JP2588218B2 - Liquid crystal display manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a method for manufacturing a liquid crystal display device in which a sealing material is pressed.

(Prior Art) In general, a liquid crystal display applies a sealing material to one of a pair of transparent substrates on which a transparent electrode is formed by printing or the like, overlaps the pair of transparent substrates with a spacer interposed therebetween, and interposes the spacer. After the transparent substrate thus formed is pressure-sealed and a liquid crystal material is injected between the pair of transparent substrates, a polarizing plate is arranged outside the transparent substrate.

In addition, an epoxy resin-based thermosetting type is generally used for the sealing material. Generally, in order to maintain a uniform gap between a pair of transparent substrates, the size of the liquid crystal display is adjusted according to the size of the liquid crystal display. A method of heating and curing the sealing material while applying pressure with a pressing force is employed. Furthermore, the time required for curing the sealing material is within one hour. However, since the productivity is poor with pressure bonding by one piece, a plurality of pieces are stacked together and sandwiched with a platen having an appropriate weight. And pressurize.

However, in such a method, it takes time for the temperature required for curing to be transmitted to all of the stacked liquid crystal displays,
The seal crimping time can be several hours. In addition, with such a stacking method, it is difficult to apply a uniform desired pressing force to each liquid crystal display, and a uniform gap does not appear or the seal shape is distorted depending on the stacking position of the liquid crystal displays. Often. In recent years, not only glass but also a plastic film has been used as the transparent substrate. In such a case, when the seal pressure bonding is performed by the method described above, the transparent substrate itself using the film becomes Since it is not as flat as glass and has flexibility, a uniform pressing force is not applied to the entire transparent substrate. Furthermore, when a thermosetting sealing material is used, dimensional changes such as shrinkage occur during the pressing, and it is difficult to apply an even more uniform pressing force.

From the above, conventionally, for example, JP-A-61-14
The method described in Japanese Patent No. 5586 is known. This JP
According to the method described in JP-A-145586, a combination of a pair of transparent substrates is inserted into a bag of a plastic sheet material, and the bag is pressure-sealed by reducing the pressure inside the bag.

However, a semi-finished product obtained by combining a pair of glass substrates via a sealing material is in an extremely susceptible state because the sealing material is still uncured unless the stationary state is maintained, and in a method such as packing in a simple bag, Even if a pair of transparent substrates are combined with high precision, there is a very high possibility that they will be misaligned. In this case, a means of temporary fixing is also conceivable, but the number of steps is increased and the production efficiency is not good. Furthermore, it is necessary to devise a device so that it does not move after being put in the bag, but it is difficult to fix the bag because it is a plastic film.

As a method of pressure sealing using such a transparent substrate as a plastic film having the same plasticity as that of a bag instead of a material such as glass, for example, Japanese Patent Application Laid-Open No.
The method described in 8018 is known. This Japanese Patent Laid-Open No. 57
In Japanese Patent Application Publication No. 188018, a transparent substrate is sealed in a container made of silicon rubber and a stainless steel plate while being sucked, and sealed by applying pressure.

(Problems to be Solved by the Invention) However, in the method described in JP-A-57-188018, since a thermosetting sealing material is used, dimensional changes such as shrinkage occur during press-fitting, and uniformity occurs. There is a problem that it is difficult to apply an appropriate crimping force and the gap may not be maintained uniformly.

The present invention has been made in view of the above problems, and it is possible to always apply a uniform pressing force to a liquid crystal display at the time of seal pressing, and to obtain a liquid crystal display that maintains an extremely uniform gap, and It is another object of the present invention to provide a method of manufacturing a liquid crystal display device that enables sealing and pressure bonding in a short time.

[Configuration of the invention]

(Means for Solving the Problems) In the method for manufacturing a liquid crystal display of the present invention, an ultraviolet-curable sealing material is attached to at least one of a pair of transparent substrates on which a desired transparent electrode is formed, and the pair of transparent substrates is formed. In a state where the transparent substrates are combined via a spacer, the suction port is placed on a glass plate that transmits ultraviolet light provided on the opposite side, and the pressure-bonding film is covered on the plate, The pair of transparent substrates are pressure-sealed by sucking the pressure-bonding film while irradiating ultraviolet rays from the surface plate side to cure the sealing material.

