JPS5890617A - Manufacture of liquid-crystal display device - Google Patents

Abstract

PURPOSE:To facilitate assembling operation and to seal an injection hole securely by providing a sealing layer, liquid-crystal injection hole and gate on one transparent substrate in such a way that the gate is in front of the injection hole, and equalizing the height of the barrier to the gap between substrates. CONSTITUTION:On one transparent substrate 1 having electrodes oriented by rubbing, etc., an ultraviolet-ray setting type adhesive (UV adhesive) is printed through a screen to form a gate 8 of the UV adhesive. At this time, the height of the gate 8 is adjusted to the thickness of the gap formed when said substrate is superposed on the other substrate 2 to obtain a liquid-crystal cell. When the gate 8 is formed on a large substrate 1, it serves as a spacer. Then, a sealing layer 3 is printed with an epoxy adhesive, etc., an injection hole 4 for liquid crystal is provided in front of the gate, and the substrate 2 is stuck. After liquid crystal is injected through the injection hole 4, when the hole is sealed with an organic sealing agent 5, a panel cover 7 for display is not stained by the gate 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a liquid crystal display device,
More specifically, the present invention relates to a method of manufacturing a liquid crystal display device having a weir in an injection hole.

In the past, they were generally called organic cells (those in which the alignment process was done by organic rubbing, those in which an organic adhesive was used for the sealing layer between the substrates, or those in which the above two were performed). The liquid crystal display device currently available is as shown in FIG. Not only is the sealing layer 6 made of an organic adhesive, but also the sealant 5 for the injection hole 4 is usually made of an organic adhesive such as Epoquin. A major drawback of this organic sealing agent (sealing agent using an organic adhesive) 5 is that the viscosity is not constant. In other words, since Evoquin-based two-component adhesive is generally used as the organic sealant 5, curing progresses over time and the viscosity changes accordingly. It is.

When the viscosity of the organic sealant 5 is appropriate, as shown in FIG. The injection hole 4 formed by the cutout is inserted into the injection hole 4, but in reality it is quite difficult to control this state, and rather the state shown in Figs. 2 and 3 is likely to occur. There are many. FIG. 2 shows a case where the viscosity of the organic sealant 5 is too low. Since a considerable amount of the tip 5b of the sealant 5 has entered the interior of the organic cell, the alignment state around it changes, resulting in poor alignment, as well as liquid crystal This means that the display device is also a defective product that has lost its aesthetic appearance.

On the other hand, if the viscosity of the organic sealant 5 is too high as shown in FIG. Otherwise, it stops at a position that cannot be reached, and the injection hole 4 is not completely sealed, resulting in a sealing failure that completely lacks the reliability required for a liquid crystal display device. turn into.

(In order to eliminate troubles caused by such organic sealants,
A liquid crystal cell in which a weir 6 is provided near the injection hole as shown in FIG. 4 has also been proposed.

By doing so, the organic sealing agent does not penetrate into the organic cell even if it has a low viscosity, so the sealing work becomes clearly easier. However, as is clear from FIG. 4, the same adhesive is used for the sealing layer 6 and the weir 6, and they are printed at the same time, and then the two substrates are overlaid.
The width of both the sealing 1-6 and the weir 6 expands, and a joint 6a is created between the sealing layer 6 and the weir 6 (only one side is shown in the figure, but in reality both sides are joined, and the injection hole is blocked 75).
I often end up with ζ. ), it may become impossible to inject liquid crystal.

Conversely, if the weir 6 is provided apart from the sealing layer 6, an inward protrusion 6b of the parting line 7 indicating the display portion of the liquid crystal display device will occur in the expansion of the weir 6. ,
This results in poor visual appearance, that is, poor appearance. For this reason, there has been a desire for a method of manufacturing a liquid crystal display device that can form the weir 6 neatly and that does not require trouble in controlling the viscosity of the seal 41 even when sealing the hole after injection. The present invention provides a method for manufacturing a liquid crystal display device that solves these conventional problems.

