US3896327A - Monolithic gas discharge display device - Google Patents

Abstract

There is disclosed a gas discharge device having an inherent memory wherein all electrically operative elements are formed on a common support substrate. The device comprises a monolithic panel structure in which the conductor arrays are created on a single substrate and wherein two or more arrays are separated from each other and from the gaseous medium by at least one insulating member. In such a device the gas discharge takes place not between two opposing members, but between two contiguous or adjacent members on the same substrate. Each discharge is isolated, e.g., via cavities, such that the resolution is improved.

Description

United States Patent Schermerhorn 1 July 22, 1975 [5 MONOLITHIC GAS DISCHARGE DISPLAY 3,686,686 8/1972 Hall 315/169 R x DEVICE 3, 99,377 10/1972 Hall et a1... 313/220 x 3,704,386 11/1972 Cola t 313/108 B X Inventor: J y Schermerhorn, Swanwn, 3,764,429 10/1973 Janning 313/1095 x Ohio [73] Assignee: Owens-Illinois, lnc., Toledo, Ohio Primary Examiner-James Lawrence Assistant Examiner-E. R. LaRoche 1 Filed: 1973 Attorney, Agent, or Firm-Donald Keith Wedding [21] Appl. No.: 416,727

Related U.S. Application Data [57] ABSTRACT There is disclosed a gas dlscharge device havmg an 1n- [63] gg sszfggggg t gigjgjgg fil i yigi gg herent memory wherein all electrically operative ele- Set. I110. 197,003, Nov. 9, 1971 Pat. 3 787 ments are formed on a common support substrate. The device comprises a monolithic panel structure in 52 us. (:1. 313/220; 313/201; 313/217; which the chdhcto arrays are Created a Single 313/493; 315/169 TV substrate and wherem two or more arrays are sepa- 51 1m. 01 HOlj 11/02; 1101 61/30 rated from h and from the gaseous "'F [58] Field of Search 315/169 R, 169 TV; by at least he1hshlahhg memhersuch a the 313/108 B, 109.5 217 220 20], 493 gas discharge takes place not between two opposing members, but between two contiguous or adjacent [56] References (:ited Inergbers on the same substlratg. Eahch disclharge is isoate e.g., via cav1t1es, suc t at t e reso utlon 1s 1m- UNITED STATES PATENTS proved 3.553.458 1/1971 Schagen 315/169 x 3,678,322 7/1972 Souri 313/217 x 7 Claims, 6 Drawing Figures 7& 60/1/01) 0! 1 or THEiNvEN'rION This invention r relates to multiple .gas discharge devic'es, especially multiple gas discharge display/memory panels or units which. have an electrical memory and which are capable of producing. a visual display or representation of datasuch as numerals. letters, radar displays; aircraft displays binary words, educational displays, television, :etd More particularly,thisinvention relatesto a monolithically structured multiple'gaseous discharge display/memory panel wherein the conductors orelectrodesrbfbr carrying gaseous discharge conina thin gaschamber or space between a=pair of opposed dielectric chargexstorage memberswhich are backed by conductor (electrode) members, the conductor members backing-each dielectric member typically being appropriately oriented so aszto define aplurality of i discrete discharge volumest eacht constituting asdischarge'unit. t 'm 1 1,;

it In some other 'prior art panels,the= discharge'iinits are additionally defined by surrounding or confining physical structure such asby cells or apertures in perforated glass plates andthelilte' so as to be' physically isolated relativ' to othger unitsvw a; *w i 1 An example of a panel containing physically isolated units is disclosed in the article by 'D. L. Bitzer and H. GjSlottow entitled The Plasma Display Panel A DigitallyAddress'able Display With Inherent Memory,

Proceedingof the Falluloiht Computer Conference IEEE, SanFrancisco; Calift; Novtl966',pp; 541-547.

Alsoreferenee ismade to hereinbefore (EilfidULSl Pat. No'. 3,559,190 issued to Bitzer, et alw i r 1 In either case,='with 'orwitliout the confinin'g physical structure; charges (electrons, ions) produced uponLionization 'of the gas of a selected discharge unit, when proper alternating operating potentials are applied to selected conductorsthereofi are collected upon the surfaces of th'e dielectric at specifically defined locations and constitute anelectriCal field opposing the electrical field which created them so as to terminate the discharge for the remainderof the half cycleand I aid in the initiation of a discharge on a succeeding opposite half cycle of applied voltage, such charges as are stored constituting an electrical memory.

