JP2003287761A - Cell capping device and method for manufacturing liquid crystal cell using the capping device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that in a liquid crystal cell having in-seal-spacers within a sealant for bonding a pair of substrates without distributing the spacers in an optically effective area, the cross section of the cell has a center dented shape and it is difficult to cap the cell while a uniform cell gap is maintained by a conventional pressure capping method. <P>SOLUTION: First and second substrates are pulled by an upper vacuum sucking table and a lower vacuum sucking table to be reformed and as a result the cell can be easily capped while the uniform prescribed cell gap is maintained, since the cell whose cross section has the center dented shape is sucked by the sucking tables while being pressure maintained in the liquid crystal capping device and the capping method. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is for sealing a cell by injecting a liquid crystal material into a cell in which two transparent substrates are superposed on each other via a sealing material to realize a predetermined target cell gap. The present invention relates to a cell sealing device and a method of manufacturing a liquid crystal cell using the cell sealing device.

[0002]

2. Description of the Related Art Liquid crystal cells include monochrome, color,
The structure differs depending on the active type, passive type, TN type, STN type, ferroelectric type, antiferroelectric type, etc. In the following description, an STN passive type monochrome liquid crystal cell will be described as a typical example. Usually, a cell is constructed by laminating a pair of substrates having a transparent electrode inside with a sealing material interposed therebetween. Further, in order to make the pair of substrates have a uniform interval, it is common to dispose an internal spacer in the optically effective region of the cell and further mix the spacer in the sealing material.

However, in this cell structure, since the internal spacer exists on the transparent electrode pattern which is the optically effective area, there is a portion where the optical effect of the liquid crystal material cannot be obtained. Furthermore, the alignment disorder of the liquid crystal material is generated around the internal spacers, and the function as a liquid crystal cell is significantly deteriorated. Especially diagonal 10m
When the liquid crystal cell is used as a small-sized liquid crystal cell having a small optically effective area of about m or less, or as an optical element for modulating a laser beam having a small spot diameter, the effect becomes remarkable.

Therefore, in order to solve these problems, the inner spacers are selectively distributed in the cell, and the inner spacers are not arranged on the transparent electrode pattern, which is the optically effective region thereof, or in the seal. There is a method of manufacturing a liquid crystal cell in which the cell gap is held only by the spacer.
Here, a cell in which the cell gap is held only by the spacer in the seal will be described below.

FIG. 8A is a plan view showing the structure of a liquid crystal cell manufactured by holding the cell gap only by the in-seal spacer 24, and FIG. 8B is a sectional view taken along line CC of FIG. 8A. It is a figure. The cell made with the configuration shown in FIG.
Since the in-seal spacer 24 is disposed only in the inner space 3 and the optically effective area 31 does not have an obstacle as an inner spacer, the function loss of the liquid crystal cell due to the inner spacer is eliminated. Therefore, this structure is effective for a small-sized liquid crystal cell, especially when the influence of optical characteristics is large. The method for manufacturing the cell shown in FIG. 8 will be described below.

FIG. 6A is a plan view showing the arrangement of a plurality of cells formed on a large-sized substrate as seen from the top surface of the cell.
FIG. 6B is a sectional view taken along line BB of FIG. Note that FIG.
In FIG. 6A and FIG. 6B, the parts other than the sealing material 23 are omitted. Since a transparent substrate normally takes out a plurality of cells at a time, a large substrate on which a plurality of electrode patterns of independent pixels are patterned is used as shown in FIG. That is, 28 liquid crystal cells can be finally manufactured from the transparent substrate of FIG.

First, a transparent electrode pattern (not shown) is formed in the optically effective area 31 on the first substrate 33. Next, an alignment film (not shown) for determining the alignment direction of the liquid crystal material is formed on the transparent electrode. Further, a transparent electrode pattern and an alignment film (not shown) are also formed on the second substrate 34.

Further, the optically effective area 3 of the first substrate 33
A thermosetting sealing material 23 for adhering and sealing the first substrate 33 and the second substrate 34 is provided on the peripheral portion 1 by a printing method. As described above, the sealant 23 is preliminarily mixed with an in-seal spacer for keeping the gap between the first substrate 33 and the second substrate 34 uniform.

