Abstract: An objective particularly designed for copying machines consists of a biconvex lens air-spaced from a negative-meniscus lens with silvered convex surface, known as a Mangin mirror.

Abstract: A zoom lens system wherein the distance between the rearmost lens surface in the afocal zooming lens portion and the foremost lens surface in the image forming lens system is kept unchanged and an afocal magnification varying lens is inserted into the above described distance so as to enlarge the telefoto range, the magnification varying lens consisting of a front convergent lens group and a rear divergent lens group. The requirements for the magnification varying lens are so set that compensation for aberrations is kept in superior condition when zooming is effected by the lens system with the magnification varying lens being eliminated therefrom, while, when zooming is effected under the condition the magnification varying lens is added to the lens system, the aberrations are also well compensated for.

Abstract: A four element lens system for use on a camera and the like comprises two positive meniscus lens having two negative meniscus lens interposed between the positive lens. The optical axis of each lens elements being aligned with an aperture stopper element or its functional equivalent between the negative lens elements. The position of the effective plane of the aperture stopper satisfying the following equation: ##EQU1## wherein S is a distance along the optical axis between lens elements, S'.sub.2, is the distance between the surface of the second negative meniscus lens and the effective plane of the aperture stopper and S".sub.2 is the distance between the effective plane of the aperture stopper and the surface of the third negative meniscus lens. Preferably each of the lens elements is injection molded from a plastic material with both of the positive lens elements and the negative lens elements being identical lens.

Abstract: A Fabry-Perot interferometer includes a plane mirror and a confocal interferometer tandemly aligned so that the output of the former is applied as an input to the latter. Signals are derived for synchronizing the two interferometers by stopping the scan of the plane mirror unit during a portion of each scan cycle and incrementally advancing the scan position of the scan mirror of the confocal unit so that the confocal unit scans the plane mirror unit in a plurality of successive scans.

Abstract: A miniature and large aperture superwide-angle lens whose aberration is satisfactorily corrected consisting of ten lenses grouped in nine lens components wherein the following conditions (1) to (6) are satisfied:1. F/1.25 <.vertline.F.sub.1.2.3.4 .vertline.<F, F.sub.1.2.3.4 <02. f/0.8 <.vertline.f.sub.1.2.3.4.5.6.7 .vertline.<f/0.5, f.sub.1.2.3.4.5.6.7 <03. .nu..sub.5 < 30, .nu..sub.7 < 274. 2.3f < r.sub.13 < 3.0F5. 1.3f < (d.sub.9 + d.sub.10 + d.sub.11 + 22 d.sub.12) < 1.7F6. 0.6f < (d.sub.13 + d.sub.14 + d.sub.15 + d.sub.16 + d.sub.17 + d.sub.18) < 0.

Abstract: Method and apparatus for monitoring the vibratory displacements of a diffusing or reflecting solid body which in a preferred application is a turbine blade. A laser source of rectilinearly polarized monochromatic light provides a laser beam which is directed at the solid body. The beam reflected off the body is directed toward a first photocell with a photomultiplier along with part of the incident laser beam. Part of the reflected beam is directed toward a second photocell with a photomultiplier. A Kerr or Pockels cell varies the intensity of the laser beam in response to the output current strength from the second photocell to maintain the lighting of the first photocell constant regardless of the presence of speckle phenomenon. Apertures are arranged in front of the photocells and sufficiently small, e.g. one tenth the diameter of the grains of materials of the solid body, so that the lighting of the first photocell may be considered constant at all points.

Abstract: An apparatus for determining rotation of an area including optical apparatus for optically circumscribing the area and to guide laser radiation counter-directionally around the circumscribed area. Differences that develop between the clockwise and counterclockwise laser radiation as a function of the rotation of the area are detected to determine the rotation of the area. The optical apparatus includes an optical fiber waveguide which may function as a laser cavity or a ring inferometer path. The ring inferometer may also be provided by at least three reflective surfaces.

Abstract: The present invention relates to an optical system for color reproduction with nearly an equal magnification factor consisting of the front lens group and the rear lens group. The front lens group and the rear lens group have a symmetrical form to each other with respect to the diaphragm as center of symmetry being provided between both lens groups. Between both lens groups, the filters corresponding to the three primary colors of the light are provided so as to be interchangeable.

Abstract: An enlarging lens system comprising a front lens group which comprises a first, second, third and fourth lens components and a rear lens group which comprises a fifth, sixth and seventh lens components in which the first and second lens components are positive meniscus lenses, the third lens component is a positive meniscus lens consisting of a single lens or cemented doublet lens, the fourth lens component is a negative meniscus lens consisting of a single lens or cemented doublet lens, the fifth lens component is a negative meniscus lens consisting of a single lens or cemented doublet lens, and the sixth and seventh lens components are positive meniscus lenses, said enlarging lens system satisfying the following conditions. ##EQU1## Said enlarging lens system has the aperture ratio of F/3.5 and field angle of 50.degree. and is arranged so that at image of good quality can be obtained over the whole field.

