JPH07176267A - Manufacture of plasma address liquid crystal display device - Google Patents

Abstract

PURPOSE:To stably perform a process of polishing a partition formed in a plasma cell of a plasma address liquid crystal display device. CONSTITUTION:A plasma address liquid crystal display device, in which a plasma call and a liquid crystal cell are superposed on each other through an intermediate sheet, is manufactured as follows. First in a substrate 2 previously formed a plasma electrode 1, stripe-shaped partitions 3 are formed to be printed. Next, a part between the stripe-shaped partitions 3 is changed with a temporary reinforcing material 4, to bury the periphery of the individual partition. Successively in a buried condition, a top part of each partition 3 is polished and flattened. Thereafter, the temporary reinforcing material 4 is removed to expose a plasma electrode 1. Finally coming into contact with the flattened top part of each partition 3, the intermediate sheet is connected to assemble the plasma cell.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma addressed liquid crystal display device in which a plasma cell and a liquid crystal cell are superposed on each other via an intermediate sheet. More specifically, the present invention relates to a plasma cell manufacturing method using a screen printing method.

[0002]

2. Description of the Related Art The structure of a conventional plasma addressed liquid crystal display device will be briefly described with reference to FIG. A plasma addressed liquid crystal display device is disclosed in, for example, Japanese Patent Laid-Open No. 265931/1992. As shown, the plasma addressed liquid crystal display device includes a liquid crystal cell 101 and a plasma cell 102.
And an intermediate sheet 103 interposed between the two. The intermediate sheet 103 needs to be as thin as possible in order to drive the liquid crystal cell 101, and for example, an ultrathin plate glass having a thickness of about 50 μm is used. Liquid crystal cell 101
Is formed by using the upper glass substrate 104, and the signal electrodes D are formed in stripes on the inner main surface thereof. The substrate 104 is adhered to the intermediate sheet 103 via a spacer 105 with a predetermined gap. A liquid crystal layer 106 is filled in the gap. This gap size is usually 5
It is about μm and must be kept uniform over the entire display surface.

On the other hand, the plasma cell 102 is constructed using a lower glass substrate 107. A plurality of plasma electrodes 108 are patterned in stripes on the main surface of the glass substrate 107. The glass substrate 107 is bonded to the intermediate sheet 103 via a frit seal material 109. An ionizable gas is enclosed in the space sealed by the frit seal material 109. A partition 110 is formed along each plasma electrode 108 by a screen printing method. The plasma cell 102 is divided into stripes by the partition wall 110 and constitutes a discharge channel. This screen printing method is a simple technique and can form a fine pattern, and the productivity and workability are significantly improved.

[0004]

By the way, the partition wall 110
Although it is formed by screen printing, it functions as a gap spacer of the plasma cell 102, so that a considerable thickness is required. However, the heights of the partition walls 110 vary, and irregularities such as screen mesh residue occur at the tops of the individual partition walls. Therefore, in the state where the top of the partition wall 110 and the intermediate sheet 103 made of ultrathin sheet glass are in contact with each other, the surface of the intermediate sheet is undulated and the flatness cannot be maintained. As a result, the liquid crystal layer 106 on the liquid crystal cell 101 side.
The thickness cannot be controlled uniformly and the display quality is significantly impaired. Further, the gap distance between the lower glass substrate 107 and the intermediate sheet 103 also varies, and uniform plasma discharge cannot be obtained.

Therefore, a measure is taken in which the partition wall 110 is printed and fired thickly in advance and then subjected to a polishing treatment to be flattened. However, the width of the partition 110 is usually set to about 100 μm, and the height is 100 μm.
It is set to ˜300 μm. Since the height dimension is larger than the width dimension, the mechanical strength is weak, and particularly the partition wall end is fragile. For this reason, there is a problem that when the polishing treatment for flattening the top portion is performed after printing and firing, the partition wall is damaged or collapsed due to mechanical stress.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, it is an object of the present invention to provide a method of manufacturing a plasma addressed liquid crystal display device capable of performing a stable polishing process on the tops of partition walls. The following measures have been taken in order to achieve this object. That is, a plasma addressed liquid crystal display device in which a plasma cell and a liquid crystal cell are superposed on each other via an intermediate sheet is manufactured by the following steps. First, a partition wall forming step of printing and forming stripe-shaped partition walls on a substrate on which plasma electrodes are formed in advance is performed. Next, a temporary reinforcing step is performed in which the temporary reinforcing material is filled between the stripe-shaped partition walls to embed the periphery of each partition wall. Then, a polishing step of polishing and flattening the tops of the partition walls in the embedded state is performed. Further, a removing step of removing the temporary reinforcing material and exposing the plasma electrode is performed. Finally, a joining step is performed in which the flattened tops of the respective partition walls are brought into contact with each other to join the intermediate sheets to assemble a plasma cell. After this, the liquid crystal cell is assembled by stacking it on the plasma cell to complete the plasma addressed liquid crystal display device.

