Abstract: An apparatus and method for measuring the de-watering performance of a forming section of a papermaking machine is disclosed which includes a laser instrument assembly having first and second laser displacement meters laterally spaced and supported above an upper run of a paper forming fabric. A head box deposits paper stock consisting of a water/fiber mixture on top of the upper run. An adjustable carrier stand supports the laser instrument assembly above the upper run of the forming fabric. The first laser displacement meter is disposed in a first position above the forming fabric so that a laser beam of the first laser meter is reflected off of the paper stock which is deposited on top of the forming fabric. The second laser displacement meter is disposed in a second position above said forming fabric so that a laser beam of the second laser displacement meter is reflected off of a bare edge of the forming fabric.

Abstract: It is an object to provide a method of sorting semiconductor lasers, capable of appropriately removing semiconductor lasers which can cause a so-called sudden death in use. After a first current within a range of 50 to 150% the maximum rated current is supplied to the semiconductor lasers for a predetermined period of time, a second current is supplied within a range of 120 to 250% the maximum rated current for a short period of time. Semiconductor lasers which are destroyed or degraded in output characteristics are removed as defective devices.

Abstract: An optical transducer, such as used in an ultrasound system, includes a signal laser which generates an optical signal the frequency of which varies in correspondence with acoustic energy incident on the transducer. An optical cavity in the signal laser is disposed such that incident acoustic energy causes compression and rarefaction of the optical cavity, and this displacement varies optical frequency generated by the laser. A laser pump coupled to the lasing medium is adapted to apply selected levels of excitation energy appropriate to the generation and detection of acoustic pulses. The signal laser alternatively is adapted such that the refractive index of the optical cavity is varied in correspondence with the incident acoustic energy to modulate the optical frequency of the light generated by the signal laser.

Abstract: This invention provides for a fiber optic moisture sensor. The sensor is comprised of a housing and a support positioned within the housing. The support is coated with a film. A first and second light guides are positioned within the housing and communicate illumination to and from the film. A reflective surface is positioned within the housing facing the film. The film comprises an optically transparent polymer and a salt complex of a metal ion and an organic compound. The salt complex is capable of absorbing moisture and emits a fluorescence signal when excited by light at the appropriate wavelength. The fluorescence signal can be quenched when the salt complex absorbs moisture. An apparatus incorporating the sensor and a method of making the sensor are also provided.

Abstract: An arrangement for holding together a package of boards to be used in the manufacture of printed circuits by applying glue to an edge of the package or by applying glue into holes formed in the boards.

Abstract: A non-imaging optical telescope having a variable field-of-view utilizes an atomic resonance filter within its non-reflective tube. The atomic resonance filter received incoming light through the aperture of the telescope and re-emits the light to an optical sensor. The field-of-view is a function of the distance of the atomic resonance filter from the aperture. A positioning mechanism is provided to move the atomic resonance filter within the tube, thereby varying the field-of-view.

Abstract: A technique for examining surface structures which differ in respect of refractive index and/or height modulation of the surface comprises introducing these surface structures into a plasmon surface polariton field and scanning them by means of surface plasmon microscopy.

Abstract: A technique for the simultaneous measurement, in real time, of the changes in mode size, pulse length, and power of a wavetrain of laser pulses delivered by mode-locked or other pulsed laser systems contemplates directing respective portions of the beam along each of three beam paths. The beam portions along the first and second beam paths are subjected to respective, and different, degrees of focusing, and then passed through respective non-linear elements which generate radiation at the second harmonic. The first harmonic components are removed, and the second harmonic components are passed to respective first and second detectors which generate signals representative of the total second harmonic energy along each of the first and second beam paths. The beam portion along the third beam path is passed to a detector which generates a signal representative of the total energy in the beam pulse. The three signals are combined to give values proportional to peak power, pulse length, and mode size.

Abstract: A subpicosecond solid state optical correlator based on interference induced carrier modulation includes a photosensor circuit having a photoconductive element and a pair of opposed electrodes. A voltage difference is created across the electrodes to define an electrical field direction, and the element operates to generate charge carriers in response to optical energy incident on the photoconductive element. First and second optical signals are directed onto the photoconductive element to form an interference pattern thereon when the signals overlap in time and space. This interference pattern produces spatial modulation of the distribution of the carriers into lines or planes, at least some of which are not parallel to the electrical field direction. The resulting photocurrent is monitored to detect a parameter associated with the presence or absence of the interference pattern.

