US3764847A - Glow-discharge display device - Google Patents

Glow-discharge display device Download PDF

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Publication number
US3764847A
US3764847A US00267141A US3764847DA US3764847A US 3764847 A US3764847 A US 3764847A US 00267141 A US00267141 A US 00267141A US 3764847D A US3764847D A US 3764847DA US 3764847 A US3764847 A US 3764847A
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electrically resistive
anode
electrically
display device
film
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US00267141A
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English (en)
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J Smith
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US Philips Corp
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US Philips Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H01J17/38—Cold-cathode tubes
    • H01J17/48—Cold-cathode tubes with more than one cathode or anode, e.g. sequence-discharge tube, counting tube, dekatron
    • H01J17/49—Display panels, e.g. with crossed electrodes, e.g. making use of direct current

Definitions

  • the invention relates to an electrical glow-discharge display device comprising an array of anode-cathode electrode pairs defining an array of individually addressable glow-discharge paths through a gas atmosphere contained in said device,-and a cross-bar addressing system therefore, the anodes of each row of the array being individually connected through an electrically resistive connection to a common row supply conductor which forms part of the addressing system.
  • Such a device may be used for displaying simple patterns such as diagrams, numerals, words or the like. Energisation of the individual discharge paths in such devices may be accomplished by supplying each one separately from an external circuit.
  • the device may include a common anode for all the elements and individual connections to each cathode. While this is feasible'for small total members of elements e.g., a 7 X array, for larger arrays the required number of individual connections to the device rapidly becomes impracticably large and it becomes necessary to use an alternative form of addressing each element, such as a cross-bar addressing system in which an element is energised only during the period in which the row and column containing that element are energised.
  • the cathodes are connected together in linear groups, say in columns, and the anodes are connected together in a linear groups orthogonal to these, say in rows.
  • the terms row and column are used herein namely in a comparative sense; in practice the array may be orientated so that the rows extend from top to bottom and the columns extend from side to side.
  • a current limiting resistor is connected in series with each anode row or each cathode column in order to limit the current through the discharges. As each current limiting resistor can control only one discharge at any time the resistor must be time-shared between all the discharges on its row or column.
  • An electrical glow-discharge display device is known (see U.S. Pat. 3,612,938) with an electrically resistive layer consisting of a phosphorus vanadate glass on the anode conductors of a cross-bar addressing system in a glow-discharge display tube.
  • an electrically resistive layer consisting of a phosphorus vanadate glass on the anode conductors of a cross-bar addressing system in a glow-discharge display tube.
  • An electrical glow-discharge display device of the type mentioned in the preamble is, according to the invention, characterized in that the anodes, the electrically resistive connections and the row supply conductors are formed by thin films deposited on an inner surface of an optically permeable viewing window of the device, and that at least the major portion of the electrically resistive connections and of the row supply conductors are covered with an electrically insulating layer.
  • Thin-film is to be understood herein to mean an electrically conductive or semiconductive film which has been deposited in a vacuum or a reduced-pressure atmosphere.
  • the insulating layer is preferably substantially continuous over substantially the whole of said inner surface with the exception of breaks at each anode film.
  • an individual electrically conductive layer is deposited over the insulating layer which covers each electrically resistive thin-film connection, and that said conductive layer electrically contacts the cor responding anode film.
  • each said electrically resistive connection comprises a meandering path of a film of an electrically resistive material.
  • Said electrically resistive material is preferably nichrome and said anodes and said row supply conductors are preferably formed by a nichrome film which is thicker than the film forming said electrically resistive connections.
  • cathodes and column supply conductors therefore comprise elongate electrical conductors which extend through a block of electrically insulating material so that each elongate conductor is exposed at the base of each cavity of a column of cavities in a major surface of said block, the
  • Each cavity preferably tapers from its open end to its base.
  • FIG. 1 is a plan view of part of a glow-discharge display tube
  • FIG. 2 is a perspective view of a transverse section of the part of FIG. 1 together with a viewing window, and
  • FIG. 3 is a plan view of the inner surface of part of the viewing window.
  • FIG. 1 a block 1 of electrically insulating material, has been moulded around a set of conducting cathode strips 2 which form one electrode set of a cross-bar addressing system and which are led through the sides of the block I in a vacuum-tight manner.
  • the top face of the block 1 is provided with an array of cavities 3 which extend downwards as far as the strips 2. Thus part of a strip 2 is exposed in each cavity.
  • the top face of the block 1 is provided with two sets of parallel ridges 4 which extend in the length and width directions of the block I so as to separate the individual cavities 3 from each other.
  • FIG. 2 is a perspective view of a cross-section taken on the line Il-II of FIG. 1.
  • a transparent viewing window plate 9 is sealed at 16 in a vacuum-tight manner to the top of a ridge provided round the periphery of the top of the block 1.
  • the ridge is slightly higher than the ridges 4 so that a small gap of e.g., 25 m is present between the tops of the ridges 4 and the inner surface of the window plate 9 in order to allow the completed tube to be pumped and gas-filled in a uniform manner
  • the window plate 9 may be made of glass available under the type number 7059 Coming.
  • the block 1 may be made of the material available under the Registered Trade mark Fusite H, a glass having an expansion coefficient suitably matched to nickel-iron if such material is used for the strips 2.
