US3579015A - Electron beam addressed plasma display panel - Google Patents

Electron beam addressed plasma display panel Download PDF

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Publication number
US3579015A
US3579015A US808195A US3579015DA US3579015A US 3579015 A US3579015 A US 3579015A US 808195 A US808195 A US 808195A US 3579015D A US3579015D A US 3579015DA US 3579015 A US3579015 A US 3579015A
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gas
cells
electron beam
discharge
filled
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US808195A
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English (en)
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Robert O Gregory
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Monsanto Co
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Monsanto Co
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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
    • H01J17/492—Display panels, e.g. with crossed electrodes, e.g. making use of direct current with crossed electrodes

Definitions

  • the present invention relates generally to an information storage and/or display tube of the plasma or gas discharge type, and more particularly, to a storage tube having lightemitting elements which may be turned on and off by means of an electron beam.
  • plasma display panels be employed to take advantage of their inherent memory; i.e. bistable mode of operation, long life and high brightness. See for example, proceedings, Fall Joint Computer Conference The Plasma Display-A Digitally Addressable Display With Inherent memory, by D. L. Bitzer and H. G. Slottow, Nov. i966, p. 541,
  • Such plasma display panels generally comprise three laminated sheets of flat glass plates. The center glass laminate being provided with an array of small gas-filled apertures, referred to as bistable plasma display cells.
  • a visual gas discharge may be achieved by proper selection of the gas mixture and the application of a voltage signal of an appropriate value to selected cells.
  • each cell can be made independent of all other cells and is bistable in nature. That is, a sustaining AC voltage having a value less than the critical firing voltage may be applied across all cells, and although it is sufficient to sustain half-cycle discharges once initiated, it effects no discharge until it is combined with an actuation voltage to render the total cell voltage greater than the critical firing voltage. Once the half-cycle discharge is initiated, the information signal may be removed, yet the cell will continue to emit light under the influence of the sustaining field. Thus, bistable operation is achieved.
  • the outer laminates of plasma display panels of the type just described have been provided with a crossed-grid arrangement of electrical conductive strips for the purpose of applying the "sustaining and actuation voltages to the cells selected for discharge operation.
  • Application of an actuation voltage pulse to two crossed-grid conductors results in the energization or discharge of the gas-filled cell provided at the intersection of the two conductive strips,
  • the crossed-grid conductor arrangement for addressing the light-emitting cells of plasma display panels has been employed satisfactorily in certain applications.
  • the deposition of conductive strips is a time-consuming and an expensive step in the manufacture of panel displays embodying a large number of cells for high resolution.
  • elaborate switching circuitry capable of handling voltages of several hundred volts is required to properly select the proper conductive strips required to store or display the information.
  • the general purpose of this invention is to provide a storage tube of the plasma display type, which embraces all of the ad vantages of similar plasma display panels yet does not possess the aforedescribed disadvantages.
  • the present invention utilizes an electron beam addressing arrangement for energizing and deenergizing selected plasma display cells.
  • An object of the present invention is the provision of a plasma-display-type direct view storage tube, the manufacture of which is susceptible to relatively simple production techniques.
  • Another object of the present invention is the provision of a direct view storage tube, wherein information can be selec tively stored or erased at electron beam scanning speeds.
  • a storage tube having substantially flat insulating members separated by a plurality of plasma discharge cells.
  • the cells are filled with an ionizable gas or gas mixture and electrodes are secured to the outer surfaces of the insulating members.
  • One of the electrodes is continuous and transparent, while the other is a thin conductive metal layer having apertures arranged over gasfilled cells.
  • An AC power supply is connected between the two electrodes to provide a sustaining potential.
  • An electron beam addressing system is employed to direct an electron beam through the apertures of the metal electrode to energize and deenergize selected cells.
  • FIG. 1 is a perspective view of a storage tube constructed in accordance with the present invention
  • FIG. 2 is an enlarged broken-away, cross-sectional view of a display panel portion of the storage tube of FIG. 1;
  • FIG. 3 is an enlarged, detailed view revealing a portion of one of the electrodes deposited on the display panel portion of FIG. 2;
  • FIG. 4 is a schematic view of the electron beam addressing system and circuit connections of the storage tube of FIG. 1;
