US3749969A

US3749969A - Gas discharge display apparatus

Info

Publication number: US3749969A
Application number: US00112293A
Authority: US
Inventors: H Hori; S Miyashiro; K Ogawa
Original assignee: Tokyo Shibaura Electric Co Ltd
Current assignee: Toshiba Corp
Priority date: 1970-02-05
Filing date: 1971-02-03
Publication date: 1973-07-31
Anticipated expiration: 1990-07-31
Also published as: JPS491064B1; CA935862A; DE2105496A1; NL7101528A; GB1336232A; FR2095476A5; DE2105496B2

Abstract

A gas disharge display apparatus including a plasma constricting member disposd between a cathode electrode and an anode electrode, said plasma constricting member having a plurality of plasma pinching holes and being associated with a scanning device for selecting one of said holes so as to concentrate said plasma in the selected hole.

Description

United States Patent [191 Miyashiro et al. ,iy 31, 11973 4] GAS DISCHARGE DISPLAY APPARATUS [56] neterenees Cited [75] Inventors: Shoichi Miyashiro; Kazuyuki UNITED STATES PATENTS Ogawa, both of h m 3,553,458 1/1971 Schagen 315/169 R x Hiroo 1161-1, Kawasaki-8hr, 21,273 1/1912 Kupsky 315/169 R x n of Ja an 2,749,462 6/1956 Kenty et al. 315/225 x Assignee: Tokyo Shibaura Electric Co.

td-5 Kawasak hiv Japan, 3.

Filed: Feb. 3, 1971 Appl. No.: 112,293

Foreign Application Priority Data Feb. 5, 1970 Japan 45/9540 US. Cl. 315/169 TV, 313/201, 313/220 Int. Cl. H05]: 37/00 Field of Search 313/201, 220;

315/169 R, 169 TV Primary ExaminerRoy Lake Assistant Examiner-Lawrence J. Dahl Att0rney-Flynn & Frishauf [5 7 ABSTRACT A gas disharge display apparatus including a plasma constricting memberd isposed between a cathode electrode and an anode electrode, said plasma constricting member having a plurality of plasma pinching holes and being associated with a scanning device for selecting one of said holes so as to concentrate said plasma in the selected hole.

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10 or 1 SCANNING CIRCUIT GAS DISCHARGE DISPLAY APPARATUS This invention relates to an information display apparatus and more particularly to a gas discharge display apparatus. It is well known that a light appears from a plasma generated by a glow discharge resulting from impression of high voltage between a cathode and anode. Since the discharge light is given by so disposing the cathode and anode as to face each other in a flat envelope, there have recently been made various developments to obtain a flatter display tube than a plain cathode-ray tube.

For example, the self scan panel display device recently announced by the Burroughs Co. of the United States had divided cathode elements and causes a glow discharge to be shifted, as in a decatron, from one to another of numerous divided cathode elements so as to carry out a numeric display. Also Th. J. de Boer (ninth National Symposium on Information Display, 1968) and B. M. Arora et al. (eighth National Symposium on Information Display, 1967) respectively announce a discharge display device. The device consists of two groups of conductor lines arranged at right angles in the form of a matrix with a prescribed gap allowed therebetween, namely, a group of cathode conductor lines and a group of anode conductor lines. Light is given forth by causing a glow discharge to be presented at the intersection of one selected cathode conductor line and one selected anode conductor line when there is impressed voltage therebetween. Since said glow discharge display is based on a glow discharge light produced at the respective cross points of the matrix, there cannot be obtained at said points a very much large discharge current and in consequence a glow discharge light in sufficient amount and intensity. Further, the glow discharge prominently varies with, for example, the inter-electrode gap, and the form of the electrode, so that any of the prior art discharge display devices having the aforementioned matrix arrangement of conductor lines has the drawback that the light emitting property presents variations and the light point cannot be shifted quickly.

It is accordingly the object of the present invention to provide a gas discharge display apparatus capable of exhibiting a sufficiently intense light and causing a light point to be quickly shifted always under a stable condition wherein there is disposed in a discharge passage across the cathode and anode plasma pinching or constricting member perforated with a plurality of plasma pinching or constricting holes and a plasma derived from a glow discharge near the cathode is selectively concentrated in one of the plasma pinching or constricting holes thereby to obtain a light of high intensity.

