JP2003280013A - Liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To completely harden a sealing material made of photocuring resin charged in a liquid crystal injection hole up to its inner part efficiently with a smaller amount of irradiation light. <P>SOLUTION: Light reflecting layers 9 and 10 are provided on the internal surfaces of both substrates 1 and 2 at the liquid crystal injection hole 7a. When liquid crystal injection holes 7a are sealed, the sealing materials 12a are charged in the respective liquid crystal injection holes 7a of a plurality of liquid crystal display elements, and the plurality of liquid crystal elements are arranged upright by matching the positions of the respective liquid crystal injection holes 7a, which are irradiated with ultraviolet rays. The ultraviolet rays incident on the sealing materials 12a travel inward while absorbed by the sealing materials 12a and at this point, ultraviolet rays incident on the light reflecting layers 9 and 10 are reflected in the inside sealing materials 12a to contribute to the curing of the sealing material 12a without being scattered out from the substrates 1 and 2. Consequently, the sealing material 12a made of the photosetting resin supplied into the liquid crystal injection hole 7a is completely cured up to its inner part. <P>COPYRIGHT: (C)2004,JPO

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 device, and more particularly to a structure of a liquid crystal injection port in a liquid crystal display device.

[0002]

2. Description of the Related Art In a conventional liquid crystal display device, two transparent substrates each having an electrode and an alignment film provided in respective display areas on opposite surfaces form a liquid crystal injection port arranged outside the display area. Laminated through a rectangular frame-shaped sealing material having a cutout portion, liquid crystal is injected between both substrates inside the sealing material through a liquid crystal injection port formed of the cutout portion,
There is one in which the liquid crystal inlet is sealed with a sealing material made of a photocurable resin.

Next, a conventional liquid crystal injection port sealing step in such a liquid crystal display element will be described. First, after applying the liquid crystal injection process, a sealing material made of a photo-curing resin is applied to the liquid crystal injection ports of both transparent substrates by a dispenser method or the like, and back pressure due to capillary phenomenon or liquid crystal volume change is used. The applied sealing material is introduced into the liquid crystal injection port, and thereafter, ultraviolet rays are irradiated to cure the sealing material filled in the liquid crystal injection port to seal the liquid crystal injection port.

In the ultraviolet irradiation step, a plurality of liquid crystal display elements are arranged upright with their respective liquid crystal injection port positions aligned, and ultraviolet rays are collectively irradiated toward the liquid crystal injection ports, so that each liquid crystal display element is exposed. The encapsulating material supplied into the liquid crystal injection port is cured together.

[0005]

As described above, in the above-described conventional liquid crystal injection port sealing step, a plurality of liquid crystal display elements are arranged with their respective liquid crystal injection port positions aligned, and the juxtaposed direction is directed toward the liquid crystal injection ports. And are radiating ultraviolet rays all at once from the right angle direction. The ultraviolet rays that have entered the encapsulating material enter the back side while being absorbed by the encapsulating material some of them.
At that time, a large amount of ultraviolet rays are incident on the inner wall surfaces of both substrates of the liquid crystal injection port and the wall surface formed of the end surface of the notch portion of the sealing material. Of the ultraviolet rays incident on this wall surface, the ultraviolet rays reflected to the side of the sealing material contribute to the curing of the sealing material, but also pass through the wall surface of other transparent substrates such as glass, and these substrate wall surfaces and sealing materials. The ultraviolet rays absorbed by the wall surface of the glass do not contribute to the curing of the sealing material. In particular, when both the pair of opposing substrates are transparent substrates, the amount of light diffused from the wall surfaces of the transparent substrates is larger, and the utilization efficiency of the irradiation light is significantly reduced. As a result, the ultraviolet rays may not sufficiently reach the inner part of the sealing material filled in the liquid crystal inlet, and the uncured component may remain in the inner part of the sealing material. In such a case, the uncured component in the inner part of the encapsulant is dissolved in the liquid crystal in the liquid crystal display element, and the dissolved material is arranged in the display area in the liquid crystal display element. If it enters the area, an alignment error occurs and display quality deteriorates. Here, in order to prevent the uncured material of the sealing material only, it is sufficient to irradiate with excessive ultraviolet rays, but excessive irradiation of ultraviolet rays may deteriorate the liquid crystal, and the irradiation light amount of ultraviolet rays should be as low as possible. The less the better.
An object of the present invention is to ensure that a sealing material made of a photocurable resin filled in a liquid crystal injection port is efficiently and reliably cured to a deeper portion with a smaller irradiation light amount, and a display defect due to uncured sealing material occurs. It is to provide a liquid crystal display device which does not exist.

