US3704389A - Method and apparatus for memory and display - Google Patents

Method and apparatus for memory and display Download PDF

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US3704389A
US3704389A US49436A US3704389DA US3704389A US 3704389 A US3704389 A US 3704389A US 49436 A US49436 A US 49436A US 3704389D A US3704389D A US 3704389DA US 3704389 A US3704389 A US 3704389A
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conductors
conductor
coversheet
voltage
pair
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Walter B Mcclelland
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AT&T Teletype Corp
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Teletype Corp
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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 A plasma-discharge display and data storage device wherein a glow discharge condition in a gas-filled, dielectric envelope is transferred from a region between a pair of transferor electrode conductors to a region between a pair of transferee electrode conductors by causing an AC voltage applied between the transferee electrode conductors to cause an associated potential field inside the gas-filled envelope to reach a glow-discharge-sustaining magnitude prior to the time that the AC voltage applied between the pair of transferor electrode conductors causes an associated potential field within the gas-filled envelope to reach a magnitude sufficient to sustain a glow discharge; and a tapered electrode conductor in which -a plasma or glow discharge in the gas occurs preferentially near the wide end of the tapered electrode conductor.
  • This invention relates to display and memory and more particularly to a method and apparatus for memory and display wherein a gas discharge occurs in an envelope having an inside environment significantly larger than that needed for a single discharge.
  • This invention relates to a plasma discharge device of the type having a gas in a confined area or envelope between a pair of dielectric sheets or coversheets forming an envelope, each sheet having at least one conductor thereon with the conductors being located on the outsides of the sheets and opposite one another across the gas-filled space.
  • the ionization of the gas takes place when a predetermined voltage exists across the gasfilled space inthe envelope formed by the dielectric sheets, causing a portion of the gas to glow momentarily.
  • the gas-filled space has an area thatv is significantly greater than the size required to support'a single glow discharge.
  • the shape of the gas-filled envelope relative to the :shape of atleast one of the conductors is such j that, upon the application of a sufficient voltage across the gas in the region of the conductors, the gas thus ionized covers-an area on the dielectric sheet adjacent to at least one of the conductors, which area varies in a j predetermined manner so that the application of voltfield extending from one conductor through one sheet of dielectric glass, the gas, and the other sheet of glass to the other, crossing conductor, causes the gas in the hole in the center glass sheet between the two orthogonal conductors to ionize to a glowing plasma and thus generate a display.
  • a memory or display condition is made to move from one pair of electrode conductors to another pair of electrode conductors. This is accomplished by causing an AC sustaining voltageto occur sooner between the other pair of electrode conductors'than between the one pair of electrode conductors.
  • Still another object of the present invention is a plasma shift register
  • FIG. 1 shows one tapered conductor on a gas-filled dielectric envelope
  • FIG. 2 is a cross-sectional viewof the device'shown in FIG. 1 taken along line 2-2 of FIG. 1 and showing two glass sheets which together with end pieces form a gas-filled envelope, having conductors positioned on the sides of the glass sheets opposite the gas-filled space;
  • FIG. 3 shows the gas-filled envelope of FIG. 1 but with the conductor arranged in discrete increments of areas;
  • FIG. 4 shows an envelope with conductors of uniform width but the envelope is tapered
  • FIG. 5 shows .a conductor with discrete areas of uniform width and with a'tapered envelope
  • FIG. 6 shows several individual conductors on a single envelope
  • FIG. 7 is a cross-sectional view of the envelope of FIG. 6 taken along the line 7--7;
  • FIG. 8 shows an ignition electrode and several tapered electrodes for advancing a glow discharge condition in steps from one electrode to another;
  • FIG. 9 shows an arrangement of conductors for performing a shift register function according to the present invention.
  • FIG. 15 shows a two-part orthogonal pattern of conductors .for stepping a signal in either direction, thus forming a bi-directional data shift register
  • FIG. 11 shows the shift register of FIG. arranged in a folded configurationthat is particularly useful for display purposes
  • FIG. 12 shows the shift register of FIG. 10 with an encoding system and provision for transferring a glow discharge condition from one shift register to another;
  • FIG. 13 illustrates an adaptation of the shift registers of FIGS. 1 l and 12 to encode a font of display characters, advance them to a display panel, and propagate the characters along the display panel.
  • the dielectric nature of the glass sheets 20 and 22 and of the gas in the space 26 causes an AC voltage divider effect to occur; and a voltage difference develops between the inside surfaces of the glass sheets 20 and 22.
  • this voltage difference equals the firing voltage of the gas, the gas ionizes to a plasma and a glow discharge takes place.
  • the maximum electric field between the two conductors at any location along the length of either of the two conductors 28and 30 occurs atthe center of its width. Due to edge effects, the maximum field due to the applied voltage occurs at the center of the widest portion of the tapered conductor because of the fringing effects of the field at the edges of a parallel plate capacitor such as that formed by the glass and gas between the two conductors. Therefore, glow discharge begins between the conductors 28 and 30 at the center of the widest end of the tapered conductor 30; and as the voltage continues to increase above the minimum voltage necessary to initiate discharge, the
  • the ionization and glow discharge will first take place at the widest point in the gas-filled space 26.
