Abstract: An ultra compact zoom lens system includes: a first lens unit having a positive refracting power and including a positive lens, a negative lens and a cemented lens comprised of a negative lens and a positive lens; a second lens unit having a negative refracting power and including a positive lens and a negative lens; and a third lens unit having a positive refractive power and including a positive lens. The second lens unit has a paraxial lateral magification which is always larger than unity and the third lens unit is fixed in position. And, the focal distance of the entire system is varied by varying a spacing between the first and second lens units and a spacing between the second and third lens units relative to each other.

Abstract: A wide-angle reading lens system is disclosed which comprises, in order from the object side, a first lens element which is a negative meniscus lens having its convex surface directed toward the object side, a second lens element which is a positive lens having a strong convex surface directed toward the object side, a third lens element which is a negative lens, and a fourth lens element which is a positive lens having an strong convex surface directed toward the image side, said lens system satisfying the following conditions:-2/0f.ltoreq.f.sub.1 .ltoreq.-0.75f (1) ##EQU1##d.sub.1-7 .ltoreq.0.85f (3)where f denotes the overall focal length of the system; f.sub.1 is the focal length of the first lens element; n.sub.i is the refractive index of an ith lens at the d-line; .nu..sub.i is the abbe number of the ith lens; and d.sub.1-7 signifies the distance from the surface of the first lens element on the object side to the surface of the fourth lens element on the image side.

Abstract: A rear view mirror mounted either interiorly or exteriorly of a vehicle which incorporates a unique structure providing an illuminated, feather-touch, bar switch for actuating a solenoid to change the mirror from day-to-night and night-to-day positions by utilizing a single finger, feather-touch operation. The mirror also includes a map light or lights located along the lower edge thereof with the map light or lights being actuated by a feather touch switch or switches and icluding a downwardly facing fresnel lens to direct a light beam for easy map reading and a shield or baffle to prevent light rays from entering the eyes of the vehicle operator. A mechanical memory switch and push/pull solenoid may be utilized as an alternative to magnetically latched solenoid and circuitry therewith.

Abstract: A variable focal length objective of which at least one of a pulrality of lens units is moved to vary the image magnification, wherein at least one of the plurality of lens units has at least one refractive index distribution type lens provided with a condition of N.sub.1 >0 as, taking the distance from the optical axis to a radial direction as h, the refractive index distribution is expressed by N(h)=N.sub.0 +N.sub.1 h.sup.2 +N.sub.2 h.sup.4 +N.sub.3 h.sup.6 +. . . (N.sub.0, N.sub.1, N.sub.2 . . . are constants), and satisfies the following conditions: ##EQU1## where fmax: the maximum focal length;fmin: the minimum focal length;Lmin: the optical total length when the total length is shortest;Y: the maximum image height;N.sub.1 *: the coefficient of h.sup.2 of the refractive index distribution type lens having a refractive index distribution of N.sub.1 >0;D*: the lens thickness of the refractive index distribution type lens having the refractive index distribution of N.sub.1 >0.

Abstract: A zoom lens whose first lens group, counting from front, has a negative refractive power and moves axially in differential relation to a following lens group to effect zooming, wherein the first lens group is constructed with a lens unit of negative power followed by another lens unit of positive power, whereby for focusing purposes, the negative lens unit is axially moved, while the positive lens unit is held stationary, to improve the stabilization of aberration correction throughout the entire focusing range.

Abstract: A wide-angle objective of compact construction and comparatively small diameter has its first lens element formed as a convex negative meniscus and its last or sixth lens element formed as a biconcave construction with the fourth lens element being a thick cemented lens.

Abstract: A macro lens system consisting from the object side of a front unit of negative focal length, a middle unit of positive focal length and a rear unit of large focal length. During focusing, all lens units are displaced. Additionally the front and middle units are displaced en masse with respect to the rear unit. Numerical conditions are given on the focal length of the front unit and of the combination of the front and middle unit and on the relative displacements during focusing.

Abstract: An inventive light-shader can prevent reduction of contrast ratio of views in a display, generation of moires and devastion of images in the views. The light-shader is made up of a light-shading film and a light-transmissive substrate plate. The film includes a plurality of opaque walls standing along its thickness and defining corresponding light-transmissive cells. The light-transmissive substrate plate has one surface attached to one surface of the film and the other surface microscopically rugged. The light-shader is applicable to automotive television sets, computer displays, indicative plates of various meters of automotive vehicles, ships and airplanes, and the like.

Abstract: A projection lens for projecting an image onto a screen includes, in succession from the screen side, a first lens component having a positive refractive power, a second lens component having a positive refractive power and whose both lens surfaces are convex surfaces, a third lens component of meniscus shape having its convex surface facing the screen side, and a fourth lens component having a negative refractive power and whose surface which is adjacent to the screen is a concave surface.

Abstract: This specification discloses a single lens having an index gradient in a direction perpendicular to the optic axis thereof, and the surface of the single lens on the light beam incidence side when the single lens is used at a reduced magnification is formed into a surface concave relative to the object side, whereby the working distance is sufficiently long and aberration are well corrected.

