Electrically‐Triggered Oblique Helicoidal Cholesterics with a Single‐Layer Architecture for Next‐Generation Full‐Color Reflective Displays

Abstract Electrically‐induced oblique helicoidal cholesterics (Ch OH ) are attractive for use in reflective displays due to tunable photonic band gap (PBG) in a broad spectral range and natural eye‐friendly feature. However, the lack of a stable liquid crystal (LC) material system with a wide temperature range and unknown driver architecture hinder the implementation of the Ch OH ‐based reflective displays. Here, a prototype for a full‐color reflective display device based on electrically‐tunable Ch OH ‐LC is demonstrated. In the comparison of Ch OH ‐S1, S2 and S3 samples, the electric‐field‐induced Ch OH in the Ch OH ‐S3 exhibits intense Bragg reflection and a tunable PBG in the extended temperature range from 19.5 °C to 30 °C. Particularly, the resulting device exhibits a lower driving voltage and a relatively larger color gamut for the full‐color reflective displays. On this basis, the display patterns with variable colors are demonstrated via the direct addressing mode. Furthermore, a proof‐of‐concept of the full‐color reflective display is demonstrated with red‐green‐blue pixeled images serving as the active panels. Ultimately, by regulating the electric field strength dependent on the ambient temperature, a stable and vivid effect of the Ch OH device on the actual environment is shown. This work provides valuable insight for the development of Ch OH ‐based reflective displays.