used herein can include a metal alkoxide represented by the general formula M(OR1)n. In this case, M represents a metal atom (including semi metal) including, for example, Si, Ti, Al and Zr. R1 represents an organic group for which an alkyl group of 1 to 5 carbon atoms is preferred. A symbol n is a positive integer defined by the valency of M and is usually from 1 to 4. The metal alkoxide or hydrolysis product thereof is changed into a metal oxide by a heat treatment. The metal alkoxide usable in the present invention can include, for example, tetra(n-butyl) silicate: Si(OC4H9)4, tri(sec-butoxyl) aluminum: Al(OC4H9)3, tetra(n-propyl) titanate; Ti(OC3H7)4, tetra(n-butyl) zirconate: Zr(OC4H9)4 and trimethyl borate: B(OCH3)3. The metal alkoxide can be obtained easily with high purity, for example, by using a metal chloride as the raw material for synthesis and purifying the chloride by a usual purification method such as distillation and recrystallization. Further, the metal alkoxide can be prepared for almost of metals and they are usually liquid at a normal temperature. Then, raw material gel for the glass or ceramic having a desired composition can be prepared easily by mixing a plurality kinds of the metal alkoxide and hydrolyzing them. Table 1 shows examples of the compositions for the insulators capable of being obtained from the organic metal gels. No. SiO 2 Al 2 O 3 TiO 2 ZrO 2 B2O 3 1 100 2 37 63 3 42.9 57.1 4 54 46 5 39.6 33.7 26.7 6 38.5 32.8 28.7 7 32.6 29.4 17.1 18.4 2.5 8 32.8 67.2 9 22.7 77.3 10 23.6 40.1 36.3 11 84 13 12 22.1 37.7 40.2 Further, water glass as one of the insulation materials provided in accordance with the present invention is a concentrated aqueous solution of an alkali silicate represented by R220, nSiO2 (the amount of water is 70 to 90% by weight based on the entire amount). In this case, R2 is at least one of sodium, potassium, lithium and rubidium, with potassium being particularly preferred. Further, n is 4 - 6, and the polymerization degree of the resultant glass is insufficient liable to absorb moisture if n is less than 4, whereas the hydrolyzing rate is slow if n is greater than 6. Compositional examples of the insulation materials obtained from water glass are shown in Table 2. No. SiO 2 K 2 O Li 2 O Na 2 O Rb 2 O 1 79.28 20.72 2 76.13 23.87 3 71.84 28.16 4 92.35 7.65 5 90.95 9.05 6 85.33 14.67 7 82.95 17.05 8 65.86 34.14 9 61.66 38.34 10 81.09 12.71 2.02 4.18 11 82.19 10.74 7.07 12 79.38 12.44 8.18 For forming the insulation layer, in addition to the method of using the organic metal gel or water glass as described above, a sputtering method, a chemical gas phase reaction method or a thick film printing method, etc. can also be used. BRIEF DESCRIPTION OF THE DRAWINGS Figs. 1(a)-1(c) show cross sectional views illustrating a structure of a gas discharging type color display panel of Example 1. Figs. 2(a)-2(c) show cross sectional views illustrating a structure of a gas discharging type color display panel of Example 2. Figs. 3(a)-3(c) show cross sectional views of a display panel manufactured in Example 3. Fig. 4 shows a perspective view illustrating a structure of a gas discharging type color display panel of the prior art. Figs. 5(a)-5(c) show cross sectional views of the structure of a gas discharging type color display panel of the prior art. Fig. 6 is an enlarged cross sectional view illustrating the structure of a barrier rib in a gas discharging type color display panel of the prior art. Figs. 7(a) and 7(b) show cross sectional views illustrating the structure of a barrier rib in a gas discharging type color display panel of Example 1. Figs. 8(a)-8(p) are explanatory views illustrating steps for manufacturing a gas discharging type color display panel of Example 1. Figs. 9(a) and 9(b) are enlarged cross sectional views illustrating the structure of a barrier rib in a gas discharging type color display panel of Example 2. Figs. 10(a) and 10(b) shows a cross sectional view illustrating the structure of a barrier rib in a gas discharging type color display panel of Example 3. Fig. 11 shows a display system utilizing the gas discharge display panel of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of gas discharging type color display panels according to the present invention will be explained specifically referring to the drawings. Materials, thickness, temperature, time and apparatus used referred to in the subsequent explanation show only one mode of practice and the present invention is not restricted to the examples. <Example 1> Figs. 1(a)-1(c) and Figs. 7(a) and 7(b) show cross sections of a gas discharging type color display panel manufactured by this example. The gas discharging type color display panel of this embodiment, as shown in Fig. 1(a)-(c), comprises a front substrate 1, a back substrate 2, and a partition wall substrate 3 for partitioning a gap therebetween to form cells as picture elements. A gas mixture of He and Xe (Xe content: 5 vol%) is sealed in a gap between the front substrate 1 and the back substrate 2. The front substrate 1 has a soda glass plate 4a, ITO electrodes 5a, 5b formed on the surface thereof and extended in a direction perpendicular to the plane of Fig. 1, buss electrodes 6a, 6b formed on the surface of the ITO electrodes 5a, 5b, a dielectric layer 7a formed on the surface of the soda glass plate 4a so as to cover the ITO electrodes 5a, 5b and the buss electrodes 6a, 6b and, further, a MgO film 8a formed on the surface of the dielectric layer 7a. The electrode pattern formed with the ITO electrodes 5a, 5b and the buss electrodes 6a, 6b is patterned as a plurality of parallel linear patterns