Abstract: A real time stereo fundus viewer is disclosed which uses IR illumination introduced either corneally or through the sclera, arranged for frontal or rear illumination of the posterior regions of the eye and displayed using two miniature false colour displays; with the option of OCT.

Abstract: An automated system, method or computer program product for providing emergency communications can include an emergency communications application and a MyFlare emergency communications server. The MyFlare emergency communications application can run on a mobile device and can be configured to, when activated, interface with the MyFlare emergency communications server to send preconfigured emergency messages to a preconfigured set of emergency contacts. Different emergency profiles can be preconfigured for which different emergency messages can be sent. Additionally, a different set of emergency contacts can be assigned for different emergency profiles. The emergency communications application can be configured to capture additional information, such as but not limited to GPS location of the device, photo, video, or sound recording, in preconfigured time intervals.

Abstract: The optical receiver includes a photodiode, a preamplifier and a length of transmission line. The photodiode may be connected to the preamplifier, either via the transmission line, or directly between the preamplifier and the transmission line, that is, the transmission line is connected as an open circuit. The transmission line 14 may comprise a coaxial cable, stripline, or any other suitable form of transmission line. The input impedance of the preamplifier should be designed to match the characteristic impedance of the transmission line. The noise of the preamplifier associated with the transmission line has a periodic spectrum dependent upon the length of the line with peaks at odd multiples of f' and minima at even multiples of f'. The value of f' is related to the length of the transmission line in accordance with: f'=v/4L where v is the propagation velocity, typically 2/3 the speed of light, and L is the length of the transmission line.

Abstract: An optical communications system comprises a pluarality of optical transmitters coupled by a common channel or bus to an optical receiver. The optical transmitters are operated using time division multiplexing (TDM), each TDM period being word or message length. The optical transmitters each comprise a least one current source to drive the light source, for example a laser, in response to the data signal, to vary its output power about a steady level which is the average of the maximum and minimum values. Therefore each current source may be controlled as to increase its output gradually (preferably sinusoidally) to reach the aforesaid mean level at the beginning of a TDM period and to decrease it in the converse way after the period ends. Such an arrangement avoids the need for guard time before and after the TDM time period, thereby increasing channel efficiency, and improves receiver sensitivity by reducing quantum shot noise due to steady light from inactive transmitters.

Abstract: A microphone arrangement, suitable for a telephone handset, comprises an array of microphone transducers, conveniently pressure transducers arranged at the vertices of a cube. Signal processing circuitry derives from the transducer outputs signals representing the magnitude and direction of the pressure gradient of the sound field at the array. In response to these signals, the microphone transducer outputs are weighted so as to direct the directional sensitivity lobe of the microphone towards the source of the maximum sound detected thereby.

Abstract: A crossover arrangement for optical conductors, each in the form of a rod of light-transmissive material, includes a multifaceted, e.g. polyhedral member having pairs of mutually parallel opposed facets. Each pair of facets extend in a direction transverse, preferably perpendicular, to that in which a second pair of facets extend. The end face of each optical conductor is abutted against one of the facets of the polyhedron. Each facet has a coating of a material having a lower refractive index than that of the polyhedron or the optical conductors. Light entering the polyhedron from one conductor passes across the polyhedron and into the opposite conductor, being constrained to stay within the polyhedron by the coatings on the side facets. Preferably the polyhedron member is a cube and the optical conductors are of square cross-sectional shape.

Abstract: A mounting arrangement for mounting an optical conductor on a "photonic" backplane provides for simple, accurate positioning during installation and easy access to, and removal of, the optical conductor when in service. The optical conductor constitutes a "busbar" in that it has a series of reflector surfaces spaced along its length to permit distribution or aggregation of several light signals. In one embodiment, an individual support is provided at each reflector/circuit card location. Each support is a seating member which houses a lens to couple light between the optical conductor and the circuit card. In another, preferred, embodiment the optical conductor is housed in a channel in a guide rail mounted upon the backplane. Separate cover members are releasably mounted upon the guide rail adjacent each circuit card. Each cover member has an aperture and lens to couple light between the reflector and the circuit card.

Abstract: An eye-position sensor for use in an eye-activated optical transducer in which a spatial filter is used to modify light reflected from the eye to form a substantially rectangular pattern on a quadrantal array of contiguous sensors. This arrangement provides a substantially linear change in the output signal from the sensors in response to an equivalent movement of the eye.

Abstract: Light is diverted from one optical conductor to another optical conductor by a suitably oriented non-planar reflecting surface at the junction of the two optical conductors. The non-planar surface comprises facets arranged so that light incident on one facet from one optical conductor will be reflected at that facet onto an adjacent facet, and at the adjacent facet to the other optical conductor. The arrangement of facets is such that the Snell's Law condition for total internal reflection at each facet can be satisfied for a wider range of ray directions than is possible for a single planar reflecting surface. The arrangement is useful for optical backplanes now being proposed for use in computers and telecommunications equipment.

Abstract: At a fiberoptic tap used for monitoring purposes, one fiber, having a certain mode volume is spliced to a second fiber having a relatively lower mode volume. Consequently, in passing from the first fiber to a second fiber, some light is radiated away from the splice. This radiated light is directed to a photodetector. The tap is particularly advantageous for transmitter power monitoring since the radiated optical power is superfluous to that light which is capable of transmission by the line fiber.

Abstract: A position indicating system for affording an indication of the instantaneous position of a movable member, such as a rotating shaft, comprises means for producing light in different color bands directed on to a suitably coded structure movable in accordance with movement of the movable member or coded structure which itself carried filter means for separating light into different colors. Optical fibre means is located for receiving colored light passing through the movable coded structure and for transmitting light to light detector means for producing an output dependent upon the light received by the optical fibre means and indicative of the instantaneous position of the movable member.

Abstract: A pyrometer system for the measurement of the temperature of a primary source of heat which might be contaminated by radiation from a transient spurious source of heat at a higher temperature, and in which the presence of radiation from the spurious source can be detected or identified by spectral discrimination. The received radiation is separated into two spectral components of which a second component comprises a significantly higher proportion of radiation emitted by the spurious source than does the first component. The ratio of, or the difference between, the magnitudes of the radiation in the second and first components is used to identify or detect the presence of spurious radiation and to produce an error, or flag, signal which is used to inhibit operation of the pyrometer or to cause it to hold the last received `good` reading before the occurrence of the spurious radiation.