Next, the first substrate 33 and the second substrate 3 are formed so that the pixels provided on both substrates can form effective pixels.
Stack 4 Thereafter, the stacked substrates are fired under pressure to form a pair of substrates in which a plurality of cells are integrated as shown in FIG. 6B in a cell gap forming step of curing the sealing material to a predetermined uniform gap. To do. By the way, this cell has the sealing material 23 in the cell gap forming step.
Is cured and shrunk to a size smaller than the size in the printing stage, so that the first substrate 33 and the second substrate 34 are distorted.

Due to the distortion of the substrate in such a cell,
The substrate dents inside the cell. As a result, the cross section of the cell has the shape of a hollow frame shown in FIG.

Further, when a single cell is small and the number of cells to be taken is large, the liquid crystal injection hole 32 is normally aligned in the direction in which the liquid crystal material can be injected to form a strip shape in which a plurality of cells are connected. cut. FIG. 7A shows a rectangular cell cut out from the pair of large substrates shown in FIG. In this case, the number of single cells included in the strip-shaped cells is four in the figure.

Next, the liquid crystal material is simultaneously injected into the strip-shaped cells taken out from the respective liquid crystal injection holes 32.
Injection and sealing of the liquid crystal material in such a medium-bevel shaped cell are performed as follows. That is, after injecting a liquid crystal material into the cell through the liquid crystal injection hole 32 while maintaining the above-mentioned middle solid state, the first substrate 33 and the second substrate 34 are sufficiently deformed to form a predetermined cell gap. Pressure is applied from the outside of both substrates to eliminate excess liquid crystal material in the cell. Next, the liquid crystal injection hole 32 is sealed with a sealing material such as an ultraviolet curable resin to loosen the pressure from the outside. In this case, the distortion of the substrate is corrected by the negative pressure in the cell, and the negative pressure causes the gap of the cell to be a target distance. The cell sealing method as described above is generally called a pressure sealing method. A strip-shaped liquid crystal cell is completed through the above steps.

Finally, individual liquid crystal cell pattern boundaries are separated and cut from the strip-shaped liquid crystal cell, as shown in FIG.
A plurality of single liquid crystal cells shown in are taken out. After that, the single liquid crystal cell was attached with a polarizing film, IC or FP.
It becomes a module and can be driven by mounting C, mounting a backlight, and the like.

[0014]

However, even if the liquid crystal material is injected into the cell having a medium-bevel shape in the above-described cell gap forming step and the cell is subjected to the sealing treatment by the pressure sealing method, Since the cells are originally formed in a middle shape, it is possible to deform the first substrate 33 and the second substrate 34 of the cells so that the cell gap has a target distance, and the cells are subjected to sealing treatment at uniform intervals. It will be very difficult. In other words, even if the liquid crystal is injected in the medium bevel shape, the internal pressure and the outer pressure of the cell are the same, so the force to return to the original medium bevel shape works after the liquid crystal is injected, and the distortion of the substrate is completely corrected. Because you can't do that. Therefore, for the above reason, the intended cell gap cannot be formed, and the function as a liquid crystal cell is significantly deteriorated.

[Object of the Invention] An object of the present invention is to solve the above problems and to provide a liquid crystal cell whose cross-sectional shape is a mid-bevel shape, in which the cell gap is maintained only by the spacer in the seal mixed in the sealing material. It is an object of the present invention to provide a cell sealing device for realizing a predetermined uniform target cell gap and sealing a liquid crystal injection hole, and a method of manufacturing a liquid crystal cell using the device.

[0016]

In order to achieve the above object, a cell sealing device of the present invention and a method of manufacturing a liquid crystal cell using the sealing device adopt the following constitution.

The cell sealing device of the present invention is a cell sealing device for sealing a liquid crystal material after injecting the liquid crystal material from an injection hole of a cell formed by connecting a pair of substrates through a sealing material. It is characterized in that the injection hole can be sealed with a sealing material in a state where the pair of substrates of the cell are respectively sucked by the vacuum suction table and the other vacuum suction table.

