Flat panel display system

A flat panel display arrangement is disclosed in which a plurality of plasma sacs are simultaneously generated from cathodes in sections disposed in side-by-side relation, supporting walls being provided between adjacent sections. Row and column electrodes are provided in orthogonal relation for effecting simultaneous scanning of all sections, using a zig-zag scanning arrangement.

This invention relates to a flat panel display system and more particularly 
to a flat panel display system utilizing a plasma sac scanning and which 
produces a highly accurate raster type display with uniform luminance 
characteristics throughout while having minimum complexity and being 
readily and economically manufacturable. The display panel of the system 
may be of any desired size and its area may be many times larger than the 
area obtainable with conventional displays. The system is further 
advantageous in that it does not require highly expensive, complex and 
bulky electronic control and drive circuitry. 
BACKGROUND OF THE INVENTION 
Various flat panel displays have heretofore been proposed for producing a 
television picture or for alphanumeric and computer graphic display 
purposes. The systems as proposed would have manifest advantages with 
respect to the size of the image which might be displayed, when compared 
with conventional television picture tubes in which any increase in 
picture area greater than an area having about a 25 inch diagonal 
measurement results in an inordinate increase in bulk and weight. However, 
the arrangements as heretofore proposed have either been inoperable or 
have been so impractical or expensive that they have not been used 
successfully other than for experimental purposes and in special 
applications. 
In certain of the prior art systems, individual cells or units are provided 
for producing each image spot, each cell or unit being operable 
independently of the other, with a matrix of row and column conductors 
being driven electrically to effect sequential operation of the cells in a 
predetermined raster pattern. Such arrangements have been very expensive 
to construct and have required circuitry which is complex and expensive. 
With regard to particular prior art disclosures, the Watanabe U.S. Pat. No. 
3,622,829 proposed a flat panel display arrangement using a gas plasma as 
a cathode with electrons being extracted from the plasma by a 
positive-potential mesh to be directed toward a control-grid array. The 
grid as disclosed is in the form of a set of holes in a substrate with 
electrodes in parallel strips along one surface of the substrate and with 
a second set of parallel strips along the other surface of the substrate, 
in orthogonal relation to the first set. By applying positive potentials 
to any selected pair of the two sets of electrodes, the electrons are 
extracted from the plasma and accelerated to strike a phosphor and produce 
a luminescent spot. 
The Watanabe arrangement would have the potential advantage of increased 
efficiency and brightness, as compared to systems using other types of 
cathodes, but there would be practical difficulties in attempting to use 
the system, especially in a large size display. One problem which is not 
mentioned or recognized in the Watanabe patent is the problem of support 
of the front and rear walls of the panel, when the panel is of large size. 
Since the absolute pressure within the device must be quite low, the 
atmospheric pressure applied to the front and rear walls can produce 
extremely large forces when the device is of a large size. For example, in 
a panel which is 30 inches square, the total forces applied to the front 
and rear walls may be well over 10,000 pounds and such walls would have to 
be quite thick and heavy. 
Another problem with the Watanabe type of design is with respect to the 
electrical circuitry required to drive all of the electrodes of both sets. 
Certain problems with the Watanabe type of design may be overcome in 
devices using plasma sac scanning. The production of a plasma sac is 
described in a journal article entitled "A Picture-Display Panel Using a 
Constricted Glow Discharge", by H. Hori et al, IEEE transactions on 
Electron Devices, Vol. ED-21, No. 6, June 1974. As described, a plasma sac 
is caused to be produced on the cathode side of an apertured insulator and 
by controlling the potential applied to electrodes, the plasma sac may be 
caused to move from one aperture to another. 
The Miyashiro et al. U.S. Pat. No. 3,749,969 also discloses a plasma sac 
and discloses a two-dimensional scanning arrangement for effecting 
movement of the plasma sac in a flat panel type of display. To scan a row, 
a sac is initiated at the start of the row and is caused to move 
progressively from cell to cell by changes in the potential on a control 
electrode associated with each of the cells. Such an arrangement has the 
potential of reducing the complexity, size and cost of the circuitry 
required to effect a scanning operation. However, the aforementioned 
problems with respect to the permissible size of the displays are not 
recognized and dealt with. 
