Abstract: The invention provides a high-magnification and high-NA objective having a long working distance, which is corrected for various aberrations, especially chromatic aberrations over a wide wavelength range and allowed to have an aligning pupil position without making much use of cemented lenses and anomalous dispersion glass. The objective comprises a first lens group G1 including a meniscus lens concave on the object side and having a positive power as a whole, two optical elements of the diffraction type (DOEs), and a second lens group G2 including at least one cemented lens, and satisfies the condition for ensuring the edge thickness of the front lens as well as either one of two conditions for making effective correction for longitudinal chromatic aberration and chromatic aberration of magnification.

Abstract: A focal plate for use in camera and a method of manufacturing the same are disclosed. The focal plate comprises an optical plate, a plurality of lens-like uneven portions regularly formed on the surface of the optical material, and a plurality of fine rugged portions formed on each uneven portion, and is manufactured by forming a pyramid or prism relief on a metal plate through mechanical working, subjecting it to an electroplating to form a honeycomb pattern composed of hexagonal lens faces containing fine rugged portions therein, and then transferring the honeycomb pattern onto a surface of an optical material.

Abstract: An armature, a method for producing the armature and a mold for molding the same are so configured that the coil pitch of each of phase coils is set to a value of 125% or less of the pole pitch, the gap between the respective phase coils of any one of layers is so disposed as to face the intenral space of each of the phase coils of the other layer being contact with that layer, and the registering face of the mold for molding the periphery of the armature is so formed as to be parallel with the axial direciton of the armature.

Abstract: An ultrasonic piezoelectric transducer and an ultrasonic actuator for performing enhanced elliptical vibration comprise a first laminated piezoelectric element having a first fixed end, a resonator mounted to the opposite end of the first laminated piezoelectric element, a second laminated piezoelectric element having one end thereof fixedly mounted to the resonator in a direction other than a vibrating direction of the first laminated piezoelectric element, and a load mass fixedly mounted to the opposite end of the second laminated piezoelectric element. This structure permits the enhanced elliptical vibration of the transducer to have a large, controllable amplitude.

Abstract: A lens retaining barrel includes a cylindrical part for radially positioning a lens and an abutment for positioning the lens in the direction of the optical axis of the lens. The cylindrical part has a multiplicity of protrusions uniformly and circumferentially spaced around the interior thereof such that a circle inscribed within the protrusions has the same diameter as the outer diameter of the lens and has its center coincident with the optical axis of the lens. The abutment extends radially inwardly a greater extent than the protrusions and has a multiplicity of seats uniformly and circumferentially spaced around the abutment for receiving the lens. The seats have tops defining an envelope extending in a direction orthogonal to the optical axis of the lens. The lens is retained in position by each protrusion of the cylindrical part and each top of the seats and is adhered to the lens retaining barrel by an adhesive.

Abstract: A mold for forming coreless armatures having an upper mold and a lower mold. The lower mold has a mold cavity for receiving a shaft capable of supporting windings of a coreless armature. An elastic ring plate is placed between the upper and lower molds and is adapted for being compressed therebetween. The elastic ring plate is further adapted to contact terminal ends of the windings as they extend outside of the mold cavity, and to seal said mold cavity with the terminal ends extending therefrom.

Abstract: A method of molding a glass optical element. A supporting member is disposed in contact with a receiving mold part. A gob of molten glass is placed on an end surface of the receiving mold part and pre-molded by spreading out in contact with the end surface so as to form a glass preform. The glass preform supported by the supporting member is then transported to a heating furnace and heated. The heated glass preform supported on the supporting member is then transported to a position between a pair of mold parts and press molded to form a molded optical element. The end surface of the receiving mold part has a shape corresponding to an optical surface of the molded optical element so that in the pre-molding step, the glass preform is formed having a bottom portion having the shape corresponding to the optical surface. An auxiliary mold part can be provided having a molding surface in opposing facing relation with the end surface of the receiving mold part.

Abstract: A gradient index optical element for use in optical lens such as a camera or microscope is disclosed. The optical element comprises at least one of first metal dopants selected from La, Zr, Sn, In, Y, Ge, Zn, Ba, Ca, As, Sr, Ga and Gd distributed in solvent with a slope, and at least one of second metal dopants selected from Nb, Ta, Ti, Bi, Pb, Sb, Zr, Sn, In, Y and Tl, which is distributed equally in the solvent so as to satisfy following equation as absolute amount;.vertline..DELTA.C.sub.f /.DELTA.C.sub.g .vertline..multidot.100.ltoreq.5wherein .DELTA.C.sub.g is a difference between maximum value and minimum value of equivalent value of metal oxides of the first metal doping and .DELTA.C.sub.f is a difference between maximum value and minimum value of equivalent value of metal oxides of the second metal doping.

Abstract: A holding device for holding an optical element to be ground is arranged such that pressure applied to a receiving face of the optical element on the holder base is made different in the radial direction in order to eliminate deformation, positional deviation or inclination of the optical element due to grinding resistances during grinding or due to high-pressure grinding. An elastic member is employed as an elastic member, or a receiving member capable of absorbing the positional deviation, the inclination, or the like of the optical element during grinding thereof is used.