such that two parallel electrodes are disposed for each of the cells of cell rows arranged in one direction, among the cells arranged in a matrix. In the two main discharging electrodes on every cell row, the main discharging electrodes 5a and 6a are disposed on a conduction path at the center of the cell row, while the main discharging electrodes 5b, 6b are disposed across two cell rows, as shown in Fig. 1(a). The ITO electrodes 5a, 5b are transparent electrodes. However, the ITO electrodes 5a, 5b have high wiring resistance value and if only one of the electrodes is used, the driving speed for the main discharging is slow. In the display panel of this embodiment, the buss electrodes 6a, 6b made of metal and extending in parallel with linear lines formed by the ITO electrodes 5a, 5b are disposed to lower the wiring resistance value of the electrodes on the front substrate 1. However, since the buss electrodes 6a, 6b are not transparent, the width is desirably as narrow as possible. This is for reducing the amount of light emitted from the fluorescent body 14 and shielded by the buss electrodes 6a, 6b. The back substrate 2 comprises a soda glass plate 4b, address electrode 9 formed on the surface thereof, the dielectric layer 7b formed on the surface of the first address electrode 9 and an MgO film 8b formed so as to cover the surface of the dielectric layer 7b. The address electrode 9 is patterned as a plurality of parallel linear patterns such that three electrodes extend in parallel with each two rows of cells in the cell row and orthogonal to the extending direction of the ITO electrodes 5a, 5b. One of the three address electrodes 9 at the center is disposed across two cell rows, as shown in Figs. 1(b) and 1(c). Since the MgO films 8a, 8b formed on the front substrate 1 and the back substrate 2 have low sputtering rate and excellent sputtering resistance, they can suppress damage by sputtering caused by discharging and act as protection films for the dielectric layers 7a, 7b. The MgO films 8a, 8b are effective for preventing discharge sputtering and making the working life of the display panel longer. Further, since the MgO films 8a, 8b are transparent, they easily permeate the light emitted from the fluorescent body 14 and are suitable to use for the display panel. Fig. 1(a) is a cross sectional view showing the display panel cut along a plane in parallel with the address electrode 9 and vertical to the surface of the substrates 1, 2. Further, Fig. 1(b) is a cross sectional view at a position A in Fig. 1(a) and the cutting plane is vertical to the address electrode 9 and vertical to the surface of the substrates 1, 2. Fig. 1(c) is a cross sectional view at a position B in Fig. 1(a) and the cutting plane is vertical to the address electrode 9 and vertical to the surface of the substrates 1, 2. The partition wall substrate 3 comprises barrier ribs 11, 12 in contact with the MgO film 8a of the front substrate 1 and the MgO film 8b of the back substrate 2, a partition wall 13 in parallel with the front substrate and the back substrate, and a fluorescent layer 14 formed on the lateral side of the barrier rib 11 on the side of the front substrate and the surface of the partition wall 13 on the side of the front substrate. The barrier ribs 11, 12 and the partition wall 13 are shaped integrally and comprise metal shaping members 11a, 12a, 13a covered with insulation layers 11b, 12b, 13b. The fluorescent layer 14 is a coating film comprising a fluorescent body emitting green, blue or red light by radiation rays and, since the fluorescent layer 14 is provided for a wide range in this embodiment, the light emitting efficiency by the main discharging is good. A fluorescent body to be used that emits a specified color is determined on every cell such that the arrangement of color for the entire substrate forms a predetermined pattern. The barrier ribs 11, 12 are in a lattice form for partitioning the gap between the substrates 1, 2 to form cells. Fig. 7(a) shows a cross sectional view of the barrier rib 11 on the side of the front substrate cut along a plane parallel with the surface and the rear face of the front substrate, while Fig. 7(b) shows a cross sectional view of the barrier rib 12 on the side of the back substrate cut along a plane in parallel with the surface and the rear face of the front substrate. A cell formed with the front substrate 1, the back substrate 2 and the partition wall substrate 3 is separated by barrier ribs 11, 12 from adjacent cells. In this embodiment, the partition wall 13 is disposed horizontally to the glass plates 4a, 4b, but it is not necessary to be horizontal so long as it does not hinder the movement of charged particles, etc. For the space in the cell, the space 3c between the partition wall 13 and the back substrate 2 is defined as a space for auxiliary discharging, while the space 3d between the partition wall 13 and the front substrate 1 is defined as a space for main discharging. The space 3c for the auxiliary discharging and the space 3d for the main discharging are in communication by the conductive path 3e formed between the end of the partition wall 13 and the barrier rib. In the cell, a discharge gas is sealed as described previously. In the gas discharging type color display panel of this embodiment, when an AC voltage is applied between two adjacent address electrodes 9a, 9b disposed to the back substrate 2, auxiliary discharging occurs in the auxiliary space 3c of the cell present above them by way of the dielectric layer 7b. In the display panel of this embodiment, a voltage is applied to all of the main discharging electrodes 5b and 