Dow Corning Corporation

Cambridge Enterprise Limited

Johnson Matthey Inc.

Merck Patent Gmbh

Harry J Coles

Jonathan Hannington

Mykhaylo Pivnenko

Damian Gardiner

Stephen Morris

William Alden Crossland

Martin Grasmann

Terry Clapp

Fumito Nishida

Anthony Bernard Davey

Huan Xu

David R Thomas

Omar Farooq

Wen-Kai Hsiao

Oliver Hadeler

Philip Hands

Timothy Wilkinson

Jonathon P Hannington

Ian Hutchings

Louise Diane Farrand

Russell Keith King

Russel Keith King

Mikhail N Pivnenko

Yong-il Cho

Marcus J Coles

Benjamin J Broughton

Damian J Gardiner

A method of manufacturing a security feature for identifying objects or documents of value. The method may include the steps of encoding information in a pattern; and ink jet printing a chiral nematic liquid crystal material from a reservoir using a print head on to a substrate in the pattern. Thus, the method forms a patterned array of chiral nematic liquid crystal material deposits. The print head, or the reservoir, or both, may be heated to a temperature above the clearing point of the chiral nematic liquid crystal material. The chiral axes of the chiral nematic liquid crystal material deposits may be aligned substantially perpendicular to the substrate such that a predetermined portion of the electromagnetic spectrum is selectively reflected over other regions of the electromagnetic spectrum by the chiral nematic liquid crystal material deposits.

Printing of liquid crystal droplet laser resonators on a wet polymer solution and product made therewith

A photonic device is manufactured by: (i) providing (e.g. by inkjet printing) an aliquot of a liquid crystal (LC) material; and (ii) depositing the aliquot onto the surface of a flowable material layer to form a liquid crystal deposit, the flowable material and the LC material being substantially immiscible. The liquid crystal deposit adopts a deformed shape relative to the shape of the aliquot due to interaction with the flowable material layer. This promotes alignment of the LC material. Incorporation of a laser dye allows the photonic device to function as a laser, which can be operated above or below threshold depending on the circumstances. The photonic device can also be used as a passive device based on the photonic bandgap of the aligned LC material.

A method of making a wide temperature-range smectic liquid crystal material comprises taking a wide temperature-range nematic mixture and doping this with a mesogenic silicon-containing material. Aspects of the invention provide wide temperature-range smectic materials and devices using the smectic materials.

Wide temperature-range smectic liquid crystal materials

A liquid crystal formulation is described. The liquid crystal formulation comprises a first oligosiloxane-modified nano-phase segregating liquid crystalline material; and at least one additional material selected from a second oligosiloxane-modified nano-phase segregating liquid crystalline material, non-liquid crystalline oligosiloxane-modified materials, organic liquid crystalline materials, or non-liquid crystalline materials, wherein the liquid crystal formulation has an I&#x2192;SmA*&#x2192;SmC* phase transition, with a SmC* temperature range from about 15&#xb0; C. to about 35&#xb0; C., a tilt angle of about 22.5&#xb0;&#xb1;6&#xb0; or about 45&#xb0;&#xb1;6&#xb0;, a spontaneous polarization of less than about 50 nC/cm2., and a rotational viscosity of less than about 600 cP. Devices containing liquid crystal formulations are also described. The device has a stable bookshelf geometry, bistable switching, and isothermal electric field alignment, a response time of less than 500 &#x3bc;s when switched between two stable states, and an electric drive field of less than about 30 V/&#x3bc;m.

Oligosiloxane modified liquid crystal formulations and devices using same

The instant invention relates to liquid crystal media comprising one or more bimesogenic compounds, one or more chiral dopants and one or more additives, liquid crystal displays comprising these media, in particular displays exploiting the flexoelectric effect and to a method of improving the response time of such displays.

Liquid crystalline medium and liquid crystal display

A liquid crystal formulation is described. The liquid crystal formulation comprises a first oligosiloxane-modified nano-phase segregating liquid crystalline material; and at least one additional material selected from a second oligosiloxane-modified nano-phase segregating liquid crystalline material, non-liquid crystalline oligosiloxane-modified materials, organic liquid crystalline materials, or organic non-liquid crystalline materials, wherein the liquid crystal formulation is nano-phase segregated in the SmC* phase, has an I&#x2192;SmC* phase transition, with a SmC* temperature range from about 15&#xb0; C. to about 35&#xb0; C., has a tilt angle of about 22.5&#xb0;&#xb1;6&#xb0; or about 45&#xb0;&#xb1;6&#xb0;, and has a spontaneous polarization of less than about 50 nC/cm2, and a rotational viscosity of less than about 600 cP. Devices containing liquid crystal formulations are also described. The device has a stable bookshelf geometry, bistable switching, and isothermal electric field alignment, a response time of less than 500 &#x3bc;s when switched between two stable states, and an electric drive field of less than about 30 V/&#x3bc;m.

A device for controlling the polarization state of transmitted light comprises first and second cell walls enclosing a layer of a chiral liquid crystal material. The material has a uniformly orientated helical axis in the absence of an applied field, and electrodes for applying an electric field substantially normal to the helical axis. An applied electric field flexoelectrically couples to the molecules, causing distortion of the helical structure and hence changes the bulk birefringence of the cell.

Flexoelectro-optic liquid crystal device

A blue phase liquid crystalline material comprising a mixture comprising at least one bimesogenic compound and at least one chiral compound, wherein the material is capable of stable existence in the blue phase over a temperature range of at least 5&#xb0; C. A process for the preparation of the above blue phase liquid crystalline material, an optical device comprising it, a process of mirrorless lasing and a slotted monolithic optical waveguide using it are also disclosed.

Liquid crystal materials

Siloxane compounds having a smectic liquid crystal phase and the general formula ##STR1## wherein each R=alkyl, alkenyl or aryl, Q represents a monovalent group, for example alkyl, --(CH.sub.2).sub.n OM', a chiral organic group, a dye group, a non-linear optic group or the group --(CH.sub.2).sub.n L, in which L represents a siloxane group, M and M' each represent ##STR2## wherein A is carboxyl, T is CN, F or Cl and p=0 or 1, provided that when T is F or Cl x has a value of at least 2.

Liquid crystal siloxanes

A liquid crystal device wherein the liquid crystal material is a siloxane-containing compound characterised by the the general formula ##STR1## wherein R is a C.sub.1-10 alkyl or ##STR2## each R' is a C.sub.1-4 alkyl, T is ##STR3## X is an alkyl or halogen-substituted alkyl group having at least one chiral center, Y is F, m is 0, 1 or 2 and n is 10, 11 or 12. Also claimed is a device wherein the liquid crystal material is disposed between a pair of substrates.

Liquid crystal devices

A liquid crystal device wherein the liquid crystal material exhibits a smectic phase and cromprises at least one siloxane compound having the general formula ##STR1## in which R=alkyl, alkenyl or aryl, Q represents a monovalent group, for example alkyl --(CH.sub.2).sub.n OM', a chiral organic group, a dye group, a non-linear optic group or the group --(CH.sub.2).sub.n L in which L represents a siloxane group, M and M' each represent ##STR2## wherein A is carboxyl, T is CN, F or Cl and p=0 or 1, provided that when T is F or Cl x has a value of at least 2.

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Stockport, United Kingdom

Harry J Coles