United States Patent (19) 11) 4,114,064 Ernsthausen 45) Sep. 12, 1978

54 MULTIPLEGASEOUS DISCHARGE Walter H. Kohl, Reinhold Publishing Corp., New DISPLAYAMEMORY PANEL HAVING York, N.Y. 1962, pp. 24, 53, 54, 72-75. IMPROVED VOLTAGE CHARACTERISTICS Primary Examiner-Palmer C. Demeo 75 Inventor: Roger E. Ernsthausen, Luckey, Ohio Attorney, Agent, or Firm-Donald K. Wedding; Myron 73) Assignee: Owens-Illinois, Inc., Toledo, Ohio E. Click; David H. Wilson (21) Appl. No.: 293,817 (57) ABSTRACT 22 Filed: Oct. 2, 1972 There is disclosed a multiple gaseous discharge dis play/memory panel having an electrical memory and Related U.S. Application Data capable of producing a visual display, the panel being (63) Continuation-in-part of Ser. No. 60,376, Aug. 3, 1970, characterized by an ionizable gaseous medium in a gas abandoned. chamber formed by a pair of opposed dielectric material 51 Int. C.’...... H01J 61/30; H01J 61/35 charge storage members which are respectively backed 52 U.S. C...... 313/188; 313/201; by an array of electrode (conductor) members such that 313/220; 313/221 each array of electrode members is insulated from the 58) Field of Search ...... 313/188,221, 220, 201 gaseous medium by a dielectric member, the electrode members behind each dielectric material member being 56) References Cited oriented with respect to the electrode members behind U.S. PATENT DOCUMENTS the opposing dielectric material member so as to define 2,020,727 11/1935 Gaidies et al...... 313/213 a plurality of discrete discharge volumes, each dis 3,189,781 6/1965 Lempert ...... 313/68 RX charge volume constituting a discharge unit, the dielec 3,499,167 3/1970 Baker et al...... 313/188X tric material being selectively enriched with at least one 3,559,190 1/1971 Bitzer et al...... 313/201 X Group IA or IIA element in an amount sufficient to 3,846,171 11/1974 Byrum, Jr. et al...... 313/188 X provide operating voltages which are substantially uni 3,863,089 1/1975 Ernsthausen et al...... 313/188 X form and which do not significantly change with time. OTHER PUBLICATIONS "Materials and Techniques for Electron Tubes, " by 3 Claims, 5 Drawing Figures

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2 4,114,064 2 Proceeding of the Fall Joint Computer Conference, MULTIPLE GASEOUS DESCHARGE IEEE, San Francisco, California, Nov. 1966, pages DISPLAY/MEMORY PANEL HAVING 541-547. Also reference is made to U.S. Letters Pat, No. 3,559,190. : . IMPROVED volTAGE CHARACTERISTICs In the construction of the panel, a continuous volume RELATED APPLICATION of ionizable gas is confined between a pair of dielectric This is a continuation in part of copending U.S. pa surfaces backed by conductor arrays typically forming tent application Ser. No. 60,376, filed Aug. 3, 1970, and matrix elements. The cross conductor arrays may be now abandoned. orthogonally related (but any other configuration of O conductor arrays may be used) to define a plurality of THE INVENTION opposed pairs of charge storage areas on the surfaces of This invention relates to novel multiple gas discharge the dielectric bounding or confining the gas. Thus, for a display/memory panels which have an electrical mem conductor matrix having H rows and C columns the ory and which are capable of producing a visual display number of elemental discharge cells will be the product or representation of data such as numerals, letters, tele 15 H X C and the number of elemental or discrete areas vision display, radar displays, binary words, etc. More will be twice the number of such elemental discharge particularly, this invention relates to novel gas dis cells. charge display/memory panels having substantially In addition, the panel may comprise a so-called uniform operating voltages; that is, essentially stable as monolithic structure in which the conductor arrays are a function of operating time. As used herein, voltage is 20 created on a single substrate and wherein two or more defined as any voltage required for operation of the arrays are separated from each other and from the gase panel including firing and sustaining voltages as well as ous medium by at least one insulating member. In such any other voltages for manipulation of the discharge. a device the gas discharge takes place not between two Multiple gas discharge display and/or memory panels opposing electrodes, but between two contiguous or of one particular type with which the present invention 25 adjacent electrodes on the same substrate; the gas being is concerned are characterized by an ionizable gaseous confined between the substrate and an outer retaining medium, usually a mixture of at least two gases at an wall. appropriate gas pressure, in a thin gas chamber or space It is also feasible to have a gas discharge device between a pair of opposed dielectric charge storage wherein some of the conductive or electrode members members which are backed by conductor (electrode) 30 are in direct contact with the gaseous medium