An electro-optical device applied as an image display device includes a first substrate having a plurality of non-overlapping first electrodes on a major surface thereof; and a second substrate opposed to the first substrate and having a plurality of non-overlapping second electrodes on a major surface thereof wherein the second electrodes are disposed substantially perpendicular to the first electrodes. This device further includes an electro-optical material layer disposed between the first and second electrodes; and a discharge chamber disposed between the electro-optical material layer and the second substrate, and filled with an ionizable gas, the discharge chamber having a plurality of scanning units, the scanning units being divided by partition walls formed by a printing process. By formation of grooves by the printing process, the difficult process of etching of grooves or formation of electrodes in the grooves is unnecessary, and the manufacturing is easy. This is advantageous to implementation of large display screens or miniaturization.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an electro-optical device in an image display 
adapted to drive an electro-optic material layer which uses plasma to 
select pixels. 
2. Description of the Related Art 
As the means for providing, for example, a liquid crystal display with high 
resolution and high contrast, there is generally provided active elements, 
such as transistors, etc. to drive every display pixel (which is referred 
to as an active matrix addressing system). 
In this case, however, since it is necessary to provide a large number of 
semiconductor elements such as thin film transistors, the problem of yield 
results particularly when the display area is enlarged, giving rise to the 
great problem that the cost is necessarily increased. 
Thus, as the means for solving this, Buzak et al. have proposed in the 
Japanese Laid Open Application No. 217396/89 publication a method 
utilizing discharge plasma in place of semiconductor elements such as MOS 
transistors or thin film transistors, etc. as an active element. 
The configuration of an image display device for driving a liquid crystal 
by making use of discharge plasma will be briefly described below. 
This image display device is called a Plasma Addressed Liquid Crystal 
display device (C). As shown in FIG. 6 of the present drawings, a 
liquid crystal layer 101 serving as an electro-optic material layer and 
plasma chambers 102 are adjacently arranged on an opposite side of a thin 
dielectric sheet 103 comprised of glass, etc. 
The plasma chambers 102 are constituted by forming a plurality of grooves 
105 in parallel to each other in a glass substrate or base plate 104. 
These chambers are filled with an ionizable gas. Further, pairs of 
electrodes 106 and 107 are provided in the grooves 105 in parallel to each 
other. These electrodes 106 and 107 function as an anode and a cathode for 
ionizing the gas within the plasma chambers 102 to generate a discharge 
plasma. 
The liquid crystal portion of the display has the liquid crystal layer 101 
held between the dielectric sheet 103 and a transparent base plate 108. On 
the surface of the transparent base plate 108 at the liquid crystal layer 
101 side are formed transparent electrodes 109. These transparent 
electrodes 109 are perpendicular to the plasma chambers 102 constituted by 
the grooves 105. The locations where the transparent electrodes 109 and 
the plasma chambers 102 intersect with each other correspond to respective 
pixels. 
In the above-mentioned image display device, by switching and scanning the 
plasma chambers 102 in sequence where a plasma discharge is to be carried 
out, and applying signal voltages to the transparent electrodes 109 on the 
liquid crystal layer 101 side in synchronism with the switching scan 
operation, these signal voltages are held by respective pixels. The liquid 
crystal layer 101 is thus driven. 
Accordingly, the grooves 105, i.e., plasma chambers 102 respectively 
correspond to one scanning line, and the discharge region is divided every 
scanning unit. 
In image display devices utilizing discharge plasma as described above, an 
enlarged display area is more easily realized than larger areas utilizing 
semiconductor elements, but various problems arise in putting such a 
device into practice. 
For example, forming the grooves 105 which constitute the plasma chambers 
102 on the transparent glass substrate 104 raises considerable 
manufacturing problems. In particular, it is extremely difficult to form 
such grooves at a high density. 
Further, it is required to form the electrodes 106 and 107 which generate 
the discharge in the grooves 105. However, an etching process which form 
the electrodes is troublesome, and it is difficult to maintain the spacing 
between electrodes 106 and 107 accurately. 
