US3242378A - Discharge indicator tube - Google Patents

Discharge indicator tube Download PDF

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Publication number
US3242378A
US3242378A US201967A US20196762A US3242378A US 3242378 A US3242378 A US 3242378A US 201967 A US201967 A US 201967A US 20196762 A US20196762 A US 20196762A US 3242378 A US3242378 A US 3242378A
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United States
Prior art keywords
cathode
anode
discharge
alive
keep
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Expired - Lifetime
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US201967A
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English (en)
Inventor
Kobayashi Haruhiro
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International Standard Electric Corp
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International Standard Electric 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
    • H01J17/491—Display panels, e.g. with crossed electrodes, e.g. making use of direct current with electrodes arranged side by side and substantially in the same plane, e.g. for displaying alphanumeric characters

Definitions

  • This invention relates to a cold cathode indicator tube, and particularly to a tube of this type which may be utilized in conjunction with low voltage, low current counting circuits.
  • the object of this invention to provide a cold cathode discharge tube operable with a signal input of the order of I a.
  • the invention is promulgated upon what is termed a keep-alive discharge maintained on the surface of a cathode assembly which is opposite that upon which the display is intended.
  • the diffusion of the charged particles into the main gap allows the anode starting voltage to be decreased by the order of 100 volts With the result that a considerable fluctuation of the supply voltage to the anode does not affect stability. Furthermore, it is obvious that the keepalive discharge obviates the problem of darkness.
  • FIG. 1 shows schematically a side view of one embodiment of the invention together with the operating circuit therefor.
  • FIGS. 2, 3, and 4 are individual illustrations for the cathode assembly, anode, and keep-alive cathode, respectively, of the discharge tube of FIG. 1.
  • FIG. 5 is a graphic representation of the trigger characteristics of the discharge tube for a keep-alive current Of 50 ,ua.
  • FIG. 6 illustrates the curve of the control electrode current just prior to the initiation of anode breakdown.
  • the general electrode arrangement may be seen within the gas-filled, sealed envelope 15 (the gas is, for example, neon to which a small percentage of argon is added).
  • the arrangement consists of an annular metal anode 1 of, for example, nickel or nichrome; ten plane cathodes 3 disposed radially and symmetrically about the axis; ten sets of keep-alive cathodes 4 disposed on the opposite sides of the holes with respect to the anode; and ten control electrodes 2 disposed on the anode side. From the above number of elements within each elemental group, it is obvious that a decade indicator has been chosen for the example.
  • the cathode structure seen in FIG. 2, is a molybdenum ring, the face of which is sector coated with insulation 18.
  • the ten sectors 3 each act as a cathode, and contain a hole 5 therethrough for the diffusion.
  • the additional cathode structure having the function of maintaining the discharge, consists of ten keep-alive cathodes 4 (FIG. 4) Welded to an annular ring 16 of nickel or molybdenum.
  • the ten control electrodes or triggers 2 are wires disposed like radial spokes on an imaginary wheel, each spoke being insulated from its neighbor, and appearing in proximity to one of the holes 5.
  • FIG. 1 illustrates only two sets of trigger connections. It will be understood, however, that ten such connections through additional resistors 13 and counting circuit outputs, exist.
  • the main cathodes 3 are grounded while the keep-alive cathodes are supplied, through a common resistor 14, with a negative supply voltage obtained by rectifying (with rectifier 11 and filter 12) the alternating-current voltage of transformer 8.
  • a glow discharge can be induced between the ten keep-alive cathodes and the ten cathodes.
  • a portion of the electrons and ions produced by the glow discharge diffuse through the holes 5 into the space on the anode side.
  • a negative bias voltage applied by a source 9 to the control electrodes 2 provide ion sheaths around the holes.
  • FIG. 5 shows the relation between the critical anode voltage V taken as the ordinate, and the critical control electrode voltage V taken as the abscissa, for a discharge indicator tube according to the invention.
  • the tube is filled with neon gas mixed with 5% argon at mm. Hg, and has a keep-alive cathode current of 50 ta. Inas much as the cathodes are spaced by the insulated layer portions 18, the discharge produced at one cathode is prevented from spreading to its neighbor and only that cathode to which the signal is applied glows in the main discharge gap.
  • the input current required is equal to the control electrode current flowing just before ignition.
  • FIG. 6 shows the values obtained for the control electrode current versus the control electrode voltage V in the case of a floating anode.
  • the cathodes may be in the shape of numerals or alternatively the anode may have numeral slits so that a shaped glow will result.
  • the anode may be supplied with a direct smooth voltage, which value is in the range between the anode sustaining voltage and the maximum anode voltage without self ignition so that the tube, once operated, may be reset by the application of a negative pulse to the anode.
  • a cold cathode gas filled discharge tube comprising an anode; at least one cathode, having an aperture therethrough, disposed in facting relation to said anode and forming therewith a main discharge gap; means for supplying different bias potentials to said anode and cathode; at least one keep-alive cathode, disposed in proximity to said aperture on the side opposite said anode, defining with said first mentioned cathode an auxiliary keep-alive discharge gap; means for supplying a voltage to said keep-alive cathode which is sufficiently more negative than the bias voltage on said cathode to create a glow discharge between said cathodes, and at least one control electrode disposed adjacent said aperture in the main discharge gap; means, including a source of input pulses for supplying said control electrodes with voltages for controlling the diffusion of charge particles into said main gap.
  • a cold cathode gas filled discharge indicator tube for a decade counting circuit comprising an anode; ten electrically connected substantially fiat cathodes each disposed in facing relation to a portion of said anode and forming therewith ten main discharge gaps, each of said cathodes having an aperture therethrough; means for supplying bias voltages to said anode and each of said cathodes ten electrically connected keep-alive cathodes each disposed in proximity to one cathode aperture on the side opposite said anode, defining with said first mentioned cathodes ten auxiliary keep-alive discharge gaps; means for supplying to each of said keepalive cathodes a voltage which is more negative than the voltage on said cathode and which is sufficient to create a glow discharge between said cathode and each of said keep-alive cathodes; and ten control electrodes each disposed adjacent one aperture in the corresponding main discharge gap; means, including a signal input pulse source for supplying each of said control electrodes with a variable voltage for
  • a cold cathode gas filled discharge indicator tube fod a decade counting circuit comprising a circular anode; ten electrically connected substantially fiat cathodes disposed in a circular array, each cathode disposed in facing relation to a sector of said anode and forming therewith ten main discharge gaps, each of said cathodes having an aperture therethrough; means for supplying difierent bias voltages to said anode and each of said cathodes; an annular metal ring having ten axially directed metal fingers mounted thereon, said ring being disposed on the side of said cathode opposite said anode, the unmounted end of each of said fiingers being in proximity to each of said apertures on one-to-one basis and defining with said cathodes ten keep-alive discharge gaps; means for supplying a voltage to said ring which is more negative than the voltage on each of said cathodes and which is suflicient to create a glow discharge between each of said fingers and the corresponding cathode; and
  • a cold cathode gas filled discharge tube having: an anode; a cathode spaced from and facing said anode and having an aperture therethrough; at least one electrode positioned between said anode and cathode and adjacent said aperture; and at least one keep-alive electrode disposed on the side of said cath ode opposite said anode and in close proximity of said aperture, the combination of steps comprising: supplying predetermined different bias potentials to said anode and cathode; creating a glow discharge between said cathode and said keep-alive electrode by applying a voltage to said keep-alive electrode which is more negative than said cathode bias voltage; preventing ion flow through said aperture during preselected intervals by applying a negative voltage to said control electrode which is sufiicient to create an ion shield around said aperture; and varying the potential supplied to the control electrode to alter said shield to permit ion fiow through said aperture.