Thus, the dielectric layers prevent the passage of substantial conductive current fr m the conductor members to the gaseous medium and also serve as collecting surfaces for ionized gaseous medium charges (electrons, ions) during the alternatehalf cycles of the A.C. operating potentials, such charges collecting first on 5 one elemental or discrete dielectric. surface area and then on an opposing elemental or discrete dielectric surface area on alternate half cycles to constitute an electrical memory. i

In the operation of a gas discharge display/memory ili'oipane'lua continuous volume of ionizable gas is confined between a pain of dielectric surfaces backed by conductor arrays typically forming matrix elements. The cross conductor arrays may be orthogonally related (but any other configuration of conductor arrays may be used) to define a plurality of opposed pairs of charge storage areas on the surfaces of the dielectric bounding or confining the gas. Thus, for a conductor matrix having H- rows and C-columns the number of elemental dis charge volumeswill bethe product H X C and the numberiof elemental or discrete areas will be twice the number of elemental discharge volumes.

rln addition to the matrix configuration, the conductor arrays may be shaped otherwise. Accordingly, while thelpreferred conductor arrangement is of the crossed grid type as' discussed herein, it is likewise apparent that where a maximal variety of two dimensional display patterns is notmecessary, as where specific standardized visual shapes (e .g. numerals, letters,words, etc.) are to be formed and imageresolution is not criti cal, the conductors may be shaped accordingly.

In the operation of a multiple gaseous discharge device, of the type described hereinbefore, it is necessary to condition the discrete elemental gas volume of each discharge unitby supplying at least one free electron thereto such that a gaseous discharge can be initiated when the unit isaddressed with an operating voltage signal. i t

The prior art has disclosedand practiced various means for-conditioning gaseous discharge units.

One such method comprises the use of external radiation, such as flooding part or all of the gaseous medium of the panel with ultraviolet radiation. This external conditioning method has the obvious disadvantage that it is not always convenient or possible to provide external radiation to a panel, especially if the panel is in a remote position. Likewise, an external UV source requires auxiliary equipment; Accordingly, the use of internal conditioning is generally preferred.

Furthermore, a variety of electronic conditioning means may be utilized.

One internal conditioning means comprises using internal radiatiomsuch as by the inclusion of a radioaetive material and/or by the use of one or more so-called pilot discharge unit for the generation of photons.

As described in the Baker et al. patent, the space between the dielectric surfaces occupied by the gas is such as to permit photons generated on discharge in a selected discrete of elemental volume of gas (discharge unit) to pass freely through the panel gas space so as to condition other and more remote elemental volumes of other discharge units.

However, such internal photon generation and electron conditioning of the panel gaseous medium may be- 6 come unreliable when a given discharge unit to be addressed is remote in distance (an inch or more) relative to the conditioning source, e.g., the pilot unit; Thus, a multiplicity of pilot units or cells may be required for the conditioning of a panel having a large geometric area.

The gas is one which produces visible light or invisible radiation which stimulates a phosphor (if visual display is an objective) and copious supply of charges (ions and electrons) during discharge.

In an open cell Baker et al. type panel, the gas pressure and the electric field are sufficient to laterally confine charges generated on discharge within elemental or discrete dielectric areas within the perimeter of such areas, especially in a panel containing nonvisolated units. As described in the Baker et al. patent, the space between the dielectric surfaces occupied by the gas is such as to permit photons generated on discharge in a selected discrete or elemental volume of gas to pass freely through the gas space and strike surface areas of dielectric remote from the selected discrete volumes,

such remote, photon struck dielectric surface areas thereby emitting electrons so as to condition other and more remote elemental volumes for discharges at a uniform applied potential.

With respect to the memory function of a given discharge panel, the allowable distance or spacing between the dielectric surfaces depends, inter alia, on the frequency of the alternating current supply, the distance typically being greater for lower frequencies.

