Abstract: In a retro-focus type objective lens for an endoscope, its front-group concave lens system is constituted by two concave lenses, and a predetermined conditional expression is satisfied, so as to secure a sufficient length of back focus, while fully favorably correcting chromatic aberration in magnification. A four group lens configuration having five lenses comprising a front-group concave lens system composed of two concave lenses L.sub.1 and L.sub.2, a rear convex lens system composed of lenses L.sub.3 and L.sub.5, with an aperture stop interposed therebetween, in order to secure a long back focus at least three times the composite focal length of the whole system, satisfied is the following conditional expression:dx.gtoreq.3.0.times..vertline.f.sub.F .vertline. (1)wherein f.sub.

Abstract: A camera includes a device for variably focusing and condensing an image on an optical light. The camera includes a lens in which a clear liquid is disposed between opposing transparent elastic films. Pressure is externally applied to one of the films at a predetermined position, thereby changing the ratio of curvature of the transparent elastic film. This changes the focal length of the lens, thereby producing an image wherein all positions are in focus due to the persistence of vision effect of human vision.

Abstract: An inexpensive achromatic object lens for a microscope has a magnification of about 20 and a relatively long working distance. Aberrations are satisfactorily corrected even at the periphery of the image. The object lens 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 in this order from the object side. The first lens group consists of a positive lens and a cemented lens which is composed of a negative lens and a positive lens. The second lens group consists of a positive lens for converting the divergent light flux that has exited the first lens group into convergent light flux. The third lens group consists of a negative meniscus lens with its concave surface facing the image side. The object lens satisfies the conditions 4.0.ltoreq.f1/d0.ltoreq.15.0, 55.ltoreq.v2p, and 35.ltoreq.v1p-v1n.

Abstract: Provided is a microscope objective including a plurality of meniscus lenses disposed along a predetermined optical axis; a plurality of first doublets aligned along the optical axis and disposed behind the plurality of meniscus lenses; and a plurality of second doublets aligned along the optical axis and disposed behind the plurality of first doublets, wherein a distance between a rearmost one of the first doublets and a front one of the second doublets is larger than a distance between any two adjacent ones of the first doublets and a distance between any two adjacent ones of the second doublets.

Abstract: The invention is directed to a high-resolution high-apertured objective which includes an object plane (1); a first lens group (LG1); a second lens group (LG2) downstream of the first lens group; a beamsplitter (17, 18, 22, P) downstream of the second lens group; a concave mirror (21); a system diaphragm (A) interposed between the beamsplitter and the concave mirror; a third lens group (LG3); the objective defining an image plane and being configured to provide a reduction scale (.beta.) in the range of -0.4 to -0.15 and an image side numerical aperture greater than 0.5. The first and second lens groups (LG1, LG2) are configured to conjointly reduce the sine of the marginal ray angle. The reduction can be up to 40%. Preferably, the second lens group (LG2) can be configured to alone reduce the sine of the marginal ray angle. It is preferable that the sine of the marginal ray angle (sin R.sub.LG1) after the first lens group (LG1) is not less than the sine of the marginal ray angle (sin R.sub.

Abstract: An objective lens system for a microscope has a high magnification and high numerical aperture. Corrections for various aberrations, and especially coma, can be made over a wide field of view. The system can be used as an objective lens system for a fluorescence microscope. The objective lens system contains a first lens group which has multiple lenses placed in sequence as counted from the object side. The first lens group has a positive focal power. A second lens group includes a first compound lens, prepared by cementing a negative meniscus lens with its convex surface facing the object side and a biconvex lens, and a second compound lens, prepared by cementing a biconcave lens and a biconvex lens. A third lens group has multiple lenses and a negative focal power. A change in aberration can be corrected for by moving the second lens group with respect to the first and third lens groups along the optical axis. The objective lens system meets certain prescribed conditions.

Abstract: An objective unit in which illumination light is applied through an annular illumination light path surrounding lenses for guiding observation light coming from an object of observation, and which includes a shared lens for guiding the illumination light from the illumination light path to the object of observation and for guiding the observation light to the lenses.

Abstract: An objective lens system for a microscope having a power of .times.16 to .times.24 and including first, second and third lens groups, the first lens group being a comparatively thick meniscus lens component, the second lens group being a biconvex positive cemented triplet consisting of a biconvex first lens component, a biconcave second lens component and a biconvex third lens component, and a third lens group being a two lens system including a biconvex positive singlet and a negative thin meniscus lens component, or a negative and a positive thin meniscus lens components, or a positive cemented doublet, and having a relatively small number of lens elements, with its aberration (especially spherical, astigmatic difference, curvature of field and chromatic aberrations) being favorably corrected.

