JP2689199B2 - Liquid crystal encapsulation method and liquid dispenser - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid dispenser suitable for liquid crystal encapsulation and liquid supply such as this liquid crystal encapsulation performed in the manufacture of liquid crystal display panels.

[0002]

2. Description of the Related Art As is well known, a liquid crystal display panel has a sandwich structure in which liquid crystal is sealed in a gap between two liquid crystal substrates on which transparent electrodes are formed, and the molecular alignment of the liquid crystal is determined by the voltage applied to the electrodes. The image is formed by changing it. Therefore, in the manufacture of a liquid crystal display panel, liquid crystal is injected into a gap between two liquid crystal substrates (hereinafter, referred to as two substrates) whose ends are sealed while leaving an opening for liquid crystal injection to open the opening. There is a liquid crystal encapsulation process for encapsulating.

FIG. 10 is an explanatory view of a conventional liquid crystal filling method. The conventional liquid crystal encapsulation method utilizes a so-called capillary phenomenon. That is, the bucket 1 in which the liquid crystal to be sealed is stored is arranged in a reduced pressure atmosphere, and the liquid crystal in the bucket 1 is immersed in the opening 20 of the two-piece substrate 2. Then, the liquid crystal in the bucket 1 is sucked up by the capillary phenomenon, enters the gap between the two substrates 2 and is injected. Then, after that, the opening 20 is sealed with resin or the like.

[0004]

In the conventional liquid crystal injection method as described above, since the liquid crystal is stored in a large bucket and sequentially used, it is impossible to completely use all the liquid crystal in the bucket. Liquid crystal remains at the bottom of the. The remaining liquid crystal is discarded, which naturally leads to an increase in manufacturing cost. Especially,
Many of the liquid crystal materials aiming at higher functionality these days are expensive, and if there is an amount of the liquid crystal material that is discarded without being used, it will greatly affect the increase in manufacturing cost. Further, in the conventional method in which the liquid crystal is stored in the bucket arranged in the depressurized atmosphere as described above, since the surface area of the liquid crystal in contact with the depressurized atmosphere is large and the contact time is long, the liquid crystal having high evaporative property is used. In that case, the deterioration of the liquid crystal due to the evaporation of the components cannot be ignored. The first object of the invention of the present application is to take such a problem into consideration, and propose a liquid crystal injection of a method different from the conventional one so as to reduce the amount of liquid crystal left unused as much as possible. It is possible to reduce the cost and reduce the evaporation of the components so that the liquid crystal can be enclosed without deteriorating.

Further, in the conventional method, since the liquid crystal is sucked up by the capillary phenomenon to inject the liquid crystal, it takes a long time to completely inject a predetermined amount of the liquid crystal. The injection time by the conventional method is, for example, 20 minutes to 3 minutes.
It takes about 0 minutes, which is a factor that hinders improvement in productivity in manufacturing liquid crystal display panels. A second object of the invention of the present application is to take such a problem into consideration, and in order to prevent the waste of the liquid crystal and contribute to the improvement of the productivity in the manufacturing process of the liquid crystal substrate, it is possible to inject the liquid crystal in a short time. Is to be able to complete.

On the other hand, in the field of the liquid dispenser to which the invention of the present application is directed, various types having a thin tube at the tip thereof such as a syringe are already well known. Insulating oil for injection is well known. However, there is no liquid dispenser capable of suitably injecting a liquid in a reduced pressure atmosphere like the liquid crystal injection that is performed when the liquid crystal display panel is manufactured.

Here, when the inventor of the present application examined the discharge of the liquid in a reduced pressure atmosphere using a conventionally known liquid dispenser, the movement of the piston and the discharge amount from the thin tube did not correspond well, and It has been found that it is difficult to release the liquid while controlling the release amount. The inventors of the present application have diligently studied the cause of this, and it has been found that bubbles are generated inside the dispenser due to the pressure drop in the surroundings, and the bubbles are discharged from the tip of the capillary. A third object of the invention of the present application is based on such a new finding, and it is possible to control the release amount with high accuracy even in a depressurized atmosphere by reducing the bubbles released from the tip of the thin tube. The purpose is to provide a liquid dispenser that can be used.

[0008]

