JP2000314893A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent changes in the gap width in a display region even when a peripheral sealing material swells by moisture absorption by forming a region having no distribution part of intra-plane spacers in a part or whole circumference of a nondisplay region. SOLUTION: An alignment film is formed on a transparent electrode of each transparent electrode substrate 2, 3 and subjected to a rubbing treatment. For example, intra-plane spacers 5 are distributed on a first transparent electrode substrate 2 of the two substrates, but the intra-plane spacers 5 are not distributed in the nondisplay region 4b by covering with a mask made of a metal plate. Thus, a region having no distribution of the intra-plane spacers is formed as a flexible buffer area in the nondisplay region 4b. The region 7 having no distribution part of intra-plane spacers is preferably formed along the whole peripheral sealing material 6. Even when the peripheral sealing material 6 swells by absorption of moisture to generate force to open the gap between substrates in the sealing region, the region 7 having no distribution of intra-plane spacers is bent to absorb the force. Therefore, the gap width in the display part 4a is hardly influenced.

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 liquid crystal display device having a buffer area for preventing a temporal change of a gap width sandwiching a liquid crystal layer.

[0002]

2. Description of the Related Art A liquid crystal display element is turned on by applying a predetermined driving voltage between transparent electrodes opposed to each other with a liquid crystal layer interposed therebetween. The driving voltage is, for example, dependent on the specific resistance and gap width of the liquid crystal. Dependencies. Since these factors are different for each product, when the product is shipped, the liquid crystal drive voltage is adjusted to the optimal drive voltage for each model.

[0003]

The specific resistance of the liquid crystal has been decreasing year by year due to the recent improvement in liquid crystal refining technology and the performance of the alignment film, but the gap width for sandwiching the liquid crystal layer has been reduced. There is still a problem with the fluctuation over time.

That is, an epoxy adhesive has been used consistently as a peripheral sealing material for bonding a pair of transparent electrode substrates. Epoxy adhesive is a few%
It is water-absorbing to some extent, and may swell due to water absorption. Moreover, the swelling amount tends to increase with time.

In the cell gap into which liquid crystal is injected, an in-plane spacer for holding the gap is inserted. The in-plane spacer is used only for maintaining the parallelism when a pair of transparent electrode substrates are bonded. In many cases, resin beads that are deformed by losing a strong force are used.

[0006] Since the peripheral sealing material itself compresses and holds the pair of transparent electrode substrates in a compressed state, once moisture is absorbed and swells, the holding force is released and an unexpectedly large reaction force is released. And the gap width in the central portion of the panel is relatively narrowed, thereby causing a shift in the optimal drive voltage adjusted at the time of product shipment.

In order to solve this problem, it is only necessary to provide a liquid crystal drive voltage adjusting means such as an electronic volume for each product. In such a case, it is obvious that the number of parts and the accompanying number of parts are increased. It is not preferable because the number of assembling steps increases. Not only that, but an extra burden is imposed on the user for adjustment, and furthermore, the user may be distrusted with the display quality.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to make the gap width of the display area fluctuate even if the peripheral sealing material swells due to moisture absorption. An object of the present invention is to provide a liquid crystal display element that does not cause such a problem.

In order to achieve the above object, the present invention provides a method of forming a pair of transparent electrode substrates each having a display region in which a transparent electrode for display is formed, and disposing an in-plane spacer for maintaining a gap between the transparent electrode substrates. A liquid crystal is sealed in the cell gap of the transparent electrode substrate via a peripheral seal material, and a non-display area not involved in display is provided between each display area of the transparent electrode substrate and the peripheral seal material. In a liquid crystal display element provided in a frame shape with a predetermined width,
The non-display area is characterized in that an in-plane spacer non-dispersed portion, on which the in-plane spacer is not substantially dispersed, is provided over a part or the entire circumference.

In the present invention, the non-scattering portion of the in-plane spacer is a buffer area against swelling of the peripheral sealing material. That is, since the in-plane spacer non-scattering portion does not have the support of the in-plane spacer, the portion is more easily bent than other portions where the in-plane spacer is sprayed.

Therefore, even if the peripheral seal material swells due to moisture absorption and a force is generated in the seal portion to push between the substrates, the in-plane spacer non-scattering portion is bent and the force is absorbed. In addition, a change in the gap width of the display area is prevented.

