Zbd Displays Limited

Qinetiq Limited

Hewlett-packard Development Company, L.p.

Emma Louise Wood

Guy Peter Bryan-Brown

Ian Charles Sage

John Clifford Jones

William James Feast

Richard John Peace

Victor Chaklam Hui

Richard M Amos

Carl Vernon Brown

Stephen J Till

Philip T Worthing

A photopolymer mixture is capable of use for a liquid crystal alignment layer. An alignment layer is formed from such a photopolymer mixture. The mixture comprises at least two polymerisable materials which are blended together in proportion so as to give a predetermined, preferably low, surface energy. A low surface energy, e.g., less than 4&#xd7;10N/m, can result in an alignment layer which imparts a particular orientation to liquid crystal molecules with out requiring any post-cure treatments. The polymerisable materials may be monomers, oligomers, or diluents that form long chain molecules when cured, and the mixture may contain additives to lower the overall surface energy.

Liquid crystal alignment layer

A method and apparatus for forming a patterned layer having a surface profile that provides relief structures within an electronic device. The method comprises the steps of taking a carrier film () having an inverse of the required surface profile formed on one side thereof, taking a layer of fixable material () located on a substrate (), laminating the carrier film () and substrate () such the carrier film causes the required surface profile to be formed in the layer of fixable material with a predetermined offset, and then fixing the fixable material. Lamination may be performed using rollers () or a vacuum process. The process is designed to ensure that the offset can be kept as low as possible, preferably to within 150 nm.

Embossing method and apparatus

A repeated pattern layer having areas for imparting different electro-optic characteristics to a light modulating device is disclosed. The repeated pattern is arranged so that any pixel area formed in the assembled device (above a certain minimum size) will contain an area of each electo-optic characteristic in the right proportions. The pattern is arranged as a two dimensional grid of areas of different characteristic with at least one area of each characteristic provided in each row and column of the grid. The patterned layer may usefully be an alignment layer for a liquid crystal device, especially a bistable device, and the different areas may be arranged to give grey scale in the device.

Patterned light modulating device

Liquid crystal devices are described that exhibit bistable, tri-stable or other multistable operation. The stable liquid crystal configurations are attained using a surface alignment grating () on the internal surface of at least one cell wall (). The surface profile of the surface alignment grating comprises three or more defect sites per grating period and permit the liquid crystal molecules to adopt any one of two or more stable pretilt angles in the same azimuthal plane. Application of a suitable voltage causes the liquid crystal material to switch between the stable configurations.

Liquid crystal device

Organic light emitting diode devices having a substrate bearing an organic layer sandwiched between electrode structures. The organic layer includes, in a single layer a hole transporter, an electron transporter and a light emitter where the electron transporter or the light emitter or the electron transporter and the light emitter include a material of general formula 1.

Organic light emitting material and device

Liquid crystal devices are formed by a layer of a liquid crystal material enclosed between two cell walls, both carrying electrode structures, and one or both walls treated to align molecules of the liquid crystal material. Most alignment treatment give alignment and surface pretilt with a strong azimuthal and zenithal anchoring energy to contacting liquid crystal molecules. The invention reduces at least one of the azimuthal zenithal or translational anchoring energy to improve switching characteristics and optical performance by allowing movement of liquid crystal molecules at or close to the cell wall. The reduction of anchoring energy may be achieved by an oligomer or short chain polymer which is either spread on the surface or added to the liquid crystal material. The size of oligomer or short chain polymer is low enough that it does not appreciably phase separate from the liquid crystal material. The polymer layer has the characteristics of having imperfect solubility in the liquid crystal material used in the device, of having a physical affinity for the surface of the substrate, and of retaining a substantially liquid like surface at the polymer/liquid crystal interface. The polymer may be formed by polymerisation of reactive low molecular weight materials in solution in the liquid crystal fluid. The resulting solution or dispersion of polymer in liquid crystal is then filled into the cell, and the polymer is allowed to coat the substrate surfaces.

Liquid crystal device alignment

A first layer of photoresist material, sensitive to radiation of a first wavelength, has a second layer of photoresist material, sensitive to radiation of a second wavelength, deposited thereon. A pattern of radiation of the second wavelength is then formed on the second layer of photoresist material which is subsequently treated with a solvent, in which the first layer of photoresist material is insoluble, to develop a first periodic profile. The first layer of photoresist material is then exposed to radiation of the first wavelength through the first periodic profile and treated to develop a second periodic profile. By directing the radiation of the second wavelength through the first periodic profile at an angle to normal to the first material photoresist material a blaze profile may be obtained.

Process for making a periodic profile

This invention relates to an organic semiconductor device comprising a substrate bearing an organic layer sandwiched between electrode structures wherein the organic layer comprises a polymer of general Formula (I): wherein X is selected from H, CN, F, Cl, Br, COOCH . Y is given by the following general Formula (II): wherein A is a phenyl group which may be further substituted in 1 or 2 or 3 positions with groups independently selected from C alkyl, CN, F, Cl; B and C are both phenyl groups which may be further substituted, independently of each other, in 1 or 2 or 3 or 4 or 5 positions with groups independently selected from C alkyl, CN, F, Cl; A, B and C may also be, independently of each other, selected from pyrimidine, pyridazine and pyridine; m&equals;5-20,000.

Conducting polymers

This invention relates to statistical copolymers of general formula (I) and their use in organic semiconductor devices: wherein m and j are the average number of repeat units of A and B such that: m&equals;0.1-0.9, j&equals;1&minus;m, Q&equals;10-50000; A and B are independently selected from hole transporting groups and electron transporting groups and are statistically distributed along the polymer chain; X and Z are selected from H, CN, F, Cl, Br, CO CH .

Organic semiconductors based on statistical copolymers

A liquid crystal device comprises a cell ( ) formed by a layer ( ) of nematic or long pitch cholesteric liquid crystal material contained between two cell walls ( ). One wall ( ) carries a surface treatment giving a first azimuthal alignment direction with or without a surface pretilt to liquid crystal molecules. The other wall ( ) carries a surface treatment capable of separately providing both a preferred, substantially homeotropic alignment of the adjacent liquid crystal, and a defined azimuthal second alignment direction to the adjacent liquid crystal dependant upon liquid crystal molecular arrangement. The first and second alignment directions are approximately orthogonal. Polarisers ( ) may be arranged on either side of the cells walls with their polarization axes parallel or perpendicular to the two azimuthal directions. In addition one or more birefringent compensator layers ( ) are disposed on one side or on both sides of the cell ( ). The compensator layers ( ) may be formed of aligned polymer layers, or aligned liquid crystal material, either in a liquid form in a cell, or dispersed in a polymer sheet, or sheets of quartz or calcite slices. The device operates between two different voltage levels, one level (V ) providing a non twisted liquid crystal molecular arrangement, the other and higher voltage (V ) providing a twisted molecular arrangement.

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Malvern, United Kingdom

Emma Louise Wood