JPH05303087A - Plasma address electro-optical device - Google Patents

Abstract

PURPOSE:To realize low power consumption and high speed driving of the plasma address electro-optical device. CONSTITUTION:A liquid crystal layer 6 is existed between a glass substrate 4 on the upper side and a glass substrate 7 on the lower side. Plural signal electrodes D arranged in parallel to each other are formed on the inner surface of the upper side glass substrate 4. Also plural plasma electrodes 8 arranged so as to be orthogonally intersecting and opposed to the signal electrodes D are formed on the inner surface of the lower side glass substrate 7. A plasma chamber 13 sealed with ionizeable gas is provided between the liquid crystal layer 6 and the lower side glass substrate 7, through an intermediate plate 3. The plasma chamber 13 is partitioned off by a bulkhead 9 provided along the plasma electrode 8, but communicates with each other through a notch provided partially. On the outside of the plasma electrode 8, at least a pair of discharge auxiliary electrodes 10 are provided so as to assist or induce a discharge starting by the plasma electrode 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma addressed electro-optical device having a two-layer structure of an electro-optical cell such as a liquid crystal cell and a switching plasma cell. More specifically, it relates to the structure of the discharge electrode provided in the plasma cell.

[0002]

2. Description of the Related Art Conventionally, a switching element such as a thin film transistor is provided for each pixel as a means for improving the resolution and contrast of a matrix type electro-optical device using a liquid crystal cell as an electro-optical cell, that is, a liquid crystal display device. A generally known active matrix addressing system is one in which a pixel is provided and is driven line-sequentially. However, in this case, it is necessary to provide a large number of semiconductor elements such as thin film transistors on the substrate, and there is a disadvantage that the manufacturing yield is deteriorated especially when the area is increased.

As a means for solving this disadvantage, Buzaku et al. Propose in Japanese Unexamined Patent Publication No. 1-217396 a method of using a plasma switch instead of a switching element such as a thin film transistor. Hereinafter, the configuration of the plasma addressed display device that drives the liquid crystal cell using the switch based on the plasma discharge will be briefly described.
As shown in FIG. 6, this device has a laminated flat panel structure including a liquid crystal cell 101, a plasma cell 102, and an intermediate plate 103 interposed therebetween. The plasma cell 102 is formed using a glass substrate 104, and a plurality of parallel grooves 105 are provided on the surface thereof. The groove 105 extends, for example, in the row direction of the matrix. Each groove 105 is sealed by an intermediate plate 103 and constitutes a plasma chamber 106 which is individually separated. The hermetically sealed plasma chamber 106 is filled with an ionizable gas. The individual plasma chambers 106 are completely airtightly separated and do not communicate with each other. The ridges 107 that separate the adjacent grooves 105 serve as partition walls that partition the individual plasma chambers 106, and also serve as gap spacers for the plasma chambers 106. Each groove 1
A pair of plasma electrodes 10 parallel to each other is provided on the bottom of 05.
8,109 are provided. The pair of electrodes function as an anode and a cathode, and ionize the gas in the plasma chamber 106 to generate discharge plasma. Such discharge regions are row scanning units and are individually separated.

On the other hand, the liquid crystal cell 101 is composed of a transparent substrate 110. The transparent substrate 110 is the intermediate plate 10.
3 are opposed to each other through a predetermined gap, and a liquid crystal layer 111 is filled in the gap. A signal electrode 112 made of a transparent conductive material is formed on the inner surface of the transparent substrate 110. The signal electrode 112 is orthogonal to the plasma chamber 106 and serves as a column drive unit. Matrix-shaped pixels are defined at the intersections of the column driving units and the row scanning units.

In the display device having such a structure,
Display driving is performed by line-sequentially switching and scanning the plasma chamber 106 in which plasma discharge is performed, and applying an image signal to the signal electrode 112 on the liquid crystal cell side in synchronization with this scanning. Individually separated plasma chamber 106
When plasma discharge is generated inside, the anode potential becomes substantially uniform inside, and pixel selection is performed for each row. That is, the plasma chamber 106 functions as a sampling switch.
When an image signal is applied to each pixel while the plasma sampling switch is in a conductive state, sampling hold is performed, and lighting or extinguishing of the pixel can be controlled. Even after the plasma sampling switch is turned off, the analog image signal is held in the pixel as it is.

