Abstract: A liquid crystal device comprises a layer (2) of a nematic liquid crystal material contained between two cell walls (3, 4) each carrying electrode structures (6, 7) and an alignment surface (20, 21). The alignment layer (20, 21) on one or both cell wall (4), is formed of a plurality of small (<15 ?m) surface features each separably capable of providing a bistable pretilts and an alignment direction and collectively causing larger variations of molecular orientation across the layer (2). The device may be switched between a light transmissive state and a light non-transmissive state. The small surface features may be areas of grating (21), protrusions (25), or blind holes (26), separated by mono stable flat surfaces (Fm) coated with a homeotropic alignment layer. Preferably, the grating etc provides bistable switching operation between a low surface tilt and high surface tilt, and the low tilt alignment direction varies between adjacent grating areas.

Abstract: A liquid crystal device comprises a layer (2) of a nematic liquid crystal material contained between two cell walls (3, 4) each carrying electrode structures (6, 7) and an alignment surface (20, 21). The alignment layer (20, 21) on one or both cell wall (4), is formed of a plurality of small (<15 ?m) surface features each separably capable of providing a bistable pretilts and an alignment direction and collectively causing larger variations of molecular orientation across the layer (2). The device may be switched between a light transmissive state and a light non-transmissive state. The small surface features may be areas of grating (21), protrusions (25), or blind holes (26), separated by mono stable flat surfaces (Fm) coated with a homeotropic alignment layer. Preferably, the grating etc provides bistable switching operation between a low surface tilt and high surface tilt, and the low tilt alignment direction varies between adjacent grating areas.

Abstract: This invention relates to a photopolymer mixture capable of use for a liquid crystal alignment layer and to an alignment layer 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 4×10?2 N/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.

Abstract: This invention relates to a liquid crystal device with grey scale. The invention uses dither, either spatial or temporal. For spatial dither the invention arranges so that at least one bit of dither is not a multiple of the size of a smaller bit of dither—in other words there is a fractional weighting. The two bits of dither have the same number of addressable transmission levels and the weighting sacrifices some linearity in exchange for reduction of manufacturing tolerances for the smaller bit. For temporal dither the invention relates to fractional weighting of the duration of the sub-frames.

Abstract: A method of addressing bistable nematic liquid crystal devices is provided. The method is suitable for implementation using commercially available STN drivers. The method involves applying one of at least two data waveforms simultaneously to each column electrode whilst an active row waveform is applied to an active row and a non active row waveform is applied to all other rows. The resultant waveform at the pixels on the active row comprises a blanking portion sufficient to cause the liquid crystal material to blank, irrespective of which data waveform is applied, immediately followed by a discriminating portion which allows for selective latching depending on the data waveform applied.

Abstract: A method of addressing multistable nematic liquid crystal devices, in particular bistable nematic liquid crystal devices is provided. The method is a line at a time addressing scheme where one of at least two data waveforms is applied simultaneously to each of the column electrodes whilst a strobe waveform is applied to a row. The strobe waveform comprises a blanking portion sufficient to cause the liquid crystal material to blank, irrespective of which data waveform is applied, immediately followed by a discriminating portion which is such that in combination with an appropriate data waveform allows for selective latching. At least part of both the blanking portion and the discriminating portion are applied during the line address time for the particular row of interest.

Abstract: 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 (144) on the internal surface of at least one cell wall (142). 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.

Abstract: A liquid crystal device is provided that comprises a layer of liquid crystal material (2) disposed between two cell walls (4, 6) in an arrangement such that the liquid crystal material (2) can adopt any one of two or more stable liquid crystal configurations that will persist in the absence of an applied electric field. The liquid crystal device is operable in two modes; a first mode in which application of an appropriate latching voltage pulse can select any one of the two or more stable liquid crystal configurations, and a second mode in which application of an electric field can switch the layer of liquid crystal material from a latched configuration to a switched configuration and in which the layer of liquid crystal material will return to said latched configuration when the applied electric field is removed.

Abstract: A user identification capability for network environrnents. A user's identity is created using information provided by a user, as well as information provided by a third party, such as an internet service provider, a business, a service, an access device, etc. The identity is used to determine the context in which a user is accessing a process, such as a server, application, network entity, firewall, router, etc.

Abstract: 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 (144) on the internal surface of at least one cell wall (142). 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.

Abstract: A bistable nematic liquid crystal device is addressed by application of a row waveform to successive row electrodes of an x, y matrix of pixels whilst one of two data waveforms are applied to each column electrode. The row waveform has a period of two or more time slots (ts), with two dc pulses of opposite amplitude for causing a switching to a dark state, and two dc pulses of opposite amplitude for causing a switching to a light state. The data waveforms have the same period as the strobe with dc pulses of opposite amplitude and combine with the strobe pulses to switch the device. The device can be addressed in two field periods, one field switching to a dark state, the other field switching to a light state. Alternatively, the device can be blanked to the dark state then selectively switched to the light state. When blanking is used, the row waveform has blanking de pulses placed a short time before selective switching to reduce overall addressing time.

