Abstract: A large aperture ratio zoom lens system is provided for use in a video camera. The lens system includes a first lens unit of a positive refractive power, a second lens of a negative refractive power, a third lens unit of a negative refractive power, a fourth lens unit of a positive refractive power, an aperture diaphragm, and a fifth lens unit of a positive refractive power. A second lens component in the fifth lens unit has a strong negative refractive power and has a capability to correct field curvature as well as spherical aberrations.

Abstract: The disclosed zoom lens has at least four lens groups with proper refractive powers operating such that while the third lens group counting from front is held stationary, the first and second lens groups and at least one of the fourth lens group and those that follow are moved axially in differential relation to effect zooming. A given range of variation with zooming of the image magnification of the second lens group and a given differential relation for the zooming movement of the first and second lens groups achieve good stability of aberration correction over an extended zooming range.

Abstract: A wide-angle eyepiece designed to cover a field of view of 90.degree. with substantially perfect correction of spherical aberration, coma, astigmatism, field curvature, chromatic aberration, and spherical aberration of the exit pupil.

Abstract: A beam steering mirror is trunnion mounted about a primary axis relative to ring structure and the ring structure is trunnion mounted on a secondary axis 90.degree. from the axis of the beam steering mirror and in the same plane and the ring structure is trunnion mounted about its secondary axis relative to a stationary support structure, and the ring structure and the beam steering mirror each have electric torque motor actuators for adjusting the beam steering mirror and the ring structure relative to the stationary support structure.

Abstract: A rear view mirror assembly comprising a ball and socket support member that attaches to the windshield and pivotally holds a mirror housing on a selectable over center mechanism with a multiple segmented prismoidal mirror within the housing having the central mirror segment fixed to the housing and the other mirror segments hinged vertically to the central mirror with a threadable means to adjust each hinged mirror segment relative to the housing. Such a rear view mirror assembly provides a selectable day/night setting and adjustable panoramic view.

Abstract: The disclosed zoom lens includes, from front to rear, a magnification-power variable lens assembly which serves for zooming and an image forming lens assembly which is stationary during zooming. The image forming assembly has a lens component B of negative refractive power which is preceded by at least one lens component A movable for focusing and which is followed by at least one lens component C movable for focusing. This structure makes achievement of a compact form and good stability in aberration correction possible throughout the entire focusing range.

Abstract: A zoom lens including, from front to rear, a first lens unit of negative power and a second lens unit of positive power with the separation therebetween being varied to effect zooming. The first lens unit is moved to effect focusing, wherein with the first lens unit focusing a finite object distance on the wide angle side, the second lens unit moves rearward to obtain focal lengths beyond the zooming range.

Abstract: Disclosed is a color separating a color separating lens composed of 3 lens units which is small in number of lenses, can be manufactured at less cost and can provide a good focusing performance over the entire visible area.

Abstract: In the disclosed photographic objective, a focusing lens group is arranged on the image side of a stop. To focus, all or part of the lens group, or the stop and all or part of the lens group, are moved to maintain an exit pupil at a substantially constant position.

Abstract: A zoom lens system comprising a first lens group having positive refractive power and having a focusing function, a second lens group having negative refractive power and having a vari-focal function, a third lens group having positive refractive power and having a vari-focal function, and a fourth lens group having positive refractive power and having a vari-focal function, wherein the second lens group comprises a negative lens having a surface with strong curvature on the image side, a cemented doublet consisting of a negative lens and a positive lens, a negative lens having a surface with strong curvature on the object side, and a positive meniscus lens having a surface with strong curvature on the object side, the zoom lens system having a large vari-focal ratio and a large aperture ratio and arranged compactly.

Abstract: A wide angle lens having a long back focus substantially equal to the rear focal length of the total lens system comprising six lens components with a stop between the third and fourth components from the object side satisfies the conditions:0.5<.phi..sub.2 /.phi..sub.6 <1.40.8f<f.sub.3 <1.5f0<f/f.sub.R <0.50.8f<r.sub.2 <1.5wherein f is the image-side focal length of the total system, .phi..sub.2 and .phi..sub.6 are refractive powers of the second and the sixth components, f.sub.3 is the focal length of the third component, f.sub.R is the composite focal length of the fourth to the sixth components and r.sub.2 is the radius of curvature of the image-side lens surface of the first component.

Abstract: A projection lens having a large aperture ratio has 3 units for projecting an enlargemen of an image appearing on a CRT onto a screen. The first unit from the screen has a negative power so that the entrance pupil is moved toward the screen to thereby improve off-axis vignetting factor. The second unit consists of two positive power lens elements so that the positive power of the entire system is shared by the second unit and the temperature characteristic is improved by using a positive power glass lens element as one of the two positive power lens elements. The third unit has a negative power to correct curvature of field.

