Abstract: An optical lens includes a first lens group and a second lens group. The first lens group is disposed between a magnified side and a minified side and has a negative refractive power. The second lens group is disposed between the first lens group and the minified side and has a positive refractive power. The optical lens is capable of forming an image at the magnified side. F/H>0.52, where F is an effective focal length, and H is an image height. A viewing angle is greater than 116.7 degrees.

Abstract: Provided is an endoscope objective optical system 1 including, in order from an object side, a first lens 2 composed of a negative single lens, a second lens 3 composed of a positive single lens, an aperture stop 4, a third lens 5 composed of a positive single lens, and a fourth lens 6 composed of a positive combined lens, wherein the third lens 5 has a meniscus shape having a convex surface facing the image side. The endoscope objective optical system (1) satisfies the following conditions: 0.3<Df/f<1.15,??(1) n1<1.79,??(2) n2>n1,??(3) 0.6<IH/f<0.83,??(4) and |r1|?|r2|+d1>1.

Abstract: A variable-magnification projection optical system substantially consists of a negative first lens group that is disposed at the most enlargement-side position and is fixed during magnification change, a positive last lens group that is disposed at the most reduction-side position and is fixed during magnification change, and a plurality of lens groups that are disposed between the first lens group and last lens group and are moved during magnification change. The most enlargement-side lens group (the second lens group) of the lens groups that are moved during magnification change has a negative refractive power. Predetermined conditional expressions relating to a back focus of the entire system on the reduction side at the wide-angle end, a focal length of the entire system at the wide-angle end, a focal length of the second lens group and a focal length of the last lens group are satisfied.

Abstract: A variable-magnification projection optical system substantially consists of a negative first lens group that is disposed at the most enlargement-side position and is fixed during magnification change, a positive last lens group that is disposed at the most reduction-side position and is fixed during magnification change, and a plurality of lens groups that are disposed between the first lens group and last lens group and are moved during magnification change. The lens groups that are moved during magnification change substantially consist of three lens groups, wherein the most enlargement-side lens group is a negative lens group. Predetermined conditional expressions relating to a back focus of the entire system on the reduction side at the wide-angle end, a focal length of the entire system at the wide-angle end, a focal length of the last lens group, and a focal length of the first lens group are satisfied.

Abstract: A wide-angle lens is disclosed. The wide-angle lens includes a first lens element L1, a second lens element L2, a third lens element L3, an aperture diaphragm S, a fourth lens element L4 and a fifth lens element L5 arranged from an object plane to an image plane. The first element L1 is a meniscus lens element having a negative focal power and protruding toward the object plane, the second element L2 is a meniscus lens element having a negative focal power and protruding toward the object plane, the third element L3 is a meniscus lens element having a positive focal power and protruding toward the image plane, the fourth element L4 is a meniscus lens element having a negative focal power and protruding toward the object plane, and the fifth element L5 is a lens element having a positive focal power.

Abstract: The imaging lens substantially consists of a first lens having a biconvex shape, a second lens having a negative refractive power, a third lens having a negative refractive power and a convex surface that faces the object side, a fourth lens having a positive refractive power, and a fifth lens having a negative refractive power, of which at least one of the object-side surface and the image-side surface has at least one inflection point, in this order from the object side; and wherein conditional expression (1A): ?0.38<f/f45<?0.01 is satisfied. This conditional expression is related to the focal length f of the entire system and the combined focal length f45 of the fourth lens and the fifth lens.

Abstract: An imaging lens includes a lens barrel having a base wall with a light incident hole around an optical axis, an imaging unit disposed in the lens barrel and including imaging components arranged along the optical axis, and a light shielding plate having an annular fixing portion for positioning the light shielding plate and a bent portion bent from an inner periphery of the fixing portion and extending slantingly toward the optical axis. The light shielding plate is disposed at one of a position between the base wall and one of the imaging components that is adjacent to the base wall, and a position between two adjacent ones of the imaging components.