While the prior art does disclose gaseous discharge devices having externally positioned electrodes for initiating a gaseous discharge, sometimes called electrodeless discharge, such prior art devices utilized frequencies and spacings or discharge volumes and operating pressures such that although discharges are initiated in the gaseous medium, such discharges are ineffective or not utilized for charge generation and storage at higher frequencies; although charge storage may be realized at lower frequencies, such charge storage has not been utilized in a display/memory device in the manner of the Bitzer-Slottow or Baker, et al. invention.

The term memory margin is defined herein as where V is the half amplitude of the smallest sustaining voltage signal which results in a discharge every half cycle, but at which the cell is not bi-stable and V,.; is the half amplitude of the minimum applied voltage sufficient to sustain discharges once initiated.

It will be understood that the basic electrical phenomenon utilized in this invention is the generation of charges (ions and electrons) alternately storable at discrete points or pairs of opposed or facing discrete points or areas on a dielectric surface or a pair of dielectric surfaces backed by conductors connected'to a source of operating potential. Such stored charges result in an electrical field opposing the field produced by the applied potential that created them and hence operate to terminate ionization in the elemental gas volume between opposed or facing discrete points or areas of dielectric surface. The term sustain a discharge means producing a sequence of momentary discharges, at least one discharge for each half cycle of applied alternating sustaining voltage, once the elemental gas volume has been discharged, to maintain alternate storing of charges at discrete areas or pairs of opposed discrete areas on the dielectric surfaces.

In thefabrication .of a multiple gaseous discharge display/memory panel, the conductor arrays are applied to supporting substrates, typically of a ceramic or glass material.

Thus in the fabrication of a Bakeret al. gas discharge display/memory panel, the respective row and column conductor arrays are applied to glass support plates, a thin dielectric layer or coating then being applied over the conductors in each array. Two or more plates are joined in space relation by a spacer-sealant means so as to form a very thin but large gas discharge chamber which is filled with an operative gas medium.

In a'Bitzer et al. device, there is fabricated a panel structure wherein therespectiverow-column conductor arrays are formed on thin glass plates and a perforated center plate is then sandwiched between the nonconductor surfaces of the thin glass plates with the individual perforations of the centerlplate positioned at the conductor :cross points. so asstob define discretev discharges. I

A number of variations on these two basic approaches for fabrication of gas discharge panel (sometimes called plasma displays) structures have been devised. However, in some prior art devices, the electrically operative elements have been fabricated as separate elements and then assembled in their positionally operative relationship.

In accordance with this invention there is provided a multiple gaseous discharge display/memory panel of a monolithic structure .in'which the conductor arrays are created on a single substrate and wherein two, or more arrays are separated from each other and from the gaseous medium by at least one insulating member. In such a device the gas discharge takes place not between two opposing members, but between two contiguous or adjacent members on :thezsame substrate.

More particularly, in accordance with the present invention, the respective cooperating conductor arrays are formed on and carried by a single common support member, such as a relatively thick non-conductive support substrate. One of the conductor arrays is formed on the surface of the support substrate and then a thin dielectric layer is formed directly on that conductor array. The second conductor array is formed directly on the exposed surface of this dielectric layer to define a plurality of matrix cross points. A plurality of discrete gas cavities, one for each matrix cross point, is formed in or through the dielectric layer, each cavity in electrically operative adjacency to its corresponding matrix cross point. A further dielectric or non-conductive layer or coating is then applied on the structure thus formed so as to assure that the second conductor array as well as any conductors in the first conductor array are dielectrically isolated from or non-conductively coupled to the operative gas medium with which the cavities are to be filled. Thus all of the electrically operative elements are formed monolithically in permanently fixed positional relationship on a common support substrate. Such structure may be mounted in an envelope filled with an operating gas or a viewing plate may be joined to the structure by a spacer sealant element.