Hereinafter, the present invention will be explained in detail with reference to the drawings. Figure 6 shows
1 is a process diagram of an embodiment of a method for manufacturing a liquid crystal display device of the present invention. First, as shown in FIG. 6(A), UV curable adhesive 1 (hereinafter referred to as LJV adhesive) is applied to one transparent substrate 1 having electrodes that have been oriented by rubbing or the like with a screen mark 111L and UV adhesive. A weir 8 according to 1 is provided. At this time, the height or thickness of the weir 8 of the UV adhesive is controlled to be equal to the gap between the two substrates when forming a liquid crystal cell (generally 7 to 15 μm).

This method of control is performed by selecting the mettsu of Suf 1 Noon; the height of the printed weir 8 and the Metsu/yu of Suf 1 Noon have a relationship as shown in Figure 7. , is not affected by the viscosity of the UV adhesive.

The UV adhesive weir 8 thus formed on one substrate 1 is irradiated with ultraviolet light (hereinafter referred to as FUV irradiation) in this state to harden it.

UV irradiation time is generally about 15 seconds to 5 minutes,
Although it differs depending on the type of V-adhesive and the printing thickness, in the examples of the present invention, it took 30 to 60 seconds. After this, the 6th
As shown in Figure (B), a ring layer 6 made of organic adhesive is formed on one substrate 1 (or the other substrate 2) by screen printing.
printed on.

The organic adhesive used for this sealing layer B is an epoxy two-component adhesive.

FIG. 6(C) shows a state in which one substrate 1 and the other substrate 2 are superimposed. In this case, UV
While the height of the adhesive weir 8 is equal to the gap of the liquid crystal cell, the height of the ring no. 6 is printed higher than that.

In the state shown in FIG. 6(D), the two substrates 1.2 are overlapped and pressed. At this time, since the UV adhesive weir 8 has already been cured, the two substrates 1.2 will be overlaid with the gap equal to the height K of the UV adhesive weir 8. , since the thickness of the weir 8 is constructed to be equal to the gap of the liquid crystal cell, the layer 8 serves as a spacer for adjusting the thickness am of the gate. When heated and fired in this state, it becomes an organic cell. FIG. 6(E) is a plan view of the organic cell, and FIG. 5 is a plan view of the liquid crystal display device formed by injecting a liquid crystal material and sealing the pores.

The fired sealing layer 6 shown in FIGS. 5 and 6(g) is similar to the sealing layer 6 shown in FIG. 4 in the conventional example, and is not a linear sealing layer. However, unlike the conventional case, the weir 8 made of UV adhesive is linear and does not increase in width, so it does not bond with the sealing layer 6 and an appropriate gap 9 can be created. Furthermore, there is no intrusion due to the expansion of the weir 8 inside the parting line 7 of the liquid crystal display device. Furthermore, when the liquid crystal material is injected and sealed, the organic sealant 5 enters the organic cell through the injection hole 4, hits the UV adhesive weir 8, and passes through the gap 9 along the weir 8. flows. However, since the length of the weir 8 is more than ten times the width of the injection hole 4, the gap 9
f: There is no possibility that it will pass through and reach the inside of the organic cell.

Therefore, even if the organic sealant 5 is made of a two-component mixed type epoxy/based adhesive and its viscosity changes over time, by always using the viscosity at a low level, sealing defects (organic This prevents the organic sealant from entering the cell or preventing the organic sealant from reaching the injection hole. This method of providing the weir 8 is particularly effective when using a UV adhesive with a low viscosity as the organic sealant. The weir 8 up to Ar is formed using a UV adhesive, and the sealing layer 6 is formed using an organic adhesive such as an epoxy adhesive. It may also be attached with an adhesive.

That is, the adhesive forming the weir 8 and the sealing layer 6 is U.
Combinations such as V-epoxy, UV-UV, epoxy-UV, and epoxy-epoxy may be used. However, the forming method, that is, the manufacturing method, is such that the weir 8, which is a feature of the present invention, is first formed to have a thickness equal to the liquid crystal cell gap,
It is necessary to undergo a method of curing in that state, then forming a sealing layer 6, overlapping, pressing, and firing.

Another embodiment of the present invention is one in which a plurality of liquid crystal cells are formed simultaneously as shown in FIG. Similar to the manufacturing method described above, a plurality of weirs 8 of UV adhesive are screen printed on one substrate 1 as shown in FIG. The thickness of the weir 8 is the same as the gap of the liquid crystal cell, and in this state, UV irradiation is applied to the weir 8.
harden.

