JPH06148639A - Liquid crystal panel - Google Patents

Abstract

PURPOSE:To improve display grade and manufacturing yield by bringing substance representing a liquid crystal state in a certain temperature range into contact with a heated substrate in isotropic solution state, and orienting and attracting the substance on a substrate main plane in a specific process as exposing in a magnetic field. CONSTITUTION:Nematic liquid crystal 4 with clearing point of around 80 deg.C is generated as isotropic solution by heating to around 100 deg.C and simultaneously, a substrate 6 consisting of an undercoated glass plate 2 and ITO 3 to which fine working is applied is also heated to around 100 deg.C on the same hot plate 1. The substrate 6 is soaked in the liquid crystal 4, and liquid crystal temperature is decreased to 75 deg.C so as to change the liquid crystal 4 from an isotropic solution state to a liquid crystal state as impressing a magnetostatic field in a desired direction to the substrate 6 by the pole piece 9 of an electromagnet while the liquid crystal is being maintained in the isotropic state. The substrate 10 drawn out from the liquid crystal 4 is soaked in ethanol 11, and most of the liquid crystal attached on the substrate 10 is removed. A pair of substrates are adhered so as to make the directions of impressed magnetic fields coincide with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal panel.

[0002]

In the production of liquid crystal display devices, fibers such as rayon are used to rub the resin film at high speed (this operation is also referred to as rubbing) to stretch organic long-chain molecules constituting the resin film. And liquid crystal molecules are brought into contact with each other to orient the liquid crystal molecules.

This technical content is detailed in "Liquid Crystal / Applied Edition", Koji Okano, Shunsuke Kobayashi, co-edition, published by Baifukan.

[0004]

In manufacturing a liquid crystal display device, a key step is manufacturing a liquid crystal panel. This invention, even in the process of manufacturing a liquid crystal panel,
It relates to the process of achieving important liquid crystal molecule alignment.

The conventional rubbing technique has the following problems. In the first place, when manufacturing a liquid crystal panel, we dislike dust, and therefore, it is done in a dust-free room. However, the fibers used in the rubbing process are highly likely to generate dust, and it is unsuitable to bring this into a dust-free chamber.

More specifically, high-speed friction causes a large amount of dust and dirt in practice. Dust and dust are pieces of fibers, shavings of resin film, abrasion scraps of machine parts due to high-speed movement of the machine, etc., which naturally lower the yield of products.

In such a mechanical rubbing operation,
It is often difficult to stretch organic long-chain molecules that form a uniform resin film, and as a result, it is often difficult to achieve uniform alignment of liquid crystal molecules and thus uniform display.

Further, in the recent liquid crystal display device, the angle (so-called pretilt angle) formed by the substrate and the longitudinal direction of the liquid crystal molecules at the interface of the liquid crystal-substrate is about 5 ° or more. The in-plane uniformity of this corner is important. This pretilt angle slightly changes due to local variations in the rubbing strength, and this is reflected in the display. Also,
It is necessary to change the structure of molecules forming the resin film depending on the desired pretilt range. Further, it has not been industrially successful to secure the uniformity and reproducibility of pretilt of about 10 ° or more.

Further, since the rubbing operation is high-speed friction, the adhesive force of the resin film to the substrate is important. In order to secure this, it is general to introduce a silane coupler or the like into the resin film. However, this silane coupler tends to adsorb liquid crystal molecules and impurity molecules in the liquid crystal, thus making the display dirty.

[0010]

In order to solve the above-mentioned problems, the present invention heats a substrate and a substance exhibiting a liquid crystal state within a certain temperature range, and makes the principal surface of the substrate into an isotropic liquid state. This substance is brought into contact and exposed to a magnetic field having magnetic lines of force in a desired direction with respect to this substrate, and one or more of the following steps, namely, the substance is cooled from an isotropic liquid state to a liquid crystal state. Process and, if desired, the substance is in the liquid crystal state and is kept at as high a temperature as possible, and then the substrate is briefly washed with an aqueous or alcoholic liquid to remove most of the substance. After removing from the main surface, a pair of such substrates are made to face each other with their main surfaces facing each other and are bonded with a predetermined gap, and in this gap,
A liquid crystal panel obtained by filling a predetermined liquid crystal composition is revealed.

