Abstract: An imaging lens system includes, in the named order from the side of an object toward an image surface, a light amount diaphragm, a first lens having a positive power with a main power on the side closer to the image surface, a meniscus-shaped second lens having a negative power with a strong concave surface turned toward the image surface. Thus, it is possible to provide the imaging lens system in which a sufficiently high resolution can be obtained, while meeting the demand for a reduction in entire length of an optical system to provide the compactness.

Abstract: A zoom strobe device is provided with a light emitting unit, which includes a light source and a reflector and a light collecting lens that collects the light emitted by the light emitting unit. The light emitting unit and the light collecting lens are movable relative to each other in a direction of an optical axis of the light collecting lens. The light collecting lens is configured such that a light emitting unit side surface has a positive power, and a surface opposite to the light emitting unit side surface (i.e., the object side surface) has a negative power. The light collecting lens has a positive power as a whole.

Abstract: A telescopic lens system includes a positive first lens group, and a positive second lens group. The first lens group includes cemented lens elements having a positive lens element and a negative lens element. The second lens group includes cemented lens elements having a positive lens element and a negative lens element.

Abstract: A soft-focus lens system includes a master lens group and a soft-focus lens group. The soft-focus lens group includes a positive sub lens group and a negative sub lens group. The positive sub lens group and the negative sub lens group are moved to set the normal photographing mode or the soft-focus photographing mode. Each of the sub lens groups is arranged to move with respect to the master lens group and the other of the sub lens groups so that the focal point and the focal length are not substantially varied before and after the switching of the soft-focus photographing mode to the normal photographing mode or vice versa.

Abstract: An eyepiece lens is constructed with, in order from an entrance side for light to an exit side for light, first, second, third, fourth and fifth lens units of negative, positive, positive, positive and positive refractive powers, respectively. Each of the first, second, third, fourth and fifth lens units of the eyepiece lens is composed only of one lens or a cemented lens, and an intermediate image by an objective lens is formed between the second lens unit and the third lens unit. An objective lens is constructed with, in order from an object side to an image side, first and second lens units of positive and negative refractive powers, respectively. The first and second lens units of the objective lens are composed of one positive lens and of one positive lens and one negative lens, respectively, and the various conditions are appropriately set. An optical apparatus includes the eyepiece lens, the objective lens and an erecting prism.

Abstract: An objective lens for recording and/or reproducing an optical information recording medium, comprises a first lens having a positive refractive power; and a second lens having a positive refractive power; wherein the first lens and the second lens are aligned in this order from a light source side of the objective lens; first lens and the second lens are respectfully made of material having a specific gravity of 2.

Abstract: An optical system includes, in order from an object side to an image side, a first lens unit of positive optical power, and a second lens unit of negative refractive power, wherein focusing from an infinitely distant object to a closest object is effected by moving the second lens unit toward the image side along an optical axis, and the second lens unit consists of one negative lens.

Abstract: An optical system includes, in order from an object side to an image side, a first lens unit of positive optical power, and a second lens unit of negative refractive power, wherein focusing from an infinitely distant object to a closest object is effected by moving the second lens unit toward the image side along an optical axis, and the second lens unit consists of one negative lens. Further, it is desirable that the following conditions are satisfied: d2 L1(&lgr;)/d &lgr;2>0 d2 T1(&lgr;)/d &lgr;2<0 &ngr;2>30 where L1(&lgr;) is an aberration coefficient of longitudinal chromatic aberration of the first lens unit, T1(&lgr;) is an aberration coefficient of lateral chromatic aberration of the first lens unit, &lgr; is a wavelength of light, and &ngr;2 is an Abbe number of material of the negative lens of the second lens unit.

Abstract: A photographic optical system comprising a front lens unit which comprises at least a negative lens element and has negative refractive power as a whole, a rear lens unit which comprises at least two positive lens elements and at least a negative lens element and has positive refractive power as a whole as well as a reflecting member to fold an optical path and an aperture stop which are disposed between the front lens unit and the rear lens unit, and has an adequately defined focal length of the front lens nit and an adequately defined distance along an optical axis between the front lens unit to the aperture stop. This photographic optical system is composed of a small number of lens elements, has a large field angle and exhibits favorable optical performance.

Abstract: An objective lens includes a first lens unit constructed with a plurality of single lenses, having a negative power as a whole, and a second lens unit constructed with a plurality of single lenses, arranged on the object side of the first lens unit.

