JP3104703B1 - Manufacturing method of liquid crystal element - Google Patents

Abstract

An object of the present invention is to secure long-term reliability in a liquid crystal element. SOLUTION: A low-viscosity ultraviolet curable resin is used for sealing an injection port of a liquid crystal cell so as to prevent bubbles from being present in the resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a liquid crystal device.

[0002]

2. Description of the Related Art In a conventional method of manufacturing a liquid crystal element, as shown in FIG. 2, a sealing resin is printed between two glass substrates 201 to form an empty cell having an inlet 203. Then, the liquid crystal 204 is vacuum-injected from the injection port 203, and when the liquid crystal 204 is completely injected, an ultraviolet curing resin is applied to the injection port in the air, the injection port is sealed, and ultraviolet light is irradiated to cure.

[0003]

However, in such a method, air bubbles often very often remain in the gap between the two glass substrates 201 of the injection port 203 when the ultraviolet resin is applied. Also, when such bubbles remain, as shown in FIG. 3, when the ultraviolet rays 301 are irradiated, the bubbles 303 remaining in the ultraviolet curing resin 302 refract the ultraviolet rays 301 and are present behind the bubbles 303 when viewed from the ultraviolet irradiation direction. The ultraviolet curable resin 302 becomes insufficiently irradiated with ultraviolet light. And the UV resin in the insufficient irradiation area
302 was uncured and the uncured resin diffused into the liquid crystal, resulting in reduced long-term reliability of the liquid crystal element.

However, an object of the present invention is to solve the above-mentioned problems of the prior art, that is, to ensure long-term reliability of a liquid crystal element. In addition, since the concentration of impurities in the liquid crystal is reduced, not only long-term reliability but also initial characteristics are improved.

[0005]

[0006]

[0007]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
The method of manufacturing the first liquid crystal element of the present invention, between the two substrates a liquid crystal element in which sandwich the liquid crystal, when the coating process of the ultraviolet curing resin into the injection port, or after said step There
Moreover, the ultraviolet curing resin is irradiated with ultraviolet rays to be cured.
Prior to the step of subjecting the ultraviolet curable resin to vibration.

[0008] The method of producing the second liquid crystal element of the present invention is a method of manufacturing a liquid crystal device characterized by using ultrasonic as a vibration given to the ultraviolet curing resin.

A third method of manufacturing a liquid crystal element according to the present invention is a method of manufacturing a liquid crystal element, wherein megasonic is used as vibration applied to the ultraviolet curable resin.

[0010]

[0011]

A fourth method of manufacturing a liquid crystal element according to the present invention is directed to a liquid crystal element having a liquid crystal sandwiched between two substrates, in a step of applying an ultraviolet curable resin to an injection port or after the step.
And irradiating the ultraviolet-curable resin with ultraviolet light.
A method for manufacturing a liquid crystal element, characterized in that at least an ultraviolet curable resin portion is accelerated before a curing step .

A fifth method of manufacturing a liquid crystal element according to the present invention is directed to a liquid crystal element in which liquid crystal is sandwiched between two substrates, at the time of applying an ultraviolet curable resin to an injection port or after the above step.
And irradiating the ultraviolet-curable resin with ultraviolet light.
Before the step of curing, at least one step of wiping the ultraviolet curable resin and a step of applying the ultraviolet curable resin again is performed.
This is a method for manufacturing a liquid crystal element, characterized by repeating at least twice.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for manufacturing a liquid crystal device according to the present invention will be described. An object of the method for manufacturing a liquid crystal element of the present invention is to prevent air bubbles from entering an ultraviolet curable resin portion sealing an injection port. The reason for this is that, as shown in the conventional example, the presence of air bubbles causes an uncured portion of the ultraviolet curable resin to be generated, which adversely affects the reliability.

As a specific method for leaving no bubbles, first, it is necessary that the viscosity of the ultraviolet curable resin for sealing is low. If the viscosity is low, the possibility of trapping bubbles when applying the resin to the injection port is reduced. Especially 20
A viscosity of Pa · s or less is better because almost no bubbles are trapped.

Second, when applying the ultraviolet curable resin to the injection port, the substrate side is warmed, or after application, heating is performed by heating only the resin or the entire substrate to substantially reduce the viscosity of the resin. It is effective to lower it. Further, if the temperature of the resin becomes less than 20 Pa · s by this heating, almost no bubbles are trapped, so that it is better.

Third, the UV curable resin may be preliminarily warmed to an appropriate temperature and applied with a reduced viscosity. If the heating temperature is too high, the resin will start to cure, so 80 ° C
The following is good. The viscosity of the resin when heated is desirably 20 Pa · s or less.

