Abstract: The display has a video signal receiver and a store with a capacity to hold one picture of the video signal. Row-output devices enable the video information for respective rows of pixels to be taken out from picture store, and each has a bit extractor to separate out one bit of the information for each pixel of the respective row. The resultant signal is passed to pixel drivers which operates on a lattice formed of ferroelectric liquid crystal pixel-elements, which are time-multiplex addressed according to a predetermined sequence, each row being addressed a plurality of times for each picture. In the addressing groups of the rows are set simultaneously, each group consisting of a plurality of rows spaced apart in the addressing sequence such that the rows in a group form a series with adjacent rows having a temporal separation in the addressing sequence exhibiting a geometric progression with the common ratio N being an integer corresponding to 2 or more.

Abstract: A system for positional determination includes an array of piezoelectric sensor electrodes connected to an array of output lines via resistors for providing a binary code in response to activation of the sensor electrodes; and an array of further output lines also connected to the array of sensor electrodes via resistors for providing a binary error code in response to activation of the sensor electrodes. By combining the resultant binary code and binary error code, an accurate determination of the position along the array of activation of the sensor electrodes may be achieved.

Abstract: A display device in the form of a slim screen projector has a beam-splitter and a reflector co-planar and in contact with each other. Incident light from a light source strikes the beam-splitter and reflector and a portion thereof is directed towards a mirror. Light from the mirror then passes through a louvre-screen via the beam-splitter and strikes a viewing surface on which a viewable image is formed.

Abstract: A fluorescent tube (2) is made of a plastics material containing at least one organic fluorescent dye and attached to the inner surface of this tube is a barrier layer (3) for absorbing ultraviolet radiation, and attached to the inner surface of the layer (3) there is a phosphor layer (3a).

Abstract: In a thick film water track, irrespective of track thickness or the material of which the track is constructed, the optimum track width is found to be in the range of from 1.2 mm to 2.1 mm. Further, for a given resistance, the track is longer and may be conformed to a pattern to give improved temperature distribution. Additionally disclosed is a heating element having a number of thick film electrically resistive tracks applied to the surface of an electrically insulative substrate and a switch for selectively connecting one or more of the tracks to a power supply. The resistance and hence the operating temperature of the heating element may be varied by changing the track or tracks connected to the switch.

Abstract: A financial transaction card 2, such as a check guarantee and/or credit card includes a tagging element 4 of a high permeability, low coercivity magnetic material, such as Ni Fe. The tagging element 4 is arranged in magnetic communication with a magnetic stripe 10 of relatively hard magnetic material or in a region of the card 2 used to record identifying data, such as user details, so as to be deactivated when the user details are recorded on the card 2. The provision of the element 4 enables card blanks to be monitored by an electronic article surveillance system during manufacture or prior to issue.

Abstract: A thermal detector arrangement includes a number of channels, each including a collimator for collimating incident radiation to a respective optical filter. Each optical filter has a respective radiation passband characteristic with one having a passband spanning the passbands of all of the other optical filters. The radiation passed by each optical filter is passed to a thermal detector, which preferably is in the form of a thermally isolating membrane acting as a radiation absorbent cavity and supported by a semiconductor substrate. The output signals from the thermal detectors are multiplexed, amplified by an amplifier having voltage offset compensation and digitally processed to provide an indication of a fire to be sensed.

Abstract: A tungsten halogen lamp producing infra red radiation, for example for cooking or heating, has an envelope of high silica content material sealed at each end by a pinch seal. A gas fill is at a room temperature pressure of 250-750 mm Hg. A portion of the envelope at each end is clear and the rest contains an opacifier which reduces transmission of visible light. A suitable opacifier is red, being produced by the reduction of copper oxide dispersed in the high silica content material. The envelope is produced by butt joining clear end sections and a tube of material containing opacifier.

Abstract: A luminaire is disclosed comprising a fluorescent plastics outer sleeve having a configuration such that a high proportion of the fluorescent light generated within the sleeve is emitted as visible light. The sleeve includes a fluorescent dye, which dye is excited by a blue phosphor discharge.

Abstract: A ballast circuit includes a load circuit. A reservoir capacitor is effective to supply charge to the load circuit. A capacitive charge pump circuit is effective to transfer charge from a charge pump capacitive circuit to the load circuit and to the reservoir capacitor. The load circuit includes the primary winding of a transformer. A secondary winding of this transformer is for connection across a discharge lamp. In operation of the ballast circuit, the primary winding of the transformer drives the capacitive charge pump circuit.