The present invention can be more fully understood from the following detailed description when taken in connection with the accompanying drawings, in which:

FIG. I is a sectional view of a discharge tube included in a gas discharge display apparatus according to an embodiment of the present invention;

FIG. 2 is a sectional view on line II-II of FIG. I as viewed in the direction of the arrows, also schematically showing a scanning device connected to a discharge tube;

FIG. 3 illustrates the principal whereby the pinched plasma formed by the present invention gives forth a light of high intensity;

FIG. 4 presents a plasma constricting hole according to the theory of FIG. 3;

FIG. 5 is a sectional view of a modification of the tube shown in FIG. I;

FIG. 6 is a sectional view of a gas discharge display apparatus according to another embodiment of the invention;

FIG. '7 is a-sectional view of a discharge tube connected to the scanning device on line VIIVII of FIG. 6 as viewed in the direction of the arrows;

FIG. 3 is a sectional view of another plasma constricting member according to the invention;

FIG. 9 is a sectional view of still another plasma constricting member according to the invention;

FIG. III is a sectional view of another display tube according to the invention;

FIG. II is a sectional view on line XI-XI of FIG. 10;

FIG. I2 shows the circuit arrangement of a gas discharge display apparatus fitted with a scanning-device for scanning a discharge point while shifting it through a plurality of plasma constricting holes;

FIGS. I3 and M indicate the circuit arrangements of other scanning devices used in the gas discharge display apparatus of the invention;

FIG. I5 illustrates the connection between the plasma constricting member and scanning device of FIG. Id;

FIG. III presents the wave form of signals showing the operation of the scanning device of FIG. 14;

FIGS. I7 to ZIP are the circuit arrangements of still other scanning devices used in the gas discharge display apparatus of the invention, diagrams showing the connection between the plasma constricting member and scanning device, and charts of signal wave forms indicating the operation of the scanning device;

FIG. 21 illustrates a system of scanning a plasma constricting member for a two-dimensional display;

FIG. 22 shows the wave form of signals illustrating the operation of the plasma constricting member of FIG. 21;

FIG. 23 presents anothep system of scanning a plasma constricting member for a two-dimensional dis- P y;

FIGS. 2d and 25 are the diagrams of a circuit for scanning the plasma constricting member of FIG. 21; and

FIG. 26 schematically sets forth the construction of a display tube having a cold cathode according to still another embodiment of the invention.

Throughout the Figures of the drawings, the same parts are denoted by the same numerals. While the gas discharge display apparatus of the present invention can provide a oneand two-dimensional display of information, there is first described an embodiment associated with a one-dimensional display.

In FIGS. I and 2, the front panel 2 of a sealed vessel I is made of a transparent material, for example, glass. The vessel I is first evacuated through an evacuating port 3 by evacuating means (not shown) to high vacuum and then filled with proper gas, for example, he- Iium gas of 4 mmI-Ig. The sealing gas may consist of at least one of, for example, helium, neon, argon, hydrogen and nitrogen commonly used in a discharge tube. The pressure at which such gas is introduced has only to be defined within the range of 1 to scores of torr. Of course, the sealing gas may contain, if necessary, mercury vapor.

On the substantially entire inner surface of the front panel 2 is deposited an anode 4 consisting of a transparent fil. The anode 4 is connected through a stabilization resistor 6 to the positive side of a high voltage D.C. side, the negative side of which is grounded. On the inner surface of the vessel 1 facing that of the front panel 2 is disposed cathode 7 having a substantially the same area as the anode 4 except for the cavity 8. In the cavity 8 is placed a filament 9 for heating cathode 7. The filament is heated by a filament power source 10. One end of the filament 9 connected to the negative side of said source 10 is grounded together with the cathode 7.

Near the anode 4 of the vessel 1 is disposed, as illustrated in FIG. 1, an insulating material, for example, ceramic plasma constricting member 11 substantially parallel with the anode 4, with the periphery of said member 11 fitted to the inner wall of the vessel 1. The plasma constricting member 1 l is bored with a plurality of plasma constricting holes 12 linearly arranged at an equal interval lengthwise of said member 11. The inner wall of the hole 12 is, for example, electroplated with a conductor film 13, which is connected to the changeover or switching output terminal of a scanning circuit 14 and further selectively connected through a stabilization resistor 15 to the positive side of a switching power source 16 having a slightly lower voltage than the high voltage power source 5, the negative side of said power source 16 being grounded. There will be later described in greater detail the arrangement and operation of said scanning circuit 14.

There will now be described the operation of the gas discharge display apparatus. The cathode 7 is heated by the filament 9 to emit large amounts of electrons, thereby forming a plasma region 17 indicated by the dotted line of FIG. 1. If, at this point, the anode 4 is supplied with high voltage, for example, positive voltage of 200 V, then the electrons emitted from the cathode 7 are carried to the anode 4 to present a discharge. Since, however, there is interposed the plasma constricting member 11 between the cathode 7 and anode 4, the electron from the cathode 7 reaches the anode 4 through any of the holes 12 formed in the plasma constricting member 11. When the presecribed one of the electrodes 13 is momentarily impressed with positive voltage by operating the scanning circuit 14, then there occurs a discharge across the cathode 7 and anode 4 through the hole 12 momentarily supplied with said positive voltage. Said discharge continues even after the switching voltage is cut off. Where another electrode 13 is selectively supplied with voltage by the scanning circuit 14, the resulting discharge will be presented through the hole 12 provided with said electrode 13, causing the preceding discharge to cease to appear. Thus, one of the characteristics of the embodiment of FIG. 1 is that it can easily display a sort of memory function. If the desired plasma constricting electrodes are selectively supplied with changeover pulse voltage in turn at a preset interval by the scanning circuit 14, then there will appear a one-dimensional display formed by the pinched plasma 18.

