JPH049007A - Liquid crystal elements and their manufacturing method - Google Patents

Abstract

PURPOSE:To orient liquid crystal molecules without producing dust by forming layers of solid organic molecules arrayed on at least one main-surface side of substrates, and sandwiching a specific liquid crystal compound with the substrates. CONSTITUTION:The layers 5 and 6 are formed of arrayed solid organic molecules on at least one main-surface side of at least the 1st substrate 1 and 2nd substrate 2, between which a ferroelectric liquid crystal composition, or P type nematic liquid crystal composition, or N type nematic liquid crystal composition is sandwiched. On the layers 5 and 6 consisting of the oriented solid organic molecules, liquid crystal molecules (P type nematic liquid crystal composition, N type liquid crystal composition, ferroelectric liquid crystal composition, etc.) are oriented. Consequently, the requested superior orientation of the liquid crystal molecules is obtained and the production of dust, etc., is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid crystal element and its manufacturing method. In particular, it relates to the alignment of liquid crystal molecules.

BACKGROUND OF THE INVENTION A liquid crystal molecule alignment film is essential for liquid crystal displays.

As the alignment film, an inorganic obliquely evaporated film, a polymer resin film rubbed with 4J, etc. is used (Basics and Applications of Liquid Crystal Electronics, edited by Akio Sasaki). Polyimide is mainly used as the polymer resin.

Problems to be Solved by the Invention The oblique evaporation method requires too much production cost and is not a practical method.

Problems caused by a polymer resin film that has been rubbed with cloth or the like will be described below. First of all, dust and the like are generated due to friction, which causes a decrease in production yield. Second, in order to achieve an alignment with a high pretilt angle of liquid crystal molecules, there are many problems such as streaks appearing in the display of the liquid crystal element and poor reproducibility of the pretilt angle. These problems also occur in STN mode, homeo mode, and 5SFLC mode using ferroelectric liquid crystal.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention forms a layer made of arranged solid organic molecules on the main surface of at least one of the first substrate and the second substrate. The present invention provides a liquid crystal element characterized in that a ferroelectric liquid crystal composition, a P-type nematic liquid crystal composition, or an N-type nematic liquid crystal composition is sandwiched between the substrates.

The present invention also provides a method of forming a layer made of arranged solid organic molecules on at least one of the main surfaces of the first substrate and the second substrate, further forming a vertical alignment agent layer thereon, and forming a vertical alignment agent layer on the main surface of at least one of the first substrate and the second substrate. The present invention provides a liquid crystal element characterized by sandwiching a ferroelectric liquid crystal composition or an N-type nematic liquid crystal composition.

It is necessary to select one in which the aromatic compound hardly dissolves in the liquid crystal composition, and this is related to the liquid crystal composition used.

Desirable solid organic molecules have a liquid crystal state at high temperatures and are substantially insoluble in ferroelectric liquid crystal compositions, P-type nematic liquid crystal compositions, or N-type nematic liquid crystal compositions.

A method for manufacturing such a liquid crystal element is to form a layer made of solid organic molecules on a substrate, and then heat and cool the substrate while applying a DC magnetic field of a predetermined intensity in a predetermined direction. Therefore, it was effective to solidify this layer of solid organic molecules from a liquid crystal state.

A solid organic molecule having a liquid crystal state in a high-temperature region is dissolved in a solvent on a substrate to form a layer by coating, or the solid organic molecule is heated and dissolved to form a layer by coating;
Next, the layer is heated to a liquid crystal state, and at the same time, in a predetermined direction,
A direct current magnetic field of a predetermined intensity is applied, the substrate is cooled as it is, and the layer is solidified. X-ray diffraction revealed that this solidified layer was oriented. This was the first step leading to the present invention.

The present invention further provides that liquid crystal molecules (P-type nematic liquid crystal composition, N
The origin of this invention lies in the discovery that liquid crystal compositions (such as ferroelectric liquid crystal compositions) are oriented. Furthermore, it has been found that by appropriately setting the strength and direction of the magnetic field, reproducibility in high pretilt liquid crystal molecular alignment, which has been insufficient up to now, can be ensured.

