Objective lens system for microscopes

Claim 2

An objective lens system for microscopes comprising a first cemented doublet component comprising a plano-convex lens element and a meniscus lens element having a strongly concave surface on the object side, a second meniscus lens component, a third cemented component comprising a positive lens element, a negative lens element and a positive lens element, a fourth cemented component comprising a negative meniscus lens elements, a biconvex lens element and a negative lens element, and a fifth cemented doublet component and a sixth cemented doublet component respectively having strongly concave surfaces opposite to each other, said lens system being so designed as to satisfy the following conditions (1) through (6): -0.1<f/f.sub.2 <0.05 (1) -0.1<f/f.sub.B <-0.07 (2) 1.75<n.sub.2 ( 3) 29<ν.sub.5 <45 (4) 60<ν.sub.6,ν.sub.8 ( 5) d.sub.16 <1.2f (6) wherein the reference symbol f represents focal length of said objective lens system as a whole, the reference symbol f 2 designates focal length of the image side lens element of said first lens component, the reference symbol f B denotes composite focal length of said fifth and sixth lens components as a whole, the reference symbol n 2 represents refractive index of the image side lens element of said first lens component, the reference symbols ν 5 and ν 6 designate Abbe's numbers of the middle negative lens element and the image side lens element respectively of said third lens component, the rererence symbol ν 8 denotes Abbe's number of the middle positive lens element of said fourth lens component and the reference symbol d 16 represents airspace reserved between said fifth and sixth lens components.

Claim 3

An objective lens system for microscopes according to claim 1 having the following numerical data: ______________________________________ r.sub.1 = ∞ d.sub.1 = 0.211 n.sub.1 = 1.51633 ν.sub.1 = 64.2 r.sub.2 = -0.625 d.sub.2 = 1.334 n.sub.2 = 1.883 ν.sub.2 = 40.8 r.sub.3 = -1.222 d.sub.3 = 0.029 r.sub.4 = -4.049 d.sub.4 = 1.073 n.sub.3 = 1.617 ν.sub.3 = 62.8 r.sub.5 = -2.210 d.sub.5 = 0.036 r.sub.6 = 8.517 d.sub.6 = 2.146 n.sub.4 = 1.6583 ν.sub.4 = 57.3 r.sub.7 = -2.834 d.sub.7 = 0.540 n.sub.5 = 1.65412 ν.sub.5 = 39.7 r.sub.8 = 3.772 d.sub.8 = 3.296 n.sub.6 = 1.43389 ν.sub.6 = 95.2 r.sub.9 = -3.777 d.sub.9 = 0.043 r.sub.10 = 5.511 d.sub.10 = 0.501 n.sub.7 = 1.6134 ν.sub.7 = 43.8 r.sub.11 = 2.650 d.sub.11 = 2.504 n.sub.8 = 1.43389 ν.sub.8 = 95.2 r.sub.12 = -2.655 d.sub.12 = 0.422 n.sub.9 = 1.52682 ν.sub.9 = 51.1 r.sub.13 = 3690.551 d.sub.13 = 0.036 r.sub.14 = 2.302 d.sub.14 = 1.538 n.sub.10 = 1.597 ν.sub.10 = 81.6 r.sub.15 = -4.982 d.sub.15 = 1.431 n.sub.11 = 1.52682 ν.sub.11 = 51.1 r.sub.16 = 1.141 d.sub.16 = 0.787 r.sub.17 = -1.265 d.sub.17 = 0.715 n.sub.12 = 1.81554 ν.sub.12 = 44.5 r.sub.18 = 3.806 d.sub.18 = 1.259 n.sub.13 = 1.7495 ν.sub.13 = 35.3 r.sub.19 = -2.162 f = 1, β = -60, NA = 1.4 1/f.sub.2 = 0.0341, 1/f.sub.B = -0.0761, WD = 0.0465 ______________________________________ wherein the reference symbols r 1 through r 19 represent radii of curvature on the surfaces of the respective lens elements, the reference symbols d 1 through d 18 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 13 denote refractive indices of the respective lens elements, the reference symbols ν 1 through ν 13 represent Abbe's numbers of the respective lens elements, the reference symbol β designates magnification level of said objective lens system as a whole and the reference symbol WD denotes working distance of said objective lens system as a whole.

Claim 4

An objective lens system for microscopes according to claim 1 having the following numerical data: ______________________________________ r.sub.1 = ∞ d.sub.1 = 0.248 n.sub.1 = 1.51633 ν.sub.1 = 64.2 r.sub.2 = -0.593 d.sub.2 = 1.369 n.sub.2 = 1.883 ν.sub.2 = 40.8 r.sub.3 = -1.302 d.sub.3 = 0.031 r.sub.4 = -3.358 d.sub.4 = 1.150 n.sub.3 = 1.617 ν.sub.3 = 62.8 r.sub.5 = -2.215 d.sub.5 = 0.037 r.sub.6 = 6.734 d.sub.6 = 2.416 n.sub.4 = 1.651 ν.sub.4 = 56.2 r.sub.7 = -3.288 d.sub.7 = 0.573 n.sub.5 = 1.6445 ν.sub.5 = 40.8 r.sub.8 = 3.736 d.sub.8 = 2.617 n.sub.6 = 1.43389 ν.sub.6 = 95.2 r.sub.9 = -4.388 d.sub.9 = 0.044 r.sub. 10 = 4.798 d.sub.10 = 0.475 n.sub.7 = 1.71852 ν.sub.7 = 33.5 r.sub.11 = 2.662 d.sub.11 = 2.445 n.sub.8 = 1.43389 ν.sub.8 = 95.2 r.sub.12 = -3.571 d.sub.12 = 0.438 n.sub.9 = 1.5213 ν.sub.9 = 52.6 r.sub.13 = 101.671 d.sub.13 = 0.044 r.sub.14 = 2.436 d.sub.14 = 1.606 n.sub.10 = 1.497 ν.sub.10 = 81.6 r.sub.15 = -5.282 d.sub.15 = 1.412 n.sub.11 = 1.5213 ν.sub.11 = 52.6 r.sub.16 = 1.249 d.sub.16 = 0.912 r.sub.17 = -1.370 d.sub.17 = 0.376 n.sub.12 = 1.6968 ν.sub.12 = 56.5 r.sub.18 = 3.782 d.sub.18 = 1.518 n.sub.13 = 1.5927 ν.sub.13 = 35.3 r.sub.19 = -2.100 f = 1, β = -60, NA = 1.4 1/f.sub.2 = -0.0765, 1/f.sub.B = -0.0835, WD = 0.043 ______________________________________ wherein the reference symbols r 1 through r 19 represent radii of curvature on the surfaces of the respective lens elements, the reference symbols d 1 through d 18 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 13 denote refractive indices of the respective lens elements, the reference symbols ν 1 through ν 13 represent Abbe's numbers of the respective lens elements, the reference symbol β designates magnification level of said objective lens system as a whole and the reference symbol WD denotes working distance of said objective lens system as a whole.