Abstract: Lines of various slopes and positions are generated simply in a computer aided manual drafting system. Such lines may be drawn with a modified puck manually movable over a surface to control the position of a cursor in an electronic computer display, and may be stored for later adoption in a manually directed computer aided drafting step. The puck senses two spaced positions on a surface over which it moves, thereby to define the slope of a line positioned with a datum point at the cursor location positioned by the puck in a conventional manner. Lines in this system are defined by two points in a coordinate system, namely a datum position point and a slope position point. This format affords simplified entry, processing and storage of line data in a computer.

Abstract: An electrical system preferably constructed as gas-insulated, metal-encapsulated switching system containing at least one electrical switch located in a darkened internal space is monitored by a device for detecting interfering arcs. In this arrangement, the light pulses emanating from the interfering arcs in the internal space are optically detected, conducted out and converted into electrical signals which are processed in an evaluating device. The monitoring device should be distinguished by a short response time. This is achieved by applying electrical signals, which are attributable both to interfering arcs and to regular switching arcs, to the evaluating device and by the fact that the evaluating device also contains a circuit arrangement which detects the variation with time of the electrical signals. In this circuit arangement, the electrical signals attributable to interfering arcs are distinguished from signals attributable to regular switching arcs.

Abstract: FM laser spectroscopy apparatus includes a single modulator for modulating a laser beam with first and second modulation signals (.omega..sub.1, .omega..sub.2). The two modulation signals are generated by mixing a signal from a first oscillator (.omega..sub.1 +.omega..sub.2)/2 and a signal from a second oscillator (.omega..sub.1 -.omega..sub.2)/2 and producing the two modulation signals (.omega..sub.1, .omega..sub.2). The modulator produces three groups of sidebands on the laser beam at the laser frequency plus and minus the two modulation frequencies and at plus and minus the difference between the two modulation signal frequencies. The apparatus provides practical high frequency FM spectroscopy as required for the observation of pressure broadened spectral features.

Abstract: The accuracy of measurements made to determine the extent of water vapor trapped upon encapsulation of an electronic device is significantly enhanced by carefully controlling the measurement technique employed. In particular, the encapsulant is generally punctured and the water vapor thus released is monitored. It has been found that to obtain an accurate measurement of the magnitude of the water vapor released, this measurement must be made within 0.1 second of the time of encapsulant punctured and released into a glass system. By using an absorption technique with suitable electronics, this time requirement is fulfilled and significantly more accurate quantitative measurements of entrapped water vapor are obtained.

Abstract: A simple optomechanical method and apparatus is described for substantially reducing the amplitude of unwanted multiple-interference fringes which often limit the sensitivities of tunable laser absorption spectrometers. An exterior cavity is defined by partially-transmissible surfaces such as a laser exit plate, a detector input, etc. That cavity is spoiled by placing an oscillating plate in the laser beam. For tunable diode laser spectroscopy in the mid-infrared region, a Brewster-plate spoiler allows the harmonic detection of absorptances of <10.sup.-5 in a single laser scan. Improved operation is achieved without subtraction techniques, without complex laser frequency modulation and without distortion of the molecular lineshape signal. The technique is applicable to tunable lasers operating from UV to IR wavelengths and in spectrometers which employ either short or long pathlengths, including the use of retroreflectors or multipass cells.

Abstract: A system for testing a wave guide arc detecting circuit for a microwave system is disclosed. Testing is accomplished by utilizing a pulsed laser source to generate pulses of optical energy which are used to simulate an electrical arc across the wave guide. The laser source is then positioned such that the pulsed output signal impinges upon the wave guide arc detector circuit to be tested. This is most advantageously accomplished by affixing the wave guide arc detector circuit to the wave guide in a fashion similar to normal operation. This enables the arc detecting circuit to view the end of the wave guide through the interior of the wave guide. The laser source is positioned such that the output pulse of the laser source impinges on the open end of the wave guide. The operational status of the wave guide arc detecting circuit is determined by measuring the elapsed time between the generation of the output pulse of the laser and the detection of the pulse by the arc detecting circuit being tested.