  • FIG. 5 is a schematic representation of wall charge accumulation during a portion of the operation of the storage tube of FIG. l;'and
  • FIG. 6 is a graphical representation of waveforms corresponding to the wall charges and applied voltages when the cell in in the on state, employed to store and display information by means of the storage tube of FIG. 1.
  • FIG. 1 a storage tube, designated 10.
  • the storage tube 10 consists generally of a gas discharge or plasma display panel 12 having a viewing surface 14, an evacuated glass envelope 16 sealed to and extending from the panel 12, and an electron beam addressing system 18.
  • the evacuated glass envelope 16 is sealed to the plasma display panel 12 and encloses the electron panel addressing system 18. It may be constructed in accordance with wellknown cathode ray tube fabrication techniques.
  • the plasma display panel of the present invention consists of three fiat sheets of insulating material, such as glass.
  • a center sheet 20 is sandwiched between two outer laminates 22 and 24, and has a plurality of apertures or cells 26 formed through it, by drilling, etching or other means.
  • the density of the cells 26 determines, in part, the resolution of the panel 12.
  • I have used glass sheets 0.006 inch in thickness with a distance between adjacent cells of 0.025 inch, thereby providing a cell density of approximately 1,600 cells per square inch.
  • the cells 26 are charged with a suitable gas or gas mixture; for example, a mixture of percent neon and 5 percent nitrogen at a pressure of 300 Torr has been found to provide an extremely fast, bright discharge.
  • a suitable gas or gas mixture for example, a mixture of percent neon and 5 percent nitrogen at a pressure of 300 Torr has been found to provide an extremely fast, bright discharge.
  • the outer surface of the glass sheet 22 is covered by a continuous, transparent electrode 28 such as stannous oxide, SnO while the outer surface of the outer laminant 24 is provided with a conductive-metal electrode 30, such as an aluminum film layer.
  • the electrode 30 is provided with apertures or openings 32 arranged in registration with the gas-filled cells 26, as may best be seen in FIG. 3.
  • the electron gun structure 34 consists of a suitably grounded cathode electrode 36, heated by a filament 38.
  • An accelerating potential represented by a battery 40 is connected between the cathode 36 of the electron gun and the electrode 30 of the gas discharge panel 12.
  • the apertured electrode, 30, may be operated at ground potential with the cathode at a high negative potential.
  • the electron gun structure 34 may be an electron gun commercially available from Superior Electronics Company and referred to as a SAQP electron gun, and the accelerating potential may be 6.5 kv.
  • the beam-gating input terminals 48 may be connected to an appropriate input signal source synchronized with the external deflection circuitry in accordance with well-known techniques. Thus, it is possible to modulate the intensity of the electron beam emanating from the electron gun assembly 34 during the scanning or sweeping of the beam across the display panel 12.
  • an AC voltage source 50 is connected between the electrodes 28 and 30 of the gas discharge panel 12.
  • the AC signal source 50 may be chosen to provide to the electrodes 28 and 30 a 500 volt peak sustaining voltage at a frequency of 300 kHz.
  • the AC voltage source 50 is applied to the electrodes 28 and 30 of the plasma display panel 12 to provide the necessary sustaining potential.
  • the sustaining voltage is insufficient to develop the critical firing voltage V, required to initiate plasma discharge of the gas within the cells 26.
  • Information can be written" on or stored within the storage tube 10 by applying an input signal to the beam-gating input terminal 48 so that the beam-gating grid 46 allows electrons to be accelerated from the electron gun cathode 36. These electrons are then deflected by the horizontal and vertical deflection plates 42 and 44; the amount of horizontal and vertical deflection corresponding to deflection potentials applied thereto.
  • the deflection signals may be synchronized with the application of the input signal in any well-known fashion so that selected cells are properly energized.
  • the deflection plates direct the accelerated electrons to the selected aperture of the aluminum electrode 30, where they accumulate on the surface of the glass sheet laminate 24.
  • This electron accumulation results in an electrical charge, and therefore electrical field, across the gas-filled cells arranged in registration with the aperture to which the electrons have been directed.
  • the electrical field so established will aid the field resulting from the sustaining voltage during one-half cycle.
  • the initial potential across the gas-filled cells is insufficient to produce plasma discharge, the additional potential provided by the accumulation of electrons at the aperture surface of glass sheet 24 will trigger the selected cell to its on state. Subsequently, the electron beam may be turned off by the beam-gating grid 46 of the electron beam structure 34, yet the energized cell will remain in its on state.
  • the electron beam can then be repositioned by means of the horizontal and vertical deflection plates 42 and 44 to energize another gas-filled cell in a like manner.
