US3832706A - Gas discharge display panels having conditioning cells - Google Patents

Gas discharge display panels having conditioning cells Download PDF

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Publication number
US3832706A
US3832706A US00316463A US31646372A US3832706A US 3832706 A US3832706 A US 3832706A US 00316463 A US00316463 A US 00316463A US 31646372 A US31646372 A US 31646372A US 3832706 A US3832706 A US 3832706A
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cells
conditioning
display
signal
signals
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US00316463A
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English (en)
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J Reboul
J Portmann
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Thales SA
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Thomson CSF SA
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/28—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels
    • G09G3/288—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels
    • G09G3/291—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels controlling the gas discharge to control a cell condition, e.g. by means of specific pulse shapes
    • G09G3/292—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels controlling the gas discharge to control a cell condition, e.g. by means of specific pulse shapes for reset discharge, priming discharge or erase discharge occurring in a phase other than addressing
    • G09G3/2927—Details of initialising
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/28—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels
    • G09G3/288—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels
    • G09G3/297—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels using opposed discharge type panels

Definitions

  • the present invention relates to improvements in display systems employing display panels of the gasdischarge kind, which improvements in particular make it possible to improve the rapidity of their response to writing signals, that is to reduce the time lag extending between the application of a control signal to the panel and the effect produced by this signal, in other words the display.
  • Such display panels are generally constituted by a network of cells filled with a gas or gas mixture, the ionization of which is controlled by signals applied to an intercrossing network of electrodes.
  • these cells are materially delimited and separated from one another; such embodiments comprise insulating matrices provided with gas filled holes, the control electrodes,
  • the thus activated or written cell i.e., having a storage voltage, is then subjected to an alternating electric field produced by a holding signal applied to the panel assembly, which field is insufficiently strong to ionise the unwritten cells but sufficiently strong to ionise the written cells which then briefly light up twice per cycle of the holding signal.
  • a major and delicate problem which has to be resolved in this context is that of the conditioning" of these panels.
  • rapid response by a panel to a writing signal is only possible if the ionization of the cells to be recorded takes place as soon as the writing signal is applied.
  • the gas shall contain a sufficient number of free electrons to produce rapid electron avalanche and therefore ionisation. If no particular precaution is taken to ensure that the panel permanently has such free electrons, these being known as conditioning electrons, then in the response of the cells a lag time occurs which may be as much as several seconds and thus considerably limits the field of application of the panel.
  • One simple method consists in distributing within the gas a small dose of a radioactive product which slightly ionizes the gas and thus creates conditioning electrons.
  • Another method used is an electrical conditioning which consists in ionising the set of cells at a frequency very much lower than that of the holding signal, whilst arranging that after this ionisation they retain the state which they had before (i.e., written cell or not written cell). Unfortunately, such a method is difficult to be correctly carried out and disturbances may appear in the display.
  • Optical conditioning methods are also known in which the conditioning electrons are photo-electrons produced in the gas by a light source, which may be outside the panel, but which then disturbs its observation, or by permanent illumination of the peripheral cells of the panel. This permanent illumination, excludes certain types of control. Moreover, conditioning is only properly effected for panels without matrices. The ultravioled rays produced by the luminescence of the peripheral cells would be very highly attenuated by a matrix and would quickly become inadequate to produce photoelectrons in cells at any distance from the periphery.
  • the present invention is concerned with gas discharge display panels with or without matrix, in which the conditioning is effected in an efficient manner by a special optical method.
  • a certain number of cells distributed over the whole of the surface of the panel are reserved exclusively for the conditioning function; the electrodes which control them are supplied permanently and solely with signals having a sufficient amplitude to briefly ionise these cells at a frequency much lower than the frequency of the holding signal applied to the other cells of the panel, in order not to disturb the display.
  • the number of cells reserved for the conditioning operation, and their distribution within the panel, depend upon the type of information to be displayed and are based upon a compromisebetween adequate conditioning to permit rapid display but at the same time not too important to not disturb the observation of the display, the cells thus used for the conditioning function not being usable for the display function.
  • a display system with a gas discharge display panel comprising a network of cells filled with gas ionizable on application of signals of appropriate amplitude between electrodes for controlling said cells, said control electrodes constituting a network of intercrossing electrodes disposed in lines and columns, an alternating holding signal of periodicity T being applied between the control electrodes of the cells used for display, and producing, twice per cycle T the ionisation of.
  • the written cells that is to say the cells already ionised by the application of a writing control signal and a conditioning of the panel being realised for providing within said panel some free electrons, said contioning being realised by means of certain predetermined cells known as conditioning cells, distributed over the whole of the surface of the panel and being utilised only for said conditioning function, signals of an amplitude high enough to provoke ionisation of said conditioning cells being provided between the electrodes controlling them at a frequency n times higher than the frequency l/T of said holding signal.
  • FIG. 1 illustrates graphs showing theform of different signals applied to the panels of the systems in accordance with the invention
  • FIG. 2 illustrates a partial, schematic view of an embodiment of a system in accordance with the invention.
  • cells distributed over the whole of the surface of the display panel are reserved exclusively for the conditioning function.
  • a certain number of electrodes of the intercrossed network that is to say a certain number of line and column electrodes, are not supplied with any of the display control signals proper (holding signals, writing signals, erase signals. but only with conditioning signals in accordance with the invention.
  • FIG. 1 schematically illustrates the shape of the signals applied between the control electrodes of cells involved in the display, or display cells, (a) and of cells reserved for conditioning (b) and two possible variant forms of the latter having been given.
  • the signals are here represented in the form of a voltage V as a function of the time 2, this voltage being the potential difference between the two electrodes intercrossing over a cell and thus controlling it. They will,
  • the holding signal S E is an alternating signal of periodicity T, and amplitude V permanently applied to the system of display cells.
  • a writing signal 3, consisting for example in an over-amplitude in the holding signal, sufficient to ionise the cells concerned, is applied to the cell or cells which are to be displayed.
  • the problems of erasing are not dealt with here since in order to erase a written cell which is ionised twice per holding period T there is of course no need for conditioning.
