Abstract: An air flow measurement device includes a connector conduit with a constant inner diameter wall for the air flow, a transverse restrictor plate located within the conduit with a plurality of generally uniformly spaced apertures extending therethrough, and an annular mounting piece secured centrally about the conduit for securely mounting a pair of air pipes to the opposite ends of the conduit in air-tight engagement therewith. The restrictor plate is maintained in the connector conduit by a swaging operation which causes it to be expanded outwardly into tight engagement with the conduit wall. A pair of tank valves are mounted, by a special saddle, to the mounting piece, and passages are provided through the mounting piece and conduit wall for communication with the interior of the conduit just upstream and downstream of the restrictor plate whereby a differential pressure meter may be connected to the valves to measure the difference in pressure to thereby determine the air flow rate.

Abstract: An optical fiber sensor for inducing a microbend in an optical fiber in the presence of the liquid phase as distinguished from the vapor phase of a fluid such as water. The sensor includes a chamber with an expansible block located therein, and a thin band is provided about the block of a dimension and tensile strength such that any increase in outward expansive force in the block due to an increase in the presence of the fluid in its vapor phase only will not cause the band to rupture; however, when any liquid enters the chamber, the band will rupture to allow the block to expand in a particular direction to move a pusher bar which, in turn, moves a puller wire to bend the fiber at a location remote from the chamber.

Abstract: A rigid cylinder is provided with small perforations to permit the entry of hydrocarbon containing liquids, gases or vapors, and the interior of the cylinder is lined with a sensor material which expands in the presence of hydrocarbons. The interior chamber enclosed by the sensor material is completely filled with an incompressible liquid, and one end of the chamber is sealed by a conventional pressure sensor so that the presence of hydrocarbons causes the sensor material to exert a pressure upon the incompressible liquid to create an output signal in the pressure sensor. A double-chambered device, with only one chamber being perforated and thereby exposed to the hydrocarbons, can be used to compensate the pressure sensor signal for ambient pressure or temperature changes.

Abstract: An optical fiber sensor for inducing a microbend in an optical fiber in the presence of a detectable fluid such as water includes a chamber with an expansible block located therein. When water enters the chamber, the block expands in a particular direction to move a pusher bar which, in turn, moves a puller wire to bend the fiber at a location remote from the chamber. A gap may initially be provided between the expansible block and the pusher bar so that the presence of water vapor within the chamber will not move the pusher bar but the presence of liquid water will.

Abstract: A scanning confocal optical imaging system is utilized to read or measure data magnetically recorded on a magneto-optic disk. The system includes a laser for producing a linearly polarized beam and a beam splitter for directing the transmitted beam to the disk and for deflecting a portion of the reflected return beam from the disk to a photodetector. A pinhole plate is placed between the beam splitter and the disk for restricting the size of the transmitted and reflected beams, and a polarizer is positioned between the beam splitter and the photodetector to receive the deflected return beam and provide an output that discriminates between the differing directions of rotation of the polarization plane of the transmitted beam by the magnetized area on the disk so that the direction of magnetization of the magnetized area can be read by the photodetector.

Abstract: A system for determining surface profiles of specimens such as semiconductor wafers includes a drive for mounting the wafer for oscillatory movement along a line and an optical imaging system overlying the wafer for focusing a beam on a small sport on the wafer and including a photodetector for detecting the reflected sport from the wafer. The spot is scanned along the line on the wafer while the focal depth of the imaging system is progressively changed while the photodetector and connected digital circuitry generate a plurality of spaced output signals for each scan along the line so that data comprised of a series of spaced signals are provided at a plurality of focus levels extending through the surface profile of the wafer. Computer means are provided for analyzing the data and providing a graphical output of the surface profile.

Abstract: A system for determining surface profiles of specimens such as semiconductor wafers and for making linewidth measurements thereon includes a drive for mounting the wafer for oscillatory movement along a line and an optical imaging system overlying the wafer for focusing a beam on a small spot on the wafer and including a photodetector for detecting the reflected spot from the wafer. The spot is scanned along the line on the wafer while the focal depth of the imaging system is progressively changed while the photodetector and connected digital circuitry generate a plurality of spaced output signals for each scan along the line so that data comprised of a series of spaced signals are provided at a plurality of focus levels extending through the surface profile of the wafer. Computer means are provided for analyzing the data and providing a graphical output of the surface profile from which accurate linewidth measurements are made.

Abstract: A semiconductor wafer scanning system includes a confocal optical imaging system with a laser beam being focused on a small spot on the wafer surface to be scanned. The optics include an objective lens located closest to the wafer with means being provided to vary the spacing of the lens from the wafer over small distances to thus change the focal plane of the system. The wafer may be independently driven in two orthogonal directions in a plane generally perpendicular to the imaging system to bring selected portions thereof into view of the optics. During scanning, the wafer is rapidly vibrated in one of the directions while it is slowly moved in the other direction with a series of digital output signals being provided by the light reflected back from the laser spot on the moving wafer to provide precise information for constructing a three dimensional representation of the surface pattern of the wafer.

Abstract: A confocal optical imaging system includes a laser for producing a linearly polarized beam which is transmitted through the optical elements of the system, focused on a small spot on the target, and reflected back through the optical elements to a photodetector where the reflectance from the spot is determined. The optical elements include a pinhole plate for restricting the size of the transmitted and reflected beams which plate, along with other of the optical elements, can produce unwanted reflections adding optical noise to the reflected beam from the target. A retardation plate between the pinhole plate and the target alters the polarization of the transmitted beam relative to the reflected beam so that a polarizer will discriminate between the true reflected beam signal and the unwanted reflections to thereby improve the signal-to-noise ratio at the photodetector.

Abstract: A confocal optical imaging system includes a laser for producing a linearly polarized beam which is transmitted through the optical elements of the system, focused on a small spot on the target, and reflected back through the optical elements to a photodetector where the reflectance from the spot is determined. The optical elements include a pinhole plate for restricting the size of the transmitted and reflected beams which plate, along with other of the optical elements, can produce unwanted reflections adding optical noise to the reflected beam from the target. A retardation plate between the pinhole plate and the target alters the polarization of the transmitted beam relative to the reflected beam so that a polarizer will discriminate between the true reflected beam signal and the unwanted reflections to thereby improve the signal-to-noise ratio at the photodete ctor.