JPH0973096A - Liquid crystal display element manufacturing method - Google Patents

Abstract

(57) Abstract: A liquid crystal display device having excellent display quality can be obtained while using an ultraviolet curable resin for the sealing material 13. SOLUTION: A step of dropping a liquid crystal material on an opposing surface of one of a pair of transparent substrates 11 and a step of applying an ultraviolet curable sealing material 13 on an opposing surface of one of the transparent substrates 11, Step of adhering the transparent substrates 11 and 12 to each other, a step of disposing a light shielding mask 16 capable of shielding light on the outer surface of one transparent substrate 12 leaving a portion corresponding to the sealing material, and an ultraviolet ray 20 from the outer surface of the light shielding mask 16. The step of irradiating and curing the sealing material 13 is included.

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 element used in office automation equipment such as personal computers and word processors, handy terminal equipment in the industrial field, portable information communication equipment and the like.

[0002]

2. Description of the Related Art Vacuum injection is generally well known as a conventional method for manufacturing a liquid crystal display device. As shown in FIG. 7, vacuum injection means to prepare an empty cell 40 in which two glass substrates 44 are bonded together with an adhesive, and a pool 45 in which the empty cell 40 and liquid crystal 42 are stored in a vacuum chamber 41. When the empty cell 40 is installed and a certain degree of vacuum is reached, one inlet 43 of the empty cell 40 is immersed in the pool 45, and the pressure in the vacuum tank 41 is returned to atmospheric pressure. It is sucked up by a phenomenon. Then, when the liquid crystal spreads over the entire surface of the empty cell 40, an adhesive is applied to the injection port 43 to seal it. Empty cell 4
A thermosetting resin or an ultraviolet curable resin is generally used as the sealing resin of No. 0. Although the liquid crystal 42 of the liquid crystal display element can be injected through the series of steps as described above, the injection work requires a long time. In particular, the larger the empty cell, the longer it takes to make the pressure in the vacuum chamber 41 equal to the pressure in the empty cell 40. Further, in order to increase the response speed of the liquid crystal display element in the future, the cell gap tends to be about 6 to 7 μm, which is the conventional value, to about 4 μm. The narrower the cell gap, the more constant the time required to make the pressure in the empty cell 40 constant or to pull up the liquid crystal by the capillary phenomenon. Therefore, at present, various methods have been proposed which can shorten the process.

For example, as a method of sealing a liquid crystal material in a liquid crystal display element in a short time, there is a dropping method shown in FIG. An alignment film has already been formed on the inner surfaces of the two glass substrates 50 and 51, and then a rubbing treatment is performed. On one of the glass substrates 50, a seal resin 54 for bonding is pattern-formed by screen printing or a dispenser. Considering the post-process, it is desirable to use a photo-curing resin instead of a thermosetting resin for the sealing resin 54. A gap of the liquid crystal display element can be formed by dropping an appropriate amount of liquid crystal 52 on the other glass substrate 51. Then, both glass substrates 50 and 51 are placed in a vacuum chamber 53, and when the inside of the chamber reaches an optimum vacuum degree, both glass substrates 50 and 51 are bonded. Then, in order to cure the seal resin 54 of the bonded glass substrates 50 and 51, the entire surface is irradiated with ultraviolet rays to crosslink and solidify the seal resin 54. Next, the glass substrates 50 and 51 are cut, leaving a region to be a liquid crystal display element.

The liquid crystal display device can be completed in a short time by the above steps, and continuous process steps can be built in-line without relying on a long time step such as vacuum injection or batch processing. In addition, even if the size of the liquid crystal display element is large or the cell gap is narrow, the time required for cell formation does not change at all.

[0005]

As described above, it is important to make a liquid crystal cell in a short time by using the ultraviolet curable seal resin 54 by the dropping method, but the seal resin 54 is cured by ultraviolet rays. At that time, the liquid crystal material in the liquid crystal display element may be adversely affected by ultraviolet rays.
Since a general liquid crystal material is weak against ultraviolet rays, the resistance value of the liquid crystal material may change or the components may be decomposed by strong ultraviolet rays. When such a liquid crystal display element is subjected to a reliability test, the current value and the optical characteristics change significantly, and it cannot be guaranteed as a liquid crystal display device.