In my U.S. Pat. No. 4,130,777 I disclose a scanning means and method for a 
plasma-sac-type gas-discharge image display panel in which a plurality of 
electron-beam-generating plasma sacs are simultaneously formed from a 
gas-discharge plasma or plasmas and in which scanning means are provided 
for activating in sequence and group-by-group consecutive groups of plasma 
sacs in a row until an entire row is scanned. 
The scanning means and method as disclosed in my aforesaid patent are 
highly advantageous. However, certain problems with respect to 
constructing a large size image display panel were not recognized. In 
particular, my patent discloses the use of a plurality of elongated hollow 
cathodes on side-by-side relation with there being a limited number of row 
electrodes associated with each hollow cathode. The front wall of the 
panel is disclosed as being supported from the forward edges of supporting 
walls which extend between the electrodes of the hollow cathodes to 
separate one hollow cathode from the cathodes adjacent thereto, the 
electrode structure and associated insulators being interposed between 
such forward edges and the front wall. 
With such supporting walls, it would be possible to support the front and 
rear walls of a panel having a very large size since the spacing distance 
between one supporting wall to another may be quite small and a large 
number of supporting walls can be provided extending throughout the entire 
area of the panel. Thus, the arrangement would not only provide adequate 
support for the front and rear walls, but would permit such walls to be 
relatively thin and light in weight. 
A problem with such a construction, not recognized in my patent and not 
recognizable from consideration of the prior art, is with regard to 
effecting scanning of the rows which are adjacent the supporting walls. It 
is found that blank spaces are produced in the image for the reason that 
scanning of rows near such supporting walls is unreliable. After 
investigation of the problem, it was found that the walls apparently 
produce a non-uniform field distribution such that in many cases, the 
plasma sac has a tendency to either move away from the wall or to become 
extinguished when scanning potentials are applied to the column electrodes 
designed to produce scanning movement parallel to the wall. It was found 
that in some cases, the plasma sac improperly moved along a row spaced a 
distance from the wall rather than a row adjacent thereto. 
SUMMARY OF THE INVENTION 
This invention was evolved with the general object of overcoming 
disadvantages of prior art arrangements and of providing a flat panel 
display which can be of any desired size and which will produce uniform 
luminescense characteristics throughout the entire area of display. 
Another object of the invention is to provide a flat panel display 
arrangement which is readily and economically manufacturable even when of 
quite large size. 
A further object of the invention is to provide a flat panel display 
arrangement which produces a very bright image while being highly 
efficient and reliable. 
An important aspect of the invention is in the recognition of the 
aforementioned problem with the construction of my U.S. Pat. No. 4,130,177 
and in the discovery that a plasma sac may be reliably moved in a path 
adjacent a support wall by control of the field distribution adjacent such 
a path. 
As a result of my discovery and in accordance with this invention, a flat 
panel display is provided which preferably includes means for developing a 
plasma sac movable in a certain pattern to produce a visible scanning spot 
behind a front wall of the device. The front wall is supported from the 
front edges of side walls and from the front edges of a plurality of 
intermediate supporting walls spaced in parallel relation the side walls. 
To effect the scanning movement of the spot, electrode means are provided 
including electrodes which extend in parallel relation to each other and 
in transverse relation to the intermediate supporting walls. In addition, 
the electrode means include portions adjacent the edges of the supporting 
walls, in parallel relation to such walls and in transverse relation to 
the other electrodes. A suitable potential may be applied to the 
additional electrode in a manner such that scanning movement of the spot 
may be effected from one position to another along the front edge of the 
supporting wall. 
With this comparatively simple arrangement, it is possible to have display 
points which are uniformly distributed throughout the entire viewing area 
of the panel and to produce luminence characteristics which are 
substantially uniform at all such display points, including points which 
are adjacent the front edges of supporting walls, as well as points which 
are spaced a substantial distance therefrom. 
The construction of the display arrangement of the invention may be similar 
to that of my aforesaid U.S. Pat. No. 4,130,777, differing therefrom in 
that it includes row and column electrodes in orthogonal relation and also 
with respect to the manner of application of control signals to allow 
scanning movement along the front edge of a supporting wall. 