  • the electrode conductor 30 comprises discrete areas of uniform length and width but is positioned over a tapered gas-filled space 26 (FIG. 5)
  • the glow discharge first takes place adjacent the conductor area nearest the wide portion of the gas-filled space 26. This is similar to the phenomenon that occurs with a gas-filled space of uniform width but with a conductor having discrete areas of different size as is shown in FIG. 3.
  • this charge collected on the inside surface of the glass sheet is the essence of the memory of such a system.
  • This capacitively-collected charge functions to reduce the AC voltage level that must be applied between the opposing electrode conductors in each half-cycle after thein'itial ionization in order to reionize the gas.
  • a pair of planar glass sheets or-coversheets 31 and 32 define a neon-gas-filled space or envelope 34.
  • Four electrode conductors 35, 36, 37, and 38 are affixed to the outer surface of the glass sheet 32.
  • the electrode conductors 35, 36, 37 and 38 are placed very near to one another but are mutually separated or insulated from each other.
  • a common electrode conductor 40 is affixed to the outer surface oftheglasssheet3l.
  • a sufficiently high AC voltage is applied between the electrode conductors 36 and 40 by a voltage generator 41 that is electrically connected to the electrode conductors 36 and 40, a momentary glow discharge will occur at each half-cycle until sufficient charges collect in that half-cycle on the inner surfaces of theglass sheets 31 and 32 in the region around the electrode conductor 36 as shown generally by two clouds 42.
  • the voltage that must be applied across the electrodes in order to initiate or ignite a glow discharge will vary with the area of the electrodes, the nature of the gas and its pressure, the nature and thickness of the glass coversheets and their separation, and the presence or absence of ambient ultraviolate light, etc. This might require, typically, 1,000 volts peak-to-peak.
  • a wide range of AC frequencies is possible. A range of from 40 kilohertz to 300 kilohertz has proven convenient, but higher and lower frequencies are possible.
  • the voltage generator 41 can reduce the AC voltage applied between the electrode conductors 36 and 40 to a value sufficient only to sustain a glow discharge typically between and 300 volts less,
  • the polarity of the charge and the instantaneous polarity of the AC voltage must add to each other in order for discharge to occur.
  • the applied voltage is an AC voltage
  • the proper polarity in any case will soon occur after the application of the AC voltage.
  • this AC voltage must be of insufficient magnitude to cause a glow discharge to occur in the absence of collected charges from a previous glow discharge, for example at electrode 38.
  • the memory phenomenon in the form of a collected charge under the electrode conductor 36 can be transferred to the electrode conductor 35 without generating a new cloud of charges at the electrode conductor 38.
  • the cloud of charges 42 is not wide enough to extend as far as the remote electrode conductor 38.
  • this device can be used in a purely data-handling application. In such an application, the glow discharge phenomenon must be reduced to a purely electrical manifestation.
  • the current drawn from the voltage generator 44 can be sensed; or the electrode conductor 35 can be made of a transparent, conductive material, well known in the art; and a photocell 46 can be used to sense the glow discharge.
  • an electrostatic probe conductor can be used to sense the charge resulting from a glow discharge.
  • the glow discharge phenomenon is transferred from the electrode conductor 36 to the electrode conductor 35 by simultaneously increasing the AC voltage applied to the electrode conductor 35 and decreasing the AC voltage applied to the electrode conductor 36.
  • a glow discharge occurs first at the transferee electrode conductor 35, it will rob the transferor electrode conductor 36 of its accumulated charge, thereby preventing the electrode conductor 36 from experiencing a glow discharge even though it might subsequently reach an instantaneous voltage equal to or even slightly exceeding thepeak voltage attained by the electrode conductor 35. Consequently, the transfer of a glow discharge or memory condition may even be accomplished by a phase change between the AC voltage applied to the electrode conductor 36 and the AC voltage applied to the electrode conductor 35.
  • this same transfer result may be accomplished by adjusting the AC voltage levels, as mentioned previously.
  • One AC voltage may be maintained or held constant and the other AC voltage may be decreased or increased.
  • one AC voltage may be decreased simultaneously with an increase of the other AC voltage.
  • the AC voltage of the transferee electrode conductor' is both increased and advanced, while the AC voltage of the transferor electrode conductor is both reduced and retarded in order to transfer a glow discharge condition from the transferor electrode conductor to the transferee electrode conductor.
  • the electrode conductor 40 cooperates with both of the electrode conductors 35 and 36.
  • the electrode conductor 40 could actually be two electrode conductors, one associated with the electrode conductor 36 and the other associated with the electrode conductor 35. Therefore, the voltage generator 41 could provide an AC voltage between one pair of electrode conductors, including the electrode conductor 36.
  • the voltage generator 44 could provide an AC voltage between another pair of electrode conductors, including the electrode conductor 35.
  • FIG. 8 a structure similar to FIGS. 6 and 7 is shown but with uniquely-shaped electrode conductors to cause a memory signal to change from one electrode conductor to another and back again in a controlled advance along both conductors.
  • FIG. 8 a structure similar to FIGS. 6 and 7 is shown but with uniquely-shaped electrode conductors to cause a memory signal to change from one electrode conductor to another and back again in a controlled advance along both conductors.
