Lens system for micro film

Claim 2

A lens system for micro film comprising a first positive lens component, a second meniscus lens component, a third negative lens component, a fourth cemented doublet component having a concave surface on the object side, a fifth positive cemented doublet component, a sixth positive lens component and a seventh cemented doublet component having a concave surface on the image side and consisting of a negative lens element and a positive lens element, and said lens system satisfying the following conditions:

Claim 3

(1) 1.49f<r 4 <1.51f

Claim 4

(1) 1.49f<r 4 <1.51f

Claim 5

(2) -0.02f<1/r 5 <0.08/f

Claim 6

(2) -0.02f<1/r 5 <0.08/f

Claim 7

(3) 0.46f<r 6 <0.48f

Claim 8

(3) 0.46f<r 6 <0.48f

Claim 9

(4) -0.47f<r 7 <-0.45f wherein the reference symbols r 4 , r 5 and r 6 represent radii of curvature of the image side surface of the second lens component, the object side surface and image side surface of the third lens component and object side surface of the fourth lens component respectively and the reference symbol f designates focal length of the entire lens system as a whole.

Claim 10

(4) -0.47f<r 7 <-0.45f wherein the reference symbols r 4 , r 5 and r 6 represent radii of curvature of the image side surface of the second lens component, the object side surface and image side surface of the third lens component and object side surface of the fourth lens component respectively and the reference symbol f designates focal length of the entire lens system as a whole.

Claim 11

A lens system for micro film according to claim 1 having the following numerical data: ______________________________________ f = 1.0 , β = 1/10 , N.A = 0.3 ______________________________________ r.sub.1 = 1.6944 d.sub.1 = 0.2531 n.sub.1 = 1.65306 ν.sub.1 = 60.2 r.sub.2 = -7.9950 d.sub.2 = 0.0027 r.sub.3 = 0.9213 d.sub.3 = 0.2268 n.sub.2 = 1.75176 ν.sub.2 = 51.3 r.sub.4 = 1.5006 d.sub.4 = 0.0757 r.sub.5 = 12.8265 d.sub.5 = 0.1209 n.sub.3 = 1.52619 ν.sub.3 = 64.0 r.sub.6 = 0.4699 d.sub.6 = 0.2956 r.sub.7 = -0.4592 d.sub.7 = 0.0947 n.sub.4 = 1.80878 ν.sub.4 = 47.4 r.sub.8 = 4.9587 d.sub.8 = 0.3022 n.sub.5 = 1.65306 ν.sub.5 = 60.2 r.sub.9 = -0.7641 d.sub.9 = 0.0039 r.sub.10 = 2.6951 d.sub.10 = 0.0757 n.sub.6 = 1.69992 ν.sub.6 = 32.1 r.sub.11 = 0.9254 d.sub.11 = 0.3022 n.sub.7 = 1.65306 ν.sub.7 = 60.2 r.sub.12 = -1.2079 d.sub.12 = 0.0037 r.sub.13 = 1.8887 d.sub.13 = 0.1588 n.sub.8 = 1.65306 ν.sub.8 = 60.2 r.sub.14 = -299.8532 d.sub.14 = 0.0259 r.sub.15 = 0.9668 d.sub.15 = 0.1890 n.sub.9 = 1.75376 ν.sub.9 = 29.2 r.sub.16 = 0.5543 d.sub.16 = 0.4320 n.sub.10 = 1.65306 ν.sub.10 = 60.2 r.sub.17 = 1.3012 ______________________________________ wherein the reference symbols r 1 through r 17 represent radii of curvature on the surfaces of the respective lens elements, the reference symbols d 1 through d 16 designate thicknesses of the respective lens elements and the airspaces therebetween, the reference symbols n 1 through n 10 denote refractive indices of the respective lens elements and the reference symbols ν 1 through ν 10 represent Abbe's numbers of the respective lens elements.

Claim 12

A lens system for micro film according to claim 1 wherein a positive lens element is added on the object side of said first lens component.

Claim 13

A lens system for micro film according to claim 3 having the following numerical data: ______________________________________ f = 1.0 , β = 1/10 , N.A = 0.3 ______________________________________ r.sub.0 = -33.8952 d.sub.0 = 0.2598 n.sub.0 = 1.49593 ν.sub.0 = 69.8 r.sub.0' = -5.9913 d.sub.0' = 0.9724 r.sub.1 = 1.7523 d.sub.1 = 0.2485 n.sub.1 = 1.65306 ν.sub.1 = 60.2 r.sub.2 = -12.1051 d.sub.2 = 0.0027 r.sub.3 = 0.9230 d.sub.3 = 0.2224 n.sub.2 = 1.75176 ν.sub.2 = 51.3 r.sub.4 = 1.5059 d.sub.4 = 0.0741 r.sub.5 = -89.4819 d.sub.5 = 0.1188 n.sub.3 = 1.52619 ν.sub.3 = 64.0 r.sub.6 = 0.4651 d.sub.6 = 0.2901 r.sub.7 = -0.4534 d.sub.7 = 0.0927 n.sub.4 = 1.80878 ν.sub.4 = 47.4 r.sub.8 = 5.2371 d.sub.8 = 0.2969 n.sub.5 = 1.65306 ν.sub.5 = 60.2 r.sub.9 = -0.7660 d.sub.9 = 0.0038 r.sub.10 = 3.0174 d.sub.10 = 0.0741 n.sub.6 = 1.69992 ν.sub.6 = 32.1 r.sub.11 = 0.9575 d.sub.11 = 0.2969 n.sub.7 = 1.65306 ν.sub.7 = 60.2 r.sub.12 = -1.1374 d.sub.12 = 0.0038 r.sub.13 = 1.7454 d.sub.13 = 0.1558 n.sub.8 = 1.65306 ν.sub.8 = 60.2 r.sub.14 = ∞ d.sub.14 = 0.0253 r.sub.15 = 0.8624 d.sub.15 = 0.1853 n.sub.9 = 1.75376 ν.sub.9 = 29.2 r.sub.16 = 0.5138 d.sub.16 = 0.4240 n.sub.10 = 1.65306 ν.sub.10 = 60.2 r.sub.17 = 1.1629 ______________________________________ wherein the reference symbols r 1 through r 17 represent radii of curvature on the surfaces of the respective lens elements, the reference symbols d 1 through d 16 designate thicknesses of the respective lens elements and the airspaces therebetween, the reference symbols n 1 through n 10 denote refractive indices of the respective lens elements and the reference symbols ν 1 through ν 10 represent Abbe's numbers of the respective lene elements.