JPH0743692A - Plasma address liquid crystal display device - Google Patents

Abstract

PURPOSE:To suppress crosstalks by lowering the capacitance coupling between the discharge electrodes on a plasma cell side and the signal electrodes on a liquid crystal cell side. CONSTITUTION:The liquid crystal cell 2 and the plasma cell 3 are superposed on each other via an intermediate dielectric sheet 1. The liquid crystal cell 2 consists of an upper substrate 4 adhered via a prescribed spacing to one surface side of the dielectric sheet 1 and a liquid crystal layer 5 held in this spacing. The column signal electrodes 6 are formed on the inside surface of the upper substrate 4. The plasma cell 3 consists of the lower substrate 7 joined via a prescribed spacing to the other surface side of the dielectric sheet 1 and a row scanning channel 8 disposed in this space. This row scanning channel 8 is composed of partition walls 9 which partition the spaces to a row form and the row discharge electrodes 10 disposed in parallel therewith. The partition walls 9 consist of a high-polymer resin patterned and formed to a stripe shape and has the lower dielectric constant than the dielectric constant of glass, etc.

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 having a two-layer structure of a liquid crystal cell and a plasma cell. More specifically, it relates to a scan channel structure of a plasma cell.

[0002]

2. Description of the Related Art A plasma addressed liquid crystal display device is disclosed in, for example, Japanese Patent Application Laid-Open No. 1-217396, and its structure is shown in FIG. This device has a laminated flat panel structure composed of a liquid crystal cell 101, a plasma cell 102, and a common dielectric sheet 103 located between them. The plasma cell 102 is formed using a glass substrate 104, and stripe-shaped grooves 105 are provided on the surface thereof. The grooves 105 extend, for example, in the row direction of the matrix. Each groove 105 is a dielectric sheet 10
3 form individually separated row scan channels 106. The sealed row scan channel 106 is filled with an ionizable gas. The convex portion 107 that separates the adjacent grooves 105 serves as a partition that separates the individual row scanning channels 106. Each groove 10
A pair of discharge electrodes that are parallel to each other are provided on the curved bottom portion of 5 and function as an anode A and a cathode K to ionize the gas in the row scanning channel 106 and generate discharge plasma. On the other hand, the liquid crystal cell 101 is a glass substrate 10.
8 is used. The substrate 108 is arranged to face the dielectric sheet 103 with a predetermined gap, and the liquid crystal layer 109 is held in the gap. Column signal electrodes 110 are formed on the inner surface of the substrate 108. The column signal electrodes 110 are orthogonal to the row scanning channels 106, and matrix-shaped pixels are defined at the intersections.

Next, a method of manufacturing the plasma addressed liquid crystal display device shown in FIG. 5 will be briefly described. First, the groove 105 is formed in the glass substrate 104. This is performed by chemical etching using, for example, hydrofluoric acid or borofluoric acid as an etchant. The portion left by etching becomes the convex portion 107 and plays the role of a partition. Next, an electrode material is applied as a film by a sputtering vapor deposition method or the like, and patterned by photolithography and etching to form an anode A and a cathode K. The glass substrate 104 having the groove formed therein and the dielectric sheet 103 are bonded to each other. The dielectric sheet 103 is made of, for example, thin glass, and is sealed on the lower glass substrate 104 with frit glass or the like so as to maintain airtightness. Then, the sealed groove 10
The inside of 5 is replaced with a predetermined gas, and the exhaust port is sealed. Finally, the upper glass substrate 108 on which color filters and column signal electrodes are formed in advance is attached to the dielectric sheet 103 with a predetermined gap. A plasma addressed liquid crystal display device is completed by injecting liquid crystal into this gap.

Next, the operation of the apparatus shown in FIG. 5 will be briefly described. In the plasma addressed liquid crystal display device, the row scan channel 106 in which plasma discharge is performed is line-sequentially switched and scanned, and an image signal is applied to the column signal electrode 110 on the liquid crystal cell side in synchronization with this scan to drive the display. Is performed. When a plasma discharge is generated in the row scanning channel 106, the inside has a substantially uniform anode potential and pixel selection for each row is performed. That is, the row scan channel 106 functions as a sampling switch. When an image signal is applied to each pixel while the plasma sampling switch is in a conductive state, sampling hold is performed, and lighting or extinguishing of the pixel can be controlled. Even after the plasma sampling switch is turned off, the image signal is held in the pixel as it is.

