Optical rewritable liquid‐crystal‐alignment technology

Abstract

Abstract— A new optical rewritable (ORW) liquid‐crystal‐alignment technology has been developed to create a display and to demonstrate its maturity and potential. ORW displays have no electrodes and use polarizers as substrates. The display requires no photolithography on plastic. Its simple construction secures durability and low cost for mass production. The on‐screen information is optically changed in a writing unit that consists of an LCD mask and an exposure source that is based on LEDs, low power, and low cost in comparison with Hg lamps or lasers. A high contrast image can be easily written, viewed, and rewritten through a polarizer, while the multi‐stable gray‐level image requires zero power to maintain the image. Reconfigurable LC alignment using ORW technology best suits plastic‐card displays as well as for LC photonics and various one‐mask processes of patterned LC‐alignment applications.

Stabilization of liquid crystal photoaligning layers by reactive mesogens

“…On the contrary, LC alignment in the filled cells can be easily controlled by light of proper spectral composition. 4 The attempt to strengthen the photostability of diazodyes was made 5 where molecules of the dyes were tailed with the reactive groups capable to crosslink. However, this idea was found not very efficient because the attached terminal groups worsen the LC alignment.…”

Electric and magnetic fields in photoalignment of liquid crystals

“…2 Namely, it consists of two glass substrates with inner surfaces treated by different procedures. The first substrate was treated in accordance with traditional rubbing technique to provide planar orientation of LC along x-axis ( Fig.…”

“…Contrary, the pure rotation of the monodomain planar samples was observed at high strength of electric field. (1) and U = 7 V, t exp = 15 min for area (2). Arrows indicate position of polarizers, and n e (0) [n e (t)] shows initial (reoriented) direction of NLC easy axis at the substrates (Fig.…”

“…2 We performed the experiments with light irradiation at both wavelengths in the presence of the electric field.…”

“…Such property, in turn, provides the light-controlled changes of surface and bulk orientation of LC that were used to propose the original optical rewritable (ORW) technology. 2 The latter technology is interesting for different applications, like bistable displays, e-paper, fiber optics, and photonics devices. 3 Usage of additional factors such as electric field may provide optimization of technical characteristics of LC devices based on ORW technology.…”