Forming a layer of oriented solid organic molecules on a substrate,
Furthermore, it has been found that uniform alignment is possible when a vertical alignment agent is applied thereon and a ferroelectric liquid crystal composition or an N-type nematic liquid crystal composition is sandwiched between the substrates.

The present invention was made based on such a discovery, and uses the above-mentioned solid organic molecules in a liquid crystal element, thereby eliminating the generation of dust during the alignment process and increasing the production yield. Second, even when the liquid crystal molecules are aligned with a high pretilt angle, streaks do not occur in the display of the liquid crystal element, and the reproducibility of the pretilt angle is improved.

This will greatly contribute to production in STN mode, homeo mode, and 5SFLC mode using ferroelectric liquid crystal.

Example The present invention will be explained in detail below.

FIGS. 1 and 2 are cross-sectional views showing a liquid crystal element obtained by an embodiment of the present invention. In the figure, 1 and 2 are, for example, first and second substrates made of transparent glass, 3.4 is a rectangular transparent conductive electrode made of, for example, an ITO film on the main surface, and 5.6 is an oriented solid. These are layers made of organic molecules, and 7 is a liquid crystal layer, and 89 is an alignment film with vertical alignment.

Example 1 P-quinque phenyl, one of solid organic molecules dissolved in phenol, was applied by dip method to the main surfaces of glass substrates 1 and 2 having microfabricated ITO electrodes 3 and 4 as base materials, and the solvent phenol was applied. It evaporates.

Next, the substrate was placed in a nitrogen atmosphere in a high-temperature bath, and
The substrate is heated to 0° C., and a DC magnetic field of approximately 100° Gauss is applied at an angle of approximately 30° from the substrate surface. At this time, the layer made of p-quinphenyl is in a liquid crystal state.

In this state, that is, while applying a magnetic field, the layer consisting of P-quinphenyl is solidified by slow cooling (corresponding to Figure 1).
.

As a result of an X-ray diffraction experiment of the obtained film, it was found that the layer consisting of p-quinquephenyl was present, although the orientation was weak.

Glass substrates 1 and 2 were bonded together in a predetermined manner, and a liquid crystal composition was injected into the gap 1 to obtain a liquid crystal element. As the seal, t, JV curing resin was used. ST liquid crystal composition
When a liquid crystal composition for N (super twisted TN) was prepared, it was confirmed by optical properties, pretilt measurements, etc. that the alignment was a uniform tilt alignment.

The display characteristics were also excellent, with no streaks or the like. Furthermore, when the liquid crystal composition was a ferroelectric liquid crystal composition, stable uniform alignment was obtained and the display was excellent. However, in this case, the gap was about 2 microns.

Further, the same procedure was carried out for p,p'-cyamic meter phenyl and dimethyl-p,p'-dioxyterphenyl. Some of the results were better, some were worse, but as before, they were better than before.

Note that it is desirable that the solid organic molecules have almost no compatibility with the liquid crystal composition used. For example, Pp'-bis(biphenylcarbinol)biphenyl dimethyl-p,p
-Dioxyterphenyl.

p, p'-diaminoquaterphenyl, quinphenyl, dibenzal-p, p'-diaminoquaterphenyl, di-p-methoxybenzoyl disulfide, etc. are easy to use (``Production method and application of liquid crystals'', published by Sachi Shobo, Nakata part, Fumi Hori (Author, Reference).

Example 2 An experiment similar to Example 1 was conducted. However, the glass substrate 1 having the base material and the microfabricated IT○ electrodes 3 and 4 of U7
．． 2, heat the substrate to about 180°C, p, p'
−Bis(biphenylcarbinol)biphenyl is melted (
In this case, it was in a liquid crystal state) and was applied. The atmosphere was nitrogen. During this heating and cooling, the direction of the applied magnetic field was about 5°.

Next, Vertical Aligner Z manufactured by Merck Co., Ltd. 1. ,, I-312
4 was applied using a spinner and dried (corresponding to Figure 2).