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US201967A 1961-06-26 1962-06-12 Discharge indicator tube Expired - Lifetime US3242378A (en)

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JP2282161 1961-06-26

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US3242378A true US3242378A (en) 1966-03-22

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US (1) US3242378A (fr)
BE (1) BE619381A (fr)
NL (1) NL279906A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3480820A (en) * 1967-09-08 1969-11-25 Burroughs Corp Indicator tube having auxiliary electrodes for maintaining cathode glow
USRE28683E (en) * 1969-01-07 1976-01-13 Burroughs Corporation Gaseous discharge display panel with auxiliary excitation cells
US4193017A (en) * 1978-01-18 1980-03-11 Ferranti Limited Gas discharge display panel

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2295569A (en) * 1941-11-27 1942-09-15 Bell Telephone Labor Inc Gaseous electron discharge device
US2575372A (en) * 1949-08-09 1951-11-20 Bell Telephone Labor Inc Cold cathode gaseous discharge device
US2928013A (en) * 1954-12-23 1960-03-08 Siemens Ag Electrical discharge device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2295569A (en) * 1941-11-27 1942-09-15 Bell Telephone Labor Inc Gaseous electron discharge device
US2575372A (en) * 1949-08-09 1951-11-20 Bell Telephone Labor Inc Cold cathode gaseous discharge device
US2928013A (en) * 1954-12-23 1960-03-08 Siemens Ag Electrical discharge device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3480820A (en) * 1967-09-08 1969-11-25 Burroughs Corp Indicator tube having auxiliary electrodes for maintaining cathode glow
USRE28683E (en) * 1969-01-07 1976-01-13 Burroughs Corporation Gaseous discharge display panel with auxiliary excitation cells
US4193017A (en) * 1978-01-18 1980-03-11 Ferranti Limited Gas discharge display panel

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Publication number Publication date
BE619381A (fr) 1962-12-27
NL279906A (fr)

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