  • the sustaining voltage provided by the AC voltage source 50 serves to maintain the plasma discharge of those cells which are triggered on by means of the electron beam, even after the electron beam has been turned off or removed.
  • the plasma display panel 12 may be stored indefinitely.
  • the plasma discharge provides a bright visual display of the information.
  • the AC voltage source 50 may be turned off, thereby reducing the potential across the actuated cells to a level insufficient to maintain the plasma discharge.
  • the storage characteristic of a plasma display panel arises from the wall charge generated in each cell 26 as free charges during the gas discharge. These wall charges tend to migrate to the cell walls under the influence of the sustaining AC potential, and therefore arrange themselves so as to aid or add to the applied AC field at the beginning of each half-cycle of the applied AC sustaining voltage. These wall charges are represented in FIG. 5 for a single gas-filled, energized cell. Waveform representation of the applied AC sustaining voltage is shown in FIG. 6a, while a similar representation of the wall charge potential is shown in FIG. 6b.
  • time I the combined electrical field resulting from the wall charge and that of the AC sustaining voltage signal is sufficient to fire or discharge the cell.
  • the discharge of the cell reverses its wall charge polarity very rapidly so that the next half-cycle of operation repeats the discharge'phenomenon.
  • the electron beam may be pulsed to erase or deenergize a cell which is in its on state.
  • the pulsed electron beam deposits a charge on the dielectric surface upon which it impinges after passing through a selected aperture of the aluminum electrode 30.
  • the deposited charge opposes the electric field of the wall charge during the time period between time t and time t,. Therefore, if the deposited charge is sufficiently large and if it is applied between time t and 1,, the total electrical field across the cell will be insufficient to sustain the discharge which would otherwise occur at time 1,, resulting in the cell reverting to its off condition during the next half-cycle of the AC sustaining voltage signal.
  • the storage tube of the present invention employs a unique electron beam addressing system directly applied to the dielectric surface material of a plasma-displaytype panel in registration with cells to be triggered on or off.
  • a storage tube may be advantageously used as a storage oscilloscope where it is important that there by no loss of resolution of a displayed signal trace with the passage of time.
  • Another application of my storage tube would be that of a data display or storage memory; for example, in computer time-sharing scientific and educational applications. In these latter applications the resolution, indefinite storage time and selective erasure, present advantages not available with other types of data display system.
  • a storage tube Comprising a plurality of substantially flat insulating members defining storage cells therebetween,
  • electron beam addressing means positioned to direct an electron beam through selective apertures of said one electrode and onto the surface of one of said insulating 'members
  • a storage tube as defined in claim 1, wherein the other of said electrodes is a continuous transparent material.
  • a DC potential source connected between said gun and said one electrode to accelerate electrons emitted by said gun
  • deflection plates positioned between said electron gun and said one electrode for directing electrons emitted by said gun to selected apertures provided in said one electrode
  • an electron beam-gating grid positioned between said deflection means and said electron gun for gating the emission of electrons from said gun in response to electrical signals applied to said grid.
  • a combination display and storage tube comprising an evacuated envelope housing an electron gun, deflection plates, and an electron beam-gating grid,
  • a face plate including a panellikestructure of an insulating material and having a plurality of gas-filled cavities formed therein, the gas-filled cavities being charged with an ionizable gas
  • a pair of electrodes external to and separated from said gas filled cells by said insulating material, one of said electrodes defining apertures registered with said gas-filled cells, the other electrode being a continuous transparent electrode,
  • an AC power supply means connected between said electrodes for providing a sustaining potential less than that required to initiate discharge of said gas-filled cells, but sufficient to sustain such discharge once initiated
  • a method of addressing a storage tube of the type having a plasma display panel comprising a plurality of gas-filled, light-emitting cells formed within an insulating material comprising the steps of I applying to said gas-filled cells by means of electrodes external thereto an AC voltage signal having a magnitude insufficient to initiate discharge of the gas therein, but sufficient to sustain the light-emitting discharge once initiated, and
  • the metho o returning individual gas-fille cells formed within insulating material of a plasma display storage panel to their initial nonlight-emitting states comprising the steps of directing an electron beam to the surface of said insulating material in registration with cells to be returned to their off state, and pulsing an electron beam during an appropriate half-cycle time interval to deposit a charge on said surface in op- 7 position to wall charges developed within said cells.