In order to achieve the above first object, in the liquid crystal encapsulation method according to claim 1 of the present application, an end portion is sealed by leaving an opening for enclosing the liquid crystal. The liquid crystal substrates are held in a decompressed atmosphere with their openings facing upward, and the total number of drops is controlled by controlling the number of drops.
A predetermined amount of liquid crystal is injected from the opening using a liquid dispenser capable of controlling the discharge amount, and then,
The opening is sealed. Further, in order to achieve the second object, in the liquid crystal encapsulation method according to claim 2 of the present application, the lower substrate is held in a horizontal or nearly horizontal state, and a predetermined amount of liquid crystal is discharged in a controlled state. Use a liquid dispenser that allows even spacing on the surface of the lower substrate.
Liquid crystal is dropped at multiple locations , then the upper substrate is covered from above, and the edges of the upper substrate and lower substrate are sealed to seal the liquid crystal between the upper and lower substrates. To do.
Similarly, in order to achieve the above-mentioned first or second object, in the liquid crystal encapsulation method according to claim 3 of the present application, in the configuration according to claim 1 or 2 , the liquid dispenser includes a liquid crystal from a thin tube provided at the tip. the is intended to release dropwise to control the drop of quantity by setting the outer diameter of the capillary amount to be injected LCD and according to the surface tension of the liquid crystal. Further, in order to achieve the third object, a liquid dispenser according to claim 4 of the present application is a liquid dispenser used in a reduced pressure atmosphere, and a liquid reservoir for storing the liquid to be discharged and the liquid reservoir. A thin tube provided on the tip side of the vessel,
The tip may move inside the liquid stored in the liquid reservoir.
And a piston that discharges the liquid by sending it to a thin tube, and the liquid reservoir has a liquid reservoir opening in a portion other than a portion communicating with the thin pipe, and the liquid inside the liquid reservoir passes through the liquid reservoir opening. Come into contact with the surrounding decompressed atmosphere
In addition, the liquid reservoir is larger than the piston's cross-sectional area.
A liquid reservoir that is an internal space with a large cross-sectional area, and this liquid reservoir
The cross-sectional area corresponding to the cross-sectional area of the piston located on the delivery side of
And the delivery part, which is the internal space of the
The liquid moves by moving back and forth between the reservoir and the delivery unit.
It is a structure that is sent to a thin tube .

[0009]

Embodiments of the present invention will be described below. First, an embodiment of the invention of the liquid dispenser of the present application will be described. FIG. 1 is a schematic side sectional view of an embodiment of the liquid dispenser of the present invention. The liquid dispenser shown in FIG. 1 is roughly divided into a drive unit 3 arranged above.
And a motion conversion unit 4 arranged below the drive unit 3 for converting the rotational motion of the drive unit 3 into a vertical linear motion, and a motion conversion unit 4 arranged below the motion conversion unit 4 for vertical movement of the motion conversion unit 4. Is mainly transmitted, and a piston 5 for discharging liquid by performing vertical movement and a thin tube unit 6 arranged below the piston 5 and discharging liquid by vertical movement of the piston 5 are mainly configured. . The thin tube unit 6
Is detachable as a unit for replacing the thin tube 63, as described later.

First, the drive section 3 will be described. Drive unit 3
Is a motor 31, a drive part lower plate 32 on which the motor 31 is mounted and fixed, a drive part support 33 standing upright from the drive part support plate 32, and a drive part upper plate fixed on the drive part support 33. 34 and the like. The drive unit lower plate 32 is
There is a hole in the center, and the output shaft 311 of the motor 31
Extends downward through this hole. On the other hand, the drive unit upper plate 34 is provided with a mounting portion (not shown), and the mounting portion is mounted on a structure such as a liquid crystal injecting device in which this liquid dispenser is used. Is retained. The motor 31 is not limited, but a stepping motor, for example, is used.

Next, the motion conversion section 4 will be described. On the lower surface of the drive unit lower plate 32, three columns 41 are vertically provided and extend downward, and a horizontal intermediate base plate 42 is fixed to the lower ends of the columns 41. Motion converter 4
Are arranged inside the three columns 41. The motion converting section 4 is disposed inside the rotary cylinder 43, which has an upper end opening fitted and fixed to the output shaft 311 of the motor 31, and is arranged inside the rotary cylinder 43. Holding the driven screw body 44 that moves and the upper end of the piston 5,
It is mainly configured by a piston holding body 45 that transmits the vertical movement of the driven screw body 44 to the piston 5. First, the rotary cylinder 43 has an elongated shape having a bottom plate as shown in the drawing, and a screw hole is formed through the bottom plate portion. The driven screw body 44 has a round bar shape whose peripheral surface is threaded, and is screwed into a screw hole in the bottom plate portion of the rotary cylinder 43.
Then, the lower end of the screwed driven screw body 44 is exposed from the rotary cylinder 43 and extends downward.

On the other hand, the piston holder 45 arranged below the rotary cylinder 43 has a cylindrical shape as a whole, and the inside of its upper portion is hollow as shown in the figure. A through hole communicating with the hollow portion is formed on the upper surface of the piston holder 45. The lower portion of the driven screw body 44 exposed as described above enters the hollow portion inside the piston holding body 45 through this through hole, and a small disk-shaped screw head 441 is fixed to the lower end thereof. A coil spring 46 is arranged below the screw head 441 so as to fill the hollow portion. This coil spring 46
Has a relatively high rigidity, and acts as a rigid body that transmits the vertical movement of the driven screw body 44 to the piston 5 as it is when the liquid dispenser operates. The coil spring 46 is provided in consideration of an accident such that a piston head, which will be described later, is caught at the entrance of the delivery portion 622 of the liquid reservoir 62.

