Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, 2001
Homopolysiloxanes poly(1) and poly(2) and copolysiloxanes poly(1-co-3) were synthesized. Their me... more Homopolysiloxanes poly(1) and poly(2) and copolysiloxanes poly(1-co-3) were synthesized. Their mesophase structures were investigated by X-ray diffraction, and the electron density profiles along the layer normal were derived. A linear response with the applied electric field was detected in the chiral smectic (C* or A*) phases of poly(1) and poly(2).
To reduce or completely remove the viewing angle dependence of liquid crystal displays and device... more To reduce or completely remove the viewing angle dependence of liquid crystal displays and devices, we have recently introduced a new electrode structure for liquid crystal displays. This electrode structure has openings (holes) in the pixel electrode for generating fringe electric field with the azimuthal degenerated distribution of the field lines around each hole, resembling a fountain. Such a field is promoting azimuthally degenerated switching of the liquid crystal molecules and thus generation of images with 360° viewing angle constant contrast when a pair of crossed circular polarisers are used. A theoretical model of the fountain fringe field, generated around a single circular hole and plurality of such holes in the pixel electrode, is presented.
Solid-state multi-focal and volumetric technologies highlight the future of 3D-display developmen... more Solid-state multi-focal and volumetric technologies highlight the future of 3D-display development. One of the most convenient implementations of multi-focal 3D displays are stacks of transparent liquid crystal displays. In this work, the core element is dissected—a switching optical diffuser element based on cholesteric liquid crystals, playing the role of a transparent display. In the present study, high-speed synchronized optical spectroscopy is used. We analyzed the kinetic and electro-optical characteristics of the diffuser element, the operation of which is based on the switching between diffuse and transparent states of this element. The underlying aim of this study was to investigate ways to improve some of these characteristics. It has been found that the transient peak in the optical transmission during field-off state, which is reducing the intensity of the light scattered by the diffuser element, is likely not associated to the assumed formation of the transient planar s...
L'invention concerne un dispositif electro-optique (2), des procedes de production correspond... more L'invention concerne un dispositif electro-optique (2), des procedes de production correspondants et un materiau a cristaux liquides (12) intercale entre des verres plats ou des substrats polymeres (4, 20) utilises comme electrodes et prealablement recouverts, par exemple, d'une couche superficielle chirale smectique (10, 14) de telle facon que cette couche superficielle puisse retransmettre la commutation des cristaux liquides (12) entre differents etats optiques. La couche superficielle chirale smectique peut etre un cristal liquide polymere, un oligomere ou monomere avec reponse paraelectrique, ferroelectrique, ferri-electrique ou antiferro electrique, qui est insoluble dans le cristal liquide utilise pour le substrat (12) qui est place entre les substrats (4, 20) servant d'electrodes. L'element directeur superficiel commutable fait executer une certaine orientation de l'axe optique dans le substrat a cristaux liquides (12) qui peut etre une matiere non-chiral...
Liquid crystals are organic materials constituting of molecules characterized by strong shape ani... more Liquid crystals are organic materials constituting of molecules characterized by strong shape anisotropy. Many studies unambiguously showed that some important physical effects observed in liquid crystals are strongly dependent on the shape anisotropy of their molecules. In this talk, some of the molecular shape related effects in liquid crystals, which have a potential for applications in liquid crystal displays (LCDs) and photonic devices, was overviewed. Photo-induced alignment transition from planar to vertical, flexoelectric polarization in short pitch cholesteric liquid crystals, alignment of bent core nematics as well as field driven transition from birefringent to optically isotropic state in these materials are among those effects on which this talk was focused. The role of the molecular shape was discussed with focus on the impact, which it has on the anchoring, flexoelectric, optical and electro-optical properties of the liquid crystals.
