JPH04265932A - Image display device - Google Patents

Abstract

PURPOSE:To reduce crosstalk and obtain a large-sized screen by applying a voltage for turning ON and OFF discharge and a voltage for driving an electrooptic material by XY matrix electrodes. CONSTITUTION:On a 1st substrate 1, a transparent electrode 5 is formed and a liquid crystal layer 3 is arranged. On a 2nd substrate 2, on the other hand, the electrodes for discharging are formed as the XY matrix electrodes and arranged at specific intervals with a dielectric film 6 by sealing the periphery and the space between the 2nd substrate 2 and dielectric film 6 serves as a discharge area 4 where discharge plasma is generated. The discharging electrodes consist of cathode electrodes K formed directly on the 2nd substrate 2 and anode electrodes A laminated on the cathode electrodes K across a dielectric layer 7 and are arranged crossing each other to form the XY matrix electrodes. Then those electrodes A and K control the ON/OFF state of local plasma discharging and the analog voltages applied to respective picture elements.

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 that selects pixels by driving an electro-optic material layer using plasma.

0002

[Prior 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 the active element (so-called active matrix addressing method) is used.
is commonly practiced. 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 yield problems especially when the area is increased, and a big problem arises that the cost inevitably increases.

As a means to solve this problem, Buzak et al. proposed in Japanese Patent Application Laid-Open No. 1-217396 a method of using discharge plasma as an active element instead of a semiconductor element such as a MOS transistor or a thin film transistor. The configuration of an image display device that drives liquid crystal using discharge plasma will be briefly described below.

This image display device is called a plasma addressed liquid crystal display (PALC), and is shown in FIG.
As shown in FIG. 1, a liquid crystal layer 101 which is an electro-optic material layer,
A plasma chamber 102 is placed adjacent to the plasma chamber 102 with a thin dielectric sheet 103 made of glass or the like interposed therebetween. The plasma chamber 102 is constructed by forming a plurality of mutually parallel grooves 105 in a glass substrate 104, and an ionizable gas is sealed therein. Each groove 105 also has a pair of electrodes 106 parallel to each other.
, 107 are provided, and these electrodes 106, 107
functions as an anode and a cathode for ionizing gas in the plasma chamber 102 and generating discharge plasma. On the other hand, the liquid crystal layer 101 includes the dielectric sheet 103.
and a transparent substrate 108, and a transparent electrode 109 is formed on the surface of the transparent substrate 108 on the liquid crystal layer 101 side. This transparent electrode 109 is connected to the groove 105.
It is perpendicular to the plasma chamber 102 composed of
The intersection of these transparent electrodes 109 and the plasma chamber 102 corresponds to each pixel.

In the above-mentioned image display device, 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 this, thereby changing the signal voltage. 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 area is divided for each scanning unit.

[0006]

[Problems to be Solved by the Invention] By the way, as mentioned above, it is thought that image display devices using discharge plasma can be made larger in area more easily than those using semiconductor elements, but it is difficult to put them into practical use. 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 in that crosstalk between the transparent electrodes 109 corresponding to display electrodes increases. SUMMARY OF THE INVENTION The present invention was proposed to solve the problems of the conventional devices, 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]

Means for Solving the Problems In order to achieve the above object, an image display device of the present invention includes a first substrate having a first electrode on one main surface, and a second electrode on one main surface. the second with
the first substrate and the second substrate are connected to the first substrate.
An electrode and a second electrode are arranged substantially parallel to each other so as to face each other, an electro-optic material layer is interposed so as to be in contact with the first electrode of the first substrate, and the electro-optic material layer and the second electrode are interposed so as to be in contact with the first electrode of the first substrate. An ionizable gas is sealed in the space between the substrates to form a discharge region, and the second electrode is an XY matrix electrode consisting of an anode electrode and a cathode electrode orthogonal thereto. .

[0008]

In the image display device of the present invention, an anode electrode and a cathode electrode are arranged orthogonally to form an XY matrix electrode, and the intersection of these anode electrodes and cathode electrodes 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 generated locally corresponding to each pixel, and the analog voltage applied to the electro-optic material layer when the discharge is turned on is also controlled on the anode electrode side. Therefore, crosstalk between display electrodes, which is unique to PALC and occurs due to the presence of the dielectric sheet, is reduced.

[0009]

Embodiments Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. As shown in FIG. 1, the image display device of this embodiment has an electro-optic material between a flat and optically sufficiently transparent first substrate 1 and a flat and transparent second substrate 2. A liquid crystal layer 3 is interposed therebetween, and the space between the liquid crystal layer 3 and the second substrate 2 serves as a discharge region 4. These substrates 1,
2 is formed of a non-conductive and optically transparent material here, but this is in consideration of a transmissive display device, and in the case of a direct view type or reflective display device, either It is sufficient if one of the substrates is transparent.

A transparent electrode 5 is formed on one main surface 1a of the first substrate 1, and a liquid crystal layer 3 made of 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), etc., and one main surface 1a of the first substrate 1
It is formed continuously over the entire surface of the electrode, making it a so-called solid electrode. Further, the liquid crystal layer 3 is sandwiched between the first substrate 1 and the first substrate 1 by a thin dielectric film 6 made of glass, mica, plastic, etc., and these first substrate 1, the liquid crystal layer 3, and the dielectric film 6 constitutes a so-called liquid crystal cell. This dielectric film 6 is a liquid crystal layer 3.
and functions as an insulating barrier layer for the discharge region 4,
Without the dielectric film 6, there is a risk that the liquid crystal material may flow into the discharge region 4 or that the liquid crystal material may be contaminated by gas within the discharge region 4. However, this may not be necessary if a solid or encapsulated electro-optic material is used instead of the liquid crystal material. Furthermore, since the dielectric film 6 is formed of a dielectric material, it also functions as a capacitor, and therefore, in order to ensure sufficient electrical coupling between the discharge region 4 and the liquid crystal layer 3, it is necessary to make it as thin as possible. It's better.

