Photo-Generation of Linearly Polymerized Liquid Crystal Aligning Layers Comprising Novel, Integrated Optically Patterned Retarders and Color Filters

Abstract

For the first time photo cross-linking of linearly polymerizable polymers (LPPs) is shown to induce uniaxial planar alignment in adjacent liquid crystal polymer (LCP)-layers on single substrates. Ways and novel materials allowing integration of LPP-aligning layers with optical retarders in patterned, hybrid LPP-LCP-configurations with freely adjustable optical axes are presented. The novel multifunctional, anisotropic photopolymer configurations are shown to render in-situ optical retarders and polarization interference filters for black-white and color liquid crystal displays (LCDs) feasible. The molecular mechanisms inducing the anisotropic film properties and their thermal and optical stabilities are outlined. The photo-patternable, high resolution hybrid configurations are shown to exhibit excellent thermal and light stability.

Modification of the twist angle in chiral nematic polymer films by photoisomerization of the chiral dopant

“…In that case, the gray scales have to be produced by changing the polarization direction of the light. 10 A complex pattern containing gray scales was recorded in the polymer film using a negative of a photograph. Compared to the patterns shown in Fig.…”

“…(E)-(1R,4R) -2 -͑4 -͑4 -hexyloxybenzoyloxy ͒phenyl -methene͒ menthan-3-on ͑NRM͒ and poly͓4͑6-acryloyloxyhexyloxy͒ benzoyloxy͒benzonitrile͔ ͑polyCN͒ were synthesized according to previously published procedures. 8,10 The melting point of NRM was 96°. The molecular weight (M n ) of polyCN was 6100 g/mol and the polydispersity was 1.…”

“…[1][2][3][4][5][6][7] More recently, much attention is given towards local control of the alignment of liquid crystals in multidomain liquid crystal displays for the improvement of the viewing angle. [8][9][10] In general, the liquid crystal ͑LC͒ orientation can be influenced via modification of the bulk LC orientation or, indirectly, via modification of the alignment layer. Modification of the transmission of liquid crystal layers between crossed polarizers via directly influencing the bulk orientation of liquid crystals has been shown to be possible using polarized light illumination of LC layers containing dyes.…”

Liquid crystal displays, LC-materials and LPP photo-alignment

“…The goal was to achieve optically perfect photo-patterned LCP thin-films with azimuthal and zenithal tunable optical anisotropy on single LPP-photo-aligned substrates. In the mid-1990s Schadt et al demonstrated and patented for the first time the feasibility of surface alignment and pattering of planar liquid crystal pre-polymer films on single substrates [54]. Apart from uniaxial planar LCP-alignment it was shown that the transfer of LPP-bias tilt into LCP-films was possible and also that stacking of different LCP-films with azimuthally different slow optical axes of index ellipsoids was feasible [55].…”

Ferroelectric Liquid Crystal Dammann Grating by Patterned Photoalignment

“…In this way, a customized LC director distribution can be achieved to offer special designed optical functions. Many photonic devices can be achieved via patterned alignment, including patterned retarders [9,10], Q-plates [4,5], LC gratings [11,12], LC lenses [13][14][15], and polarization converters [16][17][18], etc., which could find many important applications in beam shaping [4], imaging system [13,14], Complementary Metal Oxide Semiconductor (CMOS) sensor system [19] and 3D display [10], etc.…”