6b across two rows of the display cells. Then, when an AC voltage is applied to the main discharging electrodes 5a, 6a used exclusively for the cell to be displayed in a state where the auxiliary discharging is generated as described above, a charge pattern of the electrodes is introduced by way of the dielectric layer 7a to the surface of the MgO layer 8a and, since the effect of the auxiliary discharging prevails by way of the conductive path 3e to the main discharging space 3d, main discharging is caused between different charges on the surface of the MgO layer 8a. That is, the main discharging is caused between charges introduced by way of the dielectric layer 7a to the surface of the MgO layer 8a by the application of a voltage to the ITO electrode 5a disposed with the bus electrode 6a and charges introduced by way of the dielectric layer 7a to the surface of the MgO layer 8a by the application of a voltage to the ITO electrode 5b disposed with the buss electrode 6b. The main discharging does not occur in a cell in which a voltage is not applied to the non-common main discharging electrodes 5a, 5b or the cell in which auxiliary discharging is not generated. This main discharging excites the gas in the discharging space (gas mixture of He and Xe), to generate radiation rays (ultraviolet rays), and the radiation rays excite the fluorescent body 14 to emit visible light. Images are formed on the display panel by selecting an electrode to which the voltage is applied, thereby generating the visible light in each of desired cells and emitting the visible light through the front substrate 1 to the outside. As described above, in this embodiment, each of the cells is partitioned by the barrier rib 3a, and the space between the front substrate 1 and the back substrate 2 is partitioned by the partition wall 13, by which the auxiliary discharging is concealed from the fluorescent body 14 so that the radiation rays generated by the auxiliary discharging not hit on the fluorescent body 14. Therefore, in the display panel of this embodiment, even when the auxiliary discharging is generated by the addresses electrode 9 on the side of the back substrate 2, the light emitted by the auxiliary discharging is hindered by the partition wall 13, and the fluorescent body 14 is caused to emit light only by the main discharging, accordingly, the fluorescent body 14 does not emit light in the cell in which only the auxiliary discharging occurs but the main discharging does not occur (that is, a cell in which the voltage is applied to the address electrode 9 but the voltage is not applied to the buss electrodes 6a, 6b), and only the light emitted by the main discharging can be observed from the front substrate 1, so that sufficient contrast can be obtained. A method of manufacturing a gas discharging type display panel of this embodiment is explained with reference to Figs. 8(a)-8(p). A: Manufacture of Front Substrate (1) Formation of Main Discharging Electrode At first, a front substrate 1 is manufactured. A soda glass plate 4a of about 85 cm width, about 70 cm dense and about 2.8 mm thickness having ITO film 5c formed on one of the surface or rear face (Fig. 8(a)) is provided. A light sensitive resin composition is coated on the surface of the ITO film 5c in a dust proof chamber at a room temperature of 15 to 25°C, and a humidity of 60%, the coating film of the light sensitive resin composition being exposed to an exposure amount of 300 - 250 mJ/cm2 by way of a mask having a predetermined pattern by a super-high pressure mercury lamp at 3kW (S kW power), spray-developed by using an aqueous 0.2 - 0.5% solution of sodium carbonate under the condition at a developing temperature of 25°C and at a pressure of 1.2 kg/cm2 for 105 sec, then neutralized with 0.1% diluted acid, washed with water and dried to form a resist film of a predetermined pattern. Then, after etching the exposed portion of the ITO film 5c by the etching solution, the resist film is peeled off with a peeling liquid. Thus, the ITO film 5c is patterned and ITO electrodes 5a, 5b are formed at a predetermined position (Fig. 8(b)). In the same manner, after forming a resist film of a predetermined pattern on the resultant ITO electrodes 5a, 5b, buss electrodes 6a, 6b each of 0.05 mm width and 0.03 mm thickness are formed by an electroless plating method (Fig. 8(c)). Any metal having good conductivity may be used for the electrode material and copper is used in this embodiment. After the plating treatment, the resist film is peeled off by the peeling solution. (2) Formation of Dielectric Layer A hydrolysis type coating agent comprising Al, si, O as the main ingredient (composition No. 11 in Table 1). In this embodiment, a gel obtained by hydrolysis at a normal temperature of an n-butanol solution containing tri(n-butoxyl) aluminum, tetra(n-butyl) silicate and tri(n-butoxyl) borane at a ratio of 84 : 13 : 3 (weight ratio) each being converted as a metal oxide) is coated by a blade method to the surface of the ITO electrodes 5a, 5b, bus electrodes 6a, 6b and the glass plate 4a, and heated at 50 - 500°C for 5 to 60 min, to form a transparent dielectric layer 7a of 0.003 - 0.01 mm thickness (Fig. 8(d)). When the gas discharged in vacuum is analyzed for the product heated at 50 - 80°C for 60 min, water or gas of alcohol is detected. Further, in the product heated at 420 - 500°C for 10 min, warp is caused at about 0.15 mm to the soda glass plate 4a. The product heated at a temperature from 100 to 400°C for 5 to 60 min is satisfactory releasing no gases in vacuum and causing no warp to the soda glass plate 4a. Then, in the subsequent step, a