[0006]

In order to generate plasma discharge or glow discharge in each plasma chamber, a discharge voltage is applied between a pair of electrodes, that is, an anode / cathode. Initially, a relatively high discharge starting voltage is required, and the subsequent discharge sustaining voltage can be relatively low. In the plasma cell structure shown in FIG. 6, individual plasma chambers are completely separated and independent, and a high discharge start voltage must be applied for each scanning unit. Therefore, there is a problem or a problem that the driving voltage of the plasma address electro-optical device becomes high and a large amount of power is consumed. Further, there is a statistical variation or delay from the application of the discharge start voltage to the actual occurrence of the glow discharge, which causes a problem that high-speed scanning of the discharge region is obstructed.

[0007]

SUMMARY OF THE INVENTION In view of the problems or problems of the above-mentioned conventional techniques, the present invention aims to reduce the power consumption and the driving speed of a plasma address electro-optical device. The following measures have been taken in order to achieve this object. That is, the plasma address electro-optical device according to the present invention,
A plurality of first members arranged in parallel with each other along a predetermined main surface
A first substrate having an electrode or a signal electrode, for example, a liquid crystal cell substrate, and a plurality of second electrodes or plasma electrodes arranged orthogonal to the signal electrode and parallel to each other, and the plasma electrode faces the signal electrode. It is composed of the second substrate or the plasma cell substrate arranged in this manner. An electro-optical material layer such as a liquid crystal layer is inserted between the liquid crystal cell substrate and the plasma cell substrate. A plasma chamber for enclosing an ionizable gas is formed between the liquid crystal layer and the plasma cell substrate. Further, the gas is selectively ionized by the discharge between the adjacent second electrodes, that is, between the anode / cathode, and the discharge region in which the ionized gas is localized is used as a scanning unit and is located at the intersection of the signal electrode and the discharge region. A means for driving the liquid crystal layer included in the pixel is provided. In this structure, at least a pair of discharge auxiliary electrodes are provided outside the plasma electrode facing the signal electrode, that is, other than the pixel portion, to assist in starting the discharge between the second electrodes. At this time, at least a pair of discharge induction electrodes may be interposed between the discharge auxiliary electrode and the second electrode.

More specifically, the partition wall is provided along the second electrode provided on the flat surface of the plasma cell substrate. The partition wall divides the plasma chamber into scan units. However, at least a part of each partition is removed, and the partitioned plasma chamber has a communication structure as a whole. The plasma discharge initiated by the action of the pair of discharge auxiliary electrodes is propagated in a chain through this communication structure, and the plasma discharge for each scanning unit is successively performed.

[0009]

According to the present invention, a pair of discharge auxiliary electrodes are provided, and glow discharge is constantly performed to maintain plasma particles. The plasma particles function as so-called ignition sources or triggers, and assist or induce the start of discharge in the adjacent plasma chambers. Once started, the glow discharge propagates through the communication structure of the plasma chamber and induces a discharge from the front stage side to the rear stage side. Therefore, the driving voltage applied between the anode and the cathode can be reduced, and at the same time, high-speed line-sequential scanning of the plasma discharge region can be performed except for statistical delay.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic sectional view showing an embodiment of a plasma address electro-optical device according to the present invention. This device has a structure in which a liquid crystal cell 1, a plasma cell 2, and a common intermediate plate 3 made of an extremely thin dielectric sheet interposed therebetween are laminated. The liquid crystal cell 1 is constructed by using an upper glass substrate 4, and a plurality of signal electrodes D made of a transparent conductive film are formed in parallel strips on the inner main surface thereof. The substrate 4 is adhered to the intermediate plate 3 using a spacer 5 with a predetermined gap. A liquid crystal layer 6, which is an electro-optical material layer, is filled in the gap. In this embodiment, a fluid electro-optical material is used, but the material is not limited to this. For example, an electro-optic crystal plate can be used. In this case, the intermediate plate 3 can be removed. Further, although the present embodiment relates to a plasma address display device, the present invention is not limited to this, and can be widely applied to plasma address electro-optical devices such as optical modulators.

