Liquid Crystal Materials for Matrix Displays.
Abstract
Studies are made on improved liquid crystal (LC) materials for use in MOSFET matrix displays operated with dc-activated dynamic-scattering (DS). The results provide a basis for development of nematic LC materials capable of wide-temperature-range storage, dc operation at elevated temperatures (35 to 71 C), and long lifetime displays. LC structural effects are evaluated by using different combinations of components from eight classes of esters, including phenyl benzoates, phenyl thiobenzoates, phenyl cyclohexanecarboxylates, phenyl acyloxybenzoates, a phenyl benzoyloxybenzoate, and a phenyl biphenylcarboxylate structure. Six mixtures are characterized at 25 C, and their viscosity, dielectric anisotropy, conductivity anisotropy, and dc-activated DS effects are studied at elevated temperature. Three mixtures are thermally stable at 100 C in evacuated tubes, with redox dopants present. Their dc-DS stability is studied at 55 C, both in transparent cells and in cells with reflective metal electrodes. Correlations from these studies provide a good basis for further optimization of LCs for matrix displays. However, additional studies are needed on thermal instability problems caused by reactions with glass surfaces and with organic sealants in display cells at elevated temperatures. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1981
- Accession Number
- ADA098307
Entities
People
- Anna M. Lackner
- J. David Margerum
Organizations
- HRL Laboratories