product heated at a temperature 100 to 400°C for 5 to 60 min is used. (3) Formation or Protective Film A hydrolysis coating agent comprising MgO and O as the main ingredient (gel obtained by hydrolysis at a normal temperature of n-butanol solution containing di(n-butoxyl) magnesium) is spin-coated on the surface of the resultant dielectric layer 7a, and heated at a low temperature in the same manner as in (2) above at a temperature from 100 to 400°C for 5 min to 60 min to form an MgO film 8a having 0.001 to 0.005 mm thickness (Fig. 8(e)). The dielectric layer 7a and the protective film 8a can be formed in the same manner by a spray method, a roll method, dipping method, a printing method or the like in addition to the method described above. With the steps (1) - (3) described above, the front substrate 1 is obtained without heating to a temperature higher than the strain point (450°C) of the soda glass plate 4a. In the steps described above, there is no dimensional change in the soda glass 4a. B. Manufacture of Back Substrate (4) Formation of Auxiliary Discharging Electrode A method of manufacturing a back substrate 2 is explained. At first, a light sensitive resin composition is coated on a back substrate comprising soda glass plate 4b cleaned by using, for example, a neutral detergent (about 85 cm width, about 70 cm length, about 2.8 mm thickness) shown in Fig. 8(f), and the coating film of the light sensitive resin composition is exposed by way of a mask having a predetermined pattern by a super-high pressure mercury lamp at 3 kW (8 kW power) by an exposure amount of 200 to 250 mJ/cm2, spray-developed by using an aqueous 0.2 - 0.5% solution of sodium carbonate under the conditions at a developing temperature of 25°C and at a pressure of 1.2 kg/cm2 for 105 sec, then neutralized with 1% diluted acid, washed with water and then dried to form a resist film of a predetermined pattern. Thus, a resist film having a predetermined pattern is formed. An address electrode 9 (9a, 9b) comprising copper having 0.1 mm width, and 0.003 mm thickness is formed by an electroless plating method to a portion of the glass plate 4b not covered with the resist film. After the plating treatment, the resist film is peeled off by a peeling solution (Fig. 8(g)). The pattern dimension and the thickness of the auxiliary discharging electrode may be determined based on the resistance value required for the auxiliary discharging electrode. (5) Formation of Dielectric Layer and a Protective Layer The same hydrolysis type coating agent as used in the step (2) described above is coated by a blade method or a spray method to the surface of the glass substrate 4b so as to cover the resultant auxiliary discharging electrode 9, and heated at a temperature of 100 to 400°C for 1 to 60 min to form a dielectric layer 7b of 0.001 to 0.03 mm thickness (Fig. 8(h)). Further, a protective layer 8b comprising MgO is formed in the same manner as in the step (3) described above (Fig. 8(i)). The back substrate 2 is thus obtained. A chip pipe (not illustrated) is attached to the back substrate 2 for evacuation and gas introduction conducted after assembling the panel. C. Manufacture of Partition Wall substrate (6) Formation of Conduction path A partition wall substrate 3 is manufactured as follows. At first, a light sensitive resin composition is coated on a metal aluminum plate 3a of about 85 cm width, about 65 cm length and about 0.5 mm thickness, the coating film of the light sensitive resin composition is exposed by way of a mask having a predetermined pattern by a super-high pressure mercury lamp at 3 kW (8 kW power) at an exposure amount of 200 to 250 mJ/cm2, spray-developed by using an aqueous 2 - 0.5% solution of sodium carbonate under the conditions at a developing temperature of 25°C and at a pressure of 1.2 kg/cm2 for 105 sec, then neutralized with 0.1% diluted acid, washed with water and dried, to form a resist film of a predetermined pattern. A resist film 31 of a predetermined pattern is thus formed (Fig. 8(j)). Next, a portion of the aluminum plate 3a not covered with the resist film 31 is etched, a through hole having a size at an opening portion of 0.1 mm x 0.15 mm is formed as a conduction path 3e and then the resist film is peeled off by a peeling solution (Fig. 8(h)). (7) Formation of Barrier Rib and Partition Wall A light sensitive resin composition is coated again to both of the surface and the rear face of the metal aluminum plate 3a with a resist film 32 of a predetermined pattern being formed in the same manner as described above, and a portion not covered with the resist film 32 is removed to a predetermined depth by a both face etching method to form a recess constituting a main discharging space and an auxiliary discharging space. Thus, a molding product having barrier ribs 11 on the side of the substrate 1, the barrier ribs 12 on the side of the back substrate 2 and a partition wall 13 for separating the main discharging space and the auxiliary discharging space formed integrally is obtained (Fig. 8(m)). (8) Formation of Insulation Film The same hydrolysis type coating agent as used in step (2) is coated on the surface of the resultant molding product by a dipping method, and heated at a low temperature in the same manner as for the formation of the dielectric layer 7a at a temperature from 100 to 450°C for 5 to 60 min to form insulation material 81 of 0.005 to 0.015 mm thickness. Thus, the insulation layer 13a for the partition wall 13 and the insulation layers 11a, 12a for the barriers 11, 12 are formed (Fig. 8(n)). (9) Formation of Fluorescent Layer Further, after spraying each of fluorescent