Abstract: A first lens group composed of at least three sheets of lenses, a second lens group composed of positive, negative, and positive lenses, and a third lens group composed of at least two sheets of lenses are successively disposed from the object side, while these lenses are made of at least two kinds of glass materials having a difference in dispersion therebetween smaller than 0.0055 and satisfy predetermined conditional expressions, thereby yielding a wide angle imaging lens with a high brightness and a wide field angle which can favorably correct various kinds of aberration, in particular, such as chromatic aberration and image surface. From the object side, the first lens group comprising, successively from the object side, a negative first lens L.sub.1, a positive second lens L.sub.2, and a negative third lens L.sub.3 ; the second lens group comprising, successively from the object side, a positive fourth lens L.sub.4, a negative fifth lens L.sub.5, and a positive sixth lens L.sub.

Abstract: An objective lens system includes a positive first lens group having a positive lens element and a negative lens element, and a positive second lens group, in this order from the object side. The objective lens system satisfies the following relationships:1.10<f.sub.1 /f<2.00,.vertline..theta.p-.theta.n.vertline.<0.02, and0.3<L/f<0.6wherein f represents the focal length of the whole lens system, f.sub.1 represents the focal length of the first lens group, .theta.p, .theta.n represent the mean values of partial dispersion ratios of the positive and negative lens elements, represented by (n.sub.g n.sub.F)/(n.sub.F -n.sub.C), respectively, and L represents the distance between the first and second lens groups.

Abstract: A plan apochromatic microscope objective lens is disclosed having few constituent lens elements, a large numerical aperture, excellent flatness across the entire field of view of the objective lens, and a relatively long working distance. The objective lens comprises, in order from the object side, first, second, and third lens groups. The first lens group comprises a meniscus lens having a concave surface oriented toward the object side, and a positive meniscus lens having a concave surface oriented toward the object side. The second lens group comprises a simple lens, a cemented lens including a negative lens and a positive lens, and a cemented lens including a positive lens and two negative lenses. The third lens group comprises a cemented lens with overall weak refractive power and including a positive lens and a negative lens. The objective lens satisfies a number of conditional expressions.

Abstract: An objective lens system for microscopes composed of only two lens components each of which is a radial type graded refractive index lens component, and having a numerical aperture of at least 0.2 and favorably corrected aberrations.

Abstract: An objective lens for an endoscope includes a first lens group having one negative lens, a second lens group having at least one positive lens, and a third lens group including a positive lens. The objective lens satisfies the following relationship:.theta..sub.g,d <-2.223.times.10.sup.-3 .cndot..nu..sub.d +1.365wherein .theta..sub.g,d =(n.sub.g -n.sub.d)/(n.sub.F -n.sub.C), n.sub.g represents the refractive index of the glass material of the first lens group at the g-line, n.sub.d represents the refractive index of the glass material of the first lens group at the d-line, n.sub.F represents the refractive index of the glass material of the first lens group at the F-line, n.sub.C represents the refractive index of the glass material of the first lens group at the C-line, and .nu..sub.d represents the Abbe number of the glass material of the first lens group.

Abstract: This invention relates to a microscope objective lens system a part of which is immersed in a liquid to observe a sample present in the liquid. Particularly, this invention provides an apochromat-grade microscope objective lens system which can be machined cheaply and easily by the conventional technology, which is well corrected for chromatic aberration, and which is excellent in flatness of the image plane. This objective lens system has a plane-parallel plate on the most sample side, is constructed without using an embedded lens as used in the conventional objectives, and can take a variety of lens layouts.

Abstract: A stereomicroscope comprising an objective lens system and eyepiece lens systems, the objective lens system comprising at least two lens units, permitting a working distance thereof by varying at least one airspace and having a concave surface at a location farthest from an object to be observed so as to minimize lowering of the magnification of the stereomicroscope and stereoscopic impressions of images observed through the stereomicroscope.

Abstract: A condenser lens system collects light from a light source to illuminate a sample, which comprises in the named order from the light source side a front group of positive refracting power having at least one lens and a rear group of positive refracting power at least having a positive lens for liquid immersion located closest to the sample and having a flat surface on the sample side.

