37results about How to "Excellently corrected" patented technology

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.

A zoom lens system having a high zoom ratio and excellently correcting various aberrations over an entire zoom range between a wide angle end and a telephoto end to obtain high optical performance in the entire zoom range, includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit, and a fourth lens unit. The fourth lens unit includes a front subunit and a rear subunit, the rear subunit being constituted by two negative lenses and at least three positive lenses. The rear subunit includes a first rear-subunit and a second rear-subunit. Each of the first rear-subunit and the second rear-subunit includes a negative lens and at least one positive lens. Lens materials are suitably set for the first rear-subunit and the rear second-subunit.

A variable magnification optical system includes a positive first lens group, a negative second lens group, a stop, a positive third lens group and a positive fourth lens group, which are in this order from an object side. The first lens group, the stop and the third lens group are fixed, but the second lens group and the fourth lens group move in an optical axis direction during magnification change. The fourth lens group has a focusing function. The third lens group includes at least an aspherical surface, and consists of, in the following order from the object side, a positive lens and a cemented lens of a positive lens and a double-concave lens cemented together. The variable magnification optical system satisfies a predetermined formula.

A projection zoom lens includes, from an image side to an object side, a first lens group having a negative refractive power, consisting of a number of lens elements and being movable along the optical axis of the projection zoom lens; a second lens group having a positive refractive power, consisting of a number of lens elements and being movable along the optical axis of the projection zoom lens; and an aperture stop arranged between two lens elements of the second lens group and being axially movable therewith.

A rear attachment lens changes a focal-length of an entire lens-system, in which the rear attachment lens has been attached to a main-lens, to a longer focal-length-side than a focal-length of the main-lens by being attached to an image-side of the main-lens. The rear attachment lens consists essentially of a first-lens-group and a second-lens-group in this order from an object-side. The first-lens-group consists essentially of a negative lens and a positive lens in this order from the object-side. The second-lens-group consists essentially of at least one negative lens and at least one positive lens, and a lens closest to an image-side in the second lens-group is a positive lens. When an Abbe number for d-line and a partial dispersion ratio between g-line and F-line of the negative lens in the first-lens-group are νd1 and θgF1, respectively, conditional expression (1): νd1>62 and conditional expression (2): 0.64<θgF1+0.001625 ×νd1<0.69 are satisfied.

A zoom lens system having a high zoom ratio and excellently correcting various aberrations over an entire zoom range between a wide angle end and a telephoto end to obtain high optical performance in the entire zoom range, includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit, and a fourth lens unit. The fourth lens unit includes a front subunit and a rear subunit, the rear subunit being constituted by two negative lenses and at least three positive lenses. The rear subunit includes a first rear-subunit and a second rear-subunit. Each of the first rear-subunit and the second rear-subunit includes a negative lens and at least one positive lens. Lens materials are suitably set for the first rear-subunit and the rear second-subunit.

A zoom lens system, in which chromatic aberration, spherical aberration, and coma may be excellently corrected in a balanced manner so as to obtain excellent optical performance over an entire zoom range, includes, in order from an object side to an image side: a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; and a rear lens group including a lens unit having a positive refractive power, in which: at least one of the first lens unit and the second lens unit is moved for zooming so that an interval therebetween at a telephoto end is larger than an interval at a wide angle end; the first lens unit includes at least one negative lens; and an Abbe number (νd1n) and a partial dispersion ratio (θgF1n) of a material of the at least one negative lens are appropriately set.

A lens system comprising, in order from an object side: a first lens group G1; and a second lens group G2 having positive refractive power; the first lens group G1 including a sub-lens group GS11 having positive refractive power, and a sub-lens group GS12 having negative refractive power, the sub-lens group GS12 having negative refractive power including a meniscus lens having a convex surface facing the object side, given conditions being satisfied: an antireflection coating being formed on at least one optical surface in the first lens group G1 and the second lens group G2, and the antireflection coating including at least one layer formed by a wet-process, thereby providing a lens system having high optical performance with excellently correcting various aberrations and suppressing ghost images and flare, and an optical apparatus equipped therewith.

A zoom lens system, in which chromatic aberration, spherical aberration, and coma may be excellently corrected in a balanced manner so as to obtain excellent optical performance over an entire zoom range, includes, in order from an object side to an image side: a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; and a rear lens group including a lens unit having a positive refractive power, in which: at least one of the first lens unit and the second lens unit is moved for zooming so that an interval therebetween at a telephoto end is larger than an interval at a wide angle end; the first lens unit includes at least one negative lens; and an Abbe number (νd1n) and a partial dispersion ratio (θgF1n) of a material of the at least one negative lens are appropriately set.