At this time, the substance is intended to be a molecule having a functional group such as an amino group or an alkoxy group as an impurity,
Even when included, the effect of the present invention is exhibited.

At this time, the main surface of the substrate is made of an insulating oxide such as silicon dioxide or an ITO layer, or the main surface of the substrate is made of an insulating oxide such as silicon dioxide. Alternatively, it is preferable that the ITO layer and the molecular layer have a reactive group such as an alkoxysilane group and the other end have a structure similar to the nucleus of the low-molecular liquid crystal. A molecule having a functional group such as an alkoxysilane group at the terminal and a structure similar to the nucleus of a low-molecular liquid crystal at the other terminal is generally commercially available as a vertical aligning agent.

The main surface of the substrate is made of an organic resin layer such as a polyimide resin layer, a polyparabanic acid resin layer or a coupler layer, or the main surface of the substrate is made of an organic resin layer such as a polyimide resin layer, a polyparabanic acid resin layer or a coupler layer. The resin layer and a molecular layer having a functional group such as an alkoxysilane group at the end of the molecule and the other end having a structure similar to the nucleus of a low-molecular liquid crystal are laminated, or the main surface of the substrate is made of polyimide. The resin and the terminal of the molecule have a functional group such as an alkoxysilane group, the other terminal is a mixture layer with a molecule having a structure similar to the nucleus of a low-molecular liquid crystal or a mixture layer of the polyparabanic acid resin and the molecule, It is preferably composed of a mixture layer of an organic resin and the molecule, such as a mixture layer of a coupler and the molecule.

[0014]

First, the assumed hypothetical principle of the present invention will be described.

A substrate and a substance exhibiting a liquid crystal state in a certain temperature range are heated, and this substance in an isotropic liquid state is brought into contact with the main surface of the substrate. At this time, the components of this substance or decomposition products or impurities thereof, which are adsorbed or fixed on the main surface of the substrate, will be very small.

Next, while subjecting this substrate to a magnetic field having magnetic lines of force in a desired direction, the following singular or plural processes, that is, a process of lowering the temperature of this substance from an isotropic liquid state to a liquid crystal state, Further, if desired, a process of keeping the substance in a liquid crystal state and at a temperature as high as possible is performed. At this time, when the substance changes from an isotropic liquid state to a liquid crystal state, the magnetic field causes the molecules of the substance to be oriented due to diamagnetism. Furthermore, the component of this substance or its decomposition product or impurity (there is one having a functional group) is adsorbed or fixed to the main surface of the substrate. This adsorbed or fixed substance, in turn, turns a general liquid crystal molecule into
It should be oriented as described above.
The impurities having such a functional group may be added intentionally.

Of course, the direction of the lines of magnetic force has a major meaning in providing the uniaxiality of the liquid crystal. That is, in the case of a nematic liquid crystal, the direction of the director of liquid crystal molecules near the interface is mainly determined, and in the case of a ferroelectric liquid crystal element, the layer direction of liquid crystal alignment is mainly determined.

Next, the substrate is washed with an aqueous liquid or an alcohol liquid for a short time to remove most of the substance from the main surface. At this time, most of the adsorbed or fixed matter on the main surface of the substrate must be free from the influence. When using an aqueous liquid, pay attention to the choice of detergent, and when using an alcohol liquid, it is necessary to compromise the cleaning ability such as ethanol.

With such a pair of substrates having their principal surfaces opposed to each other,
A liquid crystal panel is obtained, which is characterized in that it is pasted with a predetermined gap and the predetermined liquid crystal composition is filled in this gap. At this time, the liquid crystal molecules are aligned in a desired direction from the above-mentioned matter. From the essence of this orientation method, compared to the conventional method,
It is natural that the uniformity can be improved.

