JPH11143393A - Method of manufacturing image display device - Google Patents

Abstract

(57) [Problem] To manufacture an image display device (plasma address display device) in which a plasma cell and an electro-optical display cell are stacked with a dielectric thin plate interposed therebetween, and to manufacture a dielectric material for sealing the plasma cell. Prevents contamination of sheets. SOLUTION: When firing a sealing material between a dielectric thin plate and a first substrate of a plasma cell in a firing furnace, a cover glass is overlaid on the dielectric thin plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an image display device for selecting an image by driving an electro-optic material layer using plasma.

[0002]

2. Description of the Related Art In general, as means for increasing the resolution and contrast of a display, for example, there is a method of providing an active element such as a transistor for each display pixel and driving the same, that is, a so-called active matrix address method. . However, in this case, since it is necessary to provide a large number of semiconductor elements such as thin film transistors,
In particular, when the area of the display is increased, there is a concern about the yield problem, and there is a problem that the cost is inevitably increased.

Therefore, as a means for solving this problem,
A method has been proposed in which discharge plasma is used as an active element instead of a semiconductor element such as a MOS transistor or a thin film transistor.

Hereinafter, an example of an image display device (hereinafter, referred to as a plasma address display device) that drives a liquid crystal using the discharge plasma will be briefly described.

[0005] This image display device comprises a liquid crystal layer, which is an electrochemical material layer, and a plasma cell in which plasma is discharged, which are disposed adjacent to each other via a dielectric thin plate such as a thin glass plate.

The plasma cell is constructed by arranging the dielectric thin plates at predetermined intervals on a glass substrate on which a plurality of discharge electrodes substantially parallel to each other are formed, and sealing the periphery with a frit seal. . This plasma cell is
The space between the first substrate made of glass and the dielectric thin plate is
For example, partitions are formed by forming partition walls, and each partitioned space is a discharge region.

On the other hand, a liquid crystal layer is disposed between the dielectric thin plate and a second substrate disposed on the dielectric thin plate at a predetermined interval. A transparent electrode substantially orthogonal to the discharge electrode is formed on the second substrate, and each intersection region between the electrode and each of the plasma electrodes corresponds to each pixel.

In such a plasma addressed display device, the discharge region in which plasma discharge is performed is sequentially switched and scanned, and a signal voltage is applied to the transparent electrode on the liquid crystal layer side so that the signal voltage is held in each pixel. ,
The liquid crystal layer is driven.

By the way, such a plasma addressed display device has been manufactured as follows.

That is, a dielectric thin plate is laminated on a first substrate on which a discharge electrode and a partition wall are formed via a sealing material made of low melting point glass or the like, and is transferred to a firing furnace in this state and heated. The sealing material is fired. Thereby, the space between the first substrate and the thin dielectric plate is hermetically sealed.
Then, a plasma cell is formed by filling an ionizable gas into each discharge region partitioned by a partition wall between the first substrate and the dielectric thin plate.

Subsequently, for example, a polyamic acid is applied on the dielectric thin plate and baked to form an alignment film made of polyimide. On the dielectric thin plate, a data electrode, a color filter, and an alignment film formed with an alignment film are formed. The two substrates are arranged via a spacer. Then, a liquid crystal layer is formed by injecting, for example, twisted nematic liquid crystal between the dielectric thin plate and the second substrate.

[0012]

However, in such a method of manufacturing a plasma addressed display device, in the step of firing the sealing material of the plasma cell, the gas generated during firing and dust in the firing furnace are exposed to the dielectric material. There is a problem that it adheres to the thin plate surface and burns.

When dust or the like is burned on the surface of the dielectric thin plate, poor orientation occurs in the liquid crystal layer laminated thereon, and a displayed image has poor image quality such as white flaws.

Further, if burn-in such as dust adheres to the surface of the dielectric thin plate, a process of forming an alignment film on the dielectric thin plate and a process of superimposing the second substrate on the dielectric thin film are required. Cracks and cracks enter the dielectric thin plate, causing troubles such as breaking the vacuum in the plasma cell.

Accordingly, the present invention has been proposed in view of such conventional circumstances, and provides a method of manufacturing an image display device capable of sealing a plasma cell without adhering dust or the like to a dielectric thin plate. The purpose is to do.

