JPH0196624A - Liquid crystal display panel and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain display of high quality having no defect in orientation and long-period high reliability by arranging a spacer in a groove part provided on a part of a liquid crystal injection opening and sealing its outer periphery with an adhesive. CONSTITUTION:Substrates 11 and 12 have their outer peripheral parts stuck together with a sealing material 13 to form a gap, into which liquid crystal 14 is injected from the liquid crystal injection opening 15. Then the injection of the liquid crystal is completed, the spacer 17 is engaged with the grove parts 16 of the liquid crystal injection opening 15 and inserted, and the peripheral part 17 is sealed with the adhesive 18. Therefore, the injected liquid crystal 14 and the adhesive 18 sealing the liquid crystal injection opening 15 are hardly brought into contact with each other to eliminate the fusion of the adhesive 18 into the liquid crystal 14 at the time of the sealing, the chemical reaction on the liquid crystal 14 at the time of adhesive setting, or the chemical reaction between the adhesive 18 and liquid crystal 14 and the elution of adhesive components into the liquid crystal 14 after the sealing. Consequently, the high quality and reliability are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Fields] The present invention has a sandwich structure in which a liquid crystal is sealed in the gap between two substrates, and a liquid crystal is sealed between electrodes provided on the inner surface of the substrates for image formation. This article describes liquid crystal display panels that perform various displays by applying voltage and controlling the amount of light transmitted through internal liquid crystals, and their manufacturing and methods.

[Prior Art] Liquid crystal display panels have been put to practical use in the displays of wristwatches, calculators, etc., but liquid crystals generally react with oxygen and moisture and tend to deteriorate, so liquid crystals are vacuum-injected into liquid crystal display panels. , Sugadori completely hermetically seals the container after injection.

In addition, in recent years, liquid crystal display panels have become higher in density, faster, and larger in area, and have also been put to practical use in liquid crystal televisions, liquid crystal shutters, etc.

3rd v! I is a diagram showing a conventional liquid crystal display panel, (A)
is a plan view, and (b) is a cross-sectional view taken along line FF' in figure (a). Reference numeral 112 designates transparent substrates, such as glass substrates, and by bonding their outer peripheries together with a sealing material 3 such as epoxy resin while facing each other, a liquid crystal enclosure space is formed. Next, this panel is placed in a vacuum chamber, the liquid crystal enclosure space is evacuated, and the injection port 5 is sealed with adhesive lO while the liquid crystal 4 is sucked through the injection port 5. Thereafter, a polarizing plate and a reflecting plate are stacked on the back side of the panel, and a polarizing plate is stacked on the front side, thereby completing a liquid crystal display panel. Note that a pattern of transparent electrodes 6.7 is formed in advance on the inner surface of the substrate 1.2, and a molecular alignment film 8.9 is applied from above the transparent electrodes 6.7.
is formed.

A method for inhaling the liquid crystal from the injection port 5 is to immerse the injection port 5 of the panel from which the liquid crystal enclosed space has been evacuated into a tank containing the liquid crystal, and to draw the liquid crystal into the liquid crystal enclosed space under negative pressure. There are methods such as dropping the liquid crystal into the injection port 5 of the panel where the liquid crystal enclosed space is evacuated and inhaling it under negative pressure.

[Problems to be Solved by the Invention] However, in such a liquid crystal display panel and its manufacturing method, the adhesive 10 has a structure in which the adhesive 10 is bonded while being in direct contact with the liquid crystal 4. After sealing, chemical changes and deterioration of the liquid crystal in the vicinity of the injection port gradually progress and spread, and display defects such as poor alignment occur, so that reliability is not necessarily excellent. In addition, when applying adhesive to the sealing opening after injecting liquid crystal to seal it, the liquid crystal may be significantly contaminated due to factors such as the adhesive melting into the liquid crystal before curing is completed due to light, heat, etc. However, there were problems such as misalignment occurring over a wide area and spreading over the side surface of the substrate on the side of the injection port, making it difficult to completely seal the injection port and requiring time and effort.

In particular, in liquid crystal display panels using ferroelectric liquid crystal exhibiting a chiral smectic C phase, etc., the viscosity of the ferroelectric liquid crystal is extremely high, so the liquid crystal injection port is widened to make it easier to inject the liquid crystal and shorten the injection time. As a result, the contact area between the adhesive and the liquid crystal becomes significantly larger, and the above-mentioned problems can be overcome in order to achieve high quality and reliability of the liquid crystal display panel, improved manufacturing yield, and inexpensive mass production. This was a major bottleneck.

c. Means for Solving Problems] The liquid crystal display panel of the present invention has a liquid crystal display panel in which a liquid crystal injected from a liquid crystal injection port is interposed between a pair of substrates having electrodes. A groove is provided in the portion, a spacer is provided in the groove, and the outer periphery of the spacer is sealed with an adhesive.