Abstract: A method of operating a display comprising a lattice of pixel elements, includes the step of time-multiplex addressing collections of pixel elements. This addressing step includes using a first shift register means to designate operation of a second shift register means to select a function to be performed. If the second shift register means is in bypass mode, then the first shift register means is effective as a mask to specify which of the stages in the second register means should be bypassed, and allows non-sequential group addressing of the pixel elements. Such an arrangement of first and second shift register means is suitable for use in controlling the addressing of collections or rows of pixel elements; the function to be selected by the second shift register means is the strobing of the collections or rows.

Abstract: A thermal imaging device is described including an array of pyroelectric sensor elements. Each element is at least partially supported by a respective pillar of an intrinsic polymer material. The pillars provide an electrical path between the elements and a signal processing means.

Abstract: A method of addressing a display device comprising a matrix of separately operable pixels is provided. The method comprises the step of applying across a given pixel a voltage waveform comprising a latching pulse and an auxiliary pulse of amplitude smaller than the latching pulse. The amplitude of the auxiliary pulse is modulated to determine the latching effect of the latching pulse.

Abstract: In a liquid crystal display, each pixel is formed of four separately energizable areas which have relative light outputs in the ratio 1:2:4:8 respectively, thereby allowing a range of 16 grey levels to be achieved by appropriate selection of areas. Each of the areas has a number of segments, which are spaced-apart but concentrically arranged, in order to have the same average position, so that different bit patterns cause the pixel to change brightness only, without any apparent positional change.

Abstract: A mounting arrangement is provided for mounting a lamp fitting on a planar support, it comprises: a plurality of carrier means secured to the lamp fitting, each carrier means having at least one linear series of parallel tooth members; and a plurality of support members, each support member including means for locating the support member on a respective carrier means and at least one engagement surface for engagement with a chosen tooth member such that in use of the mounting arrangement, the engagement surface is maintained in engagement with the tooth member by the weight of the fitting acting on the engagement surface.

Abstract: A display device is formed by a matrix of surface-stabilized bi-stable ferroelectric liquid crystal elements each being separately settable by a matrix driver. To provide brightness control or color in the display, all the elements of the matrix are set in accordance with a portion of a signal for display and the amount of light passing through the matrix for that setting is controlled in accordance with the binary significance of the respective portion of the signal. This control is produced by varying one of the activation duration or intensity of a light source, such as sets of fluorescent tubes in accordance with the binary significance of the brightness information in the input signal. Half of the frame time (T) is used for the numerous setting operations on the matrix of elements and half is used for the backlighting operations of the various settings.

Abstract: A ballast circuit for the operation of a discharge lamp includes a bridge rectifier. A capacitive energy storage device and a load circuit are connected in series across the bridge rectifier. A charge circuit provides charge to the capacitive energy storage from the load circuit in a potential so as to add to the potential from the outlet of the bridge rectifier.

Abstract: A signal identification system, suitable for producing an identification code on a sound track recording is described. The system includes an encoder 209 effective to eliminate a variable sequence of frequency bands from an audio signal and insert a sequence of code signals into the frequency bands. As the sequence of frequency bands varies throughout the sound track recording, the presence of the code is difficult to detect.

Abstract: A method of manufacturing a color filter for a liquid crystal cell comprises forming a plurality of patterns, each of a respective dye intermediate material, on a carrier element. The patterns of dye intermediate materials are then brought into contact with a substrate layer, supported on a glass substrate, under the application of heat and pressure. The substrate layer, such as a polyacrylonitrile layer, contains free acid groups which interact with the dye intermediate materials to form the colors of the color filter in the substrate layer. The method permits the actual formation of the colors on the substrate to be effected in a single alignment step, minimizing wastage of the relatively expensive glass substrates. Furthermore, as the dyes providing the colors of the filter are chemically part of the substrate layer, they are very resistant to leaching by the liquid crystal materials.

Abstract: A drive circuit comprises a first waveform generator and a second waveform generator. Each waveform generator is capable of generating at least two voltage states and the instantaneous voltage of the first waveform is never less than that of the second waveform by more than a defined amount. The circuit further comprises a plurality of means to produce respectively a plurality of output waveforms by selectively switching to either the first waveform or the second waveform and a gate array to control the selective switching. The arrangement is such that each of the plurality of means to produce respectively a plurality of output waveforms is capable of producing an output waveform having at least four voltage states. The drive circuit produces a plurality of outputs suitable for driving a matrix-addressed display.