JPH06160828A - Method for sticking flat plate - Google Patents

Abstract

PURPOSE:To rapidly and efficiently stick two sheets of flat plates in a state of keeping a uniform spacing without mis-registration. CONSTITUTION:A thermosetting resin 13 is applied to the stuck surface of the glass substrate 11 of a pair of the glass substrates 11, 12 to an open curvilinear shape having an injection port 19. Further, a closed curvilinear thermosetting resin 18 is formed on the outer side of the open curvilinear thermosetting resin 13. Plastic beads 14 are sprayed on the stuck surface of the glass substrate 12. After the two glass substrates 11, 12 are aligned under a reduced pressure, the glass substrate 11 and the glass substrate 12 are brought near to each other to bring the thermosetting resins 13, 18 into contact with each other over the entire surface. The atm. pressure is thereafter restored in the outside and the two glass substrates 11, 12 are pressurized by the difference between the closed space 20 enclosed by the thermosetting resin 18 and the two glass substrates 11, 12 and the atm. pressure. The glass substrates 11, 12 are then heated to cure the thermosetting resins, by which the sticking is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for laminating flat plates with a constant distance and without misalignment, and particularly to TN (twisted nematic) type and STN (super twisted nematic).
The present invention relates to a method for laminating two flat plates such as glass, which form a liquid crystal panel of shape, ferroelectricity, etc., a color filter laminating type CCD (charge coupled device) and the like.

[0002]

2. Description of the Related Art Conventionally, when two glass substrates for forming a liquid crystal panel or the like are bonded together, as shown in FIG. The resin 3 is applied in an open curve shape having an injection port 9 for injecting liquid crystal by a screen printing method or a drawing method using a dispenser or the like, and a uniform size interval is applied to the entire surface to be the bonding surface of the other glass substrate 2. After spraying the holding member 4, the two glass substrates 1 and 2 are superposed and aligned as shown in FIG. 11, and pressed by a pressing machine from above and below as shown in FIG. 12 at a high temperature of about 180 ° C. The two glass substrates 1 and 2 are bonded together by a pressure press method of pressing the plates 6 and 7 to cure the thermosetting resin 3.

The method using such a thermosetting resin requires a mechanism for aligning the positions of two glass substrates and a mechanism for pressing in a high temperature and high pressure state. The panel requires alignment accuracy within 3 μm in the horizontal direction and within 0.3 μm in the spacing, and the pressing pressure is 300N × 400mm. In addition, it must be pressed at a high temperature and high pressure with a uniform pressing force on the entire surface.

Since it is not possible to equip all of these mechanisms in one device, the glass substrate is aligned and
A device having a mechanism for pressing at room temperature and a device for pressing at high temperature are separately used.

However, if the front and back parallelism of the glass substrates 1 and 2 to be laminated is not ensured (if there is a difference in thickness), even if pressure is applied by the pressure plates 6 and 7 having parallel pressure surfaces. The pressure is not uniformly applied, but is strongly applied to the thick portions of the glass substrates 1 and 2, and the intervals between the glass substrates 1 and 2 are not constant. Further, in the case of stacking two sets of glass substrates one by one in order to improve the production efficiency, the unevenness of the thickness of the glass substrates 1 and 2 is accumulated to further increase the imbalance of the pressurization. Occurs.

Further, in the case of forming a liquid crystal panel, liquid crystal is sealed between two glass substrates, so if the distance is not constant, the reliability and quality of the product are greatly affected. Further, when the positions of the two glass substrates are deviated, the quality is also greatly affected.

Therefore, as shown in FIG. 13, the flexible rubber film 10 and the holding plate 8 are prepared to be bonded to each other.
A vacuum press method is used in which the glass substrates 1 and 2 are placed, the space formed by the rubber film 10 and the holding plate 8 is depressurized, and pressure is applied through the flexible rubber film 10 due to the difference in atmospheric pressure. 2
A device is used that applies pressure so that the distance between the glass substrates 1 and 2 is uniform.

[0008]

However, in this apparatus, the flexible rubber film 1 that can withstand a temperature of about 180 ° C. is used.
Since 0 cannot be obtained, the thermosetting resin 3 cannot be used as an adhesive, and therefore a two-component mixed type epoxy resin or the like must be used. Therefore, it is necessary to strictly control the time after mixing. There's a problem.

