Abstract: The present invention provides systems and methods for non-destructively detecting material abnormalities beneath a coated surface. A terahertz (THz) illumination unit illuminates an area of the coated surface. A detection unit detects light reflected from the illuminated area of the coated surface, and a processing unit images the illuminated area of the coated surface from optical characteristics received from the detection unit.

Abstract: A method and apparatus for the qualitative and quantitative spectroscopic investigation of elements present in a liquid sample using the laser spark. A series of temporally closely spaced spark pairs is induced in the liquid sample utilizing pulsed electromagnetic radiation from a pair of lasers. The light pulses are not significantly absorbed by the sample so that the sparks occur inside of the liquid. The emitted light from the breakdown events is spectrally and temporally resolved, and the time period between the two laser pulses in each spark pair is adjusted to maximize the signal-to-noise ratio of the emitted signals. In comparison with the single pulse technique, a substantial reduction in the limits of detectability for many elements has been demonstrated. Narrowing of spectral features results in improved discrimination against interfering species.

Abstract: A transducer system for detecting and measuring the displacement and/or vibration of objects placed in contact therewith. The system includes a reflective target for reflecting incident light and vibrating in unison with a contacted object. Fiber optics guide light from a light source to the target via a light coupling medium, and back to a signal generator. A truncated spherical member, providing the target and the object contacting surface, is biased by Belleville springs. The light guiding fiber optics, springs and light coupling medium are sealed from the hostile environment of the transducer.

Abstract: Alignment marks on a semiconductor wafer comprise a first alignment island projecting from a surface of the wafer and a second alignment island having substantially the same height as the first alignment island and surrounding the same with a slit therebetween. The slit is utilized as a pattern for aligning with an alignment mark on a photomask. Preferably the alignment marks are formed on the grid line region of the wafer.

Abstract: An apparatus for establishing a desired position of a tool, including a means for moving the tool along a particular axis, a laser for providing a beam of coherent light along an axis which intersects the axes of tool movement and which is located so that the tool can block at least a portion of the beam, a detector of beam blockage, and a controller for tool movement which can respond to signals from the detector.

Abstract: A system for determining the attitude of an airborne platform such as a terrain image sensor includes a digital image correlator for comparing successive overlapping, instantaneous images of the terrain which are recorded by a second, two-dimensional image sensor whose image plane is oriented parallel to that of the terrain image sensor. The second sensor generates an instantaneous master image and a subsequent slave image which at least partially overlaps the master image in terms of the terrain which is viewed. The master and slave images are approximately registered and a correlation is performed. A plurality of points on the slave image are correlated with the corresponding terrain points on the master image. The correlation is performed by selecting a plurality of spatially distributed patches of pixel arrays which are mathematically superimposed on and are moved about the slave image to determine the locations where the maximum of gray scale correlation occurs.

Abstract: A detection device is disclosed for determining particle size from particle effected light scattering in a sensing region receiving the particles in a gas carrier, such as air, and a laser beam to illuminate the sensing region. Background light from molecular scattering is reduced to a level that enables light scattered by particles having a size of at least as low as about 0.1 micron to be sensed in a high background of molecular scattering such as, for example, where molecular scattering can exceed the 0.1 micron particle's scattering by one hundred times. High molecular scattering is generated whenever the gas volume being viewed is large as is required for high flow rates, high molecular density (high pressures), or large gas molecules.

Abstract: A road surface illuminated by sunlight is scanned with a laser beam at right angles to the direction of travel, the intensity of the laser beam being intensity modulated with a predetermined frequency; laser beams reflected from the road surface are received and optically filtered to filter out light having frequencies outside that of the laser beam. The optically filtered laser beam strikes a plurality of beam position sensing elements from which respective electrical signals are derived. The resulting electrical signals are then multiplexed and electrically band-pass filtered wherein the center frequency of the band-pass filtering coincides with the frequency at which the laser beam is intensity modulated.

Abstract: A method and apparatus for the detection of undesirable surface deformities is disclosed wherein a known (linear) light pattern is reflected off a fabricated part having a nominally smooth surface, the reflected light pattern subsequently being analyzed for distortions from the expected light pattern. The extent of the detected distortions may be quantified by the use of a computer having appropriate software, in order to identify and quantify unacceptable surface deformities.

Abstract: An apparatus (31) and method for measuring the refractive index of an optical recording medium substrate (34) wherein an angle of incidence of a polarized beam (33) is set at an oblique angle of incidence with the substrate (34), the polarized direction of the polarized beam (33) is varied for the substrate (34) in this state, the transmitted or reflected light beam by the substrate is received by a light receiving means (36) through a light analyzer means (35) in the crossed Nichol state and the received light amount for the polarized angle is measured and is compared with a theoretical formula so that the refractive index in the thickness direction of the substrate can be measured.

