Abstract: In a method of driving a matrix of ferroelectric liquid crystal devices in a TDM mode, each strobing signal comprises first and second pulses (20,21) of opposite polarities and of different amplitudes, together with a dc voltage (26) which is applied from the end of the second pulse to the beginning of the first pulse of the next strobing signal on the same strobe line to cancel the dc level which would be caused by the unequal pulses. Data ON signals applied selectively to data lines of the matrix comprise two consecutive pulses (22,23) of opposite polarities. Data OFF signals (24,25) may be the inverse of the data ON signals or may comprise a constant dc level. The combination of the two pulses with a dc level to form each strobing signal means that only two strobe pulse time slots per frame are required for addressing each strobe line, as compared with the conventional systems in which four time slots per frame are required.

Abstract: In a method of forming a matrix addressable display comprising a group of switchable cells, such as liquid crystal cells, having electrodes on each of two parallel plates and thin-film drive transistors disposed on one of the plates, gate resistors are provided by elongate doped polysilicon regions connecting the gate electrodes to address lines. The gate resistors prevent short-circuiting of the address lines in the event of a gate short-circuit occurring in any of the transistors.

Abstract: Liquid crystal polymers, which may be used for optical information storage, either alone or in mixture with other liquid crystals, are of the general formula ##STR1## wherein the mesogenic grouping M has a general structure ##STR2## wherein the rings P and Q are selected from phenyl, trans-cyclohexyl, pyridyl, pyrimidinyl, dioxanyl, and bicyclo (2.2.2) octyl. The rings P and/or Q may carry lateral substituents, preferably Me or F. The general structure of Formula (I) may represent a homopolymer or a copolymer.

Abstract: A device for detecting the presence of a chemical material, such as a gas, amongst a number of incident chemical materials comprises a group of sensors having overlapping broadband selectivities in respect of the incident materials, so that each sensor responds, to a greater or smaller extent, to each of the materials. The sensor outputs are fed to a signal processor which produces, for each material, a notional vector. These vectors are compared with stored reference vectors to identify the material under investigation. The responses to the various materials have a time-varying portion and a portion of constant value. Certain materials may produce the same constant value, but different time-varying portions. The latter portions are therefore also taken into account in identifying the materials. A chromatographic layer may be provided over the sensors to distinguish between chemical species in the materials under test.

Abstract: A radio receiver antenna arrangement incorporating an RF pre-amplifier (5) wherein circuitry (11 to 21) is provided for by-passing the pre-amplifier when strong signals are picked up by the antenna (1) to avoid overloading the pre-amplifier.

Abstract: The invention provides a polymer comprising a chain of detectable units joined together by linker arms.The detectable units may be, for example, antigenic or form part of a fluorescent or chemiluminescent or chromogenic or enzyme signal system.The polymer may find an application in the assay of an analyte which is a member of a specific binding pair.The invention also provides a labelled reagent in which the reagent is a member of a specific binding pair and the label is a polymer in accordance with the invention. The invention further provides an assay involving the use of a labelled reagent in accordance with the invention. Also the invention provides a kit for performing an assay, which kit includes a supply of a labelled reagent in accordance with the invention.

Abstract: A method of determining the proportions of different components of material in a duct comprises exciting nuclear magnetic spins of nuclei of a species common to the components in a region of the duct and utilizing the resulting free induction decay (FID) signal. The nuclear spins are excited simultaneously in the components and the proportions are determined by measuring the phase of the FID signal relative to a phase datum. The method finds particular application for measuring the proportions of oil and water in material obtained from a sub-sea oil well.

Abstract: A radio receiver system for receiving double sideband signals from a plurality of antennas (N1,N2) having different reception characteristics detects a reduction in power in one of the sidebands of a received signal, due to multiple path reception or other disturbances. The system then selects for use by the receiver a signal from an antenna less affected by the disturbances.

Abstract: A sensor device for the analysis of a sample fluid comprises a substrate in a surface of which an elongate channel is micromachined. The channel contains a material, such as a starch, agarose, alginate, carrageenin or polyacrylic polymer gel, with a biological material for causing separation of the sample fluid as the fluid passes along the channel. The biological material may comprise, for example, a binding protein, an antibody, a lectin, an enzyme, a sequence of enzymes or a lipid. Pairs of sensing electrodes are spaced apart along the walls of the channel. The device may be used, for example, for testing blood samples.

Abstract: A radio telemetry system for collecting the readings of consumer's electricity consumption meters includes a master station (1) carried by a vehicle (1) and a plurality of transponders (3), each of which holds an electrical quantity indicative of an amount of electrical power consumed as measured by the meter associated with that transponder (3). The transponders (3) and the master station (1) communicate such that the transponders (3) transmit to the master station (1) signals containing information as to the values of the aforesaid electrical quantities held by them. Such communication takes place on a relatively quiet channel, of a number of channels, as determined by the master station (1) such that the system is capable of operating satisfactorily when the master station (1) and the transponders (3) utilise relatively low power transmitters (7, 19).

