Self-alignment technique of liquid crystal using a novel additive containing thiol group

Abstract

Self-aligned vertical alignment (SA-VA) technique in liquid crystal display (LCD), in which the alignment layer coating process is not necessary, has attracted significant attention owing to its cost-effectiveness and usefulness in the control of LC alignment and the fabrication of LCDs. However, it presents a critical drawback pertaining to the occurrence of LC alignment defects caused by non-uniform additive attachment on the surface; as a result, the technology has not yet been adopted for commercial applications. Here, we propose an advanced SA-VA technology using novel additives containing thiol groups and thermally induced physicochemical adsorption of additives on the surface. Using the new materials as well as method, we successfully demonstrate a perfect vertical alignment of LC without non-uniform alignment defects. In addition, it is confirmed that the electro-optical performance of the cell is comparable to that of a conventional commercial device. Thus, our method can overcome the limitation of existing SA-VA technology, and may be applied to commercial SA-VA mode displays. Further, with its self-alignment feature, the technology may be useful for the future display applications such as cost-effective smart window using LC.