Abstract In a wide range of photographing from long shot to close-up, high resolving power and high contrast can be obtained in a wide angle lens system. The wide angle lens system comprises, successively from the object side, a negative meniscus first lens (L1), a junction lens composed of a positive second lens (L2) with a convex surface facing the object and a negative third lens (L3) with a concave surface facing the image, a junction lens composed of a biconvex fourth lens (L4) and a biconcave fifth lens (L5), a positive sixth lens (L6) with a convex surface facing the image, and a negative meniscus seventh lens (L7) with a convex lens facing the image. Also, it satisfies the following conditions (1) to (4): (1) -1.95<F 1 /f<-1.05 (2) 1.05<f 23 /f<3.60 (3) 1.10<f 45 /f<2.16 (4) 1.53<(r 11 +r 10 )/(r 11 -r 10 )<4.95
Inventors
👤 Nobuaki Toyama
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-11-08 02:19
CPC Classifications
G; G02; G02B; G02B13/00; G02B13/04
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
204 words
A wide angle lens system comprising successively from an object side: a negative meniscus first lens with a convex surface facing the object, a first junction lens composed of a positive second lens with a convex surface facing the object and a negative third lens with a concave surface facing an image, a second junction lens composed of a biconvex fourth lens and a biconcave fifth lens, a positive sixth lens with a convex surface facing the image, and a negative meniscus seventh lens with a convex lens facing the image, said lens system satisfying the following conditions (1) to (4): (1) -1.95<f 1 /f<-1.05 (2) 1.05<f 23 /f<3.60 (3) 1.10<f 45 /f<2.16 (4) 1.53<(r 11 +r 10 )/(r 11 -r 10 )<4.95 wherein f is combined focal length of this wide angle lens system as a whole, f 1 is focal length of the first lens, f 23 is combined focal length of the second and third lenses, f 45 is combined focal length of the fourth and fifth lenses, r 10 is radius of curvature of the surface of the sixth lens facing the image, and r 11 is radius of curvature of the surface of the seventh lens facing the object.
Claim 2
Dependent Claim
204 words
A wide angle lens system comprising successively from an object side: a negative meniscus first lens with a convex surface facing the object, a first junction lens composed of a positive second lens with a convex surface facing the object and a negative third lens with a concave surface facing an image, a second junction lens composed of a biconvex fourth lens and a biconcave fifth lens, a positive sixth lens with a convex surface facing the image, and a negative meniscus seventh lens with a convex lens facing the image, said lens system satisfying the following conditions (1) to (4): (1) -1.95<f 1 /f<-1.05 (2) 1.05<f 23 /f<3.60 (3) 1.10<f 45 /f<2.16 (4) 1.53<(r 11 +r 10 )/(r 11 -r 10 )<4.95 wherein f is combined focal length of this wide angle lens system as a whole, f 1 is focal length of the first lens, f 23 is combined focal length of the second and third lenses, f 45 is combined focal length of the fourth and fifth lenses, r 10 is radius of curvature of the surface of the sixth lens facing the image, and r 11 is radius of curvature of the surface of the seventh lens facing the object.
Claim 3
Dependent Claim
21 words
A wide angle lens system according to claim 1, further comprising a stop disposed between said first and second junction lenses.