Abstract: The invention relates to a method for preparing an emulsion by membrane emulsification enabling control of the dispersed phase size and size distribution by interrupting extrusion of the dispersed phase.

Abstract: A frame 2 for an image such as a picture 16 is formed from a microlens array. Such an array produces an apparent optical plane which is not coplanar with the real plane of the array. This produces the visual effect of the picture 16 being divorced from the frame 2 and an illusion of depth is created as between the frame 2 and the picture 16.

Abstract: Apparatus for irradiating an area with a controllable pattern of light comprises a laser (2), which illuminates a spatial light modulator (6). The resulting spatially modulated light then passes to a cholesteric liquid crystal polymer beam-splitter (10) which reflects it to an image surface (13) of an endoscope (12). The endoscope relays it to another image surface (40) whence it is focussed on the area to be irradiated. This light may be used for photodynamic therapy.

Abstract: A method of assaying for a ligand in a sample involves incubating the sample in contact with a specific binding partner for the ligand carried on one surface of an optical structure, irradiating the structure at a suitable angle or range of angles to the normal such that the resonance and/or total internal reflection of the radiation occurs within the optical structure and/or the layer of specific binding partner, and analyzing the radiation in order to determine whether, and if desired the extent to which and/or rate at which the generated radiation and/or optical characteristics of the optical structure are altered by complex formation.

Abstract: A color sequential illumination system, such as, for example, a backlighting system for a liquid crystal display (LCD), comprises lamps for emitting blue, red and green light. The red and green light is provided by lamps including fluorescent dyes having optical decay times similar to a phosphor material used to provide the blue light. In this manner, the blue, red and green emissions can be fully synchronized with electrical signals used to energise the lamps, enhancing color range and color quality. Furthermore, if the fluorescent dyes are carried in plastics materials, then trapping and concentration of the light generated may also be achieved, providing enhanced brightness for the LCD for a given power input.

Abstract: A screen for use in a front projection system includes a section capable of reflecting light of certain, predetermined wavelengths more than light of other wavelengths. The screen appears black or dark gray when viewed in broadband light. The screen provides for enhanced contrast between incident projected and ambient light. A projector for use with the screen has a light source capable of emitting the predetermined wavelengths.

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: A specifically-reactive sample-collecting and testing device possessing a cavity or cavities each having a dimension small enough to enable sample liquid to be drawn into the cavity by capillary action, wherein said cavity includes an electrode structure for making measurements of one or more electrically measurable characteristics of the sample, and wherein a surface of a wall of the cavity optionally also carries a coating of a material appropriate to the test to be carried out in the device.

Abstract: A required visual signal for direct observation is produced from a first source of light in the presence of a second source of light, such as ambient light. Light is transmitted from the first source to a defined surface or defined region distant from the first source. A means for modulating light is operated between at least a first mode and a second mode. This operation is synchronized with a varying of the intensity of at least one of the sources of light at or above a given frequency equal to or greater than the critical fusion frequency for the size and luminance of the required visual signal. When the modulating means is in the first mode, this allows the required visual signal to be directly observed on the defined surface or in the defined region. When the modulating means is in the second mode, this allows the effect produced by any light from the second source incident on the defined surface or in the defined region to be reduced.

Abstract: A scanned 2- or 3-D modulated light pattern originating from a light source and represented by a matrix of pixels is projected onto a defined surface or into a defined region distant from the light source. A plurality of means for modulating light one operated between at least a first mode and a second mode. This operation is synchronized with the scanning of the matrix of pixels so that:(a) respective modulating means is in the first mode when its associated plurality of pixels are being scanned; and (b) a respective plurality of pixels are not being scanned when its associated modulating means is in the second mode. When a modulating means is in the first mode, it allows light to be distributed from the defined surface or the defined region. When a modulating means is in the second mode, it allows the effect produced by any light incident on the desired surface or in the defined region to be reduced.

Abstract: A specifically-reactive sample-collecting and testing device possessing a cavity or cavities each having a dimension small enough to enable sample liquid to be drawn into the cavity by capillary action, wherein a surface of the cavity carries an immobilized reagent appropriate to the test to be carried out in the device, and wherein said surface is a surface of a transparent solid plate to act as a light-transmissive waveguide and forming a wall of the cavity, said plate having an edge which is substantially optically smooth and transverse to the plane of the plate.

Abstract: A method of optical analysis of a test sample which comprises a sample material with light-absorbing, scattering, fluorescent, phosphorescent or luminescent properties, which sample is partly in a liquid phase and partly bound to an adjacent solid surface, to discriminate the respective parts of said sample material which are located in the liquid and bound to said solid surface: comprising the steps of providing as said solid surface a surface of a transparent solid optical waveguide, and measuring light from the sample material bound to said solid surface that has passed into and through said transparent solid optical waveguide with total internal reflections and emerged from said waveguide at an angle that deviates from the optical axis of said waveguide by an angle appreciably less than .alpha., where.alpha.=arcsin.sqroot.(n.sub.2.sup.2 -n.sub.1.sup.2)where n.sub.2 is the refractive index of the material of the waveguide and n.sub.