Abstract: 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.

Abstract: A liquid crystal device is provided that comprises a layer of liquid crystal material (2) disposed between two cell walls (4, 6) in an arrangement such that the liquid crystal material (2) can adopt any one of two or more stable liquid crystal configurations that will persist in the absence of an applied electric field. The liquid crystal device is operable in two modes; a first mode in which application of an appropriate latching voltage pulse can select any one of the two or more stable liquid crystal configurations, and a second mode in which application of an electric field can switch the layer of liquid crystal material from a latched configuration to a switched configuration and in which the layer of liquid crystal material will return to said latched configuration when the applied electric field is removed.

Abstract: An oxygen leakage regulator tester to test for air leaks in O2 supply equipment, such as oxygen masks and hoses used by flight personnel. The tester uses electromechanical sensors and a central processing unit, coupled to digital displays for accurate readouts.

Abstract: A method of addressing multistable nematic liquid crystal devices, in particular bistable nematic liquid crystal devices is provided. The method is a line at a time addressing scheme where one of at least two data waveforms is applied simultaneously to each of the column electrodes whilst a strobe waveform is applied to a row. The strobe waveform comprises a blanking portion sufficient to cause the liquid crystal material to blank, irrespective of which data waveform is applied, immediately followed by a discriminating portion which is such that in combination with an appropriate data waveform allows for selective latching. At least part of both the blanking portion and the discriminating portion are applied during the line address time for the particular row of interest.

Abstract: A surfacing method and apparatus produce a smooth surface on the wall of a swimming pool. The smooth surface minimizes both algae growth on the pool wall and skin abrasions caused by the surface. The method and apparatus utilize a cement slurry composition which includes a liquid bonding agent and fibers to increase the strength of the surface so the surface can be polished by a water cooled diamond impregnated surfacing wheel.

Abstract: A partitioned processing system is disclosed wherein a common security server is run in a first partition and at least one server client is run in at least one other partition, each partition having a shared memory or memory-to-memory connection to said first partition, which enables security client server communication with the common security server. The partitioned processing system additionally has a main storage having a first portion accessible by the first partition and a second portion accessible by the second partition. Also included is a mechanism connected to the security client for sending a request for authorization by a user to the security client. A first transmitter in the security client sends the request for authorization from the security client to the common security server by way of said main storage. A second transmitter in the common security server sends a response to the request for authorization from the common security server to the security client by way of said main storage.

Abstract: A liquid crystal composition includes a host material comprising (a) two or more phenylpyrimidinyl compounds of general formula (I), wherein X1 and X2 are independently selected from the group consisting of straight or branched chain (C1-C12)alkyl, straight or branched chain (C1-C12)alkenyl and straight or branched chain (C1-C12)alkoxy, in which either or both of the alkyl, alkenyl or alkoxy groups may be substituted by one or more of halogen, oxygen and siloxane, and (b) at least one fluoroterphenyl compound of formula (II) or (III), wherein Y1 et Y2 are independently selected from the group consisting of straight or branched chain (C1-C12)alkyl, straight or branched chain (C1-C12)alkenyl and straight or branched chain (C1-C12)alkoxy, and wherein either or both of the alkyl, alkenyl or alkoxy groups may be substituted by one or more of halogen, oxygen and siloxane.

Abstract: A liquid crystal device comprises a liquid crystal cell including a layer of ferroelectric smectic liquid crystal material contained between two walls bearing electrodes and surface treated to give both an alignment and a surface tilt to liquid crystal molecules. The material adopts a C2 rather than a C1 arrangement by arranging the surface pretilt &xgr; and the ratio of azimuthal to zenithal anchoring energies &bgr;/&agr; to give a positive energy difference &Dgr;Ws for the liquid crystal director at the surface in the C1 and C2 states. Additionally the provision of a C2 state may be enhanced by allowing the cell to cool from the isotropic phase to a temperature just below a smectic A to chiral smectic phase, then applying 50 Hz ac voltage in the range typically 0.1 to 5 volts rms. across the liquid crystal layer for about 90 seconds, then allowing the cell to cool to ambient temperature.

Abstract: A large area liquid crystal display comprises a layer of liquid crystal material between two cell walls. One cell wall has a common sheet electrode. The other cell walls comprise a plurality of addressing tiles electrically connected together. Driver circuits at the display edges apply addressing voltages. Each addressing tiles comprises a series of m data electrodes and n gate electrodes arranged to form an m×n matrix array of electrode intersections. At each intersection is a pixel patch electrode and a non linear element connected to adjacent source and gate electrodes and to the pixel electrode. The data and gate electrodes continue across the tile surface and around its edges. Adjacent tiles are electrically connected together by an anisotropic glue, or by solder bumps, or electrical bridges. The liquid crystal material may be encapsulated in a polymer matrix or be a non-encapsulated layer. Dyes may be incorporated in the liquid crystal material.