Abstract: A gradient index optical element has at least one first metal dopant selected from the group consisting of La, Y, Ga, In, Ge, Sn, Zn, Zr, Ba, Ca, As, Sr, Gd and Be distributed at a concentration gradient in a glass medium. The concentration gradient of the first metal dopant defines a slope having a direction. At least one second metal dopant different from the first metal dopant and selected from the group consisting of Bi, Sb, Nb, Ti, Ta, Pb, Tl, Zr, In, Sn, Y, Ba, Ca and Sr is distributed at a concentration gradient in the glass medium. The concentration gradient of the second metal dopant defines a slope smaller than the slope of the concentration gradient of the first metal dopant. The slope of the concentration gradient of the second metal dopant is in the same direction as the slope of the concentration gradient of the first metal dopant.

Abstract: A wave front interferometer for determining the shape of a surface from interference fringes has a light source which projects a light beam through a beam splitter disposed in an optical path between the light source and an optical surface whose shape is to be determined. The beam splitter bends a phase conjugate wave to become incident on the optical surface and to be reflected as a reflected beam. A phase conjugate mirror disposed in the optical path receives the light beam along a beam path through the beam splitter and reflects the light beam as the phase conjugate wave. The phase conjugate mirror reflects the light beam back along the same beam path so that the distance of the focus point of the light beam reflected from the phase conjugate mirror increases as the distance between the light source and the beam splitter and/or the phase conjugate mirror increases, so that either a convex or concave surface having a large radius of curvature can be measured.

Abstract: An armature, a method for producing the armature and a mold for molding the same are so configured that the coil pitch of each of phase coils is set to a value of 125% or less of the pole pitch, the gap between the respective phase coils of any one of layers is so disposed as to face the intenral space of each of the phase coils of the other layer being contact with that layer, and the registering face of the mold for molding the periphery of the armature is so formed as to be parallel with the axial direction of the armature.

Abstract: A polishing work holder for supporting a lens to be polished for use in a lens polishing machine is disclosed. The work holder comprises a holder body rotatably supported by a housing and having a recess portion formed on a rotating shaft of one end face thereof and a suction hole opened at the end face, a lens receptacle having a hole communicated with the suction hole to suck and hold a lens at one end surface, a spherical body intervened between the recess portion of the holder body and the lens holder so as to contact the another end face and for carrying the lens receptacle tiltably and movably in the crossing direction to the axis of the holder body, a fitting ring secured to the holder body concentrically and loosely fitted onto an outer periphery face of the lens or an outer periphery face of the lens receptacle so as to limit the tilting of the lens and the moving in the diametrical direction, and a sealing member provided between the holder body and the receptacle at outside of the suction hole.

Abstract: A method of manufacturing distributed index optical elements is disclosed. The method comprises a step of preparing silica sol including at least one of metal dopants, a step of dipping, after subjecting the silica sol to a gelling treatment, the silica gel in an elute into which a part of metal constituents other than silicon including in the gel is selectively eluted, and a step of drying and sintering the silica gel.

Abstract: A method of manufacturing a gradient index optical element comprises preparing a sol using silicon alkoxide and an aqueous metal salt solution as a source of index-modifying cations. The sol is treated to obtain a wet gel. Metal salt from the wet gel is eluted by immersing the wet gel in a solvent to produce a concentration gradiation of the metal salt in the wet gel. The metal salt is fixed in the wet gel by immersing the wet gel in a solvent. The steps of eluting and fixing are repeated so that a gradient index optical element is produced having a large difference in refractive index between the outer periphery portion and the center of the gel.

Abstract: A method of manufacturing gradient index optical element comprises preparing a sol using silicon alkoxide and a metal alkoxide as a dopant source of index-modifying cations. The sol is treated to obtain a wet gel. Metal alkoxide from the wet gel is eluted by immersing the wet gel in a solvent to produce a concentration gradiation of the metal alkoxide in the wet gel, and the wet gel is then washed. The steps of eluting and washing are repeated so that a gradient index optical element is produced having a large difference in refractive index between the outer periphery portion and the center of the gel.

Abstract: In accordance with the present invention, the dopant within one gradient index optical element has two independent concentration distributions. Particularly to use the present invention to obtain a gradient index optical element having an excellent chromatic aberration correction ability, it is only needed to make such dopant distributions as shown in the previously stated Japanese Patent Application No. 280897/1989. However, as to the doping of a dopant into a porous body, there is a limit in the amount which can be doped. This is a disadvantage of the molecular stuffing method, but the reason for this is that the dopant must be supplied into the holes as a solution and it is largely restricted by the solubility of the dopant in the solvent. In addition, since the intra-hole fixing of the dopant depends on the solubility difference by temperature or that by solvent exchange, it is further restricted.

Abstract: Disclosed is an ultrasonic oscillator comprising piezoelectric elements and a resonator fixed thereto and having one or more inclined surfaces, elliptical oscillations being generated at the front end of the resonator. Also disclosed is an ultrasonic motor utilizing this oscillator and adapted to rotate a rotatably supported rotor by pressing it with an appropriate pressurizing force against the section where the elliptical oscillations are generated.

Abstract: A photo-magnetic (magneto-optic) recording device having recording medium in the form of a rotating magnetic disc having magnetic characteristics in a direction perpendicular to its surface has a pickup head (7) disposed on one side of the disc and movable radially of the disc to scan selected areas of the disc. On the side of the disc opposite to that on which the pickup head is located, there are provided a plurality of coils (8) generating a bias-magnetic field applied to the disc. The coils are disposed in overlapping arrangement with their centers disposed on a line extending radially of the disc. The coils are energized by electric circuitry which comprises means for sensing the position of the pickup head and energizing a respective coil located in position to apply a bias-magnetic to the area of the disc scanned by the pickup head.