  • the conditioning signals S in accordance with the invention are permanently applied to particular cells of the panel, reserved for the conditioning function, through the medium of corresponding electrodes. They have an amplitude 8, higher than or equal to S sufficient to ionise said conditioning cells. They may consist of a pulse of amplitude V applied to the conditioning cells with a frequency 11 times less than that of the holding signal; the conditioning cells are thenionised twice per cycle T nT They may equally be arranged to ionise only once per cycle T if the polarity of the applied signal only reverses with each cycle T In FIG. 1, the conditioning signal is constituted by two half-waves of a rectangular waveform signal of periodicity T repeated at a periodicity of T nT This results in two ionizations of the conditioning cells.
  • the ionization of the conditioning cells produces a light level much lower than that of the display cells which are regularly ionised 2n times per cycle T
  • the brilliance of the display cells is around n times greater than that of the conditioning cells.
  • the light emitted by the conditioning cells during ionisation produced photoelectrons in the neighbouring cells and thus facilitates their writing. If the conditioning cells are suitably distributed within the panel, then the whole system will be conditioned.
  • the conditioning signals S are supplemented by a signal, 4 or 8, identical to the conditioning signals S but applied synchronously with the writing signals
  • the photoelectrons thus produced in the conditioning cells enable the neighbouring cells to ionise reliably as soon as the writing signal is applied.
  • the two graphs (b) and (c) correspond to two possible variant embodiments, the signals S being applied respectively in phase opposition with the holding signals S or co-phasally therewith, the supplementary signal 4 or 8 in all cases being applied synchronously with the writing signal S,.
  • the result of this may be, depending upon whether the variant (b) or (c) is chosen, a differing level of ionization of the conditioning cell, as explained hereinafter in reference to FIG. 2.
  • the ratio n between the frequency of the holding signal and that of the conditioning signal is chosen sufficiently large for the contrast between the written and conditioned cells, to be good, this contrast being approximately equal to l/n.
  • n is chosen sufficiently large for the contrast between the written and conditioned cells, to be good, this contrast being approximately equal to l/n.
  • n is made sufficiently small for the conditioning cells to light up without delay as soon as the conditioning signals are applied.
  • a conditioning time of less than 2 ms is required.
  • n 50 produces excellent contrast and faultless lighting of the conditioning cells.
  • FIG. 2 illustrates in a highly schematic manner, part of a display panel P forming part of a display system in accordance with the invention.
  • This panel P is entirely conventional in design and has not been described itself; embodiments of such panels are referred to in the aforementioned patent application.
  • the electrodes are constituted by an intercrossing network of line electrodes EL EL EL EL EL EL EL represented in continuous line and column electrodes E E E E represented in broken line, to illustrate the fact that in relation to the line electrodes they are located on the other face of the panel P.
  • the invention is applicable equally to a panel with a matrix or to a panel without a matrix.
  • the gas cells are each located at the point where the control electrodes are crossing.
  • the panel P is divided into small rectangular display areas, s s for example, surrounded by frames reserved for conditioning.
  • the network of elec- For this purpose, the network of elec-.
  • the holding S and recording S, signals are applied, in the form of symmetrical half-levels for example, between the line and column electrodes of the display portions; the conditioning signals S are applied in the same manner, between the conditioning electrodes.
  • the display cells are represented by small circles, white for extinguished cells and black for illuminated cells which form a letter P in the surface s,.
  • conditioning control circuits in accordance with the invention has been schematically illustrated in said same FIG. 2.
  • a code converter element 21 receives at 22 the data which are to be displayed and supplies the different conventional control signals and addressing signals. lt controls a clock 23 the frequency H of which is, for example, that of the holding signals 8,; and which synchronises the whole control circuits. This clock 23, through shaper circuits which have not been shown,
  • the blocks 24 and 25 symbolise modulators transmitting the holding signal which they receive at E, in the absence of any writing data I, and a higher amplitude signal S, when they receive a data signal, the code converter element of course controlling the addressing of these data by the line and column selectors 26 and 27, respectively.
  • the conditioning signals S are for example generated in'the following manner.
  • a frequency-divider 28 receives the clock signals 23 and produces signals of frequency H/n l/T which are supplied to a shaper element 29 producing conditioning signals 5, out of phase by in relation to the holding signals S E in the variant illustrated here.
  • These signals suitably amplified at 30 and 31, are applied in the form of symmetrical half-levels between the line and column electrodes reserved for the conditioning function. They are applied to the amplifiers 30 and 31 through the medium of adder circuits 32 and 33 of the OR-gate type, to whose first inputs they are applied.
  • the second input of these OR-gates is supplied in each case with a supplementary conditioning signal which is said signal in synchronism with the writing signals 8,.
  • a coincidence circuit 34 for example, and AND-gate, is supplied with signals at the frequency H of the clock 23, suitably shaped, and is open on a command from the code converter element 21 when writing takes place.
  • the cells of the panel which are the closest those which are used for conditioning have a higher probability of being quickly written.
  • the supplementary conditioning signal applied during writing although producing supplementary ionization of the conditioning cells produces no substantial degradation in the contrast because the sequences of recording are too short for the observer to be able to see the brief change in brilliance at the conditioning points.
  • the conditioning cells may not illuminate until after a few seconds as they are not themselves conditioned. This delay can be reduced by providing in these conditioning cells a small dose of a radioactive product, for Example, l micro-cutie of radium bromide.
  • a display system with a gas discharge display panel comprising a network of cells filled with gas ionisable on application of signals of appropriate amplitude between electrodes for controlling said cells, said control electrodes constituting a network of intercrossing electrodes disposed in lines and columns, means for applying an alternating holding signal of periodicity T between the control electrodes of the cells used for display, and producing, twice per cycle T the ionisation of written cells already ionized by tha application of a writing control signal, and means for conditioning the panel for providing within said panel some free electrons, said conditioning means comprising certain predetermined cells known as conditioning cells, distributed over the whole of the surface of the panel and being utilised only for said conditioning function, and means for providing conditioning signals of an amplitude high enough to provide ionisation of said conditioning cells between the electrodes controlling them at a frequency n times lower than the frequency UT, of said holding signal.
  • a display system as claimed claim 1 wherein the application of a writing signal between the control electrodes of display cells, controls the application, to the control electrodes of the conditioning cells, of a conditioning signal which ionises said conditioning cells as 8 soon as said writing signal is applied.
  • a display system as claimed in claim 1 utilized for displaying alphanumerical characters, one character being displayed by a group of adjacent display cells, wherein said control electrodes are connected to sup- I ply means delivering said control and conditioning signals with said conditioning cells between and adjacent to said groups of display cells.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Plasma & Fusion (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
US00316463A 1971-12-23 1972-12-19 Gas discharge display panels having conditioning cells Expired - Lifetime US3832706A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7146397A FR2165266A5 (de) 1971-12-23 1971-12-23

