US3814970A - Gas discharge display panels - Google Patents

Gas discharge display panels Download PDF

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Publication number
US3814970A
US3814970A US00350711A US35071173A US3814970A US 3814970 A US3814970 A US 3814970A US 00350711 A US00350711 A US 00350711A US 35071173 A US35071173 A US 35071173A US 3814970 A US3814970 A US 3814970A
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Prior art keywords
oxide
film
gas
slabs
deposited
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Expired - Lifetime
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US00350711A
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English (en)
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J Reboul
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Thales SA
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Thomson CSF SA
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J11/00—Gas-filled discharge tubes with alternating current induction of the discharge, e.g. alternating current plasma display panels [AC-PDP]; Gas-filled discharge tubes without any main electrode inside the vessel; Gas-filled discharge tubes with at least one main electrode outside the vessel

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  • ABSTRACT Gas discharge display panels presenting improved electrical characteristics due to the presence, upon the surfaces in Contact with the gas being ionised, of a metal oxide whose electronic configuration incorporates an unsaturated f electron-shell for example thorium oxide or gadolinium oxide.
  • the present invention relates to improvements in gas-discharge display panels and relates more particularly to an improvement in the structure of panels of this kind, by which it is possible to improve the electrical performance and the stability of operation over a period of time.
  • These panels comprise two slabs, of glass for example, which are relatively thick andtherefore rigid, between which there is enclosed the assembly of display cells that is to say the cells of ionisable gas, and the control electrodes.
  • control electrodes constituted by two networksof intercrossing conductive bands, are directly deposited upon the mutually opposite faces of the two slabs and covered with a film of transparent dielectric material, for example a vitrified mineral enamel.
  • the assembly is closed off by a sealing ring, bonded between the two slabs and around their peripheries, this ring delimiting the sealed enclosure into which the ionisable gas is introduced.
  • the gas cells can be physically delimited in relation to one another; in this case, an insulating matrix which is pierced by a rectangular network of holes is inserted into the enclosure between the two slabs; and the holes are of course opposite the points of intercrossing between the electrodes of the two crossed networks.
  • there is no matrix andthe display cells are not physically defined; they are delimited, on application of a voltage to the control electrodes, by the electric field configuration which results.
  • Such panels present two main drawbacks due to the nature of the dielectric material film which covers the electrodes. and is in contact with the gas to be ionised.
  • this dielectric material in order to have adequate melting properties and therefore be, able to be deposited during the manufacture of the panel, is generally made of an enamel containing a large proportion of lead oxide, sometimes cadmium or again zinc. Moreover, in order to be capable of vitrification it contains silica and several of the constituents of glass (alumina, boric anhydride).
  • This composition means that it has quite a high work function.
  • the striking voltage for providing the gas discharge in the display cells is consequently high too, this voltage varying in the same sense as the work function of the material at the surface of the dielectric film.
  • the result is that the control voltages applied to the electrodes must themselves be quite high and this is a first drawback of these panels.
  • the stability of the oxides utilised as flux in the enamel, particularly lead oxide, is not very good.
  • a gas-discharge display panel in accordance with the invention comprises two insulating slabs which are sealed along their peripheries, in order to form a sealed enclosure between their opposing faces, said enclosure being filed with an ionisable gas, and two crossed networks of orthogonal electrodes arranged onto the opposing faces of said slabs, said opposing faces being covered with a layer of material containing an oxide of a metal of the lanthanide or actinide families.
  • This film having an electronic configuration presenting an unsaturated f electron-shell has a work function which is relatively lower than that of an enamel and a presents higher stability in the face of ionbombardment; it may either be deposited upon the enamel covering the network of electrodes or deposited directly upon the electrode networks themselves.
  • FIG. 1 is a schematic sectional view of an improved display panel in accordance with the invention, without a matrix;
  • FIG. 2 is a view identical to that ofFlG. l, ofa panel with a matrix.
  • FIG. 1 illustrates, in section, part of a panel in accordance with the invention, without a matrix
  • FIG. 2 is equivalent view of a panel in accordance with the invention, with a matrix.
  • these panels comprise two thick slabs l and 2 of an insulating material, at least one of which is transparent (that through which the dis played data are observed).
  • the two slabs are generally made of glass.
  • each of these slabs there is deposited a network of parallel conductors 3 and 4 constituting control electrodes. These conductors are deposited in a conventional manner in order to form two crossed networks; the control voltages are applied to their exposed portions outside the enclosure containing the gas which constitutes the display surface proper.
  • the slabs and the electrodes are covered with a dielectric film 5, 6 formed by a film of vitrified enamelin accordance with the prior art technology.
  • these dielectric films 5 and 6 there are respectively deposited thin films 7 and 8 of a metal oxide, the electronic configuration of which comprises an unsaturated f electron-shell, that is to say a metal belonging to the lanthanide or actinide.
  • a metal oxide the electronic configuration of which comprises an unsaturated f electron-shell, that is to say a metal belonging to the lanthanide or actinide.
  • these oxides advantageously gadolinium oxide or thorium oxide will be chosen, these having very good thermal stability and having work functions in the order of 2 to 3 electronvolts that is to say much lower than the work functions of the enamel which is between 4 and 5 electron-volts.
  • a sealing ring 9 hermetically seals the two slabs at their periphery and thus closes off the enclosure 10 which is filled with an ionisable gas.
  • the seal is produced by means of an enamel, a cement, or any other suitable material.
  • the ionisable gas will for example be introduced into the enclosure 10, after sealing, through a hole (not shown) formed in one of the slabs and communicating with a pip (not shown) which enables pumping to be carried out, filling with gas and then sealing.
  • the panel has no matrix; the ionisation of the gas is limited substantially to a small cylinder (as indicated at 11 and 12 for two cells in FIG. 1), by the configuration of the electric fields created by the control voltages applied to the electrodes.
  • the matrix 13 of insulating material, containing a rectangular network of cylindrical holes 14, defines said cells.
  • the metal oxide constituted in films 7 and 8 (thorium oxide will be referred to in the following although the invention is in no way limited to this oxide alone, as mentioned hereinbefore) is deposited solely upon the display surface proprer where the gas discharges are produced; the presence of this oxide on the part serving to bond the two slabs together, could introduce unwanted mechanical stresses.
  • Thorium oxide is deposited for example by the conventional process of vaporisation under vacuum, using electron bombardment.
  • the film thickness should be sufficient to resist ion bombardment throughout the service life of the panel. It is therefore made more than a few hundred A units in thickness.
  • the thorium oxide film can, of course, be deposited solely on the surfaces corresponding to the discharge zones, that is to say at the locations corresponding to the holes 14 in the matrix.
  • the thorium oxide film is deposited directly upon the slabs and itself covers the network of electrodes.
  • the thorium oxide film then has to be thicker and since its deposition by vaporisation takes longer, the solution is a more expensive one than the others mentioned before. However, it is one which can be considered.
  • thode-sputtering Although one possible method ofdepositing thorium, as mentioned before, is vaporisation under vacuum by electron bombardment, a conventional method of depositing thin transparent films of high uniformity and high quality, other methods are possible such for example as cathode-sputtering.
  • thorium oxide films can, without any drawback, contain quite a high proportion of metallic thorium or one of the other known refractory oxides.
  • a gas discharge display panel comprising two insulating slabs which are sealed along their peripheries, in order to form a sealed enclosure between their opposing faces, said enclosure being filled with ionisable gas, and two crossed networks of orthogonal electrodes arranged onto the opposing faces of said slabs, said opposing faces being covered with a layer of material containing an oxide ofa metal of the lanthanide or actinide families.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Gas-Filled Discharge Tubes (AREA)
US00350711A 1972-04-19 1973-04-13 Gas discharge display panels Expired - Lifetime US3814970A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR727213828A FR2180522B1 (enrdf_load_stackoverflow) 1972-04-19 1972-04-19

