JP4244529B2 - Method and apparatus for assembling liquid crystal substrate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal substrate assembling method and an assembling apparatus for holding substrates that are objects to be bonded with a liquid crystal agent interposed therebetween, and bonding the substrates by narrowing the interval between the substrates.
[0002]
[Prior art]
For the manufacture of liquid crystal display panels, two glass substrates with transparent electrodes and thin film transistor arrays are bonded to each other at a suitable position on the outer periphery of the substrate and the sealing agent provided in a square shape on the periphery of the substrate. There is a process in which liquid crystal is sealed in a space formed by each substrate and an adhesive (hereinafter also referred to as “sealing agent”).
[0003]
Conventionally, as a method of laminating a substrate when sealing the liquid crystal, the liquid crystal is dropped on one substrate drawn in a pattern (letter shape) in which a sealing agent is closed so as not to provide an injection port. Then, the other substrate is placed above one substrate in the vacuum chamber, and the upper and lower substrates are bonded together by applying a pressure while reducing the distance between the other substrate and one substrate in a vacuum state. There is a method disclosed in Japanese Patent Laid-Open No. 62-89025.
[0004]
[Problems to be solved by the invention]
However, in the method disclosed in Japanese Patent Laid-Open No. 62-89025, the liquid crystal agent is dropped onto the substrate, so intermolecular force generated between the substrate film surface and the liquid crystal agent, dropping impact, or sticking. There is an inconvenience that color unevenness occurs due to deformation or damage of the film surface caused by the reaction force of the liquid crystal agent (particularly the reaction force accompanying increase in the viscosity of the liquid crystal agent) due to the pressurization at the time of alignment, and further due to poor alignment. It was. In addition, there is an inconvenience that an interface of the dropped liquid crystal agent is generated in a narrow gap state between the upper and lower substrates during the bonding process and color unevenness occurs. Furthermore, due to the entrainment of air when the liquid crystal agent is dropped, the liquid crystal agent is trapped between the substrate on which moisture, impurities, etc. in the air are bonded, which causes an oxidation phenomenon and the like. There was an inconvenience that it was left as. And there was a disadvantage that uneven color occurred in the assembled liquid crystal panel due to the dropping marks.
[0005]
The present invention improves an inconvenience of the conventional example, and a liquid crystal substrate assembling method and an assembling apparatus capable of producing a liquid crystal panel free from display unevenness due to a liquid crystal agent dripping trace or a liquid crystal agent interface at the time of bonding. The purpose is to provide
[0006]
[Means for Solving the Problems]
  In order to achieve the above object, in the present invention, one of the two substrates to be bonded is held on the lower surface of the pressure plate and the other substrate coated with the sealing agent in a closed pattern is placed on the table. After holding the liquid crystal agent on the other substrate, narrow the gap between the opposing substrates.With the sealing agent applied to the other substrateIn a method of assembling a liquid crystal substrate to be bonded, a nozzle positioning step of positioning a nozzle tip for discharging a liquid crystal agent at a predetermined height with respect to the surface of the substrate above the other substrate, and on the other substrate The liquid crystal agent is applied at a predetermined angle with respect to the orientation direction of the substrate so that the slower spreading speed of the liquid crystal agent is close to the sealant, and at least one substantially linear coating pattern set in advance. With liquid crystal coating processIn this liquid crystal agent application step, an inert gas is supplied to the periphery of the nozzle tip before application of the liquid crystal agent, and the liquid crystal agent is applied while simultaneously discharging the liquid crystal agent and the inert gas.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a liquid crystal substrate assembling apparatus according to the present invention will be described with reference to FIGS.
[0008]
The configuration of the liquid crystal substrate assembly apparatus of this embodiment is shown in FIG. The apparatus for assembling the liquid crystal substrate is roughly divided into a liquid crystal pattern application unit S1 which is a liquid crystal application device, and a pressure plate 27 for holding the upper substrate 1b, and a substrate bonding unit for pressing the upper substrate 1b to the lower substrate 1a. S2 and an XYθ stage T1 including a table 9 on which the lower substrate 1a is placed and held. Here, the liquid crystal pattern application unit S1 and the substrate bonding unit S2 are supported by a frame 3 composed of a plurality of support columns erected on the gantry 2 and a horizontal member that crosses between the support columns. Arranged adjacent to each other, the XYθ stage T1 is movably disposed between the liquid crystal pattern application unit S1 and the substrate bonding unit S2 and the gantry 2. Hereinafter, each of these components will be described in detail.
[0009]
The liquid crystal pattern application unit S1 includes a dispenser 17 including a nozzle 18 for applying a desired amount of liquid crystal agent on the lower substrate 1a (main surface of the lower substrate 1a) placed and held on a table 9 described later, and the dispenser 17 And a Z-axis stage 15 that moves in the vertical direction (the Z-axis direction shown in FIG. 1), a motor 16 that urges the vertical movement of the Z-axis stage 15, and a dispenser 17. And a substrate surface height measuring device LS held on the Z-axis stage 15. The thus configured liquid crystal pattern application unit S1 is supported by holding the Z-axis stage 15 with a bracket 14 projecting from a frame 3 to be described later that supports the substrate bonding unit S2.
