Abstract: There is disclosed a variety of arrangements for tapping a portion of the signal power from an optical fiber waveguide without requiring that the fiber be terminated or broken. Power is coupled out of the fiber waveguide, which typically includes an inner core surrounded by a lower refractive index outer cladding, by disposing a dielectric body in a coupling relationship with an intermediate length of the fiber from which all or most of the cladding has been removed or, alternatively, which is bent to cause a portion of the power to radiate out of the inner core into the outer cladding of the fiber. The dielectric body couples power out of the fiber provided its index of refraction is approximately equal to, or greater than, that of the fiber cladding material. The power coupled out by the dielectric body is converted to a representative electrical signal by a photodetector disposed adjacent to the dielectric body.

Abstract: An erasable optical memory array having at each storage location a non-crystalline, semiconductor threshold switching device. The threshold voltage of each switching device is strongly temperature dependent and each switching device has a finite recovery time when switched to its low resistance state. Means are provided for periodically sampling each of the switching devices with voltage pulses repetitive at a first frequency and having a first voltage level sufficient to switch to the low resistance state only those switching devices heated above room temperature by a thermal image. Additional means are provided to sample the switching devices at a second frequency greater than the first frequency and at a voltage level less than that of the first voltage level to maintain the switched devices in the low resistance state upon removal of the thermal image.

Abstract: The invention relates to a noctoviser comprising an image intensifier tube and a cascade high-voltage generator in which the intensifier tube is connected to the output of the high voltage generator via a parallel connection of a resistor and an avalanche diode.

Abstract: Signal control apparatus which includes a control element in the form of a short section of fiber optic material which can be displaced by depression of a flexible plate or push button into alignment with adjoining sections of fiber optic material.

Abstract: This disclosure relates to a vital type of an optoelectronic phase inverting circuit arrangement employing a plurality of cascaded photon coupled isolators. Each of the photon coupled isolators includes a light emitting diode and an associated light responsive transistor. A source of periodic input signals is coupled to the photon coupled isolators so that electrical energy is converted to light energy by the light emitting diodes to control the conductive conditions of the respective light responsive transistors whereby the periodic input signals are inverted 180.degree. barring the presence of a critical component or circuit failure.

Abstract: Photovoltaic generation of voltages well above the bandgap results upon absorption of radiation by a dipolar dopant within a transparent polarized pyroelectric body. Generation is by a charge transfer mechanism in accordance with which electrons are transferred from excited absorbing species. A photovoltage of greater than a thousand volts has been observed in Fe.sup.2.sup.+ -doped LiNbO.sub.3.

Abstract: The pulse generator comprises a rotating transparent disc having a line pattern along its circumference and which is moved past an equally spaced line pattern of a fixed disc segment. The line patterns are scanned photoelectrically and the light-dark changes are converted into corresponding electrical pulses. The rotating disc and the disc segment are formed of thin plastic sheeting, and the rotating disc has two metal discs secured to respective opposite sides thereof out of the area of the line pattern thereon. One of these discs is formed with a peripheral groove into which the disc segment, which is fixed to a base, extends and bears against the rotating disc. The line patterns are provided on the outer surfaces of the disc and disc segments, whose inner surfaces are in surface-to-surface engagement to slide on each other in the area of the patterns under a slight pressure.

Abstract: A device for measuring the irradiation energy impinged upon a target within a fixed period, having a photo-electric receiver impacted by irradiation. Such devices have become known by the designation "Lux hour meter". They are used, e.g. for tests, by which the influence of irradiation energy on the properties of materials, e.g. textiles, shall be determined.

Abstract: A device is described for determining the linear displacement of a machine tool component with the aid of a grating which is mechanically connected to the component, which grating is disposed in the light path between a light source and a light-sensitive element which converts the incident light into an electric signal. The light-sensitive element is a multiple photo-cell which consists of a row of line-shaped photo-diodes which by means of an electrical switch are consecutively connected to an electronic circuit which processes the signal which is produced in the photo-diodes.

Abstract: This invention relates to a photoelastic load measurement device which measures the load on the cable of the crane by measuring the strain in a particular structural member of the crane and is calibrated to operate an alarm, indicator and/or recorder. A source of polarized light directs a beam of light through a photoelastic plate to an analyzer plate and a photocell. The photoelastic plate is subjected to stress from the structural member which varies with the load on the cable of the crane. The stress in the photoelastic plate subjects the beam of polarized light to temporary double refraction (birefringence), and the intensity of the light received by the photocell through the analyzer plate is dependent upon the degree of retardation of the light in the photoelastic plate. The output signal from the photocell is amplified to operate the alarm, indicator and/or recorder. The device includes apparatus which automatically compensates for changes in ambient temperature and variations in boom angle.

Abstract: The present invention relates to photosensitive device comprising a plurality of superposed semiconductive layers, wherein grooves are hollowed on the face exposed to the irradiance in order to reach and to pass through the junctions upon which the operation of the device is dependent and filled with a passivating agent transparent to the incoming light, the improvement being that the sizes of the grooves are selected in order to obtain a maximum efficient volume exposed to the irradiance close to the junctions upon which the operation of the device is dependent and to minimize the the cross-section of the junction.The present invention permits to obtained more efficient photothyristors and phototriacs.

