US3735180A - Data display device of the gas discharge type - Google Patents

Data display device of the gas discharge type Download PDF

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Publication number
US3735180A
US3735180A US00182763A US3735180DA US3735180A US 3735180 A US3735180 A US 3735180A US 00182763 A US00182763 A US 00182763A US 3735180D A US3735180D A US 3735180DA US 3735180 A US3735180 A US 3735180A
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Prior art keywords
cathodes
anode
screen electrode
openings
plates
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Expired - Lifetime
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US00182763A
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English (en)
Inventor
M Coulon
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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
    • 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
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • G09F9/313—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements being gas discharge devices

Definitions

  • ABSTRACT A gas discharge type data display device is formed of a Sept. 24, 1970 France ..70/34663 Stack of alternately conductive and insulating ele ments for localizing the discharge by proper potential [52] 1.8. CI ..3l3/109.5, 313/193 distribution the control of which is effected by a Cl J' 61/66 7/04 ductive screen electrode positioned between anode [58] Field of Search ..313/l09.5, 193, 195;
  • Discharge is confined in a plurality of cavities provided in said stack.
  • the device permits a storage of data in said cavities for an indefinite period of time.
  • This invention relates to display devices which operate by means of an electrical discharge in a gas and which, by virtue of segments or dot matrices, can produce a visual display of data such as letters, digits, signs, characters, symbols and linear profiles of all kinds.
  • the segments or dots constitute the elementary visual units in said display.
  • the elementary visual units are located inside an enclosure into which, after having produced a vacuum there, there is introduced a gas under a certain pressure, generally a rare gas or a mixture of several such gases, or, possibly, mercury vapor.
  • a gas under a certain pressure generally a rare gas or a mixture of several such gases, or, possibly, mercury vapor.
  • the visual units are constituted by conductor segments insulated from one another, the cold cathodes forming these segments are surrounded, in operation, by a light halo produced in their immediate vicinity by ionization of the gas when an appropriate voltage is applied to the common anode of the tube.
  • the anode is connected to the positive terminal of a DC. supply, while each cathode segment is connected, through a switch, to the negative terminal of said supply.
  • voltage is applied to these cathodes in accordance with a given program for operating the switches.
  • the simultaneous display of several segments provides a complete display at the source.
  • the display is achieved, again by gas ionization, by means of a matrix of insulating material provided with holes filled with said gas and located between two networks of generally rectilinear transparent electrodes which cross one another over said holes. A suitable voltage is applied between said electrodes in order to achieve selective illumination of the various holes, the illuminated entirety of which defines in the form of dots the sign which is to be displayed.
  • the decoder is switched successively to each unit.
  • the duration of display time assigned under these circumstances to each unit is inversely proportionate to the number of units.
  • the frequency with which the data are refreshed should take account of the retinal persistance of the human eye in order to avoid flicker and should therefore not be less than 30 cycles per second.
  • the active data-processing memory which is the origin of the data to be displayed and is integrated into the equipment of which the aforesaid display devices form part, should be available for the whole duration of the display time;
  • the unit should be capable of handling a low operating ratio, that is, it should have a substantial dynamic range of light emission. Accordingly, taking into account the permissible power levels in the existing devices, a ratio of between one-tenth and one-twentieth is a minimum.
  • the device in accordance with the invention is not bound by these two requirements. It has an intrinsic memory which thus enables data to be stored indefinitely and thus makes it unnecessary to perform the data refreshing operation. Under these circumstances, the number of units piloted by a single decoder circuit can be considerably increased without being limited by the aforesaid considerations of flicker and brightness.
  • the data display device forming the subject of the present invention which operates by the ionization of a gas inside an envelope and comprises at least one anode and a plurality of cathodes, incorporates a structure formed of stacked, alternating conductor and insulator elements, in order to localize the discharge at the level of each cathode by an appropriate distribution of the potentials.
  • the control of this distribution is effected by the addition of a screen electrode disposed between thecathodes and the anode, and by the shape of a straight section of the volume in which said discharge is confined.
  • the screen electrode and the interspersed insulating elements are provided with openings.
  • the triggering voltage Va is for example volts
  • a markedly higher voltage for example 155 volts is obtained.
  • the magnitude of this voltage is a function of the selected geometry and the bias voltage applied to the screen electrode.
  • FIG. 1 is an exploded isometric view illustrating the component elements of one embodiment of the device in accordance with the invention
  • FIG. 2 is a sectional side elevational view of the same embodiment in an assembled condition
  • FIG. 3 is an exploded isometric view illustrating the component elements forming a part of another embodi' ment of the device in accordance with the invention
  • FIG. 4 is a sectional side elevational view of the part shown in FIG. 3 and FIG. illustrates the voltage-current characteristic of a device in accordance with the invention.
  • FIGS. 1 and 2 relate to the display devices in which the elementary units to be displayed are constituted by segments.
  • the component 1, made of glass or a glassmetal bonded structure, constitutes a conventional base of the type used in electron tube technology and serves as the carrier for the assembly of electrodes in such a tube. Through the insulating glass portions of the base 1 there extend supply leads 2 for the assembly of electrodes of said device as well as a certain number of posts 3 which will be referred to later as the specification progresses.
  • the cathodes 4 are solid metal segments. These cathodes define the shape of the sign which is to be displayed by the device in accordance with the invention. These segments number seven in the present example and are distributed in a conventional way to enable any digit and a certain number of letters of the alphabet, to be displayed.
  • the plate 5 which is made of a refractory insulating material, for example mica or alumina, is provided with openings 5a in a pattern identical to that presented by the entirety of segments 4.
  • the lengths and widths of the openings are slightly larger than the dimensions of said segments so that when the plate 5 has been placed upon the base 1, said openings 5a circumscribe the segments 4.
  • the thickness of the plate 5 is appreciably greater than the of the segments 4, the latter are necessarily recessed in the interior of the openings 5a.
  • the insulating plates 5 and 7 have openings 5a and 7a which are shorter in length and width than the openings (in and 8a in the conductive plates 6 and 8.
