JP3399837B2 - Liquid crystal cell manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal cell used in a liquid crystal display device, and more particularly, to a liquid crystal cell in which the time for injecting a liquid crystal material into the cell is shortened and the cell thickness is uniform. The present invention relates to a manufacturing method.

[0002]

2. Description of the Related Art A liquid crystal cell 21 before a liquid crystal material is injected.
Is shown in FIGS. 6 (a) and 6 (b). The liquid crystal cell 21 has two rectangular transparent substrates 22 and 23 made of glass or the like. The peripheral portions of these two transparent substrates 22 and 23 are bonded together by a sealing material 24, and these two transparent substrates 22 and 23 and the sealing material 24 make the space portion 2 with a very small thickness.
6 is formed. A gap member 27 for holding the thickness of the space 26 is sandwiched in the space 26. Further, the sealing material 24 is cut off at one side of the liquid crystal cell 21 to form an opening. This opening is the liquid crystal injection port 25, and the liquid crystal material is injected into the space 26 from here.

As a method of injecting the liquid crystal material into the space 26, there is a method described below.

The most general method will be described with reference to FIG. First, the liquid crystal container 32 containing the liquid crystal material 31 is placed in the vacuum chamber 30, and the liquid crystal cell 21 is set above the liquid crystal container 32 so that the liquid crystal inlet 25 faces the liquid crystal container 32. At this time, the liquid crystal injection port 25 of the liquid crystal cell 21 is arranged so as not to contact the liquid crystal material 31. Next, the inside of the vacuum chamber 30 is evacuated to reduce the pressure, and the inside of the liquid crystal cell 21 (the space 26 in FIG. 6) is exhausted. When a predetermined pressure is reached, the liquid crystal inlet 25 and the liquid crystal material 31 are brought into contact with each other, and then the vacuum chamber 30
The inside is returned to atmospheric pressure.

As a result, the liquid crystal material 31 is injected into the liquid crystal cell 21. A method of further developing such an injection method and eliminating waste of the liquid crystal material 31 is disclosed in JP-A-9-5.
4327, etc.

In order to shorten the time required for injecting the liquid crystal, the inside of the liquid crystal cell is evacuated using the vacuum chamber 30 as described above, and then the liquid crystal injection port 25 is applied while the vacuum chamber 30 is depressurized. There is also a method of connecting a connector connected to the liquid crystal pressure supply device and injecting the liquid crystal material 31 while applying pressure.

[0007]

However, among the conventional injection methods described above, the vacuum chamber 30 shown in FIG. 7 is used.
In the injection method that uses the pressure difference between the inside and the outside of the cell by returning the inside pressure to the atmospheric pressure, the area in contact with the liquid crystal material 31 is set to be equal to or larger than the width of the liquid crystal injection port 25 in order to prevent bubbles from being mixed into the space 26. It is indispensable, and since it returns to atmospheric pressure and injects, adjustment of injection pressure is difficult.

As a result, the problem that the gap material 27 near the liquid crystal injection port 25 moves by the force of the liquid crystal material 31 at the time of injection, the problem of the liquid crystal injection flow trace, and the injection amount near the liquid crystal injection port 25 increase, There is a problem of uneven cell thickness in that the vicinity of the liquid crystal injection port 25 swells after injection, compared to other portions. All of these problems cause display defects.

In addition, with the recent increase in the cell size, it takes a considerable time to inject the liquid crystal. Therefore, it is strongly desired to shorten the time for injecting the liquid crystal.
Although this is dealt with by increasing the width of No. 5, this method tends to further increase the problems such as the movement of the gap member 27 described above.

On the other hand, in the latter method using the pressurized liquid crystal supply device, the injection pressure can be adjusted to some extent by adjusting the pressure of the pressurizing means. Therefore, as compared with the method of returning to the atmospheric pressure and injecting, the problems caused by the above problems caused by the adjustment of the injection pressure can be reduced. However, even with this method, it is difficult to accurately adjust the injection pressure, and in particular, cell thickness unevenness swelling in the vicinity of the liquid crystal injection port 25 is conspicuous.

The present invention has been made in view of the above-mentioned problems, and it is possible to prevent excessive liquid crystal injection by adjusting the injection pressure of the liquid crystal material with high accuracy, and to achieve both shortening of the injection time and reduction of display defects. It is intended to provide a method for manufacturing a cell.

