Abstract: The invention provides a high-performance objective lens that is capable of implementing focusing relative to an object point distance change with no or little angle-of-view change, and is well compatible with a high-pixel type imaging device. The objective optical system comprises, in order from an object side thereof, a first group of negative power, a second group of positive power, an aperture stop, and a third group of positive power. Only the second group moves thereby implementing focusing relative to an object point distance change, with satisfaction of the following conditions (1)-1, (1)-2 and (8): ?f>60??(1)-1 ?n>60??(1)-2 ?1.2<f1/ff<?0.6??(8) where ?f is a maximum half angle of view (°) upon viewing at a far distance object point, ?n is a maximum half angle of view (°) upon close-up viewing, f1 is a focal length of the first lens group, and ff is a focal length of the whole system upon viewing at a far distance. See FIG. 1.

Abstract: Image capture lens modules are presented. An image capture lens module includes a first compound lens with a first element and a second element arranged in sequence from an object side to an image side. The second element is a plano-convex lens with a convex surface facing the image side on a paraxial line. A second compound lens includes a third element, a fourth element, and a fifth element arranged in sequence from an object side to an image side. The third element is a plano-convex lens with a convex surface facing the object side on a paraxial line, and the fifth element is a plano-concave lens with a concave surface facing the image side on a paraxial line. A third compound lens includes a sixth element and a seventh element arranged in sequence from an object side to an image side, wherein the sixth element is a plano-convex lens with a convex surface facing the object side on a paraxial line.

Abstract: A photographing optical lens assembly, sequentially arranged from an object side to an image side, comprising: the first lens element with negative refractive power having a convex object-side surface and a concave image-side surface, the second lens element with positive refractive power having bi-convex surfaces, the third lens element with positive refractive power having a convex object-side surface, at least one aspherical surface and at least one inflection point on at least one optical surface. Additionally, the photographing optical lens assembly comprises a stop and satisfies condition such as 0.75<SL/TTL<1.1, wherein SL is the axial distance from the stop to the image plane, TTL is the axial distance from the object-side surface of first lens element to the image plane. By such arrangements, the photographing optical assembly can effectively correct the aberration and obtain superior image quality.

Abstract: An image forming optical system of the present invention includes at least one cemented lens which includes a first lens element (e1), a second lens element (e2), and a third lens element (e3). The first lens element e1 is cemented to a surface on one side of the second lens element e2, and the third lens element e3 is cemented to the other surface of the second lens element e2. The first lens element e1 is a positive lens, and a combined refracting power of the second lens element e2 and the third lens element e3 is negative. The cemented lens satisfies a predetermined conditional expression.

Abstract: This invention provides a zoom lens assembly in order from an object side toward an image side including a first lens group with negative refractive power, a second lens group with positive refractive power and a third lens group with positive refractive power. The first lens group has only two lenses with refractive power from an object side toward an image side in order including a first lens with negative refractive power and a second lens with negative refractive power. The second lens group from an object side toward an image side in order includes an aperture stop, a third lens and a fourth lens. The third lens group includes a fifth lens. The number of the lens with refractive power in the zoom lens assembly is N, which satisfies the condition of 5?N?7, and the lens with refractive power in the zoom lens assembly includes at least three aspheric-surface lens.

Abstract: The present disclosure relates to a projection lens system for a projector having a spatial light modulator (SLM). The projection lens system includes, in order from the magnified end to the minified end thereof, a first lens group with negative refraction power, a second lens group with positive refraction power, and a third lens group with positive refraction power. The projection lens system satisfies the following formulas: 3<TT/f<3.6, and 0.48<BFL/f; wherein, TT is the overall length of the projection lens system; f is an effective focal length of the projection lens system; BFL is the back focal length of the projection lens system, the back focal length is equal to the distance between the third lens group and the SLM.

Abstract: This invention provides a photographing optical lens assembly comprising, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface; a second lens element with negative refractive power having a concave object-side surface and a concave image-side surface, the object-side and image-side surfaces thereof being aspheric; a third lens element having a concave image-side surface, the object-side and image-side surfaces thereof being aspheric, at least one inflection point formed on the image-side surface; wherein there are three lens elements with refractive power. Such an arrangement of lens elements can effectively reduce the total track length of the lens assembly, attenuate the sensitivity of the optical system and obtain higher resolution.

