Abstract: This invention is concerned with a thermal imaging optical system finding utility as an individual weapon sight. The system comprises an infra-red objective lens including a chopper blade together with front and back elements with an adjustable element therebetween. Infra-red radiation is received by the objective lens which also incorporates an internal substantially collimated plane polarized visible light source which illuminates a liquid crystal. The path of the infra-red and visible light which is directed to the liquid crystal cell, is repeatedly interrupted by the chopper blade. Changes in the liquid crystal cell due to the infra-red radiation transmitted by the objective lens are caused to modulate the plane polarized visible light transmitted through the liquid crystal cell to generate a visible image. This image passes through a relay inverting system and is detected by a visible light detector and viewed through an eyepiece.

Abstract: A mirror device for providing an image of a remote object, suitable for use in a multi-spectral collimator, comprises a primary concave mirror whose surface is an off-axis portion of a paraboloid having a rotational symetry about an axis, and a secondary concave mirror whose surface is an off-axis portion of a hyperboloid, one focus of which coincides with the focus of the paraboloid. The mirrors have sizes of the same order of magnitude. The primary mirror is so located that a light beam received by it and having a mean ray parallel to the axis of the paraboloid is unobscured by the secondary mirror. The radii of curvatures of the two mirrors at locations along their respective axes do not differ by more than 10%.

Abstract: A device for monitoring a patient in a medical examination apparatus has a support on which are mounted a television camera and a mirror sending on an image of a part of the patient to the camera, said support being movable with respect to the frame of the apparatus but fixed with respect to the patient.

Abstract: A solar radiation concentrator includes a supporting frame (1), facets (2) arranged thereupon in annular rows, the reflecting surface of the facets being divided into annular zones (3). At least one of the peripheral annular zones (3) has a toroidal surface whose generatrix (4) is an arc. The center (5) of curvature of the generatrix (4) lies to the other side from the concentrator optical axis (6) relative to the generatrix. The geometric parameters of the annular zone (3) having a toroidal surface are chosen in such a way that of all the beams falling thereupon parallel to the optical axis (6) of the concentrator two beams (7, 8) are focused to the projected focus (F).

Abstract: A boresight alignment verification device for testing sophisticated sighting and weapon systems used on various types of military aircraft and vehicles. The alignment device measures boresight error between a reference line of sight, a vehicle sighting system and a weapon system.

Abstract: Reflection holograms are described and are prepared from a transmission hologram. The reflection hologram is divided into a plurality of sequential parallel notional strips each of which is divided into bands, the bands and strips extending across the hologram from one side or end to the other and being parallel. Each band of a strip contains information derived from a respective notional strip into which the transmission hologram was divided during production of the reflection hologram. Thus each strip of the reflection hologram contains information derived from the whole of the transmission hologram. The reflection hologram is produced from the transmission hologram by a process in which each band of a notional strip of the reflection hologram is exposed in turn to a respective notional strip of the transmission hologram.

Abstract: A break-away mirror is provided with an extensible resilient tension member (26) coupled to the pivoted assembly (11) of the mirror (10) and also coupled to a head (21) on the outer end of a tilt control lever (19), the tension member extending into the pivoted assembly from the head, and being arranged to guide the head (21) back into its track (22) after it has been displaced therefrom by break-away or other forces.

Abstract: Eyeglass frames fabricated from shape-memory alloys which have optimized elastic properties, which exhibit a combination of shape-memory and elastic properties, which utilize the shape-memory property of these alloys in fastening elements or which utilize the flexibility and fatigue resistance of the martensite state of the alloys as a hinge element.

Abstract: An auxiliary external rearview mirror apparatus which is adapted to be mounted to existing external vehicle mirrors of substantially any size or shape to provide the driver or other occupant of the vehicle with an enhanced view of the roadway. The auxiliary external mirror apparatus comprises an auxiliary mirror member, first and second support arms for mounting the auxiliary mirror member to an existing external mirror member of a vehicle, and securing means adapted to extend around the back side of the existing mirror member from the first support arm to the second support arm to secure the auxiliary mirror apparatus to the existing mirror member without covering the existing mirror to any significant extent. The auxiliary mirror apparatus is of streamlined shape and extends from the existing mirror member along substantially the same line that the existing mirror member extends from the vehicle.

Abstract: The total transmissibility optical system or lens is an assembly of curved members or mirrors arranged such that a beam of radiation will reflect through the apparatus and come to a focus on an opposite side. An inner member, comprised of a pair of conical reflectors joined at their respective bases, is disposed within an outer member such that their axes are parallel to the radiation beam. The outer member is comprised of a first inner reflective surface in the shape of a hollow segment of a paraboloid of revolution and a second inner reflective surface in the shape of a hollow truncated cone. The two inner reflective surfaces of the outer member are also joined at their respective bases. The mirrors are made of a highly polished metal which will reflect any type of radiation beam, such as infrared radiation as in a night vision device. The lens can be used in harsh environments, such as an irradiated environment, since the lens will not be affected thereby as will a glass lens.

