JPH04265933A - Image display device - Google Patents

Abstract

PURPOSE:To increase the number of scanning lines and obtain a high-density pitch and a fine pitch by dividing a signal write electrode in scan units and forming a multiple matrix. CONSTITUTION:An electrode 3 is formed on one main surface of a 1st substrate 1 and a liquid crystal layer 3 made of nematic liquid crystal, etc., is arranged in contact with the electrode 3. In this case, the electrode 3 crosses grooves as a plasma channel at right angles and is divided into two at parts facing the respective grooves 4. Namely, the electrode 3 is the double matrix electrode consisting of pattern electrodes X1, X2 to Xm-1, Xm corresponding to the upper half of the respective plasma channels (groove 4) and pattern electrodes X'1, X'2 to X'm-1, X'm corresponding to the lower half of the respective plasma channels. Then the electrode 3 functions as a sampling capacitor for an analog voltage applied to the electrode 3 and discharge plasma generated in the respective plasma chambers P1, P2 to Pn functions as a sampling switch to display an image.

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 in 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]

By the way, in the above-mentioned image display device, the width of each scanning line is equal to the width of the plasma chamber 102.
It is determined by the width of the (groove 105), and from the physical characteristics of discharge, it is said that the limit is usually about 0.4 mm, and the minimum is about 0.25 mm. Therefore, this is one of the factors that hinders the development of finer pitches or higher density pitches in PALC. Therefore, the present invention was proposed to solve the problems of the conventional ones, and includes:
It is an object of the present invention to provide an image display device capable of achieving fine pitch and high density pitch of scanning lines.

[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 plurality of first electrodes substantially parallel to each other on one main surface; a plurality of second electrodes substantially perpendicular to the first electrode and substantially parallel to each other on the surface;
a second substrate having an electrode, the first substrate and the second substrate are arranged substantially parallel to each other such that the first electrode and the second electrode face each other; An electro-optic material layer is interposed so as to be in contact with the electrode, and an ionizable gas is sealed between the electro-optic material layer and the second substrate to form a discharge region, and the first electrode It is characterized by being divided into multiple matrixes.

[0008]

[Operation] In the image display device of the present invention, the first electrode, which is a signal writing electrode and is disposed perpendicular to each plasma channel (scanning line), is divided into a plurality of parts in each scanning unit and formed into a multiple matrix. There is. For example, the first electrode is divided into upper and lower halves in the plasma channel.
By creating a heavy matrix, the operation is equivalent to having two scanning lines for one plasma channel. Therefore, if the number of scanning lines is constant, the pitch of the plasma channels is halved, making processing easier.

[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 includes a flat first substrate 1 on which an electrode 3 is formed, a plurality of parallel grooves 4, and a discharge electrode in the groove 4. A liquid crystal layer 6, which is an electro-optical material layer, is interposed between the second substrate 2 on which the liquid crystal layer 5 is formed, and the space between the liquid crystal layer 6 and the second substrate 2, that is, the groove 4 serves as a discharge area. These substrates 1 and 2 are formed of a non-conductive and optically transparent material here, but this is done in consideration of a transmissive display device, and in the case of a direct view type or reflective display device. It suffices if either one of the substrates is transparent.

An electrode 3 is formed on one main surface of the first substrate 1, and a liquid crystal layer 6 made of nematic liquid crystal or the like is arranged in contact with the electrode 3. This liquid crystal layer 6 is sandwiched between a first substrate 1 and a dielectric film 7 made of glass, mica, plastic, etc., and these first substrate 1, liquid crystal layer 6, and dielectric film 7 provide
It has a so-called liquid crystal cell structure. Here, the electrode 3 is perpendicular to the grooves 4 serving as plasma channels, and has a pattern in which it is divided into upper and lower halves in the portion facing each groove 4. That is, the electrode 3 is
As shown in FIG. 2, pattern electrodes X1, X2,
...Xm-1, Xm and pattern electrodes X'1, X'2, X' corresponding to the lower half of each plasma channel
3...A double matrix electrode consisting of X'm-1 and X'm.

Further, the dielectric film 7 functions as an insulation barrier layer between the liquid crystal layer 6 and the discharge region 4, and without this dielectric film 7, the liquid crystal material would flow into the discharge region (groove 4). In addition, there is a risk that the liquid crystal material may be contaminated by the gas in the discharge region. However, if solid or encapsulated electro-optic materials are used instead of liquid crystal materials,
The dielectric film 7 may not be necessary. Note that since the dielectric film 7 is formed of a dielectric material, it also functions as a capacitor, thus ensuring sufficient electrical coupling between the discharge plasma generated within the groove 4 and the liquid crystal layer 6. However, in order to suppress the two-dimensional diffusion of charges, it is better to make it as thin as possible.