Abstract: This invention provides an imaging lens assembly including: in order from an object side toward an image side: a first lens with positive refractive power having a convex object-side surface and a convex image-side surface, a second lens with negative refractive power having at least one of its object-side surface and image-side surface being aspheric, a third lens with negative refractive power having a concave image-side surface, and both of its object-side surface and image-side surface being aspheric. An aperture stop is positioned between the first lens element and second lens element. The imaging lens assembly further comprises an electronic sensor on which an object is imaged, and there are three lens elements with refractive power.

Abstract: A zoom device for a lighting fixture has a first lens assembly of positive refractive power; a second lens assembly of negative refractive power; and a third lens assembly of positive refractive power. The first lens assembly, second lens assembly, and third lens assembly are aligned along a longitudinal axis coincident with the axis of a light beam emitted by a light source of the lighting fixture, and are characterized by respective focal lengths, which are such as to effectively adjust the size of the images projected by the lighting fixture, while at the same time maintaining compactness of the zoom device.

Abstract: An optical system includes, in order from an object side to an image side, a first lens having a negative refractive power and having a meniscus shape whose surface on the object side has a convex shape and whose surface on the image side has an aspheric shape, a second lens having a negative refractive power, and a third lens having a negative refractive power. In the optical system, a focal length of the entire optical system (f), a focal length of the first lens (f1), and respective radii of curvature of lens surfaces of the second lens on the object side and on the image side (G2R1, G2R2) satisfy the following conditions: ?1.6<f1/f<?1.2 0.1<(G2R1?G2R2)/(G2R1+G2R2)<0.5.

Abstract: There is provided an image forming optical system in which, it is possible to achieve both, the small-sizing and slimming of an optical system, and a favorable correction of various aberrations, mainly the chromatic aberration. In an image forming optical system including a lens component in which, a shape of another optical surface C of an intermediate layer L2 which is made of a transparent material having Abbe's number ?d2 which is in a close contact with one optical surface B of a lens L1 which is made of a transparent material having Abbe's number ?d1, is an aspheric shape differing from (a shape of) the optical surface B, and furthermore, a lens L3 which is made of a transparent material having Abbe's number ?d3 is in a close contact with the optical surface C, the following conditions are satisfied 0.012<1/?d3?1/?d1<0.090??(1) 0.

Abstract: A zoom lens system of the present invention has a plurality of lens units each composed of at least one lens element and, in order from the object side to the image side, comprises: a first lens unit having negative optical power and composed of two lens elements; a second lens unit having positive optical power; and a third lens unit having positive optical power, wherein in zooming, at least the first lens unit and the second lens unit move along an optical axis, on the image side relative to the second lens unit, an aperture diaphragm is arranged that moves along the optical axis integrally with the second lens unit during zooming, the second lens unit moves in a direction perpendicular to the optical axis, and the condition is satisfied: 1.00<(1?m2W)×m3W<1.50 where, Z=fT/fW>4.

Abstract: An imaging lens of which optical performance does not deteriorate even in a high temperature environment, various aberrations are well corrected, optical length is short, and back focus is sufficiently secured, comprising an aperture stop S and a junction type compound lens 14 having a positive refractive power, wherein the aperture stop and the junction type compound lens are arranged in this sequence from an object side to an image side. The junction type compound lens comprises a first lens L1, a second lens L2 and a third lens L3 arranged in this sequence from the object side to the image side. The first lens and the third lens are formed of a curable resin material, and the second lens is formed of an optical glass. The first lens and the second lens are directly bonded, and the second lens and the third lens are directly bonded. The object side face of the first lens and the image side face of the third lens are aspherical.

Abstract: An imaging optical system has, in order from an object side to an image side, a first lens group, an aperture stop, a second lens group and a third lens group. A first lens, in said third lens group, is movable along an optical axis thereby implementing focusing from a focusing-on-infinity state to a focusing-on-a-near-distance state, with satisfaction of: |f(2+3)g/f1g|<1??(1) ?6.0<(R3gr+R3gf)/(R3gr?R3gf)<3.5??(2) where f(2+3)g is the combined focal length of the second lens group and the third lens group upon focusing on infinity; f1g is the focal length of the first lens group; R3gr is the axial radius of curvature of the surface of the most image side of a negative lens component of the third lens group; and R3gf is the axial radius of curvature of the surface of the most object side of said lens component of the third lens group.