  • This geometry of the openings is determined experimentally in order to achieve control of the distribution of the discharge within the cavities 10 not only by the action of the screen electrode but, as explained hereinbefore, by means of the shape of the straight section of the volume or cavity in which the discharge is confined.
  • this kind of arrangement makes it possible to protect the top part of said insulating plates, opposite said conductive plates, against cathode spluttering to thus avoid any leakage conductance between the electrodes 4, 6 and 8.
  • the posts 3 align the assembly of plates 5, 6, 7 and 8 and help to position associated elements such as getters, gas-release or mercury-release capsules, etc., which are conventionally incorporated into devices of this kind but which, for preserving clarity, are not shown in the figures.
  • the plate assembly is secured to the base by known means applied to the posts 3, for example eyelets, pinched-out lugs, etc.
  • Such securing means are well known in the technique of assembling electronic tubes.
  • One method of energizing the device is as followsi
  • the segments 4 which function as cathodes, are grounded.
  • the electrode 8 which is the anode, is placed at a constant potential, for example, for a given geometry, 160 volts.
  • the screen electrode 6 is placed at a positive potential of a value that is between the cathode and the anode potential so that there is no discharge between cathodes and anode.
  • the potential applied to the screen electrode 6 may be for example volts, so that a short negative pulse in the order of 10 volts, applied to those of the cathodes which are to be piloted, brings about the triggering of the discharge in the aforesaid manner.
  • the discharge is maintained indefinitely after said cathodes have reverted to ground potential.
  • commands can be selected by simultaneously applying a -5 volt pulse to the selected cathode and a +5 volt pulse to the anode. It is thus possible to multiplex several units by driving all the cathodes and the anode of the unit selected.
  • the extinction of the discharge over the whole of the unit is effected by applying a 20 volt pulse to the anode.
  • FIGS. 3 and 4 relate to display devices in which dots in a dot matrix constitute the elementary units.
  • the control is effected by an XY coordinate addressing system.
  • the electrodes 14 group together a certain number of such dots in columns.
  • the dots of one column are electrically interconnected.
  • the electrodes 18 select from these dots the ones which are to be controlled.
  • the component 16 is the screen electrode.
  • the discharges corresponding to the various dots are confined to the interior of the cavities 20, the geometry of which is similar to that of the cavities 10 in the first embodiment.
  • the plates 15 and 17 are interposed insulating plates similar to plates 5 and 7 of the first embodiment according to FIGS. 1 and 2.
  • the display device according to the embodiment shown in FIGS. 3 and 4 can be extended as desired to form a display bar, the length of which is limited only by technological considerations.
  • the bar according to FIGS. 3 and 4 comprises, similarly to the first embodiment, a base 11, supply leads 12, centering posts 13 and an envelope 19 which is sealed to the base 11.
  • the devices described can be energized in a different fashion.
  • the grounded electrodes 4 or 14 function as anodes.
  • the electrode 8 or 18 functioning as the cathode is placed at a negative potential, for example -160 volts for a given geometry.
  • the electrode 6 or 16, functioning as the screen is placed at the intermediate potential of l volts for example, in order to block the discharge between cathode and anode in a manner described earlier.
  • the conditions of operation remain the same as in the aforedescribed circuit except that this time positive pulses are used.
  • a multiple display device operating in the above described manner can then be designed as conventional multilayer printed circuits wherein the electrodes are disposed at the surface and the leads between corresponding segments are insulated from one another.
  • the composite circuit thus obtained supports the stack of electrodes and insulators described in connection with FIGS. 1, 2, 3 and 4.
  • a transparent envelope is likewise sealed to the bar thus formed.
  • FIG. 5 illustrates the volt-ampere characteristics relating to one elementary cell.
  • the current remains neglible up to the triggering voltage Va.
  • the current suddenly assumes the value which corresponds to the ordinate of point A and varies thereafter following an arc AC.
  • the current decreases following the curve CA, but is maintained until the point B, the abscissa Ve of which represents the extinguishing voltage.
  • the current again becomes neglible.
  • the afore-described cycle thus represents a hysteresis characterized by the area of the quadrangle Ve, Va, A, E.
  • the voltages between Va and Ve correspond to metastable operational points of the discharge.
  • the discharge is and remains established if the triggering voltage Va has been previously exceeded.
  • the discharge is not established and is not initiated if previously the voltage has been lowered below the value of Ve.
  • the quadrangle Ve, Va, A, E thus bounds the domain in which there exists the memory phenomenon of the device forming part of the invention.
  • the structure forming the subject of the invention is adaptable to all the known forms of display; its application therefore extends to any known form of illuminated data display, in particular the display in one plane of arbitrary linear profiles by means of a dot matrix.
  • low-amplitude pulse control adapted to be utilized with all the logic systems currently industrially developed; this control is compatible in particular with integrated circuits which combine the complex functions of multiplexing, code conversion and control, whatever the polarity involved;
  • This local memory is fully exploited whenever data requires distribution to several users or storing for a substantial period of time. It makes possible a more efficient use of active data processing memories which originate the information to be displayed, and in some applications makes it unnecessary to provide a supplemental refresher memory.
  • a data display device of the gas discharge type comprising A. at least one anode,
  • D. means defining a plurality of cavities, each containing one of said cathodes for confining the discharge within as many independent volumes as there are cathodes and
  • E. means disposed between said cathodes on the one hand and said anode on the other hand for forming, together with said cathodes and said anode, an intrinsic memory in said device to store data therein for an indefinite period of time, said last-named means including 1. a screen electrode and 2. insulating elements disposed between said cathodes and said screen electrode and between said screen electrode and said anode.
  • said anode and said screen electrode are formed as metal plates positioned over the plurality of said cathodes in a superposed relationship
  • said insulating elements are constituted by a first insulator plate disposed between said cathodes and said screen electrode and by a second insulator plate disposed between said screen electrode and said anode
  • each metal plate and each insulator plate is provided with a plurality of openings in an arrangement and configuration corresponding to those of said cathodes, the openings in different plates are in alignment to define said cavities.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Gas-Filled Discharge Tubes (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
US00182763A 1970-09-24 1971-09-22 Data display device of the gas discharge type Expired - Lifetime US3735180A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7034663A FR2106803A5 (enrdf_load_stackoverflow) 1970-09-24 1970-09-24