  • the glass sheet32 is shown with the electrode conductor 36 acting as an ignition electrode. That is,when a signal is to be generated, a sufficient AC voltage is applied between the electrode conductor 36 and the common electrode conductor 40 (see FIG. 7) to cause a glow discharge inevitably to occur adjacent to the electrode conductor 36, without the aid of any charges that between and 50 cycles depending upon many factors may have collected on the insides of the glass sheets 31 v and 32 (see FIG. 7).
  • This glow discharge causes charges to collect on the inside surfaces of the parallel glass sheets 31 and 32 adjacent to the electrode conductor 36 (FIG. 8). This charge distribution on the inside surfaces of the glass sheets 31 and 32 at the electrode conductor 36" is again represented by the cloud outline 42.
  • this cloud of charge 42 extends beyond the edges of the electrode conductor 36 and overlaps a portion of a nearby intermediate electrode conductor 50.
  • the AC voltage applied to the electrode conductor 36 can then be reduced. If an AC voltage signal is applied to the electrode conductor 50, that is not of sufficient voltage to cause a glow discharge to occur unless aided by the charges of the cloud 42, no glow discharge will occur at the wide portion of the electrode conductor 50. However, since part of the cloud of charge 42 extends over a portion of the electrode conductor 50, that cloud of charge aids the voltage that is developed between the electrode con ductor S0 and the common conductor 40 (FIG. 7). On the occurrence of the proper polarity and magnitude of AC voltage signal at the electrode conductor 50 coupled with a significant reduction or retardation of the AC voltage applied to the electrode conductor 36 a glow discharge will occur in the region where the cloud ductor 50.
  • a glow discharge preferentially occurs at the wider portion of an electrode conductor since the field at the center of a wide portion of the conductor is greater than the field at a narrow portion of the conductor. Consequently, at each successive cycle of the AC voltage signal that is applied to the electrode conductor 50, the glow discharge phenomenon migrates from the narrow end of the conductor 50 to the wider end at the right of the electrode conductor 50. This has been found to require of charge 42 overlaps a portion of the electrodecon- I including the size of the electrode conductor and the degree of its taper as well as the magnitude of the applied AC voltage.
  • the glow discharge condition always be maintained at the electrode conductor 36. Therefore, the AC voltage applied to the electrode conductor 50 is normally main tained so as to prevent the transfer of a glow discharge condition from the electrode conductor 36. However, when a glow discharge condition is desired for purposes to be discussed subsequently, the AC voltage on the electrode conductor 50 can be controlled so as to transfer a glow discharge condition from the electrode conductor 36.
  • This glow discharge at the electrode conductor 50 deposits its own cloud of charge 52 on the inside surface of the glass sheet 31 and 32. Sufficient voltage is applied to the electrode conductor 50 to cause the cloud of charge 52 to'overlap the narrow end of another electrode conductor 54 which has. a tapered shape similar to the electrode conductor 50. Therefore, a subsequent AC voltage signal of comparable magnitude applied to the electrode conductor 54 accompanied by a reduction in the AC voltage applied to the .electrode conductor 50 causes a glow discharge to occur at the electrode conductor 54 where it is overlapped by the cloud of charge 52.
  • the occurrence of a glow discharge at the narrow end of the electrode conductor 52 takes charges from the wide endof the electrode conductor 50 and starves the electrode conductor 50 of its charge cloud 52. The glow discharge in the region adjacent the electrode conductor 54 draws the collected charges away from much of the area of the electrode conductor 50.
  • this cloud of charge 62 overlaps another tapered electrode conductor 64. If an AC signal is applied to the electrode conductor when the AC signal applied to the electrode 54 is reduced, a glow discharge will occur at the portion of the conductor 64 that is overlapped by the cloud 62. The occurrence of a glow discharge at the electrode conductor 64 draws charge from the cloud 62, starving the electrode conductor 54 of its charge of favorable polarity. This causes the glow discharge at the electrode conductor 54 to be extinguished even though an AC voltage signal is still applied to the electrode conductor 54. The
  • a binary bit of information generated at the electrode conductor 36 can be transferred to the electrode conductor 50.
  • this bit of information can be advanced to the right in FIG. 8. This bit of information is thus moved from one set of electrodes 54 to the other set of electrodes 64, and back again, in the form of a glow discharge.
  • FIG. 9 there is shown a series of interconnected shift registers that can be mounted on the same glass sheet 32.
  • a sufficiently high AC voltage is applied between the igniting electrode conductor 36 and a common electrode conductor 40 (now shown in FIG. 9).
  • This glow discharge is then transferred to an intermediate electrode conductor 50 and subsequently to an electrode conductor 54 having several segments on it designated by the numbers 54-1, 54-2, etc.
  • the glow discharge can then be transferred from the electrode conductor segment 54-1 to the first segment 64-1 of the companion to electrode conductor 64, having several segments 64-1, 64-2, etc.
  • this signal or binary bit in the form of a glow discharge can be transferred from the electrode conductor segment 54-1 to the electrode conductor segment 64-1 and back to the electrode conductor 54 but on the segment 54-2 and then to the electrode conductor segment 64-2, etc., as far to the right as possible, as shown in FIG. 9.
  • the several segments of the electrode conductors 54 and 64 together form a shift register.
  • a plurality of orthogonal electrode conductors 67, 68, 69 and 70 are electrically connected to the electrode conductor 64 and thus experience the same AC voltage signals that are applied to the electrode conductor 64.