The piston 5 is fitted and held on the lower surface of the piston holder 45. That is, a mounting hole for the piston 5 is provided on the lower surface of the piston holding body 45, and the piston 5 is held and fixed to the piston holding body 45 by fitting the tip into this mounting hole. The piston 5 has a cylindrical piston head 51 with a slightly larger diameter at its tip. Further, on the side surface of the piston holder 45, a rotation stop pin 52 and a sensor blade 54 are provided on the left and right sides and extend laterally. On the other hand, a rotation stopping cylinder 53 is erected on a unit base plate 7 described later, and the column 41 is provided with an origin sensor 55 on the upper side and an overrun sensor 56 on the lower side.

On the other hand, the unit base plate 7 is attached to the lower side of the intermediate base plate 42 by the base plate attaching pins 71. That is, the tip of the base plate mounting pin 71 is screwed into and suspended from the intermediate base plate 42. The base plate mounting pin 71 penetrates the unit base plate 7, and its head is exposed from the lower surface of the unit base plate 7. A pin winding spring 72 is wound around the base plate mounting pin 71, and the pin winding spring 72 pushes the unit base plate 7 downward, so that the unit base plate 7 is predetermined with respect to the intermediate base plate 42. Are held at intervals. It should be noted that the intermediate base plate 42 and the unit base plate 7 are provided with an opening at the center for inserting the piston 5.

Next, the thin tube unit 6 will be described.
The thin tube unit 6 is arranged below the unit base plate 7 attached as described above, and the liquid reservoir holding plate 61 detachably held by the unit base plate 7 and the liquid reservoir holding plate. Liquid reservoir 62 fixed to the lower surface of 61
And a thin tube 63 fixed to the lower end of the liquid reservoir 62. The liquid reservoir holding plate 61 is attached to the unit base plate 7 by the same structure as the attachment structure of the unit base plate 7 to the intermediate base plate 42. That is, the tips of the three holding plate mounting pins 611 wound with the pin winding springs 612 are screwed into the unit base plate 7 and hung down, and the heads of the holding plate mounting pins 611 are exposed from the lower surface of the liquid reservoir holding plate 61. It has a structure in which the liquid reservoir holding plate 61 is pressed against the head and held by the winding spring 612. The intermediate base plate 42, the unit base plate 7, and the liquid reservoir holding plate 61 are all disc-shaped, and the base plate mounting pin 71
The holding plate mounting pin 611 is provided on the apex of an equilateral triangle on the peripheral end portion of the disk to hold it in a well-balanced manner. The base plate mounting pin 71
The holding plate attachment pins 611 are held at positions displaced from each other so as not to interfere with each other.

The liquid reservoir 62 has a substantially tubular shape as shown in FIG. 1, and has a liquid reservoir opening 620 at the upper end opening and a thin tube 63 fixed to the lower end opening portion. On the other hand, a relatively large holding plate opening 615 is provided at the center of the liquid reservoir holding plate 61.
The liquid reservoir 62 is fixed to the lower surface of the liquid reservoir holding plate 61 such that the liquid reservoir opening 620 at the upper end of the liquid reservoir 62 surrounds the holding plate opening 615. That is, the liquid can be poured into the liquid reservoir 62 through the holding plate opening 615 and the liquid reservoir opening 620,
The poured liquid is retained plate opening 615 and liquid reservoir opening 6
I am exposed to the atmosphere through 20. In addition, on the peripheral surface of the holding plate opening 615 of the liquid reservoir holding plate 61, the squeezing portion 61 is formed so that the opening is squeezed so as to increase upward.
6 are formed. The throttle portion 616 is formed for the purpose of suppressing the liquid from splashing out of the liquid reservoir 62 due to the discharge of bubbles from the liquid surface as described later. Also,
As shown in FIG. 1, the liquid reservoir 62 has a cross-sectional structure in which the inner diameter of the upper portion is large and the inner diameter of the lower portion is small. The upper part with a large inner diameter is the liquid reservoir 621,
The lower portion having a small inner diameter is the delivery portion 622.
The inner diameter of the delivery portion 622 is substantially the same as the outer diameter of the piston head 51, although there is a slight clearance for the piston head 51 to enter.

The thin tube 63 is a thin metal tube such as an injection needle, and has a thin tube fixing portion 631 at the base. In the thin tube 63, the thin tube fixing portion 631 is fixed to the lower end opening portion of the liquid reservoir 62 described above. on the other hand,
A heater 64 for heating the liquid crystal therein is wound around the outer peripheral surface of the liquid reservoir 62. This heater 64
Specifically, a linear sheath heater or the like is used. In addition, the thin tube unit 6 includes a protective tube 6 that protects the outer cover 65 and the thin tube 63 that cover the portion around which the heater 64 is wound.
It has 6 grades.

