JPH0921988A - Method for sticking liquid crystal cell and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To embody sticking of liquid crystal cells with simple and inexpensive mechanisms without adopting a pressurization system utilizing compressed air, etc. SOLUTION: The device 1 for sticking the liquid crystal cells forms a hermetic seal by placing glass plates 6, 7 superposed on a moving stage 2 of a square frame shape, lowering a clamping frame 8 mounted with the flexible hermetic sheet 9 existing right above these plates and pressing a press frame 83 on the rear surface thereof onto a square sealing frame 24 on the outer side of the front surface of the stage. The hermetic space 40 communicating only to the spacing between the glass plates 6 and 7 is put into a reduced pressure state when an evacuating means 27 is driven thereafter, by which the glass plate 7 side is pressed directly and the glass plate 6 side is pressed from above the sheet 9 by the atm. pressure. The glass plates 6, 7 are pressed without adopting the pressurizing system in such a manner and the sticking of the plates is executed in the state of forming the uniform spacing therebetween.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing technique of a liquid crystal cell constituting a liquid crystal display panel, and particularly, in a state where a spacer is sandwiched in order to form a constant gap for enclosing a liquid crystal, The present invention relates to a method and apparatus for laminating liquid crystal cells, which are obtained by laminating and pressing together a plurality of plates.

[0002]

2. Description of the Related Art The cell structure of a liquid crystal display panel is
Two glass plates are overlapped with each other with a space sphere sandwiched therebetween, and a gap for enclosing the liquid crystal is formed between them.

Further, in order to bond these glass plates to each other, a sealant is previously applied between them,
This sealing agent is cured while being pressed after stacking glass plates. Thermosetting sealant,
And those which are UV curable are generally known.

An apparatus for adhering two glass plates to each other to manufacture such a liquid crystal cell is to place two glass plates, which have been accurately overlapped with each other through an alignment process, on a stage, and to apply air pressure from above. In addition to pressing the glass plates and heating the glass plates from the outside or irradiating the glass plates with ultraviolet rays, the sealant between the glass plates is hardened to bond the glass plates together.

For example, the applicant of the present invention is disclosed in Japanese Patent Laid-Open No. 6-33742.
No. 9 proposes such a press device. The apparatus disclosed in this publication has a configuration in which two superimposed glass plates are pressed by compressed air from both sides, and uniform compression is performed from both sides of the glass plates without being affected by the smoothness of the stage surface and the like. It is possible to add power.

[0006]

Here, such a commonly used pressurizing type bonding apparatus requires a large-scale mechanism for generating a pressing force, and the manufacturing cost tends to be high. There is.

An object of the present invention is to adopt a pressurizing method,
An object of the present invention is to propose a liquid crystal cell bonding method and device which have a simple structure and are inexpensive, and which are capable of accurately bonding glass plates.

[0008]

In order to solve the above-mentioned problems, according to the present invention, in order to form a constant gap for enclosing a liquid crystal, two plates are superposed on each other with a spacer interposed therebetween. The present invention relates to a method of bonding liquid crystal cells which are pressed and bonded together, and the bonding is performed through the following steps. First, the two plates are stacked with the sealant and the spacer sandwiched therebetween. Next, a frame-shaped hermetically closed space that communicates only with the gap between the two plates is formed around the two stacked plates. After this, the closed space is depressurized to a depressurized state sufficiently lower than the atmospheric pressure, so that the two plates are pressed against each other. Further, in parallel with the progress of the pressing operation, or after the two plates have reached a predetermined pressing state, the sealing agent is hardened to bond the two plates to each other.

Here, when a thermosetting sealant is used as the sealant, the heating step for curing the sealant is performed after the two plates are brought into a predetermined compressed state by the pressing operation. It is preferable to carry out.

Next, the present invention relates to a device for laminating liquid crystal cells in which two plates are superposed and pressed against each other with spacers sandwiched therebetween in order to form a constant gap for enclosing a liquid crystal. It has the following configuration. That is, a frame-shaped stage on which two plates are placed with a spacer and a sealing agent sandwiched therebetween, and a frame-shaped clamp member supported so as to be able to move up and down between a position in close contact with the stage and a position apart from the stage. A flexible airtight sheet whose outer peripheral edge is attached in an airtight state to the frame-shaped surface of the clamp member facing the stage, and the clamp member is lowered to a position in close contact with the stage. And a frame-shaped airtight seal formed between the clamp member and the contact surface of the stage in the above state, and the stage, the clamp member, the airtight sheet, and the two stacked sheets in the state where the airtight seal is formed. And a decompression unit that forms a predetermined decompressed state by evacuating the space defined by the plate.