Abstract: A telescope that provides for simultaneous clear viewing of objects or areas at various distances may be either Galilean or astronomical. The telescope may be mounted on or into any mechanism or device used for targeting or aiming. Such devices may include iron sights of small arms weapons, and cameras and telescopes, which may be either electrically or manually focused. These miniature scopes are engineered to maximize the clear depth-of-field viewing by the eye regardless of vision irregularities, such as Presbyopia, Myopia, Hyperopic, Astigmatism, or combinations of these, in conjunction with or without spectacle lens corrections. This aiming scope/device may be placed on a pair of spectacles in a very close proximity to the eye cornea. Other maximized scope image characteristics that occur are field-of-view, luminosity, and unmagnified and unbroken or distorted viewing field.

Abstract: A projection lens comprises, from a long conjugate side to a short conjugate side, a first lens unit with positive optical power, a second lens unit with negative optical power, and a third lens unit with negative optical power. The first lens unit is configured for correcting chromatic aberration of the projection lens. The third lens unit comprises a meniscus lens which is convex toward to the short conjugate side of the projection lens.

Abstract: The imaging lens includes, in order from the object side, a first lens having positive refractive power, a second lens having positive refractive power, and a third lens having negative refractive power. The first lens is provided with a substrate portion which is a parallel plate, and a lens portion formed of a material having a refractive index different from that of the substrate portion on at least one of the object-side surface or the image-side surface of the substrate portion, and the second lens is a single lens and satisfies the following conditional expression: 1<f2/f<20, wherein f2 represents the focal length of the second lens and f represents the focal length of the entire imaging lens system.

Abstract: Various embodiments provide an optical system including a first lens group having a plurality of lenses, the first lens group being configured to correct for an axial chromatic aberration; a second lens group having a least one lens, the second lens group being disposed adjacent the first lens group; and a third lens group having a plurality of lenses, the third lens group being configured to correct for a lateral chromatic aberration and field curvature, the third lens group being disposed adjacent the second lens group. The first, second and third lens groups are configured to provide a wide field of view greater than approximately 20 deg., and an f-number of less than approximately F/2 in a wavelength range between approximately 8 ?m and approximately 12 ?m.

Abstract: A projection lens disposed between an enlarged side and a reduced side and including a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having positive refractive power, and an optical element disposed between the second and the third lens groups is provided. The first lens group includes a first and a second lens sequentially arranged from the enlarged side to the reduced side and respectively having a positive and a negative refractive power. The second lens group between the first lens group and the reduced side includes a third, a fourth, a fifth, and a sixth lens sequentially arranged from the enlarged side to the reduced side. The fifth and the sixth lens respectively have a positive refractive power. The third lens group disposed between the second lens group and the reduced side includes a seventh lens.

Abstract: The invention provides an imaging optical system comprising, in order from an object side to an image side thereof, a first lens group of positive refracting power, a second lens group having positive or negative refracting power and a third lens group of positive refracting power. The optical system includes an aperture stop located between an object-side surface in the first lens group and an object-side surface in the second lens group. The lens on the most object side of the first lens group and the lens on the most image side of the third lens group remain constantly fixed, and upon focusing from a far distance to a near distance, only the second lens group moves axially. The third lens group comprises a front lens subgroup of positive refracting power located on the object side and a rear lens subgroup of negative refracting power located on the image side, with the largest axial air separation in the third lens group interposed between them.

Abstract: A zoom lens system includes a negative first lens group, a positive second lens group and a positive third lens group, in this order from the object. The second lens group includes a cemented lens having a positive first lens element and a negative second lens element, and a meniscus lens element having the concave surface facing toward the image. The zoom lens system satisfies the following conditions: ?0.4<f23/f24<0.4??(1) 0.7<f3/ft<1.3??(2) wherein f23: the combined focal length of the cemented lens; f24: the focal length of the meniscus lens element; f3: the focal length of the third lens group; and ft: the focal length of the zoom lens system at the long focal length extremity.