Abstract: An illumination system which ensures a numerical aperture larger than the orientation characteristics of a light sources and achieves uniform yet bright illumination is provided. The illumination system includes a light source, a collector lens constructed and arranged to converge light emitted from the light source to substantially parallel light beams and a relay lens constructed and arranged to transmit the substantially parallel light beams to an objective. The collector lens includes a first positive lens group, a second negative lens group, and at least one aspheric optical element. The working distance WD of the collector lens satisfies 0.5<WD/f<1.5 . . . (1) where WD is the distance from the center of the light source to the apex of a surface in the collector lens, the surface is located nearest to the light source side, and f is the focal length of the collector lens.

Abstract: The zoom lens system includes a positive first lens group and a negative second lens group that are arranged from an object side. The lens groups move along an optical axis to change the distance therebetween for zooming. The first lens group includes a negative first lens unit and a positive second lens unit that are arranged from the object side and each of the first and second units of the first lens group includes at least one negative lens. The zoom lens system of the present invention satisfies the following conditions (1), (2), (3) and (4); −3.1<ft/f1a<−2.5  (1) 5.8<ft/f1b<7.0  (2) 1.85<n1an  (3) 1.85<n1bn  (4) where ft is the longest focal length of the entire system, f1a is focal length of the first lens unit; f1b is focal length of the second lens unit; n1an is refractive index of the negative lens in the first lens unit; and n1bn is refractive index of the negative lens in the second lens unit.

Abstract: A zoom lens system including a positive first lens group and a negative second lens group, in this order from the object, wherein zooming is performed by varying the distance between the first lens group and the second lens group. The positive first lens group includes a negative first sub-lens-group, a positive second sub-lens-group, and a positive third sub-lens-group, in this order from the object, wherein the zoom lens system satisfies the following condition: 0.7<fT/f1-2<1.5  (1) wherein fT designates the focal length of the entire zoom lens system at the long focal length extremity; and f1-2 designates the focal length of the positive second sub-lens-group in the first lens group.

Abstract: For securing necessary brightness and back focus and favorably correcting off-axis aberrations while in a simple lens configuration, a collimator lens comprises, successively from the parallel luminous flux side, a first lens L1 made of a negative meniscus lens having a convex surface directed onto the light source side, and a second lens L2 made of a biconvex lens having a surface with a greater curvature directed onto the parallel luminous flux side. The surface of the second lens L2 on the parallel luminous flux side is formed as an aspheric surface. The collimator lens satisfies the following conditional expression (1): −0.87<R1/ƒ<−0.38  (1) where R1 is the paraxial radius of curvature of the surface of the first lens L1 on the parallel luminous flux side; and f is the focal length of the whole lens system.

Abstract: A telescopic objective lens system comprises a positive first lens group and a second lens group, in this order from the object. The second lens group comprises a first sub-lens group and a second sub-lens group, wherein the first sub-lens group is combined with the first lens group to be used for correcting axial chromatic aberration, the second sub-lens group is combined with the first lens group to be used for correcting field curvature; and wherein the combination of the first lens group and the first sub-lens group, and the combination of the first lens group and the second sub-lens group can be alternatively selected.

Abstract: A viewfinder optical system has a relay lens system. The relay lens system focuses a primary image to form a secondary image. The relay lens is provided at an optical conjugate point with respect to a pupil. A surface of the relay lens system has an optical power of diffraction. The surface is positioned between the primary image and the optical conjugate point. The surface also has optical power of refraction.

Abstract: A compact and lightweight zoom lens includes a first lens unit having a positive refractive power and a second lens unit having a negative refractive power, and performs zooming by changing the distance between the first and second lens units. The zoom lens satisfies required conditions related to the glass material, lens shape and optical power of the first and second lens units, and achieves a high zooming ratio ranging from 2.6 to 3 and high optical performance.