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US3832706A true US3832706A (en) 1974-08-27

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US (1) US3832706A (de)
JP (1) JPS4874117A (de)
DE (1) DE2263050A1 (de)
FR (1) FR2165266A5 (de)
GB (1) GB1418037A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3916253A (en) * 1974-04-25 1975-10-28 William A Driscoll Pulse distribution system
US3976971A (en) * 1974-03-05 1976-08-24 Nippon Electric Company, Ltd. Gas-discharge display panel having a third group of electrodes forming control discharge spaces
US3986185A (en) * 1974-12-23 1976-10-12 Texas Instruments Gas discharge display with control cells
US4524352A (en) * 1982-06-04 1985-06-18 International Business Machines Corporation High frequency pilot

Families Citing this family (4)

* 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
JPS5367317A (en) * 1976-11-27 1978-06-15 Nec Corp Plasma display device
JPS5451330A (en) * 1977-09-29 1979-04-23 Nec Corp Driving method for dischage display panel
JPS5522773A (en) * 1978-08-08 1980-02-18 Nippon Electric Co Driving discharge display panel

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3509421A (en) * 1967-09-11 1970-04-28 Burroughs Corp Plasma gas-filled display device
US3644925A (en) * 1969-01-07 1972-02-22 Burroughs Corp Gaseous discharge display panel with auxiliary excitation cells

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3509421A (en) * 1967-09-11 1970-04-28 Burroughs Corp Plasma gas-filled display device
US3644925A (en) * 1969-01-07 1972-02-22 Burroughs Corp Gaseous discharge display panel with auxiliary excitation cells

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3976971A (en) * 1974-03-05 1976-08-24 Nippon Electric Company, Ltd. Gas-discharge display panel having a third group of electrodes forming control discharge spaces
US3916253A (en) * 1974-04-25 1975-10-28 William A Driscoll Pulse distribution system
US3986185A (en) * 1974-12-23 1976-10-12 Texas Instruments Gas discharge display with control cells
US4524352A (en) * 1982-06-04 1985-06-18 International Business Machines Corporation High frequency pilot

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FR2165266A5 (de) 1973-08-03
JPS4874117A (de) 1973-10-05
GB1418037A (en) 1975-12-17
DE2263050A1 (de) 1973-07-05

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