  • a plurality of independent electrode conductors 72, 74, 76 and 78 are arranged substantially parallel to the electrode conductors 67, 68,69 and 70.
  • the electrode conductors 72 and 67 together form another shift register.
  • the electrode conductors 74 and 68 together form a shift register. The same is true with the electrode conductors 76 and 69 and with the electrode conductors 78 and 70.
  • the binary bit signal represented by the glow discharge can then be held at the electrode conductor segment 72-1 and is moved to its wider end by continued AC voltage excitation of the electrode conductor 72, while an additional binary bit signal is transferred from the firing electrode conductor 36 to the interrnediate electrode 50.
  • the additional signal is transferred from the segment 54-1 to the segment 64-1, the previous signal at the segment 72-1 is transferred to the segment 67-1.
  • the additional signal can then be transferred to the segment 54-2 and so forth down the shift register comprising the electrode conductors 54 and 64.
  • the data must be sensed at predetermined points and at predetermined times in order to ascertain whether or not a glow discharge occurs at any given electrode conductor segment. This can be accomplished, for example, by a properly-positioned photocell as describedand shown in connection with FIGS. 6 and 7.
  • a sensing electrode conductor 77 can be placed on the glass coversheet 32.
  • a bit sensor 79 can then be connected to the sensing electrode conductor. If a glow discharge occurs at the adjacent electrode conductor segment 72-3, a charge cloud near the wide end of the electrode conductorsegment 72-3 will overlap the sensing electrode conductor 77. The glow discharge can then be transferred to the sensing electrode conductor 77 by a voltage generator contained in the bit sensor 79 by the technique described above. The current sent to the sensing electrode conductor 77 by the bit sensor 79 can then be measured to determine whether or not there actually was a bit of data transferred from the electrode conductor segment 72-3 to the sensing electrode conductor 77. Once measured,
  • the data bit can be transferred back to the electrode conductor segment 72-3.
  • a charge sensor such as a field-effect transistor could-be used to sense the charge over-lapping the, sensing electrode conductor 77 from the electrode conductor segment 72-3 in the presence of a glow discharge.
  • a glow discharge will remain at the electrode conductor segment 54-1 and will not transfer to the electrode conductor 64-1 so long as the AC voltage applied to the electrode conductor 54 is greater than the AC voltage applied to the, electrode conductor 64.
  • the volt age across the gas between the glass sheets rises faster under the electrode conductor 64 than it does under the electrode conductor 54. Therefore, the glow discharge will occursooner under the electrode conductors 64 than it will occur under the electrode conductor 54.
  • the important consideration in this transfer of the glow discharge condition is not so much the absolute magnitude of the AC voltage applied to an electrode conductor on the glass sheet 32 but relates principally to the relationship between the voltages applied to the electrode conductors 64 and 54.
  • the only requirement of the absolute magnitude of the AC voltage level is that the higher of the two voltage levels must have a peak voltage sufficient to cause a glow discharge to occur in the presence of a collected charge field, and the higher of the two voltage levels must not have a peak voltage sufiicient to cause a glow discharge to occur in the absence of a collected charge cloud or field.
  • AC signal voltages typically, between and 300 volts, depending upon the nature, pressure, and other characteristics of the gas existing between the two glass sheets, the nature, the thickness and the separation of the glass sheets, and the areas of the electrode conductors and their separation from one another.
  • the electrode conductors 64, 67, 68, 69 and 70 the voltage of the electrode conductor 64, glow' discharge signals present on the electrode conductor 54 will be transferred to the electrode conductor 64 from the wide ends of the segments of the electrode conductor 54 to the narrow ends of the next adjacent segments of the electrode conductor 64.
  • the glow discharge signals present on the various segments of the electrode conductors'64 will transferred to the segments of the electrode conductor 54 that are to the right of the corresponding segments of the electrode conductor 64.
  • FIG. 9 presupposes a common electrode conductor 40 opposite the electrode conductors shown in FIG. 9.
  • FIG. 10 show an alternative embodiment of the present invention in which patterned electrodeconductors are arranged on both sheets of glass.
  • the conductors represented in FIG. 10 by light outlines and cross-hatch lines are attached to one sheet of glass and the electrode conductors represented by bold object lines and no cross hatching are mounted on the opposite sheet of glass.
  • the AC'voltages applied to the several electrode conductors on one sheet of glass in FIG. 10 are referenced to the electrode conductors on the other sheet of glass in FIG. 10 rather than to a common electrode conductor.
  • ductors 84 and 80 The high AC voltages that are applied between the electrode conductors 80 and 84 must be in the proper phase to add their peak voltages of opposite polarity to generate a peak voltage in the area where they overlap.
  • the glow discharge will remain in the region between the electrode conductors 80 and 84.
  • the glow discharge will transfer from the position between the electrode conductors. 80 and 84 to the position between the electrode conductors 82 and 84 assuming that the electrode conductors 84 and 86 are maintained at a high AC voltage and the electrode conductor 88 is maintained at a low AC voltage.
