Abstract: A method and apparatus is disclosed for enhanced laser-induced plasma spectroscopic analysis of unknown heterogeneous materials. The apparatus has high power pulsed lasers with their beams focused on the material, typically two colinear lasers providing two pulses in the ultraviolet and in the near infrared spectral area. The first laser pulse vaporizes a small volume at the surface of the material and produces a plasma which is subsequently enhanced by the second laser pulse. The optical emission of the plasma is analyzed with a colinear optical spectrometer. The pulsed spectrum is detected by a gated photodiode array detector or by an array of photomultipliers each individually positioned to detect a line emission representative of a given element present in the material. The combination of the two laser pulses, appropriately synchronized, provides a plasma emission that is significantly stronger than a single laser pulse of the combined energy of the two pulses.

Abstract: A method and apparatus for rapid in-situ spectroscopic analysis of unknown heterogeneous materials is disclosed. The apparatus uses a high power pulsed laser whose beam is focused on the material, typically a porous compound of unknown composition such as an amalgamated powder or a mineral sample. The pulsed laser beam vaporizes a small volume of the material and produces a plasma having an elemental composition which is representative of the material composition. The optical emission of the plasma is analyzed with an optical spectrometer. The pulsed spectrum is detected by a gated photodiode array detector or by an array of individually positioned photomultipliers, to detect a background emission and a line emission representative of a given element present in the material.

Abstract: A method and apparatus for determining surface molecular orientation and related properties of an opaque polymeric sheet relies on the detection of relative intensity of spectral reflectance in at least one polarized beam reflected from the surface of the sheet rather than transmitted therethrough. The relative intensity is affected by the preferential orientation of the polymeric chains. The method is fast and can be applied on-line at a speed of the running sheet as high as 1000 m/s.

Abstract: A method and an apparatus for monitoring simultaneously the temperature and the velocity of sprayed particles. The system is comprised of a sensor head attached to the spray gun, an optical fibre transmitting the collected radiation to detection apparatus, and a protective detection cabinet having the detection apparatus that incorporates two detectors. A two-slit or multiple-slit mask is located in the sensor head at the end of the optical fibre. For the temperature measurements, the particle emitted radiation collected by the sensor head is transmitted to two photodetectors, filtered by interference filters at two adjacent wavelengths. The particle temperature may be computed from the ratio of the detector outputs. To measure the velocity, the two-slit system collects radiation emitted by the in-flight particles travelling in the sensor field of view, which generates a double peak light pulse transmitted through the optical fibre.

Abstract: An optical inspecting apparatus and the method thereof, including a series of optical units for rapidly acquiring the three-dimensional surface profile of a moving object. Each optical unit contains a multiple-beam light source to project a number of luminous spots on the object surface which are imaged through a properly oriented line-array camera. The surface position on both sides of the object, and thus the object thickness, is inferred at the position of each luminous spot from an analysis of their camera image. The projected luminous spots are preferably elliptically shaped and the line array elements are elongated in a direction perpendicular to their longitudinal axis in order to reduce speckle and other optical noise. The described optical configuration results in a superior performance in terms of spatial resolution and response speed.

Abstract: The present disclosure describes an apparatus and a method for detecting the presence of flaws in a moving sheet of material. The apparatus comprises a light source for projecting a light beam; a beam shaping unit for shaping the light beam into a predetermined structured light pattern, and projecting the structured light pattern onto a portion of the surface of the sheet; an optical unit for collecting light emitted from the portion of the surface; and a light detecting unit for receiving the light collected by the optical unit and generating an electrical signal indicative of the intensity of the light generated from the portion of the surface. A signal processing unit is provided for filtering the electrical signal, the signal processing unit having predetermined characteristics specifically adapted to match an expected electrical signal corresponding to the predetermined structured light pattern.

Abstract: The degree of cure in a polymeric composite is evaluated in a simple, rapid and non-destructive manner by heating a surface portion of the polymeric composite to substantially curing temperature, over a predetermined period of time, and continuously monitoring with a non-contact temperature sensor temperature fluctuations of the heated surface portion during the predetermined period of time to obtain data comprising surface temperature values measured as a function of time. By processing such data including comparing with a calibration reference, for example by providing a curve of the measured surface temperature values against time and comparing with a reference curve, one can evaluate the degree of cure of the polymeric composite.

Abstract: A method for the detection of delaminated areas in coated materials or layered composites, which allows free-air operation and can be used to scan portions of bulky materials on the spot. This method which makes it possible to detect very small delaminated areas in a very short time (less than 1 millisecond), with a very high sensitivity and without creation of excessive thermal stress in the inspected material, basically comprises the steps of: focusing pulsed, thermal radiations onto the structure to be inspected to produce a vertical displacement of its coating by thermal expansion if a delaminated area is present at the coating-to-substrate interface, and detecting and measuring this vertical displacement if any, by interferometry, preferably laser-beam interferometry. An apparatus for carrying out this method is also disclosed.

Abstract: An optical system is described for monitoring the thickness of a translucent film either free-standing or coated on a reflective substrate. A polychromatic light beam is projected onto the surface of the sheet, and the transmitted light is detected at, at least, three wavelengths of which only one corresponds to an absorption band of the film material. By properly processing the three or more detected signals, an accurate evaluation of the film thickness is obtained irrespective of the presence of colored pigments in the material or of wavelength-dependent attenuation due to scattering at the film interfaces. Optical configurations are also described which avoid errors produced by interference fringes or front-surface reflections while simplifying the scanning of the sheet surface.

Abstract: An apparatus using optical techniques for simultaneously detecting surface defects and measuring the diameter of a wire coming out from an extruder. A combination of cylindrical lenses is used for projecting, perpendicularly across the longitudinal axis of the wire, a sharply focused laminar beam. This apparatus includes an optical source system for emitting optical rays, an optical system for focusing the rays on the wire, an optical detector system for receiving the rays and generating a detector signal to be processed by a signal processing system, the processing system generates an electric signal indicative of the amplitude of the defects and another electric signal indicative of the diameter of the wire.

Abstract: A thermally activated liquid ink printing head has a plurality of orifices in a wall of an ink reservoir, the ink retained in the orifices by surface tension. Electrical heating elements heat the ink in the orifices, the ink being caused to pass across to a paper sheet positioned adjacent to the orifices. The orifices may extend in a line across the head or may be in other predetermined patterns, such as for printing alpha-numerics a character at a time. The ink may be completely or partly vaporized. The heating current may flow through the ink.

Abstract: An electrostatic ink ejection printing head uses an ink reservoir having small holes in its wall, the ink retained within the holes by surface tension. An electrostatic field is produced at each hole, as required, to overcome the surface tension and cause the ink to move into contact with a paper sheet to produce a dot. The holes can be in any desired predetermined formation. An electrode can be positioned opposite each hole, the paper between electrode and hole, or an electrode can be formed around or on either side of each hole. The electrodes are pulsed as necessary.

Abstract: In a liquid ink printing system, ink is supplied to a reservoir at a constant pressure, and viscosity of ink in orifices in the reservoir wall is decreased by electrically heating the ink in the orifices. By this means the amount of ink deposited on a paper sheet moving past the orifices can be varied.

Abstract: A liquid ink printer uses electrostatic control of ink flow along paths defined by strips of hydrophilic material. The strips may be discontinuous, with a narrow gap across which ink is urged to flow by application of a voltage to an electrode, or a gate member may be pulled down onto a strip to prevent ink flow. In a further arrangement drops of ink are extracted from the ends of the strips and accelerated towards a printing position by an electrode pattern.