JP3044805B2 - Image display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device for driving an electro-optical material layer using plasma to select pixels.

[0002]

2. Description of the Related Art For example, as a means for increasing the resolution and contrast of a liquid crystal display, a method of providing an active element such as a transistor for each display pixel and driving it (a so-called active matrix addressing method) is known. Generally done. However, in this case,
Since it is necessary to provide a large number of semiconductor elements such as thin film transistors, there is a concern about the yield problem, especially when the area is increased, and there is a serious problem that the cost is increased.

In order to solve this problem, Buzak et al. In Japanese Patent Application Laid-Open No. 1-217396 propose a method in which a discharge plasma is used as an active element instead of a semiconductor element such as a MOS transistor or a thin film transistor. Hereinafter, the configuration of an image display device that drives liquid crystal using discharge plasma will be briefly described.

This image display device is called a plasma-addressed liquid crystal display device (PALC).
As shown in FIG. 5, a liquid crystal layer 101 which is an electro-optical material layer,
The plasma chamber 102 is disposed adjacent to the plasma chamber 102 via a thin dielectric sheet 103 made of glass or the like. The plasma chamber 102 is formed by forming a plurality of grooves 105 parallel to each other in a glass substrate 104,
An ionizable gas is sealed therein. Each groove 105 has a pair of electrodes 106 parallel to each other.
107 is provided, and these electrodes 106 and 107 function as an anode and a cathode for ionizing gas in the plasma chamber 102 to generate discharge plasma. On the other hand, the liquid crystal layer 101 includes the dielectric sheet 103.
A transparent electrode 109 is formed on the surface of the transparent substrate 108 on the liquid crystal layer 101 side. The transparent electrode 109 is provided in the groove 105.
Perpendicular to the plasma chamber 102 constituted by
Intersections between the transparent electrode 109 and the plasma chamber 102 correspond to each pixel.

In the above-described image display apparatus, the plasma chamber 102 in which plasma discharge is performed is sequentially switched and scanned, and a signal voltage is applied to the transparent electrode 109 on the liquid crystal layer 101 side in synchronization with the scanning. Is held in each pixel, and the liquid crystal layer 101 is driven. Therefore, each groove 105, that is, each plasma chamber 102 corresponds to one scanning line, and the discharge region is divided for each scanning unit.

[0006]

By the way, it is considered that an image display device using discharge plasma can be easily made larger in area than a device using a semiconductor element as described above. Various problems remain. For example, since a voltage corresponding to each pixel is applied to the liquid crystal layer 101 via the dielectric sheet 103, there is a problem that crosstalk between the transparent electrodes 109 corresponding to display electrodes increases. Therefore, the present invention has been proposed to solve the problems of the related art, and an object of the present invention is to provide an image display device with less crosstalk, a large screen, and excellent display quality.

[0007]

In order to achieve the above object, an image display device according to the present invention comprises a first substrate having a first electrode which is a solid electrode on one principal surface; A second substrate having a second electrode, wherein the first substrate and the second substrate are arranged substantially parallel to each other so that the first electrode and the second electrode face each other, and the first substrate An electro-optic material layer is interposed so as to be in contact with the first electrode, and a dielectric sheet is disposed on the second substrate side of the electro-optic material layer, between the dielectric sheet and the second substrate. An ionizable gas is sealed to form a discharge region, and the second electrode comprises an anode electrode and a cathode electrode orthogonal to the anode electrode.
It is characterized in that it is a Y matrix electrode. Further, on / off of discharge plasma is controlled by the cathode electrode of the second electrode, and a voltage for driving an electro-optic material layer is applied to the anode electrode.

[0008]

In the image display device of the present invention, the anode electrode and the cathode electrode are orthogonally arranged to form an XY matrix electrode, and the intersection of the anode electrode and the cathode electrode corresponds to each pixel. Here, the cathode electrode controls on / off of discharge, and a voltage for driving the electro-optic material layer is applied to the anode electrode. That is, discharge plasma is locally generated corresponding to each pixel, and an analog voltage applied to the electro-optic material layer when the discharge is turned on is also controlled on the anode electrode side. Therefore, cross talk between display electrodes peculiar to PALC caused by the presence of the dielectric sheet is reduced.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 1, the image display device according to the present embodiment includes an electro-optical material between a flat and optically sufficiently transparent first substrate 1 and a flat and transparent second substrate 2. The liquid crystal layer 3 serving as a layer is interposed, and a space between the liquid crystal layer 3 and the second substrate 2 serves as a discharge region 4. These substrates 1,
2 is made of a non-conductive and optically transparent material here, but this is in consideration of a transmissive display device. It is only necessary that one of the substrates is transparent.