Further, the cell is pressurized and held, and one of the vacuum suction tables is fixed to the apparatus main body, and the other is operated by an air bag to perform the pressure. In addition, the other vacuum suction table is arranged on the pressure table, and the guide bush that operates vertically along the cylinder enables the other vacuum suction table to be operated up and down together with the pressure table. Is characterized by.

Further, in the method of manufacturing a liquid crystal cell using the cell sealing device of the present invention, after injecting a liquid crystal material into the cell, a pair of substrates constituting the cell are evacuated while being pressurized and held,
The method further comprises the step of sealing the injection hole portion after the cell gap of the cell reaches a predetermined target distance.

[Operation] The cell sealing device according to the present invention includes one vacuum suction table for sealing the liquid crystal material after the liquid is injected from the injection hole of the cell in which a pair of substrates are connected via a sealing material, and the other. The substrate is sucked and held by the vacuum suction table, and the injection hole can be sealed with a sealing material while the cell is pressurized and held. By using this device, it is possible to produce a liquid crystal cell having a uniform cell gap as intended even if the liquid crystal material is in a medium-solid state before being injected into the cell.

A method of manufacturing a liquid crystal cell using the apparatus will be described. First, after injecting liquid crystal into a cell whose cross-sectional shape is a middle bevel shape, with the upper and lower surfaces thereof being pressure-held by a vacuum suction table, evacuating is started while the cell is pressure-held,
The cell is adsorbed to a predetermined vacuum degree X1 [mmHg]. Then, the first substrate and the second substrate of the cell are respectively adsorbed on the vacuum adsorption table, and the distortion of each substrate is pulled up toward the vacuum adsorption table where the respective substrates come into contact, and as a result, the cell gap becomes a predetermined uniform value. Approaching the target gap.

Next, a sealing material is applied to the liquid crystal injection hole, the degree of vacuum of the vacuum suction table is further raised to X2 [mmHg], and the sealing material is cured when the sealing material is slightly inserted into the cell. Then, the vacuum suction is released. At this time, the target liquid crystal cell having a predetermined uniform target gap can be formed. Then, the pressure holding of the vacuum suction table is released and the liquid crystal cell is taken out. The relationship between the vacuum degrees X1 and X2 is X1> X2. As described above, it becomes possible to hold the cells, which are manufactured to have a medium cross-sectional shape in cross section, in a predetermined uniform target cell gap and perform the sealing treatment.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION A cell sealing device according to an embodiment of the present invention and a method for manufacturing a liquid crystal cell using the sealing device will be described below with reference to FIGS. In the embodiment of the invention of the present specification, a glass substrate having a plate thickness of 0.5 mm was used, a cell gap of the cell was 4 μm to 6 μm, and a small cell whose outer dimension was about 10 mm diagonal was used. Further, a liquid crystal cell which does not have an internal spacer in the cell and holds the cell gap only by the spacer in the seal and the sealing material will be described below as an example.

FIG. 1 shows a front view of a cell sealing device according to an embodiment of the present invention. Further, FIG. 2 is an enlarged cross-sectional view taken along the line AA of FIG. 1 on a scale twice as large as that of FIG.
Hereinafter, the structure of the cell sealing device according to the embodiment of the present invention will be described with reference to FIGS. 1 and 2. In FIG. 1, the air bag 18 is filled with air and inflated to raise the pressure table 15, and the upper vacuum suction table 13 and the lower vacuum suction table 14 are used to make the cell 1
It is shown that 9 is pressurized and held.

The air bag 18 shown here is installed between the lower surface of the pressurizing table 15 and the upper surface of the lower part 12 of the main body, and air is sent into the air bag 18 to inflate it so that the pressurizing table 15 is pushed up vertically to form the cell 19 therein. The upper suction table 13 and the lower vacuum suction table 14 can hold pressure. Also,
The upper vacuum suction table 13 is fixed to the lower surface of the upper part 11 of the main body by screwing or adhesion, and the flatness of the vacuum suction surface of the upper vacuum suction table 13 is processed with high accuracy. Further, the lower vacuum suction table 14 is fixed to the upper surface of the pressure table 15 with screws or adhesives. The flatness of the vacuum suction surface of the lower vacuum suction table 14 was processed with high precision. Although not shown in the drawing, the upper vacuum suction table 13 and the lower vacuum suction table 14 are evacuated and the air is supplied to the airbag 18, respectively, through regulators to adjust the degree of vacuum or the pressure. Each has a possible configuration.

