JPH112825A - Manufacture of liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the liquid crystal display device of superior display quality without using any slit light shield mask by hardening a sealant by irradiation with light whose specific wavelength range of ultraviolet rays decomposing or deteriorating a liquid crystal composition is cut. SOLUTION: When the liquid crystal composition 5 is injected into a liquid crystal cell 3 and the sealing hole 4 is hardened with the ultraviolet-ray setting sealant 6, an optical fiber type ultraviolet-ray lamp 9 is used. The ultraviolet rays 7 emitted by the ultraviolet-ray lamp 8 irradiates the sealant 6 from an irradiation hole 9b through an optical fiber 9a. At this time, the optical fiber type ultraviolet-ray lamp 9 such light emission wavelength spectrum characteristics that the light emission of the ultraviolet rays 7 is less in the short-wavelength range than in any other wavelength range. Consequently, the liquid crystal composition 5 which is decomposed or deteriorated owing to irradiation with the ultraviolet rays 7 in the short-wavelength range can be prevented from being decomposed or deteriorated in the hardening process of the sealant 6 by irradiating the sealant with the ultraviolet rays through the optical fiber 9a which is small in the propagation of the ultraviolet rays 7 in the short-wavelength range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device having a sealing material of an ultraviolet curable material.

[0002]

2. Description of the Related Art Conventionally, a method of manufacturing a liquid crystal display device is disclosed in Japanese Patent Application Laid-Open No. Hei 7-333624.

FIG. 6 shows a manufacturing process of a conventional liquid crystal display device. As shown in FIG. 6 (a), the liquid crystal cell 3 includes a substrate 1a and a substrate 1b each having electrodes, and a sealing material 2 provided around the display area of the substrate except for the sealing port 4. It is composed by bonding.

[0006] As shown in FIG. 6 (b), a liquid crystal composition 5 is injected from a sealing port 4 of a liquid crystal cell 3, and then, as shown in FIG. 6D, the uncured sealing material 6 is irradiated with ultraviolet rays 7 from an ultraviolet lamp 8 as shown in FIG. 6D, and the sealing material is sealed as shown in FIG. The liquid crystal display device in which 6 is cured is completed.

[0005]

In such a conventional method of manufacturing a liquid crystal display device, the energy of a specific wavelength region of the ultraviolet light 7 in the curing step of the sealing material causes the liquid crystal composition 5 to be decomposed or deteriorated. Thus, there is a problem of a display failure of the liquid crystal display device due to a decrease in voltage holding ratio or a decrease in specific resistance.

Therefore, conventionally, when irradiating the ultraviolet rays 7, a light shielding mask with a slit is used in order to prevent the ultraviolet rays 7 from being irradiated to parts other than the sealing material. An object of the present invention is to provide a liquid crystal display device having excellent display quality by preventing display defects due to decomposition or deterioration of a liquid crystal composition during a curing step of a sealing material without using a light-shielding mask with a slit. Aim.

[0007]

According to the present invention, when the sealing material is cured, the sealing material is cured by irradiating light having a specific wavelength region of ultraviolet rays which decomposes or degrades the liquid crystal composition. .

According to the method of manufacturing a liquid crystal display device of the present invention, display defects due to decomposition or deterioration of the liquid crystal composition can be prevented without using a light-shielding mask with a slit.
A liquid crystal display device having excellent display quality can be obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is characterized in that, when a liquid crystal is put in a liquid crystal cell and the sealing opening is sealed with an ultraviolet curing type sealing material, the liquid crystal in the ultraviolet wavelength region is filled with the liquid crystal. A method of manufacturing a liquid crystal display device, in which light having a specific wavelength region that has an adverse effect is removed is applied to the sealing material to cure the sealing material, and the liquid crystal composition is decomposed during a curing step of the sealing material. Alternatively, deterioration can be prevented.

According to the second aspect of the present invention, when a liquid crystal is put into a liquid crystal cell and the sealing port is sealed with an ultraviolet-curable sealing material, the liquid crystal in the ultraviolet wavelength region is adversely affected. A method for manufacturing a liquid crystal display device, in which the sealing material is cured by irradiating the sealing material with light having a wavelength region removed in an inert gas atmosphere. Can be prevented from decomposing or deteriorating, and the surface curability of the sealing material can be promoted.

According to a third aspect of the present invention, the sealing material is irradiated with light from an ultraviolet light source through an optical fiber, and a wavelength in a specific wavelength region is cut by the optical fiber. 2. A method for manufacturing a liquid crystal display device according to any one of the above items 2.