As apparent from the aforesaid embodiment, the present invention consists in disposing a plasma constricting member bored with plasma constricting holes between the cathode and anode and causing a discharge to be produced through said holes, thereby giving forth an intense light near said holes. Now let us consider the function of a gas discharge display apparatus according to the present invention to generate a strong light. The solid line of FIG. 3 is a fractional schematic illustration of a discharge region extending from the plasma region 17 of FIG. 1 to the plasma constricting hole 12. Line BB is supposed to represent the central axis of the hole 12. For better understanding of the present apparatus, solid line A may be deemed to denote the shape of a discharge tube and axis B-B that said tube. Electron streams are assumed to flow along axis 8-8 from the broader to the narrow diameter of the discharge tube, that is, from the left to the right of FIG. 3. There will now be analyzed the generation of a light in the hole 12 of FIG. 1 from the view point of the different tube diameters at points C and D in axis BB of the discharge tube in a plane intersecting said axis 8-8 at right angles as well as from the view point of the means free path of electrons at said points. Experimental work by the present inventors shows that with the maximum difference in the tube diameter designated as Ar and the mean free path of electrons through said points as he, when there was established a relationship of Ar lte between both factors, then there arose an intense light. In case of Ar )te, the total amount of electrons absorbed by impingement on the inner wall of the tube due to reduction in its diameter was compensated by increased amounts of electrons generated be elevated collision ionization occurring between electrons and the gas atoms, so tat the electic field in that region varied vary little. Conversely in case of Ar ).e, there appeared less collision ionization between electrons and the gas atoms leading, as naturally expected to a decline in the number of electrons, or current. Since current practically has to be kept constant, a decrease in current should be supplemented by an increase in the number of electrons per unit time effected by acceleration of electrons. This means that there should arise a rapid growth of an electric field. Obviously, such a sharp increase in he electric field is the very reason why there is generated a strong light in the plasma constricting hole according to the present invention. In a plane including point C of FIG. 3, with gas pressure in the discharge tube denoted as P and the mean free path of electrons as he variation in the tube diameter may be expressed as Ar,, and in case the gas pressure is increased to P, and the mean free path of electrons to ke then the tube diameter will only have to be varied to Ar To obtain a relationship of Ar lte at point C, therefore, gas pressure in the discharge tube should be changed In constrast at point D, if gas pressure in the discharge tube indicates P,, the tube diameter will have a broad variation of Ar, with respect to the mean free path he, of electrons. Accordingly at that point of the discharge tube where its diameter prominently varies, for example, at point D, it is possible easily to satisfy the relation of Ar ).e without changing gas pressure and in oncsequence to produce an intense light.

There has been described with reference to FIG. 3 the requisite conditions for constructing a gas discharge display apparatus according to the present invention so as to increase an electric field prevailing at an arbitrary point in discharge passage. Said conditions will be further detailed by reference to FIG. 4 showing a discharge tube whose diameter sharply decreases on line D-D. Let the cross sectional area of the tube including line D-D be designated as S, the random electron-current density of a plasma in said area as .I and the total current passing through the DD section of the tube as I. In case of S-J I, there will not appear a prominent change in the electric field in the DD section, through the aforesaid construction conditions may be fully met. In constrast, where there is introduced sufficient current to realize 8'] 1, then there will arise an electric double layer, leading to the rapid growth of an electric field. Since such electric field genertes concentrated accelerated electron beams due to the unique property of the electric double layer, there are often obtained the following particularly useful advantages.

a. Since electrons are carried away toward the anode, that is, to the right side of FIG. 4, a plane of equivalent potential projects toward the cathode to constitute a sort of focusing lens with respect to the electrons.

b. Since electrons are freely accelerated in the electric double layer they are conducted through the DD section with relatively uniform high energy to form a high density plasma.

When electron temperature was measured by inserting a prove electrode in said high density plasma, there was indicated a value of 30 to 55 eV in, for example, hydrogen atmosphere. In said region there appeared such an intense light as could hardly be well accounted for by the ordinary positive colum theory.

FIG. 5 shows a modification of the cathode used in the embodiment of FIG. 1. While this embodiment uses an indirectly heated cathode, that of FIG. 5 uses a filament coated with a thermion emitting layer. The latter embodiment causes the filament to be uniformly heated. The same parts of FIG. 5 as those of FIG. 1 are denoted by the same numerals and description thereof is omitted.