Abstract: An electro-optical measuring system is described wherein a laser or light beam is precisely translated in a straight line perpendicular to the direction of propagation of the beam at a uniform, repeatable speed to define a time-varying sensing field whose energy is picked up by a photosensor which yields an output signal. An object whose dimension is to be measured is inserted in the field whereby the output signal of the photosensor takes the form of a pulse whose leading edge is developed by the traversal of the beam across one edge of the object, thereby blocking passage of the energy to the photosensor. The trailing edge is developed by the traversal of the beam across the opposite edge of the object thereby restoring the energy to the photosensor. The width or time duration of the pulse is a measure of the distance between the two edges.

Abstract: Fiber optic waveguides exhibiting a blackout phenomenon can be used for temperature sensing. A temperature sensing waveguide can be used in such applications as maintaining a material within a selected temperature range, freeze protection viscosity control of liquids in pipelines, leak detection of cryogenic fluids, fire detection, application of heat-recoverable materials, battery charging, and fluid level detection. Novel waveguides exhibiting blackout at selected temperatures for use in these applications are described.

Abstract: A security system to prevent the unauthorized duplication of documents on standard electrostatic copiers. Paper substrates are coated with layers of carefully sized and spaced beads which break up the light emitted by a copier to a degree sufficient to preclude copying. In another embodiment, an original consisting of a paper substrate bonded to a reflective metalized film reflects light from the copier, and masks the image of any intelligence present on the substrate.

Abstract: A device for checking the functioning of a gas measuring apparatus which includes a tubular connection for the passage of a gas so that it can be directed through a tube mounted in the connection which has means therein such as a chemical for measuring the gas which is passing therethrough. The device comprises a translucent diffusing screen mounted on the tubular connection so as to be able to view through the screen and into the gas passage and a spring diaphragm connected to the tube having a side disposed in space relationship to the screen and viewable through the screen and gas between the screen and the diaphragm when the diaphragm is flexed in one direction in respect to the screen so as to position it closer to the screen.

Abstract: In a resin molded controlled-release product which comprises a volatile or elutable active agent dispersed in a substantially transparent and inert resin molded material, the improvement which comprises a colored material located inside or on the back surface of the molded product which is not visible through the product at the initial concentrations of the active agent, but is visible through the resin product at concentrations of the active agent at which the activity of the product is substantially extinct.

Abstract: A housing for a fire detector has a circumferential area including a series of vanes or slats, each positioned at an angle with respect to the tangent at the periphery of the housing. The angle is about 45.degree., which not only allows ready entrance of gases through the major portion of the "window" defined by the vanes, but also prevents particles from passing straight through the housing and out the other side. This effects good mixing of the gases, better detection of combustion particles, and also decreases the likelihood of spurious or incorrect signals due to extraneous air currents.

Abstract: A system and apparatus for providing a measure of ESI (equivalent sphere illumination) as a function of Lb (background luminance) and Lt (task luminance) and in which a pair of envelopes are provided each having a varying transmittance such that one envelope can provide an indication of the term (Lb-Lt) and the other an indication of Lb whereby ESI can be determined.

Abstract: The invention provides a substrate for positioning the end of one or more optical fibres in a reference plane. Each fibre is positioned by means of three right circular cylindrical dowels in a staggered arrangement on the flat trued face of a parallelepiped. The substrate may further comprise a single additional optical fibre bearing against the apertures of the transmission fibres and doing duty as a cylindrical lens for coupling each transmission fibre with the emissive zone of a laser diode.

Abstract: A device for use in checking and/or calibrating the accuracy with which a blood constituent concentration measuring instrument is operating. The device includes a capillary tube size member having annular bands marked on its outer surface. The bands are of predetermined axial extent and simulate centrifuged blood cell or other constituent layers. The axial dimension of each band is measured on the instrument which provides a visual indication of corresponding blood cell count. The blood cell count indicated by the instrument is then compared to the known blood count corresponding to the predetermined axial extent of the particular band measured. This device may be used to calibrate the instrument or determine the accuracy with which the instrument is operating.

Abstract: An optical apparatus for use in association with an optical fibre having a core member and a cladding member which surrounds the core member and which has a refractive index less than the refractive index of the core member, the apparatus including optical means adapted to examine light radiated at an angle through the cladding member and thereby determine the characteristics of the optical fibre and/or facilitate the application of an illuminating beam of light at an angle through the cladding member and to thereby excite a single mode in the optical fibre; and means for maintaining the angle between the light and the fibre axis substantially constant.