bodies for green, blue and red from the side of the front substrate 1 by way of masks having predetermined patterns for green, blue and red, respectively, to the side of the front substrate of the part, they are dried at a temperature of 150°C to 300°C for 5 min to 60 min to form fluorescent layer 14 (Fig. 8(o)). If color display is not required, it may suffice to form a fluorescent layer of an identical color for the entire cell. With the steps (6) - (9) described above, a partition wall substrate 3 as a part having the barrier rib 3a, partition wall 13 and the fluorescent layer 14 is obtained. D. Assembling (10) Assembling of Substrates 1 - 3 After aligning the substrates 1 - 3 obtained as described above and covering the periphery thereof by coating a sealing material (flit glass) by a dispenser, a heat treatment is applied at 300°C to 400°C to fix the sealing material 33. The display panel us assembled at a good accuracy with no distortion for the substrates 1 - 3 (Fig. 8(p)). (11) Injection of Gas Finally, the inside of the cell is evacuated by drawing air by way of a chip pipe (not illustrated) and a gas mixture comprising He-5% Xe is introduced till the gas pressure at the inside of the cell reached 300 Torr to 500 Torr (39.9 kPa - 66.5 kPa) and then the chip pipe is heated to chip-off by local heating to obtain a gas discharging type color display panel having the same constitution as that shown in Figs. 1(a)-1(c). E. Result With the steps (1) - (11) described above, a gas discharging type color display panel is manufactured at a reduced cost and with high accuracy, in which the gap between the front substrate 1 and the back substrate 2 is divided by the barrier rib 3a to form a plurality of cells, the inside for each of the cells is separated into the main discharging space 3d and the auxiliary discharging space 3c by the partition wall 13 for concealing the auxiliary discharging, and the main discharging space 3d is in communication with the auxiliary discharging space 3c by way of the conduction path 3e. In the display panel of this embodiment, the thickness of the partition wall 13 is 0.1 mm, and the conduction path 3e is disposed at the center of the partition wall 13 in each of the cells. Further, the main discharging space 3d has a size of 0.33 mm length, 1.1 mm width and 0.3 mm height in Fig. 1(a), while the auxiliary discharging space 3c has a size of 0.33 mm length and 0.1 mm height in Fig. 1(a). In the display panel of this embodiment, since light emission by the auxiliary discharging is shielded by the partition wall 13 and only the emission by the main discharging is observed, a sufficient contrast (more than 400 : 1) can be obtained between the cell causing main discharging and a cell not causing main discharging. <Example 2> While the barrier rib 11 on the side of the front substrate and the barrier rib 12 on the side of the back substrate were collectively formed by the both-face etching method in Example 1, the barrier rib 12 on the side of the back substrate is formed on the protective film 8b of the back substrate 2 in this embodiment. The method of manufacturing the display panel in this embodiment is identical with that in Example 1 except that the method of forming the barrier rib 12 is different. Then, only the steps different from Example 1 are explained here while saving explanation for the remaining steps. The cross sectional views of the display panel manufactured in this embodiment is shown in Figs. 2(a)-(c). Like that in Fig. 1(a), Fig. 2(a) is a cross sectional view for a portion of a display panel in this embodiment cut along a plane parallel with the address electrode 9 and vertical to the surface of the substrates 1, 2. Further, Fig. 2(b) is a cross sectional view at position A in Fig. 2(a) and the cutting plane is vertical to the address electrode 9 and vertical to the surface of the substrates 1, 2. Fig. 2(c) is a cross sectional view at a position B in Fig. 2(a) and the cutting plane is vertical to the address electrode 9 and vertical to the surface of the substrate 1, 2. Fig. 9(a) and (b) show cross sections cutting along a plane parallel with the main surface of the front substrate 1 (a surface exposed to the outside in each of the surface and the rear face). The size of the discharging space of the display panel manufactured by this embodiment is identical with that in Example 1. A. Manufacture of Back Substrate A hydrolysis type coating agent used in the step (2) of Example 1, mixed with a spherical alumina particle and potassium titanate fiber as a binder (mixing ratio of the binder: 80 wt%) is coated at a predetermined position on the protective film 8b of the back substrate 2 manufactured in the same manner as in steps (4) and (5) of Example 1 by a blade method or a printing method and heated in the same manner as in the step (2), to form a barrier rib 12 of 0.1 to 0.2 mm thickness. B. Manufacture of Partition Wall Substrate Partition wall substrate 3 is manufactured in the same manner as in Example 1 using a metal aluminum plate 3a of about 85 cm width, about 65 cm length and 0.4 mm thickness in this embodiment as a substrate 3a to be etched. However, the surface of the aluminum plate 3a on the side of the back substrate is covered with a resist film 32 and only the surface on the side of the front substrate is etched. C. Result Finally, when the front substrate 1, the partition wall substrate 3 not formed with the barrier rib 12 on the side of the back substrate 12, and the back substrate 2 formed with the barrier rib 12 on the side of the back substrate manufactured in the same manner as in Example 1 are aligned and laminated