Abstract: An improved system is described for providing approximately equalized illumination at all points between first and second opposite portions of a total internally reflecting cell. The system comprises in addition to the cell, a source of radiation of at least one selected wavelength, means for directing the radiation along a plurality of paths, and means for introducing the radiation in at least two of the paths into first and second opposite portions of the cell. Means can be provided for varying the penetration angle of the radiation into the cell.

Abstract: A fiberoptic fluid level sensing mechanism is provided which is operable for performing fluid level sensing as applied particularly to a mixing and dispensing device. The mechanism embodies light projecting means supported in the device so as to be positionable in juxtaposed relation to an external light source and operable to project the light rays received from the light source towards the exposed end of the fiberoptic rod. Photoelectric means is supported in juxtaposed relation to the opposite end of the shaft, and more particularly the other end of the fiberoptic bundle. In accord with the mode of operation of the mechanism, light rays from the external light source are projected through the light projecting means into the interior of the mixing chamber wherein they are operable to light the latter. As the opaque material in the chamber is dispensed, the level thereof decreases until the exposed end of the fiberoptic bundle is rendered visible.

Abstract: A wand suitable for scanning the universal product code (UPC) symbol uses a light emitting diode for illuminating the symbol and a silicon photodetector for receiving the reflected energy. A single optical fiber is coupled to the diode and to a portion of a second single fiber for conducting narrow bandwidth visible light centered about 6,500 A to the terminus of the wand. The reflected light energy from the symbol when it is scanned by the wand is transmitted to the silicon photodetector via the said second single fiber which is also coupled to a third single fiber which conducts the reflected light energy to the silicon detector.

Abstract: A fan-shaped beam of penetrating radiation, such as X-ray or .gamma.-ray radiation, is directed through a slice of the body to be analyzed to a position sensitive detector for deriving a shadowgraph of transmission or absorption of the penetrating radiation by the body. A number of such shadowgraphs are obtained for different angles of rotation of the fan-shaped beam relative to the center of the slice being analyzed. The detected fan beam shadowgraph data is reordered into shadowgraph data corresponding to sets of parallel paths of radiation through the body. The reordered parallel path shadowgraph data is then convoluted in accordance with a 3-D reconstruction method by convolution in a computer to derive a 3-D reconstructed tomograph of the body under analysis. In a preferred embodiment, the position sensitive detector comprises a multiwire detector wherein the wires are arrayed parallel to the direction of the divergent penetrating rays to be detected.

Abstract: A method and apparatus for producing X-rays having any selected one of a plurality of specific different wavelength spectra greatly facilitates X-ray fluorescence analysis of samples to detect constituent elements. In the X-ray source, an electron beam is directed to any selectable one of an array of primary targets of different composition. X-rays from the selected primary target may be utilized directly or caused to impinge on any selected one of a plurality of secondary targets, which are also each of differing composition to cause the secondary target to emit a specific X-ray spectrum characteristic of that secondary target. Analysis of the X-ray fluorescence from a sample irradiated by a plurality of different specific selected X-ray spectra enables identification and measurement of particular chemical elements in the sample.

Abstract: A dual path analyzer and a single path analyzer are disclosed, each for determining the concentration of one or more gaseous components in a mixture of gases. The preferred analyzer is a single path instrument which includes a source of infrared energy, a detector for the energy, a sample cell for the gas mixture positioned between the source and detector, and a filter wheel having a plurality of filters and a source blocking device positioned between the sample cell and detector for sequentially interposing the filters and the source blocking device between the source and the detector. Means are provided for amplifying the output signal of the detector and for processing the signal to provide a direct readout display which indicates the concentration of the gaseous components being analyzed.

Abstract: A photovoltaic device comprising a polycrystalline base having an electrically conductive grid affixed to the surface of the device to which illumination is to be applied, said grid effecting a rectifying junction with the base and at the same time functioning as a current carrying contact, said grid being arranged so that substantially all of the individual crystallites are contacted at least once thereby, while at the same time maintaining the coverage of the base by said grid to a minimum.

Abstract: A photoelectric detector in which partial light beam obfuscation caused by dirty windows is balanced out by providing two beams of light passed through the gaseous medium in which smoke or the like is to be detected, the beam windows being subject to substantially equal accumulation thereon over a period of time of soot or the like which causes the windows to become dirty or clouded. The windows are so spaced that the respective beams pass different distances through the smoke. The relative beam intensities as received are compared by connecting photoresponsive devices in a bridge circuit. A meter is connected to the bridge and preferably calibrated to read directly in Ringlemann numbers.

Abstract: The embodiment of the invention disclosed herein is directed to a solid state seed sensor which includes a light-emitting diode for directing a quantity of light to a pair of photoresponsive transistors. The light-emitting diode and photoresponsive transistors are maintained within a housing structure wherein all electronic components are mounted, such housing structure being formed of two halves with interconnection between circuit portions being accomplished through sealed passages formed through the housing halves. The light-emitting diode and associated resistor are maintained in one housing half while the remaining electronic circuitry, including the photoresponsive transistors, are maintained in the other housing half.