Abstract: An exemplary embodiment of the present invention relates to an imaging lens, the imaging lens including, in an ordered way from an object side, a first lens having positive (+) refractive power, a second lens having negative (?) refractive power, a third lens having positive (+) refractive power, a fourth lens having negative (?) refractive power, and a fifth lens having a negative (?) refractive power, wherein the third lens takes a meniscus shape convexly formed at an object side.

Abstract: An optical unit and an image pickup unit are provided that allow a full angular field to be increased in spite of small size and low cost. An image pickup lens 100 has a first lens 111 with a positive power, a second lens 113 with a positive power, a third lens 114 with a positive power, and a fourth lens 115 with a negative power that are arranged in order from an object side OBJS toward an image surface side, that are arranged in order from the object side toward the image surface side.

Abstract: A telephoto lens system including a first lens group having a positive refractive power and including a negative lens that is disposed closest to an object side and has a meniscus shape that is convex toward the object side; a second lens group having a negative refractive power and including a single negative lens that moves along an optical axis and performs focusing; and a third lens group having a positive refractive power, wherein the first through third lens groups are disposed sequentially from the object side toward the image side, and the telephoto lens system satisfies the following condition, 0.5<|f2/f|<0.81, wherein, f2 denotes the focal length of the second lens group, and f denotes the focal length of the telephoto lens system.

Abstract: An image pickup lens includes: in recited order from object plane toward image plane, a first lens having positive refractive power; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens having positive or negative refractive power; a fifth lens having positive refractive power; and a sixth lens having negative refractive power and having optical surfaces, one or more of the optical surfaces each having an aspherical shape with one or more inflection points.

Abstract: An optical imaging lens set includes: a first lens element, an aperture stop, a second lens element, a third lens element, a fourth lens element and a fifth lens element, the first lens element with refractive power having a convex object-side surface and an image-side surface with a concave part in a vicinity of its periphery, the second lens element with refractive power having an object-side surface with a convex part in a vicinity of its periphery, the third lens element with refractive power having an object-side surface with a concave part in a vicinity of its periphery, the fourth lens element with refractive power, the fifth lens element with refractive power having an image-side surface with a concave part in a vicinity of the optical axis.

Abstract: The endoscope objective lens is configured such that focusing from the farthest object to the nearest object is achieved by moving at least one lens group other than the most object-side lens group along the optical axis. One of the at least one lens group to be moved during focusing is a negative lens group. The one negative lens group that is moved during the focusing consists of a cemented lens that is formed by a positive lens and a negative lens cemented together in this order from the object side. The cemented surface of the cemented lens is oriented such that the concave surface faces the object side. Given conditional expressions are satisfied.

Abstract: A zoom lens 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, a fourth lens group having a positive refractive power, a fifth lens group having a positive refractive power, and a last lens group having a positive refractive power. At the time of zooming from a wide angle end to a telephoto end, the second lens group and the third lens group move, and one of the fourth lens group, the fifth lens group, and the last lens group moves.

Abstract: An imaging lens substantially includes six lenses, constituted by: a first lens having a positive refractive power and a convex surface that faces an object side; a second lens having a negative refractive power; a third lens having a positive refractive power; a fourth lens having a positive refractive power; a fifth lens having a negative refractive power and a concave surface that faces the object side; and an aspherical sixth lens having a negative refractive power, the surface of which is concave toward an image side in the vicinity of an optical axis and convex toward the image side at the peripheral portion thereof. The imaging lens satisfies a predetermined conditional formula.

Abstract: An imaging lens substantially includes six lenses, constituted by: a first lens having a negative refractive power, which is of a meniscus shape having a concave surface toward an image side; a second lens; a third lens; a fourth lens; a fifth lens having a positive refractive power; and a sixth lens having a negative refractive power, a concave surface toward the image side, and at least one inflection point in the surface toward the image side; provided in this order from an object side. The imaging lens satisfies a predetermined conditional formula.