Molecules having a reactive group such as an alkoxysilane group at the end of the molecule and a structure similar to the nucleus of the low-molecular liquid crystal at the other end (that is, a commercially available vertical alignment agent) It is important to allow the liquid crystal to be present on the main surface of the substrate in order to uniformly obtain a high pretilt of liquid crystal molecules.

[0021]

EXAMPLES Examples of the present invention will be described below.

(Embodiment 1) The construction will be described with reference to FIG. In (Fig. 1), 1 is about 100 ℃ on the surface
A hot plate, 2 is an undercoated glass plate, 3 is a finely processed ITO, in this case IT
The surface with O is the main surface, and 2 and 3 are collectively referred to as the substrate. 4 is a nematic liquid crystal having a clearing point of about 80 ° C., 5 is a glass container, 6 is the substrate, 7 is a nematic liquid crystal having a clearing point of about 80 ° C., 8 is the same glass container as 5 , 9 are pole pieces of electromagnets. 10 is the same substrate as 6, 6, 11 is ethanol, and 12 is a container.

In FIG. 1 (a), the material herein, ie, a nematic liquid crystal having a clearing point of about 80 ° C. in this example, in a sufficient amount, is heated to about 100 ° C. At this time, the nematic liquid crystal was a transparent isotropic liquid because of the high temperature. At the same time, the substrate having ITO was also heated to about 100 ° C. on the same hot plate.

Immediately immerse the substrate heated to about 100 ° C. in the above-mentioned nematic liquid crystal heated to about 100 ° C. in the glass container 8 and, while the liquid crystal is still an isotropic liquid, As shown in FIG. 1B, the temperature of the nematic liquid crystal 7 in the glass container is rapidly applied to the substrate 6 in the glass container 8 while applying a static magnetic field so that magnetic lines of force are formed in a desired direction. Was lowered to about 75 ° C. At this time, the size of the glass container 5 (same as 8) was adjusted so that the thickness of the nematic liquid crystal layer through which the magnetic force lines were transmitted was about 100 μm, and the magnetic field strength was about 10 Tesla. Although not shown in (FIG. 1) (b), a small non-magnetic heater is used to fix the glass container 8 containing the substrate and the nematic liquid crystal as described above, including the relative orientations of the substrate and the magnetic lines of force. Hold at about 75 ° C for 10 minutes.

Drawing the substrate out of the nematic liquid crystal,
(FIG. 1) As in (C), dip in ethanol to remove most of the liquid crystal attached to the substrate.

Next, using a known technique, such a pair of substrates are made to face each other at their principal surfaces, the magnetic field directions applied to the respective substrates are made to coincide with each other, and they are bonded with a gap of about 2 μm, and the gap is strongly strengthened. A dielectric liquid crystal composition was filled to obtain a liquid crystal panel. When a voltage was applied to the ITO using a polarizing plate and the display characteristics of the liquid crystal panel were evaluated, a good display without any zigzag could be obtained.

Further, with the aid of a known technique, about 7 μm is taken into consideration so that the arrangement of liquid crystal molecules may be twisted at a desired angle.
The liquid crystal composition for P-type STN was filled in this space and the liquid crystal panel was obtained. in this case,
The twist angle of the liquid crystal array was set to 220 °. When a voltage was applied to the ITO using a polarizing plate and the display characteristics of the liquid crystal panel were evaluated, it was possible to obtain a very uniform and good display.

The reliability of the alignment of the liquid crystals of the above two types of liquid crystal panels was excellent. (Embodiment 2) The sectional view of the structure shown in FIG. 2 relates to the substrate used in this embodiment. In the figure, 13 is an undercoated glass plate, 14 is an ITO electrode, and 15 is 2
This is a top coat made of silicon oxide.

The same treatment as in Example 1 was carried out to obtain a liquid crystal panel. In terms of display, uniformity has been improved even more than before.

