JPH1010545A - Manufacture of liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the manufacturing method of a liquid crystal display device making possible performing defoam processing of a liquid crystal in a short time to a sufficient extent and preventing air from re-mixing with the defoam processed liquid crystal. SOLUTION: A flat circular recessed part 10c is formed on a central part inside of a bottom surface part of a liquid crystal tank 10, and a stirrer 12 housing a magnet in its inside is housed rotatably in the recessed part 10c. An electromagnetic coil 13 is incorporated downward the recessed part 10c, and a variation magnetic field is generated by energizing through the electromagnetic coil 13, and the stirrer 12 is constituted so as to be rotated in the recessed part 10c by the variation magnetic field. An ultrasonic vibrator transducer 14 incorporating a circularly formed dielectric element is attached to the outer peripheral surface of the lower part of the liquid crystal tank 10, and is constituted so as to apply vibration to the liquid crystal in the tank.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display, and more particularly, to a method for processing liquid crystal injected into a liquid crystal panel.

[0002]

2. Description of the Related Art Conventionally, in a process of manufacturing a liquid crystal display device, two substrates are bonded at a predetermined interval via a sealing material, and a liquid crystal panel having a liquid crystal enclosing region formed by the sealing material is formed. There are a forming step and a step of injecting liquid crystal into the liquid crystal panel.

In the liquid crystal injecting step, the liquid crystal is subjected to a defoaming process in order to remove air mixed in the liquid crystal to be injected, and it is necessary to prevent bubbles from being generated in the panel after the liquid crystal is injected into the panel. Preventing.

[0004] This defoaming treatment is usually carried out by evacuating the inside of the tank containing the liquid crystal and leaving it to stand for about 10 hours. The liquid crystal subjected to the defoaming treatment is stored in a vacuum state, and when exposed to the air after the defoaming treatment, the liquid crystal is subjected to the defoaming treatment again.

[0005]

However, the above-mentioned conventional defoaming treatment requires a very long time, and furthermore, it is necessary to maintain a vacuum state during storage, which makes it difficult to control the manufacturing process. There is a problem.

In the conventional defoaming process, the degree of defoaming is not always sufficient.
Leaving the liquid crystal panel at a low temperature or applying vibration to the liquid crystal panel causes a problem that bubbles are generated in the liquid crystal layer.

Further, in the above-mentioned conventional defoaming treatment,
Since the liquid crystal is transferred from the tank to the injection tank etc. after the defoaming treatment, air may be mixed in at the time of this transfer, and in order to avoid this, the liquid crystal must be transferred in a vacuum. There are points.

Accordingly, the present invention has been made to solve the above problems, and an object thereof is to provide a technique capable of performing a defoaming treatment of liquid crystal in a short time and to a sufficient extent. An object of the present invention is to provide a manufacturing method in which air is not mixed again into the liquid crystal subjected to the defoaming treatment.

[0009]

In order to solve the above-mentioned problems, the present invention provides a method of manufacturing a liquid crystal display device by injecting liquid crystal into a liquid crystal panel. A defoaming treatment is performed while stirring in a vacuum, and then the liquid crystal is injected into the liquid crystal panel.

[0010] According to this means, by performing the defoaming treatment while stirring in a vacuum, the liquid crystal flows by stirring, so that the air mixed in the liquid crystal is easily separated,
Since bubbles generated by separation are also easily released from the liquid surface, uniform processing can be performed quickly and reliably. In addition, it is desirable that the stirring is performed in the inner part of the liquid crystal container in order to enhance the stirring effect and promote the discharge of bubbles.

Here, in the defoaming process, it is preferable to perform the process while applying vibration to the liquid crystal by a vibration applying means.

According to this means, the separation of air and the discharge of air bubbles can be promoted by applying vibration to the liquid crystal. In particular, the air bubbles which are likely to remain in the inner part of the liquid crystal accommodating portion are efficiently removed by vibration. Can be eliminated. Note that the vibration is desirably high-frequency ultrasonic vibration, and the vibration application position is desirably set at the back of the liquid crystal housing.

In the defoaming treatment, it is preferable to perform heating so that the essential components contained in the liquid crystal are not substantially volatilized.

According to this means, by heating the liquid crystal so as not to affect the liquid crystal, it is possible to reduce the viscosity of the liquid crystal while suppressing the volatilization of the effective component of the liquid crystal.
The defoaming process is promoted, and the efficiency of the process can be improved.

