Abstract: A bright and very compact telephoto lens system which is capable of effective aberrational compensation at infinity and with minimal aberrational variations when focused at near distances using inner focusing. The lens system includes a first lens group having a positive refractive power, a second lens group having a positive refractive power and a third lens group having a negative refractive power. The first lens group is composed of a positive first lens element, a positive second lens element, a negative third lens element and a positive fourth lens element. The second lens group includes a cemented positive lens in which a positive fifth lens element is cemented to a negative sixth lens element. The third lens group is composed of a cemented negative lens in which a positive seventh lens element is cemented to a negative eighth lens element, and a positive meniscus ninth lens element having a convex surface directed toward the object side.

Abstract: A wide angle, finite conjugate lens is optimized for use in photocopying applications. Two moveable groups of lenses are movable towards and away from each other and a central aperture. An outer lens group pair is moveable with respect to a moveable inner lens group. The lens groups are moved during a zoom magnification change so that the spaces between the inner and outer lens groups are changed to adjust lens focal length while the space between the inner lens group and a central aperture stop is adjusted to compensate for astigmatism and field curvature variation.

Abstract: A lens system has a lens unit comprising a positive lens and a negative lens. The positive lens has an index distribution in the direction of the optic axis. The value of the index gradient for a light having a short wavelength in the vicinity of the vertex of at least one convex surface of the positive lens is smaller than the value of the index gradient for a light having a long wavelength.

Abstract: An optical apparatus is described for scanning an optical record carrier comprising a radiation source supplying a scanning beam, a reflector for directing the scanning beam to the record carrier and an objective lens for focussing the beam to a scanning spot on the information surface . The mounting height of the apparatus is considerably reduced by integrating the objective lens and the reflector in a single reflector-objective element.

Abstract: An objective for an endoscope comprising, in the order from the object side, a first lens unit I having negative refractive power, a second lens unit II having positive refractive power, a third lens unit III having positive refractive power, an aperture stop S arranged between the front end of the second lens unit and rear end of the third lens unit and a fourth lens group IV comprising a lens component which has a concave surface on the object side, the four unit objective for an endoscope being arranged so that the overall length is short, outer diameter of the objective is small, angle of view is wide, intensity of light in the marginal portion is high, and distortion is corrected favourably.

Abstract: The present invention is a variable magnification lens system with a constant object-image distance. The lens system comprises an aperture stop, two fixed lens units constructed symmetrically with each other and two movable lens units constructed symmetrically with each other and located between the two fixed lens units, wherein the two lens units are positioned symmetrically with each other with respect to the aperture stop at the time of equal magnification, while the two lens units are positioned asymmetrically with each other with respect to the aperture stop during other magnification ratios.

Abstract: A compact zoom lens comprising, from front to rear, a first lens unit of positive power for focusing, a second lens unit of negative power monotonously movable for zooming, a third lens unit held stationary during zooming, and a fourth lens unit of positive power to move in a locus convex toward the front to maintain the constant position of an image plane which shifts as the image magnification varies, a fixed stop for determining F-numbers being located between the second and third lens units.

Abstract: A variable focus optical element comprises plural elastic members superposed in the axial direction and a deforming member having an aperture to cause the elastic member to protrude therefrom or descend therein thereby deforming the surface of the elastic members, and the modulus of elasticity of an elastic member at the protruding side is selected larger than that of another elastic member adjacent to first-mentioned elastic member at the protruding side.

Abstract: The Fresnel lens concentrator is formed by a specially designed Fresnel lens and a solar cell located on the axis of the lens at its focal plane. The lens is designed so that its central facets project the light from the sun towards the outer periphery of the cell and facets progressively toward the periphery of the lens project light progressively toward the center of the cell to obtain a uniform distribution of light on the cell. Adjacent groups of facets of the lens project the light alternately in front and beyond the cell to maintain a constant light intensity for a certain depth of focus of the lens.

Abstract: The specification discloses an automatic rearview mirror which more accurately responds to the glare-reduction needs of the vehicle operator. The mirror includes a reflective element, a light sensor, and a control circuit for regulating the reflective state of the mirror in response to the light sensor. The light sensor includes a detector responsive to electromagnetic wavelengths and a filter for filtering the wavelengths received by the detector so that the spectral response of the light sensor approximates the spectral response of the human eye or standard C.I.E. observer. The light sensor therefore detects the same wavelength intensities as does the vehicle operator.