Next, the operation of this liquid dispenser will be described. First, the liquid discharged from the thin tube 63 is previously supplied and stored in the liquid reservoir 62. This supply may be performed by inserting a hose or the like into the liquid reservoir 62, for example.
Further, the liquid reservoir holding plate 61 may be removed from the unit base plate 7 as described later. The supplied liquid is preheated to a predetermined temperature of, for example, 100 ° C. or lower by the heater 64 wound around the outer peripheral surface of the liquid reservoir 62.

The original position of the piston 5 will be described as the upper limit position. At this position, the piston head 51 is located in the liquid reservoir 621 of the liquid reservoir 62. At this position, the sensor blade 54 is set to the origin sensor 55.
Has been confirmed by detecting. First, when a drive signal is sent from the controller (not shown) to the motor 31,
The rotary cylinder 43 rotates via the output shaft 311. The rotary motion of the rotary cylinder 43 is caused by the driven screw body 4 that is screwed.
4, the rotational movement of the piston holding body 45 interlocking with the driven screw body 44 is restricted as described later, so that the driven screw body 44 does not rotate but only moves up and down according to the direction of rotation. To do.

FIG. 2 is a schematic plan view illustrating a structure for restricting the rotational movement of the piston holder 45. As described above, the rotation stopper pin 52 is provided on the side surface of the piston holder 45.
Is provided and extends laterally, and the unit base plate 7
A rotation-stopping cylinder 53 is erected on this. As shown in FIG. 2, the rotation-stopping cylinder 53 is composed of two semi-cylindrical members arranged facing each other with a predetermined gap, and the rotation-stopping pin 52 has two rotation-stopping pins. It is located in one of the gaps of the cylinder 53. Therefore, even if the piston holding body 45 tries to rotate in synchronization with the rotation of the driven screw body 44, the rotation stopping pin 52 causes the rotation stopping cylindrical body 5 to rotate.
It is locked by 3 and is regulated so that it does not rotate. The above-mentioned sensor vane 54 is located in the other gap portion between the two rotation stopping cylinders 53, and is exposed from the rotation stopping cylinder 53 to allow the origin sensor 55 and the overrun sensor. The position is detected by 56. With such a rotation restriction structure, the rotational movement of the rotary cylinder 43 is converted into the vertical movement of the driven screw body 44 and transmitted to the piston 5. Since the original position of the piston 5 is the upper limit position, the motor 31 first rotates in the direction in which the piston 5 descends, lowers the piston 5 to a lower limit position below a predetermined distance, and stops rotating.

FIG. 3 is a partial sectional view for explaining the operation of the piston of FIG. As shown in FIG. 3, when the piston 5 descends, the piston head 51 submerged in the liquid in the liquid reservoir 62 enters the delivery unit 622 from the liquid reservoir 621 of the liquid reservoir 62. Since the inner diameter of the delivery portion 622 and the outer diameter of the piston head 51 are substantially equal, the piston head 5
1 enters the delivery section 622 and is in a pressurized state, and pushes out the liquid in the delivery section 622. By pushing out this liquid, one drop is ejected from the tip of the lower thin tube 63.
The discharged liquid is heated to a predetermined temperature by the heater 64. This is because in the liquid crystal injection described later, in the case of a liquid crystal having a high viscosity, it is necessary to lower the viscosity by heating to facilitate the injection.

After the elapse of the predetermined time required for discharging one drop, a signal is sent from the controller to the motor 31.
The motor 31 starts rotating in the opposite direction, raises the piston 5 to the initial upper limit position, and stops rotating. As the piston 5 rises, the piston head 51 rises, and the delivery portion 62
2 and returns to the original position of the liquid reservoir 621. The drop control of the liquid dispenser is most surely made by moving the piston 5 up and down to drop the liquid one by one. That is, this is a method of controlling one drop by moving the piston 5 up and down once between the position A and the position B in FIG. Then, the insertion depth D of the piston head 51 is appropriately set in accordance with the viscosity of the liquid or the like so that one drop of liquid is dropped in one stroke.

Further, by making the piston 5 move from the position A in FIG. 3 to the position B'or B ", that is, by increasing D, two or more drops of liquid are dropped by one vertical movement. In that case, the piston 5
The number of drops to be moved once at a certain depth D is experimentally obtained in advance, and how many times to move up and down should be decided in advance according to the total drop amount. . In addition, the piston 5 is lowered to the position B to drop one drop and then stopped, and after a predetermined time, it is further dropped to the position B ′ to drop the second drop and further dropped to the position B ″ to drop three drops. An example of control in which the amount of droplets is dropped is also possible, that is, an example of control in which D is incremented in small increments, and such D is usually set by the number of steps of the stepping motor 31 described above.