[0010]
Here, the dispenser 17 will be described. A pressure source (for example, a pump) (not shown) and an air filter are connected to the dispenser 17, and an inert gas (for example, nitrogen gas or argon gas) sent from the pressure source is passed through the air filter. An inert gas that does not contain impurities such as dust is sent in. As shown in FIG. 3, the inert gas is fed into a reservoir 17a of a dispenser 17 in which a liquid crystal agent is stored and a gas supply unit 18a that supplies the inert gas to the lower substrate 1a. By supplying the inert gas to the reservoir portion 17a in this way, the liquid crystal agent is pumped, whereby the liquid crystal agent is applied to the lower substrate 1a from the nozzle tip portion 18b. Moreover, the gas supply part 18a is covered by the nozzle front-end | tip part 18b, and an inert gas is discharged so that the nozzle front-end | tip part 18b may be enclosed. The shape of the tip (liquid crystal agent discharge port) of the nozzle tip 18b of the present embodiment is substantially circular. By using the double nozzle in this way, it becomes possible to apply the liquid crystal agent without touching the air as much as possible.
[0011]
In the case of applying a liquid crystal agent using the above-described dispenser 17, in general, the inert gas is discharged simultaneously with the application of the liquid crystal agent. Here, in the present embodiment, in addition to this, since the discharge of the inert gas is started before the application of the liquid crystal agent is started, the air on the surface of the lower substrate 1a is removed, so that the liquid crystal The possibility of the agent coming into contact with air can be further reduced.
[0012]
Next, the substrate surface height measuring device LS will be described. For example, the substrate surface height measuring device LS measures the time from when an ultrasonic wave is emitted toward the main surface of the lower substrate 1a until the reflected wave returns, and based on the time, the substrate surface height is measured. The distance between the measuring device LS and the lower substrate 1a is measured. The substrate surface height measuring device LS is used, for example, when adjusting the nozzle position of the dispenser 17 as described later. That is, when the Z-axis stage 15 is moved up and down so that the nozzle position becomes a desired height with respect to the lower substrate 1a, the measurement distance by the substrate surface height measuring device LS is used.
[0013]
Here, although not shown in FIG. 1, a dispenser for discharging a sealing agent is disposed near the dispenser 17 for applying the liquid crystal agent. The dispenser for supplying the sealing agent is fixed to the frame 3 via a bracket (not shown) in the same manner as the dispenser 17 for applying the liquid crystal agent.
[0014]
The substrate bonding unit S2 is disposed in the upper chamber unit 21 through a shaft 29, and is provided with a suction adsorption mechanism and an electrostatic device. It consists of a pressure plate 27 provided with a suction mechanism, each of which can move up and down independently.
[0015]
Specifically, the upper chamber unit 21 is formed with through holes (not shown) through which the plurality of shafts 29 are inserted. An upper portion of the upper chamber unit 21 covers a gap between the through hole and the shaft 29 and houses a linear bush and a vacuum seal that covers the shaft 29. A cylinder 22 is provided that fixes to a top of the upper chamber unit 21 a member that is fixed to the frame and reciprocates in the vertical direction within the main body. With this configuration, the upper chamber unit 21 moves in the vertical direction by the cylinder 22 using the shaft 29 as a guide.
[0016]
The vacuum seal of the housing 30 described above is formed by combining the upper chamber unit 21 and the lower chamber unit 10 to form a decompression chamber, and even if the housing 30 is deformed at this time, the gap between the through hole and the shaft 29 is reduced. Built-in to prevent vacuum leakage. Therefore, even if a load is applied to the shaft 29 due to the deformation of the decompression chamber, the force can be absorbed. Further, deformation of the pressure plate 27 fixed to one end of the shaft 29 can be prevented, and the substrate 9 is held on the upper substrate 1b held on the pressure plate 27 and the table 9 when the substrates 1a and 1b are bonded as will be described later. Bonding can be performed while maintaining parallel to the lower substrate 1a.
[0017]
Here, a flange 21 a is provided at the lower end portion (periphery of the opening) of the upper chamber unit 21 for hermetically sealing the inside of the decompression chamber when the decompression chamber is formed together with the lower chamber unit 10.
[0018]
Further, on one side portion of the upper chamber unit 21, in order to depressurize the inside of the decompression chamber, a piping hose 24 communicating with the decompression chamber, a vacuum valve 23 disposed in the middle of the piping hose 24, A vacuum pump (not shown) connected to the piping hose 24 is provided.
[0019]
Furthermore, the other side of the upper chamber unit 21 has a gas purge valve 25 communicating with the pressure reducing chamber and one end connected to the gas purge valve 25 in order to return the reduced pressure chamber to atmospheric pressure. A gas tube 26 and a pressurizing pump for sending nitrogen, clean dry air, or the like connected to the other end of the gas tube 26 are provided.
[0020]
Here, a plurality of windows for observing the alignment marks of the substrates 1a and 1b are provided on the upper chamber unit 21 through mark recognition holes (not shown) formed in the pressure plate 27. In this case, an image recognition camera (not shown) disposed above the window of the upper chamber unit 21 is used for observing the alignment mark, and the alignment marks on the substrates 1a and 1b are shifted by the image recognition camera. Measure.