One embodiment of the invention also differs from that of my patent with 
respect to the orientation of supporting walls. In the construction of my 
patent, the plasma sac in scanning a row which corresponds to the scanning 
of one line of an image is caused to move in a direction parallel to 
supporting walls, there being a plurality of rows corresponding to each 
hollow cathode between supporting walls. In one embodiment in accordance 
with the invention, however, the direction of scanning of rows is 
transverse to supporting walls, rather than parallel to such walls as in 
the construction of my patent. With this arrangement, the hollow cathodes 
provided between supporting walls are thus in a vertical column direction 
rather than in a horizontal row direction. 
Another important feature of the invention relates to a multiple sac 
arrangement for simultaneous scanning of display points in a plurality of 
sections. The display is divided into a plurality of sections in adjacent 
relation and hollow cathodes associated with such sections are operable to 
simultaneously produce a plurality of plasma sacs with one plasma sac 
being produced in each section. All of such plasma sacs are movable 
simultaneously to effect simultaneous scanning of the display points of 
all sections. 
An important advantage of this arrangement is that the velocity of movement 
of the plasma sacs required in any given application can be greatly 
reduced with respect to the velocity of movement required in prior 
one-point-at-a-time scanning arrangements in which the scanning of a row 
is effected at the line scan rate. For television and similar 
applications, the arrangement may require a storage of a video signal in a 
manner such as to permit the simultaneous scanning movement a plurality of 
sacs. However, the required signal storage capabilities of the system are 
not difficult to provide. In particular, by combining this multiple sac 
simultaneous scan feature with the vertical orientation of the cathodes, 
all sacs are in one row and only one scan line of an input video signal 
need be stored at any one time. 
Another important feature of the arrangement relates to a combination of 
one or more of the aforementioned features with a zig-zag scanning 
arrangement in which each sac is moved along each row from one column to 
another within its section until reaching the column at one end of the 
row, the sac being then moved along that column to the adjacent end of the 
next adjacent row and thence in an opposite direction from one column to 
another along the adjacent row. With this arrangement, the sac may be 
produced at one end of the section and may scan all display points within 
the section, no reinstitution of the sac being required. 
The sac may be initiated at one end of a section at the field or frame rate 
of a video signal and, in accordance with a specific feature of the 
invention, the sac may be developed at a central point of a section, at a 
point spaced from the supporting walls which define the section. 
Additional features of the invention relate to configurations of electrodes 
and other elements of the panel and to the manner of assembly thereof to 
obtain improved performance and reliability while allowing construction of 
the panel at low cost. 
Further features relate to the combination of the panel with electrical 
circuitry operative to obtain and utilize the advantages of the 
capabilities of scanning adjacent a supporting wall and the advantages of 
the multiplesac simultaneous scan feature. The electrical circuitry of the 
illustrated embodiment is such as to permit reproduction of pictures from 
standard signals of the type produced in conventional television systems 
and its includes features which may be used in other types of displays. 
This invention contemplates other objects, features and advantages which 
will become more fully apparent from the following detailed description 
taken in conjunction with the accompanying drawings.

DESCRIPTION OF A PREFERRED EMBODIMENT 
Reference numeral 10 generally designates a flat panel display system 
constructed in accordance with the principles of this invention. The 
illustrated system 10 comprises a display panel unit 11 connected to a 
control unit 12 through suitable cables 13, 14 and 15. The display panel 
unit 11 as illustrated and specifically described herein is a 
comparatively small unit having display points arranged in 88 rows and 112 
columns and having limited applications. It has been used for testing and 
demonstration purposes in reproducing a small portion of a picture 
reproduced from broadcast television signals by a conventional television 
receiver and it will be understood that by increasing the size of the unit 
to provide more rows and columns, the unit might be used for reproducing a 
complete picture such as produced by a conventional television receiver. 
The horizontal and vertical dimensions of the structure as well as the 
dimensions of component elements may be increased or decreased as desired 
to produce a picture of any desired size. It is also noted that the system 
as illustrated and described is designed for black and white reproduction 
but the principles of the invention are applicable as well to systems 
designed for color reproduction. 