Abstract: An image forming optical system, such as a photographic objective lens assembly is provided with a movable optical element. The movable optical element is designed and mounted so that it can optically interact with the transmission rays of the optical system or permit the rays to pass unaffected. The optical element can be a filter capable of improving the image forming characteristics of target object image to provide an advantageous soft focus, for example, as a portrait lens system or to provide a soft defocussed image. The optical filter element can have a central region capable of passing the converging or diverging transmitted rays through the optical system substantially free of refraction and a peripheral region capable of decreasing the transmitted image point intensity of rays transmitted therethrough. The optical filter element can be movable along the optical axis within a predetermined range of movement.

Abstract: The present invention relates to a device to adjust the position of optics lens systems which are movable relative to each other, and is characterized in that the device is equipped with a plural number of cam grooves variable relative to each other to adjust the position, frames to support the optical elements composing said optic lens system and springs forcing said frames to always be engaged in said adjusting cam grooves, whereby the forcing springs present forcing forces to compensate the components along the directions to move said adjusting cam grooves of the forces given to said plural number of said adjusting cam grooves.

Abstract: A refractometric densitometer includes a first packing element and a first gasket disposed at one side of a glass element and a second packing element and a second gasket disposed at the other side of the glass element. A groove for passage of a reference material and a groove for passage of a sample are respectively formed in the first and second packing elements. An inlet pipe and an outlet pipe are formed in the first and second gaskets for passing the reference material or the sample to the grooves. The outlet pipe of the first gasket is connected to the inlet pipe of the second gasket. Multiple reflection is imparted to an incident light from the part of the glass element between the faced surfaces of the glass element contacting the first and second packing elements.

Abstract: An extremely wide angle or fish eye lens system is provided capable of compensating for lateral chromatic aberration, field curvature and astigmatism while providing an aperture ratio of F/4 for use with a compact single lens reflex camera. The fish eye lens system includes a first lens group of four lenses on the object side of a diaphragm and a second lens group of at least three lenses on the image side of the diaphragm. From the object to image side, the first lens group includes a pair of negative lenses, a cemented doublet and a positive fourth lens having a convex surface on the image side adjacent a concave surface of the cemented doublet. The second lens group includes a pair of cemented doublets as two of the three lenses.

Abstract: The disclosed invention relates to methods and apparatus for obtaining the dimension, position or angle of an object using a point on the object boundary surface to create a diffraction wave when illuminated by a laser beam or other source of electro-magnetic radiation. This diffraction wave is then analyzed to obtain information as to the position of the object point tangent to the laser beam or the angular orientation of the object boundary at said object point.

Abstract: A miniature and large aperture retrofocus wide-angle lens whose aberration is satisfactorily corrected composed of eight lens elements consisting of ten lenses and grouped in two groups of five lenses each wherein the following conditions (1) to (6) are satisfied: ##STR1##

Abstract: A three element varifocal lens system in which the front and back lens elements are stationary and the inner lens is shiftable from the telephoto to the wide angle position. The front lens is negative while the inner and back lenses are positive. The lens system has particular utility for infrared imaging systems.

Abstract: A retrofocus-type lens system of six lens component configuration satisfying the following conditions which is compact in size and for which aberrations are corrected favorably.1. 0.14f < d.sub.4 < 0.3f2. 0.25f < d.sub.5 < 0.5f3. 0.4f < d.sub.5 + d.sub.7 < 0.6f4. f < .SIGMA.d < 1.4f.

Abstract: The pitch of twisted threads are measured by illuminating the threads with monochromatic light, especially a laser, to throw on a receiving surface a diffraction image from which the pitch is evaluated, preferably automatically by optical scanning and computing.

Abstract: A method and device for use in detecting a precise focussing point, which comprises the steps of: placing a photoelectric element on an optical path or optical axis of a lens of a camera; converting the information of the precise focussing point for a photographic object into a frequency variation of an A. C. signal; feeding said signal having varying frequency to a highly sensitive frequency detector such as a resonance circuit, a tuned amplifier, or frequency-amplitude convertor having acute frequency characteristics; and detecting the precise focussing point with high sensitivity by means of the output thus obtained; whereby the aforesaid functions may be satisfactorily performed, irrespective of the variation in the luminance of the object and whereby the focus of the lens may be brought into precise conformity to the predetermined plane (i.e., the position corresponding to a film).

Abstract: Apparatus and method is disclosed for measuring refractive properties such as spherical power, cylindrical power, cylindrical axis, etc., which are potentially present in a sphero-cylindrical optical system. Relative movement is effected between an incident light beam and the optical system under test so as to cause the incident beam to effectively move about a pre-defined first locus in the plane of the optical system thereby producing a refracted light beam which moves correspondingly about a second locus in a subsequent plane parallel to the plane of the optical system.