[0021]
Subsequently, the pressure plate 27 is fixed to one end of the shaft 29 as described above. Here, the other end of the shaft 29 is fixed to the housing 31, and a linear guide 34 disposed on both sides of the housing 31 and a guide portion 3 a provided on the frame 3 that engages with the linear guide 34. Thus, the pressure plate 27 can be moved up and down. More specifically, the load includes a housing 32 disposed on the upper portion of the housing 31, a load meter 33 disposed on the upper surface of the housing 32, and a female screw portion threaded in the vertical direction. A nut housing 37 disposed in the upper part of the total 33, a ball screw 36 that is rotatably engaged by a female screw portion of the nut housing 37, and an output shaft that rotates the ball screw 36 about its axis The pressure plate 27 is moved up and down by driving the motor 40. In this case, the motor 40 is fixed to a bracket 38 on the frame 35 disposed on the upper portion of the frame 3.
[0022]
With this configuration, the pressure plate 27 holding the upper substrate 1b is lowered by driving the motor 40, and the upper substrate 1b is brought into close contact with the lower substrate 1a on the table 9 to apply the pressure necessary for bonding. Can be given. Here, the load meter 33 described above functions as a pressure sensor, and can control the motor 40 based on the sequentially fed back signal to apply a desired pressure to each of the substrates 1a and 1b. .
[0023]
As described above, the pressure plate 27 that moves up and down as described above includes the suction suction mechanism and the electrostatic suction mechanism. The suction suction mechanism includes a plurality of suction holes (not shown) formed from the lower surface of the pressure plate 27, a suction suction joint 41 communicating with each suction hole and disposed in the upper chamber unit 21, and the suction suction. The suction tube 42 communicates with the joint 41 for use, and a vacuum pump (not shown) connected to the suction tube 42. The suction suction mechanism configured as described above drives the vacuum pump in the atmosphere to hold the upper substrate 1b in close contact with the lower surface of the pressure plate 27 by vacuum suction (or suction suction).
[0024]
Next, the electrostatic adsorption mechanism will be described. In this embodiment, the electrostatic adsorption mechanism is composed of a substantially rectangular flat plate electrode, and is fitted into two substantially rectangular recesses formed on both ends of the lower surface of the pressure plate 27. Further, the surface of the plate electrode (the lower surface side of the pressure plate 27) is covered with a dielectric, and the main surface of the dielectric is provided so as to be flush with the lower surface of the pressure plate 27. In this way, the plate electrodes arranged on the pressure plate 27 are connected to positive and negative DC power sources via appropriate switches. For this reason, when a positive or negative voltage is applied to each plate electrode, a negative or positive charge is induced on the main surface of the dielectric. Then, the upper substrate 1 b is electrostatically adsorbed to the pressure plate 27 by the Coulomb force generated between the transparent electrode film formed on the upper substrate 1 b by the electric charge. Here, the voltage applied to each plate electrode may be the same polarity, or may be a different bipolar.
[0025]
In addition, when the circumference | surroundings is air | atmosphere, it is better to perform attraction | suction adsorption by the suction hole mentioned above. The reason for this is that when electrostatic adsorption is performed, if there is an air layer between the upper substrate 1b and the pressure plate 27, a discharge phenomenon due to static electricity occurs and the upper substrate 1b and the pressure plate 27 are damaged. For this reason, for example, when the upper substrate 1b is first tightly held on the pressure plate 27, the surroundings are in the atmosphere. Therefore, the upper substrate 1b is first adsorbed by the suction adsorption mechanism, and the inside of the decompression chamber is depressurized so that no discharge phenomenon occurs. It is desirable to perform electrostatic adsorption after the pressure has been reduced to a low pressure.
[0026]
Here, as will be described later, if the pressure in the decompression chamber is reduced while the upper substrate 1b is sucked and sucked by the pressure plate 27, the suction force is reduced and the upper substrate 1b may fall. Therefore, the upper chamber unit 21 is provided with a receiving claw 60 for receiving the upper substrate 1b at a position slightly below the pressure plate 27. As shown in FIG. 2, the receiving pawls 60 are disposed corresponding to two corners which are diagonal positions of the upper substrate 1b, and a shaft 59 extending downward from the upper chamber unit 21. Is held down.
[0027]
Specifically, although not shown, a shaft 59 is inserted into a through-hole formed in the upper chamber unit 21, and the shaft 59 is configured to rotate about its axis and move up and down. In this case, a vacuum seal is provided on the shaft 59 so as not to cause a vacuum leak in the decompression chamber. The rotation is performed by a rotation actuator (not shown) connected to the end of the shaft 59, and the vertical movement is similarly performed by a lift actuator (not shown) connected to the end of the shaft 59. By rotating or vertically moving the shaft 59 in this way, the substrates 1a and 1b are bonded to each other, and the liquid crystal agent applied on the lower substrate 1a is expanded in the spreading direction of the main surfaces of the substrates 1a and 1b. In this case, the receiving claw 60 can be retracted so as not to get in the way.
[0028]
Next, the XYθ stage T1 will be described. The XYθ stage T1 includes an X stage 4a disposed on the gantry 2, a Y stage 4b disposed on the X stage 4a, a θ stage 4c disposed on the Y stage 4b, A table 9 disposed on the θ stage 4c and mounting and holding the lower substrate 1a, and a lower chamber unit fixed on the Y stage 4b via a plate 13 and having an upper opening that forms a decompression chamber together with the upper chamber unit 21 10 and.
