Abstract: An optical system is provided. In order from an object side to an image side, the optical system includes a first lens element having a positive power, a meniscus shape, and an object side surface. The object side surface of the first lens element is convex toward the object side. A second lens element has a negative power, a meniscus shape, and an object side surface. The object side surface of the second lens element is concave toward the object side. A third lens element has a positive power. An aperture stop is positioned on or in front of an object side of the first lens element.

Abstract: This application discloses a lens system comprising in order from an object side to an image side: an aperture stop; a first lens element, having a positive optical power; and a second lens element, having a negative optical power. By setting the shapes of the respective lens elements and the materials making up the respective lens elements so as to meet predetermined conditions in such a lens system, a lens system of a compact size which provides good optical performance is realized while securing telecentric characteristics.

Abstract: The present invention includes, from the object side to the image plane side, an aperture stop with a predetermined diameter, a first lens with a positive refractive power and a bi-convex shape with convex surfaces facing the object side and the image plane side, a second lens being formed as a meniscus shape with a concave surface facing the object side having a negative refractive power, and a third lens being formed as a meniscus shape with a convex surface facing the object side having a positive refractive power. By having a positive refractive power for the first lens and third lens and a negative refractive power for the second lens, a suitable back focus can be maintained while reducing the total length of the lens system. The imaging lens is thin and compact and has superior optical properties suited for mobile cameras mounted in portable telephones and PDAs.

Abstract: A lens system has a plurality of lenses, a stop, and a diffractive surface, the entire lens system moves during focusing, and the lens system satisfies the condition of ??0.5, where ? is a maximum photographic magnification.

Abstract: An imaging lens for an image pickup device is formed of only three lens components of positive, negative, and positive refractive power, in order from the object side. A diaphragm stop is positioned on the object side of the lens component nearest the object side. Six lens component lens surfaces are aspheric. The lens component nearest the object side is biconvex with regard to the central areas of its two lens surfaces. The image-side surface of the lens component nearest the image side has a concave central area surrounded by a convex surface area. The middle lens component has one lens surface with a concave central area and one lens surface with a convex central area. The Abbe number of the central lens element and the ratio of the focal length of the imaging lens divided by the focal length of the object-side lens component satisfy specified conditions.

Abstract: A bright, small, and inexpensive imaging lens system is provided with a short total length that can provide more than a 30 degree viewing angle and whose aberrations are excellently corrected. The imaging lens includes, in order from an object side, a positive first lens with a convex surface facing the object side, an aperture stop provided on the object side or an image side of the first lens, a meniscus second lens with a concave surface facing the object side, and a meniscus third lens with a convex surface facing the object side. Furthermore, at least one of the first lens and the second lens includes an aspheric surface, and the third lens is a biaspheric lens. In addition, the second lens and the third lens have paraxial focal lengths whose signs are different. When v max and v min are the maximum Abbe number and the minimum Abbe number among the lenses, respectively, the condition, 1.25<v max/v min, is satisfied.

Abstract: A single focus lens includes, in order from the object side: a first lens component of positive refractive power with a convex surface on the object side; a diaphragm stop; a second lens component that is made of plastic, has at least one aspheric surface and a meniscus shape, and has a concave surface on the object side near the optical axis; and, a third lens component of positive refractive power with two aspheric surfaces, one of which is convex on the object side near the optical axis. Each lens component that forms the single focus lens may consist of a lens element. Specified conditions are satisfied in order to reduce aberrations, to insure that the light rays at the image plane are substantially orthogonal to the image plane, and to insure that a sufficient back focus is provided to allow for insertion of other optical elements.

Abstract: An imaging optical system comprising, in order from the object side, a first positive meniscus lens having a convex surface on the object side, an aperture stop, a second negative meniscus lens having a convex surface on the image side, and a third positive lens having an object side aspherical surface which has curvature lowered toward a marginal portion of the aspherical surface and an image side surface which has curvature enhanced toward the marginal portion of the aspherical surface. This imaging optical system allows its performance to be degraded due to manufacturing errors and exhibits high performance even when the optical system is configured compact.