Abstract: A radio receiver antenna system including an antenna arrangement (1) which provides two signals (v.sub.a, v.sub.b) respectively as are provided by two antennas having different reception characteristics, and circuitry (T1, T2, 35 to 47) for combining the signals so that the output (V.sub.0) is significant for all values of the relative phase of the two signals. A particular application is in vehicle radio receiver systems using the rear window heater as an antenna.

Abstract: In a process for depositing a planarising material in spaces between a pattern of regions, such as dye stripes or dots, on a substrate, the planarising material is deposited as a layer over the pattern. The substrate is irradiated, from the reverse side, by a source of radiation, such as UV, to which the pattern material is opaque and to which the planarising material is responsive such that it is rendered insoluble to a particular solvent. The radiation acts on only those parts of the planarising material which are in the spaces. The remainder of the planarising layer is then removed by use of the solvent. Alternatively, or additionally, an ITO or other UV transparent layer may be formed over the pattern and a layer of resist formed thereover. The radiation then passes through the spaces and acts on only the resist areas over the spaces to render them soluble. Those areas and the ITO layer beneath them are then removed by etching, leaving ITO areas accurately aligned with the pattern.

Abstract: A radio receiver antenna system for overcoming multiple path propagation fading, includes an antenna arrangement which provides respectively at two terminals in response to a given transmitted signal, two signals at the frequency of the transmitted signal as are respectively produced by two antennas having different reception characteristics. A combining circuit is operative for producing an output at the frequency of the transmitted signal by combining the signals produced at said terminals in such manner that the output is significant for substantially all values of the relative phase of the two signals. The combining circuit includes an inductive winding to opposite ends of which the two signals are respectively applied. An output is derived from a tapping point on the winding or from a second winding, inductively coupled to said first-mentioned winding. A first output is preferably derived from a tapping point on the first-mentioned winding.

Abstract: A laser source for pumping an optical device which requires for its operation a significant amount of light power, the source comprising a semiconductor array (11) for providing a plurality of spaced apart light beams at different wavelengths, an optical assembly (14, 15, 16) for focussing the light beams into an optical waveguide (19), the optical waveguide (19) being coupled to the optical device.

Abstract: An updatable optical storage device, which may be in microfiche configuration, includes two electrically conductive layers (2,6) between which a layer (5) of a liquid crystal storage material and a layer (3) of a photoconductive material are sandwiched. In order to record an image on the device, the image is projected on to the photoconductive layer through one of the conductive layers, a voltage is applied between the conductive layers, and the storage material is heated at least over regions where the image is to be stored. Projection of the image is continued until the storage material has cooled. The storage material may, for example, be a liquid crystal polymer or a glassy nematic liquid crystal material. The process can be repeated any number of times to update any part or all of the iamge.

Abstract: A fluid dispenser for use, for example, in an ink jet printing head, comprises a switching device, preferably a bistable fluidic device, which switches fluid under pressure between a path in which the fluid circulates back to the fluid source and a second path in which it issues from a jet. The fluidic device is preferably formed by micro-machining cavities in a silicon substrate, or in two substrates which are then bonded together face to face. A printing head may be formed by locating a number of the dispensers in side-by-side relation with spacers therebetween, the spacers being used to provide feed paths for the ink.

Abstract: In the production of micron-size pyramid emitters for field emission devices, a first layer of electrically-conductive material, such as single crystal silicon or metal, is etched to form column-like structures each of which tapers from each end of the column towards an intermediate portion along its length. A second conductive layer is formed in contact with the free ends of the columns, and etching of the columns is then resumed until the intermediate portion of each column is etched through, leaving a pair of pyramid emitters pointing towards one another and supported by the respective conductive layer.

Abstract: An apparatus for depositing a thin film of amorphous or polycrystalline silicon on substrates by a low-pressure chemical vapor deposition process includes a high-speed pump device connected to one end of a vapor deposition chamber and operative to maintain in the vapor deposition chamber a pressure at or below 20 milliTorr, an inlet adjacent the other end of the chamber for introducing gas into the chamber such that the gas flows from the gas inlet toward the pump device, and a substrate support within the vapor deposition chamber for orientating the major faces of the substrates substantially perpendicularly to the gas flow direction, wherein the combined conductance of the vapor deposition chamber, substrate support, and substrates is at least ten times the conductance of the pump device.

Abstract: A klystron device comprises an array of cold-cathode field emission elements arranged to form a distributed amplifier which further comprises a modulation strip line and a catcher strip line. A collector electrode is spaced from the catcher strip line. The device may include a deflector for returning electrons emitted by the elements back to the modulation strip line so that the device acts as an oscillator.

Abstract: Data stored on a remotely-located storage sheet (29,30,31) which may, for example, be a sheet of a spare-parts manual used in the motor trade, can be updated by transmitting a signal from a central station (20) to a receiver (21,22,23) at the remote location. The storage sheet may be in the form of a microfiche. A liquid crystal storage device is used as the storage sheet, which device can be updated by light from a simple laser printer, an imaging array, or a CRT screen at the remote location, operated by the transmitted signal. This avoids the need to replace storage sheets when updating is necessary. The storage sheet may include two electrically conductive layers (2,6) between which are disposed a layer of a liquid crystal storage material (5) and a photoconductive layer (3). The liquid crystal material may be, for example, a liquid crystal polymer or a glassy nematic liquid crystal material.