Vertically aligned nematic mode liquid crystal display having large tilt angles and high contrast

摘要

A reflective liquid crystal on silicon (LCOS) display comprises a transparent substrate, a reflective substrate, and liquid crystal fluid between the substrates. The LCOS display further comprises a matrix of pixels, arranged in a plurality of rows and columns, wherein an intersection of a row and a column defines a position of a pixel in the matrix. The LCOS display has tilt angles sufficient to overcome disclinations due to fringe fields, and, at the same time, achieves high contrast. The surface azimuthal direction of the molecules of the liquid crystal fluid is either substantially parallel or perpendicular to the direction of polarization of incoming incident linearly polarized light. Light leakage is minimal because the effective birefringence as seen by the incoming incident linearly polarized light is substantially zero and does not depend on the pretilt of the molecules of the liquid crystal fluid. Between the transparent substrate and the reflective substrate, the twist of the molecules of the liquid crystal fluid may vary from about 0 degrees to about 90 degrees when in the “OFF” state.

主权项

1. A reflective liquid crystal display, comprising:
a first substrate that is substantially transparent; a second substrate that is substantially reflective and substantially parallel with said first substrate; and a chiral-dopant free liquid crystal fluid having a birefringence (Δn) and a negative dielectric anisotropy, wherein said chiral-dopant free liquid crystal fluid is between said first and second substrates; said first substrate having a first liquid crystal alignment layer proximate to said chiral-dopant free liquid crystal fluid, wherein molecules of said chiral-dopant free liquid crystal fluid that are proximate to the first liquid crystal alignment layer have a first pretilt angle from about 5 degrees to about 15 degrees and a first azimuthal direction; said second substrate having a second liquid crystal alignment layer proximate to said chiral-dopant free liquid crystal fluid, wherein molecules of said chiral-dopant free liquid crystal fluid that are proximate to the second liquid crystal alignment layer have a second pretilt angle from about 5 degrees to about 15 degrees and a second azimuthal direction, the second azimuthal direction being substantially perpendicular to the first azimuthal direction.