Fourth, it is preferable to apply an ultraviolet curable resin by a conventional method and, after holding the air bubbles, apply vibration to the entire substrate or the resin portion to remove the air bubbles. As a method of applying vibration at this time, it is more efficient and more preferable to use ultrasonic waves or megasonics.

Fifth, after applying an ultraviolet curable resin by a conventional method and holding the air bubbles, the air bubbles may be removed by bringing the air bubbles into contact with an object such as a rigid body, a fiber, or a brush.

Sixth, after applying an ultraviolet curable resin by a conventional method and holding air bubbles, the entire substrate or the resin portion is evacuated by a vacuum pump or the like, and is exposed to an environment lower than atmospheric pressure. Then, the diameter of the bubble increases, and eventually the bubble bursts and disappears.

Seventh, an ultraviolet curable resin is applied by a conventional method, and after holding air bubbles, acceleration is applied to the entire substrate or the resin portion to generate gravity. As this method, for example, there is a method of rotating with a device such as a centrifugal separator, but this may not be the method. In this way, the bubbles move in the direction opposite to the acceleration direction and disappear.

Eighth, an ultraviolet curable resin is applied by a conventional method, and after holding air bubbles, the resin is gently wiped once with a cloth or the like. Then, a thin resin remains on the glass surface near the injection port, and the resin is embedded in the gap between the two glass substrates. Then, when an ultraviolet curable resin is further applied, the wettability of the resin is extremely improved, and no bubbles remain. This step may be performed repeatedly.

As shown in FIG. 1, an ultraviolet curing resin 102 is applied to an injection port 101 by various methods as described above, and then an ultraviolet ray 103 is applied.
Irradiates the ultraviolet curable resin 102 with no air bubbles, so the irradiated ultraviolet light 103 is irradiated evenly without significant refraction in the ultraviolet curable resin 102 (however, there is attenuation). Is completely cured.

The liquid crystal device thus manufactured exhibits a voltage holding ratio of 99% as an initial characteristic, is stable for 10,000 hours in a high temperature test (70 ° C.), and changes to a characteristic of 10,000 hours in a continuous driving test. It was confirmed that there was no.

The liquid crystal element referred to in the present invention is a liquid crystal display element,
It refers to all elements in which liquid crystal is sandwiched between substrates, such as optical switching elements.

[0026]

According to the present invention, since no bubbles are generated in the resin portion sealing the injection port, the uncured portion of the ultraviolet curable resin is eliminated. Therefore, the diffusion of the uncured resin into the liquid crystal is eliminated, so that the initial characteristics and long-term reliability of the liquid crystal element are greatly improved.

[Brief description of the drawings]

FIG. 1 is a conceptual cross-sectional view showing curing in a method for manufacturing a liquid crystal element of the present invention.

FIG. 2 is a cross-sectional view of a prior art liquid crystal cell.

FIG. 3 is a cross-sectional view of a liquid crystal cell showing a problem of the related art.

[Explanation of symbols]

 101 Inlet 102 UV curable resin 103 UV 104 Seal resin 105 Liquid crystal 201 Glass substrate 202 Seal resin 203 Injection 204 Liquid crystal 205 UV curable resin 206 Bubbles 301 UV 302 UV curable resin 303 Bubbles 304 Seal resin 305 Glass substrate

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Yukio Tanaka 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-10-3085 (JP, A) JP-A-9-101527 (JP, A) JP-A-7-84230 (JP, A) JP-A-7-306415 (JP, A) JP-A-2-277022 (JP, A) JP-A-11-295745 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1341

Claims (5)

(57) [Claims] 1. A method of manufacturing a liquid crystal element having a liquid crystal sandwiched between two substrates, the method comprising: applying a UV curable resin to an injection port or after the step ;
Before the step of irradiating the ultraviolet curing resin with ultraviolet rays and curing it
A method for producing a liquid crystal element , wherein vibration is applied to the ultraviolet curable resin. 2. The method for manufacturing a liquid crystal element according to claim 1, wherein ultrasonic waves are used as vibrations applied to the ultraviolet curable resin. 3. The method for manufacturing a liquid crystal element according to claim 1, wherein megasonic is used as the vibration applied to the ultraviolet curable resin. 4. A method for manufacturing a liquid crystal element having a liquid crystal sandwiched between two substrates, the method comprising the steps of: applying a UV curable resin to an injection port or after the step ;
Before the step of irradiating the ultraviolet curing resin with ultraviolet rays and curing it
And applying an acceleration to at least the ultraviolet curable resin portion. 5. A method of manufacturing a liquid crystal device was sandwiched a liquid crystal between two substrates, a later coating step during or said step of UV curing resin into injection port Moreover, the
Before the step of irradiating the ultraviolet curing resin with ultraviolet rays and curing it
And a step of repeating the step of wiping off the ultraviolet curable resin and the step of applying the ultraviolet curable resin again at least once or more.