and the members, the conductor members backing each dielec remaining electrode members are appropriately insu tric member typically being appropriately oriented so as lated from such gas, i.e., at least one insulated electrode. to define a plurality of discrete gas discharge units or In addition to the matrix configuration, the conductor cells. arrays may be shaped otherwise. Accordingly, while In some prior art panels the discharge cells are addi 35 the preferred conductor arrangement is of the crossed tionally defined by surrounding or confining physical grid type as discussed herein, it is likewise apparent that structure such as apertures in perforated glass plates and where a maximal variety of two dimensional display the like so as to be physically isolated relative to other patterns is not necessary, as where specific standardized cells. In either case, with or without the confining phys visual shapes (e.g., numerals, letters, words, etc.) are to ical structure, charges (electrons, ions) produced upon be formed and image resolution is not critical, the con ionization of the elemental gas volume of a selected ductors may be shaped accordingly, i.e., a segmented discharge cell, when proper alternating operating po display. tentials are applied to selected conductors thereof, are The gas is one which produces visible light or invisi collected upon the surfaces of the dielectric at specifi ble radiation which stimulates a phosphor (if visual cally defined locations and constitute an electrical field 45 display is an objective) and a copious supply of charges opposing the electrical field which created them so as to (ions and electrons) during discharge. terminate the discharge for the remainder of the half In prior art, a wide variety of gases and gas mixtures cycle and aid in the initiation of a discharge on a suc have been utilized as the gaseous medium in a gas dis ceeding opposite half cycle of applied voltage, such charge device. Typical of such gases include CO; CO; charges as are stored constituting an electrical memory. 50 halogens; nitrogen; NH; oxygen, water vapor; hydro Thus, the dielectric layers prevent the passage of gen; hydrocarbons; PO; boron fluoride, acid fumes; substantial conductive current from the conductor TiCl; Group VIII gases; air; H.O.; vapors of sodium, members to the gaseous medium and also serve as col mercury, thallium, cadmium, rubidium, and cesium; lecting surfaces for ionized gaseous medium charges carbon disulfide, laughing gas; HS; deoxygenated air; (electrons, ions) during the alternate half cycles of the 55 phosphorus vapors; ;CH, CH; naphthalene vapor; A.C. operating potentials, such charges collecting first anthracene; freon; ethyl alcohol; methylene bromide; on one elemental or discrete dielectric surface area and heavy hydrogen; electron attaching gases; sulfur hexa then on an opposing elemental or discrete dielectric fluoride; tritium; radioactive gases; and the rare or inert surface area on alternate half cycles to constitute an gases. electrical memory. In one preferred embodiment hereof the medium An example of a panel structure containing non comprises at least one rare gas, more preferably at least physically isolated or open discharge cells is disclosed two, selected from helium, neon, argon, krypton, or in U.S. Letters Pat. No. 3,499,167 issued to Theodore C. XCO. Baker, et al. In an open cell Baker, et al. type panel, the gas pres An example of a panel containing physically isolated 65 sure and the electrical field are sufficient to laterally cells is disclosed in the article by D. L. Bitzer and H. G. confine charges generated on discharge within elemen Slottow entitled "The Plasma Display Panel - A Digi tal or discrete dielectric areas within the perimeter of tally Addressable Display With Inherent Memory", such areas, especially in a panel containing non-isolated 4,114,064 3. 4. discharge cells. As described in the Baker, et al. patent, internal cell wall voltage in combination with externally the space between the dielectric surfaces occupied by originated voltages. the gas is such as to permit photons generated on dis An "addressing voltage" is a voltage produced on the charge in a selected discrete or elemental volume of gas panel X-Y electrode coordinates such that at the se to pass freely through the gas space and strike surface 5 lected cell or cells, the total voltage applied across the areas of dielectric remote from the selected discrete cell is equal to or greater than the firing voltage volumes, such remote, photon struck dielectric surface whereby the cell is discharged. areas thereby emitting electrons so as to condition at A "writing voltage" is an addressing voltage of suffi least one elemental volume other than the elemental cient magnitude to ensure that on subsequent sustaining volume in which the photons originated. O voltage half cycles, the cell will be in the on state. With respect to the memory function of a given dis In the operation of a multiple gaseous discharge de charge panel, the allowable distance or spacing between vice, of the type described hereinbefore, it is necessary the dielectric surfaces depends, inter alia, on the fre to condition the discrete elemental gas volume of each quency of the alternating current supply, the distance discharge cell by supplying at least one free electron typically being greater for lower frequencies. 