[0016]

In order to achieve the above-mentioned object, a method of manufacturing an image display device according to the present invention is provided on a first substrate on which a plurality of substantially parallel discharge electrodes and a plurality of partition walls are formed. A step of bonding a plurality of dielectric thin plates to each other, bonding the dielectric thin plate on the first substrate side to the first substrate with a sealing material disposed around, and firing the sealing material by heat treatment; The dielectric thin plate superimposed on the dielectric thin plate adhered to the first substrate is removed, and an electrode substantially orthogonal to the discharge electrode is formed on the facing surface of the dielectric thin plate adhered to the first substrate. And a step of injecting an electrochemical material into a gap between the dielectric thin plate and the second substrate, and a step of superimposing the formed second substrates with a predetermined gap therebetween.

In this manufacturing method, a plurality of thin dielectric plates are stacked on the first substrate via a sealing material, and the sealing material is fired in this state. Is protected by a dielectric thin plate superposed thereon to prevent gas, dust and the like in the firing atmosphere from adhering.

Therefore, since the surface of the dielectric thin plate on the first substrate side is in a clean state, in the step of forming the electrochemical material layer, the dielectric thin plate on the first substrate side has good orientation. A liquid crystal layer is formed. In addition, cracks and cracks are prevented from being formed in the dielectric thin plate during the step of disposing the second substrate and the like, and the vacuum state of the plasma cell is reliably maintained.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

First, the plasma addressed display device manufactured in this embodiment will be described.

As shown in FIGS. 1 and 2, this plasma addressed display device has a so-called flat structure in which an electro-optical display cell 1, a plasma cell 2, and a dielectric thin plate 3 interposed therebetween are laminated. It has a panel structure.

The dielectric thin plate 3 is made of a material having translucency,
For example, a thin glass plate having a thickness of 30 to 50 μm is used, and functions as a capacitor by itself. Therefore, in order to sufficiently secure the electrical coupling between the electro-optical display cell 1 and the plasma cell 2 and to suppress the two-dimensional spread of the electric charge, it is better that the thickness of the dielectric thin plate 3 is as thin as possible. The higher the permittivity, the better.

The plasma cell 2 includes the dielectric thin plate 3
And a glass substrate (first substrate) 4 arranged below the glass substrate.

A rib 4a is formed on the outer peripheral edge of the first substrate 4 on the side facing the thin dielectric plate 3, and the rib 4a
Anode electrodes 5 extending in the column direction in a region surrounded by
A and the cathode electrode 5K are alternately arranged in parallel while maintaining a predetermined interval, and constitute a discharge electrode group.

A partition 6 having a predetermined width is formed at the center of the upper surface of each anode electrode 5A so as to extend along the electrode. The top of each partition 6 is in contact with the lower surface of the dielectric thin plate 3, and the gap between the first substrate 4 and the dielectric thin plate 3 is kept substantially constant.

Further, the dielectric thin plate 3 is hermetically bonded to the ribs 4a of the first substrate 4 by a sealing material 15 using low melting point glass or the like, so that the plasma cell 2 serves as a closed space. It is configured. An ionizable gas such as helium, neon, argon, or a mixed gas thereof is sealed in the closed space.

This closed space is separated by each partition 6, and a plurality of separated spaces are used as discharge channels 7.

On the other hand, the electro-optical display cell 1 is formed by bonding a glass substrate (second substrate) 9 on the dielectric thin plate 3 while maintaining a predetermined gap by a liquid crystal sealing material 8. Is done.

Then, the dielectric thin plate 3 and the second substrate 9
The alignment film 10 for adjusting the alignment of the liquid crystal
Liquid crystal layer 11 sandwiched between a and 10b is formed. In addition, as the electro-optic material, a material other than the liquid crystal can be used.

Here, the size of the gap between the second substrate 9 and the dielectric thin plate 3 is, for example, 4 to 10 μm, and is kept substantially uniform over the entire display surface.