When the liquid dispenser having such an operation is used in a reduced pressure atmosphere, bubbles may be generated inside the liquid reservoir 62. The main cause of this bubble generation is that the volatile components of the liquid are rapidly vaporized by depressurization. Further, when supplying the liquid to the liquid reservoir 62 at atmospheric pressure, the ambient air may be trapped and mixed in the liquid reservoir 62 and originally exist in the liquid reservoir 62. is there. That is, the entrained air may become bubbles and adhere to the inner wall of the liquid reservoir 62, or may enter the gap of the joint surface with the liquid reservoir holding plate 61 and stagnant.
In any case, the bubbles in the liquid stored in the liquid reservoir 62 are attracted and moved by the reduced pressure atmosphere around them.

Here, similar to the conventionally known liquid dispenser, the liquid reservoir 62 is provided in addition to the portion communicating with the thin tube 63.
If there is no opening in the bubble, the bubble has no choice but to move toward the thin tube 63 and is eventually discharged from the tip of the thin tube 63.
When air bubbles are discharged from the tip of the thin tube 63,
The amount of droplets formed at the tip of the thin tube 63 is not constant, and it becomes impossible to control the amount of droplets as described above. Also,
Piston 5
The stroke amount and the liquid discharge amount do not correspond, and it becomes impossible to control the discharge amount.

However, in the liquid dispenser of this embodiment, as described above, the relatively large liquid reservoir opening 620 and the holding plate opening 615 are provided,
The liquid inside is in contact with the reduced pressure atmosphere. Therefore, most of the bubbles inside the liquid move upward and are discharged from the liquid surface, and are not discharged from the thin tube 63. For this reason, the release amount can be controlled even when used in a reduced pressure atmosphere, and the release amount control of various types as described above can be suitably performed.

Next, the structure for replacing the thin tube 63 in the above liquid dispenser will be described. In this liquid dispenser, the liquid reservoir holding plate 61
Is attached to and detached from the unit base plate 7, and the thin tube unit 6
The thin tube 63 is replaced. FIG. 4 is a schematic plan view for supplementarily explaining the attachment / detachment structure of the liquid reservoir holding plate.
It is a view from the arrow. As shown in FIG. 4, the liquid reservoir holding plate 61 is provided with three through holes 610 concentrically. Each through hole 610 has a relatively large circular portion and a thin arc-shaped portion.

First, when removing the reservoir holding plate 61, the head of the holding plate mounting pin 611 is located at the end of the elongated portion of the through hole 610 as shown by the broken line in FIG. While holding the reservoir holding plate 61 by hand and turning it slightly, the head of the holding plate mounting pin 611 is positioned in the large circular portion of the through hole 610. Then, in this state, the liquid reservoir holding plate 61 can be removed by pulling it down as it is. Also,
When attaching the liquid reservoir holding plates 61 of the other thin tube units 6, they are attached in the reverse order of the above. In any case, since the thin tube unit 6 can be attached and detached with one touch, this liquid dispenser is easy to replace the thin tube 63 and is convenient.

Next, another embodiment of the liquid dispenser of the present invention will be described. FIG. 5 is a schematic view illustrating another embodiment of the liquid dispenser of the present invention. The liquid dispenser shown in FIG. 5 has a liquid reservoir 62 in the shape of a cylinder, a piston 5 that moves forward and backward inside the liquid reservoir, and a thin tube 63 provided at the tip of the liquid reservoir.
It is mainly formed from. Then, on the side surface of the liquid reservoir, an auxiliary liquid reservoir portion 623 extends laterally as shown in the drawing and is bent upward. The upper end of the auxiliary liquid reservoir 623 is an opening, and this opening is the liquid reservoir opening 620.
It has become. That is, the liquid inside the liquid reservoir 62 comes into contact with the surrounding reduced pressure atmosphere at this portion. In addition, a piston head 51 provided at the tip of the piston 5
Is brought into contact with the inner wall surface of the liquid reservoir 62, and the liquid inside can be pressurized by the forward movement of the piston 5.

In the liquid dispenser of this example, first, the piston 5 is retracted and the liquid reservoir opening 62 is opened.
The liquid is supplied from the portion of 0 and stored in the liquid reservoir 62. Then, the piston 5 is advanced and retracted to discharge the liquid drop by drop or continuously from the tip of the thin tube 63. At this time, as in the above-described embodiment, bubbles are generated inside the liquid reservoir 62, but most of the generated bubbles are discharged from the liquid surface of the liquid reservoir opening 620 which is in contact with the reduced pressure atmosphere. . Therefore, the discharge amount control does not become impossible due to the discharge of bubbles from the tip of the thin tube 63, and the discharge amount control according to the stroke length of the piston 5 and the like can be suitably performed also in this example.

The liquid dispenser of each of the embodiments described above has many suitable applications other than the liquid crystal injection method described later. For example, injection of a two-pack type epoxy resin into a precision transformer can be mentioned.

Next, regarding the liquid crystal encapsulation method of the present invention,
The following two embodiments will be described. That is, in the first embodiment, the process of assembling the two substrates by sealing the ends of the two substrates so that the opening is left is the same as the conventional method, and the process of injecting the liquid crystal is different. Is. The second embodiment is a method completely different from the conventional method including the method of sealing the end portion.