Abstract: An acousto-optical method and device for measuring the radiation produced by a transducer is described wherein such radiation is in the range of about 500 KHz to 10 MHz. The method consists of propagating ultrasound frequencies from the transducer through a transparent liquid medium in a cell, said cell having a transparent window or suitable device to provide a clear path for the radiation waves and passing a light through said cell at about a right angle to the direction of said ultrasound wherein the light is modulated in phase with the frequency of the ultrasound. The modulation of the light corresponding to the frequency of the ultrasound can be detected by a photo-cell measured and displayed on various devices. Further, a transducer can be calibrated absolutely using this method and apparatus from known constants and easily measured quantities. Moreover, it is readily adapted to measure the radiation of an unknown source to a known absolute source.

Abstract: The measurement of equivalent sphere illumination on a given task located in a lighted area is disclosed herein. This is accomplished by comparing a movably mounted task in the lighted area with the same task in a control area illuminated with sphere illumination. The task is viewed alternatively in the two areas in accordance with specific optical procedures to determine the equivalent sphere illumination on the task in the lighted area.

Abstract: A density check plate comprising a support having thereon a plurality of light absorbing filters, each of which has a light transmission limit wavelength at a different spectral wavelength and which completely and sharply absorbs light of a wavelength shorter than the wavelength of the light transmission limit wavelength.

Abstract: A waveform sampler, for cooperation with a conventional sampling oscilloscope, has, as part of a bridge circuit, two Gallium Arsenide photoconductors mounted on a 50 ohm stripline. One GaAs photoconductor, the sampling photoconductor, is illuminated. The other GaAs photoconductor remains dark and functions as a common mode compensating photoconductor. To sample an unknown electrical waveform traversing the stripline the electrical wave is optically strobed by illuminating the sampling GaAs photoconductor with pulses of light from a laser. To sample an unknown optical waveform the optical wave is focused on the sampling GaAs photoconductor and an electrical strobe signal is sent through the stripline. Outputs from each of the photoconductors are amplified in high input impedance FET amplifiers and after electrical compensation they are passed to a conventional difference amplifier. The difference output is further amplified and fed to a conventional sampling oscilloscope.

Abstract: The invention relates to a method of determining the modulation transfer function of a recording support or of an optical system. In the context of the invention, an optical system includes any components with finite apertures which are required for forming an image of an object. A coherent-optically produced scatterer of known noise distribution or with a known spatial frequency spectrum is used for determining the required modulation transfer function. The modulation transfer function can be determined through the density of transparency distributions present on the recording support.

Abstract: The present invention relates to a device for positioning and supporting apparatus, particularly for optical instruments in a laboratory, constituted on the one hand by a support rail and on the other hand by a clamp mounted to slide on said rail, the rail being constituted by a linear circular-sectioned tubular structure, the tubular section having four diametrically opposite radial fins projecting therefrom, the clamp is adapted to be positioned on two adjacent fins, the clamp comprising two side branches, one of which receives an adjustable locking member abutling an outer face of a fin.

Abstract: An accelerometer comprising a first glass plate mounted in a fixed position, a second glass plate mounted in spaced relation with said first plate and movable with respect to said first plate, an aligning agent coating the facing surfaces of said plates, a nematic liquid crystal mixture filling the space between said plates, means applying an electrical potential between the coated surfaces of said plates, and means for detecting optical characteristics within said liquid crystal mixture.

Abstract: To compensate for the nonspecific absorption in an atomic absorption spectral photometer an auxiliary illuminating source is provided in addition to the principal illuminating source. The need for moving parts and mirrors is obviated by mounting the principal and auxiliary radiation sources in fixed positions along a common ray path. The auxiliary source is constructed so that it is optically transparent and mounted adjacent the optical input with the radiation concentrated in an emission center common to both sources coinciding with the emission center of the auxiliary source. The sources are pulsed so that they are energized alternately.

Abstract: An on-line system for continuously monitoring the color, opacity and brightness of a moving web of paper or the like in which an optical shoe providing black and white backgrounds spaced in the direction of movement of the web supports a portion of the web below and generally in registry with an optical head made up of a light integrating sphere for directing light from a source onto the web over the shoe and a plurality of elongated sensing units mounted in the upper portion of the sphere and including a centrally located brightness measuring unit oriented generally perpendicularly to the web toward a point over the black background, four circumferentially spaced color tristimulus sensing units, each of which is oriented at an angle to the axis of the central unit so as to be directed at the same point as is that unit and a sixth opacity sensing unit angularly oriented with respect to the axis of the central unit so as to be directed toward a point over the white background spaced downstream of the first poi