The above and other features and advantages of the invention will become apparent when considered with the following specification and accompanying drawings wherein:

FIG. 1 is an isometric view of a monolithically structured gas discharge device incorporating the invention;

FIG. 2 is a partially enlarged sectional view of the support substrate illustrating the monolithicity of the panel;

FIG. 3 is a diagrammatic illustration of an offset location of the discharge cavities with respect to the cross points of the matrix;

FIG. 4 is a diagrammatic illustration of the position of the discharge cavities overlying the bottom or first applied conductor array as shown in FIG. 2;

FIG. 5 is an enlarged cross-sectioned view of a discharge cavity illustrating a modification of the invention; and

FIG. 6 is an enlarged cross-sectioned view of a cavity shown in FIG. 2 with typical dimensional measurements for a device which has 33 electrodes per inch linear density. Higher densities are contemplated.

Referring to FIG. 1, a support substrate 10, which may be flat or planar as shown or bowed or curved if desired, has a first or bottom conductor array 11 formed thereon. Such conductor arrays may be gold, silver, copper. etc., as described in Baker, et al. US. Pat. No. 3,499,167 and are applied by any suitable conductor printing processes to thicknesses of from about 5,000 to about 10,000 angstrom units. It will be appreciated that such conductors may be small gauge wires which are placed in the desired pattern on the surface of plate 10 and adhered thereto by an adhesive until the later elements of the monolithic structure have been applied.

A dielectric layer or coating 12 is applied over the conductors 11 and has a thickness of from about 0.5 mil to about6 mils and in an operating example was about 1.2 mils thick. A variety of dielectric materials, especially lead borosilicates, are useful for this purpose and are known in the art.

Alternatively the dielectric layer or coating 12 may be applied as a thin film having a thickness of less than about 0.5 mil, typically ranging from about 0.1 to about 0.5 mil.

A top cooperating conductor array 13 is applied to the upper surface of the dielectric coating or layer 12 and can be applied in the same manner as the bottom conductor array 11 (it will be appreciated that the terms top and bottom are relative and could just as well be called row and column conductor arrays, respectively). Conductor array 13 is applied at transverse angles with respect to conductor array 11 to thereby define a plurality of matrix cross points.

A plurality of discrete discharge cavities 15 are formed in dielectric coating or layer 12. In the embodiment shown in FIG. 2 and FIG. 4, cavities 15 are located over the bottom conductors l1 and adjacent the top conductors 13. Each cavity may be formed by well known photoetching technique and/or chemical etching through a mask or screen having a pattern of holes in registry with the desired cavity location on the dielectric surface. Likewise, the use of a laser beam, sonic source of like energy is contemplated for drilling or forming the cavities. The cavities may comprise any suitable geometric shape such as a rounded hole, a groove, etc. In one such case, the mark had openings or apertures having a diameter of about 8 mils and the resulting cavities hadexemplary dimensions of about 12 mils diameter at the top and about 6 mils at the bottom with a dielectric layer thickness of about 1.2 mils. The etching process in this example was terminated so that a thin layer of about 0.1 to 0.2 mils of dielectric remained on the bottom conductor 11.

As shown in FIG. 3 the cavities need not be located over the bottom conductors or in alignment with any of the conductors but may, in their adjacency to the matrix cross points, only need to be positioned such that the electric field between the cross points is capable of manipulating the discharge condition of any gas in the cavities 15. Thus, the cavities may be located in any of the other sectors adjacent the matrix cross points such as indicated by dotted lines in the upper left corner of FIG. 3. In some cases, it may be desirable to place cavities 15 in all of these positions. It will also be appreciated that cavities 15 may be formed in dielectric layer 12 before or after the application of conductor array 13. It should also be noted that the cavities 15 may extend through the dielectric layer 12 into substrate layer 10. This configuration has the advantage that the size, and particularly the depth, of the cavity can be optimized independent of the thickness of dielectric layer 12.

The monolithic portion of the structure is completed by applying, as by vacuum integral techniques, an overcoat or layer 16 on the top conductor array 13 as well as in the cavities 15 and on the exposed surfaces of dielectric layer 12. The overcoat is typically nonconductive; however, the utilization of conductive overcoats is contemplated. As used herein, the term overcoat is intended to include any film, layer, deposit, etc., applied continuously or discontinuously to the dielectric or conducting surfaces.

The overcoat in addition to providing a coating on conductor array 13 is also preferably a good photoemitter and capable of lowering and stabilizing the operating voltage of the device.