ABSTRACT The dependence of the dynamic behaviour of the smectic C* layer reorientation on applica... more ABSTRACT The dependence of the dynamic behaviour of the smectic C* layer reorientation on application of asymmetric electric fields is investigated for different surface treatment of the glass substrates, varying the alignment layer materials and rubbing conditions. It is found that already weak monostable anchoring limits the layer reorientation to twice the amount of the molecular tilt angle, while degenerate planar alignment promotes a continuous, unlimited rotation. Different layer reorientation times are observed for different alignment layer materials and can be correlated to the anchoring strength. Stronger anchoring hinders the reorientation of smectic layers. The number of buffing cycles (rubbing strength) does not have the expected pronounced effect on the layer reorientation, although increasing layer reorientation times are observed for increasing number of alignment layer rubbing cycles.
Reorientations of molecules in orthogonal smectic phases (SmA, SmB, and SmE) of a homologous seri... more Reorientations of molecules in orthogonal smectic phases (SmA, SmB, and SmE) of a homologous series of stilbenes have been studied by broad band dielectric spectroscopy and their activation energies have been determined. The effect of the molecular length on the reorientation around a short and the long molecular axis is described in detail. The reorientation around the long molecular axis
The invention relates to a liq. crystal device comprising a liq. crystal bulk layer and a surface... more The invention relates to a liq. crystal device comprising a liq. crystal bulk layer and a surface-director alignment layer comprising side-chains arranged to interact with the bulk layer, wherein the orientation of the bulk layer mols. and the orientation of said side-chains each is directly controllable by an elec. field via dielec. coupling, thus resulting in a decreased total time period (rise and decay times) needed to switch and relax the liq. crystal bulk mols. in response to an applied external field. The invention also relates to a method for manufg. a liq. crystal device and a method of controlling a liq. crystal bulk layer. [on SciFinder (R)] Notes: Can 142:82519 74-13 FIELD Section Title:Radiation Chemistry, Photochemistry, and Photographic and Other Reprographic Processes Field url: Ae, ag, al, am, at, au, az, ba, bb, bg, br, bw, by, bz, ca, ch, cn, co, cr, cu, cz, de, dk, dm, dz, ec, ee, eg, es, fi, gb, gd, ge, gh, gm, hr, hu, id, il, in, is, jp, ke, kg, kp, kr, kz, lc, lk, lr, ls, lt, lu, lv, ma, md, mg, mk, mn, mw, mx, mz, na, ni, no, nz, om, pg, ph, pl, pt, ro, ru, sc, sd, se, sg, sk, sl, sy, tj, tm, tn, tr, tt, tz, ua, ug, us, uz, vc, vn, yu, za, zm, zw. At, be, ch, cy, de, dk, es, fi, fr, gb, gr, ie, it, lu, mc, nl, pt, se, tr, bf, bj, cf, cg, ci, cm, ga, ml, mr, ne, sn, td, tg. G02f001-1337. C09k019-02. Application: WO 20040607. 2004-se880 Se 2003-1810 20030623 FIELD Citations:Mazaki, H; US 5578243 A 1996|Sharp Kk; GB 2326245 A 1998|Sharp Laboratories Of Europe Ltd; WO 0123953 A1 2001|Merck Patent Gmbh; EP 1310541 A2 2003 Secondary title: PCT Int. Appl.
An electro-optic device includes a liquid crystal cell (10, 10') and at least one electrode (... more An electro-optic device includes a liquid crystal cell (10, 10') and at least one electrode (40, 42, 40', 42') arranged to selectively electrically bias the liquid crystal cell (10, 10'). A chiral or cholesteric liquid crystal (30, 30') is disposed in the liquid crystal cell (10,10'). The liquid crystal (10,10') has an optic axis substantially along a selected optic axis direction in the absence of an electrical bias. A polymeric network (32, 32', 72) is disposed at an inside surface of the liquid crystal cell (10, 10'). The polymeric network (32, 32', 72) extends partway into the liquid crystal cell (10, 10') leaving at least a portion of the liquid crystal cell (10, 10') substantially free of the polymeric network (32, 32', 72). ® KIPO & WIPO 2007
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, 2001
Homopolysiloxanes poly(1) and poly(2) and copolysiloxanes poly(1-co-3) were synthesized. Their me... more Homopolysiloxanes poly(1) and poly(2) and copolysiloxanes poly(1-co-3) were synthesized. Their mesophase structures were investigated by X-ray diffraction, and the electron density profiles along the layer normal were derived. A linear response with the applied electric field was detected in the chiral smectic (C* or A*) phases of poly(1) and poly(2).