On the first substrate 1, a transparent electrode 5 is formed on one principal surface 1a, and a liquid crystal layer 3 made of a nematic liquid crystal or the like is arranged in contact with the electrode 5.
Here, the transparent electrode 5 is made of indium tin oxide (ITO) or the like, and has one main surface 1 of the first substrate 1.
The electrode is continuously formed on the entire surface of a, and is a so-called solid electrode. The liquid crystal layer 3 is made of glass, mica,
The first substrate 1 is sandwiched between the first substrate 1 and a thin dielectric film 6 made of plastic or the like.
The liquid crystal layer 3 and the dielectric film 6 form a so-called liquid crystal cell. The dielectric film 6 functions as an insulating barrier between the liquid crystal layer 3 and the discharge region 4. Without the dielectric film 6, the liquid crystal material flows into the discharge region 4 or the gas in the discharge region 4 causes the liquid crystal material to flow. The material may be contaminated. However, when a solid or encapsulated electro-optic material or the like is used instead of the liquid crystal material, it may not be necessary. In addition, the dielectric film 6 itself functions as a capacitor because it is formed of a dielectric material. Therefore, in order to sufficiently secure electrical coupling between the discharge region 4 and the liquid crystal layer 3, the dielectric film 6 is as thin as possible. Better.

On the other hand, the second substrate 2 also has an XY discharge electrode.
It is formed as a matrix electrode and is arranged at a predetermined distance from the dielectric film 6 by sealing the periphery, so that the space between the second substrate 2 and the dielectric film 6 generates a discharge plasma. Region 4 is set.
The discharge electrode includes a cathode electrode K directly formed on the second substrate 2 made of glass, and an anode electrode A laminated on the cathode electrode K via a dielectric layer 7 made of glass or the like. Have been. Then, these cathode K and the anode electrode A, respectively cathodes _{K 1, K 2, K 3} , K 4, K 5 ··· and the anode _{A 1, A 2, A 3} , A 4, A 5 ·· , And are arranged so as to be orthogonal to each other as shown in FIG.

The discharge region 4 is provided with the cathode K
₁ , K ₂ , K ₃ , K ₄ , K ₅ ... And anodes A ₁ , A
Are separated by partition walls 8 formed by a printing method corresponding to the intersections of ₂ , A ₃ , A ₄ , A _5, ... That is, the partition walls 8 are also formed vertically and horizontally like the XY matrix electrodes, and the cathodes K ₁ , K ₂ , K ₃ ,
K _4, K ₅ ··· and the anode _{A 1, A 2, A 3} , A 4,
The intersection of A ₅ ··· are arranged. Therefore, each plasma chamber P corresponds to one pixel. In addition,
Each plasma chamber P is filled with an ionizable gas. As the ionizable gas, helium, neon, argon, or a mixed gas thereof is used.

The partition 8 is formed by a printing method, for example, by laminating and printing a glass paste a plurality of times by a screen printing method. here,
The partition walls 8 also serve to regulate the gap interval W between the discharge regions 4, and this can be controlled by adjusting the number of times of screen printing, the amount of glass paste at each printing, and the like. Usually, it is about 200 μm. Further, the cathode electrode K and the anode electrode A also
For example, it can be formed by printing a conductive paste containing Ag powder or the like. Of course, it may be formed by an etching process, but in any case, it can be formed on a flat surface, so that it can be formed easily and dimensional accuracy such as electrode spacing can be ensured.