First, the first embodiment will be described. As described above, the method of this embodiment is different only in the step of injecting liquid crystal, and the description of the other steps is omitted. FIG. 6 is an explanatory diagram of the liquid crystal injection process of the first embodiment.
The liquid crystal is actually sealed by a series of devices provided along the transport line. FIG. 6 shows an outline of a device of a portion for injecting liquid crystal among them. FIG.
The apparatus shown in FIG. 1 includes a decompression chamber 8, a vacuum pump 9 for decompressing the decompression chamber 8, and a substrate cassette 2 containing two substrates 2.
1 on which the table 1 is placed, the above-mentioned liquid dispenser 10 arranged above the table 22, and a moving mechanism 11 for horizontally moving the liquid dispenser 10.
It is mainly composed of

First, as in the conventional case, some of the two substrates 2 in which the ends of the two substrates are sealed leaving the opening 20 are housed in the substrate cassette 21. The two substrates 2 in the substrate cassette 21 have a vertical posture, and the opening 20 faces upward. Such two substrates 2 are carried into the decompression chamber 8 together with the substrate cassette 21, and the substrate cassette 21 is moved to the table 22.
It is placed on and fixed. In the substrate cassette 21, the opening 20 of the two substrates 2 is the thin tube 63 of the liquid dispenser 10.
Is arranged so as to be in the vicinity of the tip of the. In this state, the vacuum pump 9 is operated to set the inside of the decompression chamber 8 to 0.1
Reduce the pressure to about Torr or lower. Then, the liquid dispenser 10 is operated as described above to inject the liquid crystal drop by drop from the opening 20.

At this time, as will be described later, since the amount of one drop of liquid crystal to be injected can be controlled in milligram order by the outer diameter d of the thin tube 63, the number of drops is determined in advance in consideration of the total amount to be injected. Then, the piston 5 is moved up and down by this number of drops. That is, a drive signal is sent from the controller to the motor 31 so that the piston 5 moves up and down by the number of drops. Then, when the injection of the liquid crystal into one of the two substrates 2 is completed, the moving mechanism 11 operates and the liquid dispenser 10 is horizontally moved for the injection into the other two substrates 2 stored in the same substrate cassette 21. By moving, the tip of the thin tube 63 is positioned near the opening 20 of the other two substrates 2. Then, the liquid crystal injection is repeated as described above. In this way, all the two substrates 2 in the substrate cassette 21 are
When the liquid crystal injection into the substrate cassette 21 is completed, the substrate cassette 21 is unloaded from the decompression chamber 8 and sent to the next opening sealing step, where the opening 20 is sealed as in the conventional case. The liquid dispenser 10 is not provided with the moving mechanism 11 to move the liquid dispenser 10, but the substrate cassette 21 is placed and fixed on the XY moving table as shown in FIG. You may make it move the 2nd one.

Next, the control of the liquid crystal injection amount by setting the outer diameter of the thin tube 63 will be described. It is well known that the following formula holds for the swelling amount of the liquid spherically swelling from the lower end of the thin tube 63 as shown in FIG. mg = πdγ cos θ In the above equation, m is the mass of the bulging liquid, g is the gravitational acceleration, d is the outer diameter of the thin tube 63, γ is the surface tension of the liquid, and θ is the tangent line and the end surface of the bulging liquid at the end surface of the thin tube 63. Is the angle between the normals of. Of these, g and π are known, and γ and θ are values unique to the liquid and can be regarded as constants. Therefore, the mass m of the liquid swelling from the end face of the thin tube 63 depends only on the outer diameter d of the thin tube 63, and the mass m of one drop of liquid can be defined by selecting an appropriate d.

Therefore, the weight m of one drop of liquid crystal can be obtained by previously checking γ and θ of the liquid crystal to be injected and substituting these values and d of the thin tube 63 to be used in the above equation. . From this, calculate the required number of liquid crystal drops,
The motor 31 is controlled as described above. At this time, the smaller the amount of the liquid crystal in one drop is, the more accurately the total amount of the liquid crystal can be controlled. However, since the number of droplets is large and the injection time is long, d is appropriately selected in consideration of this side. The replacement of the thin tube 63 is performed for each thin tube unit 6 as described above, but it goes without saying that only the thin tube 63 may be replaced. In this case, it is necessary to prevent liquid crystal from remaining in the liquid reservoir 62. In any case, if the liquid crystal is injected drop by drop and the amount of the drop is controlled by the outer diameter of the thin tube 63, a finely enclosed amount of milligram order can be adjusted.

