Abstract: A composite material having a force- or pressure-dependent resistance comprises particles of inorganic chalcogenide dispersed in a polymer. The chalcogenide may be a pyrite such as iron pyrite, copper iron pyrite or a mixture of the two. The composite material may be used in a force or pressure sensor, for example in a wearable device.

Abstract: A polymer composition comprises at least one substantially non-conductive polymer binder and at least first and second electrically conductive fillers. The first electrically conductive filler is comprised of particles having avoid-bearing structure; and the second electrically conductive filler is comprised of particles which are acicular in shape.

Abstract: An electrically responsive composite material is disclosed, along with a method of producing an electrically responsive composite material, a transducer having a substrate for supporting a flowable polymer liquid and a method of fabricating a transducer. The electrically responsive composite material produced is configurable for application in a transducer. The method includes the steps of receiving the flowable polymer liquid and introducing electrically conductive acicular particles (1501, 1502) to facilitate the conduction of electricity by quantum tunneling. Dielectric particles (1505, 1506) are added of a size relative to the acicular particles such that a plurality of these dielectric particles are dispersed between adjacent acicular particles.

Abstract: A polymer composition comprises at least one substantially non-conductive polymer binder and at least first and second electrically conductive fillers. The first electrically conductive filler is comprised of particles having avoid-bearing structure; and the second electrically conductive filler is comprised of particles which are acicular in shape.

Abstract: An electrically responsive composite material is disclosed, along with a method of producing an electrically responsive composite material, a transducer having a substrate for supporting a flowable polymer liquid and a method of fabricating a transducer. The electrically responsive composite material produced is configurable for application in a transducer. The method includes the steps of receiving the flowable polymer liquid and introducing electrically conductive acicular particles (1501, 1502) to facilitate the conduction of electricity by quantum tunneling. Dielectric particles (1505, 1506) are added of a size relative to the acicular particles such that a plurality of these dielectric particles are dispersed between adjacent acicular particles.

Abstract: A thermal detector device comprising an array of thermal detector elements, an array of microbridge structures comprising the array of thermal detector elements, readout silicon integrated circuitry (ROIC) and an interconnect layer on which the array of microbridge structures are arranged. The interconnect layer comprises a plurality of conducting interconnect channels providing an electrical connection between the microbridge structures and input contacts on the ROIC such that the microbridge structures are in electrical contact with, but are separated from, the readout silicon integrated circuitry. As the interconnect layer separates the microbridge structures from the ROIC, the detector material, typically a ferroelectric material, may be fabricated on the microbridge structures at a deposition or anneal temperature which is not limited by the avoidance of damage to the ROIC. Deposition temperatures of at least 500° C. or, preferably, at higher temperatures e.g. 700° C.-900° C.

Abstract: A device for indicating whether a rise in temperature above a predetermined value has occurred includes a support member, such as a label, on which a temperature-sensitive material is deposited. The material includes a large number of fracturable microcapsules containing a medium which changes from a solid state to a liquid state at the predetermined temperature value. The viscosity of the medium in its liquid state and the material of the support member are chosen such that the distance d.sub.1 by which the medium flows across the support member after the fracturing of the microcapsules so as to activate the device is indicative of the time between activation of the device and cooling of the device to below the predetermined temperature value. If the temperature is subsequently allowed to rise above the predetermined value, the medium will again assume its liquid state and will flow further across the support member, reaching a distance of, say, d.sub.

Abstract: A display device is described which comprises a liquid crystal host material and an anisotropically emitting fluorescent guest material dissolved in the host material such that the molecules of the guest material align with the molecules of the host material. An electric field applied across the host material causes the direction of radiation emitted by the guest material incident on an interface between two materials of different refractive index to vary so as to control the amount of radiation emitted by the display.

Abstract: A thermochromic liquid crystal display comprises a layer of short pitch cholesteric liquid crystal material between two walls. An absorber covers the back of the rear wall. At least one wall is surface profiled with a fine grating to align the liquid crystal material. Typically the grating pitch is 0.05 to 12 .mu.m. The profile may be fine on one wall e.g. 0.05 to 12 .mu.m pitch, 0.1 .mu.m depth and coarse e.g. 125 .mu.m pitch groove width 100 .mu.m, depth 10 .mu.m on the other wall. The cholesteric pitch is arranged to give the desired a selective reflection of light whereby the display is observed to change color with temperature. Using thin flexible walls small displays may be cut from large sheets of embossed polyester plastic materials.

Abstract: A thermal imaging device uses a compensated cholesteric liquid crystal mixture as its thermo-optic conversion element. The mixture is obtained by mixing two cholesteric liquid crystals, one with a left-handed twist and the other with a right-handed twist. The twists cancel at a compensation temperature, the mixture thus having infinite twist at this temperature. The device is designed to operate with the mixture held in the region of the compensation temperature.

