JPH04371926A - Production of liquid crystal display device - Google Patents

Abstract

PURPOSE:To prevent the generation of the unequal spacing between substrates and to improve a display grade by forming sealing materials having discharge ports on the respective sides of the substrates. CONSTITUTION:The sealing materials 16 having the discharge ports 31 are formed on the respective sides of the substrates 10 and thereafter, two sheets of the substrates 10 are combined in the production of the liquid crystal display device constituted by combining two sheets of the substrates 10 formed with transparent electrodes and oriented films by the sealing materials 16 in such a manner that the substrates face each other via spacers and clamping a liquid crystal in the spacing therebetween. After the parts exclusive of the part to constitute the injection port of the liquid crystal among the discharge ports 31 are sealed, the liquid crystal is injected from the injection port. Namely, the air between the substrates 10 can be sufficiently discharged from the discharge ports 31 provided on the respective sides and, therefore, the nonuniformity of the spacing between the substrates occurring in the expansion of the internal air or unequal discharge in a heating stage is prevented.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal display.

0002

2. Description of the Related Art A liquid crystal display is constructed, for example, as shown below. That is, a transparent electrode and an alignment film are formed on one main surface of two substrates, the two substrates are assembled using a sealing material so that one main surface side faces each other, and a liquid crystal is placed in this gap. inject. On the other hand, a polarizing plate and a retardation plate are attached to the other main surface of one of the two substrates, and a polarizing plate is attached to the other main surface of the other two substrates. FIG. 3 is a plan view showing the shape of a sealant on a substrate in a conventional liquid crystal display. As shown in Fig. 3, sealing material 1
is printed on the substrate 2 by a printing process such as screen printing around the area where the liquid crystal is to be sealed. At this time, an injection port 3 is usually provided in a part of the sealing material 1, and after the upper and lower substrates are sealed, liquid crystal is injected from this part.

0003

[Problems to be Solved by the Invention] Normally, when sealing upper and lower substrates, the sealing material is cured while being heated after bonding in order to promote the effectiveness of the adhesive. At this time, the important point is that no excess air remains between the substrates where the liquid crystal is injected. However, in the past, there was only one inlet.
Since there were only one or two, air could not be efficiently evacuated during sealing, and excess air remained between the substrates. If the sealing material is cured while being heated in this state, the remaining air will expand during the curing process, and as a result, the gap between the substrates will widen. Normally, when comparing the periphery and the center, the distance between the substrates is wider in the center.

Furthermore, if the exhaust is not efficiently emitted during sealing, unevenness will occur in the evacuation, and if the sealing material is allowed to harden as it is, this will lead to unevenness in the spacing between the substrates, resulting in uneven display. The uniformity of the gap varies depending on the display mode of the liquid crystal used, but the uniformity of the gap varies depending on the display mode of the liquid crystal used.
Nematic) type, 0.5 μm, STN (Super
r Twisted Nematic) type with 0.05μ
m, and very high precision is required. Therefore, the above-mentioned unevenness in the spacing between the substrates causes fatal display defects.

[0005] As described above, in the conventional method for manufacturing a liquid crystal display, when the upper and lower substrates are sealed together, the air is not efficiently evacuated, and excess air remains between the substrates. Since the substrates are heated in this state, the remaining air expands and the distance between the substrates increases. Furthermore, if the exhaust is not efficiently emitted during sealing, unevenness in evacuation occurs, which results in unevenness in the spacing between the substrates, resulting in uneven display. This invention was made in view of such conventional circumstances.

[0006]

[Means for Solving the Problems] The present invention provides space between two substrates on which transparent electrodes and alignment films are formed using a sealing material.
The present invention relates to a method for manufacturing a liquid crystal display device, in which the liquid crystal display devices are assembled so as to face each other with a gap between them, and a liquid crystal is sandwiched between the two. After forming a sealant having an outlet on each side on at least one of the two substrates, the process of assembling the two substrates and sealing the outlet except for the part that will become the liquid crystal injection port is performed. After stopping, the liquid crystal is injected from the injection port.

[0007]

[Function] In this invention, when two substrates are sealed together, the air between the substrates can be sufficiently exhausted from the plurality of exhaust ports provided on each side of the sealing material. This makes it possible to prevent uneven substrate spacing caused by uneven expansion or exhaust of internal air.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be explained below with reference to the drawings.

FIG. 1 is a sectional view showing a liquid crystal display obtained according to an embodiment of the present invention. In FIG. 1, an explanation will be given according to the manufacturing process. First, for example, an I
Transparent electrodes 12 and 13 made of TO and alignment films 14 and 15 made of polyimide, for example, are sequentially formed. Then, the two substrates 10 and 11 are placed so that one main surface side faces each other.
For example, the seal material 16 made of epoxy resin can be used to seal the space.
They are assembled together via a sensor 17, and a liquid crystal 18 is held in this gap. Further, a polarizing plate 19 is sequentially attached on the other main surface of the substrate 10, and a retardation plate 20 and a polarizing plate 21 are attached on the other main surface of the substrate 11.

FIG. 2 is a plan view showing the shape of the sealing material 16 on the substrate 10 before the substrates 10 and 11 are combined. In FIG. 2, the sealing material 16 is applied to at least one of the two substrates 10 and 11, for example, on the substrate 10, by a printing process such as a screen printing process, around the area where the liquid crystal 18 is sealed. A plurality of discharge ports 30 and 31 are provided on each side of the seal portion. And the substrate 10,1
1, and after curing the sealant 16, the liquid crystal 18
The discharge ports 31 other than the discharge port 30 serving as the injection port are sealed. Furthermore, after reducing the pressure between the substrates 10 and 11 and injecting the liquid crystal 18, the discharge port 30 is finally sealed while pressurizing the excess liquid crystal to the outside.

In this embodiment, when the substrates 10 and 11 are sealed, excess air between the substrates 10 and 11 is efficiently exhausted through the exhaust ports 30 and 31 provided on each side of the sealing material 16. Therefore, the gap between the substrates 10 and 11 increases in the center,
There is no longer any unevenness in the spacing depending on the location, and display unevenness has been reduced.

0012

According to the present invention, by forming a sealing material having an outlet on each side on at least one of two substrates, unevenness in the spacing between the substrates can be prevented during sealing.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a liquid crystal display obtained according to an embodiment of the present invention.

FIG. 2 is a plan view showing the shape of a sealing material in an embodiment of the present invention.

FIG. 3 is a plan view showing the shape of a sealing material in a conventional liquid crystal display.

[Explanation of symbols]

10, 11...Substrate 12, 13...Transparent electrode 14, 15...Alignment film 16...Sealing material 17...Spacer 18...LCD 30, 31...Exhaust port

Claims (1)

[Claims] 1. Manufacture of a liquid crystal display in which two substrates on which transparent electrodes and alignment films are formed are combined with a sealant so as to face each other with a spacer interposed therebetween, and a liquid crystal is sandwiched between the two substrates. In the method, after forming a sealing material having an outlet on each side on at least one of the two substrates, combining the two substrates; A method for manufacturing a liquid crystal display device, comprising the step of injecting the liquid crystal from the injection port after sealing other than the portion where the liquid crystal is formed.