Hana Microdisplay Technologies, Inc.

Michael Stefanov

James E Anderson

Jignesh V Gandhi

The invention involves a novel method and structure for utilizing homeotropic vertically aligned nematic liquid crystal cells in the production of high contrast microdisplays. Two circular polarizers are used in order to propagate circularly polarized, rather than planar polarized, light through a liquid crystal cell. The use of circularly polarized light eliminates the liquid crystal director alignment requirements for the transmittance of light necessary for planar polarized light. With no director alignment requirement, it is possible to use perfectly homeotropic vertically aligned nematic cells irrespective of domain size and shape because fringing field induced director tilt will not decrease the transmittance of the liquid crystal cell.

High contrast reflective light valve

A high contrast twisted nematic liquid crystal cell in which outgoing or reflected light is linearly polarized and has the same polarization angle as incoming or incident light when the cell is in an off state. Matching the polarization axes of incoming and outgoing light allows less light to pass through a final analyzer with the cell in an off state to provide a darker off state, and allows more light through with the cell in an on state, resulting in an enhanced contrast ratio display. A method of determining placement of optical retarders for enhanced contrast in a reflective twisted nematic liquid crystal display device is also described.

Growing community of inventors

Stow, OH, United States of America

Michael Stefanov