Further, in the method for manufacturing a liquid crystal display panel of the present invention, a sealing material is provided at the periphery between a pair of substrates having electrodes to form a gap, liquid crystal is injected into the gap from a liquid crystal injection port, and then the liquid crystal is injected into the liquid crystal injection port. A spacer is inserted into a groove provided in advance in at least a portion of the spacer, and the outer periphery of the spacer is further sealed with an adhesive.

Hereinafter, some specific examples of the liquid crystal display panel of the present invention and its manufacturing method will be explained with reference to FIGS. 1 and 2.

1rM (a) to (e) are plan views showing some specific examples of the liquid crystal display panel of the present invention, and FIGS. A-A', B-B', c-c', D in I
It is sectional drawing which shows some specific examples along the line -D' and EE'.

In the figure, 11 and 12 are substrates, which are glass plates.

The resin plate may be made of a flexible polymer film such as polyethylene terephthalate film, polybutylene terephthalate film, polyether sulfone film, or polycarbonate film.

The mutually opposing inner surfaces of the substrates 11, 12 are provided with electrodes and alignment films (not shown). This electrode may be entirely transparent or partially transparent, and forms an arbitrary pattern.

These substrates 11 and 12 are bonded together at their outer peripheries with a sealing material 13 such as epoxy resin or acrylic resin to form a gap, and a liquid crystal 14 is injected into the gap by a method such as a vacuum injection method. The liquid crystal is injected through the liquid crystal injection port 15.

Note that in the present invention, the liquid crystal injection port is not limited to the opening of the gap formed by the sealing material 13;
The portion corresponding to the liquid crystal injection route that does not exist in No. 3 and its surrounding area are also shown.

Examples of the liquid crystal 14 include cholesteric liquid crystal, nematic liquid crystal, smectic liquid crystal, mixtures thereof, and those mixed with additives such as dyes.

The liquid crystal injection port 15 is provided with grooves 16 of various shapes as shown in FIG. 2, for example. In this figure, there is a groove 1 on the board.
6 is provided, but a similar groove may be provided at the frontage of the sealing material 13. In addition, the inter-substrate gap in the groove 16 is larger than the inter-substrate gap in the visible display section filled with liquid crystal, and has a structure in which liquid crystal is easily injected, but it is similar to or smaller than the inter-substrate gap in the display section. Furthermore, the shape of the groove portion 16 is not limited to that shown in FIG. 2, as there are various other shapes.

Then, when the liquid crystal injection is completed, the liquid crystal injection port 15
The spacer 17 is inserted by engaging the groove 16 of the spacer 17. The spacer 17 may be made of indium, for example, as long as the portion in contact with the liquid crystal 14 does not have a chemical effect on the liquid crystal 14.
Made of metals such as gold, aluminum, lead, zinc, tin, solder, etc., and inorganic materials such as metal oxides, metal oxides, and metal nitrides, either singly or in various composites or combinations. etc. are used. In addition, synthetic resins such as acrylic resin, silicone resin, acetal resin, and fluororesin, or rubber, etc. may be used alone or in combination with other materials. In particular, fluororesins such as tetrafluoroethylene and chlorotrifluoroethylene are chemically stable and preferred;
If the spacer 7 has plasticity, elasticity, etc., the spacer 17 can be tightly fixed in the groove 16 by press-fitting, so that the liquid crystal sealing property is excellent and the spacer 17 can be maintained stably fixed. For example, thin wires made of relatively soft metals, synthetic resins, rubber, etc. as shown above are thin wires made of polymeric materials with plasticity and elasticity whose surface is coated with metal, or at least the outer periphery is coated with metal. Those coated with the synthetic resin, rubber, etc. mentioned above are preferably used.

Further, the shape of the spacer is not limited to a cylindrical shape or a square prism shape, but various shapes such as an elliptical shape, a polygonal column shape, a rectangular shape, a spherical shape, and a cylindrical shape are used.

In addition, a spacer is created using a shape memory alloy, and after it is inserted into the groove of the liquid crystal injection port, the shape of the spacer is changed by applying a certain temperature change such as heating or cooling, and the spacer is engaged and fixed in the groove. You can also do it.

Furthermore, the periphery of the spacer 17 is sealed with an adhesive 18 in order to reinforce the fixation of the spacer and complete encapsulation of the liquid crystal.