According to a fourth aspect of the present invention, the sealing material is irradiated with light from an ultraviolet irradiation light source through a filter, and a wavelength in a specific wavelength region is cut by the filter. 2. A method for manufacturing a liquid crystal display device according to any one of the above items 2.

According to a fifth aspect of the present invention, there is provided the method for manufacturing a liquid crystal display device according to any one of the first to fourth aspects, wherein the specific wavelength region is set to a short wavelength region of the ultraviolet wavelength region. It is characterized by the following.

According to a sixth aspect of the present invention, when the liquid crystal is charged into the liquid crystal cell and the sealing opening is sealed with an ultraviolet curing type sealing material, the sealing material is irradiated with ultraviolet rays in an inert gas atmosphere. The method is a method for manufacturing a liquid crystal display device in which the sealing material is cured by promoting the surface curing property of the sealing material, thereby shortening the curing time of the sealing material. Decomposition or deterioration of the composition can be reduced.

Hereinafter, a method for manufacturing a liquid crystal display device according to the present invention will be described based on specific embodiments. (Embodiment 1) As shown in FIG. 1, a liquid crystal composition 5 is injected into a liquid crystal cell 3, and a sealing port 4 is filled with an ultraviolet-curing sealing material 6.
In curing, the optical fiber type ultraviolet lamp 9 is used.

Ultraviolet light 7 emitted from an ultraviolet lamp 8 as an ultraviolet irradiation light source is applied to the sealing material 6 from an irradiation port 9b via an optical fiber 9a. FIG. 2 shows the emission wavelength spectrum characteristics of the optical fiber type ultraviolet lamp 9 at this time.

As shown in FIG. 2, the emission wavelength spectrum characteristic of the optical fiber type ultraviolet lamp 9 is such that at a wavelength of about 300 nm or less, the specific energy value irradiated by the ultraviolet ray 7 is about 5 nm.
0% or less, and the emission of the ultraviolet rays 7 is smaller in the short wavelength region than in other wavelength regions.

As described above, in the case of a liquid crystal composition which is decomposed or degraded by irradiation of the ultraviolet ray 7 in the short wavelength region, the ultraviolet ray is irradiated through the optical fiber 9a through which the ultraviolet ray 7 in the short wavelength region hardly passes. It is possible to prevent the liquid crystal composition 5 from decomposing or deteriorating during the step of curing the sealing material.

(Embodiment 2) As shown in FIG. 3, when the liquid crystal composition 5 is injected into the liquid crystal cell 3 and the sealing port 4 is sealed with the ultraviolet curing type sealing material 6, the ultraviolet cut filter 10 is used. use.

As an ultraviolet irradiation light source, an ultraviolet lamp 8, for example, an ultraviolet ray 7 irradiated by a straight tube type high pressure mercury lamp.
Cures the sealing material 6 via an ultraviolet cut filter 10 that cuts a specific wavelength region.

As shown in FIG. 4, the transmitted light wavelength spectrum characteristic of the ultraviolet cut filter cuts a wavelength of about 300 nm or less in an ultraviolet wavelength region.
From the above, in the case of the liquid crystal composition 5 which is decomposed or deteriorated by irradiation of the ultraviolet ray 7 in the short wavelength region, an ultraviolet lamp 8 containing a short wavelength component, for example, a straight tube type high pressure mercury lamp was used as an ultraviolet irradiation light source. Even in this case, the use of the ultraviolet cut filter 10 that cuts the short wavelength region of the ultraviolet light 7 can prevent the liquid crystal composition 5 from being decomposed or deteriorated during the curing step of the sealing material 6.

(Embodiment 3) In Embodiments 1 and 2, the sealing material is cured by irradiating ultraviolet rays in the air. However, as shown in FIG. When the composition 5 is injected and the sealing port 4 is sealed with an ultraviolet-curable sealing material 6, ultraviolet irradiation is performed in an inert gas, for example, a nitrogen atmosphere.

In a nitrogen atmosphere 11, the sealing material 6 is cured by ultraviolet rays 7 irradiated from an ultraviolet lamp 8 containing a short wavelength component as an ultraviolet irradiation light source. The ultraviolet curing type sealing material 6 is an anaerobic material (hardening is inhibited by oxygen existing around the sealing material 6).

According to an experiment using the sealing material 6 having anaerobic properties, the surface hardening time of the sealing material 6 at an atmospheric nitrogen concentration of 80% and an oxygen concentration of 20% is about 10 seconds,
When the nitrogen concentration became 95% and the oxygen concentration became 5%, the surface hardening time of the sealing material 6 was reduced to about 1 second.