(Embodiment 3) The sectional view of the structure shown in FIG. 3 relates to the substrate used in this embodiment. In the figure, 16 is an undercoated glass plate, and 17 is IT.
O electrode, 18 is a top coat made of silicon dioxide, 19
Manufactured by Merck & Co., a vertical alignment agent, ZLI-3334 0.
It is an ultrathin film obtained by applying a 2 wt% solution to a spinner. ZL
The molecule of I-3334 has an alkoxy-silane group at the molecular end, and the molecular skeleton has a structure similar to liquid crystal.

The same process as in Example 1 was carried out to obtain a liquid crystal panel. In terms of display, uniformity has been improved even more than before.

As a result of pretilt measurement at the substrate interface using a tilted nematic liquid crystal, a high pretilt of about 15 ° was reproducibly obtained.

Example 4 The same process as in Example 1 was carried out to obtain a liquid crystal panel. However, for liquid crystal 4 to 7,
0.001% by weight of vertical aligning agent 3334 was mixed. As a result, the display is much more uniform than before.

As a result of pretilt measurement at the interface of the substrate using the nematic liquid crystal which is tilted and aligned, a high pretilt of about 10 ° was obtained with good reproducibility.

(Embodiment 5) The sectional view of the structure shown in FIG. 4 relates to the substrate used in this embodiment. In the figure, 20 is an undercoated glass plate, and 21 is IT.
O electrode, 22 is a top coat made of silicon dioxide, 23
Is an ultrathin film of Nippon Synthetic Rubber Co., Ltd., polyimide, JIB-1, or Tonen Kagaku Co., Ltd., polyparabanic acid resin, sollac, or Toshiba Silicone, coupler, TSL8173, or TSL8.
172 is an ultra-thin film, or Shin-Etsu Silicone Coupler, an ultra-thin film of KBM303 or X-641.

The same treatment as in Example 1 was carried out to obtain a liquid crystal panel. In terms of display, uniformity has been improved even more than before.

(Embodiment 6) The sectional view of the structure shown in FIG. 5 relates to the substrate used in this embodiment. In the figure, 24 is an undercoated glass plate, and 25 is IT.
O electrode, 26 is a top coat made of silicon dioxide, 27
Is an ultrathin film of Nippon Synthetic Rubber Co., Ltd., polyimide, JIB-1, or Tonen Kagaku Co., Ltd., polyparabanic acid resin, sollac, or Toshiba Silicone, coupler, TSL8173, or TSL8.
172, or an ultra thin film of Shin-Etsu Silicone, a coupler, an ultra thin film of KBM303 or X-641, 28 is an ultra thin film of a Merck company, a vertical alignment agent, and a spinner coating of a 0.2 wt% solution of ZLI-3334. .

The same processing as in Example 1 was carried out to obtain a liquid crystal panel. In terms of display, uniformity has been improved even more than before.

The pretilt angle was about 12 ° and the reproducibility was good. (Embodiment 7) The sectional view of the structure shown in FIG. 6 relates to the substrate used in this embodiment. In the figure, 29 is an undercoated glass plate, 30 is an ITO electrode, and 31 is 2
The top coat made of silicon oxide, 32 is a polyimide, JIB-, manufactured by Japan Synthetic Rubber Co., Ltd. by spinner coating.
Vertical alignment agent, ZLI-3334 0.001 wt% mixed liquid, or Tonen Kagaku Co., Ltd., polyparabanic acid resin, Sollac, vertical alignment agent, ZLI-33
It is an extremely thin film of a mixed liquid containing 0.001% by weight of 34.

The same processing as in Example 1 was carried out to obtain a liquid crystal panel. In terms of display, uniformity has been improved even more than before.

The pretilt angle was about 13 ° and the reproducibility was good.

[0042]

As described above, the present invention provides an effective method for improving the display quality of a display device and improving the manufacturing yield, and greatly contributes to the industry.

[Brief description of drawings]

FIG. 1 is a structural cross-sectional view for explaining an embodiment of the present invention.

FIG. 2 is a sectional view showing the structure of a substrate according to an embodiment of the present invention.