  • the electrode conductor 84 has the same voltage as the electrode conductor 86, the glow discharge will not transfer directly from the electrode conductor 88 to the electrode conductor 84 in the example explained above; because, the electrode conductor 80 is rather narrow in the region between the electrode conductor 84 and the electrode conductor 88 and is rather wide in the region between the electrode conductor 88 and the electrode conductor 86. In addition, the electrode conductor 88 is very close to the electrode 86 in the region adjacent the electrode conductor 80. Whereas, the electrode conductor 88 is rather far from the electrode conductor 84 in the region of the electrode conductor 80.
  • the glow discharge can be stepped in the reverse direction. For example, assume that the glow discharge exists between the electrode conductors 80 and 88. A lowering of the voltage of the electrode convoltage of the electrode conductor 88 causes the glow discharge to move to the area between the electrode conductors 82 and 84.
  • FIG. 1 there is shown an arrangement of the electrode conductors similar to FIG. but arranged to transfer a glow discharge along a leg 89 of a shift register 90 and back down another leg 91 of the shift register 90 that is folded over the leg 89.
  • Four ductor 80 accompanied by the raising of the voltage of electrode conductors 92, 93, 94 and 96 are arranged parallel to each other on the outer surface of one of two glass sheets forming the envelope of gas.
  • the electrode conductors 92 and 94 experience the same AC voltage.
  • Electrode conductors 93 and 96 experience the same AC voltage.
  • the electrode conductors 92 and 94 experience different AC voltages than the electrode conductors 93 and 96.
  • An ignition electrode 98 is placed on the other sheet of glass and is always supplied with sufficient AC voltage with respect to the electrode conductor 92 or the electrode conductor 93 to cause a glow discharge to occur in the region between the ignition electrode conductor 98 and the electrode conductor 92 or the electrode conductor 93, no matter what the previous state of this region was.
  • This function is similar to the ignition electrode 36 of FIG. 8; therefore, a glow discharge is always available for transfer to a first intermediate electrode conductor 100.
  • the first intermediate electrode 100 is sometimes maintained at a low AC voltage and sometimes a high AC voltage.
  • the first intermediate electrode conductor 100 When the first intermediate electrode conductor 100 is maintained at a high AC voltage, a glow discharge will transfer from the ignition electrode conductor 98 to the first intermediate conductor 100 along the electrode conductor 92 in the region where the electrode conductors 98 and 100 are closer to each other.
  • the voltage of the electrode conductor 92 is subsequently decreased and the voltage of the electrode conductor 93 is increased, the glow discharge adjacent the first intermediate electrode conductor 100 then transfers from the area where the electrode conductor 92 overlaps the first intermediate electrode conductor 100 to the region where the electrode conductor 93 overlaps the first intermediate electrode conductor 100. Therefore, when the voltages on the electrode conductors 100 and 93 are high, a glow discharge condition is always available between them.
  • a second intermediate electrode conductor 102 is positioned adjacent the first intermediate electrode conductor 100 along the length of the electrode conductor 93.
  • the second intermediate electrode conductor 102 isnormally maintained at a very low AC voltage such that a glow discharge will not ordinarily be transferred from the first intermediate electrode conductor 100 to the second intermediate electrode conductor 102 in the region adjacent the electrode conductor 93.
  • the AC voltage of the second intermediate electrode conductor 102 is raised to a higher AC voltage with respect to the electrode conductor 93. This higher transferred from the first intermediate electrode conductor 100 to the second intermediate electrode 102 while the electrode conductor 93 is maintained at a high electrode AC voltage and the electrode conductor 92 is maintained at a low AC voltage.
  • the second intermediate electrode conductor 102 will then be maintained at a high AC voltage while the voltage on the electrode conductor 93 is reduced and the voltage on the electrode conductor 92 is increased to cause the glow discharge condition to step from the area where the second intermediate electrode conductor 102 overlaps the electrode conductor 93 to the region where the second intermediate electrode conductor 102 overlaps the electrode conductor 92.
  • successive changes of the voltage applied to the electrode conductors 92 and 93 and to the electrode conductors that are on the same glass sheet as the electrode conductors 98, 100 and 102 cause the glow discharge condition to advance along the first leg 89 of the shift register 90 in the same manner as was explained in connection with FIG. 10.
  • the AC voltage on the elec trode conductors '1 12 and 114 is reduced, accompanied by an increase in the AC voltage of the electrode conductor 1 10.
  • the voltage of the electrode conductor 94 remains the same. This causes the glow discharge condition to be transferred to the region between the electrode conductors 1 l and 94.
  • Successive alterations of the AC voltages applied to the various electrode conductors similarly causes the glow discharge condition to migrate to the left along the leg 91 of the shift register 90 until it reaches the region between a transfer electrode conductor'120 and the electrode conductor 96.
  • the glow discharge condition can then be transferred along the electrode conductor 120 to another electrode conductor 122 of an adjacent shift register very similar to the shift register 90.
  • the electrode conductor 122 would correspond to the electrode conductor 92 of the shift register 90.
  • the adjacent shift register would then have no need of the electrode conductors 98, 100, and 102.
  • a first shift register 130 is shown, very much like the shift register of FIG. 10.
  • An ignition or firing electrode conductor 132 is positioned on one of the glass sheets.
  • a companion ignition electrode conductor 134 is positioned on the opposite glass sheet.
  • the electrode conductors 132' and 134 have a plurality of ignition pads 135 which are arranged in an arbitrary, predetermined pattern adjacent the shift register 130.