[0029]
In the X stage 4a of the present embodiment, the drive motor 5 moves the Y stage 4b, θ stage 4c, table 9 and lower chamber unit 10 in the left-right direction (X-axis direction in FIG. 1), that is, the liquid crystal pattern coating unit S1 and the substrate It is comprised so that it can reciprocate below the bonding part S2. The Y stage 4b is configured to move the θ stage 4c, the table 9, and the lower chamber unit 10 in the front-rear direction (Y-axis direction in FIG. 1) by the drive motor 6. Furthermore, the θ stage 4 c is configured to rotate in the θ direction shown in FIG. 1 with respect to the Y stage 4 b by the drive motor 8 through the rotary bearing 7. Here, the θ stage 4c is rotatably attached to the lower chamber unit 10 via a rotary bearing 11 and a vacuum seal 12, so that even if the θ stage 4c rotates, the lower chamber unit 10 is pulled and rotated. It has a structure that does not.
[0030]
Here, since the lower substrate 1a is placed in the direction of gravity on the table 9, in order to position the lower substrate 1a, the table 9 is adjacent to the lower substrate 1a as shown in FIG. A positioning mechanism having a plurality of positioning members 81 respectively disposed corresponding to the two peripheral portions and a plurality of pressing rollers 82 respectively disposed corresponding to the remaining two peripheral portions of the lower substrate 1a. Provided. The pressing roller 82 is configured to move on the table 9 in the direction of the arrow shown in FIG. 2, for example. By pressing the lower substrate 1a against the positioning member 81 with each pressing roller 82, the lower substrate 1a is horizontally aligned. Positioning in the direction (surface direction of the table 9) and holding on the table 9 are performed.
[0031]
However, there is a possibility that the lower substrate 1a is displaced or lifted by the influence of the upper substrate 1b coming into contact with the sealing agent or the liquid crystal agent on the lower substrate 1a at the time of micropositioning immediately before the substrates 1a and 1b are bonded together. Alternatively, when the inside of the decompression chamber is decompressed, the air entering between the lower substrate 1a and the table 9 escapes during the decompression process, which may cause the lower substrate 1a to dance and shift. Therefore, even in the table 9, the suction suction mechanism and the electrostatic suction mechanism that are configured in the same manner as the pressure plate 27 described above are provided, and thereby the lower substrate 1 a is closely held on the table 9. .
[0032]
Here, the table 9 is provided with a plurality of pins (not shown) that can protrude from the mounting surface of the lower substrate 1a and are movable in the vertical direction. By providing the pins in this way, each pin can be raised to push up the substrate after bonding, thereby facilitating removal from the table 9. Further, for example, when the pins are raised, they are brought into contact with the table 9 to be in a grounded state, and the substrates after pasting can be discharged.
[0033]
Subsequently, the lower chamber unit 10 includes an O-ring 44 disposed at the upper end (periphery of the opening) and a ball bearing 87 disposed outside the O-ring 44. Since the O-ring 44 is provided in this way, when the upper chamber unit 21 is lowered and its flange 21a is brought into contact with the O-ring 44 as will be described later, the chamber units 10 and 21 are integrated to reduce the pressure. It can function as a chamber. Further, the ball bearing 87 is configured to be set at an arbitrary position in the vertical direction in order to adjust the collapse amount of the O-ring 44 when the decompression chamber is decompressed. By appropriately adjusting the position of the ball bearing 87 as described above, a large force applied by the decompression can be received by the lower chamber unit 10 via the ball bearing 87. Since the ball bearing 87 is provided, the O-ring 44 can be elastically deformed. Therefore, the XYθ stage T1 is easily finely moved within the elastic range of the O-ring 44 at the time of bonding, which will be described later. Can be positioned.
[0034]
Next, the operation of the liquid crystal substrate assembly apparatus of this embodiment will be described.
[0035]
First, after placing the jig holding the upper substrate 1b on the table 9 using a transfer machine hand (not shown), the drive motor 5 is driven to move the X stage 4a, and the XYθ stage T1 is moved to the substrate bonding portion. Move below S2. Then, the motor 40 is driven to lower the pressure plate 27, and the upper substrate 1 b on the table 9 is sucked and adsorbed to the pressure plate 27. Thereafter, the motor 40 is driven to raise the pressure plate 27, and the pressure plate 27 waits with the upper substrate 1b held.
[0036]
When the holding of the upper substrate 1b to the pressure plate 27 is completed, the drive motor 5 is driven to move the XYθ stage T1 below the liquid crystal pattern application unit S1. And the jig | tool which became empty from the table 9 is removed, the lower board | substrate 1a is mounted on the table 9 using the hand of a transfer machine, This positioning board | substrate 81 shown in FIG. It is positioned and held by the pressing roller 82.