In recent years, many liquid crystal materials have strong ultraviolet rays, but there is a strong demand from end users for a liquid crystal display element having a uniform and beautiful display quality. Therefore, stability with respect to the liquid crystal material in the liquid crystal display element is required, and adverse effects in the process must be prevented. From the above points, there is a demand for a method of suppressing the adverse effect of ultraviolet irradiation on the liquid crystal material and the alignment film when the sealing resin of the liquid crystal display element is cured.

The present invention solves the above-mentioned conventional problems, and provides a method of manufacturing a liquid crystal display device which can obtain a liquid crystal display device having excellent display quality while using an ultraviolet curable resin as a sealing material. The purpose is to

[0008]

According to a first aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, comprising a step of dropping a liquid crystal material on an opposing surface of one of a pair of transparent substrates, and an ultraviolet ray on the opposing surface of the one transparent substrate. A step of applying a curable sealing material, a step of bonding a pair of transparent substrates, a step of disposing a light shielding mask capable of shielding light on the outer surface of one transparent substrate leaving a portion corresponding to the sealing material, and a light shielding mask The step of irradiating ultraviolet rays from the outer surface to cure the sealing material.

According to the method of manufacturing a liquid crystal display element of claim 1, the ultraviolet light irradiated to cure the sealing material made of the ultraviolet curable resin is applied to the liquid crystal or the alignment film other than the sealing material. In order to prevent the occurrence of the above, the light can be shielded by the light shielding mask, and the sealing material can be smoothly cured without causing the alignment disorder and the threshold unevenness. The method of manufacturing a liquid crystal display element according to claim 2, wherein a step of dropping a liquid crystal material on one of the opposing surfaces of the pair of transparent substrates and a step of applying an ultraviolet curable sealing material to the opposing surface of the one transparent substrate. When,
A step of bonding a pair of transparent substrates, a step of disposing a light-shielding mask that can shield light on the outer surface of one transparent substrate leaving a portion corresponding to the sealing material, and a surface of the other transparent substrate that can shield the entire surface of the substrate It includes a step of disposing the entire surface light-shielding member, and a step of irradiating ultraviolet rays from the outer surface of the light-shielding mask to cure the sealing material.

According to the method of manufacturing a liquid crystal display element of claim 2, the ultraviolet rays radiated to cure the sealing material made of the ultraviolet curable resin are radiated to the liquid crystal and the alignment film other than the sealing material. In order to prevent the occurrence of the above, the light can be shielded by the light shielding mask, and the sealing material can be smoothly cured without causing the alignment disorder and the threshold unevenness. Further, it is possible to prevent the ultraviolet rays transmitted through the sealing material from rebounding and entering the liquid crystal display element by the entire surface light shielding member.

According to a third aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, which comprises a step of dropping a liquid crystal material on an opposing surface of one of a pair of transparent substrates and an ultraviolet curable sealing material on the opposing surface of the one transparent substrate. The step of applying, the step of adhering a pair of transparent substrates, the step of disposing a pair of light-shielding masks capable of shielding light on the outer surface of each transparent substrate, leaving a portion corresponding to each sealing material, and the outer surface of one light-shielding mask And irradiating ultraviolet rays to cure the sealing material.

According to the method of manufacturing a liquid crystal display element of claim 3, the ultraviolet rays irradiated to cure the sealing material made of the ultraviolet curable resin are irradiated to the liquid crystal or the alignment film other than the sealing material. In order to prevent the occurrence of the above, the light can be shielded by the light shielding mask, and the sealing material can be smoothly cured without causing the alignment disorder and the threshold unevenness. Further, it is possible to prevent the ultraviolet rays that have passed through the sealing material from rebounding and entering the liquid crystal display element by the light shielding mask on the side opposite to the ultraviolet rays.

A method for manufacturing a liquid crystal display element according to a fourth aspect is characterized in that, in the first, second or third aspect, the side surface of the liquid crystal display element is irradiated with ultraviolet rays while being shielded by a side light shielding member. is there. According to the manufacturing method of the liquid crystal display element of the fourth aspect, it is possible to prevent the ultraviolet rays from wrapping around and entering from the side surface of the liquid crystal display element by the side light shielding member.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment A method of manufacturing a liquid crystal display element according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
FIG. 1 is a configuration diagram of a step of curing the sealing material 13 in the manufacturing process of the liquid crystal display element 10. In the figure, reference numerals 11 and 12 denote a pair of glass substrates each having an alignment film formed on its inner surface and subjected to a rubbing treatment, and a sealing material 13 made of an ultraviolet curable resin is applied to the opposing surfaces of the glass substrate 11 (or 12). Then, the liquid crystal material is dropped onto the opposite surface of the other glass substrate 12 and bonded. Further, 14 is a lamp for irradiating the liquid crystal display element 10 with ultraviolet rays 20,
Reference numeral 15 denotes a reflector, which irradiates the entire surface of the liquid crystal display element 10 with ultraviolet rays 20 from the glass substrate 12 side.