Abstract: The subject invention relates to broadband optical metrology tools for performing measurements of patterned thin films on semiconductor integrated circuits. Particularly a family of optical designs for broadband, multi-wavelength, DUV-IR (185<?<900 nm) all-refractive optical systems. The designs have net focusing power and this is achieved by combining at least one positively powered optical element with one negatively powered optical element. The designs have small spot-size over the wavelength range spanning 185-900 nm with substantially reduced spherical aberration, axial color, sphero-chromatism and zonal spherical aberration. The refractive optical systems are broadly applicable to a large class of broadband optical wafer metrology tools including spectrophotometers, spectroscopic reflectometers, spectroscopic ellipsometers and spectroscopic scatterometers.

Abstract: An optical magnifier is provided. One general form of one example embodiment includes two lens elements, at least two aspheric surfaces, and at least one diffractive surface. Another general form of another example embodiment includes three lens elements, and at least three aspheric surfaces. At least two of the aspheric surfaces can be simple conics. The optical magnifier, suitable for use in an electronic display system, has an apparent field of view of at least +/?10 degrees; a magnification of at least 15×; a back focal length of at least 5 mm; and an eye relief greater than the effective focal length of the optical magnifier. The lens elements can be made from plastic.

Abstract: A large numerical aperture objective lens is disclosed having three lens groups. In order from the object side, these lens groups include: a first lens group of positive refractive power that is formed of two positive lens elements and an achromatic set of paired lens elements formed of a lens element of negative refractive power and a lens element of positive refractive power, respectively; a second lens group of negative refractive power; and a third lens group of positive refractive power, with the surface of the third lens group nearest the object side being convex. Specified conditions are satisfied in order to provide a compact, large numerical aperture objective lens having its aberrations favorably corrected as well as to correct for shifts of focus caused by expansion/contraction of the lens barrel with changes in temperature.

Abstract: This application discloses a lens system comprising in order from an object side to an image side: an aperture stop; a first lens element, having a positive optical power; and a second lens element, having a negative optical power. By setting the shapes of the respective lens elements and the materials making up the respective lens elements so as to meet predetermined conditions in such a lens system, a lens system of a compact size which provides good optical performance is realized while securing telecentric characteristics.

Abstract: An imaging optical system comprising, in order from the object side, a first positive meniscus lens having a convex surface on the object side, an aperture stop, a second negative meniscus lens having a convex surface on the image side, and a third positive lens having an object side aspherical surface which has curvature lowered toward a marginal portion of the aspherical surface and an image side surface which has curvature enhanced toward the marginal portion of the aspherical surface. This imaging optical system allows its performance to be degraded due to manufacturing errors and exhibits high performance even when the optical system is configured compact.

Abstract: An imaging lens for an image pickup device is formed of only three lens components of positive, negative, and positive refractive power, in order from the object side. A diaphragm stop is positioned on the object side of the lens component nearest the object side. Six lens component lens surfaces are aspheric. The lens component nearest the object side is biconvex with regard to the central areas of its two lens surfaces. The image-side surface of the lens component nearest the image side has a concave central area surrounded by a convex surface area. The middle lens component has one lens surface with a concave central area and one lens surface with a convex central area. The Abbe number of the central lens element and the ratio of the focal length of the imaging lens divided by the focal length of the object-side lens component satisfy specified conditions.

Abstract: The invention relates to a fast macro lens that is well corrected for aberrations even at close range, and a camera comprising the macro lens. The macro lens comprises, in order from its object side, a first lens group G1 having positive power and a second lens group G2 having positive power. In the first lens group G1 a negative meniscus lens component concave on its object side is located nearest to the object side of the macro lens. Upon focusing from an object point at infinity to the closest object point, the first G1 and the second lens group G2 move independently toward the object side of the macro lens while the spacing between them varies.

Abstract: A lens system includes a plastic positive lens, a plastic negative lens and a glass positive lens. The plastic lenses are made to be meniscus lenses and an aspheric surface and a diffractive surface are respectively mounted onto the plastic lenses so as to have better image with low manufacturing cost.

Abstract: A single-focus lens includes from the object side, a first lens with a positive refracting power having at least one aspheric surface, a stop, a second lens with a negative refracting power, and a third lens with a positive refracting power having at least one aspheric surface. This single-focus lens further satisfies the conditional expression of 0.3<f/f2′3<0.8, where f is the focal length of the lens as a whole, and f23 is the composite focal length of the second and third lenses.