[0007] Specifically, in the temporary reinforcing step, the ultraviolet curable resin is supplied to the substrate and then cured to form a temporary reinforcing material. Further, in the removing step, the temporary reinforcing material made of the ultraviolet curable resin is dissolved in agitated warm water. Preferably, in the temporary reinforcing step, the temporary reinforcing material may be filled at a height level that is not less than half the height of the printed partition wall and not more than the polishing amount of the partition top. In some cases, instead of the water-soluble UV-curable resin, a thermoplastic resin such as water-soluble polyethylene glycol can be used as the temporary reinforcing material.

[0008]

According to the present invention, the barrier ribs are screen-printed in stripes and further fired, and then the temporary reinforcing material is filled prior to the polishing treatment so that the periphery of the barrier ribs is embedded. As a result, the partition walls having relatively low mechanical strength are reinforced, and it is possible to sufficiently withstand the mechanical stress applied during the polishing process. This makes it possible to produce a high-quality plasma cell with high yield. After the polishing process, the used temporary reinforcing material is removed and the plasma electrode is exposed. An ultraviolet curable resin is suitable as the temporary reinforcing material. Unlike thermosetting resins, there is no risk of damaging the partition walls because they are not substantially deformed during the curing process. Furthermore, if a water-soluble UV-curable resin is used, it can be easily dissolved and removed in warm water with stirring, so that it does not adversely affect the underlying plasma electrode.
In addition, water-soluble polyethylene glycol is also suitable as a temporary reinforcing material, and is easier to handle than ultraviolet curable resins.

[0009]

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 process diagram showing a main part of a method of manufacturing a plasma addressed liquid crystal display device according to the present invention.
First, the partition wall forming step shown in (A) is performed. That is,
Stripe-shaped partition walls 3 are formed by printing on the substrate 2 on which the plasma electrode 1 is formed in advance. Overprinting is performed to obtain the desired height dimension. However, the heights of the individual partition walls 3 include a certain amount of variation, and the tops of the partition walls 3 have irregularities such as traces of the screen mesh used for printing. Next, the temporary reinforcing step shown in (B) is performed. Here, the temporary reinforcing member 4 is provided between the stripe-shaped partition walls.
To fill in the periphery of each partition 3. Preferably, the filling amount of the temporary reinforcing material 4 is set to a height level that is not less than half the height of the printed partition walls 3 and not more than the polishing amount of the tops of the partition walls 3. If the temporary reinforcing material 4 is less than half the height of the partition wall 3, desired mechanical strength cannot be obtained, and the partition wall 3 may collapse due to polishing in a subsequent process. Further, if the temporary reinforcing material 4 is filled up to a height level equal to or higher than the polishing amount, the polishing process in the subsequent process may be adversely affected. If the surface height of the temporary reinforcing member 4 is set in advance according to the polishing amount, the end point of the polishing process can be detected almost automatically. In this example, an ultraviolet curable resin is used as the temporary reinforcing material 4. In this case, since the heat treatment is not required, the volume change of the filled temporary reinforcing material does not occur, and unnecessary mechanical stress is not applied to the partition wall 3. Next, the polishing step shown in (C) is performed,
The top of each partition wall 3 is polished and flattened. At the same time, the height of each partition 3 can be made uniform. Finally, the removal step shown in (D) is performed. That is, the temporary reinforcing material is removed to expose the underlying plasma electrode 1. In this case, if a water-soluble UV-curable resin is used as a temporary reinforcing material, the removal can be performed very easily. For example, the UV curable resin is dissolved by being immersed in warm water with stirring and can be peeled off very easily. If this method is adopted, it is not necessary to consider the chemical resistance of the plasma electrode or the partition. After this, a joining step is carried out in which the plasma sheet is assembled by contacting the flattened top of the partition wall and joining the intermediate sheet. Further, a liquid crystal cell is assembled on the plasma cell to complete a plasma addressed liquid crystal display device.

