Polymer sustained alignment for vertical aligned liquid crystal devices with a fast response and high contrast

ABSTRACT

We demonstrate fast response and high contrast vertical alignment (VA) liquid crystal devices (LCDs) with polymer sustained alignment (PSA). In general, the rise time of a liquid crystal (LC) is a trade-off relationship with the decay time. In the present study, an appropriate tilt angle of LCs was anchored by polymerisation using UV irradiation with the application of a threshold voltage and optimisation of the reactive mesogen (RM) concentration. The PSA VA-LCDs showed a fast optical response to the applied electric field because the backflow (optical bounce) was suppressed by anchoring with the polymer. In addition, the fast response was maintained until a high voltage was applied. The transmittance of these PSA VA-LCDs at 0 V was identical to that of VA-LCDs without a polymer and the opaque phenomena at the applied voltage were eliminated because alignment of LCs and RMs was improved. The findings of this work are expected to enable the development of displays and phase modulators with improved performance.

GRAPHICAL ABSTRACT

KEYWORDS:

• Fast response
• polymer sustained alignment
• vertical alignment
• high contrast

Acknowledgement

The authors are grateful to Merck for providing the LC materials, DIC for the reactive mesogens, and Nissan Chemical Corp. for the polyimide materials.

Disclosure statement

No potential conflict of interest was reported by the author(s).