FIGS. 6 and 7 jointly illustrate another embodiment of the present invention. According to this embodiment, the plasma constricting member 11 consists of an opaque material, for example, an insulation substrate 22 made of black glass which is perforated with a plurality of holes 21 arranged at an equal interval lengthwise of said member 11. To the front surface of the insulator substrate 22 is tightly fitted a transparent insulation plate 23, for example, a glass plate, so as to close up the opening of the holes 21. On that part of the surface of the glass plate 23 which faces the holes 21 are mounted a plurality of transparent conductor layers 24 each as an anode. As in FIG. 1, the anodes 24 are selectively impressed with anode voltage by the scanning circuit 14. In the embodiment of FIGS. 6 and 7, the anodes 24 are directly connected to the scanning circuit 14, so that the discharge tube has a simpler arrangement than, but performs the same operation as, that of FIG. 1.

FIGS. 8 and 9 present plasma constricting members 11 according to still other embodiments of the present invention. The member 11 of FIG. 8 has a plurality of conductive anode cylinders disposed in the holes 12 formed in the opaque insulation substrate 22, said cylinder 25 having substantially the same outer diameter of the holes 12. On the inner wall of the cylinder 25 is disposed a thin fluorescent layer 26 in contact with a transparent glass plate 23. It is possible to insert a separately fabricated anode cylinder 25 into the hole 12. Alternatively, there may be directly evaporated or plated a conductor layer on the inner wall of the hole 12. According to the embodiment of FIG. 8, a plasma region 17 formed by electrons emitted from a cathode (not shown) presents a constricted plasma 18 in the hole 12 when any of the anode cylinders 25 is selectively impressed with anode voltage. In this embodiment, not only the strong light generated from the constricted plasma 18 itself, but also a light produced by the electrons of the constricted plasma 18 impinging on the fluorescent layer 26 is conducted to the opposite side of the glass plate 23 through said fluorescent layer 26. If, in this embodiment, there are used small amounts of mercury vapor as a seal gas there will be contained large amounts of ultraviolet rays in the discharge light, thereby giving forth an exremely bright fluorescent light clue to the fluorescent layer 26 being strongly excited by said ultraviolet rays. If there is used a fluorescent layer particularly having a proper time of residual light there will be obtained a continuous display without flicker. Further, selection of the material of the fluorescent layer 26 permits the generation of such a light or display as bears any desired color or colors.

The embodiment of FIG. 9 uses a funnel-type anode cylinder 27 in place of the anode cylinder 25 of the plasma constricting member of FIG. 8. The large diameter opening of the funnel-type cylinder contacts the glass plate 23. On said glass plate 23 is deposited a fluorescent layer 26 in a manner to close up said opening. The embodiment of FIG. 9 permits still larger amounts of light to be produced because the fluorescent layer 26 is allowed to have a broader area than in FIG. 8.

According to all the foregoing embodiments, the plasma constricting holes 12 are linearly arranged in the plasma constricting member 11 so as to obtain a one-dimensional display. However, the present invention further permits said holes 12 to be arranged in the form of a matrix so as to make a two-dimensional display.

FIGS. 10 and 11 jointly indicate a two-dimensional display arrangement according to still another embodiment of the present invention. On the inner surface of the transparent front panel 2 of a sealed vessel 1 is formed a fluorescent layer 30. On the surface of the fluorescent layer 36 are arranged a plurality of anode plates 31 in the matrix form at an equal interval all over the panel 2. From each anode plate 31 are drawn out

terminals

32 and 33 lengthwise and crosswise. The terminal 32 is supplied with output from a horizontal scanning circuit 34 and the terminal 33 with output from a vertical scanning circuit 35. Said fluorescent layer 30 is provided only where required, and it is possible to form the anode plates 31 alone on the inner surface of the front panel 2. All over that inner wall of the sealed vessel 1 which faces the front panel 2 is disposed a cathode 36 whose terminals 37 are connected to a power source (not shown) to be supplied with voltage. Between the fluorescent layer 30 and cathode 36 is provided an insulation substrate 22 close to and parallel with the fluorescent layer 30. That side of the insulation substrate 22 which faces said plurality of anode plates 31 is bored with plasma constricting holes 12 each fitted with an anode cylinder 25. On that side of the insulation substrate 22 which faces the anode plates 31 are mounted conductor layers 36 to supply the anode cylinders 25 with voltage. Said conductor layers 38 are impressed through terminals 39 with voltage equal to or slightly lower than that of the anode plates 31 by the horizontal and vertical circuits 34 and 35. If

both circuits 34 and 35 are operated to cause a constricted plasma to be selectively generated in any of the holes 12, there will be concentrated a discharge from the plasma region toward the anode plate 31 located at a point where voltages from the circuits 34 and 35 are jointly supplied. As a result, there occurs constricted plasma 18 in the hole 12 corresponding to said anode plate 31, generating an intense light. Also in the embodiment of FIGS. 10 and 11, seal of mercury vapor in the discharge tube permits a more intense light to be produced from the fluorescent layer 32 due to emission of ultraviolet rays. If output voltages from the horizontal and vertical circuits 34 and 35 are changed over from one anode plate to another, then there will be obtained a two-dimensional display on the front panel 2 due to the generation of light in the plasma constricting member 11. Further, the embodiment of FIGS. 10 and 11 can of course permit a display of gray scales by modulating discharge current through adjustment of impedance in the anode circuit connected to the anode plate 31 or by varying a period of discharge. If the fluorescent layer 30 is coated at separate places with fluorescent materials displaying three primary colors to give forth lights of the corresponding colors, then it will be possible to carry out a color display with a higher degree of resolution.