In the apparatus of the present invention, further, in order to cure the thermosetting sealant sandwiched between the two plates, a stage moving mechanism for moving the stage to a decompression position and a heating position, It is desirable to have a configuration including a heating mechanism arranged at the heating position.

In the method and apparatus of the present invention, a closed space which communicates only with these gaps is formed around the two stacked plates, and the closed space is evacuated. As a result, the gap between the two plates is in a reduced pressure state and the atmospheric pressure acts from both sides, so that the two plates are pressed from both sides.
In the pressed state, the sealant between the two plates is hardened to perform the bonding. As described above, since the two plates are pressed and bonded together by utilizing the atmospheric pressure, the device configuration is simpler and the cost can be reduced as compared with the conventional method in which the two plates are pressed from both sides. . Moreover, since uniform pressure acts on both sides of the two glass plates, accurate bonding is performed.

Further, when a thermosetting sealant is used as the sealant, if the heat curing is performed in parallel with the step of pressing the two glass plates, the sealant will be foamed, which is appropriate. No good seal is formed. However, in the method and apparatus of the present invention, after the pressing step (vacuum evacuation) is completed, the sealing agent is heated and hardened while maintaining that state, so that such an adverse effect does not occur.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic structure of a liquid crystal cell laminating apparatus to which the present invention is applied. As shown in this figure, the laminating apparatus 1 of the present example is provided with a movable stage 2, and this stage 2 is arranged along a guide rail 3 at a decompression station 4 located on the right side in the figure and on the left side in the figure. It is possible to move back and forth between the heating stations 5 located. As the moving mechanism of the stage 2, various commonly used moving mechanisms can be adopted.

The two glass plates 6 and 7 to be bonded together in the apparatus of this embodiment are, for example, rectangular with one side of 300 to 500 mm and have a plate thickness of about 1.1 mm. A sealant (not shown) made of a thermosetting resin, for example, a thermosetting resin such as an epoxy resin is printed on one surface of these glass plates by a method such as screen printing. Then, spacer spheres (not shown) having a diameter of about 5 microns are sprinkled on the opposite surfaces of the glass plates, and then, after an alignment process, the two glass plates 6 and 7 are accurately overlapped. The glass plates 6 and 7 thus stacked are placed on the stage 2 with the glass plate 7 side facing down.

The stage 2 has a rectangular frame shape as a whole, and a rectangular opening 21 which is slightly smaller than the glass plates 6 and 7 to be installed is formed in the center thereof. Further, a rectangular seal frame 22 made of silicon sponge having a constant width and thickness is attached along the entire circumference of the inner peripheral edge of the surface of the stage 2 defining the periphery of the rectangular opening 21.

Further, at a position on the outer peripheral side of the frame-shaped upper surface 23 of the stage 2, a silicon sponge rectangular seal frame 24 having a size larger than the silicon sponge rectangular seal frame 22 is attached. . The lower half of the rectangular seal frame 24 is embedded in the stage 2, and the upper half of the rectangular seal frame 24 projects upward from the stage upper surface 23. The stage 2 has a communication hole 25 in the vertical direction.
Through, and its upper end opening 25a is located between these rectangular seal frames 22 and 24. A lower end opening 25b of the communication hole 25 is connected to a vacuuming mechanism 27 such as a vacuum pump via a flexible communication tube 26.

Immediately above the frame-shaped stage 2 of this construction,
A rectangular clamp frame 8 having substantially the same size and shape as this is located. The clamp frame 8 is supported by an elevating mechanism 81 composed of an air cylinder or the like. The elevating mechanism 81 moves up and down between a position shown in the figure and a position in close contact with the stage upper surface 24. There is. The lifting mechanism 81 is wholly supported on the stage 2 side by a support mechanism (not shown).
And moves horizontally along the guide rail 3 together with.
A pressing frame 83 protruding downward is formed on the outer peripheral edge of the lower surface 82 of the clamp frame 8. When the clamp frame 8 descends, the pressing frame 83 comes into contact with the square seal frame 24 on the outer side of the upper surface of the stage and is brought into close contact therewith to form an airtight seal.

A rectangular flexible airtight sheet 9 is attached to the lower surface 82 of the clamp frame 8. The outer periphery of the airtight sheet 9 is adhesively fixed to the clamp lower surface 82 in an airtight state.