[0037]
Here, normally, the upper substrate 1b and the lower substrate 1a are arranged so that the rubbing directions of the alignment films provided on the respective substrates 1a and 1b are substantially perpendicular, so that the liquid crystal agent is placed in a predetermined area (position). When supplying, it is necessary to consider the rubbing direction of each of the substrates 1a and 1b so that the liquid crystal agent can be spread at the time of bonding. That is, if the shape of the supplied liquid crystal agent is elongated in a direction substantially perpendicular to the alignment direction, the liquid crystal agent spreads substantially uniformly. The reason for applying the liquid crystal agent in consideration of the rubbing direction in this way is that the liquid crystal agent easily flows in the rubbing (alignment) direction, so the time until the liquid crystal agent reaches the sealant is substantially uniform regardless of the direction. This is because the liquid crystal agent spreads slowly so that it is close to the sealant. Therefore, in consideration of the spread of the liquid crystal agent at the time of bonding, a pattern is formed with a predetermined angle of inclination with respect to the orientation direction of the lower substrate 1a as will be described later. Make the spread substantially uniform.
[0038]
From the above, each substrate 1a, 1b has a table 9 so that the rubbing direction thereof has a predetermined angle with respect to the application direction of the liquid crystal agent (for example, the X-axis direction shown in FIG. 1 in this embodiment). Place on top.
[0039]
As described above, when the lower substrate 1a is held on the table 9, in order to improve the wettability of the liquid crystal agent on the surface of the lower substrate 1a, ion blowing is performed using the ion blowing means IB shown in FIG. . In this ion blow, ionized ultrasonic air is blown onto the surface of the lower substrate 1a to improve the cleaning of the substrate surface and the wettability of the liquid crystal agent. Here, instead of the ion blow, dry cleaning may be performed by a UV (ultraviolet) dry cleaner UVL shown in FIG. However, this dry cleaning is preferably performed before application of the sealant because it may adversely affect the sealant (solidify the sealant) if it is performed after application of the sealant described later. In the case of using ion blow, there is no problem even if it is performed after applying the sealant.
[0040]
Subsequently, the drive motors 5 and 6 are driven, and the X stage 4a and the Y stage 4b are moved to move the XYθ stage T1 in the X-axis and Y-axis directions, thereby sealing on the lower substrate 1a from the dispenser for supplying the sealant. The agent is discharged. At that time, a sealing agent is applied on the lower substrate 1a in a closed pattern (for example, a mouth shape). After applying the sealing agent in this way, a required amount of liquid crystal agent is applied from the dispenser 17 into the frame made of the sealing agent. Below, the application | coating method of the liquid crystal agent is explained in full detail.
[0041]
First, the above-described substrate surface height measuring device in which the height (discharging height of the liquid crystal agent P) of the nozzle tip 18b for applying the liquid crystal agent P to the lower substrate 1a is provided in the vicinity of the dispenser 17 for applying the liquid crystal agent. Measure using LS. Thereafter, the motor 16 is driven based on the measured value to move the Z-axis stage 15 up and down, and the nozzle tip 18b of the dispenser 17 is positioned at a predetermined height. In the present embodiment, the height of the nozzle tip 18b is set to about 10 to 20 μm, which is lower than the height of the sealing agent (in the present embodiment, about 20 to 30 μm). . Thus, by making the discharge height of the liquid crystal agent P lower than the height of the sealing agent, the reaction force acting between the substrates 1a and 1b by the liquid crystal agent P when the substrates are pressed when the substrates are bonded can be reduced. Can reduce the impact force when the liquid crystal agent is dropped as in the conventional example. As a result, the occurrence of color unevenness can be prevented. Furthermore, since the height of the supplied liquid crystal agent P is low, the bonding time can be shortened.
[0042]
Subsequently, while moving the X stage 4a and the Y stage 4b to move the lower substrate 1a in the X-axis and Y-axis directions, the liquid crystal agent P is discharged from the nozzle tip 18b to substantially the center of the main surface of the lower substrate 1a. Apply in a predetermined pattern near the area.
[0043]
As shown in FIG. 4A, the liquid crystal agent application pattern in this embodiment is obtained by applying the liquid crystal agent P linearly at the set height of the nozzle tip 18b described above in the pattern of the closed sealant. It is. In this case, the coating direction is applied at an angle θ (for example, about 30 to 60 degrees) with respect to the alignment direction R (rubbing direction) of the alignment film of the lower substrate 1a. Is an amount substantially equal to the volume between the substrates 1a and 1b and the sealant when the substrate bonding is completed. The application direction of the liquid crystal agent P is desirably 45 degrees with respect to the alignment direction if the liquid crystal agent P spreads when the substrates are bonded. Thus, the supply time of the liquid crystal agent P can be shortened by continuously discharging and applying the liquid crystal agent P to the lower substrate 1a.
[0044]
Here, before the liquid crystal agent P is discharged, only the inert gas is supplied in advance from the gas supply unit 18a to make the surface of the lower substrate 1a an inert gas atmosphere, and then the liquid crystal agent P and the inert gas are discharged simultaneously. It is desirable to apply the liquid crystal agent P. By applying the liquid crystal agent P in an inert gas atmosphere in this way, it is possible to prevent the inclusion of moisture and impurities in the atmosphere and the oxidation of the liquid crystal agent P. In addition, the liquid crystal agent P can be wetted and spread by the action of the discharged inert gas, and the height of the liquid crystal surface can be further reduced, so that the substrate bonding time can be further shortened. Moreover, the heater HT shown in FIG. 2 may be installed on the table 9, and the viscosity of the applied liquid crystal agent P may be lowered by warming the lower substrate 1a with the heater HT, thereby reducing the height of the liquid crystal surface.