Abstract: An imaging lens includes a first lens element, an aperture stop, and second to fifth lens elements arranged from an object side to an image side in the given order. Through designs of surfaces of the lens elements and relevant optical parameters, a short system length of the imaging lens may be achieved while maintaining good optical performance.

Abstract: Present embodiments provide for a mobile device and an optical imaging lens thereof. The optical imaging lens comprises five lens elements positioned sequentially from an object side to an image side. Though controlling the convex or concave shape of the surfaces and/or the refracting power of the lens elements, the optical imaging lens shows better optical characteristics and the total length of the optical imaging lens is shortened.

Abstract: A zoom lens includes a first lens unit, a second lens unit, a third lens unit and a fourth lens unit that includes a 41 lens group and a 42 lens group. The 41 lens group includes a 411 lens group and a 412 lens group. A lens surface on a most image side of the 411 lens unit has a shape convex to the image side and a lens surface on the most object side of the 412 lens unit has a shape concave to the object side. A curvature radius r411 of the lens surface on the most image side of the 411 lens unit, a curvature radius r412 of the lens surface on the most object side of the 412 lens unit, and lateral magnification ?3w of the third lens unit at a wide-angle end are respectively appropriately set.

Abstract: In a zoom lens including a positive first lens unit, negative second lens unit, positive third lens unit, and positive fourth lens unit, the fourth lens unit includes a 41 lens group, a 42 lens group, and a 43 lens group. the lateral magnification of the third lens unit at a wide-angle end when an infinite object is focused, the focal length of the fourth lens unit, the lens configuration length of the fourth lens unit, the air interval between the 41 and 42 lens groups, the air interval between the 42 and 43 lens groups, the focal length of the 42 lens group, the average values of the Abbe constants and partial dispersion ratios of positive lens of the 42 lens group, the average values of the Abbe constants and partial dispersion ratios of negative lenses of the 42 lens group, and the like are appropriately set.

Abstract: An imaging lens assembly comprises a fixing diaphragm and an optical set including five lenses. An arranging order from an object side to an image side is: a first lens; a second lens; a third lens having a lens with a positive refractive power defined near the optical axis and a convex surface directed toward the image side; a fourth lens having a lens with a positive refractive power defined near the optical axis and a convex surface directed toward the image side; and a fifth lens having a concave surface with a corrugated contour directed toward the image side and disposed near the optical axis. At least one surface of the five lenses is aspheric. By the concatenation between the lenses and the adapted curvature radius, thickness, interval, refractivity, and Abbe numbers, the assembly attains a big diaphragm with ultra-wide-angle, a shorter height, and a better optical aberration.

Abstract: A miniature image pickup lens includes a first lens, a second lens, an aperture, a third lens, a fourth lens, and a fifth lens arranged in sequence along an optical axis from an object side to an image side. The first lens is a negative meniscus lens with a convex surface towards the object side and a concave surface towards the image side. The second lens is a positive lens with a convex surface towards the object side. The third lens is a positive biconvex lens, and the fourth lens is a negative biconcave lens. The fifth lens has a convex surface towards the object side.

Abstract: A zoom lens includes a positive first lens group fixed during zooming, a negative second lens moved to the image side upon zooming from the wide angle end to the telephoto end, a negative third lens group for image plane correction during zooming, and a positive fourth lens group fixed during zooming. The first lens group is composed of a negative first lens group front group, a positive first lens group middle group, and a positive first lens group rear group, disposed in order from the object side. The first lens group front group is composed of two negative lenses and one positive lens, disposed in order from the object side. Focusing is performed by moving only the first lens group middle group in an optical axis direction. The zoom lens satisfies a predetermined conditional expression.