FIG. 2 is a schematic cross-sectional view showing a completed product state of the plasma addressed liquid crystal display device manufactured as described above. In the completed state as shown in the figure, the plasma addressed liquid crystal display device has a liquid crystal cell 11 and a plasma cell 12.
And an intermediate sheet 13 interposed between the two are a flat panel. The intermediate sheet 13 needs to be as thin as possible in order to drive the liquid crystal cell, and for example, an extremely thin glass plate having a plate thickness of about 50 μm is used. Liquid crystal cell 1
Reference numeral 1 denotes a glass substrate 14, and a plurality of signal electrodes D made of a transparent conductive film are formed on the inner main surface of the glass substrate 14 in parallel to each other in the column direction. Glass substrate 14
Is the intermediate sheet 1 through a predetermined gap using the spacer 15.
It is glued to 3. A liquid crystal layer 16 is filled in the gap. This gap size is usually about 5 μm and must be kept uniform over the entire display surface. For this reason, although not shown, usually, spacer particles having a predetermined particle diameter are scattered in the gap. Further, since the intermediate sheet 13 is supported by the partition walls 3 whose surface is flattened by polishing and whose heights are uniform, the surface state thereof is extremely flat. Thereby, the gap size of the liquid crystal cell 11 can be controlled within an error of about ± 0.1 μm.

On the other hand, the plasma cell 12 is constructed by using the above-mentioned substrate 2. A plasma electrode 1 is formed on the inner main surface of the substrate 2. The plasma electrode 1 alternately functions as an anode A and a cathode K to generate plasma discharge. Since the temporary reinforcing material is completely removed from the surface of each plasma electrode 1, there is no fear of adversely affecting the discharge. A partition wall 3 is formed along the plasma electrode 1. As described above, the tops of the partition walls 3 are flattened by the polishing process, and contact the intermediate sheet 13 to control the gap size between the plasma cell 12 and the liquid crystal cell 11 to be constant. A frit seal material 17 made of low-melting glass or the like is provided outside the partition wall 3 along the peripheral portion of the substrate 2, and joins the intermediate sheet 13 and the substrate 2 together. A hermetically sealed discharge channel P is formed between the two.
An ionizable gas is enclosed inside the discharge channel P. The gas species can be selected from, for example, helium, neon, argon, xenon or a mixed gas thereof. A pair of adjacent plasma electrodes 1 or anodes A
When a predetermined voltage is applied between the cathode and the cathode K, the enclosed gas is selectively ionized to form the localized discharge region S of the ionized gas. The discharge area S is substantially limited by the barrier ribs 3 and serves as a row scanning unit. Each pixel is located at the intersection of the discharge channel P and the signal electrode D. In this example, the partition wall 3 is provided so as to be aligned with the plasma electrode 1, but the present invention is not limited to this. For example, a pair of plasma electrodes functioning as an anode A and a cathode K may be provided between a pair of partition walls adjacent to each other. In addition, in some cases, the plasma electrode 1 and the partition walls 3 may be provided in directions orthogonal to each other to form a so-called open cell structure.

Next, a specific example of a method of manufacturing a plasma addressed liquid crystal display device according to the present invention will be described in detail with reference to the flowchart of FIG. 3 and with reference to FIGS. First, in step S1, printing of plasma electrodes is performed. For example, nickel paste or the like is applied by a screen printing method. Next, in step S2, partition walls are printed. Similarly, by using screen printing, a desired partition wall height is obtained by repeatedly applying glass paste or the like and applying it repeatedly. However, it is preferable to set the printing height in consideration of the polishing amount in advance. Next, in step S3, the plasma electrode and the partition printed according to a predetermined temperature profile are simultaneously fired.

FIG. 4 shows the height and width dimensions of the plasma electrode and the partition walls formed at this stage. In this example, the plasma electrodes 1 have a width of 300 μm and are arranged in stripes at a pitch of 410 μm. On the other hand, the partition wall 3 has a width dimension of 100 μm, and the height dimension from the surface of the substrate 2 to the top is set to 200 μm. Partition wall 3
Has a wall shape with a height dimension larger than a width dimension, and its mechanical strength is not so high. Therefore, if it is directly subjected to a polishing treatment, it may be damaged or collapsed.

Returning to the flowchart of FIG. 3 again, step S
In step 4, the temporary reinforcing material is filled. In this example, a water-soluble UV curable resin (3046B) manufactured by ThreeBond is used,
Application was performed by atomizing with a spray. Then, it is irradiated with ultraviolet rays to be cured. By repeating this application and irradiation several times, the temporary reinforcing material is filled up to a height level of 160 to 170 μm, and the periphery of each partition wall is embedded. Note that FIG. 4 schematically shows the relationship between the height dimension of the partition wall 3 and the height level of the temporary reinforcing member 4. The UV curable resin may be applied by a dip method instead of the spray method. When dipping is performed, it is preferable to select the pulling direction to be a direction orthogonal to the stripes of the partition walls. If the substrate is pulled up in a direction parallel to the stripes, uneven thickness will occur between the upper side and the lower side.