In the practice of this invention, the overcoat typically comprises one or more layers of an oxide of lead, silicon, aluminum, titanium, zirconium, hafnium, magnesium, beryllium, calcium, strontium, or barium. Likewise, oxides of rare earths may be utilized, both of the Lanthanide and Actinide Series, especially scandium, yttrium, thorium, and cerium. For conductive overcoats, pure metals such as zinc, lead, gold, copper, silver, etc., may be used.

Thus, all of the electrically operative structural elements are monolithically formed as an integal assembly. In fact, the electrically operative elements may, if desired, be formed on substrate 10 in such a way as to be removable from the substrate after forming and mounting in a gas filled envelope. However, in one preferred embodiment hereof, a spacer-sealant member 18, such as any well known glass frit sealant is silk screened on the surface of the monolithic assembly, but short of the lateral edges of plate 10 so as to permit the conductors in the arrays to extend to the edges of the plate to permit connection to external circuits. A viewing cover plate 19, is mounted on the monolithic assembly in spaced relation by means of spacer sealant rib 18. It is preferred that the overcoat 16 be limited to the area of the panel where good photoemissivity is desired and not under spacer-sealant 18. The spacing between cover plate 19 and the monolithic assembly is not critical, and may form a gas reservoir or chamber for the assembly. In some embodiments the spacing is made small in order to further confine the discharge to the cavities 15. A gas filling tubulation, not shown, may

be applied to substrate 10 (outside the vieweing area of the device) or to viewing plate 19. I In the prior art, a wide variety of gases and gas mixtures have been utilized as the gaseous medium in a gas discharge device. Typical of such gases include C; C0 halogens; nitrogen; NH oxygen; water vapor; hydrogen; hydrocarbons; P 0 boron fluoride; acid fumes; TiCl H 0 vapors of sodium, mercury, thallium, cadmium, rubidium, and cesium; carbon disulfide; laughing gas; H 8; deoxygenated air; phosphorus ,vapors; C I-I CH naphthalene vapor; enthracene;

freon; ethyl alcohol; methylene bromide; heavy hydrogen; electron attaching gases; electron free gases; sulfur hexafluoride; tritium; radioactive gases; and especially the rare or inert gases.

In one highly preferred embodiment hereof, there is utilized two or more rare gases selected from neon, argon, xenon, krypton, and radon in the presence or absence of effective amounts of other gaseous components such as mercury and/or helium.

A modification in the monolithic structure and manner of forming the cavities is shown in FIG. 5. In this embodiment before applying dielectric layer 12, the bottom conductor array 11 has applied thereto barrier coating which is resistant to the etchant used to form the cavities. Thus, after the dielectric layer 12 has been applied, the etchant removes the dielectric 12 to barrier 20. This avoids any variation in the thickness of dielectric over bottom conductor 11 when the cavities are to be located thereover. Such a barrier 20 may be non-conductivematerial such as alumina, chrome nitride, etc., deposited by vacuum deposition techniques to a thickness of about 5,000 to about 10,000 angstrom units.

In the practice of this invention, it may also be feasible to obtain good panel performance without any cavities. In one such embodiment, a photoemissive overcoat may be employed exclusively over each discharge site or cell, so as to isolate the discharge cell from adjacent or other neighboring cells.

In a further embodiment and modification of this invention, the overcoatis omitted from the top electrode array such that the electrodes are in direct contact with the gaseous medium. In such embodiment, the discharge takes place between the top bare or exposed electrode and the bottom of the cavity.

In a further embodiment hereof, the top and/or bottom electrodes may be split with the cavity positioned in between or within the two halves of the split electrode. The two halves could also be electrically manipulated separately for purposes of addressing (such as with capacitively or gas discharge coupled multiplexing techniques).

In further embodiments of this invention, it is contemplated that other overcoat or barrier layers may be employed, especially luminescent phosphors. Likewise, phosphors may be positioned within the device as dots, bars, etc., so as to be excited by a gas discharge or other means.

Specific locations of the phosphor within the device may vary. In one specific embodiment, the phosphor is positioned within one or more cavities, e.g., at the bottom and/or on the walls ofa cavity. In another embodiment, the phosphor is positioned along the gas contacting surface of face plate 19, e.g., across from a cavity.

