Université de Neuchâtel

Improved red color with cholesteric liquid crystals in Bragg reflection mode

Kipfer, Peter ; Klappert, Rolf ; Herzig, Hans-Peter ; Grupp, Joachim ; Dändliker, René

In: Optical Engineering, 2002, vol. 41, no. 3, p. 638-646

The helical pitch of the cholesteric liquid crystal (CLC) can be adjusted to reflect the colors red, green, and blue. Additive mixing of these colors in displays results in multicolor images and it is easy to use pure primary blue and green colors, but the red color is in general very unsaturated. We show by simulations that this poor red color performance is due to reflection sidebands on the...

Université de Neuchâtel

Ferrocene-Containing Optically Active Liquid-Crystalline Side-Chain Polysiloxanes with Planar Chirality

Brettar, Julie ; Bürgi, Thomas ; Donnio, Bertrand ; Guillon, Daniel ; Klappert, Rolf ; Scharf, Toral ; Deschenaux, Robert

In: Advanced Functional Materials, 2005, vol. 16, p. 260 - 267

Optically active liquid-crystalline side-chain polysiloxanes have been prepared by grafting planar chiral ferrocene-based vinyl monomers onto commercially available polyhydrosiloxane. Two ferrocene monomers have been synthesized: a linear-type monomer, which displays a monotropic chiral smectic C (SC*) phase and enantiotropic smectic A (SA) and chiral N (N*) phases, and a laterally...