Abstract: A zoom lens system which provides magnification factors in the range of 12 to 24. The lens system of the invention is particularly useful in micrographic reader/printers.

Abstract: A lens for use in optical disc players comprising a single biconvex element having both surfaces aspheric. The refractive index, N.sub.D, of the element at 589.3 nm is 1.492 and at the same wavelength the Abbe V number is 57.4. At 800 nm the refractive index, N.sub.800, of the element is 1.48584. Each surface may be described by the equation: ##EQU1## wherein: X is the sag of the aspheric surface from a plane reference surface at a radial distance Y from the axis of the lens.______________________________________ Surface 1 Surface 2 ______________________________________ C = 0.354021 -0.1557360 K = 0.0 -20.4938239 D = -0.2909441 .times. 10.sup.-2 0.0 E = -0.5163209 .times. 10.sup.-3 0.0 F = 0.5075886 .times. 10.sup.-4 0.0 G = -0.1399892 .times. 10.sup.-4 0.

Abstract: A lens device for a photographic printer to enable it to print same size prints from full-frame and half-frame images intermixed in an elongate strip of spliced film strips. The lens device rotates the image through 90.degree. without affecting the inversion needed in a printer lens. The device includes a pechan prism in each of the air spaces between the lens elements and the object and image planes, respectively. There is a relative angular displacement of 45.degree. between the prisms.

Abstract: A rear attachment lens mounted between a master lens and an image plane for increasing the composite focal length. It consists of four lenses. The first lens is negative and has a concave surface on the image side. The second lens is positive, convex on both sides and cemented to the first lens. The third lens is negative and is concave towards the master lens. The fourth lens is positive, convex towards the master lens and has at least one aspherical surface. Preferably five numerical conditions on magnification, refractive indices, radius of curvature and asphericity are satisfied.

Abstract: A gas lens 10 for lensing a light beam 12. A first gas is injected through orifices 18-18.sup.n into enclosure 16 thereby forming a row of jets 14-14.sup.n. A second gas having a different index of refractivity than the first gas also is contained within the enclosure 16 in the form of a mantle 24 surrounding each jet 14-14.sup.n. The light beam 12 is lensed (either convergently or divergently) as it passes through the jet/mantle interfaces.

Abstract: Optical systems for use with attachments for a conventional reflex motion picture camera to permit stereographic cinematography are disclosed. The optical systems include lens systems having four powered elements having negative, positive, negative, and positive focal lengths respectively. The lens systems are adapted to be used with the Bernier stereographic cinematography attachment system as modified for reflex motion cameras. The lens systems include a normal lens system, a wide angle lens system, and a telephoto lens system. The wide angle lens system further includes plane parallel refractive elements to increase its overall length without changing its back focal length, and the telephoto lens system is adapted to be used with internal displacement prisms which bring the images produced by the telephoto lens system into the camera flange opening.

Abstract: For manufacturing monaspherical lenses, a correction layer of a synthetic resin is provided on a substrate having a spherical surface. In this method, centering is performed by using the curvature of the surface of the matrix. With a correct choice of the radius of curvature of the substrate surface, the substrate approaches the matrix most closely near a collection of inflection points in the matrix surface situated on a circle. A good centering without a guiding mechanism is possible by using the method according to the invention. Moreover, the differences in thickness in the correction layer are small enough to prevent shrinkage defects upon curing of the synthetic resin layer.

Abstract: A copying lens having a wide angle of view is of a six-component, eighth-element configuration which is completely symmetrical with respect to an aperture stop. The first component is composed of a convex-meniscus lens having a convex surface directed toward the object side, and the second component is composed of a concave-meniscus lens having a convex surface directed toward the object side. The third component is composed of a double-convex lens and a double-concave lens which are joined to each other, with the double-convex lens being closer to the object side. The fourth, fifth, and sixth components are substantially same as the third, second, and first components. The fourth and third components, the fifth and second groups, and the sixth and first components are symmetrical with respect to the aperture stop. The copying lens meets the following conditions:(i) 0.45<f/f.sub.1.2 <0.6;(ii) 0.1<f/f.sub.3.4 <0.25(iii) 0.1<n.sub.4 -n.sub.3 <0.3;(iv) 15<.nu..sub.3 -.nu..sub.

Abstract: A copying zoom lens system consisting of five lens elements. The first and fifth lens elements are each a single negative lens element with a negative focal length. The middle three lens elements are grouped into a central lens unit of positive focal length. The central lens unit has a positive biconvex lens surrounded by two meniscus lenses having their concave surface directed to the biconvex lens. Zooming is achieved by moving the first and fifth lens elements with respect to the central lens unit as well as by moving the overall lens system between fixed image and object planes.

Abstract: A wide-angle zoom lens system comprises, in order from the object side, a first lens group having a negative refractive power, a lens unit having a positive refractive power and a second lens group having a positive refractive power. The system performs zooming by displacing the two lens groups and one lens unit independently in the direction parallel to the optical axis while maintaining the position of the image surface constant. The system satisfies the following conditions:D.sub.IW >D.sub.IT, and D.sub.IIW >D.sub.IITwhere D.sub.I represents the aerial space between the first lens group and the lens unit, and D.sub.II designates the aerial space between the lens unit and the second lens group, with the subscripts W and T representing aerial spaces for the short and long focal length sides, respectively.

