JPH04355727A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To obtain a panel having a uniform gap by adjusting the nonuniformtiy in the gap within the panel surface after the completion of the element. CONSTITUTION:Fine particles 6 made of a resin and fine particles 7 made of 'Nitinal(R)' alloy which is a shape memory alloy are dispersed between glass substrates 1 and 5 to form spacers. The point where a gap is small is heated by a soldering iron 10 to restore the 'Nitinal (R)' alloy to a spherical shape, by which the gap is increased and the intra-surface gap is uniformized.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display element using a liquid crystal composition.

0002

2. Description of the Related Art In liquid crystal display devices, maintaining a uniform distance between electrodes and substrates, or the so-called panel gap, with high precision plays an important role in determining the display performance of the device. For this reason, in the past, resin particles, glass particles, or glass fibers with an appropriate diameter were dispersed on one electrode substrate, and this electrode substrate and the opposing electrode substrate were bonded together to close the panel gap. Methods are being used to maintain uniformity. The dispersion density at this time is 200 to 30 per mm2 in the case of resin particles.
0 particles, and about 50 to 150 glass particles.

0003

[Problem to be solved by the invention] Using conventional technology,
Maintaining a uniform panel gap with high precision is generally not easy, and is especially difficult for large panels. The causes of uneven panel gap are:
It is conceivable that the spacers made of resin or glass may be deformed within the panel, or that the spacers may not be evenly distributed within the plane of the substrate. In particular, resin particles are easily deformed when electrode substrates are bonded together, and their shape is not restorable, so even if the panel gap is uneven within the substrate surface after the element is completed, conventional technology cannot , it was difficult to adjust the panel gap.

Non-uniformity in the panel gap leads to in-plane non-uniformity in the electro-optic properties of the device, causing display defects.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a liquid crystal display element that can adjust the non-uniformity of the panel gap within the substrate plane after the element is completed.

[0006]

In order to achieve this object, the present invention uses a shape memory alloy or a microcapsule encapsulating a liquid crystal composition as a spacer.

[0007]

[Operation] Shape memory alloys have the property that even if they are significantly deformed from a certain shape, they completely return to their original shape when the temperature reaches or exceeds the reverse transformation end temperature. When such an alloy is processed into a spherical shape, even if the alloy is deformed, it will return to its original spherical shape when heated to a temperature equal to or higher than the reverse transformation end temperature.

[0008] When the electrode substrates are bonded together, if the spacer containing the shape memory alloy is deformed, the panel gap becomes non-uniform within the plane of the substrates. Now, a spherical shape memory alloy is used together with spacers such as resin particles, glass particles, or glass fibers. At this time, if the panel gap after bonding the electrode substrates is non-uniform, if the area where the gap is small is locally heated from the outside, the deformed shape memory alloy will restore its spherical shape and the gap at that area will become larger. As a result, the gap within the substrate surface becomes uniform. Furthermore, even if a spherical shape memory alloy is compressed and deformed and used together with other spacers, the same effect as above can be obtained by locally heating the area where the gap is small from the outside.

In contrast to the above-described method of enlarging areas where the panel gap is small, in order to reduce areas where the panel gap is large, the following method is used.

When resin microcapsules are irradiated with laser light, the microcapsules absorb the laser light and melt and collapse. At this time, microcapsules containing a liquid crystal composition inside are used as spacers. When a laser beam is locally irradiated to a large gap area within the panel surface, the microcapsules at the irradiated area melt and collapse. As a result, the gap at the location where the laser beam is irradiated becomes smaller, and the gap within the substrate surface becomes uniform.

As is clear from the above, the advantage of the present invention is that unevenness in the panel gap can be made uniform by locally adjusting the panel gap within the substrate plane after bonding the electrode substrates, thereby reducing element defects. It's about letting people know.

0012

EXAMPLE 1 FIG. 1 shows a cross section of a liquid crystal display element according to a first example of the present invention. On the lower glass substrate 1, a transparent electrode 2 was deposited, then silicon oxide 3 was deposited as an insulating layer, and polyimide 4 was further applied as an alignment film. Silicon oxide 3 includes Nitinol alloy fine particles 7 and transparent electrode 2.
It has the effect of insulating each other. Similarly, a transparent electrode 2 and silicon oxide 3 were deposited on the upper glass substrate 5, and polyimide 4 was applied thereto. The polyimide 4 was rubbed with a nylon nonwoven fabric. Resin fine particles 6 with a diameter of 5 microns and nitinol alloy fine particles 7 with a diameter of 5 microns were dispersed as spacers on the lower glass substrate 1 subjected to the above operation. At this time, the Nitinol alloy fine particles 7 used were ones that had been compressively deformed from the beginning. Dispersion is 1m with a number ratio of 1:1
A total of 200 pieces were dispersed per m2. Note that the same effect can be expected even if the Nitinol alloy fine particles are dispersed in a spherical form. In addition, when a shape memory alloy whose surface is coated with a resin is compressed and deformed, the resin part and the polyimide 4 adhere to each other.
It can be expected to have the effect of suppressing the flow of the shape memory alloy on the substrate. Further, the same effect can be obtained by using glass particles or glass fibers instead of the resin particles. 9 is a liquid crystal composition.