SUMMARY OF THE INVENTION 
With the above-mentioned problems with such prior arts in view, the present 
invention has been proposed, and its object is to provide an 
electro-optical device applied as an image display device that is simple 
to manufacture and suitable for implementation as a large display surface 
and with highly miniaturized components. 
To attain the above-described and other objects, there is provided in 
accordance with this invention an electro-optical device comprising: a 
first substrate having a plurality of non-overlapping first electrodes on 
a major surface thereof; a second substrate opposed to the first substrate 
and having a plurality of non-overlapping second electrodes on a major 
surface thereof, the second electrodes being disposed substantially 
perpendicular to the first electrodes; an electro-optical material layer 
disposed between the first and second electrodes; and a discharge chamber 
disposed between the electro-optical material layer and the second 
substrate, and filled with an ionizable gas, the discharge chamber having 
a plurality of scanning units, the scanning units being divided by 
partition walls formed by printing. 
There may be also provided an addressing structure comprising: a substrate 
having a plurality of electrodes on a major surface thereof; a dielectric 
material layer opposed to the substrate; and an ionizable gas filled 
between the substrate and the dielectric material layer, the ionizable gas 
defining a discharge region which provides scanning units divided by 
partition walls formed by printing. 
In the image display device of this invention, partition walls dividing the 
discharge area every scanning unit are formed by the printing process. The 
printing process is a very simple technique, and permits formation of a 
fine pattern. Thus, the productivity and/or working efficiency can be 
improved to a higher degree as compared to the groove forming method. 
Further, since the second electrodes for discharge are formed on a flat 
substrate, etching process is also simple, and the distance between 
electrodes can be controlled with high accuracy.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
An actual embodiment to which this invention is applied will now be 
described in detail with reference to the attached drawings. 
An embodiment of an image display device is shown in FIG. 1, in which a 
liquid crystal layer 3 serving as an electro-optic material layer is 
provided between a flat and optically sufficiently transparent first 
substrate 1 and a similarly flat and transparent second substrate 2. A 
space between the liquid crystal layer 3 and the second base plate 2 is 
utilized as a discharge chamber 4. 
Here, these base plates 1 and 2 are both formed of a non-conductive and 
optically transparent material since the image display device in this 
embodiment is of the transmission type. However, in the case where the 
image display device is a direct-viewing or reflection type display 
device, it is sufficient that only one base plate is transparent. 
Strip-shaped electrodes 5 are formed on one major surface 1a of the first 
substrate 1, and a liquid crystal layer 3 comprised of a nematic liquid 
crystal, etc. is arranged in contact with the electrodes 5. This liquid 
crystal layer 3 is held between a thin dielectric film 6 comprised of 
glass, mica, or plastic, etc. and the first base plate 1. There is thus 
provided a configuration in which so called liquid crystal cells are 
constituted by the first base plate 1, the liquid crystal layer 3, and the 
dielectric film 6. 
The above-mentioned dielectric film 6 functions as an insulating shield 
layer between the liquid crystal layer 3 and the discharge chamber 4. If 
there is no dielectric film 6, there is the possibility that the liquid 
crystal material may flow into any discharge chamber 4, or the liquid 
crystal material may be polluted by gas from the discharge chamber 4. It 
is to be noted that where a solid-state or encapsulated electro-optic 
material, etc. is used in place of the liquid crystal material, such a 
dielectric film 6 may not be required. 
In addition, since the dielectric film 6 is formed by dielectric material, 
the dielectric film 6 itself also functions as a capacitor. Accordingly, 
in order to ensure sufficient electric coupling between the discharge 
chamber 4 and the liquid crystal layer 3 and to suppress two-dimensional 
diffusion of charges, it is desirable that the dielectric film 6 be as 
thin as possible. 
Discharge electrode groups 7 are formed as a strip-shaped electrodes on the 
second substrate 2. Peripheral portions of the second substrate 2 are 
supported by sealing spacer members 8, at a predetermined spacing from the 
dielectric film 6. Thus, a space is formed between the second substrate 2 
and the dielectric film 6 serves as a discharge chamber or region in which 
the discharge plasma is generated. 
This discharge chamber 4 is partitioned by partition walls 9 by the 
printing process to provide respective independent plasma chambers 
P.sub.1, P.sub.2, P.sub.3, . . . P.sub.n. 