  • a glow discharge is ignited at all of the pads 135 by a high AC voltage applied between the electrode conductors 132 and 134. This high AC voltage is then reduced to the normal maintaining voltage.
  • the voltage of an electrode conductor 136 of the shift register 130 is then increased and the voltage of a parallel electrode conductor 138 of the shift register 130 is decreased at the same time that a high AC voltage is maintained on a plurality of electrode conductors 140 that run perpendicular to the electrode conductors 136 and 138.
  • the voltage between the ignition electrode conductors 132 and 134 is sharply reduced so that the glow discharge conditions that had existed on the pads. 135 between the electrode conductors 132 and 134 are transferred to the regions between the electrode conductor 136 and the electrode conductors 140.
  • a glow discharge will be transferred only to those regions of the shift register 130 which are adjacent to the selectively arranged ignition pads 135 of the electrode conductors 132 and 134.
  • the ignition pads of the electrode conductors 132 and 134 would be arranged in accordance with the locations of dots necessary to form the alphanumeric or other characters of the display.
  • the glow discharge conditions existing on the shift register 130 can then be transferred to the right along the shift register 130 in the manner that is described in connection with the shift register of FIG. 10.
  • a glow discharge condition When a glow discharge condition reaches the area designated by the reference number 142, it can be transferred to an orthogonal shift register 144 at such time as the adjacent region referred to by the reference number 146 is experiencing a high AC voltage.
  • This glow discharge condition can then be carried along the shift register 144 in the manner described in conjunction with FIG.
  • FIG. 13 an entire encoding and display system is shown schematically using many repetitions of the folded shift register disclosed in FIG.
  • the shift register 144 from FIG. l2i is arranged perpendicular .to a plurality of shift registers -A, 130-B, 130-C, etc., similar to the shift register 130 of FIG. l2.
  • a plurality of ignition electrode conductors 132-A, 132-B, 132-C, etc., are arranged similar to the ignition electrode conductors 132 and 134 of FIG. 12.
  • the dash letters are used in FIG. 13 to represent the alphanumeric character associated with each of the ignition electrode conductors 132 and each of the shift registers 130.
  • a high AC voltage is appliedto the ignition electrode conductor 132A.
  • the glow discharge conditions generated at the ignition pads of the electrode conductor 132-A are then transferred to the shift register 130-A as explained in connection with FIG. 12.
  • the glow discharge conditions then existing in the shift register 130-A are transferred to the right in FIG. 13 and onto the orthogonal shift register 144 which carries the glow discharge conditions to the display screen 150.
  • the glow discharge conditions are carried from segment to segment of the display screen 150 as explained in connection with FIG. 11; Naturally, the glow discharges in the display screen 150 are advanced rapidly until they are in position for an intelligible display, at which time the advance is stopped momentarily to permit visual perception of the display.
  • next character to be displayed is the letter B
  • a high AC voltage is applied to the ignition electrode conductor 132-B.
  • These glow discharge conditions are then transferred to the shift register 130-8 and are carried along to the shift register 144.
  • the ignition electrode conductor 132-8 extends further to the right in FIG. 13 than does the ignition electrode conductor l32-A. This is to accommodate the displacement of the shift registers 130 along the length of the shift register 144.
  • Three complete shift register elements along the shift register 144 are located between each adjacent shift register 130. Therefore, each ignition electrode conductor 132 for each successive alphanumeric character that is placed further away from the display panel 150 should also be placed threeshift-register-elements to the right of the adjacent ignition electrode conductors 132.
  • Each alphanumeric character to be displayed may require precisely the same number of shift register cycles to reach the same spot on the display screen 150 from the instant of ignition at its associated ignition electrode conductor 132.
  • An apparatus wherein a plasma discharge occurs in a gas-filled, dielectric envelope by applying an AC. voltage between two electrodes on opposite sides of the envelope, characterized by one of the electrodes being tapered with the plasma discharge being applied first near the narrow end of the tapered electrode and progressing in steps toward the wide end on each halfcycle of the applied AC. voltage which causes a greater capacitive coupling through the dielectric envelope at wider portions of the tapered electrode causingdischarge to preferentially occur near the wide end of the electrode.
  • each coversheet having conductors thereon with the conductors being located opposite one another across the gas-filled space, so that ionization of the gas takes place when a predetermined voltage exists across the space between the conductors causing the gas to glow, an improvement including:
  • the dielectric envelope being of a size capable of supporting a plurality of simultaneous glow discharges; means for applying voltage to the conductors; and the shape of the gas filled envelope relative to the shape of at least one of the conductors being such that the area of the gas filled space beneath the conductor varies in a predetermined manner along at least one conductor, so that the application of voltages of different magnitude by the voltage applying means causes discharges to take place in different portions of the envelope corresponding .to a predetermined relationship of applied voltage to the gas filled area beneath the electrodes. 3.