[0012]

In order to solve the above-mentioned problems, the method of manufacturing a liquid crystal cell according to claim 1 of the present invention is
A method of manufacturing a liquid crystal cell, which includes a liquid crystal injection step of injecting a liquid crystal material from an opening where the sealing material is removed between a pair of substrates which are bonded to each other with a sealing material disposed at a peripheral portion with a predetermined gap. In, in the liquid crystal injection, the area of the opening that comes into contact with the liquid crystal material is adjusted to be smaller than the actual opening area, and the portion of the opening that is not in contact with the liquid crystal material is sealed, and initially with a large pressure, On the way
They are characterized by injecting while gradually pressurizing the liquid crystal material as a pressure smaller than that .

In order to achieve the above-mentioned object, the inventors of the present invention have made earnest studies on a method of injecting a liquid crystal material, and as a result, have made an adjustment to make the area in contact with the liquid crystal material smaller than the actual area of the liquid crystal injection port. It has been found that the injection pressure can be adjusted more accurately by adjusting the injection pressure while performing the injection. The portion where the liquid crystal material was not in contact was sealed so that air bubbles and the like did not enter. Pressurization of the liquid crystal material is a large pressure at the beginning, and from the middle
Has less pressure than that.

Therefore, with the above configuration, the injection pressure of the liquid crystal material is accurately adjusted to cause problems such as movement of the gap material for holding the substrates, generation of liquid crystal injection flow traces, and bulging in the vicinity of the liquid crystal injection port. As a result, the injection time can be shortened and the display defects can be reduced.

The method of manufacturing a liquid crystal cell according to a second aspect of the present invention is the method according to the first aspect, wherein the area of the opening which is in contact with the liquid crystal material is 1/4 to 3 / of the actual area of the opening.
It is characterized by adjusting within the range of 4.

By making the area of the opening which is in contact with the liquid crystal material within the range of 1/4 to 3/4 of the actual area of the opening, the injection pressure can be easily controlled and the unevenness of the cell thickness can be reduced. This facilitates cell thickness control.

The method for producing a liquid crystal cell according to claim 3 of the present invention is the method according to claim 1, wherein the injection pressure of the liquid crystal material is in the range of 0.01 to ² kgf / cm ² in two or more steps. It is characterized by injecting.

The injection pressure of the liquid crystal material is 0.01 to 2 kgf.
Within the range of / cm ² , the gap material is unlikely to move. By injecting in two or more stages within this range, the injection time can be shortened as compared with the case of injecting at a constant injection pressure.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS.

First, the liquid crystal cell 1 before the liquid crystal material used in this embodiment is injected will be described with reference to FIGS.

The liquid crystal cell 1 has two rectangular substrates 2 and 3 made of a transparent material such as glass. The outer peripheries of these two substrates 2 and 3 are adhered to each other with a sealing material 4, and the two substrates 2 and 3 and the sealing material 4 form a space 6 having a very small thickness. A gap member 7 for holding the thickness of the space 6 is sandwiched in the space 6. Then, the sealing material 4 is cut off at two opposing sides of the liquid crystal cell 1 to form three openings.

The two openings on one side are exhaust ports 8a and 8b for exhausting the air in the space 6, respectively. The opening formed on the side facing the exhaust ports 8a and 8b is the liquid crystal injection port 5 for injecting the liquid crystal material into the space 6.

The structure of a liquid crystal injection system for injecting a liquid crystal material into such a liquid crystal cell 1 is shown in FIG.

Suction connectors 11 and 11 are connected to the exhaust ports 8a and 8b of the liquid crystal cell 1, respectively. One end of a vacuum suction pipe 12 is connected to the suction connectors 11 and 11, and the other end of the vacuum suction pipe 12 is connected to a vacuum pump 13 via an opening / closing valve 14. This allows
In the state where the opening / closing valve 14 is opened, the air inside the liquid crystal cell 1 (the space 6 shown in FIG. 2) is discharged through the exhaust port 8a.
-Exhaust through 8b.