[0006]

According to a first aspect of the present invention, there is provided a notch in which two substrates each provided with an electrode and an alignment film form a liquid crystal injection port at least at one position. And a liquid crystal is injected between the substrates inside the seal material through a liquid crystal injection port formed of the cutout portion, and the liquid crystal injection port is a photocurable resin. A liquid crystal display element which is sealed with a sealing material consisting of, wherein a light reflection layer is provided on at least a part of the wall surface of the liquid crystal inlet. According to this invention, when the sealing material made of a photo-curable resin filled in the liquid crystal inlet is cured by irradiating light such as ultraviolet rays, the light reflection layer disposed on the wall surface of the liquid crystal inlet is used. Irradiation light that has entered the encapsulation material can be diffused to the outside and reflected without being absorbed by the wall surface, so that the irradiation light can be used efficiently and efficiently to reach deep inside the encapsulation material. Therefore, it is possible to reliably cure the encapsulating material made of the photo-curable resin filled in the liquid crystal injection port to a deeper portion with a smaller irradiation light amount. In this case, as described in claim 2,
It is preferable that the two substrates are transparent substrates, and the light-reflecting layers are provided on both opposing substrate surfaces of the liquid crystal injection port. Further, as described in claim 3, the substrate opposite to the display surface side of the two substrates is made incident on the surface facing the display surface side substrate through the display surface side substrate. An external light reflection layer for reflecting external light transmitted through the liquid crystal may be provided. In this case, claim 4
As described above, it is preferable that the light reflection layer and the external light reflection layer are simultaneously formed of the same material.

[0007]

1 is a plan view of a main portion of a liquid crystal display device as an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA of FIG. . In the liquid crystal display element of the present embodiment, a segment substrate 1 and a common substrate 2 made of transparent glass, a resin film or the like are arranged so as to face each other.

A plurality of segment electrodes 3 are provided on the inner surface of the segment substrate 1 (the surface facing the common substrate 2).
An alignment film 4 is provided so as to cover these. A plurality of common electrodes 5 are provided on an inner surface of the common substrate 2 (a surface facing the segment substrate 1), and an alignment film 6 is provided so as to cover the common electrodes 5.

The substrates 1 and 2 have a liquid crystal inlet 7a.
And a sealing material 7 having a rectangular frame shape. In this state, the electrodes 3 and 5 are orthogonal to each other, and the intersection facing portions form a plurality of pixels arranged in a matrix. These pixels and both alignment films 4 and 6 are arranged inside a sealing material 7 in a rectangular display region 8 surrounded by a chain line.

Light reflecting layers 9 and 10 are provided on the inner surfaces of the transparent substrates 1 and 2 at the liquid crystal injection port 7a. The light reflection layers 9 and 10 are specular reflection layers formed by patterning a highly reflective metal film made of aluminum or the like formed by a sputtering method, or diffusing light by a method such as making the surface uneven. It consists of a diffuse reflection layer that reflects light. The depth of each of the light reflection layers 9 and 10 is the same as the depth of the liquid crystal injection port 7a.
It may be a little longer as shown in FIG. Further, the areas of the light reflection layers 9 and 10 may be slightly larger than the areas of the liquid crystal injection ports 7a on both the substrates 1 and 2 in FIG. The light reflection layers 9 and 10 are not limited to the specular reflection layer and the diffuse reflection layer, and may be any layer as long as the ratio of absorbing incident light is small.

A liquid crystal 11 is injected between the alignment films 4 and 6 of both substrates 1 and 2 inside the sealing material 7 through a liquid crystal injection port 7a. The liquid crystal injection port 7a is sealed with a sealing material 12 made of a photocurable resin. It should be noted that one side of the segment substrate 1 is projected from the common substrate 2, and a plurality of connection terminals (segment terminal and common Terminal) is provided.