Abstract: A lens system includes a plastic positive lens, a plastic negative lens and a glass positive lens. The plastic lenses are made to be meniscus lenses and an aspheric surface and a diffractive surface are respectively mounted onto the plastic lenses so as to have better image with low manufacturing cost.

Abstract: An image readout lens is formed of three lens groups of positive, positive, and negative refractive power, in order from the object side, with a stop between the second and third lens groups. The first lens group is convex on the object side, the second lens group is made of an optical resin material that is convex on the object side, and the third lens group is made of an optical resin material that is convex on the image side. At least one surface among the surfaces of the second and third lens groups is aspheric, and various conditions are satisfied so as to provide an image readout lens that is small in size, low in cost, provides a sufficiently wide field of view for wide applicability in scanning documents, and has its aberrations favorably corrected so as to enable the image readout lens to scan color documents.

Abstract: A lens having a long focal length that is suitable for photography with a large film size is disclosed having three lens groups of positive, negative, and positive refractive power, in order from the object side, as follows: a first lens group having a positive refractive power and formed of, in order from the object side, one or two positive lens element(s), a negative lens element, and a positive lens element; a second lens group having a negative refractive power and formed of, in order from the object side, a negative lens element and a positive lens element; and a third lens group having a positive refractive power and formed of, in order from the object side, a positive lens element, a negative lens element, and a positive lens element. Focusing is performed by moving the second lens group as one unit along the optical axis.

Abstract: The subject invention relates to broadband optical metrology tools for performing measurements of patterned thin films on semiconductor integrated circuits. Particularly a family of optical designs for broadband, multi-wavelength, DUV-IR (185<&lgr;<900 nm) all-refractive optical systems. The designs have net focusing power and this is achieved by combining at least one positively powered optical element with one negatively powered optical element. The designs have small spot-size over the wavelength range spanning 185-900 nm with substantially reduced spherical aberration, axial color, sphero-chromatism and zonal spherical aberration. The refractive optical systems are broadly applicable to a large class of broadband optical wafer metrology tools including spectrophotometers, spectroscopic reflectometers, spectroscopic ellipsometers and spectroscopic scatterometers.

Abstract: A single-focus lens comprises, successively from the object side, a first lens with a positive refracting power having at least one aspheric surface, a stop, a second lens with a negative refracting power, and a third lens with a positive refracting power having at least one aspheric surface. This single-focus lens further satisfies the conditional expression of 0.3<f′/f′23<0.8, where f′ is the focal length of the lens as a whole, and f′23 is the composite focal length of the second and third lenses.

Abstract: An image pickup lens system comprises a first lens which has a concave face formed on the side of an object in the vicinity of an optical axis, and which has a positive power, a diaphragm, a second lens having a negative power, and a third lens having a positive power. The first lens, the diaphragm and the second and third lenses are disposed sequentially from the side of the objects. If the image pickup lens system is formed in the above manner, a desired optical performance can be maintained, and a sufficient back focal length can be ensured, while a high telecentric property can be ensured. Moreover, various aberrations can be corrected satisfactorily, and the image pickup lens system can be produced easily.

Abstract: An image readout lens is formed of three lens groups of positive, positive, and negative refractive power, in order from the object side, with a stop between the second and third lens groups. The first lens group is convex on the object side, the second lens group is made of an optical resin material that is convex on the object side, and the third lens group is made of an optical resin material that is convex on the image side. At least one surface among the surfaces of the second and third lens groups is aspheric, and various conditions are satisfied so as to provide an image readout lens that is small in size, low in cost, provides a sufficiently wide field of view for wide applicability in scanning documents, and has its aberrations favorably corrected so as to enable the image readout lens to scan color documents.

Abstract: A bright wide-angle infrared lens, suitable for a wavelength band of 8 to 12 &mgr;m, having favorable imaging performances comprises, successively from the object side, a first lens L1 made of a positive meniscus lens having a convex surface directed onto the object side and an image-side surface formed aspheric, a second lens L2 made of a negative meniscus lens having a convex surface directed onto the object side, and a third lens L3 having a positive refracting power with a convex surface directed onto the object side.