Ionizable gas is filled into respective plasma chambers P.sub.1, P.sub.2, 
P.sub.3, . . . P.sub.n. As the ionizable gas, helium, neon, argon, or a 
mixture of such gases may be used. 
The above-mentioned partition walls 9 are formed in parallel to the 
respective strip-shaped electrodes of the discharge electrode groups 7, 
and in the gaps between these strip-shaped electrodes. In this embodiment, 
the partition walls are provided between every respective pair of an anode 
and a cathode which will be described later. Each anode and cathode pair 
make up a scanning unit. Accordingly, these plasma chambers P.sub.1, 
P.sub.2, P.sub.3, . . . P.sub.n correspond to respective scanning lines. 
The partition walls 9 are formed by printing process. In particular, the 
partitions are formed by laminate-printing, e.g., with a glass paste many 
times in a screen printing process. Here, the partition walls 9 function 
to limit a gap interval W of the discharge chamber 4 (i.e., the distance 
between the second substrate 2 and the dielectric film 6). This is 
controlled by adjusting the number of screen printings. Ordinarily, the 
gap width W is about 200 .mu.m. 
Further, discharge electrode groups 7 in respective plasma chambers 
P.sub.1, P.sub.2, P.sub.3, . . . P.sub.n can be directly formed on the 
second substrate. For example, the electrode groups may be formed by 
printing on the substrate with a conductive paste including Ag powder, 
etc. Of course, the electrode groups may instead be formed by an etching 
process. Since the electrodes are being formed on a flat planer surface, 
they can be formed by nearly any process with ease. In addition, the 
dimensional accuracy of the electrode interval, etc.; can be ensured. 
Accordingly, in manufacturing, discharge electrode groups 7 are first 
formed on the flat second substrate 2, and partition walls 9 are then 
formed by the printing process. 
The overall configuration of the image display device has been described as 
above. In greater detail, the electrodes for driving the liquid crystal 
layer 3 are formed on the base plates 1 and 2, respectively. The 
configuration of these electrodes will now be described. 
On the principal surface 1a of the first substrate 1 which lies opposite to 
the second substrate 2, a plurality of strip-shaped electrodes 5 having a 
predetermined width are formed. These electrodes 5 are formed of a 
transparent conductive material, e.g., Indium Tin Oxide (ITO), etc., and 
are optically transparent. Further, electrodes 5 are arranged in parallel 
to each other as can be better seen in FIG. 2 and are arranged 
perpendicularly to, for example, the display surface. 
On the principal surface 2a of the second base plate 2 which lies opposite 
to the first base plate 1, groups of discharge electrodes 7 are similarly 
formed. These discharge electrode groups 7 are also parallel linear 
electrodes, but they are arranged in a direction perpendicular to the 
electrodes 5 formed on the first substrate 1. Namely, these discharge 
electrode groups 7 are arranged in a horizontal direction on the screen, 
while the electrodes 5 are in a vertical direction. More particularly, 
these discharge electrode groups 7 are comprised of anode electrodes 
A.sub.1, A.sub.2, A.sub.3. . . A.sub.n-1, A.sub.n and cathode electrodes 
K.sub.1, K.sub.2, K.sub.3, . . . K.sub.n-1, K.sub.n. By pairing these 
electrodes, respective discharge electrodes are provided. The discharge 
electrodes 7 are disposed within respective plasma chambers P.sub.1, 
P.sub.2, P.sub.3, . . . P.sub.n. 
The relative arrangement of the electrodes 5 formed on the first substrate 
1 and the discharge electrode groups 7 formed on the second base plate 2 
is shown in a schematic diagram in FIG. 2. 
Here, a first signal application means that comprises a data driver circuit 
10 and output amplifiers 11 is connected to the electrodes 5 on the first 
substrate 1. Analog voltages from the respective output amplifiers 11 are 
delivered as liquid crystal drive signals. 
