U.S. patent number 3,749,969 [Application Number 05/112,293] was granted by the patent office on 1973-07-31 for gas discharge display apparatus.
Invention is credited to Hiroo Hori, Shoichi Miyashiro, Kazuyuki Ogawa.
United States Patent |
3,749,969 |
Miyashiro , et al. |
July 31, 1973 |
GAS DISCHARGE DISPLAY APPARATUS
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.
Inventors: |
Miyashiro; Shoichi
(Kanagawa-ku, Yokohama-shi, JA), Ogawa; Kazuyuki
(Kanazawa-ku, Yokohama-shi, JA), Hori; Hiroo
(Kawasaki-shi, JA) |
Family
ID: |
11723090 |
Appl.
No.: |
05/112,293 |
Filed: |
February 3, 1971 |
Foreign Application Priority Data
Current U.S.
Class: |
345/62;
313/582 |
Current CPC
Class: |
H01J
17/498 (20130101); G09G 3/285 (20130101); H01J
17/494 (20130101) |
Current International
Class: |
G09G
3/29 (20060101); G09G 3/28 (20060101); H01J
17/49 (20060101); H05b 037/00 () |
Field of
Search: |
;313/201,220
;315/169R,169TV |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lake; Roy
Assistant Examiner: Dahl; Lawrence J.
Claims
What we claim is:
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.
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 two-dimensional 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 1 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 two-dimensional 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 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.
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 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.
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.
Description
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. 1 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. 1 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. 1;
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 VII--VII of FIG. 6 as viewed in the
direction of the arrows;
FIG. 8 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. 10 is a sectional view of another display tube according to
the invention;
FIG. 11 is a sectional view on line XI--XI of FIG. 10;
FIG. 12 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. 13 and 14 indicate the circuit arrangements of other scanning
devices used in the gas discharge display apparatus of the
invention;
FIG. 15 illustrates the connection between the plasma constricting
member and scanning device of FIG. 14;
FIG. 16 presents the wave form of signals showing the operation of
the scanning device of FIG. 14;
FIGS. 17 to 20 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 display;
FIGS. 24 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 one- and two-dimensional
display of information, there is first described an embodiment
associated with a one-dimensional display.
In FIGS. 1 and 2, the front panel 2 of a sealed vessel 1 is made of
a transparent material, for example, glass. The vessel 1 is first
evacuated through an evacuating port 3 by evacuating means (not
shown) to high vacuum and then filled with proper gas, for example,
helium gas of 4 mmHg. 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 11 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 B--B 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
B--B 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 B--B of the discharge tube in a plane intersecting said axis
B--B 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 .DELTA.r and the mean free path of
electrons through said points as .lambda.e, when there was
established a relationship of .DELTA.r>.lambda.e between both
factors, then there arose an intense light. In case of
.DELTA.r<.lambda.e, 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
.DELTA.r>.lambda.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.sub.1 and the
mean free path of electrons as .lambda.e.sub.1, variation in the
tube diameter may be expressed as .DELTA.r.sub.1, and in case the
gas pressure is increased to P.sub.2 and the mean free path of
electrons to .lambda.e.sub.2, then the tube diameter will only have
to be varied to .DELTA.r.sub.2. To obtain a relationship of
.DELTA.r>.lambda.e 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.sub.1, the tube diameter
will have a broad variation of .DELTA.r.sub.2 with respect to the
mean free path .lambda.e.sub.1 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 .DELTA.r>.lambda.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 J and the total current passing through the D--D
section of the tube as I. In case of S.sup. . J .gtoreq. I, there
will not appear a prominent change in the electric field in the
D--D section, through the aforesaid construction conditions may be
fully met. In constrast, where there is introduced sufficient
current to realize S.sup. . J<I, 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 D--D 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 20 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 25 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 due 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 30 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 38 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 terminal 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 15 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.sub.n 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.sub.1 and P.sub.n, 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. Similar y 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 150 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 150 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 t.sub.3 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 18 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 presenting 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.sub.1 to V.sub.n shown in FIG. 22.
The remaining conductor layers forming a series of longitudinal
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 H.sub.1, H.sub.2 and H.sub.3 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.sub.1 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.sub.1, H.sub.2 and H.sub.3 on the
conductor layers 1312, 1313 and 1314, the constricted plasma 18 is
shifted to said conductors in turn. Similarly upon successive
impression of the second pulse of the scanning signals H.sub.1,
H.sub.2 and H.sub.3 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 H.sub.1, H.sub.2 and H.sub.3, though the
associated conductor layers are changed. When, under such
condition, there is impressed, for example, the reset signal
V.sub.2 on the conductor layer 1321, the constricted plasma shifts
thereto. Similarly, the succeeding conductor layers 1322, 1323 . .
. are scanned in turn for a two-dimensional 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
1311 of the longitudinal column of conductor layers on the extreme
left side of the matrix, the remainder 1321 to 13n1 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.sub.2 to V.sub.n respectively at the same time.
According to the above-mentioned scanning system, where the
constricted plasma 18 is made to move to the conductor layer 1321
from, for example, the conductor layer 131n, the reset signal
V.sub.2 is supplied to the conductor layers ?13 (K+1)1! and
?13(2K)1! as well as to the conductor 1321. In this case, however,
the constricted plasma 18 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.sub.g having as
high a resistance as several hundred kiloohms. The conductor layers
13 are so connected as to cause the scanning signals H.sub.1 to
H.sub.3 to be supplied thereto from the collectors of transistors
55 connected to a scanning power source 54 of 100 to 150 volts only
when said transistors 55 are cut off. On the other hand, the reset
signals V.sub.1 to V.sub.n 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.sub.g. 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.sub.g. 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.
* * * * *