Abstract: An active matrix addressed liquid crystal display is described, each liquid crystal cell within the display having two electrodes each carried on a surface of a different one of two insulating plates. Each cell is connected via a respective transistor to a pair of address lines each address line within a pair being connected to different cells within the array, and each line within a pair being carried on a different plate. Synchronized electrical pulses are applied to the address lines to switch on selected cells within the array, the sense of the pulses on one of the lines being periodically changed.

Abstract: A display device which is corrected for vibration, for example between screen (4) and the electron gun (2) in a C.R.T. (1). The device comprises an optical system (6) on the observer side of the screen (4) for directing the light from a small part of the screen (9), onto which the electron beam is directed at intervals, onto a photocell (10) which detects the position of the light spot. The output signal from the photocell is processed in a circuit (5) to provide a correction signal which is applied to the deflection system (3) of the C.R.T. to reduce the deviation of the light spot from the position it would have in a vibration-free environment.

Abstract: A color cathode ray tube display device which is compensated for color distortion due to, e.g. vibration, comprises means (9-12) for producing signals representing the respective color light outputs from the phosphor screen (5), means (13) for comparing the signals with the corresponding color impact video signals and means (14) to provide a correction signal to reduce any deviation between the signals.

Abstract: A touch sensitive switch with a liquid crystal cell and a circuit for measuring capacitive changes when the cell is deformed by touch. The cell has a layer of a liquid crystal material between slides bearing electrodes. Capacitive changes are detected for example by a comparator or by a bridge circuit which includes one or more cells. Touching one cell unbalances the bridge. The area of cell that is touched may be coincident with or separate from a display area. For some types of cells extra sensitivity is achieved by maintaining a voltage across the cell between a critical and saturation value.

Abstract: A liquid crystal display comprises a layer of cholesteric or smectic liquid crystal material contained between a front and rear wall. A pen having a tip is caused to move across the front wall causing an observable change in the liquid crystal under the pen tip. The change in liquid crystal material may be between its grandjean or planar state and focal conic state. This change may be caused by local pen tip pressure, heat, light or electric field. Erasure of observed information is by flexing of the liquid crystal layer. Alternatively heating and cooling, or an electric field may be used to erase the information. A resistive layer covers the front wall so that the instantaneous position of the pen can be fed through bus bars to a computer. This computer compares the electrical version of an observed signature on the display with a stored signature.

Abstract: A temperature indicating device comprising a series of liquid crystal cells each of which contains a liquid crystal material having a different composition, the composition varying from cell-to-cell, and each of which cells exhibits the grandjean state whereby temperature is indicated by iridescence of the cells, the cells being such that the liquid crystal material in each has a clearing point at a different selected temperature in a series of temperature in a temperature range of interest and that each of the cells is such that its liquid crystal material does not revert immediately to the grandjean state on cooling from the isotropic liquid state wherein the improvement comprises the cells having a construction such that the liquid crystal material of each cell undergoes, on cooling from the isotropic liquid state, the transition isotropic liquid state to focal conic state, without reverting immediately to the grandjean state.

Abstract: A liquid crystal display comprises two transparent slides containing a thin layer of liquid crystal material which may be nematic or cholesteric. Addressing electrode structures on the inner faces of the slide allow voltages to be applied across the layer to cause an observable display effect. The voltage at which an observable display occurs is temperature dependent. Sensing electrodes are connected in series with a reference impedance (Z.sub.f). With a constant supply voltage (V.sub.o) across the sensing electrodes and reference impedance (Z.sub.f) the voltage (V.sub.LC) variation is used to control the voltages applied to the addressing electrode to compensate for temperature variations in the layer.

Abstract: A display comprises a plurality of addressable display panels each having a display zone for displaying visual information and arranged in a formation so as to collectively provide a composite display of increased area. A fibre optic image transform construction is arranged in front of the display panels for transforming an image collectively provided by the panels into a corresponding continuous image in which discontinuity between adjacent panel display zones is eliminated.

Abstract: A d.c. electroluminescent panel comprises a transparent substrate, a transparent first electrode film, a phosphor layer, and a second electrode film. Application of a voltage across the phosphor layer causes it to emit light.In this invention the phosphor layer is produced in two layers, a first semi-insulating thin layer of activator doped phosphor and a second electrically conducting layer of phosphor.

Abstract: A color display system, for example an electronic data display or a color television system incorporates a display screen, for example a cathode ray tube phosphor, and at least one liquid crystal color filter. The screen emits light in the form of visual information in at least two colors, and the filter is controlled electrically in such a way that the colors transmitted by the screen may be switched according to input signal used to energize the screen.