A plurality of data lines extending in a direction orthogonal to the discharge electrodes 5 (anode electrode 5A and cathode electrode 5K), that is, in a row direction, are provided on the surface of the second substrate 9 facing the dielectric thin plate 3. The electrodes 12 are arranged in parallel in the column direction while maintaining a predetermined interval. The data electrode 12 is made of a transparent conductive material such as indium tin oxide (ITO). On the data electrode 12, a color filter 13 and an alignment film 10b are stacked.

In the above-described plasma addressed display device, a plurality of discharge channels 7 separated by each partition 6 are formed in parallel in the row direction in the gap between the first substrate 4 and the dielectric thin plate 3. The discharge channel 7 is connected to the data electrode 12
The intersection area between the discharge channel 7 and the data electrode 12 corresponds to each pixel 14. By sequentially switching the discharge channel 7 in which the plasma discharge is performed and applying a signal voltage to the data electrode 12 on the liquid crystal layer 11 side in synchronism with the operation, the signal voltage is applied to each pixel 1.
4 and the liquid crystal layer 11 is driven.

The above is the configuration of the plasma addressed display device. In a manufacturing method to which the present invention is applied, such a plasma addressed display device is manufactured as follows.

First, as shown in FIG.
A first substrate 21 on which 1a is formed is prepared, and discharge electrodes 22A and 22K and a partition 23 are formed in a region of the first substrate 21 surrounded by a rib 21a as shown in FIG.

The discharge electrodes 22A and 22K are formed by, for example, printing a conductive paste containing Ni powder or the like by screen printing so that a plurality of strip-shaped paste layers are formed at equal intervals, and then drying and firing. I do.

The partition walls 23 are formed by printing a lead glass paste at every other discharge electrode at the center of the discharge electrode by, for example, a screen printing method, followed by drying and firing. The lead glass paste is laminated and printed a plurality of times, for example, 10 to 15 times so that the partition walls are formed at a predetermined height.

When forming the discharge electrodes 22A and 22K and the partition walls 23 by the screen printing method in this manner, the conductive paste layer and the lead glass paste layer are not fired in separate steps, but the conductive paste layer is fired. Before the formation, a lead glass paste layer may be formed by printing, and thereafter, both paste layers may be baked collectively.

Next, a sealing material made of low-melting glass is applied to the top of the rib 21a of the first substrate 21, and a thin dielectric plate is laminated to seal the plasma cell. The plasma cell is sealed in the steps as described above.

That is, as shown in FIG.
4, a thin dielectric plate (hereinafter referred to as a cover glass) 25;
Are laminated in close contact to form a laminated glass. In addition, when the dielectric thin plate 24 and the cover glass 25 are overlapped, van der Waals force acts on both opposing surfaces, and both are strongly adhered.

Here, it is desirable that the thin dielectric plate 24 be thin and have a high dielectric constant in order to efficiently apply an external voltage to the liquid crystal layer. Further, in order to enhance the adhesion to the cover glass, the dielectric thin plate is preferably flat. From such a point, it is made of borosilicate glass having a low concentration of an alkali component, and has a thickness of 30 to 50 μm,
It is desirable to use microsheet glass having a flatness (center line average roughness Ra) of 5 to 10 μm.

On the other hand, the cover glass 25 is also made of the dielectric thin plate 2.
It is desirable to use a material having good flatness in order to make it tightly adhere to 4, and it is preferable to use a material which is the same material as the dielectric thin plate 24, has the same flatness, and is thicker than the dielectric thin plate 28.

Here, the dielectric thin plate 24 and the cover glass 2
The combination of 5 has a total thickness of 200 to 300 μm when both are superposed to prevent cracking and chipping during work.
It is preferred to choose m. Therefore, for example, when the thickness of the dielectric thin plate 24 is 50 μm, the cover glass 25 having a thickness of about 200 μm is used. When the thickness of the dielectric thin plate 24 is smaller than 50 μm,
For example, when the thickness is 30 μm, the thickness is 200 to 250.
Use a cover glass 25 with a thickness of about
Two or three μm cover glasses 25 may be used in layers to reinforce.