It is further contemplated in the practice hereof that two or more phosphors may be combined so as to produce a multicolor display, each phosphor being excited by the same or different source. In such embodiment, the radiation from one phosphor may be used to excite another phosphor.

As an extension of this embodiment it is possible to produce multicolor displays by-the use of two or more phosphors with a different color phosphor at adjacent electrode intersections. This allows control of the discharge so as to excite only the color desired. In this manner, one could produce red characters on a green background for a more striking visual display.

Another extension is the use of three color dots, as commonly used in cathode ray tubes, to obtain multicolor displays. To get true color pictures a means of controlling the intensity of the light from each color is necessary. Possible ways of doing this are varying the voltage applied to the discharge exciting a particular color; varying duration of discharge; use of multilayers of glass and phosphor; the use of multi-cells (variable intensity); and addressing the various phosphor layers independently.

In the practice of this invention, it is contemplated using any suitable luminescent phosphor. In the preferred embodiment, the phosphor is photoluminescent. The term photoluminescent phosphor includes quite generally all solid and liquid, inorganic and organic materials capable of converting an input of absorbed photons into an output of photons of different energy, the output comprising visible light of a brightness and intensity sufficient for visual display.

Typical photoluminescent phosphors contemplated include, not by way of limitation, both activated and non-activated compounds, e.g., the sulfides such as zinc sulfides, zinc-cadmium sulfides, zinc-sulfoselenides; the silicates such as zinc silicates, zincberyllo-silicate, Mg silicates; the tungstates such as calcium tungstates, magnesium tungstates; the phosphates, borates, and arsenates such as calcium phosphates, cadmium borates, zinc borates, magnesium arsenates; and the oxides and halides such as selfactivated zinc oxide, magnesium fluorides; magnesium flyorogermanate. Typical activators include, not by way of limitation, Mn, Eu, Ce, Pb, etc.

In one highly preferred embodiment, there is utilized a phosphor Pl as defined by JEDEC Electrode Tube Council, Publication No. 16A of January 1966, revised February I969. P1 is manganese activated zinc silicate (Zn SiO :Mn).

The phosphor particles may be applied to the dielectric alone or in combination with solvents, binders, or other convenient materials.

The phosphor may be applied to the dielectric by way of any convenient method including, not by way of limitation, vapor deposition; vacuum deposition; chemical vapor deposition; wet spraying or settling upon the dielectric a mixture or solution of the phosphor suspended or dissolved in a liquid, followed by evaporation of the liquid; silk screening; dry spraying of the phosphor upon the dielectric; electrom beam evaporation; plasma flame and/or are spraying and/or deposition; thermal evaporation; laser evaporation; Rf or induction heating evaporation; sputtering target techniques; and/or attachment of the phosphor to the dielectric as disclosed in the copending U.S. Pat. application Ser. No. 101,433, filed Dec. 24, 1970 by Robert N. Clark, and assigned to the assignee of the instant patent application.

In accordance with the broad practice of this invention, it is contemplated applying the phosphor to the dielectric (surface or sub-surface) in any suitable geometric shape, pattern, or configuration, symmetrical or asymmetrical as disclosed for example in the copending US. Patent application Ser. No. 98,846, filed Dec. 16, 1970 by Felix H. Brown and Robert F. Schaufele, and assigned to the assignee of the instant patent application.

The advantages of this invention over present panel structures include:

The discharges take place between the bottom or side wall of a depression, under or adjacent to which is a back or bottom conductor and the side wall and/or top of a top conductor covered with a thin film dielectric. The distance between these two points, once established, can be held thru heat treatments and sealing processes even if the entire plate is warped. Prior art construction must hold the distance between the front and back plate accurately, since the discharge occurs between the two plates.

Since the discharge takes place on a single side of a plate, as opposed to between two plates, the front plate 19 is free for other use. The most obvious use is to simply leave it clear for maximum use of light generated in the discharge. This is possible because there are no electrodes or films to block it. Another use is for the application of phosphors.

While the device remains basically an open structure geometry as in Baker, et al. US. Pat. No. 3,499,167, some optical isolation and electrical field focusing are obtained. Thus, it is possible to obtain some compromise between good conditioning and ultraviolet crosstalk on color applications.

