Abstract: The holographic diffraction efficiencies of photorefractive or electro-optic crystals, such as bismuth silicon oxide (BSO), increase while experiencing high AC voltages. The diffraction efficiency also increases with frequency of the AC voltages up to a saturation frequency. These enhancements are attributed to the response times of the crystal and the superposition of internal electric fields. The enhanced diffraction efficiency assists in retentively recording information bearing holograms in electro-optic crystalline media.

Abstract: A threading attachment is provided in the tooling area of a multiple spindle machine tool, wherein the tap holder is rotated by a motor which has an infinitely variable speed within a given range and includes a first speed for advance movements to tap workpieces. This advance movement is provided by a motive power unit to move the tap holder in the advance movement and also in a retract movement at the completion of tapping. The motor has a second variable speed condition to back the tap out of the workpiece. This threading attachment is modular in construction to permit it to be physically mounted in any of the spindle positions of the multiple spindle machine tool and to be capable of being utilized with machine tools of different frame sizes. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.

Abstract: A photographic lens comprising four lens units, of which the first and second counting from front are of positive power, and the third and fourth have powers of opposite sign to each other, wherein as focusing is performed from infinitely distant object to nearby object, the first three units are axially moved in such differential relation that all the three air separations between the successive two units increase, while the fourth lens unit is held stationary during focusing, thereby the picture quality for the nearby object is greatly improved.

Abstract: A spatial frequency filter is adapted to an image sensor having a two-dimensional spatial frequency plane whose first quadrant includes a first prescribed point, whose second quadrant includes a second prescribed point, whose third quadrant includes a third prescribed point and whose fourth quadrant includes a fourth prescribed point. The two-dimensional spatial frequency plane has a vertical axis and a horizontal axis. The spatial frequency filter includes the combination of a primary filter part for providing a first trap line passing through the first prescribed point and a second trap line passing through the third prescribed point, a secondary filter part for providing a third trap line passing through the second prescribed point and a fourth trap line passing through the fourth prescribed point, and a tertiary filter part for providing a fifth trap line passing through the first and fourth prescribed points and a sixth trap line passing through the second and third prescribed points.

Abstract: A zoom lens comprising, from front to rear, a first lens unit of negative refractive power and a second lens unit of positive refractive power, in which either by moving the second lens unit forward to vary the magnification from the wide angle side to the telephoto side, a supplementary lens system is attached on the image side of the second lens unit in the middle of the course of varying the magnification or in the zooming position of the telephoto end side, or by moving at least the second lens unit forward, the supplementary lens system is attached, to change the focal length of the entire system.

Abstract: Methods and apparatus for improving contrast and resolution of a predetermined response of an object to illumination, render a two-dimensional array of light spots translatorily movable in a plane of the array, and scan the object by translatorily moving the two-dimensional array of light spots over the object. Sequential signals of light from the object scanned with that translatorily moving two-dimensional array of light spots may be viewed, or sequential reponses of the object to that translatorily moving two-dimensional array of light spots may be recorded or stored for subsequent reproduction and observation.

Abstract: A multifocal lens has an upper distance vision zone which is divided by a visible division from a distinct lower portion of the lens which includes an intermediate vision zone of progressively increasing dioptric power which leads into a near vision zone. The visible division is provided by an abrupt change in dioptric power in the range from about 0.5 dioptres to about 0.5 dioptres less than the difference between the constant dioptric powers of the near vision zone and the distance vision zone.

Abstract: A personal video viewing device is provided which allows the simultaneous viewing of a stereoscopic external image as well as a monoscopic electronic image. This is accomplished using two optical systems which share particular components. The relative intensity of both images may be adjusted using a three-iris system where each iris may be a mechanical diaphragm, an electronically controlled liquid crystal device, or a pair of polarized discs whose relative rotational orientation controls the transmissivity of the disc pair.

Abstract: A variable anamorphic lens system adaptable for use on an image recording instrument such as a camera (10). The system consists of an image transformation lens (14), a focusing lens (18) and an aperture stop (22). The transformation lens (14) and focusing lens (18) function together to form an image, on the camera's image plane (26), of a remote object at or near an object plane (30) as determined by the field of view. By manipulating the image transformation lens (14), the image of the remote object, or an insolated portion of the object, can be modified or transformed so that an altered image is formed on the image plane (26) of the camera (10).

Abstract: In a zoom lens a zoom operating ring is rotatable to vary the focal length of an optical system between a first focal length and a second focal length. A distance ring is rotatable to effect focusing of the optical system with respect to an object to be photographed which is positioned in a normal photographing distance range including infinity. A macro operating ring is rotatable to effect focusing of the optical system with respect to an object to be photographed which is positioned in a macro photographing distance range including an area of a shorter distance than a close distance in the normal photographing distance range. The optical system has a maximum magnification when the focal length is equal to the first focal length.