The number of in-plane spacers to be scattered in the non-in-plane spacer non-scattering portion is ideally "0". However, even if the in-plane spacers are scattered within a range where an appropriate flexibility can be obtained. Often, the present invention also treats such a case assuming that the in-plane spacer is not substantially dispersed.

When the transparent electrode substrate is made of a glass substrate,
According to a preferred aspect of the present invention, the thickness of a portion corresponding to at least the non-scattering portion of the in-plane spacer of both substrates or one of the transparent electrode substrates is 0.1 to 0.4 mm.

According to this, the in-plane spacer non-scattering portion is more easily bent. Instead of reducing only the thickness of the non-spreading portion of the in-plane spacer, the thickness may be reduced over one of the transparent electrode substrates. The method for reducing the plate thickness may be either chemical etching or physical polishing.

When a plastic substrate or a film substrate is used as the transparent electrode substrate, it is not necessary to further reduce the thickness because the substrate itself is flexible. Good.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a first embodiment of the present invention. FIG. 1 is a plan view of this embodiment, and FIG. 2 is a sectional view taken along line AA of FIG.

The liquid crystal display device 1 includes first and second two transparent electrode substrates 2 and 3. In this embodiment, each of the transparent electrode substrates 2 and 3 is made of a glass substrate having a thickness of 0.7 mm.
a to 3c are continuously provided.

Each of the transparent electrode substrates 2 and 3 has a display area 4a and a non-display area 4b. The display area 4a occupies substantially the center of the substrate, and although not shown, the display area 4a includes, for example, ITO (indium).
A transparent electrode for display composed of tin oxide) is formed in a predetermined pattern.

The non-display area 4b is provided in a frame shape with a predetermined width so as to surround the display area 4a. In the non-display area 4b, an extraction electrode of a transparent electrode for display is formed, and therefore, the non-display area 4b does not participate in display.

In each of the transparent electrode substrates 2 and 3, an alignment film (not shown) is formed on the transparent electrode, and the alignment film surface is rubbed. Then, for example, the in-plane spacer 5 is dispersed on one of the first transparent electrode substrates 2 side.
At this time, a mask made of, for example, a metal plate is applied to the non-display area 4b, and the in-plane spacer 5 is scattered only in the display area 4a, and the in-plane spacer 5 is not substantially scattered in the non-display area 4b.

On the other side of the second transparent electrode substrate 3,
A peripheral sealing material 6 is applied around the non-display area 4b, and the first and second transparent electrode substrates 2 and 3 are bonded to each other via the peripheral sealing material 6. Note that an epoxy-based adhesive may be used for the peripheral sealing material 6 as in the related art.

As a result, the in-plane spacer non-scattering portion 7 is formed in the non-display area 4b as a buffer area that is easily bent.
It can be said that the in-plane spacer non-scattering portion 7 is preferably formed along the entire periphery of the peripheral sealing material 6, but in this embodiment, as shown in FIG. And two of them are arranged.

In this embodiment, a groove 7a is formed on the first transparent electrode substrate 2 side in order to impart better flexibility to the in-plane spacer non-scattering portion 7. That is, the thickness of the portion of the in-plane spacer non-spraying portion 7 is reduced by the groove 7a, but the remaining thickness is reduced to 0.1.
The thickness is preferably 1 to 0.4 mm.

The groove 7a may be formed by either chemical etching or physical polishing. Further, instead of partially reducing the thickness by the groove 7a as in this embodiment, the entire substrate may be made 0.1 to 0.4 mm thick. It may be thinned. After thinning, the polarizing plates 8 and 8 are adhered to the transparent electrode substrates 2 and 3 respectively.

According to this configuration, even if the peripheral sealing material 6 swells due to moisture absorption and a force is generated at the sealing portion to push the gap between the substrates, the in-plane spacer non-scattering portion 7 bends. , Its power is absorbed. Therefore, the gap width of the display section 4a is hardly affected. In addition, the in-plane spacer non-scattering portion 7 is in the non-display area 4b.
, It does not hinder the display.