FIG. 12 illustrates the concrete scanning circuit 14 of FIG. 1 used in a one-dimensional display. Between the base and emitter of each transistor 40 are connected the secondary output terminals of each pulse transformer 41. The emitter of each transistor 40 is connected to the positive terminal of a power source 16 through a common resistor 15. The collector of the transistor 40 is connected to the corresponding output terminal 42 of the scanning circuit 14, and grounded through a resistor 43. Said output tenninal 42 is connected to the conductor layer 13 of FIG. 1. The pulse transformers 41 are successively impressed on the input side with signals having the indicated wave form. Let it be assumed that there is formed a constricted plasma 18 in the plasma constricting hole 12 in which there is disposed a conductor layer 13 connected to the output terminal 421 of said scanning circuit 14, and a transistor 402 is conducted by supply of pulse P, causing the output terminal 422 of said circuit 14 to be momentarily impressed with voltage from the power source 16. Then the conductor layer 13 connected to said output terminal 422 is supplied with voltage, giving rise to a discharge across said conductor layer 13 and cathode 7. This causes impedance therebetween to be momentarily decreased and the constricted plasma on the conductor layer 13 connected to the output terminal 421 to pass through the hole 12 facing the conductor layer 13 associated with the output terminal 422. It has been found that said discharge is very rapidly shifted from one conductor layer to another. The embodiment of FIG. 12 operated very satisfactorily when the power source 5 was set at 200 volts, resistor 6 at 20 kiloohms, power source 16 at 100 to 200 volts and resistor at 5 kiloohms.

In the embodiment of FIG. 12, there was impressed pulse voltage through the pulse transformer 41. However, if, as shown in FIG. 13, the emitter of the transistors 40 is grounded and the base thereof is successively supplied with negative pulses P, to turn them on, it will be possible to cause a discharge to be shifted in the same manner as in the preceding case. In the case of FIGS. 12 and 13, the discharge light is dim while there are present pulses P, and P,,, so that the pulse width should be reduced as much as possible to obtain a bright display.

FIGS. 14 to 16 show other scanning systems according to the present invention for a one-dimensional display. Throughout the figures, the collectors of the transistors 40 are connected through resistors 44 to the positive terminal of a switching power source 16 of, for example, 150 volts and directly connected to a terminal 42 contacting the conductor layer 13, and the emitters of said transistors 40 are jointly grounded. The negative terminal of the power source 16 is also grounded.

The

terminals

421, 422, 423 and 424 of FIG. 14 are connected to the conductor layers 13 formed in the plasma constricting members 11 as shown in FIG. 15. Let it be assumed that the conductor layers 131, 132, 133 provided on the inner surface of the respective plasma constricting holes 12 are arranged in turn starting with one end of said member 11. Then the terminal 421 of FIG. 14 is connected to the conductor layer 131, and the terminals 422 to 424 to the conductor layers 132 to 134. In said member 11, the conductor layer 132 is connected to other conductor layers 135 and 138 with intervening two units omitted. Similary the conductor layer 133 is connected to those 136 and 139 and the conductor layer 134 to those 137 and 140.

Let it be assumed that there is present a constricted plasma 18 on the conductor layer 131. Then the cut-off of the transistor 402 by impressing voltage on a terminal 452 causes the collector voltage of said transistor 402, and in consequence the voltage of not only the conductor layer 132 but also 135 and 138 to have I50 volts alike. As a result, the constricted plasma 18 disposed on the conductor 131 shifts to the nearest conductor 132. Said shift of the constricted plasma 18 is supposed to arise from the breakdown of an electron sheath formed near the conductor 132 or decreased impedance in its neighborhood due to the arrival of electrons. There will now be further detailed the aforementioned shift of the constricted plasma 18 by reference to FIG. 16. The wave form 401A denotes an input to the base of the transistor 401, the wave forms 402A, 403A and 404A respectively indicate an input to the base of the