On the other hand, an injection connector 15 is connected to the liquid crystal injection port 5 of the liquid crystal cell 1. The injection connector 15 has
One end of the liquid crystal supply pipe 16 is connected, and the other end of the liquid crystal supply pipe 16 is connected to the pressurizing liquid crystal supply device 17 by the opening / closing valve 1.
8 are connected. The pressurized liquid crystal supply device 17
Is to pressurize the liquid crystal material 9 and send it out to the liquid crystal supply pipe 16, which is provided with a pressurizing means so that the supply pressure of the liquid crystal material 9 can be adjusted. As a result, the opening / closing valve 18
Is opened, the space 6 of the liquid crystal cell 1 is
Then, the liquid crystal material 9 is injected through the liquid crystal injection port 5.

As shown in FIG. 4, in the injection connector 15, the portion where the liquid crystal injection port 5 is formed in the liquid crystal cell 1 is sandwiched by sealing portions 15a and 15a 'made of a deformable material such as rubber. It is a composition. The liquid crystal supply pipe 16 is passed through the sealing portion 15a, and the other sealing portion 15a 'is pressed against the sealing portion 15a by the clamping force of the clip members 15b and 15b', so that the liquid crystal injection port 5 is completely removed. It is supposed to be sealed. The configuration up to this point has substantially the same configuration except that the suction connector 11 also has the vacuum suction tube 12 inserted therein instead of the liquid crystal supply tube 16.

By the way, as described above, by injecting the liquid crystal material 9 under pressure, the time required for injecting the liquid crystal can be shortened. However, even in that case, it is difficult to control the pressure during the injection, and the gap material 7 near the liquid crystal injection port 5 is difficult.
Moves due to the momentum of the liquid crystal material 9 at the time of injection, traces of liquid crystal injection flow occur, or the injection amount in the vicinity of the liquid crystal injection port 5 increases, and after injection, the vicinity of the liquid crystal injection port 5 is larger than other parts. There is a problem that the cells bulge and uneven cell thickness occurs.

Therefore, in the present embodiment, the injection connector 15 in the liquid crystal injection system has an area smaller than the area of the liquid crystal injection port 5 as shown in FIG.
The contact area between the liquid crystal injection port 5 and the liquid crystal material 9, that is, the contact width is adjusted so that the liquid crystal can be injected. Specifically, the width of the tip nozzle of the liquid crystal supply tube 16 shown in FIG. 4 can be adjusted. At this time,
Of course, the region of the liquid crystal injection port 5 outside the tip nozzle is sealed by the sealing portion 15a so that air is not mixed therein.

By using such a liquid crystal injection system, the liquid crystal material 9 is injected under pressure through the liquid crystal injection port 5 while exhausting the inside of the liquid crystal cell 1 through the exhaust ports 8a and 8b, so that the injection pressure can be adjusted accurately. It is possible to prevent the excessive injection of the liquid crystal material 9, the movement of the gap material 7, the generation of the liquid crystal injection flow trace, etc. while shortening the time required for the liquid crystal injection.

At this time, the width of the tip nozzle with respect to the width (area) of the liquid crystal injection port 5 (the area where the liquid crystal material 9 actually contacts) is within the range of 1/4 to 3/4, and the injection pressure is It has been confirmed that the cell thickness becomes easy to control, and as a result, the cell thickness can be effectively controlled.

At this time, the liquid crystal injection pressure is set to 0.01.
It is desirable to inject under pressure in the range of ² kgf / cm ² in two or more stages. It has been confirmed that the gap material 7 does not move within the above range, and the injection time can be shortened and good display quality and cell thickness control can be facilitated without causing a significant delay in the injection time.

Here, the case where the liquid crystal material 9 is pressure-injected from the liquid crystal injection port 5 while exhausting from the exhaust ports 8a and 8b is illustrated, but the exhaust ports 8a and 8b are not always necessary, and are conventionally used. As described above, also in the configuration in which the inside of the liquid crystal cell 1 is evacuated by using the vacuum chamber and then the liquid crystal material 9 is pressure-injected through the liquid crystal inlet,
By using 5 to reduce the area where the liquid crystal material 9 contacts the liquid crystal injection port 5 and perform pressure injection, the same action and effect can be obtained.

[0033]

EXAMPLE FIG. 3 described in the above embodiment will now be described.
The present invention will be further described by way of examples employing the liquid crystal injection system of FIG. Of course, the invention is not limited to the embodiments shown here.