On the other hand, a discharge electrode 5 is also formed on the second substrate 2 as a strip-shaped electrode, and the space between the second substrate 2 and the dielectric film 7, that is, the space in each groove 4 is used for discharge. It is considered to be a discharge region that generates plasma. The discharge area is partitioned by partition walls 8 formed between the grooves 4, and is divided into independent plasma chambers P1, P2, P3...P.
n and is filled with an ionizable gas to form a plasma channel. As the ionizable gas, helium, neon, argon, or a mixed gas thereof is used. Further, the discharge electrodes 5 are formed in pairs in parallel to each other in the groove 4,
Discharge plasma is generated within the groove 4 by the discharge between these electrodes. Therefore, each plasma chamber P1, P2,
P3...Pn is the scanning unit.

The above is the general structure of the image display device of this embodiment. Electrodes for driving the liquid crystal layer 6 are formed on each of the substrates 1 and 2, respectively. Therefore, the configuration of these electrodes will be explained next.

First, a plurality of strip-shaped electrodes 3 having a predetermined width are formed on the main surface of the first substrate 1 facing the second substrate 2, and are used as signal writing electrodes. ing. These strip-shaped electrodes 3 are made of a transparent conductive material such as indium tin oxide (ITO), and are optically transparent. Further, the electrodes 3 are arranged parallel to each other, for example, perpendicular to the screen. As mentioned earlier, this electrode 3 is the pattern electrode X1 corresponding to the upper half of each plasma channel (groove 4).
, X2, X3...Xm-1, Xm and pattern electrodes X' corresponding to the lower half of each plasma channel.
1 ,X'2 ,X'3 ...X'm-1 ,X'm
It is said to be a double matrix electrode consisting of.

On the other hand, in the groove 4 of the second substrate 2,
A discharge electrode 5 is also formed. These discharge electrodes 5 are also parallel linear electrodes, but their arrangement direction is orthogonal to the electrodes 3 formed on the first substrate 1. That is, these discharge electrodes 5 are arranged horizontally on the screen. Further, these discharge electrodes 5 include anode electrodes A1, A2, A3...An-1, An and cathode electrodes K1, K2, K3...Kn-1.
, Kn, and a discharge electrode is constructed by pairing them, and each plasma chamber P1, P2, P3...
・One pair of each is arranged in Pn.

FIG. 3 schematically shows the arrangement of the electrodes 3 formed on the first substrate 1 and the discharge electrodes 5 formed on the second substrate. Here, among the discharge electrodes 5 on the second substrate 2, each cathode electrode K1, K2, K3...Kn
-1 and Kn are connected to a second signal applying means composed of a data strobe circuit 9 and an output amplifier 10, and a pulse voltage output from each output amplifier 10 is supplied as a data strobe signal. Moreover, each anode electrode A1, A2, A3...An-1, An
A common reference voltage (ground voltage) is applied to both. Therefore, the discharge electrode 5 formed on the second substrate 2
The connection structure is as shown in FIG. On the contrary,
A first signal applying means composed of a data driver circuit 11 and an output amplifier 12 is connected to the electrode 3 of the first substrate 1, and the analog voltage output from each output amplifier 12 is supplied as a liquid crystal drive signal. Ru. Here, the electrodes 3 are patterned electrodes X1, X2, X3...Xm-1, Xm corresponding to the upper half of each plasma channel,
Pattern electrodes X'1, X'2, X corresponding to the lower half
'3...X'm-1, X'm, each cathode electrode K1, K2,
As shown in FIG. 5, two electrode matrices are configured for K3...Kn-1 and Kn. In addition, in order to form an image over the entire display surface,
A scan control circuit 13 is provided connected to the data driver circuit 11 and data strobe circuit 9. The scan control circuit 13 adjusts the functions of the data driver circuit 11 and the data strobe circuit 9, and sequentially addresses all the pixel columns of the liquid crystal layer 6 from row to row.

In the image display device having the above configuration, the liquid crystal layer 6 functions as a sampling capacitor for the analog voltage applied to the electrode 3 formed on the first substrate 1, and the liquid crystal layer 6 functions as a sampling capacitor for the analog voltage applied to the electrode 3 formed on the first substrate 1, and P3...P
Image display is performed by the discharge plasma generated at n functioning as a sampling switch. A model for explaining this image display operation is shown in FIG. In FIG. 6, the liquid crystal layer 6 corresponding to each pixel can be regarded as a capacitor model 14. That is, the capacitor model 14 has pattern electrodes X1, X2, X3
...Xm-1, Xm and pattern electrode X'1
, X'2, X'3 . . .

