Abstract: The invention pertains to a laser apparatus which includes a laser cavity containing a laser medium, such as methyl fluoride or formic acid, which has a characteristic wavelength in the far infrared region of the spectrum. The laser cavity has first and second opposing mirrors which also respectively serve as an input mirror for the pumping radiation and an output coupling mirror. The invention is an improved output coupler which serves as one of the first and second opposing mirrors. A metal layer having a multiplicity of apertures therein is provided. At least one layer of dielectric material is disposed over the metal layer. The dielectric material is selected to be substantially reflective of infrared radiation (at least 80% reflective) and substantially transmitting of far infrared radiation (at least 80% transmissive). The reflectivity of the output coupler to far infrared radiation is selected by choosing the aperture size and shape of the metal layer.

Abstract: An apparatus and method for generating a two-dimensional back-projected image of a slice of an object. In accordance with the invention there is provided a carrier means having a plurality of substantially parallel elongated projections thereon, each projection having an optical characteristic (transmissivity or reflectivity) representing the density characteristic of said slice of the object as measured at a particular relative rotational angle. Means are provided for imaging successive sinusoidal patterns on the carrier means, the successive sinusoidal patterns being imaged at a predetermined rate. Photodetector means are responsive to the imaged sinusoidal patterns. Finally, a display or recording means, synchronized at the predetermined rate, is responsive to the output of the photodetector for displaying the back-projected image.

Abstract: An apparatus for determining the position of a movable element or stylus which is movable in a data space. In accordance with the invention there are provided first and second spaced receivers, each receiver comprising a hollow shell of piezoelectric material, which may be cylindrical or spherical in shape, and resilient conductive means coupled across the inner and outer surfaces of the shell. Means are provided for periodically generating a source of sound waves for travel between the stylus and the first and second receivers. Timing means are coupled to the receivers and synchronized with the generation of the sound waves for measuring transit time of the sound waves between the source and receivers. Computing means are employed to determine the positional coordinates of the stylus in a desired coordinate system, such as rectangular coordinates. In an embodiment of the invention the first and second receivers have conductive mesh loaded within the shell and in contact with the inner surface of the shell.

Abstract: The invention pertains to a video display apparatus which includes a cathode ray tube having at least one electron gun and means for deriving a source of excitatory voltage signal representative of picture information. In accordance with the invention there is provided a system for stabilizing the display intensity attributable to the electron gun comprising means coupling the source of voltage signal to the gun for generating a stabilized current in the gun, the level of current in the gun being substantially independent of variations in the operating characteristics of the gun. In the preferred embodiment of the invention a test signal is periodically applied at a predetermined level to the gun. A sampler samples the beam current of the gun during the test signal and generates a correction signal in accordance with the sample value. The correction signal is applied to the electron gun so as to stabilize its reference current level.

Abstract: An apparatus for use in conjunction with a processing system of the type which receives an input video signal comprising successive scanlines, each of which consists of a blanking portion that includes timing signals followed by an active portion representative of color picture information. The processing system is of a type that has an inherent delay whereby the output thereof is a television video signal delayed with respect to the input video signal. The invention is directed to an apparatus for generating a revised output video signal having timing signals in synchronism with the input video. In accordance with the invention there is provided a means for generating blanking portions in synchronism with the blanking portions of the input video signal.

Abstract: A radiation guard suitable for use in conjunction with a diagnostic table and penetrable by the hands of an operator to facilitate moving or examining a patient positioned on a table. In accordance with the invention there is provided a supportive frame mountable at about an edge of the table so as to extend vertically from about the edge, the frame comprising at least a pair of spaced bars. A plurality of strips of flexible radiation shielding material are mounted across the bars in closely spaced relationship, the strips being mounted sufficiently close together to prevent substantial radiation leakage through the frame. The hands of an operator can be inserted between the adjacent strips to manually reposition or examine a patient while protecting most of the operator's body from substantial radiation.

Abstract: A ring for housing a disc of radiation measuring material comprising a band having a circular shape; a housing integral with the band and formed in a surface thereof, the housing comprising a hollow cylindrical section substantially normal the band surface and terminating in an inwardly disposed annular flange which defines a substantially circular aperture. In a preferred embodiment of the invention a retaining protrusion formed on the inside of the cylindrical section and spaced from the annular flange is provided to retain a plurality of discs mounted in the housing in layered fashion.

