LIQUID CRYSTAL DEVICES WITH REDUCED SURFACE ANCHORING ENERGY

摘要

Smectic liquid crystal devices are formed by a layer of a smectic liquid crystal material (20) enclosed between two cell walls (2, 3), both carrying electrode structures (5, 6, 7) to switch the liquid crystal material between two states. One wall (3) is treated to align molecules of the liquid crystal material with a required amount of surface tilt, e.g. zero to about 30°. The other wall (2) is treated to give no alignment direction with a surface tilt of zero to about 30° together with either zero or a low surface anchoring energy to contacting liquid crystal molecules. This allows the liquid crystal material to align into micro layers forming a uniform tilted bookshelf type formation. The low surface anchoring energy is provided by a two layer treatment; a first bonding layer (23) and a second layer (24) formed by monomer layer which is polymerised and preferably heated to about melting point. The device has an analogue response to voltage. The method may be applied to devices using nematic and cholesteric liquid crystal material.