The upper body 11 is fixed in parallel with the lower body 12 by four cylinders 16 by screwing or gluing, and the pressure table 15 is arranged along the cylinder 16 between the upper body 11 and the lower body 12. Four guide bushes 17 are provided for smooth vertical movement.

Further, as shown in FIG. 2, the lower vacuum suction table 1
4 has a liquid crystal cell stopper 21 for positioning and installing the cell on the upper surface. Further, on the upper surface of the lower vacuum suction table 14, a dummy plate 20 functioning for height adjustment and pressure dispersion, and a dummy plate stopper 22 for positioning and installing the dummy plate 20 are provided.

The cell sealing device according to the embodiment of the present invention corresponds to the strip-shaped cell shown in FIG. Therefore, the cell sealing device has a horizontally long shape. However, in the cell sealing device according to the embodiment of the present invention, the same effect can be obtained for a single cell by using the dummy cell having a predetermined size.

Next, a cell sealing treatment method using the cell sealing device according to the embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 3 is an enlarged cross-sectional view of an essential part showing a state of pressurizing and holding the cell 19. FIG. 4 is an enlarged cross-sectional view of an essential part showing a state where the cell 19 is vacuum-held while being pressurized and held at a vacuum degree of X1 [mmHg]. Furthermore, FIG.
9 is an enlarged cross-sectional view of an essential part showing a state of performing vacuum suction at a vacuum degree of X2 [mmHg] while holding 9 under pressure.

First, according to the cell manufacturing method shown in the prior art, spacers are mixed in the sealing material to form cells. Then, as described above, the cell before the liquid crystal material is injected is in a solid state shown in FIG. 8B.

Next, as shown in FIG. 2, after the liquid crystal material is injected into the cell 19 having the cross section of the middle bezel shape, the middle bezel shape of the cell 19 is placed on the lower vacuum suction base 14 and the stopper 2 for the liquid crystal cell.
Use 1 to position and install. Similarly, the dummy plate 20 is positioned and installed on the lower vacuum suction table 14 using the dummy plate stopper 22. As the dummy plate 20, two glass substrates of the same size and kind as the glass substrate used for the cell 19 were used to adjust the height.

Next, air is slowly supplied to the air bag 18, the pressure plate 15 is gently raised, and the cell 19 and the dummy plate 20 are pressure-held. The applied pressure at this time is 0.1 kg
/ Cm ² is sufficient.

At this time, as shown in FIG. 3, the cross section of the cell 19 is still in the shape of a midbed. Further, the liquid crystal 25 is attached to the periphery of the liquid crystal injection hole 32 of the cell 19.

Next, the upper vacuum suction table 13 and the lower vacuum suction table 14 respectively have a predetermined vacuum degree X on both surfaces of the cell 19.
Vacuum adsorption is performed at 1 [mmHg]. At this time, as shown in FIG. 4, the first substrate 33 and the second substrate 34 of the cell 19 are formed.
Are the upper vacuum suction table 13 and the lower vacuum suction table 14, respectively.
And the inside of the cross section of the cell 19 is almost eliminated. Further, the liquid crystal 25 attached to the periphery of the liquid crystal injection hole 32 of the cell 19 is replenished in the cell as the substrate is deformed. In addition, in the cell sealing method in the embodiment, X1 = −50 when the atmospheric pressure is 0 [mmHg].
It was set to about 0 to -400 [mmHg].

In this state, the liquid crystal 25 adhering to the periphery of the liquid crystal injection hole 32 is wiped off, and as shown in FIG. 5, a sealing material 26 such as an ultraviolet curable resin is applied to the liquid crystal injection hole 32 by a dispenser or the like. To do.

Then, the degree of vacuum of vacuuming the cell 19 by the upper vacuum suction table 13 and the lower vacuum suction table 14 is further increased to X2 [mmHg]. Then cell 1
The cross-sectional shape of the cross section of 9 is eliminated, resulting in a predetermined uniform aiming gap.