[0045]
Here, after applying the liquid crystal agent P as described above, the surface of the lower substrate 1a may be ion blown again. As a result, the lower substrate 1a further improves the wettability of the liquid crystal agent, and can spread the liquid crystal agent to the end surface of the sealant faster than in the case where ion blowing is not performed. Further, when applying the liquid crystal agent P, the application may be performed while vibrating the lower substrate 1a. As a result, the impact force at the time of dropping the liquid crystal agent as in the conventional example can be further alleviated, and further, the surface tension between the liquid crystal agent and the lower substrate 1a can be easily eliminated, so that color unevenness is further generated. Can be prevented.
[0046]
Here, although explanation is omitted, spacers are spread or pasted on the upper substrate 1b or the lower substrate 1a in advance. The spacer in this case is to prevent the gap between the substrates 1a and 1b from becoming a predetermined amount or less when the substrates 1a and 1b are bonded together. The spacers may be mixed in the liquid crystal agent, and the spacers may be dispersed together with the liquid crystal application.
[0047]
As described above, after the required amount of liquid crystal agent is applied, the drive motor 5 is driven to move the XYθ stage T1 to a predetermined position below the substrate bonding portion S2. When the XYθ stage T1 stops, the cylinder 22 is operated to lower the upper chamber unit 21, and the flange portion 21a is brought into contact with the O-ring 44. Thereby, a decompression chamber composed of the lower chamber unit 10 and the upper chamber unit 21 is formed.
[0048]
After the decompression chamber is formed, the vacuum valve 23 is opened to decompress the interior of the decompression chamber. At this time, as described above, the upper substrate 1b is sucked and adsorbed by the pressure plate 27. Therefore, when the pressure in the decompression chamber is reduced and the pressure is reduced, the suction and adsorption force acting on the upper substrate 1b is gradually increased. The upper substrate 1b cannot be held because it becomes smaller, and the upper substrate 1b falls by its own weight. For this reason, the receiving claw 60 shown in FIG. 2 is moved by the rotary actuator or the lifting actuator described above, and the upper substrate 1b is received by the receiving claw 60 and held at a position slightly below the pressure plate 27.
[0049]
When the pressure in the decompression chamber is sufficiently reduced (in this embodiment, about 5 × 10^-3At about Torr), a voltage is applied to the electrostatic adsorption mechanism provided on the pressure plate 27, and the upper substrate 1b on the receiving claw 60 is held on the pressure plate 27 by Coulomb force. At that time, since the pressure in the decompression chamber has already been significantly reduced, and no air remains between the pressurizing plate 27 and the upper substrate 1b, discharge due to static electricity does not occur. Further, there is no dance of the upper substrate 1b that occurs when air escapes.
[0050]
When the upper substrate 1b is electrostatically attracted, the shaft 59 is lowered by the elevating actuator and rotated by the rotating actuator, and the receiving claw 60 is retracted so as not to obstruct the bonding of the substrates 1a and 1b. Then, the motor 40 is driven to lower the pressure plate 27 and bring the upper substrate 1b closer to the lower substrate 1a. Thereafter, an alignment mark provided on each of the substrates 1a and 1b is read using an image recognition camera, and the positional deviation is measured by image processing. Based on the measured values, the X stage 4a, the Y stage 4b and the θ stage 4c are measured. Operation control is performed to finely move the table 9, and the lower substrate 1a and the upper substrate 1b are aligned with high accuracy. Here, since the lower chamber unit 10 is provided with the ball bearing 87 as described above, the ball bearing 87 can maintain the interval between the chamber units 10 and 21 during the fine movement, and the O-ring 44 is extremely The vacuum state (depressurized state) can be maintained without being deformed.
[0051]
When the alignment is completed, the pressure plate 27 is further lowered, and the lower surface of the upper substrate 1b is brought into contact with the sealing agent on the lower substrate 1a. At that time, while controlling the driving force of the motor 40 while measuring the pressure applied to the sealant by the load meter 33, the substrates 1a and 1b are bonded to each other at a desired interval. In this case, since the upper substrate 1b is in close contact with the pressure plate 27 by the electrostatic adsorption force, the central portion thereof does not hang down. Therefore, the spacers in the liquid crystal agent are not adversely affected, and the alignment failure between the substrates 1a and 1b does not occur.
[0052]
Here, when the area of the substrate to be bonded becomes large, the sealing agent cannot be sufficiently crushed only by the above-described bonding with the applied pressure. For this reason, when the bonding (primary pressurization) by the applied pressure is completed, the electrostatic adsorption of the pressure plate 27 is released, the cylinder 22 is operated, and the upper chamber unit 21 is raised. Then, the vacuum valve 23 is closed and the gas purge valve 25 is opened, and nitrogen gas or clean dry air is supplied into the vacuum chamber to return to atmospheric pressure. By returning the inside of the vacuum chamber to atmospheric pressure in this way, pressure is applied to the surface of the liquid crystal substrate, and bonding is reliably performed to a desired thickness (secondary pressurization).