In the image display device having the above configuration, the liquid crystal layer 3 functions as a sampling capacitor,
An image is displayed by the discharge plasma generated in each plasma chamber P functioning as a sampling switch. Hereinafter, the display operation of the image display device of the present embodiment will be described. First, each of the cathodes K ₁ , K ₂ , K ₃ , K ₄ , K ₅
Are turned on line by line in a line-sequential manner, and a voltage (for example, -200 V) sufficient for starting discharge is applied. Other cathode lines are off (for example, 0 V).
On the other hand, each anode A ₁ , A ₂ , A ₃ , A ₄ , A _5.
Are turned on cathodes K ₁ , K ₂ , K ₃ , K ₄ , K
Analog voltages are simultaneously applied corresponding to ₅ . This analog voltage is in a range of about ± 40 Vpp, and selects ON / OFF of each pixel. That is, when both the cathode electrode K and the anode electrode A are turned on, discharge plasma is generated in the plasma chamber P, and the sampling switch is turned on. In the pixel corresponding to the plasma chamber P, the dielectric film 6 , A voltage is applied to the transparent electrode 5 on the liquid crystal layer 3 side. For example, if the transparent electrode 5 is set to 0V, the anode voltage (±) is applied to the selected pixel in which both the cathode electrode K and the anode electrode A are turned on.
(40 Vpp) is applied as it is, charges are stored in the liquid crystal layer 3 corresponding to the sampling capacitor, and the liquid crystal layer 3 is turned on.

The display operation of the image display apparatus according to the present embodiment has been described above. The characteristic feature of the display operation is that the anode electrode A and the cathode electrode K arranged on the discharge region side turn on / off the local plasma discharge. Off means that the analog voltage applied to each pixel is controlled. by this,
It is possible to significantly reduce cross talk between display electrodes peculiar to PALC caused by the presence of the dielectric sheet. Further, since the transparent electrode 5 on the liquid crystal layer 3 side may be a solid electrode, it is very advantageous in manufacturing. Further, a metal material or the like having a high conductivity can be used for any of the electrodes on the discharge region side, and the problem of wiring resistance when the size is increased can be avoided. Further, since the dielectric layer 7 is formed on the cathode electrode K, the dielectric layer 7 serves as a protective film to protect the cathode electrode K from ion sputtering, which is advantageous in terms of life.

Although specific embodiments to which the present invention is applied have been described above, the present invention is not limited to these embodiments, and materials, shapes, dimensions, and the like are arbitrary. Further, in the above-described embodiment, the partition walls are formed by printing corresponding to the intersections of the XY matrix electrodes. However, for example, the partition walls may be formed for each scanning line corresponding to the cathode electrode. Does not need to form a partition at all.

[0017]

As is apparent from the above description, in the present invention, the electrodes in the discharge region are XY matrix electrodes, and the XY matrix electrodes are used to turn on / off the discharge and to drive the electro-optical material layer. Since voltage is applied, crosstalk can be significantly reduced, and an image display device with a large screen and excellent display quality can be provided. Further, the image display device of the present invention is easy to manufacture, and is advantageous in terms of life and the like.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of an image display device to which the present invention is applied.

FIG. 2 is a main part schematic plan view schematically showing an arrangement state of XY matrix electrodes and partition walls.

FIG. 3 is a schematic perspective view showing an example of a conventional image display device with a part cut away.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... 1st board | substrate 2 ... 2nd board | substrate 3 ... Liquid crystal layer (electro-optic material layer) 4 ... Discharge area 5 ... Transparent electrode K ... Cathode electrode A ... Anode electrode 8: Partition wall

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ identification symbol FI // G09G 3/28 G09G 3/28 Z (58) Investigated field (Int.Cl. ⁷ , DB name) G02F 1/1333 G02F 1/133 G02F 1/1343 G09F 9/30 G09G 3/36 G09G 3/28

Claims (2)

(57) [Claims] A first electrode which is a solid electrode on one principal surface;
A first substrate and a second substrate having a second electrode on one main surface, and the first substrate and the second substrate are substantially parallel to each other such that the first electrode and the second electrode face each other. And an electro-optic material that is in contact with the first electrode of the first substrate.
A second layer of the electro-optic material layer
A dielectric sheet is arranged on the substrate side.
Discharge occurs when ionizable gas is sealed between the second substrates
An image display device , wherein the second electrode is an XY matrix electrode including an anode electrode and a cathode electrode orthogonal to the anode electrode. 2. The method according to claim 1, wherein on / off of discharge plasma is controlled by a cathode electrode of said second electrode, and a voltage for driving an electro-optic material layer is applied to said anode electrode. The image display device as described in the above.