On the other hand, the plasma cell 2 has a lower glass substrate 7
It is configured using. On the inner main surface of the glass substrate 7, a plurality of plasma electrodes 8 orthogonal to the signal electrodes D are formed in a strip shape. The plasma electrode 8 is thick-film printed on a flat surface of the glass substrate 7 by using a screen mask. The plasma electrodes 8 alternately function as the anodes A and the cathodes K, and the side wall surfaces of the electrodes face each other to form a parallel plate type discharge electrode structure. Plasma electrode 8 extending in the row direction and signal electrode D extending in the column direction
An effective display area P is defined at the intersection with and. A partition wall 9 is provided along each plasma electrode 8. This partition 9 is also formed by screen printing, for example, and has a laminated structure aligned with the plasma electrode 8. Effective display area P
At least a pair of discharge auxiliary electrodes 10 are provided outside and outside the plasma electrode group. This auxiliary electrode 10 has the same laminated structure as the plasma electrode 8 and functions as an anode Aa / cathode Ka. Auxiliary electrode 10
At least a pair of discharge induction electrodes 11 are provided between the plasma electrode 8 and the plasma electrode 8. The induction electrode 11 has the same laminated structure as the auxiliary electrode 10 and is located outside the effective display area P and functions as an anode Ab / cathode Kb. In some cases, the discharge induction electrode 11 may be omitted and the auxiliary discharge electrode 10 and the plasma electrode group 8 may be directly adjacent to each other. That is, the discharge induction electrode 11 functions as a dummy electrode.

The lower glass substrate 7 is a frit seal 12
Is bonded to the intermediate plate 3 by using. An airtightly sealed plasma chamber 13 is formed between the two. The plasma chamber 13 is divided or divided by partition walls 9 and individually constitutes a discharge region 14 which is a row scanning unit. Part of the individual barrier ribs 9 are removed, and the discharge regions 14 communicate with each other to form a so-called open cell structure. An ionizable gas is sealed inside the plasma chamber 13 which is airtight as a whole. The gas species can be selected from, for example, helium, neon, argon, xenon or a mixed gas thereof. A gas introduction path 15 is provided so as to penetrate the glass substrate 7. Plasma chamber 13 is introduced through this introduction path 15.
After being filled with ionizable gas, the opening of the gas introduction passage 15 is sealed by the protrusion 16. The protrusion 16 and the gas introduction path 15 are located outside the effective display area P.

Next, the operation of the auxiliary electrode 10 which is the main part of the present invention will be described with reference to FIG. FIG. 2 is a graph showing the relationship between the discharge voltage and the discharge current. The present invention utilizes the glow discharge region. As is clear from the graph, the discharge sustaining voltage VH is lower than the discharge starting voltage VS. Since it is necessary to generate charged particles at the start of discharge and high energy is required, the discharge start voltage VS is high. Once the ionized state is realized, the production of charged particles is maintained in a chain. By utilizing this fact, the plasma discharge starting voltage can be suppressed by allowing charged particles to exist in advance as a spark or a trigger. For this purpose, a pair of discharge auxiliary electrodes 10 are provided so that charged particles are held between the anode Aa and the cathode Ka to induce the subsequent plasma discharge. The discharge induction electrode 11 interposed between the discharge auxiliary electrode 10 and the plasma electrode 8 functions as a so-called bridge.

