Bistable Switchable Liquid Crystal Window

KSU.302

Abstract: We invented a bistable switchable liquid crystal window which can be switched between a transparent state and a milky state by a one-second-wide voltage pulse.  No voltage has to be applied to sustain the optical states, and therefore this window is very energy-saving.  This switchable window is based on polymer stabilized cholesteric texture (PSCT) liquid crystal technology which is owned by Kent State University.  The transparent state is the homeotropic state where the liquid crystal is uniformly aligned in the cell normal direction.  The scattering state is the focal conic state where the liquid crystal exists in randomly oriented poly-domains.  With proper polymer networks, both the homeotropic and focal conic states are stabilized at zero field.  The liquid crystal used exhibits dual dielectric anisotropies.  One advantage also is greater clarity than with former polymer dispersed liquid crystal (PDLC) switchable window technology

Applications: In exterior or interior settings for privacy (such as in offices, conference rooms, hospital areas, bathrooms/showers, etc.) and for sun/heat control (such as buildings, greenhouses, automobiles for sunroofs, side windows on aircraft) and many other purposes.

Advantages: The main advantage over previous technologies is in energy saving.  Although this may be of small concern in some applications, for building-wide applications, or where energy is very limited, the energy savings feature is significant.

Inventors: Dr. Deng-Ke Yang and Lei Shi