  • An improved apparatus for display or memory having a first and second dielectric coversheet spaced apart and sealed to form an envelope with a gas therein and at least one conductor on the first coversheet outside of the envelope and at least two conductors on the second coversheet outside of the envelope, means for selectively initiating a glow discharge in the gas between the conductor on the first coversheet and one of the conductors on the second coversheet, and means for continuously applying AC voltage between the conductor on the first coversheet and the conductors on the second coversheet, the AC voltage being of insufficient magnitude to initiate a glow discharge but of sufficient magnitude to sustain a glow discharge, wherein theimprovement comprises:
  • An improved apparatus for display or memory having first and second dielectric coversheets spaced apart and sealed to form an envelope with a gas'therein and at least one conductor on the first coversheet outside of the envelope and at least a first conductor and a second conductor on the second coversheet outside of the envelope, means for selectively initiating a glow discharge in the gas between the conductor on the first coversheet and the first conductor on the second coversheet, and means for continuously applying an AC voltage between the conductor on the first coversheet and the first and second conductors on the second coversheet, the AC voltage being of insufficient magnitude to initiate a glow discharge but of sufficient magnitude to sustain a glow discharge, wherein the improvement comprises:
  • An apparatus wherein the 15. An apparatus according to claim 14 wherein the second conductor is one of a plurality of electricallyconnected, generally tapered electrode segments arranged in a line on the second coversheet;- and wherein the first conductor is one of a plurality of electrically-connected, generally tapered electrode segments arranged in a line on the second coversheet.
  • An apparatus according to claim 15 wherein the wide ends of the taperedelectrode segments of the first conductor are positioned adjacent but not touching the reducing means comprises means for holding constant the AC voltage applied to the first conductor on the second coversheet and means for increasing the AC voltage applied to the second conductor on the second 7.
  • An apparatus further com- 1 prising'a third conductor on the second coversheet voltage applied to the first conductor on the second of the AC voltages to cause the instantaneous voltage applied to the second conductor on the second coversheet to rise sooner than the instantaneous voltage, applied to the first conductor on the second coversheet.
  • varying means comprises means for holding steady the AC voltage applied to the first conductoron the second coversheet and means for advancing the AC voltage applied to the second conductor on the second coversheet.
  • varying means comprises means for holding steady the AC voltage applied to the second conductor on the second coversheet and means for retarding the AC voltage applied to the first conductor on the second coversheet.
  • varying means comprises means for retarding the AC voltage applied to the first conductor on the second coversheet andmeans for advancing the AC voltage applied to the second conductor on the second coversheet.
  • the third conductor being tapered, having a wide end and a narrow end, with the narrow end of the third conductor positioned adjacent to but not touching the one tapered segment;
  • thethird conductor being one of a plurality of electrically connected, generally tapered electrode segments arranged in a line perpendicular to the lines of the first and second conductors.
  • An apparatus further comprising a plurality of fourth tapered, electrically-connected conductors on the second coversheet arranged in a line parallel with the line of thethird conductor; and i the fourth conductors being electrically connected to one of the other conductors on the second coversheet.
  • a shift register for moving data bits generally in a line comprising: v
  • a shift register according to claim 19 further comprising a second shift register arranged generally in a second line intersecting the line of the first shift register and arranged so that a bit-representing plasma discharge progressing along the line on the first shift register is transferred to the second shift register and progresses along the secondline on the second shift register.
  • a shift register according to claim 19 further comprising:
  • a display device comprising:
  • a plurality of shift registers comprising conductors on the outside of the envelope for moving data-bitrepresenting plasma discharges generally along substantially parallel lines;
  • a manifold shift register arranged along a line intersecting the parallel lines for receiving plasma discharges from the shift registers and for moving the plasma discharges generally along the intersecting line;
  • a method according to claim 24 wherein the causing step comprises reducing the magnitude of the AC voltage applied between the first pair of conductors with respect to the AC voltage applied between the second pair of conductors so that the magnitude of the AC voltage between the first pair of conductors is less than the magnitude of the AC voltage between the second pair of conductors but still sufficient to maintain a memory condition.
  • a method according to claim- 25 wherein the reducing is accomplished by holding constant the AC voltage applied between the first pair of conductors and increasing the AC voltage applied between the second pair of conductors.
  • a method according to claim 24 wherein the causing step comprises varying the phase of the AC voltages to cause the instantaneous voltage applied between the second pair of conductors to rise sooner than the instantaneous voltage applied between the first pair of conductors.