Abstract: A wide field optically athermalized orthoscopic lens system includes, in order from object to image, a first lens having a negative power, a second lens having a positive power, a third lens group having a positive power, a fourth lens having a positive power and a fifth lens having a negative power. The third lens group includes two lenses having, in order, a first lens with positive power and a second lens with negative power. The powers, shapes, Abbe dispersion values and temperature coefficients of refractive indices of the lenses are selected such that the lens system is athermalized, orthoscopic and achromatized over a wide (e.g. >140° C.) temperature range.

Abstract: A zoom lens includes: a first lens group having a negative power; and a second lens group having a positive power, in this order from an object side. The first lens group includes a first lens having a negative power and a second lens having a positive power. The zoom lens satisfies conditional formulae 1.6<|f1|/fw<2.5 (1); 1.6<f2/fw<2.4 (2); 0.32<d2/fw<0.60 (3); 2.5<ft/fw<4.5 (4); 1.56<nd2<1.66 (5); and ?d2<33 (6), when f1: the focal length of the first lens group, f2: the focal length of the second lens group, fw: the focal length of the entire system at the wide angle end, d2: the distance between the first and second lenses along an optical axis, ft: the focal length of the entire system at the telephoto end, nd2: the refractive index of the second lens at the d line, and ?d2: the Abbe's number of the second lens at the d line.

Abstract: An imaging lens system has, from an object side, at least one positive lens element convex to the object side, a negative lens element, and at least one lens element having an aspherical surface. The positive and negative lens elements are arranged next to each other. The formulae 0.1<Ton/Dopn<7, 0.1<(Rona?Ronb)/(Rona+Ronb)<1.5, and 0.3<Y?/TL<0.

Abstract: An imaging lens substantially includes six lenses, constituted by: a first lens having a negative refractive power; a second lens having a positive refractive power; a third lens having a positive refractive power; a fourth lens having a negative refractive power; a fifth lens having a positive refractive power; and a sixth lens having a negative refractive power, a concave surface toward an image side, and at least one inflection point in the surface toward the image side; provided in this order from an object side. The imaging lens satisfies a predetermined conditional formula.

Abstract: The imaging lens substantially consists of a front group having positive refractive power, an aperture stop, a rear group having positive refractive power in this order from the object side. The front group substantially consists of a lens having a negative meniscus shape with a convex surface toward the object side, a negative lens, and a positive lens in this order from the object side. The rear group substantially consists of a positive lens, a negative lens, a positive lens, and a positive lens in this order from the object side. In the case that the Abbe numbers with respect to the d-line of the first lens and the second lens from the object side in the front group are respectively ?1 and ?2, conditional expressions (1) and (2) below are satisfied: 10.0<?2??1??(1) 40<?2??(2).

Abstract: An imaging device with a short length and small aberration is provided. A total length D of an image-forming optical system is less than 3.6 mm. A maximum incidence angle of a principle ray on an image forming plane exceeds 33°. Conditions f/fL<?1.50 or f/fL<?0.9, and D/f<1.10 are satisfied where f denotes a focal length of the entire image-forming optical system and fL denotes a focal length of a last lens.

Abstract: The zoom lens includes a front unit including a first positive lens unit and a second positive or negative lens unit, a reflective mirror and a rear unit including two or more lens units. During zooming, the reflective mirror is not moved, and the first lens unit and at least two lens units of the rear unit are moved. When the zoom lens is retracted into a body of an image pickup apparatus, at least one of rotation of the reflective mirror such that a normal line thereto is brought closer to parallel to an optical axis of the rear unit and axial movement thereof in a direction of the optical axis of the rear unit is performed. The front unit is moved into a space formed by the at least one of the rotation and the axial movement. Conditions of 10.5<ft/|fn|<30.0 and 0.80<(Lf?L)/Lm<1.30 are satisfied.