Another adhesive used in this vacuum pressing method is an ultraviolet curable resin, which is a material of the flexible rubber film 10 that sufficiently transmits ultraviolet rays and is not deteriorated by irradiation with ultraviolet rays for a long time. There is a problem that the material has to be selected.

In the above vacuum pressing method, the pressure difference generated by sucking the space formed by the rubber film 10 and the holding plate 8 to bring the rubber film 10 into close contact with the holding plate 8 and further sucking Since the pressure is applied at 1, the suction must be continued until the adhesive hardens, and it takes a long time to complete the bonding, and there is a problem that the manufacturing efficiency is not good.

Further, in both the pressure pressing method and the vacuum pressing method, as shown in FIG. 11, since the injection port 9 is narrowly limited, after bonding the two glass substrates 1 and 2 with the adhesive 3. , In the process of spreading the adhesive,
Since the air remaining inside can be discharged to the outside only through this inlet 9, the internal pressure temporarily rises, and due to this, a reaction force is generated against the external pressure, and the applied pressure is increased. However, there is a problem in that it causes the imbalance of the two, the displacement of the two glass substrates, and the like.

An object of the present invention is to provide a flat plate laminating method capable of efficiently laminating two flat plates in a short period of time without any misalignment while maintaining a uniform interval.

[0013]

SUMMARY OF THE INVENTION The present invention is a method for laminating a pair of flat plates facing each other while keeping a constant interval, and an adhesive is applied to the laminating surface of one of the pair of flat plates in the form of an open curve. On the outer surface of the one flat plate and the other flat plate with a plurality of spacing members are spread over the entire surface, and then both flat plates under reduced pressure. Overlap, then return the outside to atmospheric pressure,
It is a method for laminating flat plates, which is characterized in that the flat plates are pasted together by using a pressure difference between the inside of a closed space surrounded by the adhesive and the outside.

[0014]

According to the present invention, of the pair of flat plates facing each other,
On the other hand, an adhesive is applied in an open curve shape on the bonding surface of the flat plate, and an adhesive is applied in a closed curve shape on the outside thereof, and a large number of spaces are applied to the entire bonding surface of either one of the one flat plate and the other flat plate. The holding member is sprinkled. After aligning such a pair of flat plates under reduced pressure, they are overlapped with each other to form a closed space surrounded by both flat plates and the adhesive applied in the shape of a closed curve.
After that, the surroundings are returned to atmospheric pressure, and the flat plates are brought into close contact with each other due to the pressure difference between the closed space and the outside, and then heated to cure the adhesive to complete the bonding of the flat plates. Therefore, the two flat plates can be bonded to each other at a uniform interval in a short time without causing positional deviation.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view before laminating two glass substrates 11 and 12 in an embodiment of the present invention, and FIGS. 2 to 4 are sectional views for explaining a laminating process. is there. One glass substrate 1 of the pair of glass substrates 11 and 12
The thermosetting resin 13 is applied to the bonding surface of No. 1 by, for example, a screen printing method in an open curved shape having an injection port 19. Further, the thermosetting resin 18 is applied in a closed curve on the outside of the open curving thermosetting resin 13. Resin 1
The size of 3,18 is, for example, 1 mm in width and 100 μ in height.
m, and the open-curve thermosetting resin 13 is approximately 180 m
The closed-curve thermosetting resin 18 is applied in a rectangular area of 200 mm × 300 mm in a rectangular area of m × 280 mm.

Further, these thermosetting resins 13, 18
Spherical glass fibers 15 having a diameter of 10 μm, for example, are dispersed and mixed therein as a spacing member. On the other surface of the other glass substrate 12, as a space holding member, for example, plastic beads 1 having a diameter of 10 μm are used.
4 is evenly spread over the entire surface. Thermosetting resin 13, 18
The application and the spraying of the plastic beads 14 may be performed on different glass substrates as in this embodiment, or may be performed on the same glass substrate.