Abstract: The roughness of a surface is determined by directing a laser beam, or other electromagnetic radiation, onto a number of small areas of the surface in turn and measuring intensity of radiation scattered from the small illuminated areas with detectors arranged at a number of angles to the surface. Both the height of surface irregularities and average statistical wavelength may be found without physical contact with the rough surface.

Abstract: A photodetection device includes a photosensor usefully responsive to electromagnetic energy of a first band of wavelengths. An energy conversion unit is optically coupled to the photosensor for receiving incident electromagnetic energy of different, longer wavelength and emitting, in response, electromagnetic energy within the band of first wavelengths.

Abstract: A source of ultra violet light is directed onto the teeth of a patient via a mouthpiece which engages the gums above and below the tooth lines. A camera is attached and pictures may be taken of the teeth. By detecting differences in ultra violet absorption and reflection on the teeth, the detection of carious lesions may be undertaken in the relatively early stage of their development. Furthermore, deposits of dental plaque may be photographed readily and easily. The mouthpiece which may be disposable, is detachably securable to a base and is shaped at the mouth engaging end to engage the gums and hold the lips clear of the teeth during photography. It may be positioned in several locations relative to the mouth so that all of the teeth may be photographed and a mirror assembly may be attached so that the lingual and occlusal surfaces of the teeth may be photographed.

Abstract: An improved web scanning inspection system that includes a fixed standard web swatch containing representative objectionable defects in the path of the scan beam at the onset of each scan in order to calibrate inspection system discriminator thresholds. Gating and logic circuits are arranged to extract amplitude and duration characteristics of the defect related portions of the signals generated by scans across the standard swatch material. These are then used to actuate an alarm whenever the inspection system discriminator circuits fail to detect the objectional defects in the standard web swatch.

Abstract: A photo-optical imaging system suitable for use in an electronradiography system which produces an electrostatic charge image at an electrode. An electrode having a photoconductor layer and a transparent electrical conducting layer, with the charge image at the photoconductor layer. A light beam and various arrangements for scanning the beam over the photoconductor layer through the transparent layer for selectively transferring charge to the electrically conducting layer through the photoconductor layer as portions of the photoconductor layer are illuminated by the beam, and a data storage unit for receiving and storing data corresponding to the magnitude of charge at the photoconductor layer.

Abstract: This invention relates to presence sensing systems and more particularly to such systems which utilize beams of radiant energy, such as light beams, to detect the presence of a person or an object within a predetermined space. Additionally the invention relates to presence detecting systems combined with self-checking means to ensure that the detection system is operating properly.

Abstract: An automatic focus control device has an optical system including an image scanner. The image scanner is disposed between a range-finding lens and at least one light receptor element and on the path of travel of the incoming light towards the light receptor element through the range-finding lens. A mechanism is also disclosed for simultaneously measuring the object-to-lens distance and detecting the contrast of an image of the object projected on the scanner merely by moving the scanner in a direction diverging from the optical axis while a parallel relation between the plane of the scanner and the plane perpendicular to the optical axis is retained.

Abstract: A non-storage type image pick-up tube line scans a sample for picking up the fringes. A circuit responds to the maximum and minimum values of the output from the image pick-up tube generating a signal corresponding to the brightness of the fringes, signals corresponding to the positions of the bright and/or dark spots of the fringes, and signals corresponding to the spacings between a reference point and the positions of the bright and/or dark spots of the fringes.

Abstract: A height sensing device is provided which comprises a beam interrupter which swings into and out of the path of a beam passing from a light source to a photodiode. The beam interrupter is a disc rotatably mounted on a swinging sensor. The disc has a slot eccentrically located about the rotational axis of the disc. For adjustment, the disc may be rotated relative to the sensor to bring a portion of the slot into the beam path and then locked in such a position onto the sensor.

Abstract: Disclosed is a photo-image memory panel composed of an electroluminescent element which exhibits electrical polarization effects upon light excitation. Under the conditions when the panel is biased by DC voltage or DC offset voltage, light irradiation is applied to the panel to establish a light-activated polarized electric field of which the intensity is controllable in dependence upon a photo-image desired to be written into the panel. Then, the photo-image written into the panel is held while maintaining the polarized electric field. Thereafter, application of a predetermined voltage pulse enables the reading out of the photo-image in the form of light emission. Alternatively, in case of an electroluminescent element of which the light emission versus applied voltage characteristics involve the hysteresis phenomenon, a train of alternating current pulses are employed as reading-out pulses to maintain light emission corresponding to the read-out image.

Abstract: Improved circuitry for increasing the sensitivity of an electron-capture ionization detector includes a closed-loop feedback circuit which varies the frequency of pulses which are applied to the detector. The circuit responds to greater concentrations of predetermined compounds such as gases by increasing the pulse repetition frequency and responds to lower concentrations by decreasing the pulse repetition frequency, always tending to keep the current flowing in the detector circuit near a constant preset value. The pulse frequency will then vary directly with the concentration of sampled compound in the detector, and simple frequency-to-voltage conversion devices can be used to signal such concentrations. .Iadd.