The amount of swelling of the currently used epoxy resin-based peripheral sealing material due to moisture absorption is about +0.2 μm, and the variation in the gap width of the display area caused by this swelling may be −0.05 μm at the maximum.

As one calculation, the display area is 30 mm ×
In the case of 40 mm, if the gap width is reduced by 0.05 μm, the reduced volume is 0.06 mm ³ . As described above, if the in-plane spacer non-scattering portion is provided as a buffer area and the flexibility reduces the gap width at the same portion on average by 0.6 μm, a buffer area of 100 mm ² is required. . If this is distributed over four sides,
25 mm ³ per piece, 30 mm long and about 1 mm wide.

[0028]

Example << Example 1 >> 0.7 m as a transparent electrode substrate
An m-thick soda glass was used. After sequentially forming a transparent electrode and an alignment film on each of them, and performing a rubbing process, a metal mask is placed on the non-scattering portion of the non-display region where the planned in-plane spacers are to be spread, and the other portions are averaged. About 10,000 resin-made in-plane spacers having a particle size of 6 μm were sprayed per square cm. The total area including the display area and the non-display area is 30 × 40 mm = 1200 mm
² , on the other hand, the in-plane spacer non-scattering portions are formed at two locations along two opposing sides of the peripheral sealing material with dimensions of 26 mm (length) × 3 mm (width) as shown in FIG. did. Then, after the peripheral sealing material was applied to the other glass substrate, the two glass substrates were overlapped and thermocompression bonded to harden the peripheral sealing material. After injecting the liquid crystal into the cell gap, the entire glass substrate on one side was cut by 5 mm by chemical etching to make the thickness 0.2 mm. Finally, a polarizing plate was attached to both glass substrates. When this liquid crystal display element was left in a high-temperature and high-humidity atmosphere at 80 ° C. and a relative humidity of 90% for 200 hours, a humidity resistance test was performed. However, the maximum gap variation in the display area was -0.02 μm. As a result, the fluctuation rate of the optimum drive voltage Vd was only 0.5%.

Comparative Example 1 In particular, a liquid crystal display device was produced in the same manner as in Example 1 without providing an in-plane spacer non-scattering portion in a non-display area and without thinning the glass substrate on one side. . This liquid crystal display device was subjected to the same moisture resistance test as described above. As a result, the gap fluctuation in the peripheral sealing material was 0.17 μm in the + direction due to moisture absorption of the sealing material.
The maximum gap variation in the display area was -0.06 [mu] m. As a result, the fluctuation rate of the optimum drive voltage Vd is 1.4.
% Has been reached.

[0030]

As described above, according to the present invention,
In the non-display area provided between the display area and the peripheral seal material, an in-plane spacer non-dispersed portion in which the in-plane spacer is not substantially dispersed is provided over a part or the entire circumference of the non-display area. Thus, even if the peripheral seal material swells due to moisture absorption, it is possible to prevent the gap width of the display region from fluctuating.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display element 2, 3 Transparent electrode substrate 4a Display area 4b Non-display area 6 Peripheral seal material 7 In-plane spacer non-scattering part 7a Groove 8 Polarizing plate

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H089 LA07 LA10 NA09 QA14 SA01 TA01 2H090 HA02 JA03 JA15 LA02 5C094 AA03 AA36 AA37 AA53 AA54 BA43 DA12 EA05 EB02 EC03 FA01 FA02 FB01 FB15 GB01 JA08

Claims (2)

[Claims] 1. A pair of transparent electrode substrates each having a display area in which a display transparent electrode is formed, and an in-plane spacer for maintaining a gap is disposed between the transparent electrode substrates. In addition, liquid crystal is sealed in the cell gap, and a non-display area not involved in display is provided in a frame shape with a predetermined width between each display area of the transparent electrode substrate and the peripheral sealing material. In the liquid crystal display element, the non-display area is provided with an in-plane spacer non-dispersion part in which the in-plane spacer is not substantially dispersed, over a part or the entire circumference thereof. element. 2. In the case where each of the transparent electrode substrates is made of a glass substrate, the thickness of at least a portion corresponding to at least the non-scattering portion of the in-plane spacer of both substrates or one of the transparent electrode substrates is 0.1 to 0.1. 2. The liquid crystal display device according to claim 1, wherein the thickness is 0.4 mm.