Example 1 The width of the liquid crystal injection port 5 is 20 mm
The liquid crystal injection port 5 and the exhaust ports 8a and 8b of the 14-inch class liquid crystal cell 1 are attached with the injection connector 15 and the suction connector 11 and 11, and the inside of the liquid crystal cell 1 is evacuated to a reduced pressure, and then the exhaust ports 8a and 8b. The liquid crystal material 9 was supplied from the liquid crystal injection port 5 side while sucking at a constant pressure from. Further, at this time, as shown in FIG. 5A, the pressure was increased at the beginning and was made smaller than that in the middle, so that the gap member 7 was gradually pressured so as not to move.

At this time, as shown in Table 1, the liquid crystal injection port 5
The width of the tip nozzle of the injection connector 15 was adjusted so that the contact width of the liquid crystal material 9 was 5 mm. Also,
The portion where the liquid crystal material 9 is not in contact is sealed so that air bubbles and the like do not enter.

As a result, after 100 minutes, the liquid crystal material 9 could be filled in the space of the liquid crystal cell. In addition, the gap material 7 did not move and good display quality was obtained. In addition, the cell thickness variation σ of 30 points in the plane was also good.

However, the injection time was slower than the conventional method using the vacuum chamber 30 shown in FIG.

Example 2 When the contact width with the liquid crystal material 9 was set to 10 mm by the same injection method as in Example 1, 7
The injection of the liquid crystal material 9 was completed in 0 minutes. Also at this time,
As shown in FIG. 5 (b), the injection was performed while gradually applying pressure so that the gap material 7 did not move.

As a result, the gap material 7 did not move and the cell thickness variation was better than that of the conventional injection method shown in FIG. That is, by making the contact width of the liquid crystal material 9 half the width of the liquid crystal injection port 5 of the liquid crystal cell 1, the injection pressure can be controlled easily, and as a result, the injection time can be shortened and the cell thickness can be controlled. It has become possible to find points with good display quality.

[Example 3] When the contact width with the liquid crystal material 9 was set to 15 mm by the same injection method as in Example 1, 5
The injection of the liquid crystal material 9 was completed in 5 minutes. Also at this time, as shown in FIG. 5C, the injection was performed while gradually applying pressure so that the gap material 7 did not move.

As a result, the injection time could be shortened more than in Example 2, but the liquid crystal injection port 5 and its vicinity were slightly overfilled with liquid crystal. However, no liquid crystal injection flow trace was generated, and there was no problem in display quality.

[Comparative Example 1] The width of contact with the liquid crystal material 9 was set to 20 mm by the same injection method as in Example 1, and the width of the liquid crystal injection port 5 of the liquid crystal cell 1 and the contact portion of the liquid crystal material 9 were changed as in the conventional case. When the liquid crystal material 9 was injected under pressure, as shown in FIG. 5D, injection of the liquid crystal material 9 was completed in 40 minutes. The injection time was quite short. However, the gap material 7 was moved, and a bulge near the liquid crystal injection port 5 was also seen. In other words, it is difficult to control the injection pressure due to the large amount of liquid crystal supplied. As a result, the cell thickness variation σ also worsened.

Comparative Example 2 Further, as a result of conducting an experiment by the method using the conventional vacuum chamber 30 shown in FIG. 7, the injection of the liquid crystal material 31 was completed in 75 minutes. Of course, the width of the liquid crystal injection port 25 and the liquid crystal contact portion are 20 m or more, so that the gap material 27 is moved. Further, the variation in cell thickness was the worst, and a trace of liquid crystal injection and a bulge in the vicinity of the liquid crystal injection port 25 also occurred.

[0044]

[Table 1]

[0045]

As described above, the method of manufacturing a liquid crystal cell according to the first aspect of the present invention is characterized in that, between the pair of substrates bonded together with a predetermined gap by the sealing material arranged at the periphery,
In a method for manufacturing a liquid crystal cell, which includes a liquid crystal injection step of injecting a liquid crystal material through an opening from which the sealing material is removed, the area of the opening that comes into contact with the liquid crystal material during liquid crystal injection is adjusted to be smaller than the actual opening area. Te does not contact the liquid crystal material in the opening portion is sealed, and the first
Is a large pressure, and from the middle is a smaller pressure
Then, the liquid crystal material is injected while being pressurized stepwise .