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US3735180A true US3735180A (en) 1973-05-22

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FR (1) FR2106803A5 (enrdf_load_stackoverflow)
GB (1) GB1363672A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3864593A (en) * 1972-05-23 1975-02-04 Ise Electronics Corp Flat fluorescent letter display tubes
US4259613A (en) * 1978-01-11 1981-03-31 Wagner Electric Corporation Fluorescent indicator and method of making same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2831962C3 (de) * 1978-07-20 1981-02-26 Siemens Ag, 1000 Berlin Und 8000 Muenchen Kathode für eine Gasentladungsanzeigeröhre

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3559190A (en) * 1966-01-18 1971-01-26 Univ Illinois Gaseous display and memory apparatus
US3641383A (en) * 1968-09-25 1972-02-08 Matsushita Electronics Corp Glow discharge tube for code display

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3559190A (en) * 1966-01-18 1971-01-26 Univ Illinois Gaseous display and memory apparatus
US3641383A (en) * 1968-09-25 1972-02-08 Matsushita Electronics Corp Glow discharge tube for code display

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3864593A (en) * 1972-05-23 1975-02-04 Ise Electronics Corp Flat fluorescent letter display tubes
US4259613A (en) * 1978-01-11 1981-03-31 Wagner Electric Corporation Fluorescent indicator and method of making same

Also Published As

Publication number Publication date
GB1363672A (en) 1974-08-14
DE2147881A1 (enrdf_load_stackoverflow) 1972-03-30
DE2147881B2 (de) 1975-11-20
FR2106803A5 (enrdf_load_stackoverflow) 1972-05-05

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