On the other hand, the second substrate 2 also has discharge electrodes arranged in XY
It is formed as a matrix electrode, and is arranged at a predetermined distance from the dielectric film 6 by sealing the periphery, and the space between the second substrate 2 and the dielectric film 6 is a discharge that generates discharge plasma. It is considered to be area 4. The above-mentioned discharge electrode is composed of a cathode electrode K formed directly on a second substrate 2 made of glass, and an anode electrode A laminated on this cathode electrode K with a dielectric layer 7 made of glass or the like interposed therebetween. has been done. The cathode electrode K and the anode electrode A are respectively cathode K1.
, K2, K3, K4, K5... and anodes A1, A2, A3, A4, A5..., which are arranged orthogonally to each other as shown in FIG.
It is considered to be an XY matrix electrode.

Further, the discharge region 4 is connected to the cathode K.
1, K2, K3, K4, K5... and anodes A1, A2, A3, A4, A5... separated by partition walls 8 formed by a printing method, each having an independent plasma chamber P. It is said that That is, the partition walls 8 are also formed vertically and horizontally like the XY matrix electrodes, and each plasma chamber P has the cathode K.
1, K2, K3, K4, K5... and the intersections of the anodes A1, A2, A3, A4, A5... are arranged. Therefore, each plasma chamber P has 1
This corresponds to pixels. In addition, each plasma chamber P
An ionizable gas is sealed in the ionizer, and the ionizable gas used may be helium, neon, argon, or a mixture thereof.

The partition wall 8 is formed by a printing method, for example, by laminating and printing glass paste multiple times by a screen printing method. here,
The partition wall 8 also plays the role of regulating the gap interval W of the discharge region 4, which can be controlled by adjusting the number of times of screen printing, the amount of glass paste during each printing, and the like. It is usually about 200 μm. In addition, the cathode electrode K and the anode electrode A are 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, since it can be formed on a flat surface, it can be easily formed, 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,
Image display is performed by the discharge plasma generated in each plasma chamber P functioning as a sampling switch. Hereinafter, to explain the display operation in the image display device of this embodiment, first, each cathode K1, K2, K3, K4
, K5... are turned on line by line in line sequence,
A voltage (for example, -200V) sufficient to start the discharge is applied. Other cathode lines are off (e.g. 0V
). On the other hand, each anode A1, A2, A3, A4, A
5... have turned-on cathodes K1, K2,
Analog voltages are simultaneously applied corresponding to K3, K4, K5, . . . This analog voltage is ±40V
The range is approximately pp, and each pixel is turned on or off. 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, and in the pixel corresponding to this plasma chamber P, the dielectric film 6 A voltage is applied between the transparent electrode 5 on the liquid crystal layer 3 side and the transparent electrode 5 via 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 (±40Vpp) is directly applied to the selected pixel in which both the cathode electrode K and the anode electrode A are turned on.
Charge is stored in the liquid crystal layer 3, which corresponds to a sampling capacitor, and is turned on.

The above is the display operation of the image display device of this embodiment. What is characteristic here is that local plasma discharge is turned on and off by the anode electrode A and cathode electrode K disposed on the discharge area side. When off, the analog voltage applied to each pixel is controlled. by this,
Crosstalk between display electrodes, which is unique to PALC and occurs due to the presence of the dielectric sheet, can be significantly reduced. Further, since the transparent electrode 5 on the liquid crystal layer 3 side can be a solid electrode, it is very advantageous in manufacturing. Furthermore, metal materials with high conductivity can be used for the electrodes on the discharge area side.
Problems such as wiring resistance when increasing the size can be avoided. Furthermore, since the dielectric layer 7 is formed on the cathode electrode K, this serves as a protective film to protect the cathode electrode K from ion sputtering, which is advantageous in terms of service 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 the material, shape, dimensions, etc. may be arbitrary. Furthermore, in the above embodiment, the partition walls are printed and formed corresponding to each intersection of the XY matrix electrodes, but they may be formed for each scanning line corresponding to the cathode electrodes, or depending on the case, It is not necessary to form partition walls at all.

[0017]

As is clear from the above description, in the present invention, the electrodes in the discharge region are XY matrix electrodes, and these XY matrix electrodes are used to turn on and off the discharge and to drive the electro-optic 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 has advantages in terms of life span, etc.

[Brief explanation of the drawing]

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

FIG. 2 is a schematic plan view of main parts schematically showing the arrangement of XY matrix electrodes and partition walls.

FIG. 3 is a partially cutaway schematic perspective view of an example of a conventional image display device.

[Explanation of symbols]

1...first substrate 2...Second board 3...Liquid crystal layer (electro-optic material layer) 4...discharge area 5...Transparent electrode K...Cathode electrode A...Anode electrode 8... Bulkhead

Claims (1)

[Claims] 1. A first substrate having a first electrode on one main surface, and a second substrate having a second electrode on one main surface, and the first substrate and the second substrate are connected to each other. A first electrode and a second electrode are arranged substantially parallel to each other so as to face each other, and an electro-optic material layer is interposed so as to be in contact with the first electrode of the first substrate. An image characterized in that an ionizable gas is sealed in the space between the two substrates to form a discharge region, and the second electrode is an XY matrix electrode consisting of an anode electrode and a cathode electrode orthogonal thereto. Display device.