Referring to FIG. 2, the panel unit 11 includes a transparent glass front 
wall 16, an electrode assembly 17 immediately behind the front wall 16 and 
a rear wall 18 which may be of any desired material. The unit 11 further 
includes top and bottom wall 19 and 20, a pair of side walls 21 and 22 and 
seven intermediate supporting walls 23, 24, 25, 26, 27, 28, 29 and 30 
between the side walls 21 and 22, positioned in spaced vertical planes in 
parallel relationship to the side walls 21 and 22. The forward end 
portions of the supporting walls 23-30 are tapered to provide very narrow 
forward faces which are in supporting engagement with rearward surface 
portions of the electrode assembly, the front wall 16 being supported from 
the supporting walls 23-30 through the electrode assembly 17. With this 
arrangement, the front wall 16 can be relatively thin and can have a large 
area while being adequately supported, it being noted that the pressure 
within the panel is very low as compared to atmospheric pressure. 
By way of example, the spacing of the center planes of the intermediate 
supporting walls 23-30 may be 1.12 inches and between each adjacent pair 
of supporting walls there may be sixteen columns of display points with 
0.07 inch spacings between the center lines of the columns. With 88 rows 
of display elements, also having a 0.07 inch spacing, a display area of 
6.16 by 7.84 inches is provided. The dimension of the supporting walls 
23-30 as well as the top, bottom and side walls 19-22, between the 
rearward face of the electrode assembly 17 and the forward face of the 
rear wall 18, may be 2.2 inches and the overall depth of the panel may be 
approximately 2.7 inches. 
It should be noted that the foregoing dimensions as well as those set forth 
hereinafter are provided for the purpose of illustrative example and are 
not to be construed as limitations. 
In general, the unit 11 is designed to reproduce a picture by producing 
light of variable intensity at the display points which are arranged in 
rows and columns. The light at each display point is produced by 
accelerating electrons to a high velocity and impinging them on a 
cathodoluminescent picture element on the rear surface of the front wall 
16, the brightness being controlled by the magnitude of a video signal 
applied to a control electrode. 
The source of the electrons is a plasma sac which is produced in the 
rearward portion of the electrode assembly. In the illustrated embodiment, 
it is produced from ionized gas within a hollow cathode of generally 
U-shaped cross-sectional configuration. To scan the display points, 
signals are applied to row and column electrodes in a manner such that a 
plasma sac is moved from one display point to another in a certain 
pattern. 
Important features of the invention relate to the simultaneous production 
of a plurality of plasma sacs from hollow cathodes which are located 
between adjacent ones of the supporting walls 23-30, seven hollow cathodes 
31-37 being provided, and to the use of a zig-zag scanning arrangement 
with signals being applied to scanning electrodes in a manner such that 
the plasma sacs may be moved into close proximity to a supporting wall. 
With these features, display points are uniformly distributed throughout 
the entire viewing area of a panel and the luminence characteristics at 
all display points are substantially uniform. At the same time, the 
arrangement allows use of supporting walls spaced short distances apart to 
provide the advantageous support of the front and rear walls of the unit. 
The hollow cathode 31 is formed by a member of sheet metal having a 
generally U-shaped cross-sectional configuration and including a portion 
31a disposed against the forward surface of the rear wall 18 and portions 
31b and 31c which extend forwardly along the surfaces of the supporting 
walls 23 and 24 to forward edges which are spaced rearwardly a substantial 
distance from the electrode assembly 17. The construction of the other 
hollow cathodes 32-37 is the same as that of the hollow cathode 31. 
The construction of the electrode assembly is illustrated in FIG. 3 which 
is an exploded isometric view illustrating portions of electrodes, spacers 
and other elements. The assembly 17 includes two electrodes 39 and 40 in a 
common plane, such electrodes being formed of very thin conductive metal 
which may, for example, be 0.003 inches in thickness. The electrode 39 has 
openings therethrough in rows and columns corresponding to display points 
of the picture to be produced, there being sixteen columns between each 
adjacent pair of the supporting walls and there being 88 rows in the 
disclosed embodiment. Electrode 39 is operated at a potential such as to 
develop a biasing field which prevents unwanted electrons from entering 
the assembly 17 and thereby cuts down unwanted background light. 
The electrode 40 extends along the upper edge of the electrode 39 and 
includes a series of openings, one for each cathode, located at 
intermediate positions with respect to the supporting walls. Thus, as 
illustrated in FIG. 3, there is one opening 41 in the electrode 40 located 
about mid-way between the walls 23 and 24. In the illustrated arrangement, 
opening 41 is in the ninth column and there are corresponding openings for 
each of the other hollow cathodes in the ninth column thereof. The 
electrode 40 is used for the purpose of initiating development of a plasma 
sac at the openings therein. 
