JPH0346624A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To obtain the tilt orientation approximate to a homeotropic orientation by applying an orienting agent consisting of a mixture composed of a Ti compd. and Cr compd. on at least either of 1st and 2nd substrates, subjecting the coating to an orientation treatment and then rubbing the coating in a specified direction. CONSTITUTION:After the orienting agent 8 consisting of the mixture composed of the Ti compd. and the Cr compd. is applied on at least either of the 1st and 2nd substrates 5, 6, the coating is rubbed in the specified direction. Ti alkoxide compds., such as Ti(O-C3H7)4 and Ti(O-C4H9)4, or Ti acylate compds., etc., are preferably used as the Ti compd. Aliphat. carboxylic acid Cr complex, such as lactic acid and caproic acid, fluorine-substd. carboxylic acid Cr complex, such as perfluorononanoic acid, etc., are preferably used. The tilt orientation approximate to the homeotropic orientation which is heretofore difficult, i.e. the orientation of about 85 to 89.5 deg. pretilt angle is obtd. uniformly over a wide range.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to a liquid crystal display element, Regarding the orientation process.

Furthermore, [prior art] A liquid crystal display element using the conventional ECB mode consists of a liquid crystal cell in which a liquid crystal is sandwiched between two electrode substrates facing each other, as shown in FIG. It consists of a polarizing plate 1.4 arranged at .

In addition, an optically anisotropic body 2 other than the above liquid crystal may be further provided especially for viewing angle compensation.

The alignment of the liquid crystal molecules in the liquid crystal cell is a tilt alignment close to homeotropic alignment in the first substrate 5 and the second substrate 6, and the pretilt angle 11 is 8 degrees with respect to the substrate surface.
It is set at about 5 to 89.5 degrees. The purpose of this pretilt angle is to cause liquid crystal molecules to tilt in a certain direction when a voltage is applied to the liquid crystal cell.

[Problems and Objectives to be Solved by the Invention] However, in the conventional liquid crystal display element, it was necessary to use a complicated manufacturing method in order to realize the above-mentioned pretilt angle. The method is to obliquely deposit a metal oxide such as SiO at an angle of about 85° to the perpendicular direction of the substrate, and then
This is a method of applying a vertical alignment agent (Co-edited by Mitsuharu Okasho and Shunsuke Kobayashi, “Liquid Crystal Application Edition, Baifukan, p.61)”
However, oblique evaporation of SiO or the like is not suitable for mass production, and it is difficult to obtain uniform and large liquid crystal display cells.

Therefore, the present invention was made with the object of realizing the same orientation state as when using conventional oblique evaporation without using oblique evaporation, which is poor in mass production.

[Means for Solving the Problems] In order to achieve the above object, the present inventor has made earnest efforts and has arrived at the present invention.

That is, the liquid crystal display element of the present invention includes at least a first substrate provided with a transparent electrode, a second substrate provided with a transparent electrode, a liquid crystal sandwiched between the two substrates, and a liquid crystal sandwiched between them. In a liquid crystal display element consisting of a pair of polarizing plates arranged on both sides, after applying an alignment material made of a mixture of a T1 compound and a Cr compound to at least one of the first and second substrates. It is characterized by rubbing in a certain direction.

As a Ti compound, Ti(○-C3H7)4゜Ti
(OC4H9)4, Ti alkoxide compounds such as Ti(〇-(,+vH35)a, and partial hydrolysates of Ti alkoxide compounds, Ti(0-C3H?)α(O
COCI 7 H36)β, Ti(〇-Ca H7)α
Ti acylate compounds such as (QC(CH3)CHCOCH3,)β(α=1 to 3°β=4−α) are preferably used.

Preferred Cr compounds include aliphatic carboxylic acid Cr complexes such as butyric acid, caproic acid, pelargonic acid, capric acid, undecanoic acid, stearic acid, and myristic acid, and fluorine-substituted carboxylic acid Cr complexes such as perfluorononanoic acid. used.

The mixing ratio of these Ti compounds and Cr compounds is 1: l○
~10:1 (weight ratio) is preferably used.

[Example] Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 1 shows a cross-sectional view of a liquid crystal display cell in an embodiment of the present invention. In the figure, 1 is an upper polarizing plate and 4 is a lower polarizing plate.

The two polarizing plates have a so-called crossed nicol relationship in which their absorption axes are orthogonal to each other. Further, the absorption axis direction of the upper polarizing plate forms an angle of 45'' with the rubbing direction of the first substrate of the adjacent liquid crystal cell.

The first substrate 5 and the second substrate 6 of the liquid crystal cell are subjected to vertical alignment treatment and then rubbed.

In the vertical alignment process, a mixture of myristic acid Or complex and T i (OC2HI+) 4 (mixing ratio 1) was used as a vertical alignment agent.
:1 weight ratio) was used.

Next, the surface of the substrate that had been subjected to the vertical alignment treatment was rubbed. The rubbing was performed once under a load of 2 kg using fixed rubbing using a nylon flocked cloth. The rubbing directions were set to be opposite between the first and second substrates. As for the rubbing method, it was possible to create similar products by fixed rubbing using rayon flocked cloth or bleached cloth, or rotating rubbing.

The thus obtained substrate was assembled into a cell, and liquid crystal was sealed. Cell gap d was set to 6.0 μm. As the liquid crystal 10, ZL Any 318 (n-type liquid crystal Δε=−2,0Δn=0.1243) manufactured by Merck was used.

The pretilt angle of the obtained liquid crystal cell was 87 degrees (the pretilt angle was measured by the crystal rotation method in a magnetic field).

The contrast ratio of the liquid crystal display cell obtained in this way is
The contrast ratio was approximately 1:180 in the cell normal direction, and a uniform and good contrast ratio was obtained throughout the cell.

[Effects of the Invention] As described above, according to the present invention, tilt alignment close to homeotropic alignment, which has been difficult in the past, that is, alignment with a pretilt angle of about 85 to 89.5 degrees, can be achieved uniformly and over a wide range. obtained over a period of time.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a conventional liquid crystal display cell, and FIG. 2 is a cross-sectional view of a liquid height display cell according to an embodiment of the present invention. Upper polarizing plate Optically anisotropic lower polarizing plate First substrate Second substrate Transparent electrode SiO Oblique vapor deposition film Aligning agent N-type nematic liquid crystal Pre-tilt angle sealing agent for liquid crystal molecules

Claims (1)

[Claims] At least a first substrate provided with a transparent electrode, a second substrate provided with a transparent electrode, a liquid crystal sandwiched between the two substrates, and a pair of polarized lights disposed on both sides of the substrate. In a liquid crystal display element consisting of a plate, at least one of the first and second substrates is coated with a Ti compound and a Cr.
1. A liquid crystal display element characterized by being subjected to an alignment treatment using an alignment agent made of a mixture of compounds and then being rubbed in a certain direction.