Abstract: It is preferable that an image forming optical system includes in order from an object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a negative refractive power, and a subsequent lens group having a positive refractive power as a whole, and that the third lens group includes only a cemented lens having a negative refractive power, which includes a positive lens and a negative lens in order from the object side. Moreover, it is preferable that a cemented surface of the cemented lens in the third lens group has a shape which is convex toward an image side.

Abstract: An imaging lens includes a first group having a positive or negative refractive power, a second group having a positive refractive power, a third group having a positive or negative refractive power, which are sequentially arranged from the object side of the imaging lens. The first group includes an aperture stop, and the second group includes a positive lens, and a cemented lens of a positive lens and a negative lens. The third group is composed of a cemented lens of a positive lens and a negative lens, and the following formula (1) is satisfied: 0.5?f2/f?1.2??(1), where f: focal length of the entire system of the imaging lens, and f2: focal length of the second group.

Abstract: An optical lens system for taking image comprises three lens elements with refractive power, from the object side to the image side: a first lens element with positive refractive power, a second lens element with negative refractive power having at least one aspheric surface, a third lens element with negative refractive power having at least one aspheric surface, and an aperture stop located between the first lens element and the second lens element. By such arrangements, it can effectively reduce the volume and the sensitivity of the lens system.

Abstract: A zoom lens includes a first lens unit with a negative refractive power, a second lens unit with a positive refractive power, and a third lens unit with a positive refractive power in order from the object side to the image side. The first lens unit includes a negative lens and a positive lens. When the curvature radius of the object side surface and that of the image side surface of the negative lens are respectively defined as R11 and R12 and the curvature radius of the object side surface and that of the image side surface of the positive lens are respectively defined as R21 and R22, the following conditional expression is satisfied: ?5.6<(R12+R21)/(R12?R21)<?4.7 and 1.5<(R11+R22)/(R11?R22)<2.3.

Abstract: Image capture lens modules are presented. An image capture lens module includes a first compound lens with a first element and a second element arranged in sequence from an object side to an image side. The second element is a plano-convex lens with a convex surface facing the image side on a paraxial line. A second compound lens includes a third element, a fourth element, and a fifth element arranged in sequence from an object side to an image side. The third element is a plano-convex lens with a convex surface facing the object side on a paraxial line, and the fifth element is a plano-concave lens with a concave surface facing the image side on a paraxial line. A third compound lens includes a sixth element and a seventh element arranged in sequence from an object side to an image side, wherein the sixth element is a plano-convex lens with a convex surface facing the object side on a paraxial line.

Abstract: An achromatic refractive beam shaping optical system that transforms the intensity distribution of a light beam, preferably provides transformation of a beam which intensity distribution described by Gaussian function to a beam of uniform intensity. The system consists of at least two lens groups, one of lens groups is made from at least two lenses having different characteristics, of spectral dispersion, thus achromatic for a certain spectral range optical design providing zero or negligible for practical applications wave aberration is realized. By choosing parameters of lens groups the system can be realized as a telescope of Galilean or Keplerian type, or as a collimator, or as an objective lens. To provide adjustment features one lens group of the system is movable along the optical axis.

Abstract: An miniature three-piece optical imaging lens with short back focal length, along an optical axis from the object side to the image side including: a first lens of positive refractive power that is a meniscus aspherical lens having a convex surface on the object side, an aperture stop, a second lens of negative refractive power that is a meniscus aspherical lens having a convex surface on the image side, a third lens of negative refractive power that is an aspherical lens whose center is on the optical axis, while on the lens center the convex surface is on the object side and the concave surface is on the image side. Moreover, from the center of the third lens element toward the edge, the refractive power changes from negative power, through an inflection point, to positive power. Furthermore, the optical imaging lens further satisfies conditions: 0.25 ? bf TL ? 0.4 wherein bf is back focal length, TL is total distance on the optical axis from the object side of the first lens to the image plane.

Abstract: An imaging lens includes a first lens L1 having positive curvature radii on both an object side and an image side, a second lens L2 having a concave shape on both sides, and a third lens L3 having positive curvature radii on both the object side and the image side. The first to third lenses L1 to L3 are arranged in this order from the object side toward the image side. When the first lens L1 has a focal length f1 and the second lens L2 has a focal length f2, the imaging lens is configured such that a relationship f1>|f2| is satisfied.