Abstract: In a compact wide-angle zoom lens having a two-group configuration composed of positive and negative lens groups, each lens is set to have a predetermined form and satisfy a predetermined range of conditional expression, thereby attaining a high brightness at its wide-angle end, a large angle of view, and a small lens thickness at its telephoto end. The first lens group comprises a biconcave negative first lens L.sub.1 ; a cemented lens composed of a negative second lens L.sub.2 and a biconvex positive third lens L.sub.3 ; and a biconvex positive fourth lens L.sub.4. The second lens group comprises a fifth lens L.sub.5 having an aspheric surface; a sixth lens L.sub.6 having a positive meniscus form with a convex surface directed onto the image side; and a seventh lens L.sub.7 having a negative meniscus form with a convex surface directed onto the image side. The zoom lens further satisfies the following conditional expressions:0<(r.sub.3 +r.sub.4)/(r.sub.3 -r.sub.4)<3.5, 0.5<(r.sub.11 +r.sub.12)/(r.

Abstract: A soft focus lens which is designed as a retrofocus type lens, comprises a front lens group having a negative power, a rear lens group having positive power, and a diaphragm located within the rear lens group. The front and rear lens groups are arranged in this order from an object side. In particular, the soft focus lens satisfies the following conditions;SAU/f<-0.10 (1)f/fF<-0.5 (2)whereSAU is spherical aberration at full open aperture, f is focal length of the whole lens system, and fF is focal length of the front lens group.

Abstract: A lens system is disclosed that can be used in either a normal sharp-focus configuration or in any of several soft-focus configurations for obtaining, for example, sharply focused or soft-focus photographic images of an object. The lens system has simple construction and axially comprises, in the normal sharp-focus configuration and from the object side, a first lens group having positive refractive power, an aperture stop, and a rear lens group having negative refractive power. To obtain a sharp-focus image, light passes through both lens groups and the aperture stop. For obtaining a soft-focus image, the second lens group is retracted (i.e., displaced from the optical axis such that light from the object does not pass through the second lens group), and light passes only through the first lens group and the aperture stop.

Abstract: A telephoto lens includes, in the following order from the object side, a positive cemented lens component composed of a biconvex lens and a biconcave lens and having a meniscus shape as a whole with the convex side facing the object side, and a negative meniscus lens component with the convex side facing the image side.

Abstract: An image forming lens system including a positive front lens group, a diaphragm, and a rear lens group, in this order from an object to be imaged. The front lens group is made of optical glass. The rear lens group is made of a single meniscus plastic lens having opposed aspherical lens surfaces with a concave surface adjacent to the diaphragm. The lens system satisfies the following relationships:f.sub.0 .multidot..vertline.1/f.sub.R-1 +1/f.sub.R-2 .vertline.<0.3-4<f.sub.0 /r.sub.R-1 <-0.7.DELTA.X.sub.R-1 /f.sub.0 <0.DELTA.X.sub.R-2 /f.sub.0 <00.1<d.sub.R /f.sub.0.In the above, f.sub.R-1 (=r.sub.R-1 /n-1) represents the focal length of the first surface of the plastic lens, f.sub.R-2 (=r.sub.R-2 /1-n) represents the focal length of the second surface of the plastic lens, f.sub.0 represents the focal length of the whole lens system, n represents the refractive index of the plastic lens at a reference wavelength, r.sub.

Abstract: The invention is directed to a microscope having an objective corrected to infinity and a pivotable binocular viewing unit. A tube lens is arranged downstream of the objective. The microscope includes at least one two-lens tube lens having a focal intercept greater than 200 mm as well as a tiltable mirror element and a further deflecting element mounted between the tube lens and the binocular viewing unit.

Abstract: A wide-angle photographic lens system comprising a front lens unit having a positive refractive power, an aperture stop and a rear lens unit having a positive refractive power or a negative refractive power; the front lens unit comprising at least one positive lens component and at least one negative lens component, whereas said rear lens unit consisting of a positive lens component having a convex surface on the image side. This photographic lens system has a short total length (a length as measured from a first surface to an image side surface of the lens system and a small value of .SIGMA.d (a distance as measured from the first surface to a final surface thereof), and is suited for use with collapsible mount type cameras.

Abstract: Binoculars designed to provide a large aided static field of view are provided. The binoculars are characterized by S/D ratios of above 2.8, where S is the binoculars' aided static field of view calculated by multiplying the binoculars' magnifying power by the binoculars' semi field of view in object space and D is given by tan.sup.-1 [(R.sub.ex +1.5)/13], where R.sub.ex is the radius of the binoculars' exit pupil and where R.sub.ex and the constants 1.5 and 13 are measured in millimeters. As a result of the increased S/D ratio, the binoculars of the invention minimize the sensation of tunnel vision which normally occurs when binoculars are used and reduce the user's apprehension of missing activities in his or her peripheral vision. In certain embodiments, a movable field lens unit is employed to provide variable power and a negative corrector lens unit is employed for aberration correction and to minimize the size of the binoculars. The binoculars are suitable for mass production and general consumer use.