Abstract: A photographic lens with a large aperture ratio comprises a plurality of lens elements brighter than F 1.5 and having a total covering power of at least 40.degree., with at least one of the lens elements being capable of passing an entire luminous flux focusing on a center of an image plane through at least 80 percent of a lens aperture thereof, and given a monotonous refractive index variation in the direction of an optical axis of the lens.

Abstract: A graded refractive index single lens system comprising at least one surface formed spherically with the radius of curvature being large wherein N.A. is large and various aberrations including off-axial aberrations are well-corrected.

Abstract: A variable focal length lens system wherein the system comprises a first lens unit of a positive refractive power, a second lens unit of a negative refractive power with a first variable air space formed between the first and second lens units, a third lens unit of a positive refractive power, and a fourth lens unit of a negative refractive power with a second variable air space formed between the third lens unit and fourth lens unit. The back focal length of the whole lens system for the shortest focal length is less than half of the diagonal length of the image plane. The first lens unit is shiftable from the image side to the object side while increasing the first variable air space in the zooming operation from the shortest focal length to the longest focal length. The fourth lens unit is shiftable from the image side to the object side while decreasing the second variable air space in the zooming operation from the shortest focal length to the longest focal length.

Abstract: A large-aperture zoom lens system comprising a first focusing lens unit having a positive focal length, a second variator lens unit having a negative focal length, a third compensator lens unit having a negative focal length and a fourth relay lens unit, said fourth lens unit consisting of a front subunit comprising at least one negative lens component and a rear subunit comprising at least two positive lens components. Said lens system comprises a small number of lens elements, and has a short total length, a long back focal distance and favorably corrected aberrations.

Abstract: A lens system is provided which is suitable for back-projecting an enlarged image of a TV cathode ray tube (CRT). To achieve a compact cabinet design 1 for such a projection television set, a short projection throw and a wide projection angle are required, together with a wide aperture (F/1) for a bright projected picture and with a definition which may need to be good enough to resolve 1249 line television pictures. The lens system comprises a concave CRT face plate FP and three lens elements L1, L2, L3. L2 and L3 are each of positive power and L1, most remote from the CRT, is a weak lens. At least one of the element surfaces is aspheric. The powers of the elements are chosen so that-0.20K<K.sub.1 <+0.15K+0.62K<K.sub.2 <+0.80K and+0.55K<K.sub.3 <+0.67Kwhere K.sub.1 is the power of the first weak element remote from the object surface, K.sub.2 is the power of the second element, K.sub.

Abstract: A zoom lens for a color video camera in which zoom ratio is 6 and F number is approximately 1.4. The zoom lens comprises a positive first group for focusing, a negative second unit for zooming, a negative third unit which is a compensator, a positive fourth unit for forming an incident divergent bundle of rays into a parallel or converging bundle of rays, and a fifth unit in the form of a relay lens composed of a front component and a rear component. Parameters, especially such as a refracting power of the first unit and second unit, are suitably selected whereby a zoom lens which is compact and which aberrations are well compensated is obtained.

Abstract: A lens system is provided which is suitable for back-projecting an enlarged image of a TV cathode ray tube (CRT). To achieve a compact cabinet design 1 for such a projection television set, a short projection throw and a wide projection angle are required, together with a wide aperture (F/1) for a bright projected picture and with a definition which may need to be good enough to resolve 1249 line television pictures. The lens system comprises a CRT face plate FP which is either flat or has a relatively shallow curavature on one or both sides and four lens elements L1, L2, L3 and L4. L1 is a weak lens, L2 and L3 are each of positive power and L4 is a negative element close to the CRT. At least two of the element surfaces are aspheric. The powers of the elements are chosen so that-0.20K<K.sub.1 <+0.10K+0.60K<K.sub.2 <+0.85K+0.35K<K.sub.3 <+0.55Kand-1.20K<K.sub.4 <-0.90Kwhere K.sub.1 is the power of the first low power element remote from the object surface, K.sub.

Abstract: In order to reduce the cost of a projecting lens system while providing excellent optical parameters for projection lenses of a series having different focal lengths but essentially the same high relative opening, all the lenses of the series utilize a common first component consisting of a positive lens, a positive meniscus and a negative lens. Only the second component is replaceable and comprises one lens or two closely spaced lenses. The second component for the longest focal length is preferably composed of low refractivity flint glass while the second component at the lowest end of the focal length range is composed of high refractivity crown glass.