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Optical retardation film and method of production thereof

a technology of optical retardation film and liquid crystal display, which is applied in the direction of layered products, chemistry apparatus and processes, synthetic resin layered products, etc., can solve the problems of oblique viewing angle contrast ratio decrease, polarizers become uncrossed, and affect the quality of liquid crystal displays

Active Publication Date: 2014-05-27
CRYSOPTIX
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are still some disadvantages of LCD technology which impact the quality of liquid crystal displays.
One of disadvantages is a decrease of contrast ratio at oblique viewing angles.
However, at oblique angles the angle between projections of their axes deviates from 90°, and the polarizers become uncrossed.
This results in low contrast ratio at wide viewing angle along the bisector of crossed polarizers.
Moreover, liquid crystal cell placed between crossed polarizers makes leakage even higher.
However, their disadvantage is a low value of birefringence.
However, the described method has a technological drawback.
The last step severely restricts the product commercialization and does not allow using the plastic substrate for LCD manufacturing.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0053]This example describes synthesis of a rigid rod-like macromolecule of the general structural formula (I), wherein R1 is CH3, M is Cs and k is equal to n.

[0054]

[0055]30 g 4,4′-Diaminobiphenyl-2,2′-disulfonic acid was mixed with 300 ml pyridine. 60 ml of acetyl chloride was added to the mixture with stirring and the resulting reaction mass agitated for 2 hrs at 35-45° C. Then it was filtered, the filter cake was rinsed with 50 ml of pyridine and then washed with 1200 ml of ethanol. The obtained alcohol wet solid was dried at 60° C. Yield of 4,4′-bis(acetylamino)biphenyl-2,2′-disulfonic acid pyridinium salt is 95%.

[0056]12.6 g 4,4′-bis(acetylamino)biphenyl-2,2′-disulfonic acid pyridinium salt was mixed with 200 ml DMF. 3.4 g sodium hydride (60% dispersion in oil) was added. The reaction mass was agitated 16 hrs at room temperature. 7.6 ml methyl iodide was added and the reaction mass was stirred 16 hrs at room temperature. Then the volatile components of the reaction mixture were...

example 2

[0059]This example describes synthesis of a rigid rod-like macromolecule comprising n organic units of the first type having general structural formula I

[0060]

[0061]k organic units of the second type having general structural formula II

[0062]

[0063]wherein n is in the range from 0 to 10,000, and k is in the range from 0 to 10,000, sum n+k≧10, R1 is H, R2 is CH3, M is Cs. 4,4′-bis[methylamino]biphenyl-2,2′-disulfonic acid is obtained as described in Example 1. 0.8 g of 4,4′-bis[methylamino]biphenyl-2,2′-disulfonic acid, 0.72 g of 4,4′-bis[methylamino]biphenyl-2,2′-disulfonic acid and 3.29 g cesium bicarbonate were mixed with 6 ml water. This solution is stirred with IKA UltraTurrax T25 at 5 000 rpm for 2 min. 4.0 ml of toluene is added to the solution with stirring at 20 000 rpm for 5 sec. Then solution of 0.92 g terephthaloyl chloride in 2.0 ml of toluene is added to the mixture at 20000 rpm for 5 sec. The emulsion of polymer is stirred for 5 min.

[0064]The obtained foam plastic mass ...

example 3

[0068]This example describes preparation of a solid optical retardation layer of negative C-type from a solution of a rigid rod-like macromolecule according to the present invention.

[0069]2 g of organic compound produced as described in Example 2 was dissolved in 100 g of de-ionized water (conductivity ˜5 μSm / cm); the suspension was mixed with a magnet stirrer. After dissolving, the solution was filtered at the hydrophilic filter of a 45 μm pore size and evaporated to the viscous isotropic solution of concentration of solids of about 6%.

[0070]Fisher brand microscope glass slides were prepared for coating by soaking in a 10% NaOH solution for 30 min, rinsing with deionized water, and drying in airflow with the compressor. At a temperature of 22° C. and relative humidity of 55% the obtained LLC solution was applied onto the glass panel surface with a Gardner® wired stainless steel rod #14, which was moved at a linear velocity of about 10 mm / s. The solid optical layer was dried with a ...

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Abstract

The present invention relates generally to the field of organic chemistry and particularly to the optical retardation films for liquid crystal displays. The present invention provides an optical film comprising a substrate having front and rear surfaces, and at least one solid retardation layer on the front surface of the substrate. Said solid retardation layer comprises rigid rod-like macromolecules comprising n organic units of the first type having general structural formula I andk organic units of the second type having general structural formula II

Description

FIELD OF THE INVENTION[0001]The present invention relates generally to the field of organic chemistry and particularly to the optical retardation films for liquid crystal displays.BACKGROUND OF THE INVENTION[0002]The liquid crystal display (LCD) technology has made a remarkable progress in the past years. Cellular phones, laptops, monitors, TV sets and even public displays based on LCD panels are presented on the market. The market of LCD is expected to keep growing in the near future and sets new tasks for researchers and manufacturers. One of the key growth sustainers is product quality improvement along with cost reduction.[0003]LCD size has exceeded 100 inch by diagonal and it imposes stronger restrictions onto the quality of optical components. Retardation films should deliver a very small color shift and ability to provide higher contrast ratio at wide viewing angles in order to be used for high-quality viewing of large displays.[0004]There are still some disadvantages of LCD ...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): B32B27/40C08G75/30B32B27/00C08G75/00
Inventor KHARATIYAN, ELLINA
Owner CRYSOPTIX