FIG. 6 is a schematic sectional view showing another example of a conventional plasma addressed liquid crystal display device, which is disclosed in, for example, Japanese Patent Application Laid-Open No. 4-265931. This display device also has a flat panel structure in which a liquid crystal cell 201 and a plasma cell 202 are laminated with an intermediate dielectric sheet 203 made of thin glass plate or the like interposed therebetween. The liquid crystal cell 201 has basically the same structure as the liquid crystal cell 101 shown in FIG. On the other hand, in the plasma cell 202, an ionizable gas is sealed between the dielectric sheet 203 and the lower glass substrate 204. Striped discharge electrodes 206 are formed on the inner surface of the glass substrate 204. The discharge electrode 206 is formed by a screen printing method using Ni paste or the like. A partition wall 20 is provided on the discharge electrode 206.
7 are formed, and the space in which the ionizable gas is enclosed is divided along the row direction to form the row scanning channel 205. This partition wall 207 can also be formed by a screen printing method using glass paste or the like, and its top portion is in contact with the lower surface side of the dielectric sheet 203. The striped discharge electrodes 206 alternately function as the anode A and the cathode K, and generate a plasma discharge between them.

[0006]

In any of the structures shown in FIGS. 5 and 6, a floating potential is generated in the row scanning channel during a period (non-selection period) in which plasma discharge is not performed, and a column on the liquid crystal cell side is formed. It is electrically separated from the signal electrode.
However, in reality, a dielectric material such as a liquid crystal layer, a dielectric sheet, and a partition is interposed between the column signal electrode and the discharge electrode, and there is capacitive coupling. In particular, in the conventional example shown in FIGS. 5 and 6, each partition wall is made of a glass material, and the dielectric constant is about 6 to 7, which is relatively large. Therefore, the capacitive coupling between the signal electrode and the discharge electrode cannot be ignored, and the ratio of the image signal applied to the liquid crystal layer increases even in the non-selected period, which causes a problem of crosstalk. Further, in the conventional structure shown in FIG. 5, the convex portions to be the grooves and the partition walls are formed by chemical etching. In order to perform uniform etching, it is necessary to strictly control etchant circulation and temperature, but there are limits in the actual process. Therefore,
There is a problem in that there is a large variation between lots and it is difficult to always obtain a uniform partition structure. Further, since a strong acid is used as an etchant, there is a problem in safety in the manufacturing process. On the other hand, in the conventional example shown in FIG. 6, the partition walls are formed by screen printing, but the pattern accuracy is poor because the screen expands and contracts during printing and the substrate shrinks during firing. Therefore, there is a problem that a pitch shift or the like occurs between the discharge electrode and the partition wall, and the plasma discharge becomes nonuniform.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems of the conventional technique, the following means were taken. That is, the plasma addressed liquid crystal display device according to the present invention has, as a basic configuration, a laminated structure including a liquid crystal cell and a plasma cell which are stacked with an intermediate dielectric sheet interposed therebetween. The liquid crystal cell is composed of an upper substrate bonded to one side of the dielectric sheet with a predetermined gap, and a liquid crystal layer held in the gap.
Column signal electrodes are formed on the inner surface of the upper substrate. On the other hand, the plasma cell includes a lower substrate joined to the other surface side of the dielectric sheet via a predetermined space, and a row scanning channel provided in the space. The row scanning channel is composed of partition walls partitioning the space into rows and row discharge electrodes arranged in parallel with the partition walls. In this structure, the partition wall is made of a polymer resin patterned in a stripe pattern. As the polymer resin, for example, a polyimide resin can be used. The polymer resin is covered with an inorganic film made of SiO ₂ or the like.

The plasma addressed liquid crystal display device having such a structure is manufactured by the following method. That is, the first step of forming the row discharge electrodes on the lower substrate is first performed. Next, after forming a polymer resin film on the lower substrate, a second step is performed in which the polymer resin is patterned in a stripe shape by photolithography to form partition walls parallel to the row discharge electrodes. Next, with the tops of the partition walls in contact with each other, the lower substrate is bonded to one surface side of the dielectric sheet prepared in advance, and a space defined by adjacent partition walls is filled with an ionizable gas so that a row scanning channel is formed. Is carried out. Finally, a fourth step is performed in which the upper substrate on which the column signal electrodes are formed is adhered to the other surface side of the dielectric sheet through a predetermined gap, and liquid crystal is sealed in the gap. Preferably, the second step is a step of forming a film of a photosensitive polymer resin and directly patterning this into a stripe pattern by photolithography. Instead of this, the second step may be to form a non-photosensitive polymer resin film, and then perform photolithography and etching using a resist to perform patterning in stripes.