Then, as shown in FIG. 6, the laminated glass comprising the dielectric thin plate 24 and the cover glass 25 is slightly larger in area than the dielectric thin plate 24 and the cover glass 25, and a rib is formed on the outer peripheral edge. The holding glass 26 having 26a is accommodated inside the rib 26a.
At this time, the dielectric thin plate 24 is positioned above the cover glass 25. Next, as shown in FIG. 7, the top of the rib 21 a on which the sealing material 27 of the first substrate 21 is applied is brought into contact with the dielectric thin plate 24. And FIG.
As shown in FIG. 1, these first substrate 21, dielectric thin plate 24,
The cover glass 25 and the holding glass 26 are attached to the first substrate 21.
It is fixed using a jig 28 sandwiched from the side and the holding glass 26 side, and is heated by a firing furnace in a state where the stacking order is reversed. When heated, the ribs 21a of the first substrate 21
The sealing material 27 between the first thin film and the dielectric thin plate 24 is sintered, and the space between the first substrate 21 and the thin dielectric plate 24 is hermetically sealed.

When the firing is performed in this manner, since the cover glass 25 is in close contact with the dielectric thin plate 24, gas, dust, and the like in the firing atmosphere are prevented from adhering to the surface of the dielectric thin plate 24, The surface of the dielectric thin plate 24 is kept clean.

Subsequently, the space between the sealed first substrate 21 and the thin dielectric plate 24 is evacuated and filled with an ionizable gas to form a plasma cell. Then, as shown in FIG. 9, the jig 28 and the holding glass 26 are removed, and the cover glass 25 is further attached to the dielectric thin plate 24.
Peel from The peeling of the cover glass 25 is performed, for example, by bonding an adhesive tape to the cover glass 25 and pulling the adhesive tape in a direction in which the cover glass 25 is peeled.

Thereafter, an electro-optical display cell is formed on the plasma cell. The formation of the electro-optical display cell may be in accordance with a normal manufacturing process of an image display device.

That is, as shown in FIG. 10, a TiO ₂ solution is applied onto the dielectric thin plate 24, prebaked, and then baked, so that TiO ₂
A film 29 is formed. Next, on this TiO ₂ film 29,
For example, a polyamic acid solution is applied, prebaked, baked, and rubbed to form an alignment film 30 made of polyimide. The rubbing treatment is a process of arranging polymer chains by rubbing a polyimide with a cloth. Then, a second substrate on which a data electrode, a color filter, and a second alignment film are formed is disposed with a predetermined gap therebetween through a liquid crystal encapsulant, and the first alignment film and the second alignment film are formed on the second substrate. The liquid crystal display device shown in FIGS. 1 and 2 is completed by injecting and sealing a liquid crystal such as a twisted nematic liquid crystal between the two alignment films.

At this time, in this manufacturing method, the dielectric thin plate 2
4 Since the surface is kept in a clean state, a liquid crystal layer having good orientation is formed, and cracks and cracks are formed in the dielectric thin plate 24 during the step of arranging the second substrate and the rubbing treatment of the orientation film. Thus, the vacuum state of the plasma cell is reliably maintained. Therefore, an image display device with good image quality is manufactured with a high yield.

Since the dielectric thin plate 24 is hardly cracked or cracked, a thin glass plate having a relatively small thickness can be used as the dielectric thin plate 24. When the thickness of the dielectric thin plate 24 is small, the electrical coupling between the electro-optical display cell and the plasma cell becomes strong, so that the external voltage applied to the data electrodes can be reduced, and the potential difference between the data electrodes decreases.
As a result, the liquid crystal domain is reduced, the alignment of the liquid crystal is improved, and the contrast and the like are improved.

The above are the basic steps of the manufacturing method of the present invention, and various changes may be made without departing from the present invention.

[0051] For example, in order to prevent dust adhesion of the baking step of the TiO ₂ film 29 and an alignment film 30, after prebaking of the TiO ₂ film 29, as shown in FIG. 11, stood up from the main surface to the outer peripheral edge portion The baking may be performed in a state where a thick cover glass 31 having two steps 31 a is covered and a clean space is formed between the surface of the TiO ₂ film 29 and the thick cover glass 31. The same applies to the case of the alignment film 30. As shown in FIG. 12, a clean space is provided between the alignment film 30 and the thick cover glass 31 by covering the thick cover glass 31 having two steps. Is formed, and firing is performed in this state. Further, such a thick plate cover glass 31 may be used in the firing process of the alignment film on the second substrate.