in this order, the periphery is sealed in the same manner as in Examplc 1, Re-5% Xe gas is sealed, and then the chip pipe is chipped off to obtain a gas discharging type color display panel, a display panel of good contrast for color emission is obtained like that in Example 1. <Example 3> In this example, a display panel is manufactured in the same manner as in Example 2 except for forming the barrier rib on the side of the front substrate with ceramics. The method of manufacturing the display panel in this embodiment is identical with that in Example 2 except that the method of forming the barrier rib 11 is different. Then, only the steps different from Example 2 are explained here while saving explanation for the remaining steps. Figs. 3(a)-3(c) show cross sectional views of a display panel manufactured in this embodiment. Like that in Fig. 1(a), Fig. 3(a) is a cross sectional view when a portion of a display panel of this embodiment is cut along a plane parallel with the address electrode 9 and vertical to the surface of substrates 1, 2. Further, Fig. 3(b) is a cross sectional view at a position A in Fig. 3(a) and a cutting plane thereof is vertical to the address electrode 9 and vertical to the surface of the substrates 1, 2. Fig. 3(c) is a cross sectional view at a position B in Fig. 3(a) and a cutting plane thereof is vertical to the address electrode 9 and vertical to the surface of the substrates 1, 2. Figs. 10(a) and 10(b) shows a cross section of the barrier ribs 11 and 12 cut along a plane in parallel with the main surface of the front substrate 1. The size of the discharging space in the display panel manufactured in this embodiment is identical with that in Example 1. In this example, a partition wall substrate 3 is manufactured in the same manner as in Example 1 by using a metal aluminum plate 3a of about 85 cm width, about 65 cm length and 0.2 mm thickness as the substrate material 3a for the partition wall substrate 3. However, after manufacturing the conduction path in step (6), the step (7) is not conducted and the molding product is covered with the insulation film like that in step (8), a hydrolysis type coating agent used in the step (2) of Example 1 mixed with a spherical aluminum particle and potassium titanate fiber as a binder (binder mixing ratio : 80 wt%) is coated at a predetermined position on the surface of the insulation film, and heated in the same manner as in step (2), to form a barrier rib 11 of 0.15 to 0.25 mm thickness. Finally, when the front substrate 1, the partition or side wall substrate 3 not formed with the barrier rib 11 on the side of the front substrate and the barrier rib 12 on the side of the back substrate, and the back substrate 2 having the barrier rib 12 on the side of the back substrate manufactured in the same manner as in Example 2 are aligned and stacked in this order, the periphery is sealed in the same manner as in Example 1, He-5% Xe gas is sealed, and the chip pipe is chipped off to obtain a gas discharging type color display panel, a display panel of good contrast for color emission is obtained in the manner as in Example 1. <Example 4> While the aluminum plate is used as the base material 3a for the partition wall substrate 3 in the Examples 1 to 3 described previously, the display panel is manufactured in this embodiment by using nickel, covar, stainless steel, 426 alloy, copper, magnesium, iron, cobalt, chromium, titanium, tantalum, tungsten or molybdenum, in the same manner as in Examples 1 to 3, whereby the same effects as those in Example 1 is obtained. <Example 5> When a display panel is manufactured in the same manner as in Examples 1 to 3 except for applying fabrication by a laser fabrication method, a shaping method or a machining method instead of the etching method in the steps (6) and (7), same effects as those in Examples 1 to 3 can be obtained. <Example 6> While the insulation layer 81 is formed in Examples 1 to 3 by using the gels of the composition of No. 11 in Table 1 as the hydrolysis type coating agent in Examples 1 to 3, a display panel is manufactured in the same manner as in Examples 1 to 3 by using the coating agent of the composition shown by No. 1-10 or 12 in this embodiment, whereby the same effects as those in Examples 1 to 3 is obtained. <Example 7> While the insulation layer 81 is formed in Examples 1 to 3 by using the gel of the composition No. 11 in Table 1 as the hydrolysis type coating agent, a display panel is manufactured in the same manner as in Examples 1 to 3 by using a water glass of the composition of No. 1 to 11 or 12 in Table 2, as the coating agent, in this embodiment, whereby the same effects as those in Examples 1 to 3 is obtained. <Example 8> In the formation of the insulation film 81, while the film of the hydrolysis type coating agent is formed by the dipping method in Examples 1 to 3, it is formed by a spray method or an electrodeposition method in this example, whereby the same effects as those in Examples 1 to 3 is obtained. Fig. 11 shows a display system utilizing the gas discharge display panel of the present invention. As shown, address electrodes of the panel 1000 are supplied with signals from address drivers 1100 and other electrodes of the panel are supplied with signals from a scan driver 1200 and pulse generators 1300. The scan driver also being coupled to a level shifter 1400, and the drivers, pulse generators and level shifter being controlled by a control unit 1500 for providing the desired display. The control unit 1500 is coupled to a power control unit 1600 which is coupled to a converter, for example. As has been described above, in the present