New photoactive polymers, their use as liquid crystal (LC) orientation layers and their use in the construction of unstructured and structured optical and electro-optical elements and multi-layer systems. The new photoactive polymers are crosslinkable polymers that can be readily cross linked over a relatively short irradiation time.
This application is a national stage filing under 35 U.S.C. .sctn. 371 of international application no. PCT/EP00/06788, filed on Jul. 17, 2000, which published in the English language. This application also claims the benefit of priority under 35 U.S.C. .sctn. 119(a) to European patent application no. 99305857.7, filed on Jul. 23, 1999.
A liquid crystal alignment treating agent for optical alignment treatment, whereby it is possible to obtain a liquid crystal alignment film which presents a high and stable tilt angle of liquid crystal and which is excellent in an accumulated charge property by a DC voltage, is provided.A liquid crystal alignment treating agent which comprises, as resin components, a polyimide precursor or a polyimide obtained by cyclodehydration of the polyimide precursor, and an acryl polymer having repeating units represented by the formula (II): ##STR00001## (wherein R.sup.3 represents a hydrogen atom, a methyl group or a halogen atom, R.sup.4 represents an alkyl group having at least 8 carbon atoms, and k represents a positive represented by the formula (III): ##STR00002## (wherein R.sup.3 and R.sup.5 each independently represents a hydrogen atom, a methyl group or a halogen atom, R.sup.4 represents an alkyl group having at least 8 carbon atoms, R.sup.6 represents an organic group having an epoxy group, and k and j each represents a positive integer), wherein the acryl polymer having the repeating units represented by the formula (II) or the formula (III) is from 0.01 to 30 wt % based on the whole resin components.
The present invention provides an optical element capable of improving the adhesive property between a refractive index anisotropic layer and an alignment property providing layer for providing alignment property to the refractive index anisotropic layer and further improving the endurance of each of the layers.