Thus, the injection pressure of the liquid crystal material is accurately adjusted to solve the problems such as the movement of the gap material holding the substrates, the generation of the liquid crystal injection flow trace, and the bulge in the vicinity of the liquid crystal injection port. Both injection time and display defects can be reduced.

As a result, it is possible to produce a liquid crystal cell having excellent display quality in a shorter time, and to provide a liquid crystal display device having excellent display quality at a lower cost.

According to a second aspect of the present invention, in the method for producing a liquid crystal cell according to the first aspect, the area of the opening which is in contact with the liquid crystal material is 1/4 to 3 / of the actual area of the opening.
It is characterized by adjusting within the range of 4.

As a result, the injection pressure can be controlled more easily and the cell thickness can be controlled more easily.

As a result, the above-mentioned effects can be obtained.
The manufacturing method of the liquid crystal cell described in can be more reliably carried out,
There is an effect that the above effect can be reliably obtained.

The method for producing a liquid crystal cell according to claim 3 of the present invention is the method according to claim 1, wherein the injection pressure of the liquid crystal material is in the range of 0.01 to ² kgf / cm ² in two or more steps. It is characterized by injecting.

As a result, the injection time can be shortened while easily controlling the cell thickness as compared with the case where the injection is performed at a constant injection pressure.

As a result, the above-mentioned effects can be obtained.
The liquid crystal cell manufacturing method described in (1) above can be more effectively carried out, and a liquid crystal display device having further excellent display quality can be provided at low cost.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention and is an explanatory diagram showing a contact width of a liquid crystal material with respect to a width of a liquid crystal injection port when a liquid crystal material is injected into a liquid crystal cell.

2A is a plan view of a liquid crystal cell into which a liquid crystal material is injected, and FIG. 2B is a sectional view thereof.

FIG. 3 is a schematic diagram showing a configuration of a liquid crystal injection system for injecting a liquid crystal material into a liquid crystal cell.

FIG. 4 is a cross-sectional view showing a configuration of an injection connector in the liquid crystal injection system.

5 (a) to (e) are graphs showing injection pressures of liquid crystal materials in Examples and Comparative Examples of the present invention.

6A and 6B show a conventional technique, in which FIG. 6A is a plan view of a liquid crystal cell into which a liquid crystal material is injected, and FIG. 6B is a sectional view thereof.

FIG. 7 is an explanatory diagram showing a liquid crystal injection method for injecting a liquid crystal material into a conventional liquid crystal cell.

[Explanation of symbols]

1 Liquid crystal cell 2.3 Transparent substrate (substrate) 4 Seal material 5 Liquid crystal inlet (opening) 6 space section 7 Gap material 8a / 8b exhaust port 11 Suction connector 15 injection connector 16 Liquid crystal supply tube 17 Pressurized liquid crystal supply device

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-7-199201 (JP, A) JP-A-9-203906 (JP, A) JP-A-5-313110 (JP, A) JP-A-6- 67136 (JP, A) JP 10-10502 (JP, A) JP 10-104642 (JP, A) JP 10-142615 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02F 1/1341 G02F 1/13 101 G02F 1/1339

Claims (3)

(57) [Claims] 1. A liquid crystal injecting step of injecting a liquid crystal material through an opening from which the sealing material is removed, between a pair of substrates which are bonded to each other with a sealing material disposed at a peripheral portion thereof with a predetermined gap therebetween. In the method for manufacturing a liquid crystal cell, the area of the opening that comes into contact with the liquid crystal material during liquid crystal injection is adjusted to be smaller than the actual opening area, and the portion of the opening that is not in contact with the liquid crystal material is sealed, and
Large pressure at first, less pressure halfway
As a method for manufacturing a liquid crystal cell, the liquid crystal material is injected while being pressurized stepwise . 2. The production of a liquid crystal cell according to claim 1, wherein the area of the opening which is in contact with the liquid crystal material is adjusted within a range of 1/4 to 3/4 of the actual area of the opening. Method. 3. The injection pressure of the liquid crystal material is 0.01 to 2 kgf.
The method for producing a liquid crystal cell according to claim 1, wherein the injection is performed in two or more steps within a range of / cm ² .