invention, cells as picture elements are separated from each other by barrier ribs to form discharging cells, and partition walls are formed in each of the cells in parallel with the plane of the front substrate and the back substrate for concealing light by the auxiliary discharging, to constitute a display panel. Therefore, according to the present invention, since auxiliary discharging is generated by two parallel electrodes at the cell position formed on the back substrate, main discharging is generated by applying an AC voltage between two parallel electrodes formed on the front substrate by way of the conduction path and the fluorescent body is caused to emit light by ultraviolet rays generated by the discharging and, when the light permeating the front substrate is observed, since the light emission by the auxiliary discharging is concealed by the partition wall and only the light emission by the main discharging can be observed, a sufficient contrast can be obtained for the displayed images. Further, the driving voltage can also be lowered and, moreover, the working life can be increased. Further, according to the present invention, since the barrier rib between each of the cells and the partition wall disposed parallel with the surface of the front substrate and the back substrate in each of the cells for concealing the auxiliary discharging can be constituted as a partition wall substrate, and they can be constituted so as to be handled as one part, printing for several times by a thick film printing method or the like is not required and improvement for the positional accuracy and improvement for the production yield can be attained. Additionally, according to the method of manufacturing a gas discharging type color display panel of the present invention, the partition wall with high accuracy can be formed at a reduced cost by using a metal material covered with the insulation material for the partition wall substrate and, further, since the emitted light can be reflected on the surface of the metal, a panel at high luminosity can be obtained.

Claims: A gas discharge display panel comprising: a back substrate (2) having at least two auxiliary discharge electrodes (9a, 9b) thereon which are arranged in a manner that if an AC voltage is applied between two adjacent auxiliary discharge electrodes (9a, 9b), auxiliary discharging occurs; a front substrate (1) having at least two main discharge electrodes (5a, 6a, 5b, 6b) thereon which are arranged in a manner that if a voltage is applied to a first one of the main discharge electrodes (5b, 6b) and an AC voltage is applied to a second one of the main discharge electrodes (5a, 6a), and if at the same time auxiliary discharging occurs, then main discharging is caused; and the front substrate (1) is spaced from the back substrate (2) so as to delimit a gap therebetween; and a partition member (13) extending substantially parallel to and between the front and back substrates (1, 2) for forming a main discharge space (3b) on a front substrate side and an auxiliary discharge space (3c) on a back substrate side, the partition member (13) being a metal material member (13a). A gas discharge display panel according to claim 1, wherein the metal member (13a) has an insulator (13b) on at least a portion thereof. A gas discharge display panel according to claim 1, further comprising a barrier rib (11, 12) connected at least at one end to at least one of the front substrate (1) and back substrate (2) for delimiting the gap between the front and back substrates (1, 2), and a fluorescent layer (14), the partition member (13) separating the space defined by the barrier rib (11, 12) into the main discharging space (3d) and the auxiliary space (3c), the partition wall being the metal material member (13a) having an insulator (13b) on at least a portion thereof, and the partition member (13) having a penetration aperture (3e) therein for enabling communication of the main discharging space (3b) with the auxiliary discharging space (3c). A gas discharge display panel according to claim 3, wherein the at least one barrier rib (11, 12) comprises a metal material (11a, 12a) covered with an insulator (lib, 12b) for at least a surface exposed to the discharging space. A gas discharge display panel according to claim 3, wherein the at least one barrier rib (11, 12) and the partition member (13) are integral. A gas discharge display panel according to claim 3, wherein the metal material (13a) of the metal material comprises a substance forming an insulation oxide film when the surface is oxidized. A gas discharge display panel according to claim 4, wherein the metal material (11a, 12a) constituting the at least one barrier rib (11, 12) comprises a substance forming an insulation oxide film when the surface is oxidized. A gas discharge display panel according to claim 6 or 7, wherein the metal material (11a, 12a, 13a) is at least one of metals of Al, Ti, Fe, Ta, W, Mo, Cu, Mg, Ni, Co and Cr and an alloy containing one of said metals. A gas discharge display panel according to claim 3 or 4, wherein the insulator (11b, 12b, 13b) has a first insulation film comprising an oxide of the metal material formed on the surface of the metal material. A gas discharge display panel according to claim 9, wherein the insulator (11b, 12b, 13b) further has a second insulation film formed on a surface of the first insulation film and comprising an inorganic oxide obtained by heating a gel formed by hydrolysis of an organic metal compound or an aqueous solution of an alkali silicate. A gas discharge display panel according to claim 3 or 4, wherein the insulator (11b, 