Photo eyepiece for endoscopes

Claim 2

A photo eyepiece for endoscopes comprising a positive cemented meniscus lens component having a concave surface on the object side, a positive lens component, a positive meniscus lens component having a convex surface on the object side and a negative cemented meniscus lens component having a convex surface on the object side, and said photo eyepiece system satisfying the following conditions: (1) ν 1p -ν 1n >ν 2p -ν 2n (2) 0.43f<R<0.47f wherein the reference symbols ν 1p and ν 1n represent Abbe's numbers of the positive and negative elements respectively of said positive cemented meniscus lens component, the reference symbols ν 2p and ν 2n designate Abbe's numbers of the positive and negative elements respectively of said negative cemented meniscus lens component, the reference symbol R denotes radius of curvature on the surface located on the extreme image side and the reference symbol f represents focal length of the photo eyepiece system as a whole.

Claim 3

A photo eyepiece for endoscopes according to claim 1 satisfying the following conditions (3) through (6): (3) 1.2f<R 1 <1.8f (4) 0.26<N 1n -N 1p >0.14 (5) N 2p >N 2n (6) 2.0f<R 2 <2.8f wherein the reference symbol R 1 denotes radius of curvature on the cemented surface of said positive cemented meniscus lens component, the reference symbol R 2 designates radius of curvature of the cemented surface of said negative cemented meniscus lens component, the reference symbols N 1p and N 1n denote refractive indices of the positive and negative elements respectively of said positive cemented meniscus lens component, and the reference symbols N 2p and N 2n represent refractive indices of the positive and negative elements respectively of said negative cemented meniscus lens component.

Claim 4

A photo eyepiece for endoscopes according to claim 2 having the following numerical data: ______________________________________ [f = 1.0] r.sub.1 = -1.0522 d.sub.1 = 0.108 n.sub.1 = 1.78472 ν.sub.1 = 25.71 r.sub.2 = [-] 1.7816 d.sub.2 = 0.434 n.sub.2 = 1.53113 ν.sub.2 = 62.44 r.sub.3 = -0.8659 d.sub.3 = 0.024 r.sub.4 = ∞ d.sub.4 = 0.217 n.sub.3 = 1.71300 ν.sub.3 = 53.89 r.sub.5 = -2.2460 d.sub.5 = 0.024 r.sub.6 = [-] 1.1113 d.sub.6 = 0.287 n.sub.4 = 1.71300 ν.sub.4 = 53.89 r.sub.7 = [-] 3.9609 d.sub.7 = 0.024 r.sub.8 = [-] 0.8587 d.sub.8 = 0.275 n.sub.5 = 1.71300 ν.sub.5 = 53.89 r.sub.9 = [-] 2.7982 d.sub.9 = 0.119 n.sub.6 = 1.59270 ν.sub.6 = 35.29 r.sub.10 = [-] 0.4687 f = 1.0 N.A. = 0.225 2ω = 6° ______________________________________ [Photographing] Photographing magnification: 7.5×- wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces therebetween, the reference symbols n 1 through n 6 denote refractive indices of the respective lens elements and the reference symbols ν 1 through ν 6 represent Abbe's numbers of the respective lens elements.

Claim 5

A photo eyepiece for endoscopes according to claim 2 having the following numerical data: ______________________________________ r.sub.1 = -4.7024 d.sub.1 = 0.341 n.sub.1 = 1.78472 ν.sub.1 = 25.71 r.sub.2 = [-] 1.2123 d.sub.2 = 0.302 n.sub.2 = 1.64000 ν.sub.2 = 60.09 r.sub.3 = -1.4684 d.sub.3 = 0.016 r.sub.4 = [-] 2.8125 d.sub.4 = 0.146 n.sub.3 = 1.71300 ν.sub.3 = 53.89 r.sub.5 = -5.3611 d.sub.5 = 0.016 r.sub.6 = [-] 0.8105 d.sub.6 = 0.188 n.sub.4 = 1.71300 ν.sub.4 = 53.89 r.sub.7 = [-] 1.5196 d.sub.7 = 0.016 r.sub.8 = [-] 0.8504 d.sub.8 = 0.174 n.sub.5 = 1.72600 ν.sub.5 = 53.56 r.sub.9 = [-] 2.0343 d.sub.9 = 0.080 n.sub.6 = 1.58267 ν.sub.6 = 46.33 r.sub.10 = [-] 0.4323 f = 1.0 N.A. = 0.225 2ω = 5.6° ______________________________________ Photographing magnification: 5× wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces therebetween, the reference symbols n 1 through n 6 denote refractive indices of the respective lens elements and the reference symbols ν 1 through ν 6 represent Abbe's numbers of the respective lens elements.