15 thereto such that a gaseous discharge can be initiated While the prior art does disclose gaseous discharge when the cell is addressed with an appropriate voltage devices having externally positioned electrodes for initi signal. - The prior art has disclosed and practiced various ating a gaseous discharge, sometimes called "electrode means for conditioning gaseous discharge cells. less discharge", such prior art devices utilized frequen One such means of panel conditioning comprises a cies and spacing or discharge volumes and operating so-called electronic process whereby an electronic con pressures such that although discharges are initiated in ditioning signal or pulse is periodically applied to all of the gaseous medium, such discharges are ineffective or the panel discharge cells, as disclosed for example in not utilized for charge generation and storage at high British patent specification No. 1,161,832, page 8, lines frequencies; although charge storage may be realized at 25. 56 to 76. Reference is also made to U.S. Letters Pat. No. lower frequencies, such charge storage has not been 3,559,190 and "The Device Characteristics of the utilized in a display/memory device in the manner of Plasma Display Element" by Johnson, et al., IEEE the Bitzer-Slottow or Baker, et al. invention. Transactions On Electron Device, Sept. 1971. How The term "memory margin" is defined herein as ever, electronic conditioning is self-conditioning and is 30 only effective after a discharge cell has been previously - A E conditioned; that is, electronic conditioning involves M. M. = VA2 periodically discharging a cell and is therefore a way of maintaining the presence of free electrons. Accord where Vis the half amplitude of the smallest sustaining ingly, one cannot wait too long between the periodi voltage signal which results in a discharge every half 35 cally applied conditioning pulses since there must be at cycle, but at which the cell is not bi-stable and Vis the least one free electron present in order to discharge and half amplitude of the minimum applied voltage suffi condition a cell. cient to sustain discharges once initiated. Other but Another conditioning method comprises the use of similar memory margin definitions have been utilized in external radiation, such as flooding part or all of the the prior art. 40 gaseous medium of the panel with ultraviolet radiation. It will be understood that the basic electrical phe This external conditioning method has the obvious dis nomenon utilized in this invention is the generation of advantage that it is not always convenient or possible to charges (ions and electrons) alternately storable at pairs provide external radiation to a panel, especially if the of opposed or facing discrete points or areas on a pair of 4. panel is in a remote position. Likewise, an external UV 5 source requires auxiliary equipment. Accordingly, the dielectric surfaces backed by conductors connected to a use of internal conditioning is generally preferred. source of operating potential. Such stored charges re One internal conditioning means comprises using sult in an electrical field opposing the field produced by internal radiation, such as by the inclusion of a radioac the applied potential that created them and hence oper tive material. ate to terminate ionization in the elemental gas volume 50 Another means of internal conditioning, which we between opposed or facing. discrete points or areas of call internal "photon conditioning", comprises using dielectric surface. The term "sustain a discharge" means one or more so-called pilot discharge cells in the on producing a sequence of momentary discharges, at least state for the generation of photons. This is particularly one discharge for each half cycle of applied alternating effective in a so-called open cell construction (as de sustaining voltage, once the elemental gas volume has 55 scribed in the Baker, et al. patent) wherein the space been fired, to maintain alternate storing of charges at between the dielectric surfaces occupied by the gas is pairs of opposed discrete areas on the dielectric sur such as to permit photons generated on discharge in a faces. selected discrete or elemental volume of gas (discharge As used herein, a cell is in the "on state" when a cell) to pass freely through the panel gas space so as to quantity of charge is stored in the cell such that on each 60 condition other and more remote elemental volumes of half cycle of the sustaining voltage, a gaseous discharge other discharge units. In addition to or in lieu of the is produced. pilot cells, one may use other sources of photons inter In addition to the sustaining voltage, other voltages nal to the panel. may be utilized to operate the panel, such as firing, In accordance with this invention, it has been surpris addressing, and writing voltages. 