(Function) The present invention provides a pressure-bonding film that is obtained by attaching an ultraviolet-curable sealing material to at least one of a pair of transparent substrates and combining them via a spacer, and then arranging them on a glass plate having translucency. , And the film is sucked by suction holes provided at opposite edges of the platen to apply a uniform pressing force to the assembled product.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a liquid crystal display 1. In manufacturing the liquid crystal display 1, a pair of transparent substrates 2,
Transparent electrodes 4 and 5 having a desired pattern are formed on the inner surface of 3, and alignment films 6 and 7 such as polyimide resin are applied. Then, a seal material 8 of an ultraviolet-curable adhesive such as an acrylic or epoxy is applied to the inner surface of the edge of at least one of the transparent substrates 2 by screen printing or the like.
The spacer 9 is arranged on the other transparent substrate 3. And
The pair of transparent substrates 2 and 3 are overlapped via the spacer 9.

The semi-finished product 1a thus obtained is set in the crimping device 11 shown in FIG. In the crimping device 11, a surface plate 13 is disposed above a machine frame 12, and the surface plate 13 is formed of a material that sufficiently transmits ultraviolet rays, for example, glass. An internal precision of about 50 to 100 μm is sufficient.
In addition, at least two or more suction ports 14 connected to a vacuum suction device are provided at the front end of the surface plate 13,
A positioning piece 15 is provided on the upper surface.

Further, a plastic crimping film 16 is wound in a roll shape at the front of the machine frame 12, and a locking member 17 is provided at a rear portion of the machine frame 12. A light source 18 such as a high-pressure mercury lamp is provided in a lower portion of the machine frame 12, and a cover 19 is provided on the upper portion of the machine frame 12 so as to be freely opened and closed. And, as the pressure-bonding film 16, it is preferable that the film is thinner than the thicker one.
A suitable material is a plastic film such as polyethylene terephthalate, polyethersulfone, or Teflon film.

Then, the semi-finished product 1a is arranged on the surface plate 13, and the front end is abutted against the positioning piece 15 to be positioned and installed. Then, the crimping film 16 wound forward is pulled out to the front, and as shown in FIG. 3, almost the entire surface of the platen 13 is covered, and the leading end of the crimping film 16 is locked to the machine frame 12. It is held by the tool 17.

Then, a suction port provided along the front edge of the surface plate 13
When vacuum suction is applied from 14, the pressure-bonding film 16 is brought into close contact with the semi-finished product 1a by the negative pressure due to the suction as shown in FIG. With this,
The semi-finished product 1a is irradiated with ultraviolet rays by the light source 18 to cure the sealing material 8.

Then, liquid crystal is sealed between the pair of transparent substrates 2 and 3 to complete the liquid crystal display 1.

Further, as for the degree of negative pressure due to suction, since the pressure force varies depending on the size of the liquid crystal display 1, the degree of vacuum may be selected according to this.

According to the experiment, if the suction port 14 is provided along one side of the take-up side of the pressure-bonding film 16 on the surface plate 13, it is sufficient to perform uniform pressure bonding, but by providing the suction port 14 also on the opposite side. Adhesion can be made more reliably.

In the liquid crystal display manufactured in this manner, a variation between rods is extremely small, and a liquid crystal display having a uniform gap between the pair of transparent substrates 2 and 3 can be obtained.

Next, FIG. 5 shows a case where a plastic film is used as a pair of transparent substrates of a liquid crystal display.

In addition, as a pair of transparent plastic films 2a and 3a to be a pair of transparent substrates 2 and 3, an organic film such as polyethersulfone or polyethylene terephthalate is used, and the pair of films 2a and 3a have opposite surfaces. The transparent electrodes 4 and 5 and the alignment films 6 and 7 having a desired pattern are formed, and the pair of films 2a and 3a are pulled out from the roll body and sent through the guide rollers 21 and 22 of the transfer device. Then, an ultraviolet-curable sealing material 8 is applied to one film 2a by a screen printing machine 23, and spacers 9 are sprayed on the other film 3a by a spray device 24. Subsequently, the pair of films 2a and 3a are assembled with high accuracy by a lead hole or the like by the assembling device 25 and guided to the crimping device 11.

