Abstract: The instant invention is a method and apparatus for the measurement, with low uncertainty, of the six degrees of freedom of a first structure relative to a second structure. The apparatus is comprised of compact, rigid, thermally stable structures. The invention uses linear displacement transducers which have no active pointing to maintain a desired orientation of the linear displacement transducers with other parts of the measurement system.

Abstract: Apparatus and methodology by which the position, angular orientation, and departure of a moving body, such as a scanning head, can be measured with high accuracy with respect to a nominally straight line as the body translates along that line. Monolithic metrology and scanning heads with integrally formed metrology surfaces are provided and fabricated of preferably identical materials having low thermal coefficients and high temporal stability. Measuring systems operate in conjunction with the integral metrology surfaces to provide interferometric information by which the position and angular attitude of the moving body is constantly monitored. Calibration arrangements are provided for determining the absolute position and attitude of the moving body with respect to the metrology frame as the two move relative to one another so that any errors can be compensated with appropriate correction functions.

Abstract: A surgical lighting system including overhead surgical lights having integrating cavities which capture metal halide arc lamp optical energy and output spatially uniform optical energy to reflectors which direct the optic energy to a common surgical illumination region, a surgical light port system having illuminating ports, and a thermal dissipater. The surgical lighting system includes power back-up systems and light sources with multiple lamps that are automatically sequenced to provide constant surgical illumination.

Abstract: A scanning light source system combines the outputs from multiple, spatially separated, sequentially pulsed light sources for travel in rapid succession along one or more common delivery paths to provide one or more collective outputs that are comparatively higher than would otherwise be possible with the light sources operating singly.

Abstract: An optical sphere of nominal radius is positioned and supported within an assembly so that is can be activated with a predetermined motion with respect to an incoming converging spherical wavefront from an interferometer to calibrate the interferometer by determining the differences between the converging spherical wavefront and the reflected wavefront from portions of the area of the optical sphere as sampled thereover. The nominal optical sphere supported and sampled in this way mimics a “perfect” comparison sphere from which the systematic error of the interferometer wavefront may be determined. The optical sphere is preferably hollow and composed of Zerodur®. Internal magnets in conjunction with external induction coils provide motion control while the optical sphere is mounted on an air bearing for freedom of rotation and safety in transportation.

Abstract: The invention comprises methods and apparatus for reducing sub-harmonic cyclic errors by rotating by a small angle an interferometer or elements thereof. The rotation of the interferometer or selective elements thereof introduces a corresponding small angle between a sub-harmonic type spurious beam that subsequently interferes with either the reference or measurement beam so that the fringe contrast of the interference terms between the subharmonic spurious beam and either the reference or measurement beam is reduced by a required factor for a given use application thereby reducing nonlinearities in the phase signal.

Abstract: Interferometeric apparatus for analyzing the wavefront and intensity distribution of collimated beams from fiber optic collimators, lasers, and the like. The collimated beams are directed through a plate beamsplitter and combined with a well defined diverging, spherical reference beam preferably generated by a single mode fiber. Reference and test beams are directed through an optical assembly for changing magnification to selectively control lateral resolution at a detector plane. Phase shifting analysis is performed on the resultant interference patterns to analyze the wavefront, and intensity profile is determined as a separate step.

Abstract: Interferometric apparatus and methods for reducing the effects of coherent artifacts in interferometers. Fringe contrast in interferograms is preserved while coherent artifacts that would otherwise be present in the interferogram because of coherent superposition of unwanted radiation generated in the interferometer are suppressed. Use is made of illumination and interferogrammetric imaging architectures that generate individual interferograms of the selected characteristics of a test surface from the perspective of different off-axis locations of illumination in an interferometer and then combine them to preserve fringe contrast while at the same time arranging for artifacts to exist at different field locations so that their contribution in the combined interferogram is diluted.

Abstract: Apparatus and methodology by which the radius of curvature of individual optics may be determined through the interferometric measurement of the optical length of a spherical cavity established from null tests of combinations of the individual optics and an algorithm that mutually intercompares the measured cavity lengths and radii of curvature of the individual optics.

Abstract: Interferometric apparatus and methodology for monitoring the relative motion among objects, preferably that of mask and wafer stages in photolithographic processes. The apparatus comprises a plurality of interferometers with each operating to provide a mixed optical interference signal containing phase information indicative of the motion of a corresponding object. Electrical interference signals are generated from the optical interference signals, and one of these is modified to compensate for any Doppler shift differences among the electrical interference signals caused by differences in preferred relative rates of motion in the objects. A mixer receives the electrical interference signals and the modified electrical interference signal and generates an output electrical interference signal containing information about the relative motion between objects.

Abstract: An automated apparatus and method for measuring properties of optical components based on wavefront sensing and analysis. A wavefront of predetermined profile is directed at a surface to be measured so that it is more or less distorted in accordance with the shape of the surface and the distorted wavefront is sensed and analyzed. From the information derived from the distorted wavefront and other knowledge of the relationship between the surface and position of the wavefront of predetermined profile, the shape of the surface may be inferred along with other properties such as radius of curvature, focal length, conic constants, asphericity, toricity, tilt, and decentering. Concave, convex, cylindrical, and flat parts may be measured along with wavefront errors in bandpass transmitting components such as lenses, filters, and windows.