A light-shielding mask 16 is provided between the lamp 14 and the liquid crystal display element 10 so as to be in contact with the liquid crystal display element 10. The light-shielding mask 16 is formed by forming a light-shielding film 18 on a light-transmitting substrate 17, and the pattern of the light-shielding film 18 is determined according to the pattern of the sealing material 13. That is, when the pattern of the sealing material 13 is as shown in FIG. 2, the pattern of the light shielding mask 16 is such that the light shielding film 18 is formed leaving the portion corresponding to the sealing material 13 as shown in FIG. The transparent substrate 17 is made of glass, and when the plate thickness is 4 mm or more, it does not warp due to the influence of heat and the light shielding film 18 is patterned with black ink.

The ultraviolet rays 20 emitted from the lamp 14 are
The light is transmitted through the light-transmitting portion 19 of the light-shielding mask 16 where the light-shielding film 18 is not formed, and only the sealing material 13 is irradiated, and the sealing material 13 is cured. The sealing material 13 and the light shielding mask 16
Regarding the pattern matching, it is required that the liquid crystal and the alignment film are locally irradiated with the ultraviolet rays 20 due to the leakage of the ultraviolet rays 20, and the alignment is not disturbed and threshold unevenness is not generated. Further, if it takes too much time from the bonding of the glass substrates 11 and 12 to the irradiation of the sealing material 13 with the ultraviolet rays 20, the sealing material 13 may melt into the liquid crystal due to uncured, and this step is short. Need to be processed in time.

According to the method of manufacturing a liquid crystal display element having such a structure, the ultraviolet rays 20 irradiated to cure the sealing material 13 do not irradiate the liquid crystal or the alignment film other than the sealing material 13. As described above, the light shielding mask 16 shields the light, and the sealing material 13 can be smoothly cured without causing the alignment disorder and the threshold unevenness. Therefore, while using the ultraviolet curable resin for the sealing material 13,
The liquid crystal display element 10 having excellent display quality can be obtained.

Further, since only the light-shielding mask 16 is installed, the process can be smoothly introduced, and the equipment cost is low. Second Embodiment A method of manufacturing a liquid crystal display element according to the second embodiment of the present invention will be described with reference to FIG. The first
The same parts as those of the embodiment are given the same reference numerals and the description thereof will be omitted.

That is, the ultraviolet ray 20 transmitted through the light transmitting portion 19 of the light shielding mask 16 and the sealing material 13 hits a surrounding object and is reflected, whereby the liquid crystal display element 10 is reflected.
However, the present embodiment relates to a method of manufacturing a liquid crystal display element capable of preventing the liquid crystal, the alignment film, or the like of the liquid crystal display element 10 from being irradiated. Is.

When the liquid crystal display element 10 is a color panel,
By using a color filter for the glass substrate 11 of the liquid crystal display element 10 on the anti-ultraviolet irradiation side, the rebound of the ultraviolet rays 20 that have passed through the sealing material 13 can be suppressed.
However, in the case of a black-and-white panel, the rebounded ultraviolet rays 20 are applied to the entire surface of the liquid crystal display element 10, which adversely affects the liquid crystal material and the alignment state.

Therefore, the entire outer surface of the glass substrate 11 on the side opposite to the irradiation of the ultraviolet rays 20 is covered with the entire light shielding member 25. The entire surface light-shielding member 25 has the same size as that of the liquid crystal display element 10 and is made of a light-shielding material. It is particularly preferable that the surface light-shielding member 25 is subjected to a surface treatment that is black and difficult to reflect. Normally, black ink may be used, but the film thickness and other factors are controlled so that the light-shielding rate becomes extremely good.