  • ridges 4 shown in FIG. 2 may be omitted.
  • FIG. 3 is a plan view of the inner surface of part'of the viewing window 9.
  • an array of anode electrodes 10 of gold or nichrome.
  • the array of anode electrodes corresponds to the array of cathode cavities 3.
  • the anodes of each row of the array are each connected to a cross-bar supply conductor 11 therefore (which are also gold or nichrome) via an individual series resistor formed'as a meandering thin-film path 12 of electrically resistive material which may again be nichrome and which is deposited on the surface of the window 9.
  • a supply wire or strip 14 is bonded to the termination of each anode supply conductor 11, which conductor may, if it is of nichrome, be gold plated during manufacture either completely or at its terminations only.
  • the whole surface of the window 9 with its deposited layers is covered with a layer of electrically insulating material (not shown) such as evaporated silicon monoxide or R.F.- sputtered silicon dioxide except at the areas of the anodes l0 and the anode supply conductor terminations 13.
  • an individual transparent electrically conductive layer such as nichrome may then be deposited on this insulating layer over part or the whole of each resistor 12 so as to contact the corresponding anode l0 and effectively increase the area thereof.
  • the anodes l0 and supply conductors ll be of low resistance.
  • the conductive layers 11 may be several thousand A thick while the layers forming the electrodes 10 and the resistive paths 12 may be several hundred A thick.
  • They may be made by coating the whole surface of the plate 9 by a layer of nichrome several thousand A thick, coating the terminations 13 with gold, etching these coatings by a photolithographic technique to leave the nichrome only at the locations of the anodes 10 and conductors 11, and nichrome/gold at terminations 13, coating the complete surface of the plate with a layer of nichrome hundred A thick, and etching this coating by a photolithographic technique to leave this nichrome only at the locations of the electrodes 10, the paths l2 and the conductors 11.
  • the whole surface of the plate 9 with its nichrome layers may be coated with silicon monoxide or silicon dioxide about lp.m thick except at the extremities of the terminations l3 (i.e., up to a boundary 15), this silicon monoxide or dioxide then being etched only at the areas of the electrodes 10 by a photo-lithographic technique to expose these electrodes.
  • the aforementioned individual conductive layers may then be deposited over each anode 10 and resistor 12.
  • the resistive paths 12 are of nichrome several hundred A thick they may each be 40 mm long and have a width of 20am giving a resistance of each path of between 2 X 10 and 2 X 10 ohme depending on how the layers are deposited and the subsequently heating schedules used in assembling the panel.
  • the electrodes 10 may each be in the form of a square of 0.3 mm side for an overall discharge cell size of 1.5 mm square, or of 0.1 mm side for an overall cell size of 1.0 mm square.
  • the cavities 3 were disposed in a rectangular array of the form shown in FIG. 2 but without the ridges 4.
  • Each cavity was 0.8 mm square at its top tapering to 0.4 mm square at its base and the spacing between the cathode at the base of each cavity and the window plate 9 was 0.625 mm.
  • the cavity depth was 0.6 mm.
  • the cavities were 1.0 mm between centres (as were the anode electrodes 10 in order to correspond therewith).
  • the completed tube was then aged by applying an operating potential between each cathode and anode supply conductor and continuing this application for several hours.
  • a positive potential of, e.g., 250V was applied to the supply wires or strips 14 relative to the cathode strips 2, this potential being above the maximum maintaining potential of glow-discharges in the cavities 3 (which may be e.g., 220V) but below the minimum striking potential thereof.
  • An additional positive pulseof, e.g., 150V was then applied to each wire or strip 14 in'turn, the length of these pulses being sufficient to ensure that each anode-cathode discharge path in the corresponding row ignited.
  • each pulse length may be approximately l50p,sec.
  • the potential at the corresponding conductor 14 was reduced to, e.g., 30V below its original potential for, e.g., l50p.sec. simultaneously with the application of positive-going pulses of, e.g., 30V to those cathode conductors 2 corresponding to the cross-points with the relevant conductor 14 where a discharge was not desired.
  • the potential at these cross-points was reduced momentarily to 190V (below their maintaining potential) and the corresponding discharges extinguished to leave only those desired. This was repeated for the remainder of the rows to build up the desired display.
  • nichrome electrodes quoted are semitransparent and any glow discharge can be observed through them. Of course, even if the electrodes 10 were opaque, it would still be possible to observe the discharge through the gaps between adjacent turns of the resistive paths 12.
  • Electrical glow-discharge display device comprising an array of anode-cathode electrode pairs defining an array of individually addressable glow-discharge paths through a gas atmosphere contained in said device, and a cross-bar addressing system therefore, the anodes of each row of the array being individually connected through an electrically resistive connection to a common row supply conductor which forms part of the addressing system, the anodes, the electrically resistive connections and the row supply conductors being formed by thin films deposited on an inner surface of an optically permeable viewing window of the device,
  • Display device as claimed in claim 2 wherein an individual electrically conductive layer is deposited over the insulating layer which covers each electrically resistive thin-film connection, and said conductive layer electrically contacts the corresponding anode film.
  • each said electrically resistive connection comprises a meandering path of a film of an electrically resistive material.
  • said electrically resistive material is nichrome and said anodes and said row supply conductors are a nichrome film which is thicker than the film forming said electrically resistive connections.
  • the cathodes and column supply conductors therefore comprise elongate electrical conductors which extend through a block of electrically insulating material so that each elongate conductor is exposed at the base of each cavity of a column of cavities in a major surface of said block, the inner surface of said viewing window facing said major surface with the anode films aligned with the open ends of the cavities and spaced therefrom.
  • each cavity tapers from its open end to Its base.