Thereafter, the other substrate 2 on which the sealing J-6 is formed is superimposed, and at this time, the weir 8 serves as a spacer to keep the gap between the liquid crystal cells constant.

In the explanation of FIG. 6, the weir 8 was only on one side, so it was not perfect as a spacer, but in the method of simultaneous formation of multiple pieces, which is a common method for manufacturing liquid crystal cells, as shown in FIG. Since the weirs 8 are almost evenly distributed on one substrate 1, they completely serve as spacers when stacked on the other substrate 2. Therefore, unlike the conventional method in which a spacer material is mixed into the sealing layer 6 to regulate the gap of the liquid crystal cell, there is no need to mix a special spacer material into the sealing layer B, making the work easier. It also contributes to simplification and material savings.

Of course, the effect of not bonding the weir 8 and the sealing layer 6 is as explained above.

As described above, according to the method for manufacturing a liquid crystal display device of the present invention,
First, the weir 8 near the injection hole 4 is printed and cured, so the weir 8 is linear and does not expand.After this, the sealing layer 6 of the organic cell is formed and the two substrates are stacked. Since the bonding is performed, even if the sealing layer 6 expands a little, it will not be joined to the weir 8, and an appropriate gap 9 will be maintained between them to complete the organic cell. In other words, the greatest advantage is that it can eliminate the drawback of the conventional example that the injection hole 4 is blocked. Furthermore, when injecting a liquid crystal substance and sealing the hole, even if a relatively low viscosity adhesive such as UV adhesive or epoxy adhesive is used as the organic sealant 5, it will remain in a low viscosity state where hardening does not proceed. It also has the advantage that it can be used without causing sealing defects. Furthermore, whereas conventionally a spacer material was mixed into the sealing layer 6 to regulate the gap, in the present invention, the weir 8 is printed in advance to a thickness equal to the gap and hardened.
Even without mixing spacer material into the sealing layer 6,
It also has the advantage of being able to control the gap between organic cells. Regarding this gap regulation, as shown in Figs. 8 and 9, the effect is most remarkable when the so-called multiple simultaneous formation method is adopted, but even in the case shown in Fig. 6, the weir 8 At the same time as the layer 8 is formed, a part of the auxiliary spacer is formed of the same material as the weir 8 on the opposite side of the layer 8, and if it is cured at the same time as the weir 8 is cured, the gap regulation can be made more complete. Become.

[Brief explanation of drawings]

Figures 1 to 4 are diagrams showing a conventional liquid crystal display device, Figures 1 to 3 are plan views showing the state of sealing with an organic sealant, and Figure 4 is a weir and a sealing J. The plan views shown in FIGS. 5 to 9, which show the relationship between - and FIGS. Fig. 5 is a plan view showing the relationship between the weir, sealing layer, and sealing hole, Fig. 6 (A) to (E) is a process diagram showing the manufacturing method, and Fig. 7 is a plan view showing the relationship between the weir, the sealing layer, and the sealing hole. A graph showing the relationship with screen methodology, Fig. 8 is a plan view showing the case where a plurality of organic cells are formed at the same time, and Fig. 9 is a plan view showing the state in which a weir is printed on one substrate.1 ...One substrate 2...Other substrate 6...Sealing layer 4...Injection hole 5.
...Organic sealant 6.8...Weir Figure 1 - Figure 2 b Figure 3 Figure 4 Figure 6 (A) (B) δ (C) Figure 7

Claims (2)

[Claims] (1) In a liquid crystal display device in which a liquid crystal substance is injected through an injection hole formed by cutting out a part of a sealing layer between two substrates having electrodes, an organic adhesive is attached near the injection hole of one substrate. A weir made of an organic adhesive is formed by screen printing, the organic adhesive is cured in that state, and then a sealing layer made of an organic adhesive is formed on one of the substrates or the other substrate by a screen printing method, and the organic adhesive is cured in that state. After overlapping two substrates and pressurizing them to maintain a predetermined distance,
A method for manufacturing a liquid crystal display device, comprising curing a sealing layer. (2) The method for manufacturing a liquid crystal display device according to claim 1, wherein the weir is made of an ultraviolet curable organic adhesive.