Both glass substrates 11, prepared as described above,
2, a pair of upper and lower plate-like holding plates 16 as shown in FIG.
It is held by a holding mechanism having 17. Around it 1
After reducing the pressure to about 10 ³ Pa and making it into a vacuum state, the space between both glass substrates 11 and 12 is kept at about 1 mm, and the thermosetting resins 13 and 18 are aligned without being in contact with each other. To do. Next, as shown in FIG. 3, the glass substrate 11 and the glass substrate 12 are brought close to each other, and the thermosetting resin 13, 1
8 in contact with the entire surface, and the thermosetting resin 18 and both glass substrates 1
A closed space 20 surrounded by 1 and 12 is formed.

Next, the circumference of both glass substrates 11 and 12 is returned to atmospheric pressure, and the holding plates 16 and 17 are removed. In this state, the difference between the atmospheric pressure in the closed space 20 and the atmospheric pressure causes both glass substrates 11,
12 is pressurized. At this time, the pressure acting between the glass substrates 11 and 12 is about 6000 N, and the thermosetting resins 13 and 18 under this pressure cause the glass fibers 15 and the plastic beads, which are the spacing members, to move as shown in FIG. It is extended to a height (diameter) of 14 μm and temporarily bonded. As a result, the volume of the closed space 20 becomes about 1/10 and the pressure becomes about 10 times 10 ⁴ Pa, which is sufficiently lower than the atmospheric pressure (about 10 ⁵ Pa) and there is no problem.

Next, both glass substrates 11 and 1 which are temporarily bonded
2 is put in a furnace of, for example, 180 ° C., and this temperature is maintained for, for example, 2 hours to cure the thermosetting resins 13 and 18 to complete the bonding. Then, the thermosetting resin 13 having an open curve shape
The rectangular area portion coated with is left, and the portion coated with the thermosetting resin 18 having a closed curve shape is cut surface lines 21, 22, 2
It is cut at 3,24.

FIG. 5 shows the glass substrate 1 after the bonding.
1 and 12 are perspective views, and FIG. 6 is a glass substrate 11, 1 in which a portion to which a thermosetting resin 18 having a closed curve shape is applied is cut off.
It is a perspective view of FIG. After laminating is completed, the cut surface lines 21 and 2
2, 23 and 24 were cut between the open curve thermosetting resin 13 and the closed curve thermosetting resin 18 of both glass substrates 11 and 12, and the closed curve thermosetting resin 18 was applied. Remove the part.

In order to bond the two glass substrates 11 and 12 with a greater force, the two glass substrates 11 and 12 that have been in contact with each other under reduced pressure are returned to the atmospheric pressure, and then the chamber or the like is further removed. A larger pressing force can be obtained by placing the container in a pressure resistant container and increasing the atmospheric pressure in this container. Further, depending on the type of the adhesive, only the adhesion by pressure may be sufficient.

In this embodiment, the method of laminating the glass substrates 11 and 12 for the liquid crystal panel has been mainly described. Therefore, the thermosetting resin 1 applied by the screen printing method or the like.
The curves 3 and 18 may have any shape such as a circular shape or an elliptical shape as long as the thermosetting resin 18 is a closed curve and the thermosetting resin 13 is an open curve having an injection port 19.

Further, in this embodiment, the case where the pair of glass substrates 11 and 12 are bonded together as a flat plate has been described.
The flat plates to be bonded are not limited to glass substrates. Further, as shown in FIG. 7, one glass substrate 31 of the pair of glass substrates is used.
A plurality of open-curve thermosetting resins 33 each having an injection port 39 are applied to the bonding surface, and a closed-curve thermosetting resin 38 is applied to the outer periphery so as to include all of the thermosetting resins 33. After that, you may implement the above-mentioned bonding method.

