Liquid‐crystal photoaligning by azo dyes (Invited Paper)

Abstract

Abstract— Liquid‐crystal (LC) photoalignment using azo dyes is described. It will be shown that this photoaligning method can provide a highly uniform alignment with a controllable pretilt angle and strong anchoring energy of the LC cell, as well as a high thermal and UV stability. The application of LC photoalignment to the fabrication of various types of liquid‐crystal displays, such as VAN‐LCDs, FLCDs, TN‐LCDs, and microdisplays, on glass and plastic substrates is also discussed. Azo‐dye photoaligned super‐thin polarizers and phase retarders are considered as new optical elements in LCD production, in particular for transflective displays.

Photo-alignment of liquid crystals in micro capillaries with point-by-point irradiation

“…They both create a thin layer within a micro hole of the fibre before filling it with a LC [15][16]. The layer can be com− posed of: polymers, azo−dyes [17][18] or different LCs [19][20]. Once this process is completed, the sample is ex− posed to UV light (or in case of thermal alignment -to bak− ing in high temperature), which results in molecules' rearrangement.…”

Cooperative liquid-crystal alignment generated by overlaid topography

“…Current LC devices such as displays require specific and predictable LC alignment characteristics [1][2][3][4][5] and future LC applications, such as in organic photovoltaics (OPV), will depend on effective alignment of novel materials systems [6]. In the latter case, for example the discotic and polymeric composite systems under development can be difficult to orient in electrically efficient geometries, a problem complicated by the nanoheterogeneity required for efficient PV performance.…”

Latest Liquid Crystal Technology

“…However, Schadt continued the search for stable, non-cylinder symmetric photo-aligning polymers with his coworkers at Roche and later at Rolic even though the odds were against his conviction that optically stable photo-materials with non-cylinder symmetry are feasible. He was convinced that the demanding alignment stability and non-cylinder symmetry required for LCD alignment cannot be realized by the cis-trans azo mechanism pursued by most groups [46]. Four years later, the author [47] and coworkers discovered the first side-chain photopolymer material which combined non-cylinder symmetry and uniaxiality upon oblique polarized UV Fig.…”