Multistable cholesteric liquid crystal devices driven by width-dependent voltage pulse
US5889566A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 17, 1997 |
| Grant date | Mar 30, 1999 |
| Priority date | — |
| Expiry date | Apr 17, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F3/022
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A light modulating apparatus containing cholesteric liquid crystals capable of indefinite zero field retention of optical images, including full color and complete gray scale capability, is described. This invention is predicated on establishment of zero field multistable liquid crystal domains representing a continuous distribution of states ranging from the highly reflective planar to the light-scattering focal-conic structures. The zero field multistable domain structure stability is achieved by controlling solid surface-liquid crystal boundary interactions to provide essential equalization of the total system energy of each of the domain structures. This is the first time this equalization, and thus zero field multistability, has been achieved without the use of a polymer gel addition to create rigid polydomains in the liquid crystal mix. The establishment of a particular domain structure, and thus the degree of light reflection or scattering by individual display pixels, is controlled using either a single relatively long voltage pulse or a number of shorter duration successive voltage pulses. The zero field multistability achieved is remarkably stable against both mechanical …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.