High Contrast and Fast Response Polarization- Independent Reflective Display Using a Dye-Doped Dual-Frequency Liquid Crystal Gel Yi-Hsin Lin Hongwen Ren Sebastian Gauza Yung-Hsun Wu Ying Zhou Shin-Tson Wu College of Optics and Photonics, University of Central Florida, Orlando, Florida, USA We have developed a new guest-host reflective display using a dye-doped dual- frequency liquid crystal (DFLC) gel. By combining dye absorption and maximal light scattering, the display is polarization independent and exhibits a high con- trast (  230:1). The high reflectivity (R  50%) is because of the vertical aligned structure at 0 V rms . The fast response time (  5 ms) is also fast due to the frequency modulation. A black and white segmented-alphabet reflective display prototype is also demonstrated. Keywords: dual frequency liquid crystal; gel; guest-host reflective display; high contrast; polarization-independent I. INTRODUCTION Guest-host liquid crystal displays (GH LCDs) do not require any polar- izer; therefore, they exhibit a high brightness and wide viewing angle [1,2]. Several device configurations such as Cole-Kashnow cell [3], White-Taylor cell [4], or double orthogonal cells [5–7] have been pro- posed for achieving polarization independence. A typical reflectance of the GH LCD is  50%, but the contrast ratio is only  5:1, limited by the dichroic ratio (typically 10:1) of the employed dyes. Increasing This work was supported by Toppoly Optoelectronics (Taiwan). Address correspondence to Yi-Hsin Lin, College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816, USA. E-mail: swu@mail.ucf.edu Mol. Cryst. Liq. Cryst., Vol. 453, pp. 371–378, 2006 Copyright # Taylor & Francis Group, LLC ISSN: 1542-1406 print=1563-5287 online DOI: 10.1080/15421400600653902 371