Abstract: An optical image capturing lens assembly includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, and a sixth lens element. The first lens element with positive refractive power has an object-side surface being convex in a paraxial region. The second lens element with negative refractive power has an object-side surface being concave in a paraxial region and an image-side surface being convex in a paraxial region. The third lens element has refractive power. The fourth lens element with refractive power has an object-side surface being convex in a paraxial region. The fifth lens element with positive refractive power has an image-side surface being convex in a paraxial region. The sixth lens element with refractive power has an image-side surface being concave in a paraxial region.

Abstract: An imaging lens substantially consists of six lenses of a negative first lens, a negative second lens, a positive third lens, a positive fourth lens, a negative fifth lens and a positive sixth lens in this order from an object side. An object-side surface of the second lens has a shape having negative refractive power at a center, and including a part having positive refractive power in an area between the center and an effective diameter edge, and having negative refractive power at the effective diameter edge (concave shape facing the object side), and the refractive power at the effective diameter edge being weaker than the refractive power at the center. Further, an object-side surface of the third lens is convex toward the object side. Further, a predetermined conditional formula about a combined focal length of the first lens, the second lens and the third lens is satisfied.

Abstract: An imaging lens assembly comprises a fixing diaphragm and an optical set including five lenses. An arranging order from an object side to an image side is: a first lens; the fixing diaphragm; a second lens; a third lens; a fourth lens; and a fifth lens. At least one surface of the five lenses is aspheric. By the concatenation between the lenses and the adapted curvature radius, thickness/interval, refractivity, and Abbe numbers, the assembly attains a big diaphragm with wide-angle, a shorter height, and a better optical aberration.

Abstract: This super-wide lens substantially consists of a positive first lens group, a positive second lens group, and a negative third lens group, in this order from the object side. The first lens group and the third lens group are fixed and the second lens group moves toward the object side while focusing from an object at infinity to an object at the closest distance. The first lens group substantially consists of a negative first sub lens group, a positive second sub lens group, an aperture stop, and a positive third sub lens group in this order from the object side. Conditional expressions (1) and (2) are satisfied: 0.15<f1/f2<0.60??(1) 2.5<f2/f<7.0??(2), where f1: the focal length of the first lens group, f2: the focal length of the second lens group, and f: the focal length of the entire system when focusing on an object at infinity.

Abstract: A single-focal-length imaging lens system achieves focusing by, while keeping first and third lens groups stationary relative to the image plane, moving a second lens group along the optical axis. The second lens group includes a positive lens element. The third lens group includes an aspherically shaped lens element having an inflection point at a position other than the intersection with the optical axis. The first and second air lenses formed by the intervals between the first and second and between the second and third lens groups have negative and positive refractive powers respectively. The conditional formula 0?|Fi1/Fi2|?|Fm1/Fm2|?10 is fulfilled (Fi1 and Fi2 representing the focal lengths of the first and second air lenses, respectively, when focusing on the infinite object distance; Fm1 and Fm2 representing the focal lengths of the first and second air lenses, respectively, when focusing on the closest object distance).

Abstract: A zoom lens comprises, in order from its object side, a first lens unit having a negative refractive power and a second lens unit having a positive refractive power. The first lens unit comprises a first lens having a negative refractive power and a second lens having a positive refractive power. The zoom lens satisfies the following conditional expressions (1), (2), and (3): n1n?1.70??(1), n1p?1.70??(2), and |?1n??1p?31??(3), where n1n is the refractive index of the first lens having a negative refractive power in the first lens unit for the d-line, ?1n is the Abbe constant of the first lens having a negative refractive power in the first lens unit, n1p is the refractive index of the second lens having a positive refractive power in the first lens unit for the d-line, and ?1p is the Abbe constant of the second lens having a positive refractive power in the first lens unit.

Abstract: A zoom lens includes, in order from an object side to an image side: a positive first lens unit; a negative second lens unit; a positive third lens unit; and a positive fourth lens unit, wherein the first lens unit includes a positive first lens subunit, which does not move for focusing, a positive second lens subunit, which moves during the focus adjustment, and a positive third lens subunit, which does not move for focusing; and focal lengths of the first lens unit, the second lens unit, the third lens unit, a magnification of the third lens unit U3 at a wide angle end, focal lengths of the first lens subunit, the second lens subunit appropriately satisfy certain relations.