Abstract: A telephoto lens system which can focus down to unity magnification comprising two lens groups that are displaced during focusing. The front lens group of positive refractive power has five or six elements, namely, a positive lens, a positive meniscus lens, a negative lens, a lens element with a slightly negative refractive power and a positive lens. The rear lens group of negative refractive power has three elements, namely, a positive, a negative and a positive lens element. Additionally, there are four numerical conditions on focal lengths and radii of curvature.

Abstract: Optical viewing or projection device, comprising at least two objectives (L.sub.1 L.sub.2) whose optical axes (x.sub.1 x'.sub.1 ; x.sub.2 x'.sub.2) are parallel to a general axis of symmetry (xx') of the device, endowed with a focusing system permitting the formation of images or viewing in a fixed reference plane (P'.sub.0), by means of simultaneous translation of the objectives in parallel to the general axis of symmetry, and comprising means for reducing the parallax produced by the objectives, the means for reducing the parallax including a system of parallel-faced plates (M.sub.1 M.sub.2) which has the general axis of symmetry (xx') of the optical device as its axis of symmetry, wherein a parallel-faced plate is placed between each objective (L.sub.1, L.sub.2) and the fixed reference plane (P'.sub.

Abstract: The lens includes a transparent body having a central section and a peripheral section. The central section has a surface with a truncated elliptical curvature. The peripheral section has an inner refracting surface and an outer reflecting surface. The inner refracting surface has a diverging truncated conical shape. The outer reflecting surface has a parabolic shape.

Abstract: A four element optical magnifying system (10) is disclosed. The primary lens (12), secondary lens (14), tertiary lens (16), and quaternary lens (18) form an optical system (10) have surfaces shaped to focus upon an object such that a high resolution image is formed at infinity at 4.times. magnification substantially over the entire field of view.

Abstract: A rear conversion lens to be mounted in between an objective lens and a determined image plane to produce a composite focal length longer than the focal length of the objective lens itself comprises, in the order from the object side a first lens component, a second lens component and a third lens component. The first lens component has a positive focal length and the image-side lens surface being convex toward the image side. The second lens component has a negative focal length and the object-side lens surface being convex toward the image side. The third lens component has a negative focal length and is in the shape of a meniscus convex toward the image side.

Abstract: For small type wide angle lenses for use with a compact camera, so-called inverted retrofocus lenses are often used. In this type of lens, the lens can be formed into more compact by increasing a refracting power of a rear unit of a negative meniscus with a convex surface thereof greatly curved toward an image and a front unit on the side of an object. However, this arrangement gives rise to an aberration. This aberration can be compensated by introducing at least one aspherical surface into the front unit and rear unit. In addition, this aspherical lens can be easily produced if it is formed of plastics.

Abstract: A zoom lens comprising four lens groups the fourth group of which is composed of a front group and a rear group and the rear group is movable in a determined relation with the third lens group along the optical axis for compensating the variation of aberrations caused by zooming so that the zoom lens can always maintain good image-forming performance through the wide zooming range.

Abstract: An imaging single lens in which perfectly, a first surface is an axis-symmetrical non-spherical surface having a radius of curvature r.sub.1 in the vicinity of the optical axis, a second surface is a convex spherical surface having a radius of curvature r.sub.2, the center thickness is d, the non-spherical shape of the first surface is a shape displaced outwardly from the central portion to the marginal portion relative to a reference spherical surface of radius r.sub.1, and as p.ident.-r.sub.2 /d, p is 1 or a value approximate to 1.

Abstract: The present invention provides a viewfinder optical system of inverted Galilean type which has a great magnification relative to the diameter of the objective lens without increasing the number of parts. The viewfinder optical system consists of, from the object side to the eye side, an objective lens component having a negative refractive power and an eyepiece lens component having a positive refractive power. The eyepiece lens component has a convex surface at the eye side. The viewfinder optical system fulfills the following conditions:0.4L<d.sub.3 <0.85L-1.4<L/R.sub.4 <-0.8 R.sub.4 <00.35<.vertline.R.sub.2 /R.sub.4 .vertline.<0.65wherein:L represents the total length of the whole viewfinder optical system;d.sub.3 represents the axial thickness of the eyepiece lens component;R.sub.2 represents the radius of curvature of the eye side surface of the objective lens component; andR.sub.4 represents the radius of curvature of the eye side surface of the eyepiece lens component.

Abstract: An optical element (10) is pivoted for limited rotation about an axis (12). An actuator arm (14) is rotatable by an actuator (13) about an axis (15) and is connected to the optical element by a first link (16). A second link (21) connects the actuator arm (14) to a balance arm (18) which carries a balance mass (20) and is pivoted about an axis (19). The arrangement is such that the line (23) joining the axis (12) of the optical element to the point of connection between the first link (16) and the optical element (10) is always parallel to the line (24) joining the axis (19) of the balance arm (18) to the point of connection between the balance arm and the second link (21).