12b, 13b) is an inorganic oxide obtained by heating a gel formed by hydrolysis of an organic metal compound or an aqueous solution of an alkali silicate. A gas discharge display panel according to claim 7, wherein a surface of the fluorescent layer (14) comprises an insulation layer made of an insulation material, and the fluorescent layer (14) is provided on a lateral surface of the at least one barrier rib constituting an inner wall of the main discharging space and a surface of the main discharging space partition wall. A display system for a gas discharge display panel comprising a gas discharge display panel according to one of the preceding claims, and a driving system for applying signals to the at least one auxiliary discharge electrode and the at least one main discharge electrode for driving the gas discharge display panel to effect display thereon. A display system according to claim 13, wherein the driving system includes at least one address driver for providing addressing of the display panel, at least one scan driver for providing scanning of the display panel, at least one pulse generator for providing pulses for the display panel, and a control unit providing control of the at least one address driver, at least one scan driver and at least one pulse generator for controlling display of the display panel. A partition member (13) for a gas discharge display panel according to one of claims 1 - 12. A method of manufacturing a gas discharge display panel comprising the steps of: forming a back substrate (2) having at least two auxiliary discharging electrodes (9a, 9b) thereon which are arranged in a matter that if in the finished gas discharge display panel an AC voltage is applied between two adjacent auxiliary discharge electrodes (9a, 9b), auxiliary discharging occurs; forming a front substrate (1) having at least two main discharging electrodes (5a, 6a, 5b, 6b) thereon which are arranged in a manner that if in the finished gas discharge display panel a voltage is applied to a first one of the main discharge electrodes (5b, 6b) and an AC voltage is applied to a second one of the main discharge electrodes (5a, 6a), and if at the same time auxiliary discharging occurs, then main discharging is caused; forming a partition member (13) of a metal material (13a); spacing the front substrate (1) and back substrate (2) from one another so as to delimit a gap therebetween; and placing the partition member (13) so as to extend substantially parallel to and between the front and back substrates (1, 2) so as to form a main discharge space (3d) on a front substrate side and an auxiliary discharge space (3c) on a back substrate side. A method of manufacturing a gas discharge display panel according to claim 16, wherein the partition member forming step comprises shaping a substrate made of a metal material into a discharging space separation partition wall (13) having perforation apertures and at least one barrier rib (11, 12) connected with the partition wall (13) for partitioning at least one of the main discharge space (3d) and the auxiliary discharge space (3c). A method of manufacturing a gas discharge display panel according to claim 17, further comprising the steps of: insulating by covering at least a portion of the shape product with an insulator (lib, 12b, 13b) thereby forming the discharging separation partition wall and the at least one barrier rib; forming a fluorescent layer (14) on at least a portion of the discharging separation partition wall (13) and a surface of the at least one barrier rib (11, 12); and assembling by laminating the back substrate (2), the partition member (13) and the front substrate (1) in this order, and serving a lateral surface of the laminate with sealing material. A method of manufacturing a gas discharge display panel according to claim 18, wherein the shaping step includes fabricating the substrate by at least one of etching, laser fabrication, mold shaping and machining. A method of manufacturing a gas discharge display panel according to claim 18, wherein the insulating step includes covering the surface of the shaping product with a gel obtained by hydrolysis of an organic metal compound or an aqueous solution of an alkali silicate, and applying a heat treatment thereby forming a film of a metal oxide as the insulator. A method of manufacturing a gas discharge display panel according to claim 18, wherein the insulating step includes forming an oxide film as an oxide of the metal material (11a, 12a, 13a) on the surface of the shaping product as the insulator (11b, 12b, 13b). A method of manufacturing a gas dischare display panel according to claim 21, wherein the insulating step further includes covering the surface of the oxide film formed on the surface of the shaping product with a gel obtained by hydrolysis of an organic metal compound or an aqueous solution of an alkali metal silicate, applying a heat treatment and forming a film of a metal oxide. A method of manufacturing a gas discharge display panel according to claim 18, wherein the fluorescent layer forming step further includes coating at least a surface of the fluorescent layer (14) in the layer of the partition wall substrate with a gel obtained by hydrolysis of an organic metal compound or an aqueous solution of an alkali silicate, applying a heat treatment thereby forming a film of the metal oxide.

Inventors: MATSUZAKI EIJI, TAKAI TERUO, TSUCHIDA SEIICHI, USHIFUSA NOBUYUKI, MATSUZAKI, EIJI, TAKAI, TERUO, TSUCHIDA, SEIICHI, USHIFUSA, NOBUYUKI
Applicants: HITACHI LTD, HITACHI, LTD.
Application year: 1997
Main classification: H01J17
IPC codes: H01J17, H01J9, H01J11