Next, in step S5, a polishing process is performed. In this example, a polishing process was performed using a single-side polishing machine for a glass substrate of a liquid crystal display device (for example, SP-800 manufactured by Speed Fam Co.). FIG. 5 shows a perspective external structure of the single-side polishing machine. A pair of arms 22 are attached to the upper surface of the rotary grindstone plate 21. A pressure plate 23 is attached to the lower surface of each arm 22. This pressure plate 2
The substrate 2 to be polished is fixed to the back surface of the substrate 3.

FIG. 6 is a schematic plan view showing a polishing operation of the single-sided polishing machine shown in FIG. As shown in the figure, the rotary grindstone plate 21 rotates bidirectionally around the shaft 24. On the other hand, the pair of arms 22 is the shaft 2
It swings in the direction parallel to the rotary grindstone plate 21 around the center 5. As a result, the tops of the partition walls provided on the substrate 2 fixed to the back surface of the pressure plate 23 can be uniformly polished. In this example, WA # 2000 is used as the abrasive, and 0.3 kg is applied to the pressure plate 23.
A pressure of f was applied, the number of rotations of the rotary grindstone plate 21 was set to 25 rpm, and the number of swings of the pair of arms 22 was set to 4 rpm. By polishing for 10 to 15 seconds, about 20
The top of the partition wall of μm could be ground.

Returning to the flowchart of FIG. 3 again, step S6
Then, the UV curable resin is washed. This cleaning is about 8
Ultrasonic waves and rocking were added using warm water of 0 ° C. 1
The UV curable resin could be peeled off almost completely by the washing treatment for about 5 minutes. After that, the washing liquid was replaced with warm water by IPA to eliminate unevenness in drying. After this, in step S7, frit sealing was performed to bond the polished substrate to the intermediate sheet, and an ionizable gas was sealed inside to assemble a plasma cell. Finally, in step S8, a liquid crystal cell was assembled on the upper surface side of the intermediate sheet to complete a plasma addressed liquid crystal display device.

FIG. 8 is a flow chart showing another specific example of the method of manufacturing a plasma addressed liquid crystal display device according to the present invention. Basically, it is the same as the previous specific example shown in FIG. The difference is that water-soluble polyethylene glycol is used as the temporary reinforcing material instead of the water-soluble UV-curable resin. Note that this material is thermoplastic. First, in step S1, the plasma electrodes are printed. Next step S
At 2, print the septum. Next, in step S3, the printed plasma electrodes and barrier ribs are simultaneously fired. After this, in steps S41, S42 and S43, the temporary reinforcing material is filled.
Here, water-soluble polyethylene glycol (PEG) is prepared as a temporary reinforcing material. For example, the trade name PEG1540 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. can be used. Or Union Carbide Chemicals and
Product name CA supplied by Plastics Co., Ltd.
RBO-WAX1450 can be used. Both
It is thermoplastic with a melting temperature of 45 ° C to 50 ° C and is completely water-soluble. First, in step S41, polyethylene glycol is supplied to the substrate on which the plasma electrode and the partition are formed in advance. The substrate is placed on the hot plate, and the supplied polyethylene glycol is in a molten state. Subsequently, in step S42, the substrate is heated by an electric path to flatten the surface of polyethylene glycol. By heating the substrate at a temperature about 5 ° C. higher than the melting temperature of polyethylene glycol, the surface tension acts to flatten the surface of the molten polyethylene glycol. Next step S
The substrate is cooled at 43. If the substrate is rapidly cooled, the surface of the polyethylene may crack when the polyethylene glycol is solidified. When the filling process of the temporary reinforcing material is completed in this way, the process proceeds to step S5 and the polishing process is performed. Next, in step S6, the water-soluble polyethylene glycol is washed. After this, in step S7, frit sealing is performed to bond the polished substrate to the intermediate sheet, and an ionizable gas is sealed inside to assemble a plasma cell. Finally, in step S8, a liquid crystal cell is assembled on the upper surface side of the intermediate sheet to complete a plasma addressed liquid crystal display device.