transistors

402, 403 and 404 and the wave forms 421A to 424A respectively represent those of volts output signals appearing at the terminals 421 to 424. When the first pulse of the signal 401A is supplied to the transistor 401, it is cut off to cause the first pulse of the signal 421A to be presented at the terminal 421 and in consequence the constricted plasma 18 to be generated on the conductor layer 131. Next when the first pulse of the signal 402A is impressed on the transistor 402, then the first pulse of the signal 422A appears at the terminal 422, causing the constricted plasma 18 to shift to the adjacent conductor layer 132. In the similar manner, the constricted plasma 18 is progressively carried to the conductor layer 134. When, under such condition, the transistor 402 is supplied with the second pulse of the signal 402A, there appears again a pulse of 150 volts at the terminal 422. At this time, however, the constricted plasma 18 is brought to the conductor layer 135 which is disposed nearest to the conductor layer 134 and already supplied with voltage. In the same way, the constricted plasma 18 is forwarded to the conductor layers 136, 137 in turn, that is, to the right side of FIG. 15. Upon arrival at the last conductor layer, the constricted plasma 18 is reset at the initial conductor layer 131 by the second pulse of the signal 401A.

FIG. 17 illustrates still another scanning system according to the present invention for a one-dimensional display. The emitters of the transistors 401 to 404 are jointly connected to the negative terminal of a 40 volt power source 46, the positive terminal of which is grounded. The collectors of said transistors 401 to 404 are grounded through a common resistor 43, and also to the output terminals 421 to 424 of the scanning circuit of FIG. 17. Unless supplied with negative input, the transistors 401 to 404 all remain conducted. When, under such condition, the transistor 401 is supplied with the first pulse of the first signal 401A, it is turned off to cause the voltage at the terminal 421 to rise and in consequence the constricted plasma 18 to be generated on the conductor layer 131. When, under such condition, the transistor 402 is impressed with the first pulse of the signal 402A, then the constricted plasma 18 shifts in the same way as described above.

FIGS. 18 to 20 collectively present still another scanning system according to the present invention for a one-dimensional display. In this case there are used three transistors 401 to 403 as shown in FIG. 18. Scanning signals appear at three output terminals 421 to 423, output from which is further supplied to the conductor layers 131, 132 in the manner indicated in FIG. 19. The constricted plasma 18 formed on the conductor layer 131 shifts to the conductor layer 132 in the same way as in the preceding cases. At the time of FIG. 20, the conductor layers 131 and 132 have negative 40 volts with respect to the cathode 7, causing the constricted plasma 18 to be carried to the conductor layer 133.

In the similar manner, the constricted plasma passes through the holes 12 of the plasma constricting member 11 to carry out one-dimensional scanning.

FIGS. 21 to 25 show a scanning system according to the present invention for a two-dimensional display. FIG. 21 indicates a plasma constricting member 11 for a two-dimensional display. Said member 11 consists of many lateral rows of

conductor layers

1311, 1312 used in a one-dimensional display and many longitudinal columns of conductor layers 13 collectively pres enting a matrix pattern. The conductor layers 1311, 1321, 1331, 1341 13n1 constituting a longitudinal column on the extreme left side of said matrix are impressed with reset signals V to V,, shown in FIG. 22. The remaining conductor layers forming a series of Iongitudinal columns as 1312, 1322, 1332 1313, 1323, 1333 1314, 1324, 1334 are respectively connected together. Each column of conductor layers is connected to a fourth column, that is, with intervening two columns left out. Every three consecutive columns of conductor layers except for the first column consisting of the conductor layers 1311, 1321, 1331, 1341 are supplied in turn with scanning signals 11,, H and H, respectively shown in FIG. 22.

There will now be described by reference to FIG. 22 the system of FIG. 21 for scanning the plasma constricting member 11. When a reset signal V is supplied to the conductor layer 1311, there is formed a constricted plasma at a point corresponding to said conductor layer 1311. Upon successive impression of the first pulse of the scanning signals H H and H, on the conductor layers 1312, 1313 and 1314, the constricted plasma 18 is shifted to said conductors in turn. Simi larly upon successive impression of the second pulse of the scanning signals 11,, H and H, on the conductor layers 1315, 1316 and 1317, the constricted plasma 18 is carried to said conductor layers in turn. The same applies with the third and following pulses of the scanning signals 11,, H and 11,, though the associated conductor layers are changed. When, under such condition, there is impressed, for example, the reset signal V on the conductor layer 1321, the constricted plasma shifts thereto. Similarly, the succeeding

conductor layers

1322, 1323 are scanned in turn for a twodimensional display.

FIG. 23 is a modification of the plasma constricting member 11 capable of giving forth a discharge light at the same number of places as, but with a smaller number of scanning signals than, in the case of FIG. 21. The plasma constricting member of FIG. 23 has essentially the same arrangement as that of FIG. 21, and also permits the use of the same reset and scanning signals as shown in FIG. 22. But the plasma constricting member of FIG. 23 differs from the preceding types in that excluding the topmost conductor layer 131 1 of the longitudinal column of conductor layers on the extreme left side of the matrix, the remainder 1321 to 13111 of said column consists of such number of conductor layers as is divisible into three equal groups and every three corresponding conductor layers of these groups are connected together and supplied with reset signals V to V respectively at the same time.

