Abstract: An eyeglass lens (ophthalmic lens) has in its upper section (far sight field) surface refraction values relative to far sight, and has in its lower section (near sight field) surface refraction values relative to near sight, and is divided into left and right sections by a line (main meridian), the points of which at least approximate geometric umbilical points (points of the same surface refraction value in the two main curvatures) in which a transition region (progression zone) is provided between the upper section and the lower section, in which the surface refraction values of the upper section change gradually into the surface refraction values of the lower section and in which all the lines of equal average refraction values of the upper section intersect the main meridian in the upper section and all the lines of the lower section intersect the main meridian in the lower section and all are extended on both ends to the periphery of the eyeglass lens.

Abstract: A zoom lens system is constructed of a focusing member, variator, compensator and an image-forming lens arranged on a common optical axis in this order with respect to incident light to function as a master lens. The image-forming lens is divided into an intrinsic exchangeable front part and a fixed rear part so that when the front part is substituted by an attachment lens. The range of variation of the equivalent focal length of the master lens can be shifted toward longer focal lengths without causing any change in the back focal distance as it is so required because of the fixed rear part of the image-forming lens with the constant back of photographic lens. The attachment lens is constructed from at least two lens groups axially spaced from each other, each of which is provided with a rearwardly concave negative meniscus-shaped air space to prevent the reduction of high grade imagery of the master lens which would be otherwise resulted by the above-identified substitution.

Abstract: The present invention relates to a wide angle zoom lens system having a high variation ratio and a zooming range between a wide angle and a semi-telescopic angle, with the zoom ratio being approximately 2.3 to 3.0 times. The present invention provides the wide variation especially at the wide angle portion of the zoom. The present invention comprises, in order from the object side, a first lens group I having a positive focal length f.sub.I, a second lens group II (also referred to as a first variator lens group) having a negative focal length f.sub.II, and a third lens group III (also referred to as a second variator lens group) having a positive focal length f.sub.III. The present invention may include a lens group III' having a positive focal length f.sub.III'. The lens group III' may be disposed along the optical axis either at the image side or at the object side of the third lens group III. The lens group III' is unmovable during zooming.

Abstract: A wide-angle retrofocus lens system comprises a first lens component comprising a positive meniscus lens having its convex surface on the object side, a second lens component comprising a negative meniscus lens having its convex surface on the object side, a third lens component comprising a positive cemented lens component of a positive lens and a negative lens, a fourth lens component comprising a negative lens, a fifth lens component comprising a positive meniscus lens having its convex surface on the image side, and a sixth lens component comprising a positive lens. The system is arranged to satisfy the predetermined conditions so that, despite the use of a small number of component lenses, the overall length of the system can be made short, the back focal length long and various aberrations are well-corrected over a wide angle of image field.

Abstract: Disclosed is an optical design for a variable focal length lens of large effective aperture which is focusable over an extended range including the "macro" range and is provided with a high degree of correction.

Abstract: A vernier tandem Fabry-Perot interferometer includes a first pair of plane mirrors forming a first interferometer and a second pair of plane mirrors forming a second interferometer which is receptive of the output signal of the first interferometer. One mirror of each pair is mounted on a common movable support in positions such that when the support is moved in a given direction the spacing between one pair of mirrors remains in the same ratio to the spacing between the other pair of mirrors as the original ratio between these spacings. With this ratio maintained constant, the system continues to exhibit a single pass band at frequencies of interest corresponding to different spacings between mirror pairs. A deformable parallelogram maintains mirror parallelism while a transducer provides mirror motions. Other features are also disclosed.

Abstract: A telephoto zoom lens comprises a variable power system and a relay lens system. The variable power system comprises a first group provided with a positive refracting power and capable of focusing by displacement along the optical axis, a second group provided with a negative refracting power and capable of continuously varying focal length by displacement along the optical axis and a third group provided with a positive refracting power and capable of maintaining the focal position constant regardless of the change in the focal length by displacement along the optical axis in cooperation with said second group, said system substantially constituting an afocal system to an infinite object.

Abstract: A semi-wide angle photographic lens having short overall length is disclosed comprising six lens elements grouped into five components. The fourth component is composed of negative and positive lenses cemented each other to have a positive resultant focal length. The lens system has an aperture ratio of 1:2.8 and a view angle of .+-.24.degree..

Abstract: A wide angle objective intended especially for visual and photographic examination of the fundus of the eye. Each of the separate lens elements which together make up the objective is so designed that one surface of the element provides the desired refractive power and the other surface of the same element is concentric with the locus of the pupil produced by the surface bearing the refractive power. Also, the objective is so designed that black points are arranged at the locus of the ghost reflections of the mirror conjugated with the pupil of the test subject which are produced in the objective, thereby suppressing disturbing reflections.