The liquid crystal encapsulation method of this embodiment, which encloses the liquid crystal in this manner, has the following many effects as compared with the conventional method. (1) Since the liquid crystal can be used to the end without waste,
An increase in manufacturing cost can be suppressed. (2) Since the surface area of the liquid crystal in contact with the reduced pressure atmosphere is much smaller than in the conventional case, the deterioration due to the evaporation of the components is almost eliminated. (3) By appropriately selecting the outer diameter of the thin tube, the enclosed amount can be controlled with high accuracy. Note that the liquid crystal encapsulation method of the present invention can be implemented in addition to the method of determining the amount of one drop of liquid crystal by the above formula. For example, a method is possible in which the amount of one drop of liquid crystal when a certain liquid crystal is dropped using a certain thin tube 63 is experimentally obtained in advance and injection is performed under the same conditions. further,
The present invention can be implemented even when liquid crystals are continuously injected instead of being injected one by one as in the above-described embodiment. Although the control of the injection amount is rough, it is possible to obtain the effect of preventing the liquid crystal from being wasted and deterioration. still,
The liquid dispenser 10 is preferably arranged in a vertical posture with the tip of the thin tube 63 facing downward, but may be arranged obliquely or horizontally in consideration of space saving and the like.

Next, a second embodiment of the liquid crystal enclosing method of the present invention will be described. FIG. 7 is a side sectional view for explaining a second embodiment of the liquid crystal encapsulation method of the present invention, and FIG. 8 is a plan view of the lower substrate in the method of FIG.

First, as shown in FIG. 7A, the ultraviolet curable resin 24 is applied to the end surface of the lower substrate 23.
As shown in FIG. 8, the ultraviolet curable resin 24 is applied so as to draw a closed square loop along the end of the rectangular substrate. Next, as shown in FIG. 7B, the lower substrate 2
A predetermined amount of liquid crystal L is dropped on the surface of No. 3 and inside the portion coated with the ultraviolet curable resin 24. The liquid crystal L is dropped at a plurality of locations at equal intervals as shown in FIG. 8, and the number of drops is predetermined as described above according to the total amount of the liquid crystal and the amount of one drop of liquid crystal. After this,
As shown in FIG. 7C, the upper substrate 25 is covered from above and the two substrates 23 and 25 are bonded. And
As shown in (c), the ultraviolet curable resin 24 is cured by the ultraviolet lamp 27, and the end portion of the lower substrate 23 and the upper substrate 2 are
And the end of No. 5 is bonded. This allows the two substrates 2
A predetermined amount of liquid crystal L is enclosed between 3 and 25.

FIG. 9 is a schematic view of a liquid crystal dropping device used for dropping the liquid crystal shown in FIG. 7B. The liquid crystal dropping device shown in FIG. 9 includes a decompression chamber 8, a vacuum pump 9 for decompressing the decompression chamber 8, an XY moving table 26 arranged below the decompression chamber 8, and an XY moving table 26. It is mainly composed of a liquid dispenser 10 and the like arranged above. As is apparent from the figure, the substrate cassette is not used in the injection step of this embodiment, and the lower substrates 23 coated with the ultraviolet curable resin 24 are carried into the decompression chamber 8 one by one. The loaded lower substrate 23 is placed and fixed on the XY moving table 26. In this state, the vacuum pump 9 is operated so that the inside of the decompression chamber 8 is also 0.1 Torr.
Reduce pressure to a pressure of about r or less. Then, the liquid dispenser 10 is operated as described above to drop the liquid crystal drop by drop. After a predetermined number of drops, the XY moving table 26 operates to horizontally move the lower substrate 23, and the next drop part is positioned below the thin tube 63. Then, similarly, a predetermined number of liquid crystals are dropped. In this way, after the liquid crystal is dropped at each position shown in FIG. 7, the lower substrate 23 is carried out of the decompression chamber 8 and sent to the next upper substrate bonding step.

The lower substrate 23 does not have to be held "horizontally" in a strict sense, and it is needless to say that the lower substrate 23 may be tilted and held within a range that does not hinder practical use. Further, as an actual apparatus, it is often configured such that one apparatus can also apply an ultraviolet curable resin to the lower substrate. That is, a dispenser for supplying the ultraviolet curable resin is arranged inside the decompression chamber of FIG. 9, and the XY moving table 26 is operated to position a predetermined portion of the end portion of the lower substrate 23 at a position below the dispenser. , So that the resin can be applied. However, it is needless to say that the liquid dispenser 10 may be provided with a moving mechanism as in the example shown in FIG. 6 described above.

Since the method of the second embodiment is not the conventional suction method by the capillary phenomenon, the liquid crystal encapsulation can be completed in a short time, which can contribute to the improvement of productivity. Further, since the capillary phenomenon is not used, the method of this embodiment does not necessarily have to be performed in a reduced pressure atmosphere. However, in order to fill the liquid crystal between the two substrates without leaving any gap, it is effective to perform it in a reduced pressure state. Also, dropping in a reduced pressure atmosphere does not allow impurities such as dust or dust to enter the liquid crystal. It also has the effect of preventing deterioration of components due to gas mixture.
It is also conceivable to drop the liquid crystal at atmospheric pressure and then reduce the atmosphere to seal it, but since the liquid crystal may foam and scatter on the substrate during the evacuation time by the vacuum pump, It is considered that dropping of liquid crystal in a reduced pressure atmosphere is important.