Abstract: The invention features an optical system for removing electromagnetic interference components from a radio frequency signal. The radio frequency signal is electrically cascaded through a series of multiple channels each having a common pathway. The final RF output of the system produces a notched signal whose notch depth is the cumulative depth of each channel notch depth.

Abstract: An automated visual testing system is disclosed which presents an alternating steady state visual stimulus to a patient through an optical system that modifies the stimulus image. As the image changes, the patient produces evoked potentials that change. The evoked potentials are detected by a product detector which produces the amplitude of the evoked potentials. The amplitude is monitored through an analog to digital converter by a supervisor computer. The supervisor computer produces patient response curves from which it diagnoses visual system malfunction and/or prescribes correction. A control processor controls a stimulus generator to produce the image and an optical system, that includes polarizers, an astigmatism test slit or a cylindrical lense, a zoom lense system and a variable focal length test lense, transmits the image to the patient. The steady state visual potential stimulus generator is a device by which a rapidly complementing or flashing pattern can be presented to the patient.

Abstract: A method and system for generating a dynamic, real time synchronized display of individual visual fixation points of one or more viewers superimposed on a video taped visual presentation for subsequent evaluation to assess the effectiveness of such visual presentation in communicating information.

Abstract: An eye movement tracker for stabilizing in two dimensions a diagnostic, treatment or other ophthalmic illumination on the fundus has a laser source which produces a narrow directed tracking beam, an optical steering assembly for controllably directing the beam to illuminate a region of the fundus, and an optical imaging assembly for imaging the illuminated region on a spatially-distributed photodetecting element. A tracking circuit scans the detecting element to detect motion of a spatially variant intensity feature and controls the optical steering assembly to redirect the optical path and maintain the feature in a fixed position. This repositions the diagnostic or other illumination, maintaining it in a fixed position on the fundus during eye movement. Scanning rates many times those of conventional systems are achieved, effectively stabilizing even very rapid eye movements. A viewing port provides an operator with a 30 degree field of the subject's eye fundus.

Abstract: The invention relates to an ophthalmoscope for indirect ophthalmoscopy. The device contains a light source, a vertically movable condenser and a mirror--preferably--vertically movable.A lens carrier including a set of lenses can be affixed at will to the ophthalmoscope.

Abstract: A roll is provided comprising a rotating hollow roll forming a working circumference and having a stationary crosshead extending therethrough to form a clearance gap therebetween. The entire clearance gap is filled with pressurized fluid. In the crosshead cylinder-like bores are provided with piston-like sealing elements displaceable therein to rest against the inner circumference of the hollow roll. The elements optionally may exert against the inner circumference of the hollow roll a higher or lower pressure relative to the pressure in the gap to create a line pressure or lifting force for shifting the hollow roll in the effective plane.

Abstract: Device for sharpening knives and other edge tools comprises an elongate abrasive honing element, typically a rotatably driven cylindrical rod formed of or coated with an abrasive and located in a housing so as to leave only a semi-diameter of the periphery exposed, the housing including sloping guide cheeks extending upwards at each end of the exposed part of the rod to determine the angle of the blade or other workpiece during at least a final part of its passage along the rod surface.

Abstract: A photographic imaging system for use in a stereoscopic camera or in a conventional camera for producing stereographs, comprising a beam splitter having two pairs of reflective surfaces each pair of reflective surfaces being disposed so as to direct an image through lenses so that two images are projected side-by-side onto a film, the film after being processed producing two prints or slides disposed side-by-side which can be viewed through a viewer to give a stereoscopic reproduction of the object photographed.

Abstract: The invention provides a display device with dissociable structure, making t possible for a user to observe a synthetic light image superimposed in his natural field of vision, said device being formed as two dissociable modules, namely: an image generating module having, inside a case, at least one part of the image generating members and a removable optical module including a support element to which is fixed a curved mixer type optical mount including, in a dihedral configuration, a flat semitransparent mirror and a curved semitransparent mirror.

Abstract: A method for testing the visual system to detect the presence of disease, and to distinguish disease which has degraded the linear visual pathway from disease degrading the nonlinear visual pathway in a manner which is substantially independent of the stimulus applied to the eye and the connection of the instrumentation to the patient being tested. Three light sources having their amplitude varied at different frequencies stimulate the eye. The response evoked in the brain is detected and Fourier analyzed. The amplitude of selected Fourier components are detected and used to compute a ratio which removes the dependence upon the factors stated above. The Fourier component amplitude factors are selected so that the number of factors in the numerator of the ratio is equal to the number in the denominator and the sum of the orders of the factors in the numerator are equal to the sum of the orders in the denominator.