Fabrication of Defect-Free Surface-Stabilized Ferroelectric Liquid Crystals Using Alignment Films Rubbed in Anti-Parallel

Abstract

Fabrication of operable surface-stabilized ferroelectric liquid crystals (SSFLC) is often hampered by the occurance of zigzag defects. This defect formation can, to some extent, be controlled or eliminated in SSFLCs in which the rubbing directions are set parallel. In this study, we try to fabricate a defect-free SSFLC with anti-parallel rubbing films which possess different surface anchoring and pretilt angle between two cell substrates in order for the energy condition in two types of chevron to be different. It is confirmed that in all alignment films used in this research, the occurrence of zigzag defects can be suppressed as the difference of rubbing strengths increases between two alignment films. Furthermore, it is found that the appearance of zigzag defects can be more strongly suppressed as the difference of pretilt angles increases between two alignment films, and then in the case of the large difference, zigzag defect-free SSFLCs can be obtained.

Keywords:

• Ferroelectric liquid crystal
• zigzag defect
• anti-parallel rubbing
• surface anchoring
• pretilt angle

Acknowledgment

The authors thank Mr. H. Fukuro and Mr. H. Endoh of Nissan Chem Ind. for supplying polyimide materials.