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US808195A 1969-03-18 1969-03-18 Electron beam addressed plasma display panel Expired - Lifetime US3579015A (en)

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US80819569A 1969-03-18 1969-03-18

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US (1) US3579015A (de)
CA (1) CA934030A (de)
DE (1) DE2012664A1 (de)
FR (1) FR2035038A1 (de)
GB (1) GB1309591A (de)
NL (1) NL7003749A (de)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3753041A (en) * 1970-11-18 1973-08-14 Sperry Rand Corp Digitally addressable gas discharge display apparatus
US3766428A (en) * 1972-07-24 1973-10-16 Westinghouse Electric Corp High resolution, high intensity cathode ray tube
US3770960A (en) * 1972-06-26 1973-11-06 Gen Electric X-ray display panel
US3774063A (en) * 1971-09-27 1973-11-20 Columbia Broadcasting Syst Inc Selective excitation of a gaseous region
US3800186A (en) * 1972-02-16 1974-03-26 Hitachi Ltd Display device
US3800296A (en) * 1972-04-26 1974-03-26 Univ Illinois Optical write-in method and apparatus for a plasma display panel
US3801864A (en) * 1972-02-25 1974-04-02 Hitachi Ltd Display device
US4001635A (en) * 1974-06-14 1977-01-04 Thomson-Csf Electro-optical converter and an optical information recording system comprising such a converter
US4206460A (en) * 1977-03-10 1980-06-03 Sharp Kabushiki Kaisha EL Display drive controlled by an electron beam
US5019750A (en) * 1990-01-16 1991-05-28 Gte Products Corporation Radio-frequency driven display
US5691608A (en) * 1986-06-16 1997-11-25 Canon Kabushiki Kaisha Image display apparatus
US6822644B1 (en) * 1999-06-30 2004-11-23 Fujitsu Limited Method and circuit for driving capacitive load

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2500929A (en) * 1946-07-12 1950-03-21 Chilowsky Constantin Means for reproducing television images
US2972707A (en) * 1954-10-18 1961-02-21 Electro Voice Image reproducing device
US3262010A (en) * 1960-08-31 1966-07-19 Hughes Aircraft Co Electrical display apparatus incorpolrating electroluminescent and gas discharge devices
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
US3499167A (en) * 1967-11-24 1970-03-03 Owens Illinois Inc Gas discharge display memory device and method of operating
US3509421A (en) * 1967-09-11 1970-04-28 Burroughs Corp Plasma gas-filled display device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2500929A (en) * 1946-07-12 1950-03-21 Chilowsky Constantin Means for reproducing television images
US2972707A (en) * 1954-10-18 1961-02-21 Electro Voice Image reproducing device
US3262010A (en) * 1960-08-31 1966-07-19 Hughes Aircraft Co Electrical display apparatus incorpolrating electroluminescent and gas discharge devices
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
US3509421A (en) * 1967-09-11 1970-04-28 Burroughs Corp Plasma gas-filled display device
US3499167A (en) * 1967-11-24 1970-03-03 Owens Illinois Inc Gas discharge display memory device and method of operating

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3753041A (en) * 1970-11-18 1973-08-14 Sperry Rand Corp Digitally addressable gas discharge display apparatus
US3774063A (en) * 1971-09-27 1973-11-20 Columbia Broadcasting Syst Inc Selective excitation of a gaseous region
US3800186A (en) * 1972-02-16 1974-03-26 Hitachi Ltd Display device
US3801864A (en) * 1972-02-25 1974-04-02 Hitachi Ltd Display device
US3800296A (en) * 1972-04-26 1974-03-26 Univ Illinois Optical write-in method and apparatus for a plasma display panel
US3770960A (en) * 1972-06-26 1973-11-06 Gen Electric X-ray display panel
US3766428A (en) * 1972-07-24 1973-10-16 Westinghouse Electric Corp High resolution, high intensity cathode ray tube
US4001635A (en) * 1974-06-14 1977-01-04 Thomson-Csf Electro-optical converter and an optical information recording system comprising such a converter
US4206460A (en) * 1977-03-10 1980-06-03 Sharp Kabushiki Kaisha EL Display drive controlled by an electron beam
US5691608A (en) * 1986-06-16 1997-11-25 Canon Kabushiki Kaisha Image display apparatus
US5019750A (en) * 1990-01-16 1991-05-28 Gte Products Corporation Radio-frequency driven display
US6822644B1 (en) * 1999-06-30 2004-11-23 Fujitsu Limited Method and circuit for driving capacitive load

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FR2035038A1 (de) 1970-12-18
GB1309591A (en) 1973-03-14
DE2012664A1 (de) 1970-09-24
NL7003749A (de) 1970-09-22
CA934030A (en) 1973-09-18

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