Abstract: Radiation shielding apparatus for use in conjunction with a pad on a table. The apparatus comprises a set of units, each unit comprising a pair of joined substantially flat orthogonal flaps. The flaps are formed of a radiation shielding material and are adapted for removable placement under the pad whereby one flap contacts the table and the other flap extends vertically from an edge thereof. In a preferred embodiment of the invention the set consists of five units that provide protection around three sides of a rectangular table. In this embodiment, two of the units are identical and have asymmetrical trapezoidal flaps, and two others of the units are also identical, but have trapezoidal flaps which are of reversed orientation with respect to the first-mentioned two units.

Abstract: A magnetic recording medium comprising a base having a coating thereon containing magnetic particles, and wherein the binder contains a vinyl terpolymer and a diisocyanate.

Abstract: The present invention is directed to an apparatus for automatically examining hardware items progressing along a track to detect their characteristics and automatically sort the items in accordance with their characteristics. In accordance with one embodiment of the invention there is provided a nut inspection apparatus for monitoring the height of nuts, the apparatus being adaptable to also determine if threading is present on the inner surface of the nuts. In this embodiment there is provided a ramp for carrying the nuts, the ramp having a slot which defines an inspection position. A laser beam is split into first and second beams and adjustable means are provided for directing the first beam transverse the ramp and over the slot at the inspection position, the means being adjustable to a predetermined position above the ramp. A first photodetector is provided for receiving the first beam in the absence of a nut of prescribed height at the inspection position.

Abstract: For use in ultrasound pulse-echo imaging and neurosurgery systems, a plano-concave lens of elliptical shape is positioned in front of a transducer for producing an extremely narrow ultrasonic beam, and at the same time provides a large aperture to maximize the ultrasound power output from the transducer and the capture angle of reflected echoes. The lens is preferably formed of plastic, selected from a wide variety of available plastics in accordance with desired acoustical properties for a given application, and is preferably bonded to a flat, disc-shaped transducer. By proper selection of the material used to construct the lens it is possible to produce the correct amount of transducer apodization.

Abstract: A ferroelectric surface wave transducer device comprising an unpoled ferroelectric substrate having a substantially sinusoidal poled region at a surface thereof. A metal plate electrode is disposed on the opposing surface of the substrate. In operation an A.C. voltage applied across the two electrodes gives rise to a surface elastic wave in the substrate. Also disclosed is a method of producing a surface wave transducer of the type described. A pair of interdigitated metal electrodes are applied to a surface of an unpoled ferroelectric substrate. A poling potential is applied between the electrodes, preferably while the substrate is heated. The interdigitated electrodes are then removed and a metal plate electrode is applied over the region where the interdigitated electrodes had been. Finally, another metal electrode is applied to the opposite surface of the substrate. In a preferred embodiment of the invention the interdigitated electrodes are in the form of a moveable fixture.

Abstract: A method and apparatus for investigating earth formations surrounding a borehole by injecting microwave electromagnetic energy into the formations and then taking measurements which relate to the propagation of such energy in the formations. In the preferred form of the invention, the injected microwave energy establishes a lateral wave which travels in the formations adjacent the interface between the mudcake and the formations. Energy signals from the lateral wave are received at first and second receiving locations. The phase difference between signals received at the first and second receiving locations is measured. Also measured is the relative attenuation as between signals received at the two receiving locations. The loss-corrected dielectric constant associated with the formations surrounding the area between the first and second receiving locations is then obtained by judiciously combining the phase and attenuation measurements.

Abstract: An apparatus and method for recognizing the occurrence of a command word from among input speech that may be continuous in form. In accordance with the invention, means are provided for generating feature signals which depend on the features of an input word being spoken. The feature signals are processed to determine the time interval of occurrence of a predetermined sequence of features. Also provided is a means for comparing the feature signals which occur during the determined time interval with a stored set of features that are expected to occur characteristically during the command word to determine the degree of correlation therebetween.