Also in the method of manufacturing the liquid crystal display element having such a structure, the same effect as that of the first embodiment can be obtained. Furthermore, the sealing material 1 is provided by the entire surface light-shielding member 25.
The ultraviolet ray 20 that has passed through 3 bounces back to the liquid crystal display element 1
It is possible to prevent irradiation of the liquid crystal of 0, the alignment film, etc., and to obtain the liquid crystal display element 10 having excellent display quality.
In addition, the liquid crystal display element 1 is provided on the entire surface light-shielding member 25 including a stage such as a surface plate that is black and has a surface treatment that is difficult to reflect.
0 is installed, and ultraviolet rays 2 from above through the light-shielding mask 16.
The sealing material 13 can be cured by irradiating 0, and as a result, the holding structure of the liquid crystal display element 10 becomes simple.

Third Embodiment A method of manufacturing a liquid crystal display element according to a third embodiment of the present invention will be described with reference to FIG. The first
The same parts as those of the embodiment are given the same reference numerals and the description thereof will be omitted. In this embodiment, a light-shielding mask 30 similar to the light-shielding mask 16 matched with the pattern of the sealing material 13 is also provided on the anti-ultraviolet irradiation side of the liquid crystal display element 10, and the two light-shielding masks 16 and 30 are used for the liquid crystal display element. 10 is sandwiched between them. The light-shielding mask 30 is formed by forming a light-shielding film 31 of black ink or the like on the surface of a light-transmissive glass substrate 33 except for the portion corresponding to the sealing material 13, and the ultraviolet rays 20 transmitted through the sealing material 13 are: The light is transmitted through the light transmitting portion 32 of the light shielding mask 30 and is not reflected by the surface of the light shielding mask 30.

Also in the method of manufacturing the liquid crystal display element having such a structure, the same effect as that of the first embodiment can be obtained. Further, the sealing material 13 is provided by the light-shielding mask 30.
The ultraviolet rays 20 that have passed through the surface of the liquid crystal bounce back to the liquid crystal display element 10.
It is possible to prevent the liquid crystal, the alignment film, and the like from being irradiated, and also to prevent the ultraviolet rays 20 from being reflected on the surface of the light-shielding mask 30 and entering the liquid crystal display element 10, thereby providing a liquid crystal display having excellent display quality. The element 10 can be obtained.

Fourth Embodiment A method of manufacturing a liquid crystal display device according to a fourth embodiment of the present invention will be described with reference to FIG. The first
The same parts as those of the embodiment are given the same reference numerals and the description thereof will be omitted. In this embodiment, ultraviolet rays 2 from the side surface of the liquid crystal display element 10 (the edge portions of the glass substrates 11 and 12) are used.
This is to prevent 0 from wrapping around. That is, the entire light shielding member 25 is provided on the outer surface of the glass substrate 11, and the entire side surface of the liquid crystal display element 10 is covered with the side light shielding member 35. The side light-shielding member 35 is formed of a vacuum groove for suppressing warpage of the liquid crystal display element 10 on the surface plate, a cloth having a dense cloth, or the like.

Also in the method of manufacturing the liquid crystal display element having such a structure, the same effect as that of the second embodiment can be obtained. Further, there is almost no ultraviolet ray 20 that wraps around from the side surface of the liquid crystal display element 10, does not affect the liquid crystal material and the alignment film of the liquid crystal display element 10, has excellent reliability, and is uniform in display quality and has no unevenness. Is obtained.

In the first embodiment in which only the light-shielding mask 16 is provided, the side-face light-shielding member 35 is provided, and the ultraviolet rays 2
0 may be prevented, or the side surface light shielding member 35 may be provided in the third embodiment in which the light shielding masks 16 and 30 are provided on both surfaces of the liquid crystal display element 10 to prevent the ultraviolet rays 20 from sneaking in. Good.

[0028]

According to the method of manufacturing a liquid crystal display element of claim 1, the ultraviolet rays irradiated to cure the sealing material made of the ultraviolet curable resin are irradiated to the liquid crystal and the alignment film other than the sealing material. As a result, the light can be shielded by a light-shielding mask, and the curing of the sealing material can be smoothly performed without causing the alignment disorder and the threshold unevenness.

According to the method of manufacturing a liquid crystal display element of claim 2, the ultraviolet light irradiated to cure the sealing material made of the ultraviolet curable resin is applied to the liquid crystal or the alignment film other than the sealing material. In order to prevent the occurrence of the above, the light can be shielded by the light shielding mask, and the sealing material can be smoothly cured without causing the alignment disorder and the threshold unevenness. Further, it is possible to prevent the ultraviolet rays transmitted through the sealing material from rebounding and entering the liquid crystal display element by the entire surface light shielding member.