Abstract: A substantially unity magnification image forming system includes at least one convex mirror and at least one concave mirror supported with their centers of curvature substantially coincident and means to define a location for an oject the image of which after at least three reflections including at least one reflection at each of said mirrors is a real image at a second location and a monocentric meniscus lens between the mirrors to give overall correction for Petzval sum.

Abstract: A telephoto lens system, both compact and capable of close-in focusing, comprising, in order from the object side, a first lens unit of positive power, a second lens unit of negative power, a third lens unit of either power and a fourth lens unit of positive power. There are additionally imposed five numerical conditions on the focal lengths of the lens units, their separation and their displacement. The second and third lens units are displaced by differing amounts for focusing.

Abstract: A large aperture long focus macro lens system comprising a first lens group having positive refractive power, a stop, a second lens group having positive refractive power, and a third lens group in the order from the object side, the large aperture long focus marco lens system being arranged to be focused on an object at a short distance by advancing the lens system as a whole in the state that the first lens group, the stop and the second lens group are advanced integrally by varying the relative airspace in respect to the third lens group, the large aperture long focus macro lens system being arranged that aberrations are corrected favorably and the variation of aberrations at the time of focusing is small and that the working distance does not become short and the advancing amount of the lens system does not become large when focused on the object at a very short distance.

Abstract: A six element optical magnifying system (10) is disclosed. The primary lens (12), secondary lens (14), tertiary lens (16), quaternary lens (18), quinary lens (20), and sextiary lens (22) form an optical system (10), having surfaces shaped to focus upon an object such that a high resolution image is formed at infinity at 10.times. magnification substantially over the entire field of view.

Abstract: A high definition projection lens for projecting on a screen an enlargement of an image appearing on a high resolution CRT is disclosed. The projection lens comprises a first lens having a positive optical power and a convex surface facing the screen, a meniscus second lens having a positive optical power, a third lens having bi-concave surfaces and a negative optical power, a fourth lens having a positive optical power, a fifth lens having bi-convex surfaces and a positive optical power, and a sixth lens having a negative power and an aspheric concave surface facing the fifth lens.

Abstract: A zoom lens including a plurality of movable lens units for zooming, a diaphragm and a beam splitter for splitting off part of the light beam toward an optical device, characterized in that this beam splitter is arranged in between the frontmost and rearmost movable zoom units.

Abstract: A scanning lens system for a light beam scanning device in which a light beam emitted from a light source is shaped by a beam shaping optical element into a linear image to enter a surface of a deflection member and the beam deflected by the deflection member is restored to a circular-like image and projected onto an objective surface by the scanning lens system. The scanning lens system consisting of from the deflection member side a first, second and third single lens, the first single lens being a spherical lens with a positive refractive power, the second single lens being a toric lens with a negative refractive power in a scanning plane and with a positive refractive power in a plane perpendicular to the scanning plane, and the third single lens being a spherical lens with a positive refractive power.

Abstract: A display-monitor shield assembly (10) comprises a rigid monitor shield (12) having parallel hinges (26, 28, etc.) extending along the length thereof, and a belt (16) and buckle (14) attached thereto for looping tightly about display monitors to hold the display monitor shield assembly thereon. The belt and buckle are attached to a hinged tab (36) at a mounting end of the shield and the tab and other contact portions of the shield include friction pads (19, 20, 21, etc.) on inside surfaces thereof so that moderate pressure of the belt against these pads holds the shield assembly tightly on the display monitors but yet allows adjustment of the shield. Side panels (61,62,etc.) of the shield can be folded up so that the shield assembly can be made smaller to be placed on smaller display monitors.

Abstract: In order to make it possible to observe the image of an object as an erect (correct) image and also to construct the entire device in a compact size, the optical system for altering the direction of the visual field for use in endoscopes comprises visual field direction altering means composed of the combination of a first prism having a light-incidence surface normal to the optical axis of the incident light and a second prism having a light-emitting surface normal to the optical axis of the optical system located rearwardly of the first prism, and arranged so that the vertical angle between the light-incidence surface and the light-emitting surface of the first prism and the vertical angle between the light-incidence surface and the reflection surface of the second prism are structured, respectively, to satisfy certain specific conditions. This visual field direction altering optical system can be constructed as an adapter removably mounted to the foremost end portion of the endoscope.

Abstract: The image-transmitting optical system comprising two rod-like lens components, at least one component having a concave air-contact surface, and at least one component including an inhomogeneous lens. In this optical system, curvature of field is eliminated, the loss of illumination intensity and the amount of flare are small, and the deterioration of the image by the decentering is also small.