Abstract: A pulse discriminator circuit for use in a closed loop scanning and positioning system for finding and positioning white blood cells. The surface of a slide is scanned to produce an optical signal which is converted by a sensor into an electrical signal. This signal is applied to the pulse discriminator circuit which provides an output pulse only when a white blood cell is being scanned. The output of the pulse discriminator is coupled to a logic circuit which produces signals that are used to drive the microscope stage to cause the white blood cell to be positioned within a small aperture in the optical system.

Abstract: The present invention provides a measuring apparatus comprising at least four photocells adapted to be simultaneously, synchronously displaced in a common plane on respective linear paths for scanning a projected image of a zone to be measured, said paths being arranged to intersect at a single point whereby the photocells are caused to move radially relative to that point in scanning the image.

Abstract: Improved apparatus for grading and sorting of tobacco wherein the tobacco is dropped onto a continuously moving conveyor from which it is passed over an end plate and is scanned by one or more detectors suitably located in a housing mounted above the end plate, the detectors producing a signal indicative of the reflectivity of the desired tobacco leaf which signal controls an ejection system for separating the desired from the undesired leaf. The invention includes new structure for the end plate, detector housing and light source housing.

Abstract: A photocell smoke detector comprising a housing defining a dual section smoke chamber having a first smoke sensing chamber and a second compensating chamber, a smoke sensing photocell coupled to the smoke sensing chamber and a compensating photocell coupled to the second chamber, a light source coupled to the compensating chamber and transmitting a beam of light generally parallel and away from the photosensitive surfaces of the two photocells, and a light trap communicating with the smoke sensing chamber and fabricated of layers of corrugated media sandwiched between relatively flat liners whereby light is absorbed in the flutes of the corrugated media and smoke is enabled to pass freely into and out of the smoke sensing chamber.

Abstract: In a system which automatically analyzes laboratory slides, the adjustable objective lens is automatically focused. A beam splitter splits light from the slide into two parts. One slide image is projected to an actual image plane where it is converted into electrical signals representing the optical characteristics of the slide. The other slide image is projected to a parfocal image plane at which two light sensing devices for the focusing system are positioned. One light sensing device is in front of the parfocal image plane and the other is behind the parfocal image plane. These light sensing devices produce electrical signals representing the position of the actual image plane with respect to the desired image plane. The electric signals are differentiated and then applied to a comparator which supplies pulses to a stepping motor which moves the objective lens.

Abstract: In a system which automatically analyzes laboratory slides, the adjustable objective lens is automatically focused. A beam splitter splits light from the slide into two parts. One slide image is projected to an actual image plane where it is converted into electrical signals representing the optical characteristics of the slide. The other slide image is projected to a parfocal image plane at which two light sensing devices for the focusing system are positioned. One light sensing device is in front of the parfocal image plane and the other is behind the parfocal image plane. These light sensing devices produce electrical signals representing the position of the actual image plane with respect to the desired image plane. The electric signals are differentiated and then applied to a comparator which supplies pulses to a stepping motor which moves the objective lens.

Abstract: A system sensitive to light pulses which are substantially synchronous with a selected pulsed light source containing frequency components within the pulse which are above a predetermined frequency. A signal for exciting the selected pulsed light source is frequency modulated and connected to an AND gate as well as to the pulsed light source device. The pulsed light is received and conditioned producing a received signal which is also connected to the AND gate. Gate output occurs only during the period of time the received signal is in time coincidence with the frequency modulated pulsed light source excitation signal. Additional light pulses transmitted in the immediate area of the receiver by additional light pulse transmitting devices having frequency components within the light pulse above the predetermined frequency may be sensed by the receiver, but will not produce output at the AND gate unless in time coincidence with the frequency modulated signal.

Abstract: In a system which automatically analyzes laboratory slides, the adjustable objective lens is automatically focused. A beam splitter splits light from the slide into two parts. One slide image is projected to an actual image plane where it is converted into electrical signals representing the optical characteristics of the slide. The other slide image is projected to a parfocal image plane at which two light sensing devices for the focusing system are positioned. One light sensing device is in front of the parfocal image plane and the other is behind the parfocal image plane. These light sensing devices produce electrical signals representing the position of the actual image plane with respect to the desired image plane. The electric signals are differentiated and then applied to a comparator which supplies pulses to a stepping motor which moves the objective lens.

Abstract: To test optical transmissivity of exhaust gases from internal combustion engines without requiring cleaning of confining walls of pipes or tubes, a film of liquid is caused to adhere to the inner surface of a transparent tube or pipe section by rotating the tube or pipe section so that the film will remain at the inner wall due to centrifugal force; light is transmitted transversely of the pipe section and through the exhaust gas. The liquid is preferably continually renewed by applying fresh liquid to the inside of the rotating pipe section, excess liquid being removed from an overflow ridge.