65 ingly discovered that the voltage uniformity as a func A "firing voltage" is any voltage, regardless of tion of operating time of a gaseous discharge panel may source, required to discharge a cell. Such voltage may be significantly enhanced and improved by the selective be completely external in origin or may becomprised of addition of at least one Group IA or IIA element to the 4,114,064 5 6 dielectric material. More particularly, at least one ele chromate, potassium citrate, potassium cyanate, potas ment selected from Group IA or IIA is selectively sium cyanide, potassium fluogermanate, potassium fluo added into the panel dielectric material before curing in rescein derivative, potassium picrate, potassium hydro an amount sufficient to provide gaseous discharge panel gen phthalate, potassium piperate, potassium propio operating voltages which are uniform and which do not nate, potassium salicylate, potassium santoninate, potas significantly vary or substantially change over a given sium stearate, potassium succinate, potassium fluotho period of operating time. rate, potassium fluotitanate, potassium formate, potas As used herein Group IA element is defined as in sium hydride, KOH, potassium lactate, potassium lau cluding lithium, sodium, potassium, rubidium, cesium, rate, potassium malate, potassium methionate, potas and francium; Group IIA element is defined herein as 10 sium carbonyl, potassium chromate, potassium dichro including beryllium, magnesium, calcium, strontium, mate, potassium peroxychromate, potassium nitrate, barium, and radium. In the practice of this invention it potassium nitride, potassium nitrite, potassium oleate, is contemplated that one or more members of Group IA potassium osmate, potassium oxalate, and potassium or IIA may be used alone or in combination. Likewise, hydrogen oxalate. mixtures of elements from both Group IA and IIA may 15 Likewise, the corresponding compounds of other be used. Possible combinations of elements include Na alkali metals such as sodium and lithium as well as ce and Ca; Na and Mg; Na and Cs; Ca and Ra. sium and rubidium may be used as sources of the respec The Group IA or IIA element may be incorporated tive ion, e.g., sodium, lithium, cesium, and rubidium. into the dielectric by any suitable means, typically by Thus, the cesium source can be elemental cesium or a mixing with the dielectric material batch. Other suitable 20 cesium compound similar to the K compounds noted means of incorporation include not by way of limitation hereinbefore. Examples, not by way of limitation of ion exchange, ion implantation, and diffusion tech cesium compounds, include both organic and inorganic niques. compounds as CsCHO, (cesium acetate), CsC7H5O2 Any source of Group IA or IIA element may be (cesium benzoate), CsbrC) (cesium bromate), Csbr (ce utilized. It is broadly contemplated incorporating into 25 sium monobromide), Csbr (cesium tribromide), the dielectric at least one Group IA or IIA member in CsBrClI (cesium bromochloroiodide), CsIBrCcesium elemental form or as a compound or mineral. Where the dibromoiodide), CsIBr (cesium bromodiiodide), dielectric material is prepared as a glass batch, the CsCO3 (cesium carbonate), CsICO3 (cesium carbonate Group IA or IIA is typically utilized in the form of an hydrogen), CsClO3 (cesium chlorate), CsClO4 (cesium oxide or carbonate. However, dependent upon the 30 perchlorate), CsCl (cesium chloride), CsauCl4 (cesium method of incorporation of the Group IA or IIA mem chloroaurate), CsbrCl (cesium chlorodibromide), ber into the dielectic, other compounds may also be CsBrCl (cesium dichlorobromide), CsICl (cesium di used. chloroiodide), Cs2SnCls (cesium chlorostannate), Thus, typical sources of potassium comprise both CsCrO4 (cesium chromate), CsCn (cesium cyanide), organic and inorganic compounds such as the potassium 35 CsP (cesium fluoride), CsCHO, (cesium formate), oxides including K2O, K2O, K2O3, and KO.; the potas CsCHO.HO, CsH (cesium hydride), CsOH (cesium sium carbonates including K2CO3, potassium hydrogen hydroxide), CsIO (cesium iodate), CsIO (cesium meta carbonate, potassium trithiocarbonate, potassium periodate), CsI (cesium monoiodide), CsI(cesium trio peroxy-carbonate; potassium sulfates including KSO, dide), CsIs (cesium pentaiodide), CsCls, CsBris, CsPs, potassium hydrogen sulfate, potassium ethyl sulfate, 40 CSNO (cesium nitrate), CsNOHNO (cesium hydro potassium phenyl sulfate, potassium propyl sulfate, po gen nitrate), CsNO2HNO (cesium dihydrogen ni tassium pyrosulfate, potassium fluosulfonate, potassium trate), CsNO (cesium nitrite), CsCO4(cesium