As the adhesive 18, for example, an epoxy-based or silicon-based resin adhesive or a commercially available ultraviolet curable adhesive is used, and the adhesive 18 is used to form the spacer 17, the groove portion 1, the substrate 11,
12. It is preferable to cover the liquid crystal 14 in contact with the sealing material 13 so that it does not leak completely, and then harden it by heating or light irradiation to perform sealing.

A polarizing plate and the like are further attached to the liquid crystal display panel created in this manner.

According to such a liquid crystal display panel and its manufacturing method, there is almost no contact between the injected liquid crystal and the adhesive sealing the liquid crystal injection port, and the adhesive melts into the liquid crystal during sealing. Chemical reactions with the liquid crystal during hardening of the adhesive, chemical reactions between the adhesive and the liquid crystal after sealing, and elution of components in the adhesive into the liquid crystal do not occur.

Further, the spacer can be easily and stably fixed to the liquid crystal injection port, and the liquid crystal injection port can be quickly and reliably closed.

Therefore, it is possible to form a wide liquid crystal injection port, inject liquid crystal in a short time, and then easily perform reliable sealing.

It should be noted that the present invention is not limited to the above specific examples within the scope of the invention.

[Example 1] Transparent electrodes made of ITO (indium tin oxide) were formed on the surfaces of two glass substrates and patterned. Next, an alignment film made of polyimide resin was formed on the transparent electrodes and rubbed. On one of the substrates, use a diamond cutter to cut the 21st! A groove with a depth of about 300 μm is provided as shown in I (a).

These two substrates are placed facing each other with the transparent electrodes on the inside, and a gap agent of alumina powder with a particle size of about 2 μm is interposed and provided on three sides of the periphery of the substrate as shown in Figure 1 (d). They are pasted together using a band-shaped sealing material made of epoxy resin, and then bonded and fixed by heating.

Smectic liquid crystal was injected into the void in the liquid crystal cell thus created using a vacuum injection method. After that, solder processed into a thin line with a diameter of 350 μm is press-fitted into the groove of the liquid crystal injection port to block the outflow of liquid crystal, and the outer periphery is coated with an ultraviolet curing adhesive and irradiated with ultraviolet rays to cure and seal. did.

The liquid crystal display panel created in this way shows uniform and good alignment throughout, with no alignment defects near the liquid crystal injection port.
The work could be carried out easily and with a good yield.

In addition, this liquid crystal display panel was subjected to a high-temperature test at a temperature of 80°C and a high-temperature test at a temperature of 46°C and a relative humidity of 90%, but no alignment failure occurred near the liquid crystal injection port, and no alignment failure occurred in the display area. No defects were observed.

[Effects of the Invention] As explained above, according to the present invention, at least a part of the liquid crystal injection port is provided with a groove, a spacer is installed in the groove, and the outer periphery of the spacer is sealed with an adhesive. Since there is almost no contact between the liquid crystal and the adhesive, there is no adverse effect of the adhesive on the liquid crystal, and high-quality display without alignment defects and long-term high reliability can be obtained.

Further, after injecting the liquid crystal from the liquid crystal injection port, a spacer is inserted into a groove provided in advance in at least a portion of the liquid crystal injection port, and the outer periphery of the spacer is further sealed with an adhesive to manufacture a liquid crystal display panel. Therefore, the liquid crystal injection port can be closed quickly and reliably, and the liquid crystal display panel described above can be manufactured at a high yield and at low cost. Further, the above effect can be suitably achieved when the liquid crystal injection port is formed wide and liquid crystal is injected in a short time.

[Brief explanation of the drawing]

FIGS. 1(A) to (E) are plan views showing some specific examples of the liquid crystal display panel of the present invention, and FIGS. 2(A) to (F) are plan views of FIGS. 1(A) to (E). A-A'B-B', c-c
FIG. 3 is a diagram showing a conventional liquid crystal display panel, and FIG. ) is (a) F- in the figure
It is a sectional view along the F' line. 11.12...Substrate 13...Sealing material 14...Liquid crystal 15...Liquid crystal injection port 16...Groove 17...・・・
Spacer 18...Adhesive

Claims (2)

[Claims] (1) In a liquid crystal display panel in which liquid crystal injected from a liquid crystal injection port is interposed between a pair of substrates having electrodes, a groove is provided in at least a part of the liquid crystal injection port, and a spacer is installed in the groove. , a liquid crystal display panel characterized in that its outer periphery is sealed with an adhesive. (2) A sealing material is provided on the outer periphery between a pair of substrates having electrodes to form a gap, and after injecting liquid crystal into the gap from a liquid crystal injection port, a sealing material is provided in advance in at least a part of the liquid crystal injection port. 1. A method for manufacturing a liquid crystal display panel, which comprises inserting a spacer into a groove, and further sealing the outer periphery of the spacer with an adhesive.