Second signal application means that comprises a data strobe circuit 12 and 
output amplifiers 13 is connected to respective cathode electrodes 
K.sub.1, K.sub.2, K.sub.3, . . . K.sub.n-1, K.sub.n, of the discharge 
electrode group 7 on the second substrate 2. Pulse voltages from the 
respective output amplifiers 12 are delivered as data strobe signals, 
respectively. In addition, a common reference voltage (which is ground 
voltage in the present embodiment) is applied to the respective anode 
electrodes A.sub.1, A.sub.2, A.sub.3. . . A.sub.n-1, A.sub.n. 
The connection structure of the discharge electrode groups 7 formed on the 
second substrate 2 is as shown in FIG. 3. 
To form an image over the entirety of the display screen, there is provided 
a scanning control circuit 14 connected to the data driver circuit 10 and 
the data strobe circuit 12. This scanning control circuit 14 serves to 
control or regulate the functions of the data driver circuit 10 and the 
data strobe circuit 12 to carry out sequential addressing from row to row 
with respect to all pixel trains of the liquid crystal layer 3. 
In the image display device constructed as described above, the liquid 
crystal layer 3 functions as a sampling capacitor for analog voltages 
applied to the electrodes 5 formed on the first substrate 1, and the 
discharge plasma generated in the discharge chamber 4 functions as a 
sampling switch. Thus, an image is displayed. 
The diagram for explaining the image display operation is shown in FIG. 4. 
In FIG. 4, the liquid crystal layer 3 corresponding to respective pixels 
can be understood as capacitors 15 in an equivalent circuit. Namely, the 
capacitors 15 indicate capacitive liquid crystal cells formed at the 
portions where the electrodes 5 and respective plasma chambers P.sub.1, 
P.sub.2, P.sub.3, . . . P.sub.n overlap with each other. 
It is now assumed that analog voltages are applied to the respective 
electrodes 5 by the data driver circuit 10. Here, assuming that no data 
strobe signal (pulse voltage) is applied to the cathode electrode K.sub.1 
of the second substrate 2, i.e., the cathode electrode K.sub.1 is in an 
OFF state, so that no discharge is produced by the anode electrode A.sub.1 
and the cathode electrode K.sub.1. As a result, gas in the vicinity 
thereof is in a non-ionized state. Accordingly, the plasma switch S.sub.1 
(the electrical connection of the electrode 5 and the anode electrode Al) 
is also in an OFF state. As a result, even if any analog voltage is 
applied to the electrodes 5, there is no change in the potential applied 
to the respective capacitors 15. 
On the other hand, if a data strobe signal is applied to the cathode 
electrode K2 of the second base plate 2, i.e. , the cathode electrode K2 
is in an ON state, gas is ionized by discharge between the anode electrode 
A.sub.2 and the cathode electrode K.sub.2, so an ionized region (plasma 
discharge) takes place within the plasma chamber P.sub.2 Thus, in the 
so-called plasma switching operation, the electrode 5 and the anode 
electrode A.sub.2 are electrically connected. Namely, in the circuit 
operation, the plasma switch S.sub.2 is turned ON. 
As a result, an analog voltage delivered to the electrode 5 is stored in a 
capacitor 15 of the column where the cathode electrode K.sub.2 is in a 
strobe state. Even after the strobe or pulse to the cathode electrode 
K.sub.2 is completed, no discharge plasma is dissipated or lost for a time 
period until next strobe is carried out (during at least a field interval 
of that image), and this analog voltages remains in the state where it is 
stored in the respective capacitor 15. As a result, this analog voltages 
does not undergo the influence of changes at subsequent times of analog 
voltages applied to the electrodes 5. 
Accordingly, when an approach is employed to allow the cathode electrodes 
K.sub.1, K.sub.2, K.sub.3. . . K.sub.n-, K.sub.n to be subjected to 
sequential addressing to apply data strobe signals to the plasma chambers 
P.sub.1, P.sub.2, P.sub.3, . . . P.sub.n, and to apply at the same time 
liquid crystal drive signals as analog voltages to the respective 
electrodes 5 in synchronism with the application of the data strobe 
signals, the plasma switches function as active elements in the same 
manner as in the case of the semiconductor elements such as thin film 
transistors, etc. Thus, the liquid crystal layer 3 is driven in the same 
manner as in the case of the active matrix addressing system. 