oxalate), methylsulfate, potassium thiosulfate, potassium peroxy CsO (cesium monoxide), Cs2O, (cesium peroxide), disulfate; potassium sulfides including KS, KHS, potas Cs;O, (cesium trioxide), Cso, (cesium superoxide), sium disulfide, potassium trisulfide, KHSO, potassium 45 CsICHO (cesium hydrogen phthalate), tetrasulfide, potassium pentasulfide; potassium halides CsRh(SO)12H2O (cesium rhodium sulfate), and halogen compounds including KF, KC, KBr, KI, CsCHO (cesium salicylate), Cs,SO4 (cesium sulfate), KHF, KHCl2, KHBr, KHI, KF, KCl, KBr, KI CsHSO4 (cesium hydrogen sulfate), Cs,S.4H2O (cesium KIBr, KClO3, KClO, KCIO, KICl4, KICl potassium sulfide), CsS (cesium disulfide), Cs2S2.H2O, Cs2S3 (ce chloroosmate, potassium pentachlorohodite, KBF, 50 sium tetrasulfide), Cs2S5 (cesium pentasulfide), Cs2S6 KIO, KIO, KIBr2, KSnBr, potassium penta (cesium hexasulfide). chlorohodite; potassium phosphates such as KPO, The rubidium source can be elemental rubidium or a potassium phenyl phosphate KHPO, KPO, potassium rubidium compounds, e.g., similar to the potassium and pyrophosphate, potassium hexafluorophosphate, cesium compounds noted hereinbefore. Examples, not KHPO3, KHPO, potassium glycerophosphate; other 55 by way of limitation of rubidium compounds, include organic and inorganic compounds include potassium both organic and inorganic compounds such as saccharate acid, potassium hydrogen succinate, potas RbCHO, (rubidium acetate), RbAl(SO4)2.12H2O (ru sium d - tartrate, potassium orthotellurate, potassium bidium aluminum sulfate), RbBrO (rubidium bromate), thiocyanate, potassium dithionate, potassium trithio RbBr (rubidium bromide), RbBr (rubidium tribro nate, potassium tetrathionate, potassium pentathionate, 60 mide), RbBrCl (rubidium bromochloroiodide), RbBr? potassium acid urate, potassium acetate, potassium acid (rubidium dibromoiodide), RbBrCl (rubidium di acetate, potassium amide, potassium acetylsalicylate, chlorobromide), RbBrCl (rubidium chlorodibromide), potassium azide, potassium ammonium tartrate, RbCO (rubidium carbonate), RbHCO3, RbC1O (ru KAuO, potassium benzoate, potassium diborane, potas bidium chloroate), RbC1O (rubidium perchlorate), sium dihydroxy diborane, potassium pentaborane, po 65 RbCl (rubidium chloride), RbCl (rubidium dichloroio tassium metaborate, potassium tetraborate, potassium dide), RbCrO (rubidium chromate), RbCrO, (rubid pentaborate, potassium peroxyborate, potassium bro ium dichromate), RbF (rubidium fluoride), Rb2SiF6 mate, potassium borotartrate, potassium chromium (rubidium fluosilicate), RbFSO (rubidium fluosulfon 4,114,064 7 8 ate), RbH (rubidium hydride), RbCH (rubidium hy electric is in addition to the Group IA or IIA oxide droxide), RbL) (rubidium iodate), RbIO (rubidium selectively added to the uncured dielectric. metaperiodate), Rb (rubidium iodide), Rb (rubidium Depending upon the specific Group IA or IIA ele triiodide), RbI SO, RbMnO4 (rubidium permanga ment or combinations thereof utilized, the practice of nate), RbNO (rubidium nitrate), RbNOHNO (rubid this invention has been found to be especially beneficial ium hydrogen nitrate), RbNO2HNO3, RbCl (rubid over given periods of operating time. Best results are ium superoxide), Rb2SO4 (rubidium sulfate), RbHSO typically realized after appropriate aging of the panel, (rubidium hydrogen sulfate), Rb2S (rubidium monosul the required amount of aging being a function of the fide), RbS.4HO, Rb2S (rubidium disulfide), RbS: specific Group IA or IIA members incorporated into (rubidium trisulfide), Rb2S (rubidium pentasulfide), 10 the panel dielectric material. As used herein, panel Rb2S6 (rubidium hexasulfide), RbHCHO, Rb2O, (ru aging is defined as total or accumulated panel operating bidium peroxide). time. Specific sources of sodium or lithium ion would in Tables II to IX are presented hereafter as working clude elemental sodium and lithium as well as com examples and best embodiments contemplated by the pounds of all the classes listed for potassium, cesium, 5 inventor for the practice of this invention. Table I rep and rubidium hereinbefore, particularly the oxides and resents a standard or prior art dielectric not prepared in carbonates. accordance with this invention. In each table the dielec Likewise, alloys or ceramics containing one or more tric composition is given before and after curing. of the Group IA elements may be employed. In the preparation of the standard dielectric of Table Specific sources of the Group IIA metals include the 20 I no Group IA or IIA element was added to the un metals in an elemental state as well as organic and inor cured dielectric. In the dielectrics of Tables II to IX ganic compounds including the acetates, amides, bo varying amounts (within the 0.5 to 8 wt.