Abstract: Methods and apparatus that combine the techniques of reversal (or self-calibration) to provide a low spatial frequency measurement of a part shape, independent of systematic errors in the staging used to move the part and small aperture interferometry to provide high spatial frequency information on a large part. The low spatial frequency is used to establish the rigid body motions (e.g., tip, tilt, and piston for a plano object) to be applied to the individual sub-apertures of interferometric data in stitching them together to give a full map at high resolution of the whole part. No overlap between sub-apertures is required.

Abstract: An underwater communications method and apparatus is provided for demodulating communications signals while compensating for the effects of range rate, i.e., relative velocity between the nodes of the communication system. The method of the invention is implemented in the DSP of an underwater bi-directional acoustic modem and method comprises the steps of generating a communication signal with an acquisition component for providing an initial estimate of the range rate. The acquisition component preferably is with a nonlinear frequency modulated acquisition component, preferably in the form of a hyperbolic frequency modulated signal, for providing the initial estimate of the range rate. Following this, a second set of signals, preferably a set of single frequency tonals, is generated and acquired using the initial estimate of range rate to obtain a more precise estimate of range rate.

Abstract: Interferometric scanning method(s) and apparatus for measuring optics either having aspherical surfaces or that produce aspherical wavefronts. A test optic is aligned and moved with respect to a scanning axis relative to the origin of a known spherical wavefront that is generated with a reference surface to intersect the test optic at the apex of the aspherical surface and at radial zones where the spherical wavefront and the aspheric surface possess common tangents. The test surface is imaged onto a space resolving detector to form interferograms containing phase information about the differences in optical path length between the reference surface and the test surface while the axial distance which the test optic moves relative to the spherical reference surface is interferometrically measured. The deviation in the shape of the aspheric surface from its design in a direction normal to the aspheric surface is determined and reported.

Abstract: A telephone has a key pad with ten number keys arranged to dial the digits from 0 to 9 inclusive, each of these number keys being marked with a visual indicator denoting the digit which the number key is arranged to dial. The 1 and 9 number keys are provided with tactile indicators, distinguishable from one another by touch, so that a user can dial 911 by touch under conditions, such as in thick smoke or during a power failure, when the visual indicators on the keys are not readily distinguishable. The tactile indicators do not substantially obscure the visual indicators on the keys bearing the tactile indicators. An existing telephone may be retrofitted with the tactile indicators by providing two auxiliary members which can be secured to the 1 and 9 number keys, preferably with adhesive. Additional tactile indicators distinguishable by touch may be provided on other keys needed to dial 911 on cordless or cellular telephones, such as the on and send keys on such telephones.

Abstract: A data communications and underwater release management system for acquiring data from remote positively buoyant instrumentation packages moored underwater through the use of an intervening mechanical release coupled at one end to the buoyant instrumentation package and at the other to the mooring. A topside modem system provides bidirectional communication with an undersea modem commonly housed with the release to permit data generated from the instrumentation to be conveyed topside and/or send command signals to release the instrumentation package so that it can ascend to the surface for recovery, repair, or refitting. Power is supplied via an on-board battery whose energy level is monitored and directed when below a threshold value to operate only the mechanical release.

Abstract: A computer-based stroboscopic interferometric microscope system for measuring the topography of a microscopic vibratory object includes an interferometric microscope equipped with a multiple-color (e.g., LED) or white-light source, a mechanical scanning apparatus for varying the optical path difference between the vibratory object and a reference surface, a camera having a two-dimensional detector array, and digital signal processing apparatus for determining surface height from interference data. Interferograms for each of the detector image points in the field of view are generated simultaneously by scanning the object in a direction approximately perpendicular to the object surface illuminated stroboscopically while recording detector data in digital memory.

Abstract: The invention provides an LED lighting device and method that produces high intensity, spatially uniform, white light in the near and far fields in a reduced package size that does not significantly heat the surrounding environment, wherein the white light is produced by using a phosphor layer in conjunction with a single LED.

Abstract: A video observation system, useful for location of fish and other plant and animal life underwater, comprises a solid state imager having substantial sensitivity to infrared radiation; video signal generating means for generating a video signal corresponding to the image formed on the solid state imager; mounting means for mounting the solid state imager on a submersible portion of a watercraft; and a video display device arranged to display a visible image corresponding to the image formed on the solid state imager.

Abstract: A night vision apparatus comprises housing arrangement by which a user can place an eyepiece adjacent one eye, a solid state imager sensitive to infrared radiation, an infrared radiation generation means arranged to generate infrared radiation into the field of view of the solid state imager; and an image generator arranged to receive the output from the solid state imager and to generate a visible image representative of this output at a position visible to the eye of the user. Head-mounted and hand-held embodiments are provided.

Abstract: The invention uses optics and precision mechanisms to quantitatively assess the performance of medical endoscopes. By viewing standardized optical targets under well-controlled conditions, the optical quality of endoscopes can be easily determined in much the same fashion as getting one's eyes tested at the optometrist. The actual design, however, is much more complicated than your optometrist's eye chart and different types of endoscopes from different manufacturers require customization of the target geometry, the viewing distance, and the viewing angle. Also, there are several optical characteristics beyond image sharpness that need to be assessed, requiring other unique test geometries, including contrast, distortion, and vignetting. Clinically significant measurements are performed with simplicity and cost-effectiveness through the use of relatively inexpensive optical components and an embedded processor and graphical display system.