Abstract: A polar coordinate display of full 360.degree. arc comprises an electrically responsive medium between two electrode bearing substrates. One set of electrodes is configured as a number of concentric spirals, allowing connection at the display periphery. The other set of electrodes may be radial or counter spiral. The display may be addressed using a set of isogonal signals--for example psuedo-random binary sequence coded signals.

Abstract: A liquid crystal display includes a liquid crystal cell formed by enclosing a thin layer of a cholesteric liquid crystal material between two slides. A set of electrode structures is formed on each slide so that voltages may be applied to the liquid crystal material causing an observable display effect. Voltages are supplied to the electrodes in sequence by driver electronics under the control of a logic unit which also controls a variable voltage source supplying voltages to the driver electronics. The logic unit controls the drive electronics to give an R.M.S. voltage V.sub.x at elements required to be at an OFF state and an R.M.S. voltage V.sub.c higher than V.sub.x at elements required to be in an ON state. The logic unit also controls the voltage source to reduce its voltage output to both OFF and ON elements simultaneously while maintaining the ratio of V.sub.x and V.sub.c for a period while information displayed is to be changed.

Abstract: A polar co-ordinate display of full 360.degree. arc comprised of electrode bearing substrates each side of a layer of dyed phase change liquid crystal material. One set of electrodes comprises concentric spirals, the other set comprises radials. The display is multiplex addressed using four select waveform signals. These four signals V.sub.1, V.sub.2, V.sub.3, and V.sub.x satisfy the following conditions:RMS(V.sub.x -V.sub.i)=V.sub.p, i=1, 2 or 3;RMS(V.sub.1 -V.sub.2)=V.sub.p ; RMS(V.sub.1 -V.sub.3)=V.sub.0where V.sub.p is an upper threshold voltage, and V.sub.0 a saturation voltage for dyed phase change hysteresis, and may be of the coded form;V.sub.1 =,1010,;V.sub.2 =,1100,;V.sub.3 =,0101,;V.sub.x =,0110,.These may be generated using two 2-bit registers with exclusive OR-gate feedback.

Abstract: An apparent three dimensional image is produced from a two dimensional image by causing the two dimensional image to appear on a saddle shaped surface. This saddle shaped surface may be a real surface such as a light scattering glass or a surface in space formed by an optical component such as an aspheric lens or lenticular array. The two dimensional image may be produced by a cathode ray tube e.g. a television receiver, a slide or film projector, or a non-emissive display such as a liquid crystal display.

Abstract: A random pattern generator is used to generate waveforms displayed on a cathode ray tube. A plurality of waveforms are built up to form an observed pattern for use in the design of textiles or carpets. To form a waveform a series of numbers Xi (i=1, 2, 3 . . . ) are generated each representing an amplitude value of a waveform X. Each value of Xi is translated into a number Y in a series of numbers Z, then incremented by a changeable amount A to obtain a different value Zi which collectively are used to trace out a pattern on the cathode ray tube. The observed pattern changes with each value of A. Generation of Xi and Zi may be from programmed read only memories. The series Zi may be a pseudo random sequence of numbers.

Abstract: Two waveform traces to be simultaneously displayed are sampled and converted to a series of digital sample values. An electro-optic display, e.g. a liquid crystal or electroluminescent display has a first m set and a second n set of electrodes arranged in a matrix having m.times.n display elements. The matrix may be in cartesian XY or r .theta. polar co-ordinate format. In one form the m set of electrodes are arranged in two subsets alternating with one another forming a subset m.sub.o of odd rows and a subset m.sub.e of even rows. Coded waveforms V.sub.i, each having a different shape over a period T are applied to one subset m.sub.o of the m electrodes while another voltage is applied to the other subset m.sub.e of m electrodes followed by application of V.sub.i to the subset m.sub.e and the other voltage to subset m.sub.o. Selected ones of the coded waveform V.sub.

Abstract: An analogue display with a panel having an electro-optic medium contained between two sets of electrodes. One set is arranged in a plurality of segments each divided into inner and outer portions. Each portion is planar and has a plurality of digits. The digits of one portion are interposed alternate with, and in between, the digits of the other. The other set has a planar meander configuration modified by an electrode interposed in its folds. The sets of electrodes when registered one over the other define two subsets of different selectable index positions. Selected alternating voltages are applied simultaneously to the electrodes maintaining the panel ON at two selected index positions and OFF elsewhere a dial shaped display area which is other than circular or arcuate, e.g. Preferably the voltages are selected from the set (+2V, +V, -V) of RMS magnitudes (2V.sub.c, V.sub.c, V.sub.c) where V.sub.c is equal to the threshold voltage of the panel.

Abstract: A liquid crystal color display comprises a cathode ray tube which emits at two or more wavelengths, a liquid crystal cell, a neutral analyzer and two color selective polarizers. The cell is switched in synchronism with different images supplied to the cathode ray tube so that the different images are observed in the different colors simultaneously. The cell is respectively switched ON and OFF by application of signals at a low frequency f.sub.1 and a high frequency f.sub.h. To avoid a patch appearance due to different parts of the liquid crystal having different twists a gap is allowed between switching the signals f.sub.1 and f.sub.h so that the total shear of the liquid crystal may be kept below a critical shear value.