% range) were rides, bromates, halides (including chlorides, iodides, added to the uncured dielectric compositions. The di bromides, fluorides), oxyhalides, carbonates, chlorates, electric curing conditions for all compositions (I to IX) chromates, citrates, hydrides, sulfides, sulfates, hypo 25 were about the same, 1125 F. curing temperature for chlorites, nitrates, nitrites, oxides, silicates, aluminates about 30 minutes. of berryllium, magnesium, calcium, barium, and stron A gas discharge device utilizing the standard dielec tium. rt tric of Table I exhibited operating voltage changes of As already noted the Group IA or IIA element is about 10 volts whereas the dielectrics of Tables II to IX selectively enriched into the dielectric before curing in 30 exhibited significantly less voltage changes. This is illus a small effective amount sufficient to provide stable trated by FIG. 1 of the drawing which plots the results operating voltages over a given period of panel operat of Tables I, II, III, and IV. ing time. Typically, the Group IA or IIA element is More specifically, there is shown in FIG. 1 four sepa selectively added into the uncured dielectric in a quan 35 rate dielectric curves on a plot of change in voltage (A tity of about 0.5% to about 8% by weight in the oxide V) versus accumulated panel operating time in hours. state of the element based on the total weight of the All curves illustrate that a minimum amount of aging, dielectric composition before curing. Preferably the e.g., up to about 300 hours, is required for any particular quantity of element selectively added into the dielectric dielectric compositions. Thereafter the performance of before curing is about 1% to about 4% by weight of the 40 II, III, and IV in terms of less voltage change is im element in the oxide state. proved relative to I (the standard dielectric). In the fabrication of a gaseous discharge panel, the TABLE I dielectric material is typically applied and cured on the Standard Dielectric Composition surface of a glass substrate. When the glass substrate Component Before Cure After Cure contains significant amounts of Group IA or IIA ele 45 SiO, 13.43 wt.% 15.50 wt.% ments, an ion exchange, migration, diffusion, or other PbO 73.40 69.90 BO 13.20 12.63 reaction effect may take place thereby adding to the NaO 0.005 126 total amount of Group IA or IIA previously incorpo CaO. 0.59 rated in the dielectric, e.g., added as an oxide or carbon 100.03 wt.% 99.88 wit. 26 ate to the dielectric batch. Such additional amounts, 50 present after the dielectric is cured in contact with the substrate, are not included in the above quantity ranges. TABLE II Thus, it is contemplated that the substrate glass may be 1.88% wt.% Sodium Oxide Added to Dielectric Composition. Before Cure the partial source of the Group IA or IIA element in the Component Before Cure After Cure cured dielectric by means of an ion exchange, migra 55 SiO, 13.3 wt.% 14.25 wt.% tion, diffusion, or other reaction process. PbO 718O 68.90 The amount of Group IA or IIA oxide transferred BO 12.81. 12.56 from the substrate to the cured dielectric is a function of NaO 188 2.50 CaO - 0.39 the dielectric curing temperature, the time period of 99.62 wt.% 98.60 wt.% heating, the amount and kind of Group IA or IIA oxide 60 in the substrate and dielectric before curing, and other variables. In any event, the amount of Group IA or IIA TABLE III oxide transferred from the substrate to the cured dielec 3.63 wt.% Sodium Oxide Added to tric is less than about 5 percent by weight based on the Dielectric Composition Before Cure total weight of the cured dielectric. This transferred 65 Component Before Cure After Cure amount is not considered in the range of selectively SiO, 13.22 wt.% 17.75 wt.% BO 13.05 12.28 added Group IA or IIA element; that is, any Group IA PbO 69.95 64.30 or IIA oxide transferred from the substrate to the di NaO 3.63 4.86 4,114,064 9 10 TABLE III-continued TABLE IX-continued 3.63 wt.% Sodium Oxide Added to 0.89 wt.% LiO Added To Dielectric Composition. Before Cure Dielectric Composition. Before Cure Component Before Cure After Cure Component Before Cure After Cure CaO - 0.84 5 NaO 0.0068 2.89 99.85 wt.% 100,03 wt.% LiO 0.89 0,007 CaO -r 0.56 99.32 wit. 9% 99.11 wt.% TABLE IV .97 wt.% Cso Added To 10 Reference is made to the following detailed descrip Dielectric Composition Before Cure tion of FIGS. 2 to 5 of the drawings. Component Before Cure After Cure FIG. 2 is a particularly cut-away plan view of a gase SiO, 13.30 wt.% 14.05 wt.% ous discharge/memory panel as connected to a dia PbO 72.75 71.50 BO 12.87 2.80 grammatically illustrated source of operating potentials, NaO 0.04 0.67 15 FIG. 3 is a cross-sectional view (enlarged, but not to CsO 0.97 0,98 proportional scale since the thickness of the gas volume, CaO --- 0.34 dielectric members and conductor arrays have been 99.93 wt.% 100.34 wt.% enlarged for purposes of illustration) taken on lines 2 2 of FIG. 2, TABLE V 20 FIG. 4 is an explanatory partial cross-sectional view 7.98 wt.% Cso Added To similar to FIG. 3 (enlarged, but not to proportional Dielectric Composition Before Cure scale), Component Before Cure After Cure FIG. 5 is an isometric view of a gaseous discharge SiO, 12.48 wt.