Further, dust on the surface can be removed by performing a static elimination air blow before applying the TiO ₂ solution or applying the polyamic acid solution, or by using a static elimination device such as an ultraviolet blower after rubbing the alignment film. Alternatively, cleaning with isopropyl alcohol may be performed.

By performing these washing operations, defective alignment of liquid crystal due to dust adhesion and cracks and cracks in the dielectric thin plate are further prevented, and the image quality and yield of the plasma addressed display device are further improved. .

In this embodiment, the partitions are arranged on the anode electrode. However, they may be arranged directly on the first substrate, or may be arranged on both the anode electrode and the cathode electrode. Is also good.

The partition may be formed by processing a thin glass into a predetermined partition pattern by a sand blast method, a scribe-break method, a grinding method, a laser cutting method or the like, instead of the screen printing method. .

[0056]

As is clear from the above description, in the method of manufacturing an image display device of the present invention, a plurality of dielectric thin plates are stacked on a first substrate via a sealing material. Since the sealing material is fired, it is possible to prevent dust and the like from adhering to the dielectric thin plate on the first substrate side in this firing step. Therefore, the surface of the dielectric thin plate on the first substrate side is kept in a clean state.
An electrochemical material layer having good orientation can be formed on the surface of the dielectric thin plate on the side of the substrate, and cracks and cracks are prevented from being formed in the dielectric thin plate during the step of disposing the second substrate and the like. . For this reason, it is possible to manufacture an image display device with good image quality at a high yield.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an image display device manufactured by a manufacturing method of the present invention, with a part cut away.

FIG. 2 is a schematic sectional view showing an image display device manufactured by the manufacturing method of the present invention.

FIG. 3 is a schematic cross-sectional view showing one example of a manufacturing method of the present invention in the order of steps and showing a first substrate used for manufacturing an image display device.

FIG. 4 is a schematic cross-sectional view showing a step of forming a discharge electrode and a partition.

FIG. 5 is a schematic sectional view showing a step of laminating a dielectric thin plate and a cover glass.

FIG. 6 is a schematic cross-sectional view illustrating a process of housing the laminated glass in the holding glass.

FIG. 7 is a schematic cross-sectional view showing a step of laminating a first substrate and a laminated glass.

FIG. 8 is a schematic sectional view showing a firing step of the sealing material.

FIG. 9 is a schematic sectional view showing a step of removing a cover glass superimposed on a dielectric thin plate on a first substrate side.

FIG. 10 is a schematic cross-sectional view showing a step of forming a TiO ₂ film and an alignment film.

FIG. 11 is a schematic sectional view showing a firing step of a TiO ₂ film.

FIG. 12 is a schematic sectional view showing a firing step of an alignment film.

[Explanation of symbols]

1. Electro-optical display cell, 2. Plasma cell, 3, 24
Dielectric thin plate, 4, 21 first substrate, 5A, 22A anode electrode, 5K, 22K cathode electrode, 6 partition, 7
Discharge channel, 8 liquid crystal sealing material, 9 second substrate, 1
0a, 10b, 30 alignment film, 11 liquid crystal layer, 12 data electrode

Claims (2)

[Claims] 1. A plurality of dielectric thin plates are stacked on a first substrate on which a plurality of substantially parallel discharge electrodes and a plurality of partition walls are formed, and a dielectric thin plate on the first substrate side is disposed around the first thin dielectric plate. Adhering to the first substrate with the encapsulant, baking the encapsulant by heat treatment, removing the dielectric thin plate superimposed on the dielectric thin plate adhered to the first substrate, Superposing a second substrate having an electrode substantially orthogonal to the discharge electrode on the opposing surface on a dielectric thin plate bonded to the first substrate with a predetermined gap therebetween; And injecting and sealing an electrochemical material into a gap between the substrates. 2. After removing the dielectric thin plate superimposed on the dielectric thin plate adhered to the first substrate, a coating film containing an alignment material is formed, and the coating film is baked to be oriented. 2. The method according to claim 1, further comprising a step of forming a film, wherein a cover glass is placed on the coating when firing the coating.