FIG. 3 is a sectional view showing the structure of a substrate according to an embodiment of the present invention.

FIG. 4 is a sectional view showing the structure of a substrate according to an embodiment of the present invention.

FIG. 5 is a sectional view showing the structure of a substrate according to an embodiment of the present invention.

FIG. 6 is a sectional view showing the structure of a substrate according to an embodiment of the present invention.

[Explanation of symbols]

1 Hot plate whose surface is kept at about 100 ° C 2 Undercoated glass plate 3 Microfabricated ITO 4 Nematic liquid crystal with clearing point of about 80 ° C 5 Glass container 6 Substrate 7 Clearing point of about 80 ° C Nematic liquid crystal 8 Glass container 9 Electromagnetic pole piece 10 Substrate 11 Ethanol 12 Container 13 Undercoated glass plate 14 ITO electrode 15 2 Topcoat made of silicon oxide 16 Undercoated glass plate 17 ITO electrode 18 2 Made of silicon oxide Topcoat 19 Merck, vertical alignment agent, ultra-thin film by spinner coating of 0.2 wt% solution of ZLI-3334 20 Undercoated glass plate 21 ITO electrode 22 2 Topcoat made of silicon oxide 23 Organic resin film 24 Undercoated moth Substrate 25 ITO electrode 26 2 Topcoat made of silicon oxide 27 Organic resin film 28 Ultra-thin film by spinner coating of 0.2 wt% solution of ZLI-3334, vertical aligning agent, manufactured by Merck & Co., Inc. 29 Undercoated glass plate 30 ITO electrode 31 2 Top coat made of silicon oxide 32 Vertical alignment agent, ZLI-3334, was added to an organic resin.
Ultra thin film of mixed liquid added with 001% by weight

Claims (7)

[Claims] 1. A substrate and a substance exhibiting a liquid crystal state in a certain temperature range are heated, and this substance in an isotropic liquid state is brought into contact with the main surface of the substrate, and magnetic lines of force in a desired direction with respect to the substrate. The following singular or multiple processes, i.e., the process of lowering the temperature of this substance from an isotropic liquid state to a liquid crystal state, while exposing it to a magnetic field having a Holding the substrate at a high temperature, and then cleaning the substrate with an aqueous or alcoholic liquid for a short time to remove most of this material from the major surface, and then removing such a pair of substrates from the major surface. A liquid crystal panel, characterized in that they are opposed to each other and are bonded to each other with a predetermined gap therebetween, and this gap is filled with a predetermined liquid crystal composition. 2. The liquid crystal panel according to claim 1, wherein the substance contains a molecule having a functional group as an impurity. 3. A main surface of a substrate is an insulating oxide layer, or IT
The liquid crystal panel according to claim 1, comprising an O layer. 4. The main surface of the substrate is an insulating oxide layer, or I
2. A stack of a TO layer and a molecular layer having a functional group such as an alkoxysilane group at the end of the molecule and the other end having a structure similar to the nucleus of a low-molecular liquid crystal. LCD panel. 5. The liquid crystal panel according to claim 1, wherein the main surface of the substrate is made of an organic resin layer such as a polyimide resin layer, a polyparabanic acid resin layer, and a coupler layer. 6. The main surface of the substrate has an organic resin layer such as a polyimide resin layer, a polyparabanic acid resin layer or a coupler layer, and the end of the molecule has a functional group such as an alkoxysilane group, and the other end is low. The liquid crystal panel according to claim 1, comprising a laminated layer of molecular layers having a structure similar to the nucleus of the molecular liquid crystal. 7. A mixture layer of a main surface of a substrate with a polyimide resin and a molecule having a functional group such as an alkoxysilane group at the end of the molecule and a molecule having a structure similar to the core of a low-molecular liquid crystal at the other end. 2. The liquid crystal panel according to claim 1, comprising a mixture layer of an organic resin and the molecule, such as a mixture layer of a polyparabanic acid resin and the molecule, a mixture layer of a coupler and the molecule, or the like.