In the cell sealing method according to this embodiment, X2 = -600 to -500 [mmHg].
It was about degree. At this time, an appropriate amount of the sealing material 26 applied to the liquid crystal injection hole 32 enters the inside of the cell 19. When the sealing material 26 is cured at this timing, the liquid crystal 25 is completely sealed in the cell 19.

After the sealing material 26 is cured, the vacuum suction of the upper vacuum suction table 13 and the lower vacuum suction table 14 in FIG. 1 is released. Then, the air pressure of the airbag 18 is gradually released to gently lower the pressurizing table 15 and take out the liquid crystal cell. In the liquid crystal cell taken out at this time, the distortion of the substrate is corrected by the positive pressure of the liquid crystal material inside the liquid crystal cell, and the predetermined uniform cell gap is maintained.

Further, according to the cell sealing device and the method for manufacturing a liquid crystal cell using the sealing device in the embodiment,
The in-plane unevenness of the cell gap of the cell 19 in the embodiment of the present invention could be suppressed within ± 0.025 μm.

[0040]

As is apparent from the above description, the cell sealing device of the present invention and the method for manufacturing a liquid crystal cell using the sealing device produced the cross-sectional shape before injection of the liquid crystal to be a medium bevel shape. The cells can be accurately held in a predetermined uniform target cell gap and subjected to the sealing treatment. As a result, it becomes possible to manufacture a high-quality liquid crystal cell with a uniform cell gap and very little in-plane unevenness.

Needless to say, the technique can be applied to the production of a liquid crystal cell using cells in which spacers are scattered in an optically effective region by using the cell sealing device of the present invention.

[Brief description of drawings]

FIG. 1 is a front view showing a cell sealing device according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a cell sealing device according to an embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view of an essential part showing a state of pressurizing and holding a cell for explaining a method for manufacturing a liquid crystal cell according to an embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view of an essential part showing a state of vacuum suction at a vacuum degree X1 while holding a cell under pressure, for explaining a method for manufacturing a liquid crystal cell according to an embodiment of the present invention.

FIG. 5 is an enlarged cross-sectional view of an essential part showing a state of vacuum adsorption at a vacuum degree X2 while holding the cell under pressure, for explaining a method for manufacturing a liquid crystal cell according to an embodiment of the present invention.

6A and 6B are a plan view and a cross-sectional view showing a large number of cells formed on a large-sized substrate in a conventional manufacturing method.

FIG. 7 is a plan view showing a strip-shaped cell and a single cell in a conventional manufacturing method.

8A and 8B are a schematic plan view and a cross-sectional view showing a cell having a cross-section having a middle shape in the related art.

[Explanation of symbols]

11 Upper body 12 Lower body 13 Upper vacuum suction table 14 Lower vacuum suction table 15 Pressure table 16 cylinders 17 Guide bush 18 airbags 19 cells 20 dummy board 21 Liquid crystal cell stopper 22 Stopper for dummy plate 23 Seal material 24 Spacer in seal 25 liquid crystal 26 Sealing material 31 Optically effective area 32 Liquid crystal injection hole 33 First substrate 34 Second substrate

Claims (5)

[Claims] 1. A cell sealing device for sealing a liquid crystal material after injecting the liquid crystal material through an injection hole of a cell in which a pair of substrates are connected via a sealing material, wherein a vacuum suction table on one side and a vacuum on the other side. A cell sealing device, characterized in that the injection hole can be sealed with a sealing material in a state where each of the pair of substrates of the cell is sucked by a suction table. 2. The cell sealing device according to claim 1, wherein the cell sealing operation is performed while maintaining the cell under pressure. 3. The cell sealing device according to claim 1, wherein one of the vacuum suction tables is fixed to the device main body, and the other is operated by an air bag to perform the pressurization. . 4. The other vacuum suction table is arranged on a pressure table,
4. The cell sealing device according to claim 3, wherein a guide bush that operates vertically along the cylinder enables the other vacuum suction table together with the pressurizing table to operate up and down. 5. A method of manufacturing a liquid crystal cell using the cell sealing device according to claim 1, wherein a pair of substrates constituting the cell is added after the liquid crystal material is injected into the cell. A method for manufacturing a liquid crystal cell, which comprises a step of evacuating while maintaining pressure and sealing the injection hole portion after the cell gap of the cell reaches a predetermined target interval.