Further, the liquid crystal is accommodated in a liquid crystal supply container provided with liquid crystal extruding means configured to supply the liquid crystal to the liquid crystal panel, and the liquid crystal supply container is evacuated. Preferably, the defoaming treatment is performed.

According to this means, after performing the defoaming treatment in the liquid crystal supply container, the liquid crystal can be supplied as it is, so that the processed liquid crystal can be easily used without being exposed again to the atmosphere. Can be.

Here, it is preferable that vibration applying means is provided around the liquid crystal supply container, and the defoaming treatment is performed while applying vibration to the liquid crystal by the vibration applying means.

The vibration applying means in the above means utilizes heat generated when the vibration is generated,
It is desirable that the liquid crystal is also used as a heating means for heating to such an extent that essential components contained in the liquid crystal are not substantially volatilized.

According to this means, without providing a separate heating means, it is possible to lower the viscosity of the liquid crystal to promote the defoaming treatment, thereby improving the efficiency of the treatment.

[0020]

Next, an embodiment according to the present invention will be described with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is an explanatory view showing a state in which a defoaming process is performed for explaining a first embodiment of a method of manufacturing a liquid crystal display device according to the present invention. The liquid crystal tank 10 for containing the liquid crystal is formed of a fluororesin. An exhaust port 10a for connecting to a vacuum device is provided at the upper part of the liquid crystal tank 10, and an exhaust port 10 for discharging the processed liquid crystal is provided at the bottom of the liquid crystal tank 10.
b is provided, and a discharge valve 11 is attached to the discharge port 10b.

A flat circular recess 10c is formed inside the center of the bottom of the liquid crystal tank 10, and a stirrer (stirrer) 1 containing a magnet therein is formed in the recess 10c.
2 are rotatably accommodated. An electromagnetic coil 13 is provided below the concave portion 10c.
The stirrer 12 is configured to rotate in the concave portion 10c due to the fluctuating magnetic field generated by energizing the stirrer.

On the outer peripheral surface at the lower part of the liquid crystal tank 10, an ultrasonic vibrator 14 having a built-in annular piezoelectric element is provided.
Is attached. The ultrasonic vibrator 14 has ring-shaped silver electrodes attached to the upper and lower sides of an annular piezoelectric body. The generated vibration is in a frequency band of 100 to 150 kHz.

In this embodiment, the air is exhausted from the exhaust port 10a and the pressure is reduced to about 0.05 torr or less (hereinafter referred to as "vacuum state").
That. ), The electromagnetic coil 13 is energized and the stirrer 1
2 is rotated to perform a defoaming process while stirring the liquid crystal.

In the conventional defoaming process, defoaming particularly near the bottom surface of the liquid crystal tank 10 tends to be incomplete, and therefore, it has been necessary to perform the process for a long time. Stirring by the stirrer 12 has the effect of stirring the liquid crystal near the bottom surface to promote the separation of air, and the effect of rapidly moving generated bubbles toward the liquid surface. Moreover, the liquid crystal in the liquid crystal tank 10 convects by this stirring, and the liquid crystal circulates up and down.
The liquid crystal can be uniformly and sufficiently defoamed.

The shape of the stirrer 12 is shown in FIG.
Various shapes can be provided as shown in FIGS. FIG. 2A shows a stirrer 12 arranged inside a concave portion 10c having a circular planar shape and having a contour of a cross-sectional shape formed in an uneven shape, and includes four blade portions.

On the other hand, the stirrer 12 'shown in FIG.
Has a circular cross-sectional shape that fits substantially inside the concave portion 10c, but is formed so as to be stirred by the uneven shape formed on the surface thereof. The projections and recesses 12′a provided with ribs extending in four directions from the center portion.
And a concave portion 12'b formed between the ribs of the convex portion 12'a
And is formed by. According to the stirrer 12 'shown in FIG. 2B, the amount of liquid crystal accommodated in the concave portion 10c which cannot be taken out of the tank can be reduced, so that waste of liquid crystal as expensive as precious metal can be prevented.