As described above, since oxygen is blocked in the nitrogen atmosphere 11 and the surface curing property is promoted and the irradiation time of the ultraviolet ray 7 can be shortened, even when the ultraviolet lamp 8 containing a short wavelength component is used, The decomposition or deterioration of the liquid crystal composition 5 due to the irradiation of the ultraviolet ray 7 in the short wavelength region during the curing step of the sealing material 6 can be reduced.

In the case where the sealing material 6 described in the first and second embodiments is cured in an inert gas atmosphere, for example, a nitrogen atmosphere, the surface of the sealing material 6 is cured by a short ultraviolet ray 7. Since the energy in the wavelength region is achieved by exceeding the anaerobic property of the sealing material 6, the short-wavelength region of the ultraviolet light 7 is cut, so that the surface curability of the sealing material 6 decreases.
By blocking the oxygen in the nitrogen atmosphere 11, the surface curability of the sealing material 6 can be promoted, and the decomposition or deterioration of the liquid crystal composition 5 during the curing step of the sealing material 6 can be further prevented.

[0027]

As described above, according to the method for manufacturing a liquid crystal display device of the present invention, the irradiation of the ultraviolet rays to portions other than the sealing material is performed by removing the specific wavelength region of the ultraviolet rays which adversely affects the liquid crystal composition. Even if a light-shielding mask with a slit for preventing is not used, display defects due to decomposition or deterioration of the liquid crystal composition during the curing step of the sealing material can be eliminated, and ultraviolet rays can be irradiated in an inert gas atmosphere. Irradiation can promote the surface curability of the sealing material,
A liquid crystal display device having excellent display quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a structural sectional view of a liquid crystal cell using an optical fiber type ultraviolet lamp according to a first embodiment of the present invention.

FIG. 2 is an emission wavelength spectrum characteristic diagram of the optical fiber type ultraviolet lamp according to the first embodiment.

FIG. 3 is a structural sectional view of a liquid crystal cell using an ultraviolet cut filter according to Embodiment 2 of the present invention.

FIG. 4 is a transmission light wavelength spectrum characteristic diagram of the ultraviolet cut filter according to the second embodiment.

FIG. 5 is a structural cross-sectional view of a liquid crystal cell showing ultraviolet irradiation in a nitrogen atmosphere according to a third embodiment of the present invention.

FIG. 6 is a sectional view showing a manufacturing process of a conventional liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1a Substrate 1b Substrate 2 Sealing material 3 Liquid crystal cell 4 Enclosure port 5 Liquid crystal composition 6 Sealing material 7 Ultraviolet 8 Ultraviolet lamp 9 Optical fiber type ultraviolet lamp 9a Optical fiber 9b Irradiation port 10 Ultraviolet cut filter 11 Nitrogen atmosphere

Claims (6)

[Claims] When a liquid crystal is put into a liquid crystal cell and an enclosing opening is sealed with an ultraviolet-curable sealing material, light from which a specific wavelength region which adversely affects the liquid crystal in an ultraviolet wavelength region is removed is sealed. A method for manufacturing a liquid crystal display device in which a sealing material is cured by irradiating a material. 2. When the liquid crystal is filled in a liquid crystal cell and the sealing opening is sealed with an ultraviolet-curing type sealing material, light obtained by removing a specific wavelength region which adversely affects the liquid crystal in the ultraviolet wavelength region is removed by an inert gas. A method for manufacturing a liquid crystal display device, wherein the sealing material is cured by irradiating the sealing material in an atmosphere. 3. A sealing material is irradiated with light from an ultraviolet irradiation light source via an optical fiber, and a wavelength in a specific wavelength region is cut by the optical fiber.
The method for manufacturing a liquid crystal display device according to any one of the above. 4. The liquid crystal display device according to claim 1, wherein light from an ultraviolet irradiation light source is applied to the sealing material through a filter, and a wavelength in a specific wavelength region is cut by the filter. Manufacturing method. 5. The method for manufacturing a liquid crystal display device according to claim 1, wherein the specific wavelength region is set to a short wavelength region of an ultraviolet wavelength region. 6. A liquid crystal display in which a liquid crystal is put into a liquid crystal cell and the sealing port is sealed with an ultraviolet-curable sealing material, and the sealing material is cured by irradiating the sealing material with ultraviolet rays in an inert gas atmosphere. Device manufacturing method.