Liquid crystal display device

Abstract

A liquid crystal display device having a pair of substrates, a liquid crystal layer, a group of electrodes for applying to the liquid crystal layer an electric field substantially parallel to the substrate surface, and a plurality of active elements connected to the electrodes, the group of electrodes and active elements being formed on one of the pair of substrates. An alignment control film is formed between the liquid crystal layer and at least one of the pair of substrates and is made from polyamic acid obtained by reacting a diamine with an acid anhydride. The acid anhydride is at least one member selected from the group consisting of 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride; 1,2,4,5-cyclehexanetetracarboxyic acid dianhydride; 3,3′,4,4′-biscyclohexanetetracarboxylic acid dianhydride; 3,3′,4,4′-benzophenonetetracarboxylic acid dianhydride; 1,2,3,4-butanetetracarboxylic acid dianhydride; and 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride and pyromellitic acid dianhydride.

What is claimed is:  
     
         1 . A liquid crystal display device comprising: 
 a pair of substrates at least one of which is transparent;    a liquid crystal layer disposed between said pair of substrates;    a group of electrodes for applying to said liquid crystal layer an electric field substantially parallel to a surface of at least one of said pair of substrates, and a plurality of active elements connected to said electrodes, said group of electrodes and active elements being formed on one of said pair of substrates; and    an alignment control film formed between said liquid crystal layer and at least one of said pair of substrates;    wherein said alignment control film is made from polyamic acid obtained by reacting a diamine with an acid anhydride, said acid anhydride being at least one member selected from the group consisting of:    1,2,3,4-cyclopentanetetracarboxylic acid dianhydride;    1,2,4,5-cyclehexanetetracarboxyic acid dianhydride;    3,3′,4,4′-biscyclohexanetetracarboxylic acid dianhydride;    3,3′,4,4′-benzophenonetetracarboxylic acid dianhydride;    1,2,3,4-butanetetracarboxylic acid dianhydride; and    1,2,3,4-cyclobutanetetracarboxylic acid dianhydride and pyromellitic acid dianhydride.    
     
     
         2 . A liquid crystal display device according to  claim 1 , wherein said acid anhydride is 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride.  
     
     
         3 . A liquid crystal display device according to  claim 1 , wherein said acid anhydride is a mixture of 1,2,3,4-butanetetracarboxylic acid dianhydride and 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride.  
     
     
         4 . A liquid crystal display device according to  claim 1 , wherein said alignment control film is aligned by irradiation with polarized light.