To reduce or completely remove the viewing angle dependence of liquid crystal displays and device... more To reduce or completely remove the viewing angle dependence of liquid crystal displays and devices, we have recently introduced a new electrode structure for liquid crystal displays. This electrode structure has openings (holes) in the pixel electrode for generating fringe electric field with the azimuthal degenerated distribution of the field lines around each hole, resembling a fountain. Such a field is promoting azimuthally degenerated switching of the liquid crystal molecules and thus generation of images with 360° viewing angle constant contrast when a pair of crossed circular polarisers are used. A theoretical model of the fountain fringe field, generated around a single circular hole and plurality of such holes in the pixel electrode, is presented.
Solid-state multi-focal and volumetric technologies highlight the future of 3D-display developmen... more Solid-state multi-focal and volumetric technologies highlight the future of 3D-display development. One of the most convenient implementations of multi-focal 3D displays are stacks of transparent liquid crystal displays. In this work, the core element is dissected—a switching optical diffuser element based on cholesteric liquid crystals, playing the role of a transparent display. In the present study, high-speed synchronized optical spectroscopy is used. We analyzed the kinetic and electro-optical characteristics of the diffuser element, the operation of which is based on the switching between diffuse and transparent states of this element. The underlying aim of this study was to investigate ways to improve some of these characteristics. It has been found that the transient peak in the optical transmission during field-off state, which is reducing the intensity of the light scattered by the diffuser element, is likely not associated to the assumed formation of the transient planar s...
L'invention concerne un dispositif electro-optique (2), des procedes de production correspond... more L'invention concerne un dispositif electro-optique (2), des procedes de production correspondants et un materiau a cristaux liquides (12) intercale entre des verres plats ou des substrats polymeres (4, 20) utilises comme electrodes et prealablement recouverts, par exemple, d'une couche superficielle chirale smectique (10, 14) de telle facon que cette couche superficielle puisse retransmettre la commutation des cristaux liquides (12) entre differents etats optiques. La couche superficielle chirale smectique peut etre un cristal liquide polymere, un oligomere ou monomere avec reponse paraelectrique, ferroelectrique, ferri-electrique ou antiferro electrique, qui est insoluble dans le cristal liquide utilise pour le substrat (12) qui est place entre les substrats (4, 20) servant d'electrodes. L'element directeur superficiel commutable fait executer une certaine orientation de l'axe optique dans le substrat a cristaux liquides (12) qui peut etre une matiere non-chiral...
Liquid crystals are organic materials constituting of molecules characterized by strong shape ani... more Liquid crystals are organic materials constituting of molecules characterized by strong shape anisotropy. Many studies unambiguously showed that some important physical effects observed in liquid crystals are strongly dependent on the shape anisotropy of their molecules. In this talk, some of the molecular shape related effects in liquid crystals, which have a potential for applications in liquid crystal displays (LCDs) and photonic devices, was overviewed. Photo-induced alignment transition from planar to vertical, flexoelectric polarization in short pitch cholesteric liquid crystals, alignment of bent core nematics as well as field driven transition from birefringent to optically isotropic state in these materials are among those effects on which this talk was focused. The role of the molecular shape was discussed with focus on the impact, which it has on the anchoring, flexoelectric, optical and electro-optical properties of the liquid crystals.