A lens for projection substantially consists of a negative first lens with its concave surface facing a reduction side, a positive second lens with its concave surface facing the reduction side, a negative third lens with its concave surface facing a magnification side, a positive fourth lens with its convex surface facing the reduction side, a positive fifth lens and a positive sixth lens in this order from the magnification side. The reduction side is telecentric. The following conditional formulas (1) and (2) about refractive power P4 of a reduction-side surface of the second lens, refractive power P5 of a magnification-side surface of the third lens, and focal length f of an entire system are satisfied:−3.0≦1 / (P4×f)≦−0.4   (1); and−2.0≦1 / (P5×f)≦−0.2   (2).

A lens system comprising, in order from an object side: a first lens group G1; and a second lens group G2 having positive refractive power; the first lens group G1 including a sub-lens group GS11 having positive refractive power, and a sub-lens group GS12 having negative refractive power, the sub-lens group GS12 having negative refractive power including a meniscus lens having a convex surface facing the object side, given conditions being satisfied: an antireflection coating being formed on at least one optical surface in the first lens group G1 and the second lens group G2, and the antireflection coating including at least one layer formed by a wet-process, thereby providing a lens system having high optical performance with excellently correcting various aberrations and suppressing ghost images and flare, and an optical apparatus equipped therewith.

Providing a zoom lens system with a vibration reduction function excellently correcting aberrations with accomplishing compact, lightweight, and slim upon being accommodated, and to provide an optical apparatus using the zoom lens system. The system consists of, in order from an object, a first group having negative power, a second group having positive power. Upon zooming from a wide-angle end to a telephoto end, a distance between the first group and the second group decreases. The first group consists of, in order from the object, a first lens having negative power and a second lens having positive power. The second group consists of, in order from the object, a third lens having positive power, a fourth lens having negative power, and a fifth lens having positive power. An image blur is corrected by shifting the second group as a whole in a direction substantially perpendicular to the optical axis.

An immersion type microscope objective lens OL includes, in order from a cover plate C 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. The first lens group G1 includes at least one cemented lens. The second lens group G2 includes at least two achromatic lenses. The third lens group G3 includes, in order from the object side, an achromatic lens CL31 having a strong concave surface facing an image side, and an achromatic lens CL32 having a strong concave surface facing the object side.

An imaging lens consists of a first lens group, a second lens group, an aperture stop and a third lens group that has positive refractive power in this order from an object side. The first lens group consists of an L11 lens having positive refractive power, an L12 lens having negative refractive power, an L13 meniscus lens having negative refractive power with its concave surface facing an image side, an L14 lens having negative refractive power with its concave surface facing the object side and two or three lenses, each having positive refractive power, in this order from the object side. The second lens group consists of an L2p lens having positive refractive power and an L2n lens having negative refractive power.

A rear attachment lens changes a focal-length of an entire lens-system, in which the rear attachment lens has been attached to a main-lens, to a longer focal-length-side than a focal-length of the main-lens by being attached to an image-side of the main-lens. The rear attachment lens consists essentially of a first-lens-group and a second-lens-group in this order from an object-side. The first-lens-group consists essentially of a negative lens and a positive lens in this order from the object-side. The second-lens-group consists essentially of at least one negative lens and at least one positive lens, and a lens closest to an image-side in the second lens-group is a positive lens. When an Abbe number for d-line and a partial dispersion ratio between g-line and F-line of the negative lens in the first-lens-group are νd1 and θgF1, respectively, conditional expression (1): νd1>62 and conditional expression (2): 0.64<θgF1+0.001625 ×νd1<0.69 are satisfied.

A variable magnification optical system includes a positive first lens group, a negative second lens group, a stop, a positive third lens group and a positive fourth lens group, which are in this order from an object side. The first lens group, the stop and the third lens group are fixed, but the second lens group and the fourth lens group move in an optical axis direction during magnification change. The fourth lens group has a focusing function. The third lens group includes at least an aspherical surface, and consists of, in the following order from the object side, a positive lens and a cemented lens of a positive lens and a double-concave lens cemented together. The variable magnification optical system satisfies a predetermined formula.