Abstract: A lens system is particularly designed for use in an image reading device, essentially including three lenses elements, wherein two or three of them are plastic lenses.

Abstract: An image pickup lens system according to the present invention includes a diaphragm, a first lens which has a convex fact formed on the side of an image surface in the vicinity of an optical axis and which has a positive power and radii of curvature at a center, whose signs are not opposite from each other, a second lens which has a convex face formed on the side of an object in the vicinity of the optical axis and which has a negative power and radii of curvature at a center, whose signs are not opposite from each other, and a third lens which has a convex face formed on the side of the image surface in the vicinity of the optical axis and which has a positive power. The diaphragm and the first, second and third lenses are disposed sequentially from the side of the object, and the first face of at least the second lens being formed into an aspherical shape.

Abstract: A double-wavelength aperture restricting filter has a zonal part adapted to act such that one wavelength &lgr;1 of light keeps the quantity of light in an outer peripheral part of the luminous flux thereof whereas the other wavelength &lgr;2 of light apparently extinguishes this quantity of light by an interference effect. The zonal part has such a step that light supposed to pass a position corresponding to the zonal part if the zonal part does not exist and light passing a position at which the zonal part is formed if the zonal part exists generate therebetween a phase difference satisfying predetermined conditional expressions, whereas the circle formed by a step boundary has a diameter residing between two luminous flux diameters desired in two systems used for the wavelengths &lgr;1 and &lgr;2, respectively.

Abstract: An image reader including a light source irradiating light to a reading object, a reading device reading an image on the reading object based on the radiated light; and a lens focusing the image onto the reading device and having a characteristic by which a distortion rate is increased from the central part to the end part. The distortion rate of the end part is set to a value in which there is no need to complement the read image.

Abstract: A wide-angle zoom lens includes a front lens unit with positive refracting power and a rear lens unit with negative refracting power so that spacing between the front lens unit and the rear lens unit is changed to thereby vary the magnification of the zoom lens.

Abstract: A telephoto lens system includes a positive first lens group, a negative second lens group and a positive third lens group.

Abstract: In a lens system for focusing a divergent beam in a small spot and comprising a collimator lens and an objective lens, the collimator lens is composed of a positive plastics lens element and a negative glass lens element. This collimator corrects the temperature-dependent spherical aberration of the objective lens. This lens system is very suitable for a scanning device and an apparatus for reading/writing high-density optical discs.

Abstract: The internal focusing telephoto lens includes a first lens group I of positive refractive power, a second lens group II of negative refractive power and a third lens group III of positive refractive power, arranged in order from an object side. The second lens group II is movable along an optical axis for focusing. The first lens group I includes a first positive lens I-1, a second positive meniscus lens I-2 whose object side surface is convex, a third positive meniscus lens I-3 whose object side surface is convex and a fourth negative meniscus lens I-4 whose object side surface is convex, in order from the object side. At least two of the first positive lens I-1, the second positive meniscus lens I-2 and the third positive meniscus lens I-3 in the first lens group I satisfy the following conditions (1) and (2); 1.55<nI<1.75  (1) 61<&ngr;I  (2) where nI is refractive index and &ngr;I is Abbe number of the lenses in the first lens group I.

Abstract: An image readout lens comprises, successively from the object side, a first lens L1 made of a positive meniscus lens having a convex surface directed onto the object side, a second lens L2 made of a biconcave lens having a surface with a greater curvature directed onto the object side, and a third lens L3 made of a biconvex lens having a surface with a greater curvature directed onto the image side, the first lens L1 and second lens L2 each being a plastic lens with aspheric surfaces on both sides. The image readout lens satisfies the following conditional expressions (1) and (3) to (5): 0.08<D6/F<0.2  (1) 1.5<|R6|/F<2.2  (3) 0.5<R2/F<1.55   (4) 0.5<R4/F<1.2  (5) where D6 is the center thickness of the third lens, Rj (j=1 to 7) is the radius of curvature of the j-th surface from the object side, and F is the focal length of the whole lens system.

