Abstract: Interferometric apparatus for measuring changes in altitude between a surface and a datum line where the apparatus comprises a dimensionally stable metrology frame and the datum line is defined in an object mounted for nominally plane translation with respect to the metrology frame in at least two orthogonal directions while experiencing relatively smaller changes in altitude in a direction nominally normal to at least two orthogonal directions. An elongated reflector is mounted with respect to either the metrology frame or the object to provide the surface, and at least one interferometer system is mounted at least in part on object for movement therewith.

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 method for interferometric measurement of a change in the relative directions of propagation of components of an optical beam, for interferometric measurement of a change in the direction of propagation of an optical beam, and for interferometric measurments of the change in orientation of an object. An interferometer is arranged to intercept light beams to produce an output beam from which a detector generates an electrical signal having a phase that varies in at least one plane in accordance with the angular separation between the beams. Electronic processing determines the phase and converts it to the angle separating the light beams.

Abstract: Apparatus and method for simultaneous interferometric measurements of angular orientation of and distance to a plane mirror measurement object using a multiple beam interferometer system. A first and second groups of the multiple beam interferometer systems have beams that contact the measurement object two times and three times, respectively, for simultaneous measurement of one or more of changes in the distance to and changes of the angular orientation in one plane or in two orthogonal planes of the measurement object.

Abstract: A method for making display products that generate special visual effects with autostereographic, dynamic, alternating, animated, and morphed images used in conjunction with lenticulated arrays for marketing and informational purposes. The special imaging effects, which can be integrated with discrete lenticulated container structures for data storage media and other contents, are achieved by digitally sampling and formatting source images with resampling procedures and then generating a merged image file that serves as the digital input for color printers or digital printing presses. The sampled images are printed on substrates along with registration lines or on preperforated stock preformatted for use with a corresponding lenticulated component. Afterwards, the images are separated from the substrate by either cutting them from the substrate using the printed registration lines as guides or breaking them out along the preperforated lines.

Abstract: An electrical outlet, used with a plug having live and neutral prongs of equal length, comprises support member having live and neutral apertures, and live and neutral receptacles for receiving the prongs. A blocking member lies between the support member and the receptacles, and moves between a closed position, in which it blocks the apertures, and an open position, it which it does not block these apertures, thus permitting the prongs to enter the receptacles. The blocking member is biased towards its closed position, but has a cam surface which contacts the entering neutral prong and moves the blocking member to its open position. The blocking member also has a recess so that, when the blocking member is in its closed position, a portion of the live prong can lie within the recess.

Abstract: Apparatus and methods particularly suitable for use in electro-optical metrology and other applications to measure and monitor the refractive index of a gas in a measurement path and/or the change in optical path length of the measurement path due to the gas while the refractive index of the gas may be fluctuating due to turbulence or the like and/or the physical length of the measuring path may be changing. More specifically, the invention employs electronic frequency processing to provide measurements of dispersion of the refractive index, the dispersion being substantially proportional to the density of the gas, and/or measurements of dispersion of the optical path length, the dispersion of the optical path length being related to the dispersion of the refractive index and the physical length of the measurement path.

Abstract: Apparatus and methods particularly suitable for use in electro-optical metrology and other applications to measure and monitor the refractive index of a gas in a measurement path and/or the change in optical path length of the measurement path due to the gas while the refractive index of the gas may be fluctuating due to turbulence or the like and/or the physical length of the measuring path may be changing. Apparatus and method for measuring effects of the refractive index of a gas in a measurement path wherein the phase redundancy is resolved for phase signals.

Abstract: Apparatus and methods particularly suitable for use in electro-optical metrology and other applications to measure and monitor the refractive index of a gas in a measurement path and/or the change in optical path length of the measurement path due to the gas while the refractive index of the gas may be fluctuating due to turbulence or the like and/or the physical length of the measuring path may be changing.

Abstract: An illumination system for illuminating an area within a room includes one or more light sources, preferably disposed outside the room, one or more lighting heads disposed within the room, one or more light pipes and/or fiber bundles to transmit light from the source(s) to the lighting head(s). The system includes means for controlling both the intensity and the color rendering index of the light emitted from the lighting head. In a preferred embodiment, the sources include an incandescent source extending across the visible spectrum and a light emitting diode source which emits essentially red light, and control of the color rendering index is effected by controlling the relative amounts of light from the two sources reaching the lighting head. Preferred forms of the invention also include special joints which permit all necessary translations and rotations of the lighting head while still permitting a continuous light path via fiber bundles and/or light pipes from the source to the lighting head.

Abstract: A process for measuring at least one parameter of an optical element having first and second surfaces on opposed sides thereof uses a reflection-reducing member, which is solid and has substantial mechanical integrity, but which is resilient and elastically deformable so as to conform to a surface with which it is placed in contact. This reflection-reducing member is contacted with the second surface of the optical element so that a surface of the reflection-reducing member conforms to this second surface, the parameter is measured, and the reflection-reducing member is removed from the second surface leaving this surface substantially free from any residue. The presence of the reflection-reducing member reduces or eliminates unwanted reflections from the second or “back” surface of the optical element, thus simplifying the measurement of any parameter which depends upon detecting reflection from the first or “front” surface of the optical element.