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US00267141A 1971-07-22 1972-06-28 Glow-discharge display device Expired - Lifetime US3764847A (en)

Applications Claiming Priority (1)

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GB3436971 1971-07-22

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US3764847A true US3764847A (en) 1973-10-09

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US (1) US3764847A (enExample)
CA (1) CA954179A (enExample)
DE (1) DE2234199A1 (enExample)
FR (1) FR2146480B1 (enExample)
GB (1) GB1325260A (enExample)
NL (1) NL7209538A (enExample)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3849688A (en) * 1973-06-28 1974-11-19 Burroughs Corp Display panel having rows and columns of cells with wide viewing angle
US3876906A (en) * 1972-06-21 1975-04-08 Ferranti Ltd Visual display devices
US3889150A (en) * 1974-07-30 1975-06-10 Burroughs Corp Gaseous discharge display panel with scanning anode base plate assembly including resistive masses
US3908147A (en) * 1973-09-28 1975-09-23 Philips Corp Glow-discharge display device including cathode elements of finely divided carbon

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3334269A (en) * 1964-07-28 1967-08-01 Itt Character display panel having a plurality of glow discharge cavities including resistive ballast means exposed to the glow discharge therein

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3334269A (en) * 1964-07-28 1967-08-01 Itt Character display panel having a plurality of glow discharge cavities including resistive ballast means exposed to the glow discharge therein

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3876906A (en) * 1972-06-21 1975-04-08 Ferranti Ltd Visual display devices
US3849688A (en) * 1973-06-28 1974-11-19 Burroughs Corp Display panel having rows and columns of cells with wide viewing angle
US3908147A (en) * 1973-09-28 1975-09-23 Philips Corp Glow-discharge display device including cathode elements of finely divided carbon
US3889150A (en) * 1974-07-30 1975-06-10 Burroughs Corp Gaseous discharge display panel with scanning anode base plate assembly including resistive masses

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Publication number Publication date
FR2146480A1 (enExample) 1973-03-02
GB1325260A (en) 1973-08-01
FR2146480B1 (enExample) 1977-07-22
NL7209538A (enExample) 1973-01-24
DE2234199A1 (de) 1973-02-01
CA954179A (en) 1974-09-03

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