Abstract: An objective optical system comprising, in order from the object side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power and a third lens unit having a positive refractive power, wherein the second lens unit is moved along an optical axis for changing a magnification. This objective optical system is configured to be compact and have favorable optical performance by adequately selecting an airspace between the first lens unit and the second lens unit as well as a power for the first lens unit.

Abstract: In a three-lens configuration, the first lens is formed into a biconvex lens, the third lens is formed into a positive meniscus lens having a concave surface directed onto the object side, and the refractive index distribution of the refractive index distribution type second lens is defined by a predetermined conditional expression, whereby various kinds of aberration are made favorable even when used for reading out images at a magnification near 1:1, while achieving wider angle of view, higher performances, and compactness. An imaging lens for copying to be used at a magnification near 1:1 comprises the first lens L.sub.1 having a biconvex form, the second lens L.sub.2 having a biconcave form with a refractive index distribution along the optical axis direction, and the third lens L.sub.3 made of a positive meniscus lens having a concave surface directed onto the object side, whereas a stop i is disposed between the second lens L.sub.2 and the third lens L.sub.3. The refractive index of the second lens L.

Abstract: In a three-sheet image readout lens, predetermined expressions are satisfied, so as to yield a bright lens system which can favorably correct each kind of aberration, while attaining a smaller size and a lighter weight. The lens system is constituted by, successively from the object side, three positive, negative, and positive lenses L.sub.1 to L.sub.3, while a stop i is disposed downstream the third lens L.sub.3, satisfying the following conditional expressions (1) to (6):(1) 0.85<f.sub.1 /f<0.93(2) -0.90<f.sub.2 /f.sub.3 <-0.84(3) 0.025<d.sub.2 /f<0.043(4) 0.09<d.sub.5 /f<0.16(5) -2.5<r.sub.3 /r.sub.4 <-2.1(6) .vertline.d.sub.6 .vertline./f.ltoreq.0.03.

Abstract: A zoom lens has, in succession from the object side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, and a third lens unit having positive refractive power. The second and third lens units are moved to thereby effect zooming. When variations in the magnifications of the second and third lens units from the wide angle end to the telephoto end are Z.sub.2 and Z.sub.3, respectively, the zoom lens satisfies the condition that Z.sub.3 /Z.sub.2 >1.4. The zoom lens is compact and yet covers a wide angle range of an angle of view of 60.degree.-80.degree..

Abstract: A triplet lens system composed of a first positive lens element, a second negative lens element and a third positive lens element. At least one lens surface is provided with a blazed zonal structure having a function of a positive diffractive lens.

Abstract: A photographic apparatus includes, in order from an object side to an image side, a positive first lens of meniscus shape convex toward the object side made from plastic, a negative second lens of bi-concave shape made from plastic, a positive third lens of bi-convex shape made from glass material, and a stop, wherein the following conditions are satisfied:0.8<f1/f<1.18 (1)0.95<(td+sk)/f<1.12 (2)where f1 and f are focal lengths of the first lens and the entire photographic lens, respectively, td is a distance from a lens surface on the object side of the first lens to a lens surface on the image side of the third lens, and sk is a back focal distance during focusing on an infinitely distant object.

Abstract: A first lens made of a positive meniscus lens having a convex surface directed onto the object side, a second lens made of a biconcave lens, and a third lens made of a biconvex lens are successively disposed from the object side, and predetermined conditional expressions are satisfied, thus yielding an image readout imaging lens suitable for reading out the shorter side of A4--sized color originals and the like. Successively from the object side, a first lens L.sub.1 made of a positive meniscus lens having a convex surface directed onto the object side, a second lens L.sub.2 made of a biconcave lens, and a third lens L.sub.3 made of a biconvex lens are disposed, and the following conditional expressions (1) to (5) are satisfied:-0.36f<f.sub.2 <-0.25f (1)-1.07<f.sub.2 /f.sub.3 <-0.74 (2)0.26f<r.sub.4 <0.32f (3)0.43<r.sub.4 /r.sub.5 <0.77 (4)0.82<r.sub.1 /r.sub.4 <1.