Next, a liquid crystal injection port sealing step in this liquid crystal display device will be described with reference to FIG. First, a liquid crystal injection port 7a of a plurality of liquid crystal display elements after the liquid crystal injection step is applied with a sealing material made of a photo-curing resin by a dispenser method or the like, and is applied by utilizing a capillary phenomenon or back pressure. The sealing material 12a is sufficiently penetrated to the inner side of the liquid crystal injection port 7a.

Next, with the plurality of liquid crystal display elements standing in parallel between the liquid crystal display elements with the spacers 13 in between, the positions of the liquid crystal inlets 7a are aligned, for example, on the upper side, and the sealing material 12a is filled. Ultraviolet rays (or visible light) are collectively radiated from the upper side toward the liquid crystal injection ports 7a thus formed. In this case, the ultraviolet rays are emitted from the upper side in the direction perpendicular to the direction in which the liquid crystal injection ports 7a are arranged.

The ultraviolet rays that have entered the sealing material 12a in the liquid crystal inlet 7a enter the interior while being absorbed by the sealing material 12a, some of which inside the liquid crystal inlet 7a. There are many incident ultraviolet rays. In particular,
Ultraviolet rays that enter the liquid crystal injection port 7a not obliquely from above but obliquely above have a larger incidence angle (larger inclination) and have a greater proportion of incidence on the wall surface. However, in the liquid crystal display element according to the present invention, as described above, the light reflection layers 9, 10 are formed on the wall surfaces of the substrates 1, 2 in the liquid crystal inlet 7a.
Since the ultraviolet rays incident on these are installed, the ultraviolet rays incident on these are not scattered or absorbed and are not absorbed inside (the sealing material 12a
The light is reflected to the side) and is effectively used for curing the sealing material 12a without waste.

As described above, the ultraviolet rays are made to enter the sealing material 12a filled in the liquid crystal injection port 7a not only from the front direction but also from a wide incident angle range, and the substrate 1,
The sealing material 12a can be efficiently used for curing without being scattered to the outside from the wall surface of No. 2 or absorbed by the wall surface. Therefore, it is possible to sufficiently reach the inner part of the encapsulating material 12a with ultraviolet rays with the amount of ultraviolet irradiation light suppressed so as not to deteriorate the liquid crystal. As a result, the sealing material 12 made of the photo-curable resin filled in the liquid crystal injection port 7a.
a is completely hardened to the inner part. This allows
It is possible to reliably prevent the alignment abnormality of the liquid crystal molecules due to the uncured sealing material 12a, and it is possible to reliably prevent the deterioration of the display quality due to the alignment abnormality.

It should be noted that some of the ultraviolet rays emitted toward the aligned liquid crystal inlets 7a are adjacent to each other.
Although it is incident on the end faces of the substrates 1 and 2 between a, the ultraviolet light incident on the end faces of the substrates 1 and 2 is almost absorbed if the substrate is made of a material that absorbs ultraviolet light to prevent liquid crystal deterioration. Even if it is not, the ratio of incidence from the substrates 1 and 2 to the light reflection layers 9 and 10 on the wall surface of the liquid crystal inlet 7a is extremely small. Therefore, the provision of the light absorption layers 9 and 10 does not delay the curing of the sealing material 12a.

Next, FIG. 4 shows a sectional view similar to FIG. 2 of a liquid crystal display element as another embodiment of the present invention. This liquid crystal display element is a reflection type (or a semi-transmissive reflection type), and is different from the embodiment shown in FIG. 2 in that the light reflection layer 9 is provided only on the inner surface of the segment substrate 1 at the liquid crystal injection port 7a. It is not provided on the common substrate 2 side, and an external light reflection layer (or a semi-transmissive reflection layer) 13 for reflecting external light and an interlayer insulating film 14 are provided on the inner surface of the segment substrate 1 for interlayer insulation. That is, the segment electrode 3 and the alignment film 4 are provided on the film 14. In addition, in this embodiment, the segment substrate 1 on the side opposite to the display side (observation side), that is, the rear side may not be transparent. Even when the segment substrate 1 is opaque, some of the wall surface portion of the liquid crystal injection port 7a is absorbed when the light traveling through the sealing material 12a enters. Therefore, it is possible to prevent such absorption of light by disposing the light reflection layer 9 as in the present embodiment.