According to the above-mentioned scanning system, where the constricted plasma 10 is made to move to the conductor layer 1321 from, for example, the conductor layer 131n, the reset signal V is supplied to the conductor layers [13 (I(+1)1] and [13(2I()1] as well as to the conductor 1321. In this case, however, the constricted plasma 13 unfailingly shifts to the nearest conductor layer 1321 as apparent from the previous description. Accordingly, the scanning system of FIG. 23 permits the number of reset signals to be reduced to one aliquot part of that required in FIG. 21.

FIGS. 24 and 25 illustrate circuit arrangements to carry out the scanning system of FIG. 21. Referring to FIG. 24, there is connected a discharge power source of 200 volts between the anode 51 and cathode 52 of a discharge tube 50, with said cathode 52 grounded. The conductor layers 13 included in the plasma constricting member 11 disposed in the discharge tube 50 are grounded through the corresponding high resistors R, having as high a resistance as several hundred kiloohms. The conductor layers 13 are so connected as to cause the scanning signals I-I to II, to be supplied thereto from the collectors of transistors 55 connected to a scanning power source 54 of to I50 volts only when said transistors 55 are cut off. On the other hand, the reset signals V 1 to V, are supplied to the conductor layers 13 from the collectors of transistors 56 connected to said scanning power source 54 only when said transistors 56 are cut off.

In the circuit of FIG. 24, the potential of both positive and negative poles of the power source 54 is made to float above that of the cathode 52 by the resistor R In FIG. 25, the positive side of a power source 57 of, for example, 40 volts is grounded and the negative side thereof is connected to the emitters of the

transistors

55 and 56, the collectors of which are grounded through the corresponding high resistors R,,. According to the scanning system of FIG. 25, the conductor layer associated with a discharge is supplied with 40 negative volts by selectively conducting the

transistor

55 or 56 to cause the constricted plasma to shift elsewhere.

In all the foregoing embodiments, the cathode of the discharge tube consists of a hot type. As shown in FIG. 26, however, even a cold cathode 60 of course permits the present invention to be practised in the same manner. The other parts and function of FIG. 26 are the same as those of the embodiments including a hot cathode and description thereof is omitted. While, in this case, a display by plasma illumination can be observed from the front panel 2 by preparing the anode 4 from transparent conductor layer, it is also permissible to cause said display to be observed from the side of the cold cathode 60 by forming it of a transparent conductor layer.

What we claim is:

l. A gas discharge display apparatus comprising:

a transparent envelope containing a gaseous atmosphere suitable for providing a constricted glow discharge;

a common cathode electrode provided on one inner surface of said envelope;

a transparent common anode electrode provided on another inner surface of said envelope; and

a plasma constricting member disposed between said common cathode and anode electrodes, said plasma constricting member having a plurality of plasma constricting holes therein and a plurality of plasma constricting hole electrodes provided on the inner surface of said holes, respectively, said plasma constricting hole electrodes being isolated from each other and the diameter of said plasma constricting holes being smaller than that of a plasma space created in front of said common cathode electrode, at least selected ones of said plasma constricting hole electrodes being applied with a changeover pulse voltage in turn at a preset interval to provide an information display using a discharge light produced from a constricted plasma formed in said plasma constricting holes.

2. A display apparatus according to claim 1 wherein the plasma constricting member is so constructed that a maximum difference Ar between the diameter of plasma space near the cathode and that of the plasma constricting hole and the mean free path A2 of electrons near said hole have a relationship of Ar/).e l.

3. A display apparatus according to claim 1 wherein the plasma constricting member has plasma constricting holes for a one-dimensional display arranged at a substantially equal interval.

4. A display apparatus according to claim 1 wherein the plasma constricting member has plasma constricting holes arranged in a matrix form for a twodimensional display.

5. A displaying apparatus according to claim 1 wherein said gaseous atmosphere consists essentially of at least one of helium, neon, argon, nitrogen, hydrogen and mercury introduced at a pressure of several mm Hg.

6. A display apparatus according to claim I wherein there is additionally provided scanning means for selectively supplying the plasma constricting hole electrodes with scanning voltage.

7. A display apparatus according to claim 6 wherein the scanning means selectively impresses the constricting hole electrodes with scanning voltage substantially equal to the anode voltage.

8. A display apparatus according to claim 6 wherein the scanning means selectively supplies the constricting hole electrodes with scanning voltage lower than the voltage of the cathode.

9. A display apparatus according to claim 6 wherein the scanning means impresses any two adjacent ones of the constricting hole electrodes with different potentials.

10. A display apparatus according to claim 9 wherein the constricting hole electrodes are formed in plasma constricting holes arranged in a matrix form for a twodimensional display.