ABSTRACT The dependence of the dynamic behaviour of the smectic C* layer reorientation on applica... more ABSTRACT The dependence of the dynamic behaviour of the smectic C* layer reorientation on application of asymmetric electric fields is investigated for different surface treatment of the glass substrates, varying the alignment layer materials and rubbing conditions. It is found that already weak monostable anchoring limits the layer reorientation to twice the amount of the molecular tilt angle, while degenerate planar alignment promotes a continuous, unlimited rotation. Different layer reorientation times are observed for different alignment layer materials and can be correlated to the anchoring strength. Stronger anchoring hinders the reorientation of smectic layers. The number of buffing cycles (rubbing strength) does not have the expected pronounced effect on the layer reorientation, although increasing layer reorientation times are observed for increasing number of alignment layer rubbing cycles.
Reorientations of molecules in orthogonal smectic phases (SmA, SmB, and SmE) of a homologous seri... more Reorientations of molecules in orthogonal smectic phases (SmA, SmB, and SmE) of a homologous series of stilbenes have been studied by broad band dielectric spectroscopy and their activation energies have been determined. The effect of the molecular length on the reorientation around a short and the long molecular axis is described in detail. The reorientation around the long molecular axis
The invention relates to a liq. crystal device comprising a liq. crystal bulk layer and a surface... more The invention relates to a liq. crystal device comprising a liq. crystal bulk layer and a surface-director alignment layer comprising side-chains arranged to interact with the bulk layer, wherein the orientation of the bulk layer mols. and the orientation of said side-chains each is directly controllable by an elec. field via dielec. coupling, thus resulting in a decreased total time period (rise and decay times) needed to switch and relax the liq. crystal bulk mols. in response to an applied external field. The invention also relates to a method for manufg. a liq. crystal device and a method of controlling a liq. crystal bulk layer. [on SciFinder (R)] Notes: Can 142:82519 74-13 FIELD Section Title:Radiation Chemistry, Photochemistry, and Photographic and Other Reprographic Processes Field url: Ae, ag, al, am, at, au, az, ba, bb, bg, br, bw, by, bz, ca, ch, cn, co, cr, cu, cz, de, dk, dm, dz, ec, ee, eg, es, fi, gb, gd, ge, gh, gm, hr, hu, id, il, in, is, jp, ke, kg, kp, kr, kz, lc, lk, lr, ls, lt, lu, lv, ma, md, mg, mk, mn, mw, mx, mz, na, ni, no, nz, om, pg, ph, pl, pt, ro, ru, sc, sd, se, sg, sk, sl, sy, tj, tm, tn, tr, tt, tz, ua, ug, us, uz, vc, vn, yu, za, zm, zw. At, be, ch, cy, de, dk, es, fi, fr, gb, gr, ie, it, lu, mc, nl, pt, se, tr, bf, bj, cf, cg, ci, cm, ga, ml, mr, ne, sn, td, tg. G02f001-1337. C09k019-02. Application: WO 20040607. 2004-se880 Se 2003-1810 20030623 FIELD Citations:Mazaki, H; US 5578243 A 1996|Sharp Kk; GB 2326245 A 1998|Sharp Laboratories Of Europe Ltd; WO 0123953 A1 2001|Merck Patent Gmbh; EP 1310541 A2 2003 Secondary title: PCT Int. Appl.
An electro-optic device includes a liquid crystal cell (10, 10') and at least one electrode (... more An electro-optic device includes a liquid crystal cell (10, 10') and at least one electrode (40, 42, 40', 42') arranged to selectively electrically bias the liquid crystal cell (10, 10'). A chiral or cholesteric liquid crystal (30, 30') is disposed in the liquid crystal cell (10,10'). The liquid crystal (10,10') has an optic axis substantially along a selected optic axis direction in the absence of an electrical bias. A polymeric network (32, 32', 72) is disposed at an inside surface of the liquid crystal cell (10, 10'). The polymeric network (32, 32', 72) extends partway into the liquid crystal cell (10, 10') leaving at least a portion of the liquid crystal cell (10, 10') substantially free of the polymeric network (32, 32', 72). ® KIPO & WIPO 2007
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