[0009]

According to the present invention, the partition wall provided in the plasma cell is formed by patterning a polymer resin such as polyimide by photolithography. The permittivity of polymer resin is the permittivity of glass (about 6 to
Compared to 7), the dielectric constant of polyimide is about 3
Is. Therefore, the coupling capacitance interposed between the discharge electrode and the signal electrode is correspondingly reduced, and electrical separation is ensured. Since the voltage applied to the liquid crystal is reduced during the non-selection period, crosstalk can be effectively reduced. Preferably, a polymer resin such as polyimide is covered with an inorganic film such as SiO ₂ to prevent the adverse effect of outgas. A thickness of about 0.01 μm is sufficient for the inorganic film, and the thickness of the partition wall made of polymer resin (for example, 150 μm).
It is extremely thin compared to (μm). Therefore, even if the inorganic film is covered, the effect on the crosstalk can be ignored.

According to the manufacturing method of the present invention, the partition wall is formed by patterning a polymer resin by photolithography. Therefore, patterning can be performed with higher accuracy than screen printing or the like. Further, since the top of the partition wall has a good flatness, an extremely flat plane can be obtained even when the glass substrate on which the partition wall is formed by a frit seal or the like and the dielectric sheet made of an intermediate thin glass plate are bonded to each other. In particular, when polyimide is used as the polymer resin, its heat resistance is extremely high, and it can withstand a temperature of, for example, 500 ° C. for 1 hour or more. Therefore, when the dielectric sheet and the glass substrate are joined by the glass frit seal, a heat treatment at 450 ° C. for about 15 minutes is added, but no problem occurs.

[0011]

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 schematic sectional view showing the basic structure of a plasma addressed liquid crystal display device according to the present invention. As shown in the figure, this device has a laminated structure composed of a liquid crystal cell 2 and a plasma cell 3 which are stacked with an intermediate dielectric sheet 1 interposed therebetween. The dielectric sheet 1 is made of, for example, thin glass plate and has a thickness of about 50 μm. The liquid crystal cell 2 is composed of an upper glass substrate 4 bonded to one surface side of the dielectric sheet 1 with a predetermined gap, and a liquid crystal layer 5 held in the gap. This gap size is, for example, 5
The liquid crystal layer 5 is, for example, twisted nematically aligned. Column signal electrodes 6 are formed on the inner surface of the upper substrate 4. This column signal electrode 6 is, for example, IT
A transparent conductive film such as O is patterned in a stripe shape. In the case of a color liquid crystal display device, stripe-shaped color filters are formed on the inner surface of the upper substrate 4.

On the other hand, the plasma cell 3 comprises a lower glass substrate 7 bonded to the other surface side of the dielectric sheet 1 through a predetermined space, and a row scanning channel 8 provided in the space. There is. The row scanning channel 8 includes partition walls 9 that partition the space into rows, and row discharge electrodes 1 arranged in parallel with the partition walls 9.
It is composed of 0 and. The height of the barrier ribs 9 is, for example, about 150 μm, and the discharge electrodes 10 are arranged at intervals of 20.
It is about 0 μm. In this example, the barrier ribs 9 are provided on the discharge electrodes 10 in alignment with each other. Therefore, the pair of discharge electrodes 10 adjacent to each other exposed in one row scanning channel 8 function as the anode A and the cathode K. The present invention is not limited to such a structure, and a pair of anodes A and cathodes K may be provided in the row scanning channels 8 surrounded by the pair of partition walls 9 adjacent to each other. An ionizable gas is enclosed inside the row scanning channel 8. The gas species can be selected from, for example, helium, neon, argon or a mixed gas thereof.

As a feature of the present invention, the partition wall 9 is made of a polymer resin which is patterned in stripes by photolithography. As the polymer resin, for example, a polyimide resin can be selected. This polymer resin is an inorganic film 1
It is covered by 1. This inorganic film 11 is, for example, Si
O ₂ can be deposited by sputtering. As can be understood from the structure shown, the discharge electrode 10 and the signal electrode 6
The liquid crystal layer 5, the dielectric sheet 1, and the partition wall 9 are interposed between and, and capacitive coupling exists. However, the partition wall 9 is made of a polymer resin such as polyimide, and its dielectric constant is smaller than that of conventional partition wall material such as glass. Therefore, it is possible to suppress the capacitive coupling to be low, and it is possible to effectively reduce the crosstalk at the time of non-selection, which has been a problem in the past.