Now, each pattern electrode X1, X2, .
It is assumed that an analog voltage is applied from the data driver circuit 11 to the pattern electrodes X'1, X'2, and so on. Here, if the data strobe signal (pulse voltage) is not applied to the cathode electrode K1 of the second substrate 2, that is, if it is in the off state, then the anode electrode A
1 and the cathode electrode K1 does not occur, and the gas in the plasma chamber P1 is not ionized. Therefore, the plasma switch S1 (pattern electrodes X1, X2, . . . and pattern electrodes X'1,
X'2... and the anode electrode A1) are also turned off, and these pattern electrodes X1, X2
,... and pattern electrodes X'1, X'2...
No matter what analog voltage is applied to the capacitor model 14, the potential difference across each capacitor model 14 remains unchanged.

On the other hand, the cathode electrode K2 of the second substrate 2
When a data strobe signal is applied to P2, that is, it is in the ON state, the gas is ionized by the discharge between the anode electrode A2 and the cathode electrode K2, and an ionized region (discharge plasma) is generated in the plasma chamber P2. . Then, the pattern electrodes X1, X2, . . . and the pattern electrodes X'1, X'2, . Sometimes the state is equivalent to that of plasma switch S2 being turned on. As a result, the capacitor model 14 of the column in which the cathode electrode K2 is strobed includes each pattern electrode X1, X2, .
The analog voltages supplied to X'2... are stored. Even after the strobe to the cathode electrode K2 ends and the discharge plasma disappears, this analog voltage is stored in each capacitor model 14 until the next strobe is performed (at least during the field period of the image). The pattern electrode
, X2, ... and pattern electrodes X'1, X'2
It is not affected by subsequent changes in the analog voltage applied to...

[0020] Therefore, the cathode electrodes K1, K2
, K3...Kn-1, Kn are sequentially addressed and a data strobe signal is applied for a time equivalent to two scanning lines,
While generating discharge plasma sequentially in the plasma chambers P1, P2, P3...Pn, each pattern electrode
1, X2,... and pattern electrodes X'1, X'
By applying a liquid crystal drive signal as an analog voltage to 2... in synchronization with this, two plasma channels (each plasma chamber P1, P2, P3...Pn) can be
The equivalent operation is that there are two scan lines.

Although specific embodiments to which the present invention is applied have been described above, the present invention is not limited to these embodiments. For example, in this example, a double matrix is used, but the electrode configuration may be a triple matrix or more. Regarding the structure, each plasma chamber in this example is formed by a groove, but it may also be partitioned by a partition wall formed by a printing method. Alternatively, an open cell structure without any partition walls may be used.

[0022]

[Effects of the Invention] As is clear from the above explanation, in the present invention, the signal writing electrode is divided into a plurality of parts in each scanning unit and is formed into a multiplexed matrix, which greatly increases the number of scanning lines and achieves high density. It can be made into pitch or fine pitch. Conversely, the number of plasma channels, which is regulated in principle by plasma characteristics, can be significantly reduced, and can be halved, for example, by forming a double matrix. Therefore, the number of plasma drive circuits that require high voltage can be reduced by half, and the plasma channel can be easily processed, which is very advantageous in terms of circuit configuration and manufacturing.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of essential parts of an embodiment of an image display device to which the present invention is applied.

FIG. 2 is a schematic plan view of a main part schematically showing an electrode pattern of a signal writing electrode.

FIG. 3 is a schematic diagram showing an electrode configuration for driving a liquid crystal layer.

FIG. 4 is a schematic diagram showing the arrangement and connection state of discharge electrodes.

FIG. 5 is an equivalent circuit diagram of a double matrix drive circuit.

FIG. 6 is an equivalent circuit diagram for explaining an image display operation.

FIG. 7 is a schematic cross-sectional view showing an example of a conventional image display device.

[Explanation of symbols]

1...first board 2...Second board 3...electrode 5...Electrode for discharge 6...Liquid crystal layer (electro-optic material layer)

Claims (1)

[Claims] Claim 1: A plurality of first surfaces substantially parallel to each other on one principal surface.
A first substrate having an electrode, and a second substrate having a plurality of second electrodes on one principal surface that are substantially orthogonal to the first electrode and substantially parallel to each other. substrates are arranged substantially parallel to each other so that a first electrode and a second electrode 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 An image display device characterized in that an ionizable gas is sealed between the layer and the second substrate to form a discharge region, and the first electrode is divided into a plurality of parts in each scanning unit to form a multiple matrix.