Abstract: This invention relates to an interferometric process, and particularly to a process for examining the planarity of surfaces.

Abstract: A wide-angle photographic camera lens system having a very short total length of 2.75 f and a back focal length of 1.33 f comprising a first positive meniscus lens, a second negative meniscus lens, a third positive thick lens, a fourth negative lens, a fifth positive meniscus lens and a sixth positive lens.

Abstract: A pancratic camera objective of varifocal ratio close to 5:1, and with a relative aperture varying between 1:1.2 in a wide-angle position and 1:1.5 in a telephoto position, has a pair of axially shiftable negative components bracketed by a pair of substantially fixed positive components. Its negative third component is more widely separated from its positive fourth component in the wide-angle position than in the telephoto position.

Abstract: A retrofocus type wide angle photographic lens is disclosed comprising eight lens elements grouped into eight lens components. The lens has an aperture ratio 1:2.5 and a viewing angle of 85.degree..

Abstract: A variable soft focus lens system particularly adapted for photography is disclosed. The lens system incorporates two lens groups, a first object side lens group having an image side, rearmost surface convex to the image side, and a second, image side lens group having an object side, foremost surface concave to the object side. An airspace separating the first and second lens group has a meniscus shape concave to the object side. A good quality soft tone image having undersirable aberrations well within tolerable limits, is attained by shifting at least the second lens group along the optical axis relative to the first lens group whereby the airspace separating the two lens groups and a spherical aberration of the entire lens system is varied. An image does not lose proper focus while the spherical aberration of the system is varied. The second lens group has a refractive power within specified limits in relation to the refractive power of the entire lens system.

Abstract: An improved compact high speed telephoto lens system of a modified Ernostar type is provided, having from the object to the image side of the lens system, a first lens of a positive meniscus shape, convex to the object side; a second lens of a positive meniscus shape, convex to the object side; a third lens of a negative meniscus shape, convex to the object side; a fourth lens of a negative meniscus shape, convex to the object side; and a fifth lens of a positive refractive power. The fourth lens can be a doublet in an alternative embodiment. A positive Petzval sum is provided to insure an appropriate field curvature while permitting the refractive index of the positive lenses to be sufficiently high to correct coma and astigmatism.

Abstract: A system for sensing the position of a laser writing beam is provided wherein at least two laser beams of unlike frequency are superimposed on the laser writing beam. The combined laser beams are simultaneously deflected in a common optical deflection system. Once deflected, the unlike frequency laser beams are separated from the writing laser beam and focused onto a diffraction grating. The position of the focused beams of unlike frequency on the diffraction grating corresponds to the position of the writing laser beam on the writing media. The focused laser beams of unlike frequency produce a traveling interference pattern on the grating and are diffracted by the grating into a plurality of beams. By sensing the frequency of at least one of the beams diffracted by the grating, the position and movement of the writing laser beam can be determined.

Abstract: An improved phase measuring method and apparatus for measuring the relative hase and amplitude of an applied optical signal beam at a number of points in a plane. The combination of the signal beam and a reference beam are simultaneously directed onto a pair of photodector arrays, the reference beam on one array being .pi./2 radians out of phase with the reference beam on the other array. Respective interference patterns are formed on the photodector arrays, points on the arrays are sampled, and the desired amplitude and phase of the signal beam at the sampling points is determined by a series of computational steps.

Abstract: The present invention relates to a Tessar form photographic lens consisting of four lenses in three components. The first component consists of a positive meniscus lens having a convex surface at the object side, the second component consists of a bi-concave lens, the third component consists of a positive lens composed of a negative lens and a positive lens cemented on each other. A diaphragm is arranged in front of the image facing surface of the third component. The diameter of the first component is larger than those of the second and the third component, while the second component is in edge contact with the third component.

Abstract: A microscope objective lens system which has a long working distance and wherein image plane is flat over a wide visual field and various aberrations are favorably corrected, and said lens system comprising a first negative meniscus lens component, a second positive lens component, a third positive cemented lens component, a fourth positive lens component and a fifth negative cemented lens component.

Abstract: A compact wide angle lens system for use in a camera having a range finder is provided. The lens system is of five-group, seven-element type comprising, consecutively from the object to the image side, a first lens group consisting of a negative meniscus single lens convex to the object side, a second lens group consisting of a positive doublet having a cementing surface concave to the object side, a third lens group consisting of a negative meniscus single lens concave to the object side, a fourth lens group consisting of a positive doublet, and a fifth lens group consisting of a negative meniscus single lens concave to the object side.