Abstract: A light beam focusing system provides a diffraction limited spot across a wide flat field format by using a scanning surface arranged with a system of spherical mirrors to achieve dynamic field flattening. The scanning surface is pivoted about an axis of rotation to image the beam along a noncircular image line, and the spherical mirror system provides magnification of the image in a sense and amplitude to provide a substantially uniform focused scanning spot throughout the flat object field. The system compensates for higher order spherical aberrrations, is fully achromatic and can be used with high power beams.

Abstract: The present invention provides a lens system for projecting to a screen a video image formed on a face plate of a cathode ray tube. The lens system comprises, from the screen side to the tube side: a first positive lens unit; a second positive lens unit; a third negative lens unit having a screen side surface convex to the screen side; a fourth lens unit of bi-convex lens; and a fifth negative lens unit having a screen side surface concave to the screen side, at least the fourth lens unit being made of glass material, wherein the lens system includes at least one aspheric surface and fulfills the following conditions: ##EQU1## wherein; f represents the focal length of the whole lens system; f.sub.1 represents the focal length of the first positive lens unit; f.sub.2 represents the focal length of the second positive lens unit; f.sub.3 represents the focal length of the third negative lens unit; and .nu..sub.3 represents the Abbe number of the third negative lens unit.

Abstract: Disclosed is a compound lens system consisting of a main lens system and a rear conversion lens system located at the image side of the main lens system, wherein the rear conversion lens system comprises, from the object side to the image side, a first positive single lens component made of a synthetic resin material and having an aspheric surface and a second negative compound lens component consisting of a positive lens element and a negative lens element. The first positive single lens component has a refractive index of a determined value between 1.4 and 1.6. The difference value between a refractive index of the negative lens element and a refractive index of the positive lens element of the second negative compound lens component is selected to be between 0.01 and 0.4. The aspheric surface of the first positive single lens component is formed in such a manner as to compensate for a coma aberration, excessive compensation of a spherical aberration and excessive compensation of field curvature aberration.

Abstract: A compact zoom lens system with a zooming ratio of about 2 and a large aperture ratio comprises, in order from the object side, a front lens group having a positive refracting power and a rear lens group having a negative refracting power, which is arranged to be zoomed by varying the space between the both lens groups, and in which the front lens group comprises a negative lens component and a positive lens component and the rear lens group comprises a positive lens component and a negative lens component so that this lens system comprises four components as a whole.

Abstract: An Albada type inverted Galileo finder which is suitable foruse with a compace lens shutter camera, which is small in size, and which is visible without occurrence of any ghost not only in an object but a finder frame.If lenses are disposed in order of negative, positive and positive from the side of an object and a reflecting surface of an Albada system is a surface on the side of the object of a positive lens, a finder which involves no ghost and is advantageous for correction of aberrations can be obtained. Furthermore, if the on-the-axis thickness of each lens is restricted to thereby provide a plastic lens, precision of molding can be improved.

Abstract: An aspherical single lens of compact construction and good image-forming performance which is obtained by shaping the first surface into such an aspherical configuration the curvature radius of which increases gradually toward the periphery from the center while satisfying the following conditions:0.42<q<1.3 (a)and0.5(f-1)<d<1.2f (b)wherein, q=-r.sub.1 /r.sub.2, r.sub.1 is the curvature radius in the vicinity of the optical axis of the first surface, r.sub.2 is the curvature radius of the second surface, f is the focal length and d is the thickness of the lens.

Abstract: It is a lens comprising three elements for a scanning device; the lens is particularly for providing a linear scanning. A beam enters the lens from its front focus by rotating a constant angular velocity, will become a beam in parallel with the axis of the lens and moving at a contant speed when passing through the lens; the distance H between the beam and the axis of the lens, the contained angle .theta. between the incident beam and the axis of the lens have the relation of H=KF.theta., in which F is the focal length of the lens, and K is a constant.

Abstract: A compact wide-angle zoom lens with short back focus comprises a forwardmost negative power lens unit movable for focusing and compensation during zooming, followed by a positive power variator lens unit comprising a forward positive power lens sub-unit movable for zooming and a rearward lens sub-unit also movable for zooming.

Abstract: A zoom lens system for use in microfilm projection apparatus in which the image projection is conducted in a condition of a definite object-image distance, the system comprising from the enlargement side to the reduction side, an aperture stop disposed fixedly, a first lens group of a positive refractive power located near the aperture stop at the longest focal length side, a second lens group of a negative refractive power, and a third lens group of a positive refractive power, wherein the first to third lens groups are moved along the optical axis while increasing a distance between the first and second lens groups and decreasing a distance between the second and third lens groups in an operation of zooming from the longest focal length side to the shortest focal length side.

Abstract: A compact high vari-focal ratio zoom lens system comprising a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a fourth lens group having negative refractive power, in the order from the object side, and arranged to move respective lens groups toward the object side at the time of zooming from the wide position to the teleposition, the compact high vari-focal ratio zoom lens system being arranged to adequately distribute the refractive power to respective lens groups and thereby arranged to have a high vari-focal ratio, to be small in sized and to have favorable performance.

Abstract: A zoom lens having a plurality of lens units at least one of which includes a variable refractive index element for zooming and focusing purpose. The refractive index of the variable refractive index element of the zoom lens is varied by an output from an auto-focus detection device.