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 by comparing known and unknown spherical and aspherical shapes. Preferably, a spherical or partial spherical wavefront or reflecting surface is defined with respect to a known origin along a scanning axis. The test optic is aligned with respect the scanning axis and selectively moved along it relative to the known origin so that the spherical shape intersects the test optic at the apex of the aspherical shape and at radial positions where the spherical shape and the aspheric shape intersect at points of common tangency.

Abstract: Interferometric method(s) and apparatus for accurately measuring aspherical surfaces and transmitted wavefronts, particularly of the type having relatively large diameters and departure employed in lithographic applications used in the fabrication of integrated circuits and the like. An interferometer, preferably of the Fizeau type, is provided with at least one aspherical reference surface that is positioned adjacent the test optic. The test optic can be either rotationally or non-rotationally symmetric, a reflecting aspherical test surface, or a refracting system that is illuminated by an aspherical wavefront or produces a transmitted aspherical wavefront. In any case, the departure of the test optic from its intended performance is ultimately determined. The aspherical reference surface is illuminated by an aspherical wavefront provided by upstream optics structured so that the incident aspherical wavefront propagates normal to the aspherical reference surface across its entire surface.

Abstract: An electrical safety connector fuse for insertion into a two- or three-pin electrical socket comprises a sealed, tamper-proof housing having live and neutral apertures, and live and neutral receptacles for receiving the prongs of a plug, live and neutral prongs for insertion into the socket, and a fuse disposed within the housing. The connector fuse desirably has an internal light which lights up when the fuse is connected to a live socket, a blocking member or gate to prevent a user from receiving an electric shock by inserting objects into the live aperture of the fuse, and an insulting coating on at least a part of the live prong to prevent electric shocks as the fuse is inserted into a socket.

Abstract: An automated apparatus and method for measuring properties of optical components based on wavefront sensing and analysis. A wavefront of predetermined profile is directed at a surface to be measured so that it is more or less distorted in accordance with the shape of the surface and the distorted wavefront is sensed and analyzed. From the information derived from the distorted wavefront and other knowledge of the relationship between the surface and position of the wavefront of predetermined profile, the shape of the surface maybe inferred along with other properties such as radius of curvature, focal length, conic constants, asphericity, toricity, tilt, and decentering. Concave, convex, cylindrical, and flat parts may be measured along with wavefront errors in bandpass transmitting components such as lenses, filters, and windows.

Abstract: A method with a traceable calibration for reducing the uncertainty in the precision measurement of aspheric surfaces and wavefronts. A transmission sphere is mounted in an interferometer and its emergent wavefront is calibrated by comparing it to an optical sphere that is moved and sampled in a predetermined manner to make it act like a substantially “perfect” sphere mounted on a slideway. Afterwards, the calibrated wavefront from the transmission sphere is used to measure a spherical artifact mounted on the slideway to calibrate its surface. A transmission asphere is then mounted in the interferometer, and its emergent wavefront is calibrated by comparing it to the calibrated spherical artifact mounted on the slideway. The calibrated aspheric wavefront from the interferometer is then used to measure an aspherical artifact mounted on the slideway to determine is surface shape.

Abstract: Interferometric method and apparatus for measuring aspheric surfaces and wavefronts by directing a spherical wavefront of known design at a wavelength &lgr;1 at a reference sphere with known measured surface properties to generate a first electronic signal containing information about the optical path differences between the reference and measurement wavefronts generated an interferometer and directing an aspherical wavefront of known design at a wavelength &lgr;2 at an aspherical surface or wavefront to be tested to generate a second electronic signal containing information about the optical path differences between the reference and measurement wavefronts generated by the interferometer.

Abstract: Interferometric apparatus and methods by which aspheric surfaces and wavefronts may be precisely measured. The apparatus is provided with two modes of operation. In one mode, the apparatus is configured generally as a Fizeau interferometer in which an aspheric reference surface is used to permit the rapid, robust measurement of the difference between the aspheric reference surface and an aspheric test optic or wavefront. In another mode of operation, the aspheric test surface itself is completely characterized through in-situ use of an interferometric scanning technique using a spherical reference surface.

Abstract: Interferometric apparatus and methods by which the local surface characteristics of photolithographic mirrors or the like may be interferometrically measured in-situ to provide correction signals for enhanced distance and angular measurement accuracy. Surface characterizations along one or multiple datum lines in one or more directions may be made by measuring the angular changes in beams reflected off the surfaces during scanning operations to determine local slope and then integrating the slope to arrive at surface topology. The mirrors may be mounted either on the photolithographic stages or off the photolithographic stages on a reference frame.

Abstract: Interferometric apparatus and methods by which the local surface characteristics of photolithographic mirrors or the like may be interferometrically measured in-situ to provide correction signals for enhanced distance and angular measurement accuracy. Surface characterizations along one or multiple datum lines in one or more directions may be made by measuring the angular changes in beams reflected off the surfaces during scanning operations to determine local slope and then integrating the slope to arrive at surface topology. The mirrors may be mounted either on the photolithographic stages or off the photolithographic stages on a reference frame.