Abstract: The present invention is an imaging lens of which optical performance does not deteriorate even in a high temperature environment, various aberrations are well corrected, optical length is short, and back focus is sufficiently secured, the imaging lens comprising a first junction type compound lens, an aperture stop S, a second junction type compound lens, and a third junction type compound lens, which are arranged in this sequence from an object side to an image side. The first junction type compound lens comprises a first lens L1, a second lens L2 and a third lens L3 arranged in this sequence from the object side to the image side, the second junction type compound lens comprises a fourth lens L4, a fifth lens L5 and a sixth lens L6 arranged in this sequence from the object side to the image side, and the third junction type compound lens comprises a seventh lens L7, an eighth lens L8 and a ninth lens L9 arranged in this sequence from the object side to the image side.

Abstract: The invention provides a high-performance objective lens that is capable of implementing focusing relative to an object point distance change with no or little angle-of-view change, and is well compatible with a high-pixel type imaging device. The objective optical system comprises, in order from an object side thereof, a first group of negative power, a second group of positive power, an aperture stop, and a third group of positive power. Only the second group moves thereby implementing focusing relative to an object point distance change, with satisfaction of the following conditions (1)-1, (1)-2 and (8): ?f>60??(1)-1 ?n>60??(1)-2 ?1.2<f1/ff<?0.6??(8) where ?f is a maximum half angle of view (°) upon viewing at a far distance object point, ?n is a maximum half angle of view (°) upon close-up viewing, f1 is a focal length of the first lens group, and ff is a focal length of the whole system upon viewing at a far distance. See FIG. 1.

Abstract: In an imaging lens, one compound lens and two single lenses are arranged in a lens barrel. On the light output side of the lens barrel, a filter is arranged with a distance from lens barrel. With a further distance from the filter, an imaging element is arranged. In the compound lens, a resin lens is bonded to a base member lens, having an output surface center of the resin lens displaced by a prescribed amount relative to an output surface center of the base member lens, so that a transmission decentration amount attributed to the base member lens, not including the resin lens, and the single lenses is cancelled by a transmission decentration amount by the resin lens when taken as a whole lens system. Thus, the imaging lens capable of suppressing reduction in resolving power due to transmission decentration of the lenses is obtained.

Abstract: The present invention provides a photographing optical lens assembly comprising, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface and a concave image-side surface; a second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, the object-side and image-side surfaces thereof being aspheric; and a third lens element with negative refractive power having a convex object-side surface and a concave image-side surface, the object-side and image-side surfaces thereof being aspheric and at least one inflection point being formed on the image-side surface, wherein the lens assembly is further provided with a stop disposed between an object and the first lens element.

Abstract: Provided is an imaging lens, including, in order from an object side: a positive first lens; a second lens having a concave shape toward the object side; and (i?2) number of lens, wherein the i-th lens, which is the most image-side lens, includes: an i-th lens flat plate; and a positive or negative lens element on at least one of the opposite surfaces of the i-th lens flat plate, wherein the following conditional relationship is satisfied: 0.9>Ymax/Y>0.61, where: Ymax is a height of the most off-axial ray on an image-side surface of the (i?1)th lens; and Y is a maximum image height.

Abstract: The invention relates to an eyepiece optical system that, albeit being of small size, works in favor of gaining an angle of field and optical performance, and an electronic view finder incorporating such an eyepiece optical system. Specifically, the invention is characterized by comprising, in order from an object side to an exit side thereof, a first lens group that is a single lens that has positive refracting power and is in a meniscus configuration concave on its object side, a second lens group that is a single lens that has negative refracting power and is in a meniscus configuration concave on its object side, and a third lens group that is a single lens that has positive refracting power, wherein an object-side concave lens surface in the first lens group is an aspheric surface, an object-side concave lens surface in the second lens group is an aspheric surface, and an exit-side lens surface in the third lens group is an aspheric surface.