Abstract: There is provided a zoom lens including, in order from an object side to an image side, a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power. In zooming from a wide-angle end to a telescopic end, the first lens group moves to the object side in a manner that a distance toward the second lens group shortens, and a distance between the third lens group and the fourth lens group lengthens. The third lens group includes a single lens or a single cemented lens.

Abstract: Low ghosting wide-angle lens designs are presented. The dimensions and materials are selected such that the lens has a field of view of at least 145 degrees, f# of 2.2-2.9 and all secondary images of an object imaged on the image plane are focused such that they fall either outside of the image plane thus having a relative intensity that is less than 10?4 times the intensity of the primary image. In one embodiment a set of conditional expressions are all met. In another embodiment the conditional expressions are all met and the conditional expressions related to the physical size of the lens is narrowed. In another embodiment five and seven element designs are produced.

Abstract: A telephoto lens system includes a first lens group having a positive refractive power, and comprising at least three positive lenses and one negative lens; a second lens group having a negative refractive power, and which moves along an optical axis to perform a focusing operation; a third lens group having a positive refractive power, and comprising a cemented lens in which a positive lens having a convex surface toward the object side and a positive lens having a convex surface toward the image side are bonded to each other, a bi-convex positive lens, and a negative lens having a concave surface toward the object side, and the first through third lens groups are disposed sequentially from the object side to the image side.

Abstract: A zoom lens system has, in order from the enlargement side, a first lens group that remains stationary during zooming and that has a negative optical power and a plurality of lens groups that move during zooming. The first lens group includes three lens groups each having a negative optical power, namely a 1a-th lens group, a 1b-th lens group, and a 1c-th lens group. The 1a-th lens group remains stationary during focusing and includes at least one positive lens element. The 1b-th lens group moves toward the reduction side during focusing from infinity to a close distance. The 1c-th lens group moves toward the enlargement side during focusing from infinity to a close distance.

Abstract: A lens optical system includes first, second, third, fourth, and fifth lenses that are arranged between an object and an image sensor where an image of the object is formed, in order from an object side, wherein the first lens has a positive (+) refractive power and an incident surface that is convex toward the object, the second lens has a negative (?) refractive power and a meniscus shape that is convex toward the object, the third lens has a positive (+) refractive power and both convex surfaces, the fourth lens has a positive (+) refractive power and a meniscus shape that is convex toward the image sensor, and the fifth lens has a negative (?) refractive power and an incident surface and an exit surface, at least one of the incident surface and the exit surface is an aspherical surface.

Abstract: A zoom lens includes first to third lens units having positive, negative, and positive refractive power, respectively, and a rear lens group having positive refractive power. An aperture stop is arranged between a lens surface of the second lens unit closest to the image side and a lens surface of the third lens unit closest to the image side. The third lens unit includes first and second positive lenses each including an aspheric surface, and a negative lens. In the third lens unit, a refractive index of the first positive lens, and an Abbe number and relative partial dispersion of the second positive lens are appropriately set.

Abstract: A photographing lens assembly includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element. The positive first lens element has a convex object-side surface. The second and the third lens elements have refractive power. The fourth lens element has positive refractive power. The negative fifth lens element has a convex object-side surface, a concave image-side surface, and at least one inflection point on at least one surface thereof, wherein the surfaces of the fifth lens element are aspheric. The negative sixth lens element has a concave image-side surface and at least one inflection point on at least one surface thereof, wherein the surfaces of the sixth lens element are aspheric. The photographing lens assembly has a total of six lens elements with refractive power.

