Laser-based displays suffer from speckle noise due to the random inference patterns of scattered coherent light from rough surfaces. Commonly utilized solution, such as moving diffusers, creates time-varying speckle patterns that were averaged on the observer’s retina or the image sensor. This solution requires the use of motorized parts and can be bulky with the potential risk of mechanical failure. We present a liquid crystal device that reduces speckle noise by over 90%. It is electrically driven, compact, and with no motorized parts. The randomized, time-varying domains with mismatched refractive indices of the liquid crystals produce varying speckle patterns. A near zero speckle contrast is achieved.
We briefly review systematic and comprehensive studies on several chlorine-substituted bent-core liquid crystal materials
in their nematic phases. The results, in comparison to rod-shaped molecules, are both extraordinary and technologically
a) Electrohydrodynamic instabilities provide unique patterns including well defined, periodic stripes and optically isotropic
b) Rheological measurements using different probe techniques (dynamic light scattering, pulsed magnetic field, electrorotation)
reveal that the ratio of the flow and rotational viscosities are over two orders of magnitudes larger in bentcore
than in calamitic materials which proves that the molecule shape and not its size is responsible for this behaviour.
c) Giant flexoelectric response, as measured by dynamic light scattering and by directly probing the induced current
when the material is subject to oscillatory bend deformation, turns out to be more than three orders of magnitude larger
than in calamitics and 50 times larger than molecular shape considerations alone would predict. The magnitude of this
effect renders these materials as promising candidates for efficient conversion between mechanical and electrical energy.
d) The converse of this effect when the bent-core material sandwiched between plastic substrates 4 times thicker than the
liquid crystal material provided displacements in the range of 100nm that is sensitive to the polarity of the applied
field thus suggesting applications as beam steering and precision motion controls.