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:
An anti-dazzle filter (1) comprises a transparent substrate (2) to which are laminated a vertical polariser (3) and a yellow filter (4). The device may be incorporated into sunglasses or into a visor to reduce glare caused by bright sunlight. Alternatively, it may be used to reduce light back-scattered by fog or mist.
Abstract:
A method of manufacturing integrated circuits in which a number of conductive test structures (7) for monitoring electromigration are formed at different points on the wafer on which the integrated circuits (1) are being manufactured. Electrical connections (5) are formed between the test structures (7) on the wafer, and the resistance of the current path constituted by the structures (7) and connections (5) is monitored to determine whether any of the test structures (7) have failed.
Abstract:
A method of improving the electrical characteristics of a thin film (1 or 9) formed on a substrate (3 or 11) by a Langmuir-Blodgett process. The method comprises immersing the film (1 or 9) in a fluid (5 or 13) and applying an electrical potential to the substrate (1 or 9) such that a self limiting electrochemical reaction within the fluid (5 or 13) causes any voids in the film (1 or 9) to be preferentially filled.
Abstract:
A filter with a tailored output characteristic for example useable as a comb filter is fabricated by producing two or more biconical tapered portions in an optical fibre. The manufacture is controlled so that the resulting concatenated couplers have specified pass-band characteristics.
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:
A compound forming a tilted smectic liquid crystal phase has the general formula R1-O-CH2-CH2-O-{Z}-R2 in which: R1 is an aliphatic radical containing carbon and hydrogen atoms and optionally one or more oxygen atoms each linked to separate carbon atoms and having a total number of carbon or of carbon and oxygen atoms not less than 1 and not more than 15; R2 is an aliphatic radical containing carbon and hydrogen atoms and optionally one or more oxygen atoms each linked to separate carbon atoms and having a total number of carbon or of carbon and oxygen atoms not less than 4 and not more than 18; and {Z} is an aromatic or alicyclic core of a type suitable for a liquid crystal.
Abstract:
A coupler for use in wavelength division multiplex having a pair of monomode optical fibers (10, 11) with adjacent portions fused together (12) and a biconical taper in the fused portion. The fused portion (12) has a near-circular cross-section such that it has substantially zero birefringence.
Abstract:
A fibre optic device which can be used as an attenuator or a sensor. The fiber has a biconical taper which can be immersed in a medium having a higher refractive index so that light transmission through the fibre can be used as a sensor in measuring temperature, refractive index. When used as a tuneable attenuator electrodes are mounted in contact with the medium so that it can be heated to vary transmissivity through the fibre.
Abstract:
A semiconductor device incorporating two superlattices (1, 3) in the GaAs/AlGaAs system separated by a relatively thick layer (5) of GaAlAs. The device displays negative differential conductance.