Abstract: An objective for an endoscope comprising, in the order from the object side, a first lens unit I having negative refractive power, a second lens unit II having positive refractive power, a third lens unit III having positive refractive power, an aperture stop S arranged between the front end of the second lens unit and rear end of the third lens unit and a fourth lens group IV comprising a lens component which has a concave surface on the object side, the four unit objective for an endoscope being arranged so that the overall length is short, outer diameter of the objective is small, angle of view is wide, intensity of light in the marginal portion is high, and distortion is corrected favourably.

Abstract: The present invention provides a gradient refractive index type anamorphic planar microlens which can be utilized for collimating an elliptical beam radiated from a semiconductor laser, or the like, and a method of producing such a lens. To collimate light rays, in which astigmatism exists, it is necessary to use a lens in which the respective focal distances in the directions perpendicular to an optical axis are different from each other. It includes a semiellipsoidal refractive index distribution region formed in a transparent substrate so as to have a major axis and a minor axis on a surface of the transparent substrate.

Abstract: An improved periscopic viewfinder for use following an afocal zoom section in a still electronic imaging camera. The viewfinder features an infrared detector for sensing scene intensity to provide strobe quenching information, visual displays, and a relay section comprising a symmetrical pair of new achromats for aberration control and field flattening purposes.

Abstract: When making a generally cylindrical article such as the barrel member of a lens barrel into a cylindrical molded article by the use of a resin material, a sandwich-molded article is formed by using a core layer resin material for the central layer of the molded article and surrounding the central layer by a skin layer resin material, the cylindrical molded article is a helicoid cylinder constituting the barrel, or a cylinder member provided with a toothed portion for receiving a drive force, or other barrel-constituting member, and the thickness of the skin layer resin material of the toothed portion of the helicoid cylinder or the barrel-constituting member is controlled.

Abstract: A multi-layered back reflecting mirror having a dielectric multi-layered coating on oen side of a glass or plastic transparent substrate which is further overlaid with a light-absorbing layer. The dielectric multi-layered coating is composed of four to eight dielectric layers laminated one on top of another having alternately differing refractive indices. At least one of these dielectric layers has an optical thickness of .lambda..sub.0 /2 (.lambda..sub.0 is the wavelength of light used as the reference measurement for design purposes) and each of the remaining dielectric layers has an optical thickness of .lambda..sub.0 /4. The mirror has a relative reflection minimum for visible light in the range of 480 to 550 nonometers.

Abstract: An optical gun sight having a central axis for a hand gun, shot gun and/or rifle having a firing axis and with the gun sight having an image erector system located generally at the focal plane of the gun sight and with the gun sight including adjustment means operative on the image erector system for selectively moving the image erector system in two tranverse directions which are in turn transverse to the central axis to provide calibration of the position of the image of the target relative to the firing axis of the hand gun, shot gun or rifle whereby compensation can be provided for the trajectory of the bullet to the target.

Abstract: For a durable, strong fixation of adjusted optical components by means of a self-hardening substance, the fixation is distributed over at least two mutually independent fixations and the parts used for the fixation are configured and dimensioned in such a manner that the resultant volumes or layer thicknesses of the self-hardening substance are optimal.

Abstract: An optical filter for use with an imaging lens in an incoherent imaging system operating in broadband illumination for increasing the depth-of-focus of the lens while maintaining energy thru-put is disclosed. The optical filter comprises a transparent support having on one surface thereof an array of transparent, discrete steps of substantially equal size, each step having a thickness that differs from all other steps by at least the coherence length of the radiation to be passed and the size of the array being equal to the size of the lens. In use, the optical filter is positioned in front of the imaging lens. When so positioned, the depth of focus of the imaging lens is proportional to the size of the individual steps rather than the size of the lens while the energy thru-put of the imaging remains the same as it would be without the optical filter.

Abstract: An article of manufacture, such as an electrically actuable light gate structure, includes a substrate which may comprise an electrooptically active solid-state light gate material. Spaced parallel electrodes are subdivided on that substrate into first and second electrode arrays alternating along an elongate region of the substrate. Individual terminals for the electrodes in each first electrode array are distributed along a line on one side of the elongate region, and individual terminals for the electrodes in each second electrode array are distributed along a line on the opposite side of the elongate region of the substrate. Any individual terminal of any one of the electrodes is spaced from the individual terminal of any other electrode by a center-to-center distance greater than the center-to-center spacing between that one electrode and the latter other electrode.

Abstract: A method of making a holographic optical element is disclosed. The method comprises the steps of determining the separation between interference pattern planes tangent to surfaces separated by a desired distance which achieves desired optical properties at a given first wavelength and angular orientation of light in a hologram disposed on a curved surface of first shape corresponding to the shape of a curved holographic element. The angular characteristics of exposure to achieve of this separation of planes in a planar analog of the desired curved holographic element is determined. The angles of exposure of interfering light rays to achieve this separation of planes in the planar analog by exposure of a sensitive substantially planar surface at a second wavelength in order to achieve the desired separation of planes and angular characteristics are determined.