Publications (1)

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US3814970A true US3814970A (en) 1974-06-04

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US00350711A Expired - Lifetime US3814970A (en) 1972-04-19 1973-04-13 Gas discharge display panels

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US (1) US3814970A (enrdf_load_stackoverflow)
JP (1) JPS4921059A (enrdf_load_stackoverflow)
DE (1) DE2319754A1 (enrdf_load_stackoverflow)
FR (1) FR2180522B1 (enrdf_load_stackoverflow)
GB (1) GB1415779A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4126809A (en) * 1975-03-10 1978-11-21 Owens-Illinois, Inc. Gas discharge display panel with lanthanide or actinide family oxide
US5793158A (en) * 1992-08-21 1998-08-11 Wedding, Sr.; Donald K. Gas discharge (plasma) displays

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4027195A (en) * 1974-08-23 1977-05-31 Nippon Electric Company Ltd. Voltage switching device comprising a gas discharge panel
JPS628119Y2 (enrdf_load_stackoverflow) * 1977-12-14 1987-02-25
JPS5516346A (en) * 1978-07-19 1980-02-05 Nec Corp Gas discharge indicator

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3634719A (en) * 1970-09-08 1972-01-11 Owens Illinois Inc Gas discharge display/memory panel having lead oxide coated dielectric plates with decreased aging time

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3634719A (en) * 1970-09-08 1972-01-11 Owens Illinois Inc Gas discharge display/memory panel having lead oxide coated dielectric plates with decreased aging time

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4126809A (en) * 1975-03-10 1978-11-21 Owens-Illinois, Inc. Gas discharge display panel with lanthanide or actinide family oxide
US5793158A (en) * 1992-08-21 1998-08-11 Wedding, Sr.; Donald K. Gas discharge (plasma) displays

Also Published As

Publication number Publication date
FR2180522B1 (enrdf_load_stackoverflow) 1974-07-26
GB1415779A (en) 1975-11-26
FR2180522A1 (enrdf_load_stackoverflow) 1973-11-30
DE2319754A1 (de) 1973-10-31
JPS4921059A (enrdf_load_stackoverflow) 1974-02-25

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