In this embodiment, since the ultrasonic vibration is applied from the outside of the liquid crystal tank 10, the separation between the liquid crystal and the air is promoted, the bubbles are easily generated, and the generated bubbles are caused by the applied vibration. The liquid is quickly caused to reach the liquid surface and is discharged. In this case, in order to more efficiently perform the separation of the air and the movement of the bubbles, the defoaming tends to be incomplete near the bottom surface of the liquid crystal tank 10 as described above.
Preferably, the vibration is applied from the lower part of the outer peripheral surface of the liquid crystal tank 10.

When the defoaming process is performed in the liquid crystal tank 10, the process can be completed in about 10 minutes, which has conventionally required a processing time of at least about 10 hours. The generation rate of bubbles after injecting the liquid crystal into the panel was reduced.

In the defoaming treatment, the viscosity of the liquid crystal greatly affects the defoaming efficiency. If the viscosity of the liquid crystal is high, the mixed air becomes difficult to separate as bubbles, and it is also difficult to exhaust the bubbles themselves from the liquid crystal. The viscosity of the liquid crystal greatly changes depending on the temperature of the liquid crystal. For example, in a general liquid crystal, the viscosity at room temperature (室温 20 ° C.) is 40 to 60 ° C.
When heated to ° C, the viscosity becomes about 1/4 to 1/10.

Therefore, by heating the liquid crystal moderately (about 40 to 60 ° C.) in the defoaming process, the processing time can be further shortened and the defoaming process can be more complete. If the temperature of the liquid crystal is raised to the above temperature (about 40 to 60 ° C., which depends on the components of the liquid crystal), the volatile effective components contained in the liquid crystal may be volatilized, which may cause deterioration of the liquid crystal characteristics. Tight temperature control is required.

In the present embodiment, a heater can be used to heat the liquid crystal. However, the ultrasonic vibrator 14 may be configured to generate heat and heat the liquid crystal in the liquid crystal tank 10. it can. Ultrasonic transducer 1
The adjustment of the calorific value of 4 can be made by designing the power consumption and the structure of the ultrasonic transducer.

(Second Embodiment) FIG. 3 is an explanatory view showing a state in which a defoaming process is performed in a second embodiment of the method of manufacturing a liquid crystal display device according to the present invention. In this embodiment, liquid crystal is dropped in a liquid crystal injection port (opening of a liquid crystal sealing area formed by a sealing material) of a liquid crystal panel (not shown) in a vacuum, and the liquid crystal injection port is closed by the dropped liquid crystal. Thereafter, a defoaming method suitable for injecting liquid crystal into the liquid crystal panel based on a pressure difference between the inside and outside caused by releasing the surroundings to atmospheric pressure is adopted.

The cylinder 20 is a cylindrical body made of fluororesin, and a piston body 30 as a liquid crystal pushing means having a piston part 31 and an operation part 32 is inserted through an opening 21. A closing member 24 is mounted on the opposite side of the opening 21, and a recess 24 a is formed on the inner surface side. A stirrer 25 similar to that of the first embodiment is rotatably housed in the concave portion 24a, and a closing member 24 located thereunder.
An electromagnetic coil 26 is built therein.

The closing member 24 is provided with a small-diameter outlet 27 communicating with the inside, and a supply tube 28 is attached to the outlet 27.

On the opening 21 side of the cylinder 20, there is provided an exhaust passage 22 extending in the operating direction of the piston body 30 and communicating with the inside of the cylinder 20 at a predetermined position.

An annular ultrasonic vibrator 29 similar to that of the first embodiment is mounted on the outer peripheral surface of the cylinder 20 near the closing member 24.

A liquid crystal is put in the cylinder 20, and the liquid crystal is accommodated in a vacuum chamber, and the inside of the chamber is evacuated. Next, the electromagnetic coil is energized to rotate the stirrer 25 and operate the ultrasonic vibrator 29 to apply vibration. In this manner, the defoaming process substantially similar to that of the first embodiment is performed. After the defoaming process is completed, the piston body 31 is inserted to lower the piston portion 31, and the sealing ring 33 attached to the outer periphery of the piston portion 31 is positioned below the opening of the exhaust passage 22 in the cylinder 20. Let it. In addition, the distal end of the supply tube 28 is also closed. As a result, since the inside of the cylinder 20 is sealed, the cylinder 20 can be taken out of the vacuum chamber.