A liquid crystal element was obtained by filling the gap with N-type nematic liquid crystal. The orientation of the liquid crystal molecules was uniform, there were no streaks in the display, and the reliability was sufficient. Note that it is desirable that the layer made of this vertical alignment agent has a thickness of about 300 angstroms or less.

Example 3 P and p diaminoquaterphenyl were applied in the same manner as in Example 1 to the main surfaces of glass substrates 1 and 2 having microfabricated ITO electrodes 3 and 4, respectively. This is heated to about 210°C and then slowly cooled to solidify. At this time, a DC magnetic field of about 100 Gauss was applied at an angle of about 88° from the substrate surface (corresponding to Figure 1).
.

As a result of an X-ray diffraction experiment of the obtained film, it was found that the film had weak orientation.

Glass substrates 1 and 2 were bonded together in a predetermined manner, and a liquid crystal composition was injected into the gap to obtain a liquid crystal element. As a sticker,
A UV curing resin was used. When the liquid crystal composition was an N-type nematic liquid crystal composition, it was confirmed by optical properties, pretilt measurements, etc. that the alignment was a uniform, slightly tilted vertical alignment. The display characteristics were also excellent, with no streaks or the like.

Example 4 Using a vapor deposition apparatus with a vacuum level of about 10' Torr, p
Quinphenyl was placed on a heater equipped with a heater and sublimated, thereby depositing the organic molecules on the main surface of the cold glass substrate where ITO was present. The boat was made sure not to overheat.

Next, this substrate was heated to about 410°C and slowly cooled to solidify.

At this time, at the same time, a DC magnetic field of about 100 Gauss was applied to the glass substrate at an angle of about 106 with respect to the substrate surface (corresponding to FIG. 1).

As a result of an X-ray diffraction experiment of the obtained film, it was found that the film had weak orientation, but it was found to exist.

Glass substrates 1.2 were bonded together in a predetermined manner, and a liquid crystal composition was injected into the gap to obtain a liquid crystal element. As a sticker,
A UV curing resin was used. When the liquid crystal composition was used as a liquid crystal composition for STN (super twisted TN), it was confirmed by optical properties, pretilt measurements, etc. that the alignment was a uniform tilt alignment.

The display characteristics were also excellent, with no streaks or the like. Furthermore, when the liquid crystal composition was a ferroelectric liquid crystal composition, stable uniform alignment was obtained and the display was excellent. However, in this case, the gap was about 2 microns.

Effects of the Invention The present invention makes it possible to obtain the required excellent alignment of liquid crystal molecules through appropriate structure and processing, and furthermore, does not generate dust or the like, making it a great contribution to industry.

[Brief explanation of the drawing]

1 and 2 are schematic cross-sectional views of a liquid crystal element obtained according to an embodiment of the present invention. ■...First board, 2...Second board, 3
, 4... Transparent conductive electrode, 5, 6...
Layer consisting of oriented solid organic molecules, 7...Liquid crystal layer, 8, 9...Vertical alignment alignment film. Name of agent: Patent attorney Shigetaka Awano (1 person)

Claims (4)

[Claims] (1) A layer made of aligned solid organic molecules is formed on at least one of the main surfaces of the first substrate and the second substrate, and the substrate is made of a ferroelectric liquid crystal composition or a P-type nematic liquid crystal composition. Or a liquid crystal element characterized by sandwiching an N-type nematic liquid crystal composition. (2) Forming a layer made of aligned solid organic molecules on at least the main surface of at least one of the first substrate and the second substrate, further forming a vertical alignment agent layer thereon, and A liquid crystal element comprising a dielectric liquid crystal composition or an N-type nematic liquid crystal composition. (3) A claim characterized in that the solid organic molecule has a liquid crystal state in a high temperature range and is hardly dissolved in a ferroelectric liquid crystal composition, a P-type nematic liquid crystal composition, or an N-type nematic liquid crystal composition. Item (1) or (2)
The liquid crystal element described. (4) Forming a layer made of solid organic molecules on a substrate, and then heating and cooling the substrate while applying a DC magnetic field of a predetermined intensity in a predetermined direction. 2. The method for manufacturing a liquid crystal element according to claim 1, wherein the layer consisting of the above is solidified from a liquid crystal state.