11. A display apparatus according to claim 4 wherein there are provided means for supplying reset signals for longitudinal scanning to mutually connected plasma constricting hole electrodes in turn which constitute the first longitudinal column of the matrix, and means for supplying scanning signals to the mutually connected plasma constricting hole electrodes of every two consecutive columns with intervening two columns omitted, said scanning signals being varied for every three groups, each comprising said two consecutive columns.

12. A display apparatus according to claim 11 wherein, excluding the topmost constricting hole electrodes of the first column of the matrix, the remaining constricting hole electrodes have such a number divisible into a plurality of equal groups and there is additionally provided means for connecting together those constricting hole electrodes of said groups which are disposed in the corresponding position.

13. A gas discharge display apparatus comprising:

a common cathode electrode provided on one inner surface of said envelope; and

a plasma constricting member disposed at a position opposite to said common cathode, said plasma constricting member having a plurality of plasma constriting holes therein and a plurality of anode electrodes provided at one end of said holes furthest from said common cathode, respectively, said anode electrodes being isolated from each other and the diameter of said plasma constricting holes being smaller than that of a plasma space created in front of said common cathode electrode, at least selected ones of said anode electrodes being applied with a changeover pulse voltage in turn at a preset interval to provide an information display using a discharge light produced from a constricted plasma formed in said plasma constricting holes.

14. A display apparatus according to claim 13 wherein the cathode is a cold type comprising a transparent conductor layer.

15. A display apparatus according to claim 13 wherein there is additionally provided scanning means for selectively impressing the anode electrodes with scanning voltage.

16. A display apparatus according to claim 13 wherein the unit anode members are coated with a fluorescent layer.

17. A display apparatus according to claim 13 wherein the plasma constricting member is so constructed that a maximum difierence Ar between the diwherein the plasma constricting member has plasma constricting holes arranged in a matrix form for a twodimensional display.

20. A display apparatus according to claim 13 wherein said gaseous atmosphere consists essentially of at least one of helium, neon, argon, nitrogen, hydrogen and mercury introduced at a pressure of several mm Hg.

t t t

Claims

1. A gas discharge display apparatus comprising: a transparent envelope containing a gaseous atmosphere suitable for providing a constricted glow discharge; a common cathode electrode provided on one inner surface of said envelope; a transparent common anode electrode provided on another inner surface of said envelope; and a plasma constricting member disposed between said common cathode and anode electrodes, said plasma constricting member having a plurality of plasma constricting holes therein and a plurality of plasma constricting hole electrodes provided on the inner surface of said holes, respectively, said plasma constricting hole electrodes being isolated from each other and the diameter of said plasma constricting holes being smaller than that of a plasma space created in front of said common cathode electrode, at least selected ones of said plasma constricting hole electrodes being applied with a changeover pulse voltage in turn at a preset interval to provide an information display using a discharge light produced from a constricted plasma formed in said plasma constricting holes.

2. A display apparatus according to claim 1 wherein the plasma constricting member is so constructed that a maximum difference Delta r between the diameter of plasma space near the cathode and that of the plasma constricting hole and the mean free path lambda e of electrons near said hole have a relationship of Delta r/ lambda e>1.

4. A display apparatus according to claim 1 wherein the plasma constricting member has plasma constricting holes arranged in a matrix form for a two-dimensional display.

6. A display apparatus according to claim 1 wherein there is additionally provided scanning means for selectively supplying the plasma constricting hole electrodes with scanning voltage.

10. A display apparatus according to claim 9 wherein the constricting hole electrodes are formed in plasma constricting holes arranged in a matrix form for a two-dimensional display.

13. A gas discharge display apparatus comprising: a transparent envelope containing a gaseous atmosphere suitable for providing a constricted glow discharge; a common cathode electrode provided on one inner surface of said envelope; and a plasma constricting member disposed at a position opposite to said common cathode, said plasma constricting member having a plurality of plasma constriting holes therein and a plurality of anode electrodes provided at one end of said holes furthest from said common cathode, respectively, said anode electrodes being isolated from each other and the diameter of said plasma constricting holes being smaller than that of a plasma space created in front of said common cathode electrode, at least selected ones of said anode electrodes being applied with a changeover pulse voltage in turn at a preset interval to provide an information display using a discharge light produced from a constricted plasma formed in said plasma constricting holes.

17. A display apparatus according to claim 13 wherein the plasma constricting member is so constructed that a maximum difference Delta r between the diameter of plasma space near the cathode and that of the plasma constricting hole and the mean free path lambda e of electrons near said hole have a relationship of Delta r/ lambda e>1.

18. A display apparatus according to claim 13 wherein the plasma constricting member has plasma constricting holes for a one-dimensional display arranged at a substantially equal interval.

19. A display apparatus according to claim 13 wherein the plasma constricting member has plasma constricting holes arranged in a matrix form for a two-dimensional display.