[0053]
Here, when the pressure in the vacuum chamber is changed from the vacuum state to the atmospheric pressure, the space between the liquid crystal agents between the substrates 1a and 1b is in a vacuum state, so that the substrates 1a and 1b are substantially uniform. A large pressure is applied from the outside. For example, if atmospheric pressure is applied when the space between the substrates 1a and 1b is in a vacuum state, a force of 121.6 kN can be applied. The main pressurization is performed by using the pressure applied to each of the substrates 1a and 1b.
[0054]
When the bonding is completed, the gas purge valve 25 is closed, the XYθ stage T1 is returned under the liquid crystal pattern coating unit S1, the substrate bonded from the table 9 is taken out by the hand of the transfer machine, and the next substrate is prepared for bonding. . The taken-out bonded substrate is sent to a downstream UV light irradiation device, a heating device, or the like to cure the sealing agent.
[0055]
As described above, in the present embodiment, since the sealant is applied and the liquid crystal agent is applied, the process can be shifted to the bonding process immediately, so that it is difficult for dust to adhere to the substrate before bonding. For this reason, it is difficult for a defective product due to a drop mark or the like as in the conventional example described above to occur on the substrate after bonding, and the yield in production can be improved.
[0056]
Further, since the liquid crystal agent can be supplied in an accurate amount, wasteful consumption of the liquid crystal agent can be eliminated, and there is no possibility that the liquid crystal agent overflows outside the sealant pattern and contaminates the substrate. In this case, since the contaminated substrate cleaning step is not necessary, the productivity can be further improved.
[0057]
Furthermore, since the XYθ stage T1 for placing and holding the lower substrate 1a can be used for transporting the upper substrate 1b to the upper chamber unit 21, it is not necessary to provide another mechanism for transporting the upper substrate 1b. Miniaturization can be achieved.
[0058]
In addition, this invention is not necessarily limited to the aspect of the said embodiment, You may implement as follows.
(1) In the present embodiment, the liquid crystal pattern application unit S1 and the substrate bonding unit S2 are arranged on the common mount 2, but one example of applying the sealant and the liquid crystal agent is shown. An apparatus may be provided and may be configured separately from an apparatus that performs bonding. Furthermore, the sealing agent application and the liquid crystal agent application may be configured separately.
(2) The upper substrate 1b is not mounted on the XYθ stage T1, but is directly transferred to the pressure plate 27 from the hand of the transfer machine used for mounting on the XYθ stage T1 in this embodiment, and is sucked and adsorbed. It's okay.
(3) In this embodiment, the method of locally supplying the inert gas from the nozzle is exemplified, but the entire assembly apparatus is disposed in a chamber of an inert gas atmosphere or disposed in a decompression chamber. The liquid crystal agent dropping atmosphere may be in an inert gas or a vacuum (depressurized) state.
(4) In the present embodiment, the case where the sealing agent is applied to the lower substrate 1a is illustrated, but may be applied to the upper substrate 1b. However, in this case, since a step of inverting the upper substrate 1b after applying the sealing agent to the upper substrate 1b is required, it is desirable to appropriately select which substrate the sealing agent is applied to.
[0059]
Here, the liquid crystal agent application pattern may be performed as follows instead of the above-described pattern shown in FIG.
[0060]
First, as shown in FIG. 4B, a plurality of linear patterns of the liquid crystal agent P shown in FIG. In this case, the application direction of the liquid crystal agent P is applied at an angle θ with respect to the rubbing direction (alignment direction) R as in the liquid crystal agent application pattern shown in FIG. By adopting such a liquid crystal agent application pattern, a sufficient amount of the liquid crystal agent P can be supplied to the lower substrate 1a even if the distance between the nozzle tip 18b and the lower substrate 1a is reduced. As a result, the height of the liquid crystal agent P can be further reduced, so that the above-described color unevenness can be prevented and the bonding time can be shortened. In this case, it is desirable that the substrate bonding is performed after the plurality of applied liquid crystal agents P are spread and adhered in the pattern of the sealing agent.
[0061]
Second, as shown in FIG. 4C, the liquid crystal agent P is applied in a substantially cross shape. The reason for applying in a substantially cross shape in this way is that the rubbing direction R is substantially perpendicular to the upper substrate 1b and the lower substrate 1a, so that the liquid crystal agent P can be easily spread when the substrates are bonded together. In such a liquid crystal agent application pattern, as shown in FIG. 4C, even if the rubbing direction (alignment direction) R and the application direction of the liquid crystal agent P coincide with each other, the liquid crystal agent P easily spreads. This is effective when the liquid crystal agent P is applied in the direction that coincides with.
[0062]
Third, as shown in FIG. 4D, the liquid crystal agent P is applied in a wide, substantially linear shape (substantially rectangular shape). In this case, instead of the nozzle tip portion 18b of the substantially circular discharge port described above, a nozzle tip portion having a porous serial discharge port in which a plurality of liquid crystal agent discharge holes are arranged in series is used. The application direction of the liquid crystal agent P at that time is applied at an angle θ with respect to the rubbing direction (alignment direction) R in the same manner as the liquid crystal agent application pattern shown in FIG. By applying the liquid crystal agent P using such a nozzle tip, in order to supply a desired amount of the liquid crystal agent P, it is necessary to change the discharge position a plurality of times as shown in FIG. The supply time of the liquid crystal agent P can be shortened. Further, even if the distance between the nozzle tip 18b and the lower substrate 1a is reduced, a sufficient amount of the liquid crystal agent P can be supplied to the lower substrate 1a, so that the height of the liquid crystal agent P can be further reduced. Further, the above-described color unevenness can be prevented and the bonding time can be shortened.
