Optical film, preparation method of the same, and liquid crystal display comprising the same

Abstract

The present invention relates to a composition for liquid crystal alignment layer, a preparation method of liquid crystal alignment layer using the same, and an optical film comprising the liquid crystal alignment layer. More particularly, the composition for liquid crystal alignment layer according to the present invention includes crosslinkable functional monomers as well as a photoreactive polymer, thereby improving thermal stability and durability of the liquid crystal alignment layer that is prepared by using the composition for liquid crystal alignment layer. In addition, when the liquid crystal alignment layer is used to produce an optical film, adhesive strength between substrate and liquid crystal alignment layer and between liquid crystal alignment layer and liquid crystal film can be improved.

Description

technical field [0001] The invention relates to an optical film, a preparation method of the optical film and a liquid crystal display comprising the optical film. [0002] This application claims priority to Korean Patent Application No. 10-2008-0005837 filed with the Korean Intellectual Property Office on January 18, 2008, the disclosure of which is incorporated herein by reference in its entirety. Background technique [0003] In general, optical films such as a retardation film and a viewing angle compensation film are disposed between a polarizing plate and a liquid crystal cell, so that a liquid crystal display (LCD) has a reduced color change and an increased viewing angle to improve brightness. The optical film is mainly classified into two kinds of films: one is a stretched film prepared by stretching a polymer film to obtain optical anisotropy, and the other is a film prepared by coating a plastic substrate with a polymerized liquid crystal compound and passing UV ...

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Problems solved by technology

However, when such an alignment layer is used, the liquid crystal film may peel off from the alignment layer or shrink due to insufficient adhesion between the alignment layer and the liquid crystal film in a hot and humid environment

In addition, when the rubbing method is used to prepare the alignment layer, there are some problems: electrostatic discharge may be caused due to contact with impurities during the rubbing process or defect sites may be caused, and fine dust may be generated by rubbing the fabric

However, the method for preparing the photo-alignment layer has a problem in that the use of commercially available solvents is limited, and a retardation film including the photo-alignment layer prepared by the above method must use acetyl cellulose as a substrate

The problems with this acetyl cellulose substrate are that light leakage may occur in the substrate due to its high hygroscopicity under hot and humid environments, and durability deterioration such as a decrease in the degree of polarization

There is still no report on the application of photo-alignment layers on the substrates of cycloolefin-based stretched films

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