Abstract: A wide angle lens is constituted by four sheets of concave, concave, convex, and convex lenses successively arranged from the object side so as to satisfy predetermined conditional expressions concerning focal lengths, whereby various kinds of aberration are favorably corrected and, while the cost required for molding each lens is minimized, a higher brightness can be obtained as compared with the conventional wide angle lens. From the object side, first, second, third, and fourth lenses (L.sub.1 to L.sub.4) are successively disposed. Each of the first lens (L.sub.1) and second lens (L.sub.2) is made of a negative meniscus lens whose concave surface with a stronger curvature is directed toward the imaging surface (1), while each of the third lens (L.sub.3) and the fourth lens (L.sub.4) is made of a biconvex lens whose surface with a stronger curvature is directed toward the imaging surface (1), such that f.sub.2 /f.sub.1 is 0.888 thereby satisfying a conditional expression of 0.8<f.sub.2 /f.sub.1 <1.

Abstract: A condenser lens system to collect light from a light source to illuminate a sample, which comprises in a named order from the light source side, a front group of positive refracting power having at least one lens and a rear group of positive refracting power having at least a positive lens for liquid immersion located closest to the sample, the positive lens for liquid immersion having a flat surface on the sample side.

Abstract: An objective optical system for endoscopes consisting, in order from the object side, of a front lens unit having a negative refractive power, and a rear lens unit which is composed of a single lens component and has a positive refractive power.

Abstract: An objective lens system is provided and includes a spherical sapphire lens element, an aspheric first polymeric material lens element, and an aspheric second polymeric material lens element, all of which are axially aligned. The sapphire lens element is coupled to the first polymeric material lens element to form a meniscus shaped air lens element. When inserted as a component of an endoscope, the planar surface of the sapphire lens forms a robust outer distal window at the distal end of the endoscope and the flat surface of the second polymeric material lens element is attached to the relay lens system of the endoscope. The initial image of the observed area formed at the proximal end of the objective lens system is "buried" in a higher index medium than air thus allowing for easier coupling to a relay lens system leading to lower overall f/numbers.

Abstract: A microscope objective lens, sequentially from an object-side, comprises a first lens group constructed of a positive lens element, a second lens group constructed of a negative lens element, and a third lens group constructed of cemented lens elements consisting of a negative lens element and a positive lens element and exhibiting a positive refracting power on the whole. Further, the microscope objective lens system satisfies the following conditions:1.5<f/f.sub.1 <1.9-3.8<f/f.sub.2 <3.12.0<f/f.sub.3 <2.70.9<(d.sub.2 +d.sub.3 +d.sub.4 +d.sub.5)/f.sub.1 <1.215<n.sub.1 .multidot.f/d.sub.150<n.sub.2 .multidot.f/d.sub.3wheref : the focal length of the whole system,f.sub.1 : the focal length of the first lens group,f.sub.2 : the focal length of the second lens group,f.sub.3 : the focal length of the third lens group,d.sub.1 : the central thickness of the positive lens element in the first lens group,d.sub.

Abstract: An objective lens for an endoscope includes a first lens group having one negative lens, a second positive lens group having at least one positive lens, and a third positive lens group having a cemented lens consisting of one positive lens and a negative lens adhered thereto. The objective lens satisfies the requirements defined by the following relationships:.theta..sub.g,d <-2.223.times.10.sup.-3 .multidot..nu..sub.d +1.365; and,-1.2<f.sub.1 /f<-0.8,wherein .theta..sub.g,d =(n.sub.g -n.sub.d)/(n.sub.F -n.sub.C), n.sub.g represents the refractive index of the glass material of the first lens at the g-line, n.sub.d represents the refractive index of the glass material of the first lens at the d-line, n.sub.F represents the refractive index of the glass material of the first lens at the F-line, n.sub.C represents the refractive index of the glass material of the first lens at the C-line, .nu..sub.d represents the Abbe number of the glass material of the first lens, f.sub.

Abstract: A doublet lens is optically passively athermalized by choosing two lens materials that have approximately the same Abbe number and substantially different thermal coefficients of refractive index. The ratio of the powers of the lens elements is designed to provide the desired passive athermalization. A diffractive surface is used on one of the lens elements to correct for chromatic aberration. Because the Abbe numbers are approximately the same for the two lens materials, the chromatic correction does not significantly change with temperature. This allows the ratio of the powers of the lens elements to control the focal length of the doublet with temperature being independent of chromatic correction.