In this case, only the light reflection layer 9 provided on the inner surface of the liquid crystal injection port 7a of the segment substrate 1 reflects the ultraviolet rays incident on the sealing material 12a. Segment board 1
Since it can be prevented from passing through and escaping to the outside, the amount of irradiation light is increased by an amount commensurate with the amount of ultraviolet light passing through and dissipating through the common substrate 2 as compared with the case of the embodiment example of FIG. By doing so, it is possible to surely cure the encapsulating material, which is filled with the liquid crystal injection port 7a and is made of the photo-curable resin, to the inner part thereof.

In the case of the present embodiment, since the reflective layer 9 and the external light reflective layer 13 are provided on the inner surface of the segment substrate 1, these can be simultaneously formed by the same material. That is, a highly reflective metal film made of aluminum or the like is uniformly formed on the inner surface of the segment substrate 1 by the sputtering method, and the reflective layer 9 and the external light reflection layer 13 are provided at predetermined positions on the inner surface of the segment substrate 1. It may be patterned so as to be formed. Thereby, it is not necessary to increase the process for forming the reflective layer 9, and it is possible to avoid an increase in the number of manufacturing steps of the liquid crystal display element.

In each of the above embodiments, the light reflecting layer is provided only on the wall surface of the substrate at the liquid crystal inlet, but the invention is not limited to this, and the light reflecting layer may be provided on the wall surface of the sealing material. In this case, the irradiation light absorbed by the wall surface of the sealing material can also be reflected to be used for curing the sealing material, and if a light reflection layer is provided on all the wall surfaces of the liquid crystal injection port, the sealing material The amount of light applied for curing can be significantly reduced.

Further, the case where the present invention is applied to a simple matrix type liquid crystal display element has been described, but the present invention is not limited to this, and the present invention can be applied to other active matrix type liquid crystal display elements. Further, in the case of a reflective (or semi-transmissive reflective) liquid crystal display element, when one electrode is also used as a reflective electrode (or a semi-transmissive reflective layer), the reflective electrode and the reflective electrode shown in FIG. The layer 9 may be simultaneously formed of a reflective metal material such as aluminum.

[0022]

As described above, according to the present invention, when the encapsulating material composed of the photo-curable resin filled in the liquid crystal injection port is irradiated with light such as ultraviolet rays to be cured, the liquid crystal injection port The light-reflecting layer placed on the wall reflects the incident light that has entered the encapsulating material without escaping it to the outside, and efficiently uses the irradiated light to reach the inner part of the encapsulating material sufficiently. Therefore, it is possible to surely cure the encapsulating material, which is filled with the liquid crystal injection port and is made of the photo-curable resin, to the inner portion thereof with a smaller amount of irradiation light.

[Brief description of drawings]

FIG. 1 is a plan view of a main part of a liquid crystal display element as an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a partial cross-sectional view shown for explaining a liquid crystal injection port sealing step.

FIG. 4 is a sectional view of a liquid crystal display element as another embodiment of the present invention, similar to FIG.

[Explanation of symbols]

1 segment board 2 Common board 3 segment electrode 4 Alignment film 5 Common electrode 6 Alignment film 7 Seal material 7a Liquid crystal inlet 8 display areas 9, 10 Light reflection layer 11 liquid crystal 12 Sealant 12a sealing material 13 External light reflection layer

Claims (4)

[Claims] 1. Two substrates, each provided with an electrode and an alignment film, are bonded to each other via a frame-shaped sealing material having a cutout portion for forming a liquid crystal injection port at at least one location,
A liquid crystal display element in which liquid crystal is injected between the two substrates inside the sealing material through a liquid crystal injection port formed of the cutout portion, and the liquid crystal injection port is sealed with a sealing material made of a photocurable resin. A liquid crystal display device, wherein a light reflection layer is provided on at least a part of a wall surface of the liquid crystal injection port. 2. The invention according to claim 1, wherein
A liquid crystal display element, wherein the one substrate is a transparent substrate, and the light reflection layer is provided on both opposing substrate surfaces in the liquid crystal injection port. 3. The invention according to claim 1, wherein a back surface of the two substrates opposite to the display surface is provided on a surface of the back surface opposite to the display surface. A liquid crystal display element, wherein an external light reflection layer for reflecting external light that has entered through the substrate on the display surface side and transmitted through the liquid crystal is provided. 4. The liquid crystal display element according to claim 3, wherein the light reflection layer and the external light reflection layer are formed of the same material at the same time.