Thereafter, the cylinder 20 is set at a predetermined position, the operating section 32 of the piston body 30 is connected to a driving section of a supply control device (not shown), and the supply tube 28 is mounted on a drip head provided with a drip nozzle. Thus, a liquid crystal injection step can be performed.

According to this embodiment, after the defoaming process is performed inside the cylinder 20, the liquid crystal can be supplied from the cylinder 20 in the liquid crystal injection step as it is.
The liquid crystal subjected to the defoaming process can be easily injected into the liquid crystal panel without releasing the vacuum state.

In this embodiment, the stirrer 25 is
4a, the upper surface of the stirrer 25 and the closing member 24
Is substantially the same height as the inner surface of the closing member 24, so that the piston portion 31 can be pushed close to the inner surface of the closing member 24, so that there is an effect that the liquid crystal is expensive and the processed liquid crystal is hardly wasted. This stirrer 25 is shown in FIG.
If the structure is the same as that shown in (b), the amount of the remaining liquid crystal can be further reduced.

[0042]

As described above, according to the present invention, the following effects can be obtained.

According to the first aspect, by performing the defoaming treatment while performing the stirring in a vacuum, the liquid crystal flows by the stirring, so that the air mixed in the liquid crystal is easily separated.
Since bubbles generated by separation are also easily released from the liquid surface, uniform processing can be performed quickly and reliably.

According to the second or fifth aspect, by applying vibration to the liquid crystal, separation of air and discharge of air bubbles can be promoted. In particular, air bubbles which are likely to remain in the inner part of the liquid crystal container are reduced. It can be efficiently eliminated by vibration.
Note that the vibration is desirably high-frequency ultrasonic vibration, and the vibration application position is desirably set at the back of the liquid crystal housing.

According to the third aspect, by heating the liquid crystal to such an extent that the liquid crystal is not affected, it is possible to reduce the viscosity of the liquid crystal while suppressing the volatilization of the effective component of the liquid crystal.
The defoaming process is promoted, and the efficiency of the process can be improved.

According to the fourth aspect, after performing the defoaming process in the liquid crystal supply container, the liquid crystal can be supplied as it is, so that the processed liquid crystal is easily used without being exposed to the atmosphere again. be able to.

According to the sixth aspect, without providing a separate heating means, the viscosity of the liquid crystal can be reduced to promote the defoaming treatment, thereby improving the efficiency of the treatment.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a state during a defoaming process in a first embodiment of a method for manufacturing a liquid crystal display device according to the present invention.

FIG. 2 is a plan view showing a shape of a stirrer in the first embodiment.

FIG. 3 is an explanatory diagram showing a state during a defoaming process in a second embodiment of the method for manufacturing a liquid crystal display device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Liquid crystal tank 12 Stirrer 13 Electromagnetic coil 14 Ultrasonic transducer 30 Cylinder 33 Piston part

Claims (6)

[Claims] 1. A method of manufacturing a liquid crystal display device in which a liquid crystal is injected into a liquid crystal panel to manufacture a liquid crystal display device, wherein the liquid crystal is subjected to a defoaming process while being stirred in a vacuum, and then the liquid crystal is subjected to the liquid crystal panel. A method for manufacturing a liquid crystal display device, characterized by injecting into a liquid crystal display. 2. The method for manufacturing a liquid crystal display device according to claim 1, wherein the defoaming process is performed while applying vibration to the liquid crystal by a vibration applying unit. 3. The liquid crystal display device according to claim 1, wherein in the defoaming treatment, heating is performed to such an extent that an essential component contained in the liquid crystal is not substantially volatilized. Method. 4. The liquid crystal supply container according to claim 1, wherein said liquid crystal is accommodated in a liquid crystal supply container provided with a liquid crystal pushing means configured to supply said liquid crystal to said liquid crystal panel. The method for manufacturing a liquid crystal display device, wherein the defoaming process is performed in a state where the pressure is reduced. 5. The liquid crystal display according to claim 4, wherein a vibration applying unit is provided around the liquid crystal supply container, and the defoaming process is performed while applying vibration to the liquid crystal by the vibration applying unit. Device manufacturing method. 6. The liquid crystal display device according to claim 2, wherein the vibration applying unit uses heat generated when the vibration is generated to such an extent that an essential component contained in the liquid crystal is not substantially volatilized. A method for manufacturing a liquid crystal display device, which is also used as a heating means for heating a liquid crystal display.