Abstract: A laser ray projector and remote measuring device comprising at least two of these projectors, wherein the measuring device comprises two laser ray projectors servo-controlled in position. Each of them comprises a spindle rotating through 180.degree. in one direction and in another from a certain point and a head secured to this spindle and rotating through 90.degree. in one direction and in the other from an origin. This head carries a prism which receives in each projector a laser ray issuing from a single source whereby rotation of the spindle and of the head enables each ray to scan all the points of a hemisphere. A computer makes it possible to convert the angular coordinates into cartesian coordinates.

Abstract: An apparatus for measuring an optical characteristic, such as color, of an object having two edges comprises a support for the object, a stop member slideable but releasably secureable to the support in a variety of different positions allowing for variation of the position of the stop member in two dimensions, and an optical instrument for measuring the desired optical characteristic. In use, the two edges of the object to be tested are abutted against two stop surfaces on the stop member and the optical instrument lowered adjacent the object to determine the optical characteristic of a portion of the object beneath the instrument. A number of similar objects can be tested by abutting them in turn against the stop surfaces of the stop member.

Abstract: Readout signals of a dithered ring laser angular sensor are processed by a signal combining circuit which forms part of a closed-loop dither signal remover scheme. The output of the signal combining circuit is demodulated as a function of the dither applied to the ring laser sensor and subsequently utilized to control a correction signal. The signal combining circuit combines the readout signal and the correction signal to yield an output signal stripped of substantially any dither signal components.

Abstract: Reference patterns are disclosed which are designed particularly for the functions of evaluation and alignment of an optical instrument, such as a spectrum analyzer or an optical correlator employing a matched filter array as its memory. A preferred embodiment of the reference input pattern is binary and of simple geometry such that it can be easily fabricated and the Fourier transform and autocorrelation functions can be easily calculated. Two-dimensional spectral features and autocorrelation patterns for one particular input function have been derived in closed form and numerically evaluated. The Figures herein illustrate the symmetries in the multi-peaked distributions. Tables of relative intensities are disclosed and are useful in evaluating and comparing the performance of different coherent optical processing systems.

Abstract: The movement of a predetermined zone of a surface of a vibrating object is measured by separating a laser beam having a predetermined coherence length into a probe beam and a reference beam. The reference beam is then delayed relative to the probe beam by a predetermined time interval sufficient for the probe beam to travel through a predetermined distance at least corresponding to the coherence length, before being combined with the probe beam to form a combination beam. The combination beam is then subdivided into a plurality of substantially equal component beams each of which is conducted along a separate path to a location spaced from the predetermined zone substantially by one-half of the distance traveled by light in the predetermined time interval between the above location and the predetermined zone.

Abstract: A scanning interferometer that is capable of measuring the complete relative movement of up to 10 or more measurement sites on a test structure, to determine thermal distortion or expansion. The interferometer includes means for dividing a source beam into signal and reference beams, and an acousto-optic deflector for deflecting the signal beam in response to a control signal to produce a deflected signal beam. The control signal is generated such that deflected signal beams are sequentially directed to the different measurement sites. Reflection means at each measurement site reflects the deflected signal beam to produce a reflected signal beam. Each reflected signal beam is combined with the reference beam to produce an interference pattern, and a photodetector positioned in the interference pattern produces a fringe signal. Signal processing means are provided for periodically measuring the phase of the fringe signal for each deflected signal beam, to thereby measure the movement of each measurement site.

Abstract: A first birefringent material is positioned to receive an optical signal output from an optical source. A second birefringent material is positioned to receive the signal transmitted through the first birefringent material. The birefringence of the first birefringent material is modulated to produce a modulation in the phase difference between two polarizations propagated between the birefringent materials. A detector forms an electrical signal indicative of the phase shift produced by the first and second birefringent materials between a pair of orthogonal polarizations in the optical signal received by the first birefringent material. This phase shift is opposite to phase shifts caused by changes in the source wavelength. A feedback signal indicative of the hase shift caused by the crystals is fed back to the optical source to stabilize its frequency.

Abstract: A process and device for measuring and processing in real time the changes of level between two or more points in buildings, structures, machinery or the like, when interested by works of civil engineering, wherein a laser ray generated by a laser tube and rotated on a planar or conical surface hits one or more targets constituted by fixed or mobile photodetectors, said targets being placed in correspondence with said points. The signals generated by the targets are transferred to a computer to be processed and immediately read (FIG. 1).

Abstract: The present invention relates to optical fiber measuring systems comprising a light source, a modulator for modulating the amplitude of the light signal emitted by the light source at a modulation frequency, an optical connecting fiber, a resonant cavity, a phase detector and a phase comparator. According to the invention, a sensor which is sensitive to an ambient parameter is incorporated into the cavity such that a variation in the parameter causes a variatioin in the phase of the signal at the modulation frequency. The invention can be applied to measuring systems for use in a severe environment.

Abstract: The frequency of an optical signal output from an optical source is controlled while maintaining the polarization of the signal by guiding the signal with either a polarization maintaining optical fiber or an integrated optics waveguide. A portion of the signal output from the light source is input to the light guiding structure. The optical signals are phase modulated, and an electrical signal indicative of the intensity of an optical signal output from the polarization maintaining light guiding device is applied to the optical source for controlling the frequency of the optical signal output therefrom.