Abstract: Providing a zoom lens system having excellent optical performance, an optical apparatus, and a method for zooming the zoom lens system. The zoom lens system includes, in order from an object, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, and a third lens group G3 having negative refractive power. Upon zooming from a wide-angle end state W to a telephoto end state T, each distance between adjacent lens groups is varied. The second lens group G2 includes, in order from the object, a front group G2a having positive refractive power, and a rear group G2b. Focusing on the object is carried out by moving the front group G2a along an optical axis. Given conditional expressions are satisfied.

Abstract: An imaging lens system includes three lens groups having four lenses including a first lens, a second lens, a third lens, and a fourth lens arranged in order from an object side, and an aperture stop arranged between the first lens and the second lens. The second lens and the third lens are joined each other. The first lens is a negative meniscus lens having a convex surface at an object side. The second lens is a positive lens having a convex surface having a large curvature at an image side. The third lens is a negative lens having a concave surface having a large curvature at an object side. The fourth lens is a positive lens having a convex surface having a large curvature at an image side. The following conditions are satisfied: 1.4<|f1/F|<2.2 0.4<|f1/f23|<1.6 where F is a focal length of the entire imaging lens system, f1 is a focal length of the first lens, and f23 is a combined focal length of the second lens and the third lens which are joined each other.

Abstract: This invention provides a photographing optical lens assembly including, in order from an object side to an image side: a first lens element with positive refractive power; a second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, the object-side and image-side surfaces thereof being aspheric; and a third lens element with negative refractive power having a concave object-side surface, a concave image-side surface and at least one inflection point formed on the third lens element, the object-side and image-side surfaces thereof being aspheric. The first lens element may be a bi-convex lens element or a convex-concave meniscus lens element. When the first lens element is a bi-convex lens element, the refractive power thereof may be significantly enhanced to shorten the total track length of the optical system. When the first lens element is a meniscus lens element, the astigmatism of the optical system may be better corrected.

Abstract: Providing an optical system having excellent optical performance with sufficiently correcting spherical aberration and curvature of field, an imaging apparatus, and a method for forming an image by the optical system. The optical system includes a plurality of lens groups, at least one of the plurality of lens groups having an A lens that satisfies at least one of given conditional expressions.

Abstract: A front projection display device includes an optical engine including an illumination system, an imaging system, and projection optics. The projection optics include a first lens group of negative refractive power that has at least one aspheric surface. The projection optics output an image at a half field angle of at least 45°, where the image has substantially no distortion. For example, when the first lens group is placed at a distance of less than 1 meter from a viewing screen, the output image has a size of about 40 inches diagonal or greater, and requires substantially no keystone correction. In other aspects, the optical engine can be implemented in a wall-mounted projection system, a multimedia system, a compact integrated monitor system, and a portable projection unit.

Abstract: An optical lens system for taking image comprises, in order from the object side to the image side: an aperture stop; a first lens element with positive refractive power having a convex object-side surface and a convex image-side surface; a plastic second lens element with negative refractive power having a concave object-side surface, a convex image-side surface and at least one aspheric surface; a plastic third lens element with negative refractive power having a convex object-side surface, a concave image-side surface and at least one aspheric surface. The number of the lens elements with refractive power being limited to three. Focal lengths of the optical lens system, the first lens element, the second lens element and the third lens element are f, f1, f2, f3 respectively; Abbe numbers of the first and second lens elements are V1, V2 respectively, an on-axis distance between second and third lens elements is T23, and they satisfy the relations: 0.8<f/f1<1.8; 0<|f/f2|<0.8; 0<|f/f3|<0.

Abstract: An imaging lens unit which achieves a lower profile without adversely affecting the optical performance. The imaging lens unit includes a first lens, an aperture stop, a second lens, and a third lens arranged sequentially along the optical axis from the object side to the image side. The first lens includes a first surface located on the object side and being convex toward the object side and a second surface located on the image side and being concave toward the image side near the optical axis and convex toward the image side as the rim of the first lens becomes closer.

Abstract: An image pickup lens includes, in order from an object side thereof: a first lens; a second lens comprising a surface facing the image surface side of the image pickup lens which is an aspheric surface; and a third lens. The aspheric surface has a concave shape facing the image surface side at a paraxial portion and has a convex shape facing the image surface side at the periphery.