A plurality of row electrodes 42, are provided in a common plane in 
forwardly spaced relation to the electrode 39, the row electrodes 42 
having openings aligned with the openings in the electrode 39. Another 
electrode 43 is provided in co-planar relation to the row electrodes 42 
and is positioned above the uppermost row electrode in alignment with the 
electrode 40. An insulating spacer 44 is provided between the plane of the 
electrodes 39 and 40 and the plane of the electrodes 42 and 43. The spacer 
44 has openings aligned with the openings in the electrodes 39 and 40 and 
has an opening 45 aligned with opening 41 of electrode 40. A plasma sac is 
initially developed in opening 45 at the start of a frame. 
A plurality of column electrodes 47 are positioned in a common plane spaced 
forwardly from the plane of the row electrodes 42 and the control 
electrode 43, there being one column electrode 47 for each column of the 
display. An insulating spacer 48 is provided between the column electrodes 
47 and the electrodes 42 and 43, the spacer 48 having openings aligned 
with the openings in the electrodes and spacer positioned rearwardly 
therefrom. 
The construction of one of the column electrodes 47 is shown in FIG. 4 and, 
as shown, it has a multiplicity of openings therethrough, the purpose 
being to control positioning of a plasma sac which is disposed rearwardly 
with respect thereto while allowing passage of electrons therethrough in a 
manner as hereinafter described. By way of example, the column electrodes 
47 may be in the form of thin ribbons of metal having a thickness of 0.003 
inches, and having a width of 0.06 inches with holes being provided in six 
columns, the diameter of each hole being 0.0075 inches. 
A plurality of intensity control electrodes 50 are provided in a plane 
spaced forwardly from the column electrodes 47. A spacer 51 is provided 
between the intensity control electrodes 50 and the column electrodes 47. 
Holes are provided in the spacer 51 in line with the openings in the 
spacers which are positioned rearwardly with respect thereto. The 
intensity control electrodes 50 may be in the form of etched sheets of 
metal having a thickness of 0.003 inches and having holes therethrough, 
the diameter of each hole being 0.0075 inches and the spacing between 
holes being like that of the holes in the column electrodes 47 as 
illustrated in FIG. 4. Video signals are applied to the electrodes 50 to 
control the brightness at the display point aligned with a plasma sac of 
each section. 
A screen electrode 52 is positioned in a plane spaced forwardly from the 
plane of the intensity control electrodes 50, an insulating spacer 53 
being provided between the screen electrode 52 and the intensity control 
electrodes 50. The screen electrode may be formed of a wire screen with a 
mesh size of 325 lines per inch and a wire diameter of 0.0011 inches. 
A pair of spacers 55 and 56 are positioned between the screen electrode 52 
and the rearward face of the forward wall 16, the spacers 55 and 56 having 
openings which register with the openings in the elements spaced 
rearwardly therefrom. The spacers 55 and 56 are for the purpose of 
providing a distance of substantial length for acceleration of electrons 
to a high velocity under the influence of a relatively high voltage. Two 
of such spacers 55 and 56 are provided in order to obtain adequate 
thickness without having a thickness to opening size ratio which would 
present difficulties in fabrication. An accelerating voltage which may be 
on the order of 4,000 volts is applied between the electrodes to the rear 
of the spacer 55 and an electrode 57 on the rear face of the front wall 
16, the electrode 57 being in the form of a thin and substantially 
transparent tin oxide. A suitable cathodoluminiscent material is 
associated with the electrode 57 for producing light in response to 
bombardment by high velocity electrons. 
In the construction of the panel unit 11, a tin oxide or the equivalent is 
deposited on the rear face of the glass front wall 16 along with a 
suitable phosphor. Then the high voltage spacers 55 and 56 are placed 
together and against the rear face of the front wall 16, followed by the 
other cathodes and spacers in the order as shown, the electrodes 39 and 40 
being installed last to form the electrode assembly. The rear wall 18, top 
and bottom walls 19 and 20, side walls 21 and 22 and intermediate 
supporting walls 23-30 are also assembled with the hollow cathodes 31-37 
positioned and secured between supporting walls in the manner as shown. 