To facilitate understanding of the present invention, FIG. 3 shows a planar shape of the plasma addressed electro-optical device. As shown in the figure, the pair of glass substrates 4 and 7 are fixed to each other by a frit seal 12, and a plasma chamber 13 that is hermetically sealed is formed inside. A gas introduction path 15 and a protrusion 16 are provided outside the upper effective display area of the plasma chamber 13. The pair of discharge auxiliary electrodes 10 are provided adjacent to the gas introduction path 15 and are also located outside the effective display area.
Since a voltage is constantly applied to the pair of auxiliary electrodes and there is a risk of deterioration, they are arranged outside the effective display area. Further, in order to improve reliability, two or more sets of discharge auxiliary electrodes may be provided in parallel. At least a pair of discharge inducing electrodes 11 are interposed between the discharge auxiliary electrode 10 and the plasma electrode group 8 in parallel with both. This induction electrode is inserted in order to keep the auxiliary electrode, which constantly emits light, away from the effective display area. The induction electrode 11 is selected prior to the line-sequential scanning of the plasma electrode group 8. One ends of the auxiliary electrode 10, the induction electrode 11 and the plasma electrode 8 are removed together with the partition wall, and the plasma chamber 13 has a communication structure as a whole. Charged particles leak from the removed part of the partition wall and induce plasma discharge from the preceding stage to the succeeding stage. Therefore, the drive voltage applied to each plasma electrode 8 can be set to a low level. Since the auxiliary discharge electrode 10 is provided in the vicinity of the gas introduction path 15 and the sealing protrusion 16, the area outside the effective display area can be efficiently utilized.

Next, the line sequential scanning of the plasma addressed electro-optical device will be described with reference to FIG. FIG. 4 shows an example of a drive circuit used in this device. This drive circuit is composed of a signal circuit 21, a scanning circuit 22, and a control circuit 23. The signal electrodes D1 to Dm are connected to the signal circuit 21 via buffers. On the other hand, in the scanning circuit 22, the cathode K of the plasma electrode group is also passed through the buffer.
1 to Kn are connected. In addition, the cathode Ka of the discharge auxiliary electrode and the cathode Kb of the discharge inducing electrode are also connected to the scanning circuit 2
Connected to 2. On the other hand, all the anodes A are commonly grounded. The cathodes K1 to Kn are line-sequentially scanned by the scanning circuit 22, and the signal circuit 21 supplies a drive voltage to each of the signal electrodes D1 to Dm in synchronization with this. The cathode Kb of the discharge induction electrode is selected at the beginning of line-sequential scanning. Further, a voltage for sustaining plasma discharge is continuously applied to the cathode Ka of the discharge auxiliary electrode after the device is started. The control circuit 23 controls synchronization of the signal circuit 21 and the scanning circuit 22. A plasma discharge region is formed along each of the cathodes K1 to Kn and serves as a row scanning unit.
On the other hand, each of the signal electrodes D1 to Dm serves as a column driving unit. A pixel 24 is defined between both units. Since the anodes are commonly grounded, the pixel 24 is formed between the anodes located on both sides of each cathode. The driving method is not limited to this, and the anodes may be individually driven separately.

Finally, FIG. 5 is a schematic view showing the pixel 24 shown in FIG. A pair of plasma electrodes arranged adjacent to each other on the lower glass substrate functions as, for example, an anode A1 and a cathode K1. The anode /
A voltage is applied between the cathodes to cause plasma discharge.
At this time, the potential on the back surface side of the intermediate plate 3 is fixed to substantially the anode potential due to the characteristics of plasma discharge. That is, the discharge region functions as the plasma switch S1. It goes without saying that the potential on the back surface side of the intermediate plate 3 in the portion where plasma discharge is not performed is indefinite or open. The strip-shaped plasma discharge region or plasma generation site can be sequentially scanned by sequentially switching the adjacent electrode pairs to which a voltage is applied, that is, the anode / cathode, between the adjacent electrodes by an external scanning circuit. At the plasma generation site of a specific scanning unit, when a driving voltage is applied to the signal electrodes D1, D2, ... Provided on the upper glass substrate within the period in which plasma is generated and scanning is subsequently switched, immediately before scanning switching Plasma generation part and each signal electrode D1, D2, ...
Accumulation of electric charges occurs in the area overlapping with. Since the plasma disappears immediately after switching the scanning, the potential on the back surface side of the intermediate plate 3 becomes indefinite, and the accumulated charges are not affected by the drive voltage supplied to the signal electrode, and the predetermined controlled charges remain unchanged. maintain. The maintenance of this charge continues until the region is scanned next and plasma generation occurs. An electric field is applied to the liquid crystal layer 6 by the accumulated charges and the liquid crystal molecule alignment is changed. The change in the liquid crystal molecule arrangement can be changed to the change in the amount of transmitted light by combining an appropriate optical element. In this way, an image can be displayed by controlling the charge amount of each pixel by the external circuit.