% 3.67 wt.% display/memory panel. BO 12.14 11.97 25 PbO 66.85 64.20 The invention utilizes a pair of dielectric films 10 and NaO 0.026 0.80 11 separated by a thin layer or volume of a gaseous Cs,O 7.98 8.20 discharge medium 12, the medium 12 producing a copi CaO - 0.46 ous supply of charges (ions and electrons) which are 99.48 wt.% 99.30 wt.% alternately collectable on the surfaces of the dielectric 30 members at opposed or facing elemental or discrete TABLE VI areas X and Y defined by the conductor matrix on non 2.32 wt.% CaO. Added to gas-contacting sides of the dielectric members, each Dielectric Composition Before Cure dielectric member presenting large open surface areas Component Before Cure After Cure and a plurality of pairs of elemental X and Y areas. SiO, 13.33 wt.% 14.67 wt.% 35 While the electrically operative structural members PbO 71.65 68.20 such as the dielectric members 10 and 11 and conductor BO 12.85 12.65 NA6 0.009 0.867 matrixes 13 and 14 are all relatively thin (being exagger CaO 2.32 2.69 ated in thickness in the drawings) they are formed on 100, 15 wt.% 99.08 wit. 2, and supported by rigid nonconductive support mem 40 bers 16 and 17 respectively. Preferably, one or both of nonconductive support TABLE VII members 16 and 17 pass light produced by discharge in 5.41 wt.% CaO. Added To Dielectric Composition. Before Cure the elemental gas volumes. Preferably, they are trans Component Before Cure After Cure parent glass members and these members essentially SiO, 12.52 wt.% . 14.19 wt.% 45 define the overall thickness and strength of the panel. PbO 70.20 67.25 For example, the thickness of gas layer 12 as determined BO 11.90 1.79 by spacer 15 is usually under 10 mils and preferably NaO 0.014 0.80 CaO 5.4 5.64 about 4 to 6 mils, dielectric layers 10 and 11 (over the 100.03 wt.% 99.67 wt.% conductors at the elemental or discrete X and Y areas) 50 are usually between 1 and 2 mils thick, and conductors 13 and 14 about 8,000 angstroms thick. However, sup TABLE VIII port members 16 and 17 are much thicker (particularly 3.76 wt.% MgO Added To in larger panels) so as to provide as much ruggedness as Dielectric Composition. Before Cure may be desired to compensate for stresses in the panel. Component Before. Cure After Cure 55 Support members 16 and 17 also serve as heat sinks for SiO, 13.2 wt.% 14.70, wt.% PbO 70.75 66.85 heat generated by discharges and thus minimize the BO 12.55 12.90 effect of temperature on operation of the device. If it is NaO 0.007 1.00 MgO 3.76 3.86 desired that only the memory function be utilized, then CaO - 0.32 none of the members need be transparent to light. 100.27 wt.% 99.63 wit. 2 60 Except for being nonconductive or good insulators the electrical properties of support members 16 and 17 are not critical. The main function of support members TABLE IX 16 and 17 is to provide mechanical support and strength 0.89 wt.% LiO Added To for the entire panel, particularly with respect to pres Dielectric Composition. Before Cure 65 sure differential acting on the panel and thermal shock. Component Before Cure After Cure As noted earlier, they should have thermal expansion SiO, 13.47 wt.% 6.40 wt.% BO, 12.76 12.36 characteristics substantially matching the thermal ex PbO 72.20 66.90 pansion characteristics of dielectric layers 10 and 11. 4,114,064. 11 12 Ordinary inch commercial grade soda line plate scopic scale (e.g., no cracks, bubbles, crystals, dirt, glasses have been used for this purpose. Other glasses surface films, etc.). In addition, the surfaces of dielectric such as low expansion glass or transparent devitrified layers 10 and 11 should be good photoemitters of elec glass can be used provided they can withstand process trons in a baked out condition. Alternatively, dielectric ing and have expansion characteristics substantially layers 10 and 11 may be overcoated with materials matching expansion characteristics of the dielectric designed to produce good electron emission, as in U.S. coatings 10 and 11. For given pressure differentials and Letters Pat. No. 3,634,719, issued to Roger E. Ernst thickness of plates, the stress and deflection of plates hausen. Of course, for an optical display at least one of may be determined by following standard stress and dielectric layer 10 and 11 should pass light generated on strain formulas (see R. J. Roark, Formulas for Stress and 10 discharge and be transparent or translucent and, prefer Strain, McGraw-Hill, 1954). ably, both layers are optically transparent. Spacer 15 may be made of the same glass material as The preferred spacing between surfaces of the dielec dielectric films 10 and 11 and may be an integral rib tric films is about 4 to 6 mils with conductor arrays 13 formed on one of the dielectric members and fused to and 14 having center-to-center spacing of about 17 mils. the other members to form a bakeable hermetic seal 15 The ends of conductors 14-1 . . . 