Then the front wall 16 and the electrode assembly 17 positioned thereon 
are secured against the forward surfaces of the top, bottom, side and 
intermediate supporting walls, a frit seal being provided in a manner as 
known in the art. The space within the panel unit may then be evacuated 
and filled with a suitable gas, reference being made to my U.S. Pat. No. 
4,130,777 for a description of gases suitable for the purpose. The 
pressure within the panel is then very low in relation to atmospheric 
pressure which is applied against the front and rear walls 16 and 18 as 
well as against the top, bottom and side walls 19-22. The intermediate 
supporting walls 23-30 provide support such that the front and rear walls 
can be relatively thin as compared to the thickness which would be 
required if they were supported only by the side and top and bottom walls. 
In the operation of the panel, the hollow cathodes 31-37 are placed at a 
negative potential of on the order of 400 volts relative to the electrodes 
of the assembly 17 which are at potentials relatively close to reference 
ground potential, while a high voltage is applied to the electrode 57 
relative to of on the order of 4,000 volts relative to ground potential. 
The hollow cathodes provide efficient sources of copious electrons from 
which a plasma sac may be formed in each section of the panel behind the 
row and column electrodes thereof, the plasma sac being movable from one 
position to another through application of voltage pulses to the row and 
column electrodes. 
At the start of each frame of a scanning operation, a positive voltage 
pulse is applied to the electrode 40 and at the same time a positive 
voltage pulse is applied to the electrode 43 to cause development of 
plasma sacs in register with the openings 41 and 45 and additional plasma 
sacs in register with the corresponding openings of the other sections. 
Then, while a positive pulse is applied to the uppermost one of the row 
electrodes 42, pulses are applied sequentially to the column electrodes 47 
within all sections and the sacs are moved down into the uppermost row and 
are then moved along the uppermost row to one end thereof. Thereafter, 
they are moved down into the second row and are moved to the opposite end 
thereof, a zig-zag scan operation being obtained. 
The operation may be clarified after consideration of the circuit diagram 
of FIG. 5 and the waveform diagram of FIG. 6. The circuitry includes a 
power supply terminal 60 which is connected to the biasing electrode 39 
and which may supply a voltage of on the order of plus 30 volts. The 
circuitry also includes a power supply terminal 61 which may supply a 
voltage of on the order of -400 volts and which is connected through 
current-limiting resistors 62 and 63 to the cathodes 31 and 32, as 
diagrammatically illustrated, and through similar current-limiting 
resistors to the cathodes of the other sections. 
The circuitry further includes a row driver 68 which has ten outputs 
connected to buses which are connected to the row electrodes 42 in groups 
of ten, the outputs being respectively connected to the No.'s 1-10 
electrodes, the No.'s 11-20 electrodes, etc., numbering the row electrodes 
42 from top to bottom. 
A column driver circuit 70 is provided having sixteen outputs which are 
connected to buses, the buses being connected to the sixteen column 
electrodes of each section. 
The row and column driver circuits 68 and 70 are controllable from logic 
control circuits 72, which have the outputs connected through line 73 to 
the row driver circuits 68 and sixteen outputs connected through line 74 
to inputs of the column driver circuit 70. The logic control circuits, 
when operating in a zig mode, apply signals to the column driver circuit 
70 to apply pulses to the column electrodes of all sections in a sequence 
such as to move a scanning sac from left to right from the left side of 
each section to the right side thereof. In a zag mode, signals are applied 
to the column driver circuit 70 in a manner such as to cause movement of a 
scanning sac in the opposite direction, from right to left. 
The logic control circuits 72 also apply control signals through a line 75, 
seven video driver and sample and hold circuits 76 which have seven 
outputs connected to the seven intensity control electrodes 50 for the 
seven sections of the illustrated panel. Circuits 76 have an input 
connected through line 77 to the video output of a T.V. receiver 78 which 
provides a source of input signals in the illustrated arrangement and 
which applies sync signals to logic control circuits 72 through a line 79. 
It will be understood that other sources of signals may be used. 
When operating in the zig mode, video signals stored in a previous 
horizontal line time interval are applied from the circuits 76 to the 
intensity control electrodes 50 in the same order as received, the 
scanning movements of the sacs being from left to right. When operating in 
the zag mode, the signals stored in the previous horizontal line time 
interval are applied to the intensity control electrode in an order 
opposite that in which they were received, the scanning movements of the 
sacs being from right to left. 
