Alignment film, method of forming the alignment film, liquid crystal panel, and electronic equipment
View Patent ↗An alignment film for controlling orientation of liquid crystal molecules is formed of an organic silicon material which includes in its molecule an affinity imparting group for enhancing affinity to the liquid crystal molecules and an orientation characteristic imparting group for controlling orientation of the liquid crystal molecules. The affinity imparting group is at least one selected from the group comprising a vinyl group, an alkylene group, and a cyanoalkyl group, and the orientation characteristic group is at least one selected from the group comprising a phenyl group, a substituted phenyl group, a phenyl-alkyl group, a substituted phenyl-alkyl group, a branched alkyl group having carbon atoms of 3 to 12. Preferably, the organic silicon material includes organopolysilsesquioxane having a cage structure or a partially cleaved cage structure. A liquid crystal panel having the alignment film, and electronic equipment provided with the liquid crystal panel are also provided.
1. An alignment film for controlling orientation of liquid crystal molecules, the alignment film comprising:
an organopolysilsesquioxane as a main component of the alignment film, the organopolysilsesquioxane having in its molecule:
an affinity imparting group increasing affinity to the liquid crystal molecules; and
an orientation characteristic imparting group controlling orientation of the liquid crystal molecules,
wherein the organopolysilsesquioxane has a cage structure or a partially cleaved cage structure and is obtained by condensation polymerization of alkoxysilane consisting of alkoxysilane compounds having different compositions,
the alkoxysilane compounds having different compositions including:
a first alkoxysilane compound having in its molecule the affinity imparting group being at least one selected from the group consisting of vinyltrimethoxysilane and 3-cyanopropyltriethoxysilane,
a second alkoxysilane compound having in its molecule the orientation characteristic imparting group being at least one selected from the group consisting of phenyltrimethoxysilane and isobutyltrimethoxysilane, and
a third alkoxysilane compound having in its molecule a curing reaction group which contributes to a polymerization reaction of the organopolysilsesquioxane, wherein the curing reaction group is at least one selected from the group consisting of:
3-glycidoxylpropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane, wherein the alignment film is aligned by rubbing treatment.
2. The alignment film as claimed in claim 1 , wherein a weight average molecular weight of the organopolysilsesquioxane is in the range of 500 to 50,000.
3. A liquid crystal panel, comprising:
a liquid crystal layer having both sides;
a pair of alignment films respectively contacted at the both sides of the liquid crystal layer, each alignment film being formed from the alignment film defined in claim 1 ; and
a pair of electrodes provided on the alignment films respectively, for driving the liquid crystal molecules of the liquid crystal layer.
4. Electronic equipment provided with the liquid crystal panel defined by claim 3 .