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: A high resolution objective lens system for use in the ultraviolet region around 250 nm comprising in order from the object side: a first lens unit comprising a meniscus lens component having an object side concave surface having high curvature and a positive lens component, and having a positive refractive power as a whole; a second lens unit comprising at least two cemented lens components and having a positive refractive power as a whole; and a third lens unit comprising a cemented lens component and having a negative refractive power as a whole: each of the lens elements arranged in the lens units being made of an optical material which has, a thickness of at least 5 mm, and an internal transmittance of at least 50% for a ray having a wavelength of 300 nm.

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: An apochromatic microscope objective of high NA wherein variation of aberrations, including chromatic aberration, caused by a change in the cover glass thickness, is minimized with a relatively simple arrangement. The microscope objective has a 1-st lens unit (G.sub.1) which includes a positive meniscus lens having a concave surface directed toward the object side to convert a bundle of rays from an object into a convergent bundle of rays, a 2-nd lens unit (G.sub.2) having a negative refractive power, and a 3-rd lens unit (G.sub.3) having a small refractive power. The 2-nd lens unit (G.sub.2) is movable relative to the 1-st and 3-rd lens units (G.sub.1 and G.sub.3) along the optical axis in accordance with a change in thickness of a transparent plane-parallel plate disposed between the 1-st lens unit (G.sub.1) and the object. The microscope objective satisfies conditions concerning the curvature radius of a lens surface in the 1-st lens unit (G.sub.

Abstract: A stereomicroscope comprising an objective lens, an afocal vari-focal optical system disposed coaxially with the objective lens, a pair of right and left imaging optical systems for imaging parallel rays emerging from the afocal vari-focal optical system, and right and left eyepiece lens systems for magnifying images which are formed by the right and left imaging optical systems.This stereomicroscope permits observing images with adequate stereoscopic impressions and can be relatively compact owing to a fact that the microscope satisfies the following condition (1):0.005 .ltoreq.AD.multidot..beta./f.sub.0 .ltoreq.0.

Abstract: Objective lens for producing a radiation focus in the inside of a specimen. Many laser measuring methods for sensing charge carrier density or the distribution of a potential in the inside of an integrated circuit (IC) of microelectronics are based on what is referred to as "backside-probing" technique, whereby the laser radiation (LA) is focused into the plane of the voltage-carrying components (SK) from the backside of the component using a conventional microscope objective. Since the irradiation occurs through the substrate (SU), a pronounced spherical aberration arises that limits the spatial resolution to approximately 2 through 4 .mu.m. For producing a sub-.mu. probe in the substrate (SU), a lens is arranged on the polished backside (RS) of the integrated circuit (IC), this lens being composed of a silicon base plate (GP, refractive index of n.sub.1), a sphere (KU, refractive index of n.sub.2 <n.sub.1, radius of r.sub.

Abstract: An abjective lens system for microscopes consisting of a lens component having a convex surface on the image side and arranged on the extremely object side, and at least one lens component arranged on the image side of said lens component and comprising a cemented doublet. Said objective lens system for microscopes has a simple composition, consists of a small number of lens elements, and has favorably corrected spherical aberration, coma, curvature of field, etc.

Abstract: An objective lens system for use within a microscope includes a first to a fourth lenses which are spaced apart from an object side. The first lens is made of either quartz or fluorite, the second and the third lenses are made of quartz, while the fourth lens is made of fluorite. The system transmits ultraviolet and/or far ultraviolet light and correct chromatic aberration. The system is uncomplicated.

Abstract: An objective lens system for a microscope. The objective lens system includes a first lens group which includes a lens in the form of meniscus made of quartz or fluorite having a positive power; and a second lens group including a biconcave lens made of quartz and a biconvex lens made of fluorite. The first lens group and the biconcave and biconvex lenses are successively spaced apart from the object side of the system. The system transmits ultraviolet and/or far ultraviolet rays and can correct chromatic aberration. The system is uncomplicated.

Abstract: A lithography system employing a solid immersion lens having a spherical surface to enhance its resolution is disclosed.

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: An objective lens system for microscopes comprising a plurality of lens units including a first lens unit arranged at the foremost location and having a positive refractive power, and using a GRIN lens or GRIN lenses designed taking into consideration the characteristic of the glass materials currently available. The objective lens system for microscopes consists of a small number of lens elements and has favorably corrected aberrations.