Abstract: A zoom eyepiece lens system EL includes, in order from an eyepoint EP side: a first lens group G1 having positive refractive power; a second lens group G2 having positive refractive power; and a third lens group G3 having negative refractive power. Upon zooming from a low magnification end state to a high magnification end state, the second lens group G2 and the third lens group G3 move along an optical axis in opposite directions with each other. The second lens group G2 includes, in order from the eyepoint EP side, a first lens L3 having negative refractive power, a second lens L4 having positive refractive power, and a third lens L5 having positive refractive power. At least one aspherical surface is formed on the third lens L5.

Abstract: An optical lens system for taking image comprises three lens elements with refractive power, from the object side to the image side: a first lens element with positive refractive power, a second lens element with negative refractive power having at least one aspheric surface, a third lens element with negative refractive power having at least one aspheric surface, and an aperture stop located between the first lens element and the second lens element. By such arrangements, it can effectively reduce the volume and the sensitivity of the lens system.

Abstract: An imaging lens of which various aberrations are corrected well, optical length is short, and back focus is sufficiently secured, is provided. The imaging lens is formed of a first lens L1, an aperture stop S, a second lens L2 and a third lens L3, arranged in this sequence from the object side to the image side. The first lens L1 is a meniscus lens having a positive refractive power, of which convex surface faces the object side, the second lens L2 is a meniscus lens having a positive or negative refractive power, of which convex surface faces the image side, and the third lens L3 is a meniscus lens having a negative refractive power, of which convex surface faces the object side. The Abbe number ? of the second lens L2 is a value in a 50.0 to 60.0 range.

Abstract: A wide-angle lens optical system, including, in a sequence from an object side, a first lens group having a positive or negative refractive power, a stop, and a second lens group having positive refractive power, wherein the first lens group comprises, in a sequence from the object side, a front group having negative refractive power and a rear group having positive refractive power, and the wide-angle lens optical system satisfies the following Inequalities: 1.0 < f II f < 1.45 0.6 ? ? f Ia f Ib ? < 1.5 where f denotes the overall focal distance of the lens optical system, fII denotes the focal distance of the second lens group, fIa denotes the focal distance of the front group of the first lens group, and fIb denotes the focal distance of the rear group of the first lens group.

Abstract: An objective lens system for endoscope comprising at least a first negative lens element, a second positive lens element, an aperture stop, and a cemented lens component consisting of a third negative lens element and a fourth positive lens element, and being configured so as to satisfy the conditions (2), (5) and (4) or the conditions (2), (3) and (4) which are mentioned below, whereby the lens system corrects lateral chromatic aberration and longitudinal chromatic aberration with a good balance, favorably corrects aberrations such as chromatic aberration and has a compact composition or a short total length. D2/f<0.9??(2) |f/(f1×?1)+f/(f2×?2)|<0.025??(5) 1.5<|(f4×?1)/(f3×?3)|??(4) |f/(f5×?5)?f/(f1×?1)?f/(f2×?2)|<0.025.

Abstract: The present invention is an imaging lens of which optical performance does not deteriorate even in a high temperature environment, various aberrations are well corrected, optical length is short, and back focus is sufficiently secured, the imaging lens comprising a first lens 14, an aperture stop S, a second lens 16, and a third lens 18, which are arranged in this sequence from an object side to an image side. For the first lens, a single lens is used. The second lens comprises a first sub-lens L1, a second sub-lens L2 and a third sub-lens L3, arranged in this sequence from the object side to the image side. The third lens comprises a fourth sub-lens L4, a fifth sub-lens L5 and a sixth sub-lens L6, arranged in this sequence from the object side to the image side. The first lens is formed of a transparent curable silicone resin, and the first, third, fourth and sixth sub-lenses are also formed of the transparent curable silicone resin.

Abstract: Disclosed are a projection lens that is faster than F1.95 and has a simple inner focus structure, a high optical performance, and a small size, and a projection display device. A projection lens includes a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power arranged in this order from a magnification side. A fifth lens arranged closest to a reduction side in the first lens group is moved along an optical axis to adjust focus. The projection lens satisfies the following conditional expression: 0.2<DG12/f<0.8 where DG12 indicates a distance between the first lens group and the second lens group and f indicates the focal length of the entire lens system.