Electrostatic field focusing is caused by the depression similar to the Bitzer, et al. sandwich structure. The fields should also be better focused around the front electrodes since they are covered only by a thin dielectric overcoat possibly leading to slightly higher densities.

A monolithic or one-sided plasma display panel has been known in the prior art as evidenced by U.S. Pat. No. 3,646,384 issued to Lay of IBM. However, in such devices, the discharge units or cells must be positioned at a relatively lower resolution, e.g., on the order of about three electrode lines per inch linear density, so as to prevent one discharge from interfering with another.

ln accordance with this invention such interference is significantly reduced, perhaps even eliminated for all practical purposes, by isolation of the discharges, e.g., through the use of cavities and/or photoemissive overcoats selectively applied to each discharge unit.

The practice of this invention makes possible the fabrication and construction of a high resolution device, e.g., at least 33 electrode lines per inch linear density--a resolution of at least 10 times that of the prior art monolithic devices. Of course, higher resolutions are possible and are contemplated.

I claim:

1. A monolithic gas discharge display/memory device which comprises:

a dielectric member having a selected thickness;

a cover plate member for maintaining an inert ionizable gaseous medium on one side of the dielectric member;

a first array of electrodes on the surface of the gas side of the dielectric member;

a second array of electrodes on the surface of the opposite non-gas side of the dielectric member, the electrodes in the arrays defining cooperating pairs of electrodes;

electrical circuit means for applying a potential to the electrodes to cause a gas discharge at each cooperating pair of electrodes;

and a plurality of structural formations in said one side of the dielectric member forming gas-filled cavities in the gas side of the dielectric member, one cavity forming structural formation juxtaposed adjacent to each cooperating pair of electrodes, respectively, so as to isolate each gas discharge relative to other gas discharges and increase the resolu' tion of the device.

2. The invention defined in claim 1 wherein at least one photoluminescent phosphor is deposited within at least one cavity.

3. The invention defined in claim 1 wherein at least one photoluminescent phosphor is deposited on the gas-contact side of the cover plate.

4. The invention defined in claim 1 wherein the dielectric member is a thin film having a thickness of less than about 0.5 mil.

5. The invention defined in claim 1 wherein the dielectric member is a thick film having a thickness of greater than about 0.5 mil.

6. The invention defined in claim 1 wherein there is a dielectric overcoat on the first array of electrodes such that the electrodes in the array are not in direct contact with the gas in the cavities.

7. The invention defined in claim 6 wherein the monolithic device is formed on a support substrate which forms one structural member in the device on the non-gas side of the dielectric member.

Claims (7)

1. A monolithic gas discharge display/memory device which comprises: a dielectric member having a selected thickness; a cover plate member for maintaining an inert ionizable gaseous medium on one side of the dielectric member; a first array of electrodes on the surface of the gas side of the dielectric member; a second array of electrodes on the surface of the opposite nongas side of the dielectric member, the electrodes in the arrays defining cooperating pairs of electrodes; electrical circuit means for applying a potential to the electrodes to cause a gas discharge at each cooperating pair of electrodes; and a plurality of structural formations in said one side of the dielectric member forming gas-filled cavities in the gas side of the dielectric member, one cavity forming structural formation juxtaposed adjacent to each cooperating pair of electrodes, respectively, so as to isolate each gas discharge relative to other gas discharges and increase the resolution of the device.

2. The invention defined in claim 1 wherein at least one photoluminescent phosphor is deposited within at least one cavity.

3. The invention defined in claim 1 wherein at least one photoluminescent phosphor is deposited on the gas-contact side of the cover plate.

4. The invention defined in claim 1 wherein the dielectric member is a thin film having a thickness of less than about 0.5 mil.

5. The invention defined in claim 1 wherein the dielectric member is a thick film having a thickness of greater than about 0.5 mil.

6. The invention defined in claim 1 wherein there is a dielectric overcoat on the first array of electrodes such that the electrodes in the array are not in direct contact with the gas in the cavities.

7. The invention defined in claim 6 wherein the monolithic device is formed on a support substrate which forms one structural member in the device on the non-gas side of the dielectric member.

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