In the second embodiment, the terms "lower substrate" and "upper substrate" do not necessarily mean "lower side" and "upper side" in actual use.

As described above, according to the liquid crystal encapsulation method according to claim 1 of the present application, the amount of wasted liquid crystal can be reduced, so that the cost can be reduced, and the evaporation of components can be achieved. Since the amount is reduced, the liquid crystal can be filled without deteriorating the liquid crystal. Further, according to the liquid crystal encapsulation method described in claim 2 of the present application, in addition to the effect of claim 1, since the encapsulation time can be shortened, it is possible to contribute to the improvement of the productivity in the manufacturing process of the liquid crystal display panel. Further, according to the liquid crystal encapsulation method described in claim 3 of the present application, in addition to the effect of claim 1 or 2, the liquid crystal encapsulation amount can be controlled with high accuracy for encapsulation. Further, according to the liquid crystal encapsulation method according to claim 4 of the present application, in addition to the effect of claim 1 or 2, since the amount of liquid crystal enclosed is controlled by the outer diameter of the thin tube, the liquid crystal encapsulation can be performed with higher accuracy. You can Further, according to the liquid dispenser of claim 5 of the present application, the bubbles emitted from the tip of the thin tube are extremely reduced,
The release amount can be controlled with high accuracy even in a reduced pressure atmosphere.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view of an embodiment of a liquid dispenser of the present invention.

FIG. 2 is a schematic plan view illustrating a structure for restricting rotational movement of a piston holder.

FIG. 3 is a partial cross-sectional view for explaining the action of the piston of FIG.

FIG. 4 is a schematic plan view for supplementarily explaining the structure for attaching and detaching the liquid reservoir holding plate, which is a view taken along the line AA of FIG.

FIG. 5 is a schematic view illustrating another embodiment of the liquid dispenser of the present invention.

FIG. 6 is an explanatory diagram of a liquid crystal injection step of the first embodiment of the liquid crystal encapsulation method of the present invention.

FIG. 7 is a side sectional view for explaining a second embodiment of the liquid crystal sealing method of the present invention.

FIG. 8 is a plan view of a lower substrate in the method of FIG.

9 is a schematic view of a liquid crystal dropping device used for dropping liquid crystal in FIG. 7 (b).

FIG. 10 is an explanatory diagram of a conventional liquid crystal sealing method.

[Explanation of symbols]

 10 Liquid Dispenser 2 Two-Piece Substrate 20 Opening 5 Piston 51 Piston Head 62 Liquid Reservoir 620 Liquid Reservoir Opening 621 Liquid Reservoir 622 Delivery Part 63 Fine Tube

Claims (4)

(57) [Claims] 1. A liquid crystal encapsulation method for encapsulating liquid crystal in a gap between two liquid crystal substrates, the two liquid crystal substrates having end portions sealed so as to leave an opening for enclosing the liquid crystal, Hold it in a decompressed atmosphere with its opening facing upward, and drip
It is possible to control the total release amount by controlling the number.
A liquid crystal encapsulation method, which comprises injecting a predetermined amount of liquid crystal from the opening using a possible liquid dispenser and then sealing the opening. 2. A liquid dispenser capable of holding the lower substrate in a horizontal or nearly horizontal state and discharging a predetermined amount of liquid crystal in a controlled state is evenly distributed on the surface of the lower substrate. The liquid crystal is dropped on a plurality of places at intervals, and then the upper substrate is covered from above, and the end portions of the upper substrate and the lower substrate are sealed so that the space between the upper substrate and the lower substrate is increased. A liquid crystal encapsulation method characterized by encapsulating liquid crystal. 3. The liquid dispenser discharges liquid crystal drop by drop from a thin tube provided at a tip of the liquid dispenser.
The liquid crystal encapsulation method according to claim 1 or 2 , wherein the amount of one drop is controlled by setting the outer diameter of the capillary according to the amount of liquid crystal to be injected and the surface tension of the liquid crystal. 4. A liquid dispenser used in a reduced-pressure atmosphere, the liquid reservoir storing a liquid to be discharged,
The thin tube provided on the tip side of this reservoir and the inside of the reservoir
By moving the tip inside the liquid stored in
The liquid reservoir has a piston for sending the liquid to the thin tube and discharging it.The liquid reservoir has a liquid reservoir opening in a portion other than the portion communicating with the thin pipe, and the liquid inside the liquid reservoir is surrounded by the liquid reservoir opening. It is adapted to contact the reduced pressure atmosphere, further
In addition, the liquid reservoir has a larger cross-sectional area than the piston.
On the delivery side of the liquid reservoir that is the internal space of
Positioned inside space with a cross-sectional area equivalent to that of the piston
And the tip of the piston feeds the liquid reservoir.
Liquid is sent to the thin tube by moving back and forth between the outlet and
Dispenser for liquids, which is characterized in that