Next, a method of manufacturing the plasma addressed liquid crystal display device shown in FIG. 1 will be described in detail with reference to FIGS. First, in step A of FIG. 2, a discharge electrode 10 is formed by depositing a metal film on the surface of the lower glass substrate 7 by a sputtering method or an evaporation method and patterning it in stripes by photolithography and etching. For example, nickel can be selected as the electrode material. The polymer resin 12 is applied thereon by spin coating or printing. In this example, a negative photosensitive polyimide (Photo Nice UR-5100 manufactured by Toray) was applied. After coating, prebaking is performed at 80 ° C. for 60 minutes in a clean oven.

Next, in step B, the film is exposed to ultraviolet rays of about 250 mj / cm ² through a mask 13 having a predetermined stripe pattern.

Next, in step C, development processing is performed. For example, Toray DV-605 (NMP, xylene type) was used as the developing solution, and the dipping method or spraying method was adopted. Then, rinse with isopropanol for about 10 seconds, and finally calcination. The firing profile is, for example, 135 ° C.
× 30 minutes + 200 ° C × 30 minutes + 300 ° C × 30 minutes +40
It is 0 ° C. × 30 minutes. In this way, the partition wall 9 having a height of about 50 μm can be formed. Generally, in order to obtain stable glow discharge in the scanning channel, it is necessary to secure the height of the barrier ribs at 75% or more of the distance between the discharge electrodes. For example,
When the distance between the discharge electrodes is 200 μm, the barrier rib height of 150 μm or more is required. Therefore, in order to form a partition wall having a height of 150 μm, the above-described steps A, B and C are performed three times.
Just repeat it. In this way, as shown in step D, the partition wall 9 having a desired height can be formed.

Next, as shown in step E of FIG. 3, after the partition wall is formed, its surface is covered with an inorganic film 11 in order to prevent outgas from the polyimide. In this example, SiO ₂ was deposited by sputtering. Sputtering scatters target molecules from random directions, so that SiO ₂ can be deposited also on the side surfaces of the partition walls 9 positioned in the direction perpendicular to the substrate 7.

Next, in step F, the lower glass substrate 7 is bonded to one side of the dielectric sheet 1 prepared in advance with the tops of the partition walls 9 in contact with each other. In this example, the dielectric sheet 1 was made of thin glass and was joined using the frit seal 14. Subsequently, the space defined by the adjacent partition walls 9 is filled with an ionizable gas, and the row scanning channel 8 is provided.
To provide. At this time, the firing condition for the frit seal is 450.
It takes about 15 minutes at ℃. On the other hand, the heat resistance of the polyimide forming the partition wall 9 is 500 ° C. for 1 hour or longer, and no problem occurs.

Finally, in step G, the column signal electrodes 6 are previously prepared.
The upper glass substrate 4 on which is formed is adhered to the other surface side of the dielectric sheet 1 through a predetermined gap. In this example, the adhesive 15
As the material, a thermosetting resin or an ultraviolet curable resin can be used. Finally, the liquid crystal 5 is sealed in the gap to complete the plasma addressed liquid crystal display device. In the present invention, since the barrier ribs 9 are formed by photolithography, patterning can be performed with high accuracy, and therefore no positional deviation with the discharge electrode 10 occurs. Further, the height dimension of the partition wall 9 can be controlled with high accuracy, and
Its top also has excellent flatness. Therefore, the contact with the dielectric sheet 1 in an extremely flat relationship does not cause unevenness on the surface. Therefore, the thickness of the liquid crystal layer 5 can be uniformly controlled over the entire substrate.

FIG. 4 is a process chart showing another method of manufacturing the plasma addressed liquid crystal display device shown in FIG. First, in step A, the discharge electrodes 10 are patterned in stripes on the surface of the lower glass substrate 7. Then, a non-photosensitive polyimide resin 16 is applied as a polymer resin material. In this example, Toray's Semico Fine SP
-110 was applied by printing. Then 150 ℃ x 30 minutes +
(200 to 300 ° C.) Bake with a temperature profile of 30 minutes. Similar to the manufacturing method shown in FIG. 2, in order to obtain a desired thickness, it is necessary to overcoat the polyimide resin 16.