The crimping device 11 has slit-shaped suction ports 14 formed along both sides of a surface plate 13. Both sides of a film 16 for crimping are inserted into the suction ports 14 on both sides of the platen 13. Above the film 16, a support 26 such as vacuum tweezers is arranged.

Then, when the pair of films 2a and 3a combined above is positioned on the surface plate 13, the crimping film 16 held by the support 26 separates and is pulled downward by suction from the suction port 14, so that the crimping is performed. Film 16 is film 2a, 3a
The sealing material is hardened by ultraviolet light by turning on the light source 18 at the stage where the pressure is applied until a sufficient gap comes out, and the sealing material is hardened, and the sealing is completed.

By performing the sealing process in this manner, the sealing is completed in a short time, without impeding the index as a continuous processing step, and by applying a uniform pressure,
A liquid crystal display having a highly accurate gap can be obtained.

Then, after the completion of the pressure bonding, the support 26 descends on the pressure-bonding film 16 brought into close contact with the films 2a and 3a, and pulls the pressure-bonding film 16 upward.

Transparent substrates 2 and 3 are plastic film 2
a, 3a, it is difficult to apply a uniform force to the entire surface with a sled of glass or the like, even if the film is sandwiched between rigid bodies such as glass, for example, and the film 2a, 3
Since a itself is also plastic, the properties of the rigid body to be clamped are particularly easy to appear, the distribution of the applied force is also poor, and it is extremely difficult to apply a uniform pressing force. Pressurization is easily performed, and therefore, it is particularly effective when the films 2a and 3a are used for the transparent substrates 2 and 3.

In each of the above embodiments, the case of irradiating ultraviolet rays from below was shown.However, ultraviolet rays may be irradiated from above. In this case, it is preferable to use a Teflon film or the like having good ultraviolet transmittance as the pressure-bonding film 16. desirable.

It is very effective to use a UV-curable sealing material and an organic film such as polyethersulfone (PES) or polyethylene terephthalate (PET) as a transparent substrate. Even when a transparent substrate is used and a transparent substrate such as glass is used, uniform pressing force and uniform heating are possible, and similar effects can be expected.

〔The invention's effect〕

According to the present invention, an ultraviolet-curable sealing material is attached to at least one of a pair of transparent substrates and combined via a spacer, and then placed on a glass platen to cover a pressure-bonding film. Is suctioned by suction ports provided on the opposite edges of the platen and pressure-sealed, so that a uniform pressing force can be applied to the whole and the sealing process can be performed in a short time. Therefore, it is possible to easily obtain a liquid crystal display having a high-precision and uniform gap. Particularly, in a case where a transparent substrate such as a plastic film is used, the compression force is reduced due to a dimensional change such as shrinkage during heat compression. Variation can be suppressed.

[Brief description of the drawings]

1 is a sectional view of a liquid crystal display, FIGS. 2 to 4 are process diagrams showing one embodiment of the method of the present invention, and FIG. 5 is a perspective view showing another embodiment of the method of the present invention. is there. 1 ... Liquid crystal display, 2,3 ... Transparent substrate, 4,5 ... Transparent electrode, 8 ... Seal material, 9 ... Spacer, 13 ... Stable plate, 14
…… Suction port, 16 …… Crimping film.

Claims (2)

(57) [Claims] An ultraviolet-curable sealing material is attached to at least one of a pair of transparent substrates on which a desired transparent electrode is formed, and the pair of transparent substrates are combined via a spacer, and the suction ports are opposed to each other. It is installed on a glass surface plate that transmits ultraviolet light provided on the edge portion to be covered, a film for pressure bonding is covered on this surface plate, and the ultraviolet light is irradiated from the surface plate side to cure the sealing material. A method for manufacturing a liquid crystal display, wherein a pair of transparent substrates are pressure-sealed by sucking a film for pressure bonding. 2. The method according to claim 1, wherein the pair of transparent substrates is an organic film.