According to the method of manufacturing a liquid crystal display element of claim 3, the ultraviolet light irradiated to cure the sealing material made of the ultraviolet curable resin is applied to the liquid crystal or the alignment film other than the sealing material. In order to prevent the occurrence of the above, the light can be shielded by the light shielding mask, and the sealing material can be smoothly cured without causing the alignment disorder and the threshold unevenness. Further, it is possible to prevent the ultraviolet rays that have passed through the sealing material from rebounding and entering the liquid crystal display element by the light shielding mask on the side opposite to the ultraviolet rays.

According to the manufacturing method of the liquid crystal display element of the fourth aspect, it is possible to prevent the ultraviolet rays from wrapping around and entering from the side surface of the liquid crystal display element by the side light shielding member. As a result, a liquid crystal display element having excellent reliability and display quality can be manufactured. Further, since only a light-shielding mask that shields ultraviolet rays, the entire surface light-shielding member, and the side-face light-shielding member are installed, the process can be smoothly introduced and the equipment cost is low. Moreover, since it can be introduced in a form suitable for mass production by a dropping method using an ultraviolet curing type sealing material, in-line operation and tact time are short, and efficient work is possible. By establishing this process, the effect of the dropping method can be further utilized, and even in a large-sized liquid crystal panel or a liquid crystal display element with a narrow cell gap, the work time is the same, and the required time is about 1/10 that of the vacuum injection method. Becomes

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of a liquid crystal display element according to a first embodiment of the present invention.

FIG. 2 is a pattern diagram of a sealing material of the liquid crystal display element according to the first embodiment of the present invention.

FIG. 3 is a pattern diagram of a light-shielding mask according to the first embodiment of the present invention.

FIG. 4 is a manufacturing process diagram of a liquid crystal display element according to a second embodiment of the present invention.

FIG. 5 is a manufacturing process diagram of a liquid crystal display element according to a third embodiment of the present invention.

FIG. 6 is a manufacturing process drawing of a liquid crystal display element according to a fourth embodiment of the present invention.

FIG. 7 is an explanatory diagram of a vacuum injection method of a liquid crystal material.

FIG. 8 is an explanatory diagram of a dropping method of a liquid crystal material.

[Explanation of symbols]

 10 liquid crystal display element 11, 12 glass substrate 13 sealing material 16, 30 light-shielding mask 25 entire surface light-shielding member 35 side light-shielding member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Yamada 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A step of dropping a liquid crystal material on one of the opposing surfaces of a pair of transparent substrates, a step of applying an ultraviolet-curable sealing material to the opposing surface of the one transparent substrate, and the pair of transparent substrates. And a step of arranging a light-shielding mask capable of shielding light on the outer surface of one of the transparent substrates, leaving a portion corresponding to the seal material, and irradiating ultraviolet rays from the outer surface of the light-shielding mask to cure the seal material. A method of manufacturing a liquid crystal display element, the method including: 2. A step of dropping a liquid crystal material on one of the opposing surfaces of the pair of transparent substrates, a step of applying an ultraviolet-curing sealing material to the opposing surface of the one transparent substrate, and the pair of transparent substrates. And a step of disposing a light-shielding mask capable of shielding light on the outer surface of one transparent substrate while leaving a portion corresponding to the sealing material, and a total light-shielding member capable of shielding the entire surface of the other transparent substrate. And a step of irradiating ultraviolet rays from the outer surface of the light-shielding mask to cure the sealing material. 3. A step of dropping a liquid crystal material on one of the opposing surfaces of the pair of transparent substrates, a step of applying an ultraviolet-curable sealing material to the opposing surface of the one transparent substrate, and the pair of transparent substrates. And a step of arranging a pair of light-shielding masks capable of shielding light on the outer surface of each transparent substrate leaving a portion corresponding to the sealing material, respectively, and irradiating ultraviolet rays from the outer surface of one of the light-shielding masks And a step of curing the material. 4. The method for producing a liquid crystal display element according to claim 1, wherein the side surface of the liquid crystal display element is irradiated with ultraviolet rays while being shielded by a side light shielding member.