Here, on the heating station 5 side, an upper heating mechanism 11 and a lower heating mechanism 12 are arranged above and below the stop position of the stage 2 which has moved to this position.

The upper heating mechanism 11 includes an elevating mechanism 13 and an upper heating plate 14 which is moved up and down by the elevating mechanism 13. Similarly, the lower heating mechanism 12 is an elevating mechanism 15 and a lower heating plate 1 which is moved up and down by the elevating mechanism 15.
6 is provided. The upper heating plate 14 includes a silicon sponge plate 141 forming a glass plate pressing surface and a heating plate 142.
The heater 143 and the heat insulating plate 144 are laminated from the lower side to the upper side. On the contrary, the lower heating plate 16 includes a silicon sponge plate 161, which forms a glass plate pressing surface, a heating plate 162, a heater 163, and a heat insulating plate 1.
It has a structure in which 64 is laminated from the upper side to the lower side.

The operation of the laminating apparatus 1 of this example having the above structure will be described. First, as shown in FIG. 1, in the depressurization station 4, two glass plates 6 and 7 which are superposed through an alignment process are placed on the stage 2. In this state, the outer peripheral edge portion of the lower glass plate 7 has a rectangular seal frame 22 inside the upper surface of the stage.
On top of.

In this state, the elevating mechanism 81 is driven to lower the rectangular clamp frame 8 from the retracted position shown in FIG.
As shown in FIG. 2, it is lowered to the clamp position where it hits the upper surface 23 of the stage. As shown in FIG. 2, in this clamped state, the pressing frame 83 on the lower surface of the clamp frame 8 is
Is pressed against the rectangular seal frame 24 on the outside of the upper surface of the stage with a predetermined pressure, and an airtight seal is formed therebetween. As a result, the stage 2, the clamp frame 8, the airtight sheet 9 attached thereto,
The glass plates 6 and 7 form a substantially closed space.

After the clamped state is formed, the vacuuming mechanism 27 is driven to shift the inside of the sealed space to the depressurized state via the communication hole 25. By performing evacuation, the flexible sheet 9 is in close contact with the surface of the upper glass 6, and a frame-shaped closed space 40 is formed so as to surround the outer peripheries of the glass plates 6 and 7. This state is enlarged and shown in FIG. The closed space 40 communicates only with the gap between the glass plates 6 and 7. Therefore, if vacuuming is further performed in this state, the sealed space 40 becomes sufficiently lower than the atmospheric pressure, and as a result, both sides of the two glass plates 6 and 7 are applied according to the formed differential pressure. It will be in a compressed state. Therefore, by appropriately reducing the pressure, the two glass plates 6,
7 can be put into an appropriate compression state.

After the target compressed state is formed, the stage 2 is horizontally moved toward the heating station 5 by the stage moving mechanism while maintaining the state, and the stage 2 is stopped at the heating station 5. Let This state is shown in FIG.

Next, the upper and lower heating plates 12 and 14 are respectively lowered and raised to bring them into contact with the surfaces of the glass plates 6 and 7. This state is shown in FIG.

After that, the heating plates 12 and 14 are held at that position, and heating is performed for a predetermined time. By this heating, the thermosetting sealant between the glass plates 6 and 7 is cured, and the two glass plates 6 and 7 are bonded together.
Through the above steps, the glass plates 6 and 7 for liquid crystal cells are bonded.

As described above, in the apparatus of this embodiment, the clamp frame only contacts the rectangular seal frame on the upper surface of the stage to form an airtight seal, and does not press two glass plates. Therefore, only the atmospheric pressure due to evacuation acts on the glass plates, and the two glass plates can be bonded together with a uniform gap formed.

FIG. 4 shows a modified example of the apparatus of this example. In the example shown in FIG. 4A, the rectangular seal frame 100 on the clamp frame 8 side and the rectangular seal frame 2 on the stage 2 side are shown.
2, the outer periphery of the glass plates 6 and 7 is clamped. In this way, the periphery of the glass plates 6 and 7 may be clamped in advance. However, if this clamping force is too large, the spacer balls between the glass plates serve as fulcrums, causing warpage in the glass plates, which may deteriorate the gap accuracy. Such an adverse effect does not occur in the case of the embodiment shown in FIGS. 1 to 3 described above.