[0063]
【The invention's effect】
The method and apparatus for assembling a liquid crystal substrate according to the present invention includes an intermolecular force generated between a substrate film surface and a liquid crystal agent generated by dropping a liquid crystal agent on the substrate in the prior art, and a drop impact. Further, it is possible to prevent the occurrence of color unevenness due to deformation or breakage of the film surface caused by the reaction force of the liquid crystal agent accompanying pressurization during bonding. In addition, it is possible to prevent the occurrence of the interface of the dropped liquid crystal agent in a narrow gap state between the upper and lower substrates during the bonding process, and it is possible to prevent the occurrence of color unevenness. Furthermore, since it is possible to prevent moisture, impurities, etc. in the air at the time of supplying the liquid crystal agent that has caused a drop mark due to an oxidation phenomenon or the like, it is possible to prevent color unevenness caused by the drop mark. It is possible to obtain an excellent method for assembling a liquid crystal substrate and an apparatus for assembling the same.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view showing a configuration of an embodiment of an apparatus for assembling a liquid crystal substrate according to the present invention.
FIG. 2 is a perspective view illustrating a receiving claw for an upper substrate and a positioning mechanism for a lower substrate according to the present embodiment.
FIG. 3 is an explanatory diagram illustrating a configuration of a nozzle portion of a liquid crystal agent supply dispenser according to the present embodiment.
4A and 4B are top views of the liquid crystal agent application pattern as viewed from above the lower substrate, in which FIG. 4A shows a substantially linear pattern, and FIG. 4B shows the abbreviated pattern shown in FIG. FIG. 4 (c) is an explanatory diagram for explaining a substantially cross-shaped pattern, and FIG. 4 (d) is an explanatory diagram for explaining a wide substantially linear pattern in which a plurality of linear patterns are provided.
[Explanation of symbols]
1a Lower substrate (the other substrate)
1b Upper substrate (one substrate)
9 tables
17 Dispenser (liquid crystal supply means)
18 nozzles
18a Gas supply unit
18b Nozzle tip
27 Pressure plate
P Liquid crystal agent
R rubbing direction (orientation direction)
θ angle
T1 XYθ stage (drive means)
LS Substrate surface height measuring instrument
IB ion blow means
UVL UV dry cleaner

Claims (4)

One of the two substrates to be bonded is held on the lower surface of the pressure plate and the other substrate coated with the sealing agent in a closed pattern is held on the table, and the other substrate is placed on the other substrate. A method of assembling a liquid crystal substrate after supplying a liquid crystal agent and bonding each of the opposed substrates with the sealant applied to the other substrate with each interval narrowed,
A nozzle positioning step of positioning a nozzle tip for discharging a liquid crystal agent at a predetermined height with respect to the surface of the other substrate above the other substrate;
On the other substrate, at least a predetermined angle of the liquid crystal agent is set at a predetermined angle with respect to the alignment direction of the other substrate so that the slower spreading speed of the liquid crystal agent is closer to the sealing agent. have a liquid crystal coating step of coating a single substantially linear coating pattern,
The liquid crystal coating step supplies the inert gas to the nozzle tip around prior to application of the liquid crystal material, and a feature to make a coating of the liquid crystal material while discharging the liquid material and an inert gas at the same time Method of assembling a liquid crystal substrate. 2. The method of assembling a liquid crystal substrate according to claim 1, wherein the surface of the other substrate is subjected to UV dry cleaning or ion blow cleaning before the liquid crystal agent coating step. A pressure plate for holding one of the two substrates to be bonded, and the other substrate to which the sealant is applied in a closed pattern among the substrates, and holding the other substrate A table capable of being arranged opposite to the one substrate; and a liquid crystal supply means for supplying a liquid crystal agent onto the other substrate, and the one substrate and the other substrate supplied with the liquid crystal agent are added in a decompression chamber. An apparatus for assembling a liquid crystal substrate for pressure bonding,
A nozzle provided in the liquid crystal supply means for discharging a liquid crystal agent onto the other substrate;
A measuring instrument for measuring the distance between the surface of the other substrate and the nozzle;
For applying the liquid crystal agent substantially linearly at a predetermined angle with respect to the orientation direction of the other substrate, so that the slower spreading speed of the liquid crystal agent is close to the sealing agent at the nozzle. Drive means for energizing the movement of the table;
The nozzle is provided with an inert gas supply port that discharges an inert gas before application of the liquid crystal agent and surrounds the liquid crystal agent discharge port of the nozzle that discharges the inert gas simultaneously with the application of the liquid crystal agent. A liquid crystal substrate assembly apparatus characterized by the above. 4. The liquid crystal substrate assembly apparatus according to claim 3 , wherein the liquid crystal agent discharge port of the nozzle is formed in a porous series shape for applying the liquid crystal agent in a substantially straight line having a predetermined width.

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