Abstract: A compact binoculars utilizing roof mirrors is disclosed. Compactness of the binoculars is achieved by maintaining the optical axis in the same plane as the axes of movement of the focusing apparatus and eyewidth adjustment apparatus. A method of manufacturing the roof mirror is also disclosed. The method allows produces and inexpensive and precisely aligned roof mirror for use in the compact binoculars.

Abstract: This invention relates to apparatus and methods for in-line testing for leaks in flexible containers traveling along a production line at high speeds. The apparatus inspects semi-rigid plastic containers at a high capacity by using multiple sensors at fixed displacements along a compression section while analyzing the response of the sensors such that internal pressure decays of leaky containers are readily discernible without interrupting the flow of the production line.

Abstract: Methods and apparatus that combine dispersion interferometry with refractometry to compensate for refractive index fluctuations in the measurement path of a dispersion interferometer over both short and long time periods. Dispersion and refractometry data are weighted over appropriate time intervals, and means and methods are also provided for initializing &Ggr;, the inverse dispersive power, so that the dispersion and refractometry data are self consistent. A refractometer is placed in close proximity to the measurement path of the dispersion interferometer to experience substantially the same air flow and act as a surrogate for obtaining information about the index of refraction.

Abstract: Apparatus and methods particularly suitable for use in electro-optical metrology and other applications to measure and monitor the refractive index of a gas in a measurement path and/or the change in optical path length of the measurement path due to the gas while the refractive index of the gas may be fluctuating due to turbulence or the like and/or the physical length of the measuring path may be changing. More specifically, the invention employs electronic frequency processing to provide measurements of dispersion of the refractive index, the dispersion being substantially proportional to the density of the gas, and/or measurements of dispersion of the optical path length, the dispersion of the optical path length being related to the dispersion of the refractive index and the physical length of the measurement path.

Abstract: The fluid tightness of containers having a first deformable section and a second deformable section spaced from the first deformable section is checked by changing the pressure applied to the first deformable section, preferably without causing fluid to flow through the first deformable section out of the container, and without changing the pressure applied to the second deformable section, thereby causing a deformation of the first deformable section and a change in pressure within the container; and thereafter monitoring a predetermined characteristic, preferably the position, of the second deformable section. This process can be used to check the fluid tightness of the containers with relatively fragile seals, for example, a foil lid of a food container without mechanical contact. Automated apparatus for carrying out this process is described.

Abstract: Displacement measuring interferometers (DMI) are disclosed for use in conjunction with apparatus for measuring and monitoring the intrinsic optical properties of the gas in the measurement leg of a DMI to compensate for variations in the refractive index of the gas that would otherwise render subsequent displacement calculations less accurate. The DMIs may be used for either linear or angular displacements. Cyclic error compensation, wavelength monitoring and correction, and phase redundancy features are included to further enhance the accuracy with which displacement determinations may be made and are particularly suitable for use in photolithographic applications.

Abstract: Apparatus and methods particularly suitable for use in electro-optical metrology and other applications to measure and monitor the refractive index of a gas in a measurement path and/or the change in optical path length of the measurement path due to the gas while the refractive index of the gas may be fluctuating due to turbulence or the like and/or the physical length of the measuring path may be changing. More specifically, the invention employs electronic frequency processing to provide measurements of dispersion of the refractive index, the dispersion being substantially proportional to the density of the gas, and/or measurements of dispersion of the optical path length, the dispersion of the optical path length being related to the dispersion of the refractive index and the physical length of the measurement path.

Abstract: A pressure-sensitive switch comprises a base member having a mounting surface formed of electrically-insulating material; two electrodes mounted on the base member and each having an electrically-conductive contact surface, and a flexible diaphragm having its periphery secured in a fluid-tight manner to the mounting surface with its electrically-conductive central portion overlying the contact surfaces of the electrodes. The diaphragm, which is formed with plural corrugations, is exposed to the external pressure. When the switch is exposed to atmospheric pressure, the central portion of the diaphragm does not touch the contact surfaces of said electrodes, but when the switch is exposed to a super-atmospheric pressure, this central portion is forced into contact with both contact surfaces, thus electrically connecting the two electrodes. This pressure-sensitive switch is especially useful for use with hydrophones, as in seismic streamer cables.

Abstract: At least one dimensional characteristic of a workpiece is measured, in situ, while at least one surface of the workpiece is subjected to a finishing operation. The measurements are obtained using an interferometer that generates interfering wavefronts reflected from the front and rear surfaces of the workpiece. Variations in the optical thickness of the workpiece can be determined from the resulting interferogram. The resulting optical thickness data can be used directly and/or combined with other pre-acquired data about the workpiece to obtain information concerning a desired dimensional characteristic of the workpiece. This dimensional characteristic may be transmitted wavefront error, work surface smoothness, and/or work surface profile. These measurements then can be used to terminate the finishing process at an optimal time and/or to control the operation of the surface-finishing machine.