Abstract: A close-up attachment lens, for enabling close-up photograph along with a main lens, is arranged to be attached to the object side of said main lens. The close-up attachment lens comprises, in that order from the object side, a positive first lens element, a negative second lens element, and a positive third lens element formed as a meniscus lens that is convex on the image side. Furthermore, the close-up attachment lens satisfies the following conditions:0.005<d2/fA<0.040 (1)0.010<(d2+d4)/fA<0.060 (2)wherein:di designates the distance between the ith surface and (i+1).sup.th surface;fA designates the focal length of the attachment lens.

Abstract: A lens system composed of a first lens unit which is composed of at least a positive lens component and at least a negative lens component, and a second lens unit which comprises at least one positive lens component. The lens system is composed of a small number of lens components and configured to be compact by disposing at least one radial type gradient index lens component in the second lens unit and selecting an adequate refraction index distribution for the radial type gradient index lens component.

Abstract: The focal length of an objective lens system is substantially equal at two wavelengths: one within the visible spectrum and one within an eyesafe IR spectrum centered about 1.54 .mu.m; the lens is essentially achromatic throughout the entire visible spectrum (0.45 .mu.m -0.70 .mu.m) and is well-corrected for other monochromatic aberrations (spherical aberration, coma, astigmatism, field curvature, and distortion). By having an objective lens that is common to both optical paths (visual and laser) and has the property of having essentially the same focal length and essentially the same angular deviation for the two optical paths upon lens decentration, then a practical mechanism can be included in the opto-mechanical design of a laser rangefinder to adjust the x and y decentration of the objective lens to accomplish a corresponding x and y adjustment of the system boresight.

Abstract: An athermalized and achromatized optical system (10, 30) has a lens group (12, 32) focusing energy on a focal plane (14, 42). The lens group (12, 32) includes at least two optical elements (22, 24, 26, 34, 36) of different material and a diffractive optical element (28, 40). The system (10, 30) enables athermalization and achromatization of the optical system.

Abstract: A triplet lens system comprising, in order from the object side, a first positive meniscus lens component having a convex surface on the object side, a second biconcave lens component, a third biconvex lens component and a stop; and configured so as to correct aspherical aberration and coma at the same time by using at least one aspherical surface on the second and the third lens components.

Abstract: A Cooke triplet projection lens for use in overhead projectors comprises two outer positive elements of an ophthalmic crown glass and one inner negative element of a light flint glass. The crown glass has a refractive index of roughly 1.523 and an Abbe value of 58.5. The flint has an index of less than 1.573 and an Abbe value of between 43 and 53. One of the positive elements is biconvex; the other is meniscus.

Abstract: A collimator lens system for collimating diverging light bundle emitted from a light source into a parallel light bundle includes first to third lens elements arranged in this order from the side of the parallel light bundle. The first lens to third elements are a positive double-convex lens, a negative lens concave to the side of the parallel light bundle and a positive lens convex to the side of the parallel light bundle, respectively. The following formulae (1) to (5) are satisfied0.8<f.sub.1 /f.sub.3 <2.0 (1)1.5<{r.sub.2 (n.sub.2 -1)}/{r.sub.3 (n.sub.1 -1)}<2.7 (2)0.8<r.sub.5 /{f(n.sub.3 -1)}<1.4 (3)0.8<-r.sub.1 /r.sub.2 <2.4 (4)0.5<-f.sub.2 /f<6.0 (5)wherein f represents the overall focal length of the collimator lens system, f.sub.i represents the focal length of i-th lens element, i standing for 1, 2 or 3, r.sub.i represents the radius of curvature of i-th refracting surface as numbered from the side of the parallel light bundle, i standing for 1, 2, 3, 4, 5 or 6 and n.

Abstract: A compact objective lens with a diaphragm arranged behind the lens system suitable for use in very compact photographic cameras. The objective lens comprises a plurality of components arranged in a triplet or a triplet type configuration and is capable of covering at least a 55 degree field of view.

Abstract: A compact objective lens system with a diaphragm arranged in front of or preferably behind the lens system and suitable for use in compact photographic cameras. The objective lens comprises a plurality of components arranged in a triplet-type configuration that are capable of covering at least a 55 degree field of view and utilizes the locations of aperture stop, the lens bendings, and the size of lens elements, clear apertures of the lens element surfaces to enhance the lens system performance and to eliminate stray light problems.