Abstract: A flow cell for use in a fibre diameter measurement apparatus to obtain preferential alignment of the fibers in which fibers are caused to flow through a passage (14) the walls (16 and 16a) of which diverge in the direction of flow thereby causing forces to act on the fibres to rotate the ends of the fibres towards the diverging sides of the passage and thus rotate the fibers to a larger angle to the direction of flow.

Abstract: A housing for a particle flow-through apparatus comprises a body member having a passageway therethrough including a region through which substantially one particle at a time may pass in a normal direction of flow. An operative plunger is positioned in the passageway so that the plunger is depressible into the passageway. Depression of the plunger creates increased pressure in the passageway for dislodging clogged particles or debris from the region in a direction reverse to the normal direction of particle flow.

Abstract: A portable analyzer is disclosed. The analyzer comprises in combination a housing, an optical system comprising a light source, a detector, and one or more means for activating the optical system in generating a signal in response to a test element, means for manually moving the test element from a first position to a second position corresponding to a point of initiation of an operative condition of the optical system, means biasing the moving means toward said first position for controlling movement of the test element from the second position to the first position, means cooperative with said optical system, for processing the signal, and means, cooperative with the means for processing the signal, for displaying the processed signal.

Abstract: An optical apparatus comprising a laser light source, an optical system for focusing a beam of light from the laser light source onto an object surface through an objective lens and a spatial filter disposed at the entrance pupil of the objective lens or at a position conjugated with the entrance pupil, wherein the origin of the divergence of the laser beam having an angle of divergence emitted from the laser light source is projected on the entrance pupil of the objective lens by the optical system.

Abstract: The technique for optically scanning a finger to produce a fingerprint image involves positioning the finger surface to be optically scanned so that it is exposed and, in particular, is not pressed against a platen. A slit light beam along the length of the forward part of the finger is circumferentially rotated about an axis about the nominal center of the finger. A reflected slit light beam carries modulation information which is focused on a linear array of photo-electric transducers to provide the fingerprint image. The interrogating light is coherent, substantially collimated, light. The plane of the interrogating slit light beam and the plane of the reflected modulated slit light beam are coplanar thereby establishing an illumination plane. The illumination plane is parallel to the axis of the finger and is rotated about that axis during the interrogating scan.

Abstract: An apparatus for determining crystal orientation comprises: a polarizer for polarizing an incident light beam; a polarization analyzer for selecting light having a selected polarization direction in Raman scattered light; and a synchronizer for enabling synchronous rotations of the polarizer and the polarization analyzer.

Abstract: A system for measuring the weft or mesh serial position in textiles, in which the angular position of the weft/mesh series is measured for determining the angle of distortion passing over a partial amount of the length thereof, includes an illumination measuring system which measures values of light from a light source either passing through or reflected from the textile fabric to be tested, in a substantially linear range, and an adjusting assembly which reciprocally and oscillatingly rotates the linear range about a central angle to adjust the linear range at an angle relative to the textile fabric; rotating or measuring the reflection or transmission values in several discrete equidistant angular units; a group of memories for storing the measured values corresponding to at least a few angular units; and a digital unit connected to the memories for comparing the stored values in calculating a distortion angle in response to such comparison.

Abstract: Concentration gradients in samples to be evaluated are detected by measuring the deflection of a probe light beam passed through the sample using the principals of Shlieren optics. Specific chemical compounds in a sample can be detected and identified by supplying excitation energy to the sample where such energy is selected to be absorbed by the chemical compound to be specifically identified and not by other compounds in the sample. The absorption of the excitation energy by the absorbing compound produces a temperature gradient within the sample which causes deflection of the probe light beam and signals representative of such deflection may be separated from signals representative of deflections caused by other refractive index gradients present in the sample. A light emitting diode may be used to generate the probe light beam.

Abstract: An optical sensor head has deep, pitched grooves or screw threads in the walls of the gas channel, and a gas flow swirled along the grooves to protect optics against atmospheric debris and moving particles such as is generated by an industrial process. The grooves are pitched to support swirling motion of the gas. Use of swirled flow increases allowable flow velocity and diverts incoming particles toward the channel walls. The windows of an optical profiler, for instance, are protected against the smoke and weld spatter created by a metal-inert-gas welding torch.

Abstract: Apparatus to measure the size of an optic zone of a lens, particularly a contact lens or intraocular lenses, and the refractive power of that optic zone includes an illumination system with a light source and a first lens train producing a collimated beam of light from the light source, and a second lens train including an observation system coaxial with the illumination system and focusing the collimated beam so that the observation system allows an observer to observe a magnified image of the lens to be measured. The lens to be measured is disposed on a mounting plate positioned in the collimated light beam between the first and second lens trains. A planar knife edge is positioned within the focused light beam of the second lens train so that it occludes a part of that beam. A micrometer or similar device is attached to the mounting plate so as to measure the observed size of the optic zone or zones of the lens.