The example shown in FIG. 4B is an example in which the sheet 9 is omitted. In this case, since the glass plates 6 and 7 are sandwiched and the hermeticity is ensured by the stage 2 and the clamp frame 8, the clamping force needs to be a certain value or more. Therefore, the glass plates 6 and 7 may be warped or the like, which is suitable for manufacturing a liquid crystal cell that does not require so much gap accuracy.

In the above embodiment, a thermosetting material is used as the sealant placed between the glass plates 6 and 7. However, the present invention can also be applied to the case where, for example, an ultraviolet curable sealant is used. In this case, an ultraviolet irradiation lamp or the like may be installed instead of the heating plate.

[0033]

As described above, in the liquid crystal cell laminating method and device of the present invention, a hermetically sealed space is formed around two superposed glass plates, which communicates only with their gaps. The glass plates are pressed and bonded together by utilizing the difference from the atmospheric pressure formed by drawing a vacuum in this space. Therefore, as compared with the conventional pressurizing method in which compressed air or the like is used to compress the glass plate from both sides, the device configuration is simpler and the manufacturing cost can be reduced.

In the present invention, when a thermosetting sealant is used as the sealant, the glass plate is subjected to a pressing step (depressurizing step) and then heat curing. Therefore, it is possible to avoid the adverse effect that the sealant foams at the time of heat curing and a proper seal cannot be formed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a liquid crystal cell bonding apparatus according to an embodiment of the present invention.

2A and 2B are diagrams showing the operation of the apparatus of FIG. 1, in which FIG. 2A is an explanatory view showing a state in which a glass plate is placed on a stage, and FIG.
FIG. 6 is an explanatory diagram showing a clamped state.

3A and 3B are diagrams showing an operation of the apparatus of FIG. 1, FIG. 3A is an explanatory view showing a state in which a stage is moved to a heating station, and FIG. 3B is an explanatory view showing a heating state.

FIG. 4 is a partial cross-sectional view showing a modified example of the device of FIG.

[Explanation of symbols]

 1 Liquid Crystal Cell Bonding Device 2 Moving Stage 22 Rectangular Seal Frame 23 Stage Top 24 Rectangular Seal Frame 25 Communication Hole 26 Communication Tube 27 Vacuuming Mechanism 3 Guide Rail 4 Decompression Station 40 Sealed Space 5 Heating Station 6, 7 Glass Plate 8 Clamp Frame 81 Lifting mechanism 83 Holding frame 9 Flexible airtight sheet 11, 12 Heating mechanism

Claims (4)

[Claims] 1. A method for laminating liquid crystal cells, in which two plates are stacked and pressed against each other in a state that a spacer is sandwiched in order to form a constant gap for enclosing a liquid crystal, a sealing agent and a spacer. The two plates are overlapped with the plate sandwiched between them, and a frame-like enclosed space that communicates only with the gap between these plates is formed around the two overlapped plates. By making the decompression state sufficiently lower than atmospheric pressure, the two plates are pressed against each other, and in parallel with the progress of the pressing operation, or after the two plates have reached a predetermined pressing state, A method for laminating a liquid crystal cell, which comprises curing these sealing agents and laminating these two plates together. 2. The sealant according to claim 1, wherein the sealant is a thermosetting sealant, and in the heating step for curing the sealant, the pressing operation brings the two plates into a predetermined compressed state. A method for laminating liquid crystal cells, which is performed after 3. A spacer and a sealant in a liquid crystal cell laminating apparatus in which two plates are stacked and pressed against each other in a state that a spacer is sandwiched in order to form a constant gap for enclosing a liquid crystal. Stacked with sandwiching 2
A frame-shaped stage on which a single plate is placed, a frame-shaped clamp member supported so as to be able to move up and down between a position in close contact with the stage and a position apart from the stage, and a frame-shaped side of the clamp member facing the stage. A flexible airtight sheet whose outer peripheral edge is attached to the surface in an airtight state, and between the clamp member and the contact surface of the stage in a state where the clamp member is lowered to a position in which the clamp member is in close contact with the stage. A frame-shaped airtight seal to be formed, and in a state in which the airtight seal is formed, a space demarcated by the stage, the clamp member, the airtight sheet, and the two stacked plates is evacuated to a predetermined decompression. A device for laminating a liquid crystal cell, comprising: a decompression means for forming a state. 4. The stage moving mechanism for moving the stage to a decompression position and a heating position according to claim 3, and for curing the thermosetting sealant sandwiched between the two plates. A liquid crystal cell laminating apparatus comprising: a heating mechanism arranged at the heating position.