A zoom lens consists of a first lens-group having positive refractive-power, a second lens-group having negative refractive-power, a third lens-group having positive refractive-power, a fourth lens-group having negative refractive-power, and a fifth lens-group having positive refractive-power in this order from an object-side. The third lens-group includes a cemented lens closest to an image-side consisting of a negative lens and a positive lens in this order from the object-side, and a cemented surface of which is convex toward the object-side. Further, distances between the lens-groups change, and the fifth lens-group is fixed, and at least the first lens-group and the fourth lens-group move in such a manner that the first lens-group and the fourth lens-group are located closer to the object-side at a telephoto-end than their positions at a wide-angle-end, respectively, when magnification is changed from the wide-angle-end to the telephoto-end. Further, the following conditional expression is satisfied:3.50<|D1| / |D4|<8.00  (1).

A zoom lens consists of a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having negative refractive power, and a fifth lens group having positive refractive power in this order from an object side. The third lens group includes a cemented lens closest to the object side and a cemented lens closest to an image side, and the fourth lens group consists of a negative lens and a positive lens in this order from the object side. Distances between the lens groups change, and the fifth lens group is fixed, and at least the first lens group and the fourth lens group move when magnification is changed from the wide angle end to the telephoto end.

A lens for projection substantially consists of a negative first lens with its concave surface facing a reduction side, a positive second lens with its concave surface facing the reduction side, a negative third lens with its concave surface facing a magnification side, a positive fourth lens with its convex surface facing the reduction side, a positive fifth lens and a positive sixth lens in this order from the magnification side. The reduction side is telecentric. The following conditional formulas (1) and (2) about refractive power P4 of a reduction-side surface of the second lens, refractive power P5 of a magnification-side surface of the third lens, and focal length f of an entire system are satisfied:−3.0≦1 / (P4×f)≦−0.4  (1); and−2.0≦1 / (P5×f)≦−0.2  (2).

An imaging lens consists of a first lens group, a second lens group, an aperture stop and a third lens group that has positive refractive power in this order from an object side. The first lens group consists of an L11 lens having positive refractive power, an L12 lens having negative refractive power, an L13 meniscus lens having negative refractive power with its concave surface facing an image side, an L14 lens having negative refractive power with its concave surface facing the object side and two or three lenses, each having positive refractive power, in this order from the object side. The second lens group consists of an L2p lens having positive refractive power and an L2n lens having negative refractive power.

An imaging lens includes negative first lens, negative second lens, third lens of a plano-convex shape having a convex surface directed toward an object side or of a positive meniscus shape having a convex surface directed toward the object side, and a fourth lens of a plano-convex shape having a convex surface directed toward an image side or of a positive meniscus shape having a convex surface directed toward the image side, which are arranged in this order from the object side. Further, the following conditional formula (6) is satisfied:0.75≦(R8−R9) / (R8+R9)≦1.0  (6), whereR8: a curvature radius of an object-side surface of the fourth lens, andR9: a curvature radius of an image-side surface of the fourth lens.

An imaging lens consists of negative first lens, negative second lens of a biconcave shape, third lens of a plano-convex shape having a convex surface directed toward an object side or of a positive meniscus shape having a convex surface directed toward the object side, and a fourth lens of a plano-convex shape having a convex surface directed toward an image side or of a positive meniscus shape having a convex surface directed toward the image side, which are arranged in this order from the object side. Further, the following conditional formula (11) is satisfied:3.1<R4 / f  (11),whereR4: a curvature radius of an image-side surface of the second lens, andf: a focal length of an entire system.

An imaging lens consists of a negative first lens, a negative second lens, a third lens of a plano-convex shape having a convex surface directed toward an object side or of a positive meniscus shape having a convex surface directed toward the object side, and a fourth lens of a plano-convex shape having a convex surface directed toward an image side or of a positive meniscus shape having a convex surface directed toward the image side, which are arranged in this order from the object side. Further, the following conditional formula (3) is satisfied: 1.0<|f2 / f|<2.6  (3), where f: a focal length of an entire system, and f2: a focal length of the second lens.

An imaging lens includes a negative first lens, a negative second lens, a third lens of a plano-convex shape having a convex surface directed toward an object side or of a positive meniscus shape having a convex surface directed toward the object side, and a fourth lens of a plano-convex shape having a convex surface directed toward an image side or of a positive meniscus shape having a convex surface directed toward the image side, which are arranged in this order from the object side. Further, the following conditional formula (4) is satisfied:1.0<D2 / f<2.5  (4),wheref: a focal length of an entire system, andD2: a distance on an optical axis between the first lens and the second lens.