14-4 and support enclosing and confining the ionizable gas volume 12. member 17 extend beyond the enclosed gas volume 12 However, a separate final hermetic seal may be effected and are exposed for the purpose of making electrical by a high strength devitrified glass sealant. 15S. Tubula connection to interface and addressing circuitry 19. tion 18 is provided for exhausting the space between Likewise, the ends of conductors 13-1 ... 13-4 on sup dielectric members 10 and 11 and filling that space with port member 16 extend beyond the enclosed gas volume the volume of ionizable gas. For large panels small 12 and are exposed for the purpose of making electrical beadlike solder glass spacers such as shown at 15B may connection to interface and addressing circuitry 19. be located between conductor intersections and fused to As in known display systems, the interface and ad dielectric members 10 and 11 to aid in withstanding dressing circuitry or system 19 may be relatively inex stress on the panel and maintain uniformity of thickness 25 pensive line scan systems or the somewhat more expen of gas volume 12. sive high speed random access systems. In either case, it Conductor arrays 13 and 14 may be formed on sup is to be noted that a lower amplitude of operating poten port members 16 and 17 by a number of well-known tials helps to reduce problems associated with the inter processes, such as photoetching, vacuum deposition, face circuitry between the addressing system and the stencil screening, etc. In the panel shown in FIG. 5, the 30 display/memory panel, per se. Thus, by providing a center-to-center spacing of conductors in the respective panel having greater uniformity in the discharge char arrays is about 17 mils. Transparent or semi-transparent acteristics throughout the panel, tolerances and operat conductive material such as tin oxide, gold or aluminum ing characteristics of the panel with which the interfac can be used to form the conductor arrays and should ing circuitry cooperate, are made less rigid. have a resistance less than 3000 ohms per line. Narrow 35 I claim: opaque electrodes may alternately be used so that dis 1. In a gaseous discharge display/memory device charge light passes around the edges of the electrodes to comprising an ionizable gaseous medium in a gas cham the viewer. It is important to select a conductor mate ber formed by a pair of opposed dielectric material rial that is not attacked during processing by the dielec members backed by electrode members, the electrode tric material. . . . . 40 members behind each dielectric material surface being It will be appreciated that conductor arrays 13 and 14 transversely oriented with respect to the electrode may be wires or filaments of copper, gold, silver or members behind the opposing dielectric material sur aluminum or any other conductive metal or material. face so as to define a plurality of discharge units, said For example 1 mill wire filaments are commercially dielectric material surfaces serving to store charges available and may be used in the invention. However, 45 during each half-cycle of operation, the improvement formed in situ conductor arrays are preferred since they wherein each dielectric member is selectively enriched may be more easily and uniformly spaced on and ad with at least one element selected from the group con hered to the support plates 16 and 17. sisting of lithium, sodium, potassium, rubidium, cesium, Dielectric layer members 10 and 11 are formed of an francium, beryllium, magnesium, calcium, strontium inorganic material and are preferably formed in situ as 50 and barium in an amount sufficient to provide gas dis an adherent film or coating which is not chemically or charge device operating voltages which are substan physically effected during back-out of the panel. One tially uniform and which do not significantly change such material is a solder glass such as Kimble SG-68 with time after a period of aging. manufactured by and commercially available from the 2. The invention of claim 1 wherein each dielectric assignee of the present invention. 55 member is selectively enriched with about 0.5 weight This glass has thermal expansion characteristics sub percent to about 8 weight percent of the element in the stantially matching the thermal expansion characteris oxide state based on the total weight of the dielectric. tics of certain soda-lime glasses, and can be used as the 3. The invention of claim 1 wherein each dielectric dielectric layer when the support members 16 and 17 member is selectively enriched with about 1 weight are soda-lime glass plates. Dielectric layers 10, and 11 60 percent to about 4 weight percent of the element in the must be smooth and have a dielectric strength of about oxide state based on the total weight of the dielectric. 1000 v. and be electrically homogeneous on a micro st xx sk k

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