[0017]

As described above, according to the present invention, at least a pair of discharge auxiliary electrodes are provided outside the effective operation area of the plasma address electro-optical device, and a part of the partition wall for partitioning the sealed plasma chamber is formed. It was removed so that plasma particles could leak into the adjacent compartments. With such a structure, the start of line-sequential plasma discharge is assisted or induced to lower the drive voltage, which has the effect of contributing to the reduction of power consumption. Further, there is an effect that a statistical delay from the application of the drive voltage to the actual generation of plasma discharge can be reduced and high speed scanning can be performed. Thus, there is an effect that stable and reliable plasma discharge can be realized.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a basic structure of a plasma address electro-optical device according to the present invention.

FIG. 2 is a graph for explaining the function of a discharge auxiliary electrode adopted in the present invention.

FIG. 3 is a schematic plan view of a plasma address electro-optical device according to the present invention.

FIG. 4 is a drive circuit diagram of a plasma address electro-optical device according to the present invention.

FIG. 5 is a schematic view showing a pixel included in a plasma addressed electro-optical device according to the present invention by cutting out a pixel.

FIG. 6 is a perspective view showing an example of a conventional plasma address electro-optical device.

[Explanation of symbols]

 1 Liquid Crystal Cell 2 Plasma Cell 3 Intermediate Plate 4 Glass Substrate 6 Liquid Crystal Layer 7 Glass Substrate 8 Plasma Electrode 9 Partition Wall 10 Discharge Auxiliary Electrode 11 Discharge Inducing Electrode 12 Frit Seal 13 Plasma Chamber 14 Discharge Area 15 Gas Inlet Channel 16 Sealing Protrusion A Anode K cathode D signal electrode P effective display area

Claims (3)

[Claims] 1. A first substrate having a plurality of first electrodes arranged parallel to each other along a predetermined main surface, and a plurality of second electrodes orthogonal to the first electrodes and arranged parallel to each other. And a second substrate having the second electrode arranged so as to face the first electrode, an electro-optical material layer interposed between the first and second substrates, and the electro-optical material. A plasma chamber for enclosing the ionizable gas formed between the layer and the second substrate, and the discharge between the adjacent second electrodes to selectively ionize the gas, and the localized discharge of the ionized gas A means for driving the electro-optical material layer located at the intersection of the first electrode and the discharge area with the area as a scanning unit is provided, and at least one pair of discharge auxiliary electrodes is provided outside the second electrode facing the first electrode. Is provided to assist in starting discharge between the second electrodes A plasma address electro-optical device having the above-mentioned configuration. 2. The plasma addressed electro-optical device according to claim 1, further comprising at least one pair of discharge induction electrodes interposed between the discharge auxiliary electrode and the second electrode. 3. A first substrate having a plurality of first electrodes arranged parallel to each other along a predetermined main surface, and a plurality of second electrodes orthogonal to the first electrodes and arranged parallel to each other. And a second substrate having a partition wall formed on the second electrode, the second electrode being arranged so as to face the first electrode, and interposed between the first and second substrates. The electro-optical material layer, a plasma chamber partitioned by the partition wall for enclosing an ionizable gas between the electro-optical material layer and the second substrate, and the discharge between the adjacent second electrodes A means for selectively ionizing the gas and driving an electro-optical material layer located at the intersection of the first electrode and the discharge area with the discharge area where the ionized gas is localized as a scanning unit; At least one pair outside the opposing second electrodes And a plasma address electro-optical device, wherein at least a part of each of the partition walls is removed and the plasma chamber has a communication structure.