The logic control circuits 72 also apply control signals through line 81 to 
vertical reset and primer drivers 82 which have outputs connected through 
lines 83 and 84 to the primary electrode 40 and the reset electrode 43. 
As shown in FIG. 6, the waveform of the signal applied to the electrode 40 
is as indicated by reference numeral 88 and a signal is applied to the 
electrode 43 having a similar waveform 89 but having a different level. 
Then, a drive signal is applied to the uppermost one of the row electrodes 
42, i.e., the row No. 1 electrode, having a waveform as indicated by 
reference numeral 90. At the same time, scan pulses are sequentially 
applied to the column electrodes of the first section and to the column 
electrodes of the other sections, having a form as depicted by waveforms 
91-106 in FIG. 6. After termination of the reset pulse 89, the plasma sacs 
are moved down into the uppermost row and are thereafter moved to the 
right, being positioned at the right-hand ends of the other sections 
through application of the pulse 106. 
At this time, a drive pulse is applied to the No. 2 row electrode, having a 
waveform as indicated by reference numeral 108 and a sequence of scan 
pulses are then applied to the column electrodes as indicated by reference 
numerals 109-124. It is noted that the drive pulses 109-124 are applied in 
a reverse order, as compared to the drive pulses 91-106, and the sac is 
caused to move in the reverse direction, from right to left. 
It is also noted that the zig and zag row pulses 90 and 108 may preferably 
overlap and may have leading edges which are in leading relation to the 
initial corresponding scan pulses, thus, for example, the leading edge of 
the pulse 108 may be in leading relation to the pulse 109, as shown in 
FIG. 6. The purpose of this feature is to insure movement of the sac from 
one row to another when it is at an end position, adjacent a supporting 
wall. It is found to be important that the field conditions be carefully 
controlled in order to insure movement of the sac from one point to 
another and that care should be exercised in the application of signals 
with the proper timing as well as the proper amplitudes. 
It is noted that with the panel of the invention, a plurality of sacs are 
simultaneously generated during scanning of display points in one row and, 
as a result, the required velocity of movement of each sac is greatly 
reduced as compared to the velocity which would be required with a single 
sac operative to scan a row in one line interval. This feature is 
advantageous in obtaining a reliable scanning operation and is especially 
advantageous in a construction as illustrated in which the supporting 
walls extend vertically, allowing additional time for effecting movement 
of a scanning sac from one row to another at positions adjacent the 
supporting walls. 
It is noted that although the operation of the panel has been described 
with reference to directions and velocities of movement of the plasma 
sacs, the sacs actually do not move and the operation is such that a sac 
is formed at one position and while it is extinguished, another sac is 
formed at an adjacent position. The development of each sac establishes 
conditions for priming of another sac adjacent thereto and with the 
disclosed arrangement, a sac can be established at or "moved to" a 
position adjacent a supporting wall. However, it is difficult to reliably 
form an initial sac at a position close to a supporting wall and for this 
reason, an arrangement such as illustrated is highly advantageous, the 
initial development of the sac in each section being at a position 
intermediate the supporting walls and spaced a substantial distance 
therefrom. 
In the panel 11 as described and illustrated, the row electrodes 42 are 
behind the column electrode 47. It is also possible to dispose row 
electrodes in front of column electrodes as depicted in FIG. 7 which is an 
enlarged rear elevational view showing positions of modified row 
electrodes designated by reference numeral' 42' and portions of modified 
column electrodes designated by reference numeral 47'. 
In this arrangement, the row electrodes 42' may have a form like that of 
the column electrodes 47 of the panel 11, being formed with small holes 
therethrough, and the column electrodes 47' may have a form like that of 
the row electrodes 42 of the panel 11 being formed with larger holes 
therethrough. In each case, the electrode with the small holes is the 
forward-most electrode, is supplied with a higher voltage, forms the anode 
of the plasma sac and carries the majority of the sac current. 
It is again noted that dimensions as specifically set forth herein as well 
as examples of numbers of sections, numbers of columns in each section, 
numbers of video drivers for each section, numbers of rows, operating 
voltages and other parameters are set forth by way of illustrative example 
and are not to be construed as limitations. 
It will be understood that modifications and variations may be effected 
without departing from the spirit and scope of the novel concepts of this 
invention.