Abstract: Interferometer systems are described that comprise optical assemblies to measure multiple degrees of freedom of a stage mirror and the topography of a reflecting surface of a stage mirror represented by datum lines and datum lines with corresponding local rotations of the reflecting surface of the stage mirror about the datum lines with high lateral spatial resolution. The interferometer systems measure slopes of datum lines and local rotations of the reflecting surface about the datum lines using single pass interferometric measurements of angular changes of directions of beams reflected by the reflecting surfaces. Two or more datum lines on a reflecting surface with concomitant measures of local rotations may be used to characterize topographic features, and these may be measured in situ in a lithography tool or measured off line either before installation or after removal from a lithography tool.

Abstract: Interferometric apparatus and methods for assembling and measuring highly precise optical assemblies such as triple corner cubes, and the like. The apparatus and methods use one or more interferometers that can simultaneously measure the shape, orientation, and distance to one or more surfaces.

Abstract: Interferometric scanning method(s) and apparatus for measuring rotationally and non-rotationally symmetric test optics having spherical, mildly aspherical and multiple, mildly aspherical surfaces. At least a partial spherical wavefront is generated from a known origin along a scanning axis through the use of a spherical reference surface positioned along the scanning axis upstream of the known origin. A test optic is aligned with respect to the scanning axis and selectively moved along said scanning axis relative to the known origin so that the spherical wavefront intersects the test optic at the apex of the aspherical surface and at one or more radial positions where the spherical wavefront and the aspheric surface intersect at points of common tangency to generate interferograms containing phase information about the differences in optical path length between the center of the test optic and the one or more radial positions.

Abstract: A hot sprue bushing is provided for transporting plasticized material from an injection nozzle to a mold cavity while controlling the temperature of the plasticized material. The hot sprue bushing has an elongate body having an inlet end for receiving the plasticized material, an outlet end for discharging the material, and a through passage for transporting plasticized material therethrough. The body also has first and second surfaces on opposed sides of the through passage and electrical heating means disposed adjacent the first and second surfaces respectively, the electrical heating means extending along at least a major portion of the length of the elongate body. Finally, the bushing has retaining means for retaining the first and second electrical heating means adjacent the first and second surfaces respectively and in heat conducting relationship therewith.

Abstract: Interferometric apparatus and method for measuring changes in distance to an object are compensated for the presence of undesirable phase shifts in measurement beams that result from their interacting with non-polarization preserving optical elements in at least one interferometer measurement leg. Compensation is provided by phase plates, multi-order phase plates set at a predetermined angle with respect to beam components, coatings on reflecting surfaces, or a segmented phase plate at least part of which is rotated with respect to polarized beam components, and combinations thereof. Compensation is provided in interferometers having measurement legs folded with reflecting surfaces that cause relative phase shifts in propagating polarized beams because of non-normal incidence. Compensation is also provided in upward and downward looking interferometers for measuring altitude and changes in altitude to a surface such as a translating wafer stage of a photolithographic exposure apparatus.

Abstract: Interferometric apparatus and methodology for precisely measuring the shape of rotationally and non-rotationally symmetric optical surfaces comprising an illumination source with two wavelengths, a transmission flat with a reference surface, a basic optical system for producing a wavefront of predetermined shape, a compensation component having an aspheric wavefront shaping surface and an aspheric reference surface. The aspheric shaping surface modifies the predetermined wavefront so that it impinges on the aspheric reference surface with a shape substantially that same as that of aspheric reference surface. For a given aspheric reference surface, the radius or curvature and spacing of the aspheric shaping surface are optimized so that its aspheric departure is no larger than that of the aspheric reference surface. Precise alignment in six degrees of freedom is provided via feedback control.

Abstract: A telephone has a key pad with ten number keys arranged to dial the digits from 0 to 9 inclusive, each of these number keys being marked with a visual indicator denoting the digit which the number key is arranged to dial. The 1 and 9 number keys are provided with tactile indicators, distinguishable from one another by touch, so that a user can dial 911 by touch under conditions, such as in thick smoke or during a power failure, when the visual indicators on the keys are not readily distinguishable. The tactile indicators do not substantially obscure the visual indicators on the keys bearing the tactile indicators, and are not the Braille equivalents of these visual indicators. An existing telephone may be retrofitted with the tactile indicators by providing two auxiliary members which can be secured to the 1 and 9 number keys, preferably with adhesive.

Abstract: Apparatus and methods for in-line testing of the internal pressure of flexible containers traveling along a production line at high speeds. The apparatus inspects semi-rigid plastic and thin-walled liquid filled containers by analyzing the output from a load cell that indirectly measures the reaction force applied to a container through the intermediary of a load cell roller that, in turn, supports a flexible belt that directly contacts containers while moving them through an inspection station without interrupting the flow of the production line. Containers are contacted only by a flexible portion of a conveyor belt to minimize structural and aesthetic damage to them that might otherwise occur during the inspection process.

Abstract: Apparatus for measuring angular changes in the direction of travel of a light beam comprising at least one beam shearing assembly for separating, preferably orthogonally polarized, components of the light beam and introducing a lateral shear between them. An analyzer operates on the components to provide them with a common polarization state. A lens focuses the commonly polarized components of the light beam to a spot in a detector plane, and a detector operates to generate an electrical signal having a phase that varies in accordance with the angular change of the light beam in at least one plane. Electronic means receive the electrical signal, determines the phase therefrom, and converts the phase to the angular change in the direction of travel of the light beam.

Abstract: Interferometric scanning method(s) and apparatus for measuring rotationally and non-rotationally symmetric test optics either having aspherical surfaces or that produce aspherical wavefronts. A spherical or partial spherical wavefront is generated from a known origin along an optical axis. The test optic is aligned with respect the optical axis and selectively moved along it relative to the known origin so that the spherical wavefront intersects the test optic at the apex of the aspherical surface and at radial positions where the spherical wavefront and the aspheric surface intersect at points of common tangency.