Abstract: To provide an image pickup lens with a five-lens configuration in which aberrations are corrected favorably despite its compactness. An image pickup lens 10 includes a first lens L1 having a positive refractive power and having a convex face directed to an object side, a second lens L2 of a meniscus shape having a negative refractive power and having a concave face directed to an image side, a third lens L3 having a positive refractive power, a fourth lens L4 having a positive refractive power and having a convex face directed to the image side, and a fifth lens L5 having a negative refractive power and having a concave face directed to the image side, in this order from the object side. Here, the focal length of the fifth lens, the focal length of the entire system of the image pickup lens, and an air separation on an optical axis between the fourth lens and the fifth lens satisfy predetermined conditions.

Abstract: A wide angle lens system and an electronic apparatus including the same are provided. The wide angle lens system includes a first lens group having a negative refractive power, and a second lens group having a positive refractive power. The second lens group is spaced apart from the first lens group by a maximum air gap. The first lens group and the second lens group are sequentially arranged from an object side toward an image side. The second lens group includes a positive 2-1 lens group, a negative 2-2 lens group, and a positive 2-3 lens group, and focusing is performed by moving the 2-2 lens group along an optical axis.

Abstract: An imaging-lens substantially consists of a first-lens-group, a stop and a second-lens-group in this order from object-side. The first-lens-group substantially consists of three or less lenses including a negative-lens having meniscus-shape with convex-surface facing object-side and a positive-lens cemented on the negative-lens in this order from object-side. The second-lens-group substantially consists of a 21st-lens-group substantially consisting of a 21-1st-lens and a 21-2nd-lens and a 22nd-lens-group substantially consisting of a positive-lens. The 21-1st-lens is a positive-lens, an image-side-lens-surface of which has convex-shape facing image-side, and the absolute-value of a curvature-radius of the image-side-lens-surface of which is less than the absolute-value of a curvature-radius of an object-side-lens-surface thereof.

Abstract: To off-axis and on-axis aberrations at low cost while having a wide angle of view, an endoscope objective optical system (1) has in order: a negative first lens (L1); a negative second lens (L2) and a third lens (L3) joined to each other; a brightness diaphragm (S); and a positive lens group (G2) having a cemented lens (CL2) including one positive lens and one negative lens joined to each other, and satisfies expressions (1) and (2): 1.0<D3(96 deg)/f_all<10 ??(1) 1.1<(r1+r2)/(r1?r2)<5.0 ??(2) where, D3(96 deg) is a distance in which a chief ray of a d-line having an incident angle of 96 degrees that enters the first lens transmits the third lens, f_all is a focal distance of the whole system, r1 and r2 are radii of curvature of an object side surface of the first lens and an image side surface of the second lens, respectively.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens having positive refractive power; a fifth lens having negative refractive power; and a sixth lens having negative refractive power. The first lens has an object-side with a positive curvature radius. The second lens has object-side and image plane-side surfaces with positive curvature radii. The third lens has an image plane-side surface with a negative curvature radius. The fourth lens has object-side and image plane-side surfaces with negative curvature radii. The fifth lens has object-side and image plane-side surfaces with negative curvature radii. The sixth lens has strong positive refractive power close to a periphery, and an aspheric image plane-side surface having an inflexion point. The first to sixth lenses have specific Abbe's numbers to satisfy specific conditions.

Abstract: An optical module (10) comprises a positive meniscus lens (16) having a focal length F1 and comprising a first convex optical surface (12) and a second concave optical surface (20), and a plano-convex lens (22) having a focal length F1 and comprising a third flat optical surface (24) and a fourth convex optical surface (26) from an object side (12) to an image side (14). The curvatures of the four optical surfaces (12, 20, 24, 26) are defined by the equation: Zi=CURViYi2/(1+(1+Ki)CURVi2Yi2)½)+(Ai)Yi2+(Bi)Yi4+(Ci)Yi6+(Di)Yi8, and the two lenses are defined by 0.35<F1/F2<0.90, 0.30<Conv2/Conv<0.70, and 0.50<M1/M2<1.