Abstract: A light-shielding screen comprising a light non-transmitting, photocured resin composition layer and a plurality of hollow portions having their respective upper and lower openings and passing through said composition layer, the hollow portions each having an inner wall extending from the circumference of each upper opening to the circumference of each lower opening substantially in parallel with the axis of said hollow portion. Such light-shielding screen is produced by image-wise exposing a layer of a photocurable resin composition to actinic radiation through an image-bearing transparancy to convert the layer to a modified layer having photocured portions and a plurality of uncured portions and then removing the uncured portions by means of a developer to form hollow portions passing through the modified layer and having their respective upper and lower openings.

Abstract: An ojective lens for use in an optical pickup that is employed in a compact disk player, for example. The objective lens has a first aspherical surface on which parallel light rays impinge and a second spherical surface that faces the disk. The aspherical surface lies in a meridian plane of a cartesian coordinate system. The X-axis of this coordinate system is taken on the optical axis, the Y-axis is taken at the apex of the aspherical surface. The aspherical surface which is axially symmetrical is given byx=(y.sup.2 /r.sub.1)/{1+.sqroot.1-(k+1) (y.sup.2 /r.sub.1.sup.2)}+d y.sup.4 +e Y.sup.6 +f Y.sup.8 +g y.sup.10where r.sub.1 is the radius of curvature of a reference inscribed sphere at the apex of the aspherical surface, k is a conic constant, d, g, f, and g are expansion coefficients of the fourth, sixth, eighth, and tenth orders, respectively. The lens satisfies the following three relations:(1) 0.34<(N/2)-{N.sup.2 -1)/N.sup.2 }(r.sub.1 /F)<0.38(2) (1.1.times.N)-2.55<k<(0.5.times.N)-1.35(3) N.

Abstract: A lens arrangement for redirecting beams of light which diverge in a generally conical pattern from a fixed light source comprises a lens member configured and located relative to the light source for passing the diverging beams of light from the fixed light source therethrough substantially without changing the direction of the beams in a first plane, and for redirecting others of the diverging beams of light from the light source into substantially parallel beams of light as they pass through the lens member in substantially any one cross-sectional plane through the lens member which is substantially perpendicular with the first plane.

Abstract: A vari-focal lens system comprising a first lens group having a positive focal length, a second lens group having a negative focal length, a third lens group having a positive focal length, and a fourth lens group having a positive focal length in the order from the object side and arranged that the first and third lens groups are always kept fixed, the second lens group is arranged to be movable when varying the focal length of the lens system as a whole and to be kept fixed at the time of focusing, the fourth lens group is arranged to be movable for the purpose of compensating the displacement of the focal point which occurs when varying the focal length of the lens system as a whole and to be movable also for the purpose of focusing, and the rays coming out from the third lens group becomes approximately afocal, the vari-focal lens system being further arranged that the lens group to be moved for focusing is light in weight and, moreover, arranged to have a large aperture ratio, high vari-focal ratio and h

Abstract: An improved high-performance zoom lens system for a compact camera is disclosed. The lens employs a two-group type configuration composed of a first lens group having a positive focal length inclusive of a stop diaphragm and a second lens group having a negative focal length. To reduce the diameters of the lenses in the rear group, the back focus of the overall lens system is made greater than a predetermined value, while yet the overall lens system remains relatively short.

Abstract: A wide-angle close-focus zoom lens for a single lens reflex camera, said lens having no more than a total of three independent movable lens element units or sub-units. The lens can have as few as eight lens elements without requiring any aspheric lens element surfaces.

Abstract: An objective for endoscopes with a lateral objective lens comprises an elongated prism having a convex proximal end surface and a distal end on which are joined by cementing after alignment on an optical axis, a diaphragm, a negative lens and optionally a wedge-shaped support, to form an indissoluble unit. The lens, the diaphragm and the support if present are provided with sections protruding radially beyond a desired periphery of the objective, which sections are ground off together to the dimension of the prism circumference, so that a rod-shaped objective unit is formed.

Abstract: A sunshade for attachment to the end of a rifle scope or receiver for blocking the sun's direct rays or light from other sources from entering a shooter's eye when the shooter is aiming at a target in the general direction of the sun or source of light. The sunshade is adapted to surround the rear eyepiece of the rifle scope or be placed proximate the rear sight of a rifle and employs a shield to protect against direct light from the luminous source entering into the shooter's eyes. The shield, taking generally the shape of a semi-circle, is made from most any material, hard or flexible, and is supported in place by means of internal reinforcements which attach to a clamp or other structural mechanism adapted to reside around the scope rear eyepiece or attached to the rifle receiver. For bolt action rifles, the shield is made of flexible meterial in order that the bolt of the rifle may be drawn past the shield by the shield flexing out of the way.

Abstract: A copying zoom lens comprising, in order from the object side, a first lens unit having a negative focal length, a second lens unit having a positive focal length and a third lens unit having a negative focal length. An axial space between the first and second lens units and an axial space between the second and third lens units are varied while moving an overall lens system and keeping constant a distance between the object and an image surface, thereby performing a zoom effect. The first lens unit is composed of a single negative meniscus first lens element having a concave surface directed to the object. The second lens unit is composed, in order from the object, of positive second lens element, a negative third lens element, a negative fourth lens element and a positive fifth lens element to constitute a three-lens element subsystem. The third lens unit is composed of a single negative meniscus sixth lens having a concave surface directed to the image surface.