Abstract: An optical system for recording and reading information on an optical information medium such as a video disk, a mini disk, a magneto-optical disk, and a phase change disk. The optical system includes: a light source for irradiating the optical information medium with a light beam through a coupling lens and a objective lens; the coupling lens which is a spherical single lens; and the objective lens which is a double-sided aspherical lens and provided movable along an optical axis of the light source; in which the light source is located between the coupling lens and a focal point, at a side of the light source, of the coupling lens. The optical system defines the number of a numerical aperture on the side of the optical information medium, and a lateral magnification ratio of the optical system.

Abstract: An optical lens for an optical disk drive suppresses a chromatic aberration to a sufficiently small level and attain a numerical aperture of as large as 0.55. It comprises a biconvex positive lens and a meniscus negative lens arranged in this order as viewed toward an optical disk to form a two-piece cemented lens system. The cementing surface is spherical and other surfaces are aspherical. The lenses meet the conditions of:(1) .nu..sub.1 >70(2) n.sub.1 >1.55(3) .nu..sub.1 -.nu..sub.2 >45(4) 1.1<{-r.sub.2 /(f.multidot.NA)}<1.5where .nu..sub.1 is an Abbe's number of positive lens, .nu..sub.2 is an Abbe's number of the negative lens, n.sub.1 is a refractive index on a d line of the positive lens, r.sub.2 is a radius of curvature of the cementing surface, f is a combined focal distance of an entire system and NA is a numerical aperture of the entire system.

Abstract: A light-weight clinical viewer includes a two-element objective lens and a single-element eyepiece lens. Use of multiple lenses allows for a more compact package. The doublet objective serves to reduce vignetting while providing a wide field of view and reduced chromatic aberration. Image quality is further enhanced, while keeping the weight of the viewer down, through the use in the objective of light-weight high index glass. Moreover, the invention permits the use of a single mounting barrel assembly for different eyepieces to reduce manufacturing costs.

Abstract: A telemicroscopic lens configuration for high quality optical imaging applications which provides high magnification of a work area with a wide field of view. The telemicroscopic lens configuration is a Galilean-type configuration having a positive-power objective lens and a negative-power eyepiece lens separated by an air space. The focal length of the objective lens and the air space distance are optimized to provide the magnification and overall effective focal length of the instrument. The focal length of the eyepiece lens is chosen so that the object being magnified appears in front of the viewer. Different lens materials are selected to minimize polychromatic aberrations. The shape of the objective lens, including radius of curvature and thickness of each lens element, is optimized to minimize monochromatic aberrations, which principally include spherical aberration and coma.

Abstract: A wide-angle zoom lens has a first lens group having a positive refracting power and a second lens group having a negative refracting power, which are moved relative to each other along the optical axis so as to attain zooming. The first lens group is constituted in turn from the object side by a front group having a negative refracting power and a rear group having a positive refracting power. The front group has at least one negative lens. The rear group has at least two positive lenses. The zoom lens is constituted to satisfy the following conditions:0.75<.vertline.f.sub.F /f.sub.W .vertline.<4, f.sub.F <00.1<K/f.sub.W <0.40.1<L/f.sub.W <0.7wherein f.sub.F is the focal length of the front group in the first lens group, f.sub.

Abstract: A compact scanning optical system for effecting a superior tilt surface correction and for reducing a field curvature. The system is provided with a focusing optical system which is composed of a first single lens and a second single lens, wherein the first single lens, with a positive refracting power in a plane of scan, has a toric surface from an image plane and the second single lens, with a negative refracting power in the scan plane, has an aspherical lens.

Abstract: An image reading lens that is constructed of, in succession from the object side, a stop, a meniscus-shaped positive first lens having its convex surface at the image plane side, and a negative second lens having its concave surface at the image plane side. Both the lens surfaces of the first lens and at least one lens surface of the second lens are constructed of an aspherical surface. The shape of the object side aspherical surface of the first lens is formed so as to be inside a reference spherical surface.

