Optical devices having flakes suspended in a host fluid to provide a flake/fluid system providing flakes with angularly dependent optical properties in response to an alternating current electric field due to the dielectric properties of the system
First Claim
1. An optical device comprising a suspension of flakes with angularly dependent optical properties, the suspending liquid having a conductivity that differs from the conductivity of the material of the flakes and having a magnitude of at least about 10−
- 7 Mho/cm.
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Accused Products
Abstract
Optical devices utilizing flakes (also called platelets) suspended in a host fluid have optical characteristics, such as reflective properties, which are angular dependent in response to an AC field. The reflectivity may be Bragg-like, and the characteristics are obtained through the use of flakes of liquid crystal material, such as polymer liquid crystal (PLC) materials including polymer cholesteric liquid crystal (PCLC) and polymer nematic liquid crystal (PNLC) material or birefringent polymers (BP). The host fluid may be propylene carbonate, poly(ethylene glycol) or other fluids or fluid mixtures having fluid conductivity to support conductivity in the flake/host system. AC field dependent rotation of 90° can be obtained at rates and field intensities dependent upon the frequency and magnitude of the AC field. The devices are useful in providing displays, polarizers, filters, spatial light modulators and wherever switchable polarizing, reflecting, and transmission properties are desired.
58 Citations
40 Claims
- 1. An optical device comprising a suspension of flakes with angularly dependent optical properties, the suspending liquid having a conductivity that differs from the conductivity of the material of the flakes and having a magnitude of at least about 10−
- 22. An optical device comprising a suspension of flakes which are of polymer liquid crystal material and have angularly dependent optical properties in response to an AC field in response to the dielectric properties of the suspension of flakes.
- 32. An optical device comprising a suspension of flakes which are of birefringent polymer material having dielectric properties which provide said flakes with angularly dependent optical properties in response to an AC field.
Specification