FIG. 9 is a schematic partial sectional view showing a filled state of the temporary reinforcing material 4 made of polyethylene glycol. In this example, polyethylene glycol is applied thickly so as to cover the entire partition wall 3. As described above, since the surface of the temporary reinforcing material 4 made of polyethylene glycol is flattened, uniform and reliable polishing can be performed.
Also, since polyethylene glycol is completely water soluble,
It can be removed fairly cleanly by washing with water only. Therefore, it does not adversely affect the plasma discharge. Unlike UV curable resin, no special equipment such as UV lamp is required. Polyethylene glycol itself is a chemically safe material.

In the two examples described above, a water-soluble ultraviolet curable resin or a thermoplastic resin such as polyethylene glycol is used as the temporary reinforcing material. The optimum temporary reinforcing material may be selected according to individual manufacturing conditions, and the present invention is not limited to the disclosed resin material. It should be noted that when the ultraviolet curable resin is used, the peeling amount of the temporary reinforcing material varies depending on the viscosity. If the viscosity is relatively high, the temporary reinforcement will not dissolve in water, but rather will tend to peel off with water. For this reason, there is a case where the role of the temporary reinforcing material is not fulfilled at the time of polishing. Further, when the viscosity is relatively low, the resin taken out by water may be solidified, and the polishing agent may be taken in during polishing to damage the partition walls. When using polyethylene glycol, these difficulties do not occur.

[0021]

As described above, according to the present invention, by filling a temporary reinforcing material such as an ultraviolet curable resin or polyethylene glycol, the strength is increased to polish the top of the partition wall, and then the temporary reinforcing material is used. By removing the barrier ribs, it was possible to form partition walls with high yield and uniform height. The finishing accuracy (flatness) of polishing was improved, and it became possible to uniformly control the gap unevenness after bonding with the liquid crystal cell side to 0.1 μm or less.

[Brief description of drawings]

FIG. 1 is a basic process diagram showing a method of manufacturing a plasma addressed liquid crystal display device according to the present invention.

FIG. 2 is a schematic cross-sectional view showing a completed product state of a plasma addressed liquid crystal display device manufactured according to the present invention.

FIG. 3 is a flowchart showing a specific example of a method for manufacturing a plasma addressed liquid crystal display device according to the present invention.

FIG. 4 is an explanatory diagram showing specific dimensions of partition walls and plasma electrodes.

FIG. 5 is an external perspective view of a single-sided polishing machine used for a polishing process.

FIG. 6 is a plan view of the single-sided polishing machine.

FIG. 7 is a cross-sectional view showing a conventional plasma addressed liquid crystal display device.

FIG. 8 is a flowchart showing another specific example of the method of manufacturing a plasma addressed liquid crystal display device according to the present invention.

FIG. 9 is a schematic cross-sectional view showing a filled state of a temporary reinforcing material.

[Explanation of symbols]

 1 Plasma Electrode 2 Substrate 3 Partition 4 Temporary Reinforcing Material 11 Liquid Crystal Cell 12 Plasma Cell 13 Intermediate Sheet

Claims (5)

[Claims] 1. A method of manufacturing a plasma addressed liquid crystal display device in which a plasma cell and a liquid crystal cell are superposed on each other via an intermediate sheet, and a partition forming step of printing and forming a stripe-shaped partition on a substrate on which a plasma electrode is formed in advance. And a temporary reinforcing step of filling a temporary reinforcing material between the stripe-shaped partition walls to fill the periphery of each partition wall, a polishing step of polishing and flattening the top of each partition wall in the embedded state, and the temporary reinforcing Plasma addressed liquid crystal display characterized by performing a removing step of removing a material to expose a plasma electrode and a joining step of assembling a plasma cell by abutting on a flattened top of each partition wall and joining the intermediate sheet. Device manufacturing method. 2. The method of manufacturing a plasma addressed liquid crystal display device according to claim 1, wherein in the temporary reinforcing step, an ultraviolet curable resin is supplied to the substrate and then a curing process is performed to form the temporary reinforcing material. . 3. The method of manufacturing a plasma addressed liquid crystal display device according to claim 2, wherein in the removing step, the temporary reinforcing material made of the ultraviolet curable resin is dissolved in agitated warm water. 4. The temporary reinforcing step is characterized in that the temporary reinforcing material is filled at a height level of not less than half the height of the printed partition wall and not more than the polishing amount at the top of the partition wall. A method for manufacturing the plasma addressed liquid crystal display device described. 5. The method of manufacturing a plasma addressed liquid crystal display device according to claim 1, wherein the temporary reinforcing step uses water-soluble polyethylene glycol as a temporary reinforcing material.