It is to be noted that it is a matter of course that the drive system for 
an image display device is not limited to the above-described system. 
In the above-described embodiment, respective paired electrodes (an anode 
and a cathode) are arranged as a discharge electrode within the plasma 
chambers P.sub.1, P.sub.2, P.sub.3, . . . P.sub.n. In addition, by forming 
partition walls by the printing process, it is possible to increase the 
degree of the electrode position and the number of electrodes. 
Explanation will now be given in connection with an embodiment in which 
partition walls are formed on the electrode, thus to reduce the number of 
discharge electrodes by one half. 
Also in an electro-optical device applied to an image display device of the 
second embodiment, as shown in FIG. 5, between a first substrate 21 
including strip-shaped electrodes 23 formed thereon and a second substrate 
22 including discharge electrodes 24 formed thereon, a liquid crystal 
layer 25 serving as an electro-optical material layer is inserted. 
Further, a space between the dielectric film 26 and the second substrate 
22 is caused to serve as a discharge region 27. This configuration is 
similar to the corresponding above-described embodiment. 
This embodiment is characterized in that discharge electrodes 24 on the 
second substrate 22 are arranged at equal intervals, and that partition 
walls 28 are formed by the printing process on the respective discharge 
electrodes 24, whereby the discharge chamber is divided into respective 
plasma chambers P.sub.1, P.sub.2, P.sub.3, . . . P.sub.n. Such a 
configuration can be accomplished for the first time by print-forming 
partition walls 28 partitioning the discharge region 26. 
In the case where partition walls 28 are print-formed on the discharge 
electrode 24 in a manner as described above, in the respective plasma 
chambers p.sub.1, p.sub.2, p.sub.3, . . . p.sub.n partitioned by these 
partition walls 28, discharge electrodes 24 are commonly used. Namely, for 
example, the discharge electrode 24a serves as both a discharge electrode 
of one plasma chamber p.sub.1 and a discharge electrode of another plasma 
chamber p.sub.2. Similarly, the discharge electrode 24b serves as both a 
discharge electrode of the plasma chamber P.sub.2 and a discharge 
electrode of the plasma chamber P.sub.3. Accordingly, the number of 
electrodes can be reduced to one half. 
Further, since there is employed a structure such that partition walls 28 
which do not contribute to the display overlap the discharge electrodes 
24, the aperture or opening ratio can be improved, thus making it possible 
to improve the optical characteristics. 
It is to be noted that in the case where discharge electrodes 24 are 
arranged in such a manner that they are commonly used for adjacent plasma 
chambers, it is necessary to revise somewhat the drive system. For 
example, it is sufficient to adopt an approach to allow respective 
discharge electrodes 24 to serve as both anode and cathode to sequentially 
carry out switching between the anode and the cathode to allow the timings 
thereof to be in correspondence with each other to thereby sequentially 
carry out discharge at respective plasma chambers p.sub.1, p.sub.2, 
p.sub.3, . . . p.sub.n 
While explanation has been given in connection with the actual embodiments 
to which this invention is applied, this invention is not limited to such 
embodiments. Namely, the material, the shape and the dimensions, etc. are 
arbitrary. In addition, while, in the above-described embodiments, the 
partition walls are print-formed for every scanning unit, the partition 
walls may instead be formed every two or more scanning units. 
As is clear from the foregoing description, in accordance with this 
invention, that since partition walls dividing the discharge region are 
formed by the printing process, the difficult process of etching of 
grooves or formation of electrodes in the grooves is unnecessary, and the 
manufacturing is made easy. Further, this invention is advantageous for 
large display screens and high accuracy. 
In addition, in accordance with this invention, by allowing the discharge 
electrodes to be overlapped by the partition walls, the area occupied 
thereby is reduced. Thus, the aperture ratio is improved. Accordingly, the 
efficiency is improved. This is also advantageous to the optical 
characteristic. 
Although other modifications and changes may be suggested by those skilled 
in the art, it is the intention of the inventors to embody within the 
patent warranted hereon all changes and modifications as reasonably and 
properly come within the scope of their contribution to the art.