FIG. 8 is a perspective view of the two glass substrates 41 and 42 before the bonding by another bonding method, and FIG.
It is a perspective view which shows the process of cutting the two glass substrates 41 and 42 which completed the bonding by this bonding method, and forming the injection port 49. As shown in FIG. 8, the thermosetting resin 43 has a closed curve shape on the bonding surface of one glass substrate 41 of the pair of glass substrates 41, 42 and has a convex portion 40 for forming a liquid crystal injection port. On the other substrate 4
Plastic beads 44, which serve as a space holding member, are sprayed on the entire bonding surface of No. 2 and are held by a pair of upper and lower holding members in the same manner as in the present embodiment. The substrates 41 and 42 are aligned. Next, the two glass substrates 41 and 42 are brought close to each other so that the thermosetting resin 43 comes into contact with the entire surface to form a closed space. After that, the surroundings of the glass substrates 41 and 42 are returned to atmospheric pressure, and the glass substrates 41 and 42 are pressed by the difference between the atmospheric pressure and the atmospheric pressure in the closed space to complete the temporary bonding. Further, the temporarily adhered glass substrates 41, 42 are heated to cure the thermosetting resin 43 and to bond them. FIG. 9 shows that the pasting is completed in this way.
The glass substrates 41 and 42 in the state as shown in (1) are cut along the cutting plane line 45 shown in FIG. As shown in 3), a liquid crystal injection port 49 is formed.

The above-mentioned bonding method can also solve the problems that have occurred in the prior art. However, in this method, the projection 40 must be cut to form the injection port 49. A fairly advanced cutting technique is required to prevent defects. Further, since it is impossible to make the inlet shape so complicated, the degree of freedom in designing the closed curve may be lost.

Therefore, the laminating method according to the embodiment of the present invention solves the problems of the prior art and is simpler than the above-mentioned method of forming the injection port 49 by cutting.

[0027]

As described above, according to the present invention, the sticking is performed by using the pressure difference between the closed space in a complete vacuum state surrounded by the two flat plates and the adhesive applied in the closed curve shape and the outside. Since the bonding is performed, it is possible to apply a uniform pressure without being affected by the parallelism of the flat plates to be bonded and without generating a reaction force. Also, the time required for bonding is short.

Therefore, it is possible to improve the reliability and quality of the product and increase the manufacturing efficiency.

[Brief description of drawings]

FIG. 1 is a perspective view of both glass substrates 11 and 12 before laminating in one embodiment of the present invention.

FIG. 2 is a cross-sectional view of both glass substrates 11 and 12 at the start of bonding in one embodiment of the present invention.

FIG. 3 is a cross-sectional view of both glass substrates 11 and 12 at the time of contact with an adhesive in one embodiment of the present invention.

FIG. 4 is a cross-sectional view of both glass substrates 11 and 12 at the time of temporary bonding and completion of bonding in one embodiment of the present invention.

FIG. 5 is a perspective view at the time of completion of bonding in one embodiment of the present invention.

FIG. 6 is a perspective view after the thermosetting resin 18 having a closed curve shape in the embodiment of the present invention is cut and removed.

FIG. 7 is a perspective view showing an application shape example of adhesives 33 and 38 on a glass substrate 31 in another embodiment of the present invention.

FIG. 8 is a perspective view of both glass substrates 41 and 42 before being bonded by another bonding method.

FIG. 9: Both glass substrates 41, 42 by another bonding method
It is a flowchart showing a process of laminating.

FIG. 10: Both glass substrates before bonding 1 according to the prior art
It is a perspective view of FIG.

FIG. 11 is a perspective view of both glass substrates 1 and 2 when the bonding is completed according to the prior art.

FIG. 12 is a cross-sectional view for explaining a pressed state of a conventional pressing method.

FIG. 13 is a cross-sectional view for explaining a conventional vacuum pressing method.

[Explanation of symbols]

 11, 12 Glass substrate 13, 18 Thermosetting resin 14 Plastic beads 15 Glass fiber 20 Closed space

Claims (1)

[Claims] 1. A method of laminating a pair of flat plates facing each other while keeping a constant interval, wherein an adhesive is applied in an open curve shape on the laminating surface of one of the pair of flat plates, and further on the outside thereof. Apply the adhesive in a closed curve, spread a large number of spacing members on the bonding surface of one of the one flat plate and the other flat plate over the entire surface, then overlay both flat plates under reduced pressure, and then at atmospheric pressure outside. A method for laminating flat plates, which is characterized by returning to the lower side and laminating by using the pressure difference between the inside of a closed space surrounded by both flat plates and an adhesive and the outside.