Abstract: A color corrected projection lens with a large aperture ratio and a wide angle of view for producing on a screen an enlargement of an image appearing on a CRT, the lens having sequentially from the screen end a first unit of a bi-convex element having a positive power with a strongly convex surface directed toward the screen end, a second unit of a bi-concave element having a negative power and being located at or in the vicinity of the entrance pupil position of the entire lens system, a third unit of a bi-convex element having a positive power, and a fourth unit having a negative power with a strongly concave surface directed toward the screen end.

Abstract: A compact and high-performance bright wide-angle zoom lens comprising, in order from the object side, a front group having a negative refractive power and a rear group having a positive refractive power, with a stop diaphragm being disposed between the front and rear groups. The front group, stop diaphragm and rear groups are capable of independent mechanical movement in response to a change in the focal length of the overall system. The rear group having a positive refractive power is composed, in order from the object side, of a positive lens unit, a negative lens unit, and a positive lens unit, with a lens element having a refractive index gradient profile along the optical axis being disposed in the positive lens unit on the image side of the rear group.

Abstract: A wide angle lens system of at least two, and preferably four, similar powered symmetrical component lenses is disclosed; these lenses are from object to image, at least two paired concavo-convex lenses, and preferably two lenses of a concavo-convex or convexo-convex type. The first and last lenses are displaced and rotated usually by rotation about the object (taken as a defining aperture of the optical system, such as a portion of the cornea) or its conjugate, in a first direction to use lens portions between the lens center and one edge; the intermediate lens (preferably the second and third lenses) are displaced and rotated (again usually by rotation about the image conjugate formed by the first lens) in an opposite direction to use the lens portions between the other lens edge and center.

Abstract: A telephoto zoom lens system comprises a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power. In a zooming operation, the first lens group moves arithmetically, the second lens group moves from the objective side toward the image side in the first half of the movement and then from the image side toward the objective side in the latter half of movement, and the third lens group moves so as to maintain the image side focal point thereof in a fixed position in conjunction with the first and second lens groups.

Abstract: A compact wide-angle zoom lens comprising, in order from the object side, a variator that consists of a first lens component having a negative focal length and a second lens component having a positive focal length, and a single-element fixed third lens component (relay lens system) that is positioned subsequent to the variator for increasing its focal length. The first lens component has a negative-positive lens unit arrangement. The second lens component has a positive-negative-positive lens unit arrangement. The first and second lens component are mechanically moved so as to provide a variable focal length and maintain a constant focal position. The following conditions are satisfied: ##EQU1## where f.sub.1 : the focal length of the first lens component;f.sub.2 : the focal length of the second lens component;f.sub.L : the focal length of the overall system for the narrow-angle position; andm.sub.3 : the lateral magnification of the third lens component.

Abstract: A zoom lens is known which has a first lens group having a negative refracting power and a second lens group having a positive refracting power arranged from an object side, a spacing between both the lens groups being varied to thereby vary magnification (variable power). In order to make such zoom lens compact, the refracting power of the negative lens group is intensified and the negative refracting power is arranged in a portion at the rear of the positive lens group. The portion in the positive lens group is composed of a set of positive and negative lenses, and at least one surface of the lenses is made to be an aspherical surface to correct aberrations.

Abstract: A casing has a transparent window plate sealed therein. A reflector plate is mounted on a diaphram which forms a sealed chamber with the rearwall of the casing. The casing is mounted on a conventional mirror adjustment mechanism. A plurality of conical compression springs urge the reflector plate against the inside surface of the window plate in the day position of the reflector plate. To move the reflector plate from a day position to a night position, a pump draws an optically dense light attenuating fluid from a reservoir and pumps it into an annular chamber and between the window plate and reflector plate, to move the reflector plate rearwards so that the fluid forms a masking layer between the reflector plate and window plate. The masking layer extinguishes reflections from the reflector plate in the night position. A solenoid valve prevents return of the fluid to the reservoir in the night position.

Abstract: A compact zoom finder suitable for compact cameras, video cameras and the like whose zoom ratio is about 2. While the zoom lens is composed of three units having positive, negative and positive refracting powers in order from an object side, the third unit is preferably composed of an ante-component having a negative refracting power and a post-component having a positive refracting power. In this case, an arrangement is made so that one surface in the ante-component of the third unit comprises a half mirror, and one surface in the post-component is provided with a frame to thereby provide for an albada finder.

Abstract: A lens system for use with an optical disk consisting of a positive lens (+) and a negative lens (-) cemented to the positive lens satisfying the conditions of.nu..sub.+ -.nu..sub.- >20,.DELTA.N.sub.+ /.DELTA.N.sub.- <0.1 and.DELTA.N.sub.- >0where .nu. is the Abbe number and .DELTA.N is the temperature coefficient of the refractive index, whereby the temperature and wavelength dependence of the focal length is minimized.

Abstract: A gradient index single lens has a first surface convex toward the object side, the first surface lying on the object side when the lens is used at a reduction magnification, a second surface concave toward the image side, the second surface lying on the image side when the lens is used at a reduction magnification, and an index distribution formed in the interior of the lens, the index distribution having a sphere symmetrical distribution about a certain point on the optic axis.