Abstract: A zoom lens having two units of lens components including from the object side a positive optical unit and a negative optical unit. The positive optical unit includes two lens subunits, a weak power subunit, and a positive power subunit, while the negative optical unit consists of a negative lens component and provides most of the magnification change during zooming.

Abstract: An autofocusable soft focus lens system includes a movable front lens group having a positive power, and a stationary rear lens group having a negative power.

Abstract: A temperature-compensated optical system for a scanning device. The optical system includes a first optical element having a positive radius of curvature in a plane and a second optical element having a negative radius of curvature in the plane. Both optical elements focus light energy to nearly the same point within a housing of the scanning device. The focal point is on the side of the second optical element that is opposite to the first optical element. In one embodiment, the optical system can be two separate optical elements and, in another embodiment, the optical system can be an integral piece of material, such as plastic, with the first and second optical elements being surfaces on opposite sides of the integral piece.

Abstract: An optical beam scanner capable of correcting irregularities in pitch of beam scanning as caused by inclination or angular deviations of reflective deflection surfaces of a deflector, the scanner including a first image-forming optical system arranged to form an image of a light beam from a light source linearly on or in the vicinity of a reflective deflection surface of a deflector, and a second image-forming optical system arranged to form an image of the deflected light beam from the deflector on a scanning surface. The second image-forming optical system is constituted, successively from the side of the deflector, by a first singular lens element provided with at least one toric surface and having positive refractive power in a plane of transverse main scan direction, and a second singular lens element provided with either a spherical or cylindrical surface and having negative refractive power in the plane of the main scan direction.

Abstract: A condensing optical system for condensing light from a record medium onto a photodetector in such as an optical information recording/reproducing system, comprises a first lens group and a second lens group, and these first and second lens groups cooperate to correct aberrations, especially a chromatic aberration, in the system with respect to plural wavelengths of lights esp. by making Abbe's numbers of those first and second lens groups different from each other.

Abstract: An infrared objective device with optical achromatization and athermalization comprises a front convergent assembly having at least one divergent lens acting as a port and one convergent lens, and a rear divergent assembly comprising at least one divergent lens. These three lenses are chosen so as to be made of three different materials of the type that can be used in the 8 to 12 .mu.m spectral band. They may notably be made, respectively, of germanium, chalcogenide and zinc sulphide.

Abstract: A photolithographic projection optical system comprising: a source of exposure energy for generating a beam of energy; an optical element located in the path of the beam for receiving the beam of energy and passing the beam therethrough; a refractive lens assembly located in the path of the portion of the beam for receiving and transmitting the beam of energy, the refractive lens assembly comprising at least one meniscus lens, a plano-convex lens, and an air gap disposed between the meniscus lens and the plano-convex lens; a reticle element located in the path of the portion of the beam, the reticle element having a uniform thickness and being positioned for permitting the beam to pass through the thickness and through the lens assembly to the optical element. Alternatively, the air gap of the refractive lens assembly can be replaced with a glass layer having an index of refraction that is lower than both the meniscus lens and the plano-convex lens.

Abstract: The present invention relates to an improved collimator assembly that includes two separate optical paths. Each optical path passes through a corrector lens arrangement substantially centered and aligned with one of two eyepiece lens assemblies. Each corrector lens arrangement is constructed so as to selectively refract light passing through it, in such a manner so as to counteract and reduce the axial chromatic aberrations that occur in the eyepiece lens assemblies.

Abstract: A stereomicroscope includes an objective lens used in common and a pair of observing optical systems on the left and right sides, arranged behind the objective lens so that optical axes of the observing optical systems are symmetrically arranged at a predetermined angle with respect to an optical axis of the objective lens. In the stereomicroscope, the objective lens may be arranged so that a focal length of the objective lens has a positive value and an object is located closer to the objective lens than an object focal point of the object lens, and thereby an image which is high in resolution and favorable in flatness is brought about.

Abstract: A small type zoom lens composed of 3 to 5 lenses, which is suitable for a compact camera. The lens has a telephoto type optical arrangement including a positive first lens unit and a negative second lens unit, both of the lens units being moved forward as a whole while narrowing a space therebetween during variation of power from a short focal end to a long focal end. The first lens unit has an arrangement of refracting powers substantially symmetrical with respect to a diaphragm to correct aberrations produced by the second lens unit composed of a negative single lens.