The nitinol alloy used is a shape memory alloy and is designed to restore its spherical shape at 80°C. Note that the restoring temperature may be set to any temperature higher than the panel temperature when the element is used. After printing the sealing resin 8 on the upper glass substrate 5, it was bonded to the lower glass substrate 1 according to a conventional method. Thereafter, the variation in the gap within the panel surface was measured using a measuring device (TM-230N manufactured by Canon Inc.). Figure 2(a) shows the measurement results.

[0014] Using a soldering iron 10, the glass substrate at a location where the panel gap was small was heated to bring the temperature of the Nitinol alloy fine particles 7 to 80°C or higher. At this time, the Nitinol alloy fine particles 7 were restored to a spherical shape, and the non-uniformity of the gap was improved. FIG. 2(b) shows the in-plane gap distribution after heating.

(Embodiment 2) FIG. 3 is a sectional view of a resin microcapsule 11. Resin microcapsule 11
Its diameter is 5 microns. At this time, polyethylene resin was used as the resin. At this time, a liquid crystal material having the same composition as the liquid crystal composition 9 between the element substrates was used as the liquid crystal composition 12 inside the capsule.

FIG. 4 shows a cross-sectional view of the device. The same treatment as in Example 1 was performed on the upper glass substrate 1 and the lower glass 5. The resin microcapsule 11 described above was used as a spacer together with glass fine particles 13 having a diameter of 5 microns. Dispersion of spacers is 2:1, total 1 per 1mm2.
00 pieces were dispersed. CO in areas with large panel gaps.
2 laser beams 14 were irradiated. At this time, the resin microcapsules 11 melted and collapsed. As a result, the panel gap at the point irradiated with the CO2 laser beam 14 becomes smaller.
Gap unevenness has been improved. The polyethylene resin after disintegration did not deteriorate display quality. C
The in-plane distribution of the panel gap before and after irradiation with the O2 laser beam 14 is shown in FIG. 5(a) and FIG. 5(b), respectively.

[0017]

[Effects of the Invention] As described above, the present invention provides shape memory alloys,
Or, a resin microcapsule containing a liquid crystal composition inside is used as a spacer for a liquid crystal display element,
After the substrates are bonded together, the non-uniformity of the panel gap can be eliminated, and its practical value is extremely large.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a liquid crystal display element according to Example 1 of the present invention.

[Figure 2] (a) In-plane distribution diagram of panel gap before heating (b)
In-plane distribution map of panel gap after heating

[Figure 3] Example 2
Cross-sectional view of microcapsules

[Figure 4] Cross-sectional view of the liquid crystal display element of Example 2

[Figure 5] (a) In-plane distribution diagram of panel gaps before laser beam irradiation (b) In-plane distribution diagram of panel gaps after laser beam irradiation

[Explanation of symbols]

1 Lower glass substrate 2 Transparent electrode 3 Silicon oxide 4 Polyimide 5 Upper glass substrate 6. Resin fine particles 7 Nitinol alloy fine particles 8 Seal resin 9 Liquid crystal composition 10 Soldering iron 11 Resin microcapsule 12 Liquid crystal composition 13 Glass particles 14 CO2 laser light

Claims (4)

[Claims] 1. A liquid crystal display element comprising a liquid crystal composition and a spacer between a pair of electrode substrates, at least one of which is transparent, the spacer containing at least a shape memory alloy. 2. The liquid crystal display element according to claim 1, wherein at least a shape memory alloy that deforms from an arbitrary shape into a spherical shape due to temperature change is used as the spacer. 3. A liquid crystal display element having a liquid crystal composition and a spacer between a pair of electrode substrates, at least one of which is transparent, and wherein the spacer includes at least a spherical capsule containing the liquid crystal composition inside. . 4. The liquid crystal display element according to claim 3, wherein the spherical capsule is a resin capsule that melts and collapses upon absorption of laser light.