Next, in step B, a positive resist 17 is formed on the surface of the baked polyimide resin 16. In this example, OFPR- made by Tokyo Ohka is used as a positive resist.
800 was used. Subsequently, the positive resist 17 is exposed using the mask 18 having a stripe pattern.

Next, in step C, the positive type resist 17 is used.
Development processing is performed. In this way, a stripe pattern that matches the discharge electrode 10 is formed.

Next, in step D, the partition walls 9 are formed by etching the polyimide resin using the positive resist 17 patterned in stripes as a mask.
In this example, hydrazine was used as the etchant.

Finally, in step E, the used positive resist is peeled off, and then baked at 350 ° C. for 30 minutes. Finally, SiO ₂ is deposited by sputtering and the surface of the partition 9 is covered with the inorganic film 11. After that, the plasma addressed liquid crystal display device can be assembled in the same manner as the previous example shown in FIG.

[0025]

As described above, according to the present invention, the partition for partitioning the row scanning channels of the plasma cell is formed of a polymer resin such as polyimide, and has a higher dielectric constant than a partition made of conventional glass. Since the ratio is small, there is an effect that capacitive coupling between the discharge electrode on the plasma cell side and the signal electrode on the liquid crystal cell side can be reduced, and crosstalk can be effectively suppressed. Further, since the polymer resin is patterned by photolithography to form the partition walls, there is an effect that the precision is high and the high definition can be easily achieved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a basic configuration of a plasma addressed liquid crystal display device according to the present invention.

FIG. 2 is a manufacturing process diagram of the plasma addressed liquid crystal display device shown in FIG.

FIG. 3 is likewise a manufacturing process drawing.

FIG. 4 is a process drawing showing another manufacturing method of the plasma addressed liquid crystal display device shown in FIG.

FIG. 5 is a cross-sectional view showing an example of a conventional plasma addressed liquid crystal display device.

FIG. 6 is a cross-sectional view showing another example of a conventional plasma addressed liquid crystal display device.

[Explanation of symbols]

 1 Dielectric Sheet 2 Liquid Crystal Cell 3 Plasma Cell 4 Upper Substrate 5 Liquid Crystal Layer 6 Column Signal Electrode 7 Lower Substrate 8 Row Scanning Channel 9 Partition 10 Discharge Electrode 11 Inorganic Film 12 Photosensitive Polyimide Resin 16 Non-Photosensitive Polyimide Resin

Claims (6)

[Claims] 1. A laminated structure composed of a liquid crystal cell and a plasma cell, which are stacked via an intermediate dielectric sheet, wherein the liquid crystal cell is adhered to one surface side of the dielectric sheet with a predetermined gap. Further, the lower substrate is composed of an upper substrate having column signal electrodes formed on the inner surface thereof and a liquid crystal layer held in the gap, and the plasma cell is joined to the other surface of the dielectric sheet through a predetermined space. And row scanning channels provided in the space. The row scanning channels are composed of partition walls partitioning the space into rows and row discharge electrodes arranged in parallel with the partition walls, and the partition walls are patterned in stripes. A plasma addressed liquid crystal display device made of a formed polymer resin. 2. The plasma addressed liquid crystal display device according to claim 1, wherein the polymer resin is a polyimide resin. 3. The plasma addressed liquid crystal display device according to claim 1, wherein the polymer resin is covered with an inorganic film. 4. A first step of forming a row discharge electrode on a lower substrate, and a step of forming the polymer resin on the lower substrate and then patterning the polymer resin in a stripe shape by photolithography. A second step of providing barrier ribs parallel to the discharge electrodes, and with the top of the barrier ribs in contact with each other, the lower substrate is bonded to one surface side of a dielectric sheet prepared in advance, and ionized into a space partitioned by adjacent barrier ribs. The third step of enclosing a possible gas to provide a row scanning channel, and adhering an upper substrate, on which column signal electrodes are formed in advance, to the other surface side of the dielectric sheet through a predetermined gap, and filling a liquid crystal in the gap. A method of manufacturing a plasma addressed liquid crystal display device, which comprises a fourth step of encapsulation. 5. The method for manufacturing a plasma addressed liquid crystal display device according to claim 4, wherein in the second step, a photosensitive polymer resin is formed into a film, and the film is directly patterned by photolithography in a stripe shape. 6. The plasma addressed liquid crystal display device according to claim 4, wherein in the second step, after a non-photosensitive polymer resin is formed into a film, photolithography and etching are performed using a resist to perform patterning in stripes. Production method.