  • the improved method comprises:
  • a method according to claim 29 further comprising the step of changing the AC voltages applied to the first and second conductors to cause the instantaneous voltagedifference between the second conductor and at least one of the conductors on the second coversheet to reach an instantaneous magnitude sufficient to sustain a glow discharge in the gas sooner than the instantaneous AC voltage applied between the first conductor and the conductors on the second coversheet reaches an instantaneous magnitude sufficient to sustain a glow discharge in the gas, thereby moving the low discharge condition from between the first and ourth conductors to between the second and fourth conductors.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Plasma Technology (AREA)
US49436A 1970-06-24 1970-06-24 Method and apparatus for memory and display Expired - Lifetime US3704389A (en)

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US (1) US3704389A (enrdf_load_stackoverflow)
BE (1) BE768870A (enrdf_load_stackoverflow)
CA (1) CA931253A (enrdf_load_stackoverflow)
DE (1) DE2130706A1 (enrdf_load_stackoverflow)
FR (1) FR2099839A5 (enrdf_load_stackoverflow)
NL (1) NL7108652A (enrdf_load_stackoverflow)

Cited By (11)

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DE2713361A1 (de) * 1976-03-29 1977-10-13 Fujitsu Ltd Verfahren zum verschieben eines entladungspunktes
DE2729659A1 (de) * 1976-07-02 1978-01-05 Fujitsu Ltd Gasentladungsplatte
DE2731008A1 (de) * 1976-07-09 1978-01-12 Fujitsu Ltd Gasentladungs-anzeigefeld
DE2741750A1 (de) * 1976-09-16 1978-03-23 Fujitsu Ltd Selbstverschiebungs-gasentladungspaneel
DE2754251A1 (de) * 1976-12-06 1978-06-08 Fujitsu Ltd Gasentladungstafel
WO1984001658A1 (en) * 1982-10-18 1984-04-26 Univ Leland Stanford Junior Bubble display and memory device
FR2635900A1 (fr) * 1988-08-30 1990-03-02 Thomson Csf Panneau a plasma a adressabilite accrue
EP0376829A1 (fr) * 1988-12-30 1990-07-04 Thomson Tubes Electroniques Dispositif d'affichage par panneau à plasma de faible résolution
FR2673314A1 (fr) * 1991-02-25 1992-08-28 Thomson Tubes Electroniques Dispositif d'affichage a zones de decharge ajustables.
US5315312A (en) * 1991-05-06 1994-05-24 Copytele, Inc. Electrophoretic display panel with tapered grid insulators and associated methods
US20100073350A1 (en) * 2008-09-24 2010-03-25 Apple Inc. Display with reduced parasitic effects

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3795908A (en) * 1972-06-13 1974-03-05 Ibm Gas panel with multi-directional shifting arrangement

Citations (4)

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US3499167A (en) * 1967-11-24 1970-03-03 Owens Illinois Inc Gas discharge display memory device and method of operating
US3500121A (en) * 1968-02-15 1970-03-10 Gen Time Corp Electronic counting or timekeeping system using glow discharge tube without permanent anode
US3509408A (en) * 1967-12-13 1970-04-28 Burroughs Corp Display panel with separate signal and sustainer electrodes
US3513327A (en) * 1968-01-19 1970-05-19 Owens Illinois Inc Low impedance pulse generator

Patent Citations (4)

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Publication number Priority date Publication date Assignee Title
US3499167A (en) * 1967-11-24 1970-03-03 Owens Illinois Inc Gas discharge display memory device and method of operating
US3509408A (en) * 1967-12-13 1970-04-28 Burroughs Corp Display panel with separate signal and sustainer electrodes
US3513327A (en) * 1968-01-19 1970-05-19 Owens Illinois Inc Low impedance pulse generator
US3500121A (en) * 1968-02-15 1970-03-10 Gen Time Corp Electronic counting or timekeeping system using glow discharge tube without permanent anode

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2713361A1 (de) * 1976-03-29 1977-10-13 Fujitsu Ltd Verfahren zum verschieben eines entladungspunktes
DE2729659A1 (de) * 1976-07-02 1978-01-05 Fujitsu Ltd Gasentladungsplatte
DE2731008A1 (de) * 1976-07-09 1978-01-12 Fujitsu Ltd Gasentladungs-anzeigefeld
DE2741750A1 (de) * 1976-09-16 1978-03-23 Fujitsu Ltd Selbstverschiebungs-gasentladungspaneel
DE2754251A1 (de) * 1976-12-06 1978-06-08 Fujitsu Ltd Gasentladungstafel
US4471469A (en) * 1982-06-21 1984-09-11 The Board Of Trustees Of The Leland Stanford Junior University Negative resistance bubble memory and display device
WO1984001658A1 (en) * 1982-10-18 1984-04-26 Univ Leland Stanford Junior Bubble display and memory device
EP0361992A1 (fr) * 1988-08-30 1990-04-04 Thomson-Csf Panneau à plasma à adressabilité accrue
FR2635900A1 (fr) * 1988-08-30 1990-03-02 Thomson Csf Panneau a plasma a adressabilite accrue
US5086257A (en) * 1988-08-30 1992-02-04 Thomson-Csf Plasma panel with increased addressability
EP0376829A1 (fr) * 1988-12-30 1990-07-04 Thomson Tubes Electroniques Dispositif d'affichage par panneau à plasma de faible résolution
FR2641413A1 (fr) * 1988-12-30 1990-07-06 Thomson Tubes Electroniques Dispositif d'affichage par panneau a plasma de faible resolution
FR2673314A1 (fr) * 1991-02-25 1992-08-28 Thomson Tubes Electroniques Dispositif d'affichage a zones de decharge ajustables.
US5315312A (en) * 1991-05-06 1994-05-24 Copytele, Inc. Electrophoretic display panel with tapered grid insulators and associated methods
US20100073350A1 (en) * 2008-09-24 2010-03-25 Apple Inc. Display with reduced parasitic effects
US8384634B2 (en) * 2008-09-24 2013-02-26 Apple Inc. Display with reduced parasitic effects

Also Published As

Publication number Publication date
CA931253A (en) 1973-07-31
FR2099839A5 (enrdf_load_stackoverflow) 1972-03-17
NL7108652A (enrdf_load_stackoverflow) 1971-12-28
DE2130706A1 (de) 1971-12-30
BE768870A (fr) 1971-12-22

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