Abstract: In a monolithic gyro assembly having three ring laser gyroscopes each measuring the inertial rotation of an axis, a polyhedron having three facets is used as the beam combiner for the gyroscope. On one of the facets is mounted a fringe detector for providing inertial rotation information for the gyroscope. On the remaining two facets, on either side of the fringe detector facet, are mounted beam power monitoring diodes for measuring the power of the light intensity of the respective beams. The directly measured power from the beams is then used to move a piezoelectric transducer to maintain constant pathlengths for the gyroscope.

Abstract: A feedback method, or automatic gain control circuit, for an image photosensor at the focal plane of an optical system for very narrow linewidth measurements of images having varying intensities such as fluorescing photoresist coated lines. The feedback method includes the steps of measuring the instantaneous intensities of the entire optical beam of radiation with a photodetector and applying the output therefrom to the photosensor to thus normalize its output signal.

Abstract: The design of a long-trace surface profiler for the non-contact measurement of surface profile, slope error and curvature on cylindrical synchrotron radiation (SR) mirrors. The optical system is based upon the concept of a pencil-beam interferometer with an inherent large depth-of-field. The key feature of the optical system is the zero-path-difference beam splitter, which separates the laser beam into two colinear, variable-separation probe beams. A linear array detector is used to record the interference fringe in the image, and analysis of the fringe location as a function of scan position allows one to reconstruct the surface profile. The optical head is mounted on an air bearing slide with the capability to measure long aspheric optics, typical of those encountered in SR applications. A novel feature of the optical system is the use of a transverse "outrigger" beam which provides information on the relative alignment of the scan axis to the cylinder optic symmetry axis.

Abstract: An improved thruster for propelling borescopes by the reaction forces generated by pressurized fluid expelled from the thruster has a desirably small cross-sectional profile made possible by its novel construction. The basic embodiment of the thruster comprises an elongated hollow cylinder sealed at one end by a bulkhead and supplied with pressurized fluid at the opposite, open end. A thin slot cut through the cylinder wall permits pressurized fluid to exit the hollow interior space of the cylinder, producing a reaction force useful in propelling a borescope tip to which the thruster is fastenable.

Abstract: A fiber optic rotation sensor using birefringent optical fiber includes an uncorrelating element, an equalizing element and a polarizer in the common input and output fiber portions of the sensor to reduce or eliminate the intensity type phase errors caused by interference between lightwaves originally in the same polarization mode on entry to the sensor loop that cross couple into another polarization mode. In the preferred embodiment, the uncorrelating element comprises a birefringence modulator and a length of birefringent fiber. The equalizing element comprises a birefringent fiber having a splice at which the axes of birefringence of the spliced portions of the fiber are positioned at 45.degree. relative to each other.

Abstract: An endoscope comprising an elongated insertable part, a rigid tip body provided in the tip part of the insertable part and having an observing window and illuminating window, an observing means for observing an object to be imaged by receiving a light from the object incident from the observing window and an illuminating means emitting an illuminating light from the illuminating window, wherein the insertable part has a removably fitted tubular outer cover covering the outer periphery of this insertable part, an annular fixing member fixing the outer cover in the tip part to the tip body is secured to the outer periphery of the tip body and has a slit provided in the axial direction and further a cuttable connecting part connecting the slit in the direction intersecting the axial direction is provided.

Abstract: The optical aiming device may be mounted on firearms. It comprises a light-collecting rod (8) consisting of a phosphor material to illuminate a central circular spot (22) of an aiming mark (6). Such illumination passes through a truncated hollow cone (25) and is used for good ambient light conditions. For poor ambient light four tritium luminous cells (18, 19, 20, 21) are mounted around the truncated hollow cone (25). Each tritrium cell illuminates one radial line component (23) of the aiming mark (6) via the external mirrored lateral area of cone (25). To adapt the brightness of the aiming mark to the brightness of the target the tritium luminous cells (18, 19, 20, 21) may be shifted on a circle around cone (25) with respect to the line components (23) of aiming mark (6).

Abstract: Substrate inspection apparatus and methods, and illumination apparatus. The inspection apparatus and method includes memory for storing the desired features of the surface of the substrate, focussed illuminator for substantially uniformly illuminating a region of the surface of the substrate to be inspected. Additionally there is a sensor for imaging the region of the substrate illuminated by the illuminator, and a comparator responsive to the memory and sensor for comparing the imaged region of the substrate with the stored desired features of the substrate. The illumination apparatus is designed to provide substantially uniform focussed illumination along a narrow linear region. This apparatus includes first, second and third reflectors elliptically cylindrical in shape, each with its long axis substantially parallel to the long axes of each of the others.

Abstract: An apparatus and method of determining gyro het phase and acceleration at turnaround using the digitized heterodyne signals. A digital design that incorporates the necessary logic and is integrated into a gyro unit. An integer algorithm that processes the turnaround data to produce a phase correction that can be added to the gyroscope count. Separation of high speed data processing from lower rate data to simplify the code and permit evaluation of turnaround correction performance.

Abstract: A laser light inspection device for inspecting opposite surfaces of a workpiece with a low angle laser light beam. The laser light beam is directed in successive scans of a first and second sides in a repetitive manner using a pair of dividing mirrors and a pair of low angle mirrors. Light reflected by any debris back toward the direction of origin of the light beam is collected and analyzed.