Objective lens system for microscopes

Claim 2

An objective lens system for microscopes comprising a front lens group consisting of a first positive cemented doublet component, a second lens component having positive refractive power and a third lens component having positive refractive power, and a rear lens group consisting only of a negative three-element cemented lens component, and said lens system satisfying the following conditions: (1) 0.55<r 3 /r 1 <1.04 (2) 80<{(ν 2 -ν 1 )+(ν p -ν n )}<130 (3) -0.05<f 1 /f 2 <0 (4) 0.1<|(N-1)f/R|<0.4 wherein the reference symbols r 1 and r 3 represent radii of curvature on the object side surface and image side surface respectively of the first lens component, the reference symbol R designates radius of curvature on the image side surface of the positive single-element lens component arranged in said front lens group, the reference symbol N denotes refractive index of the positive single-element lens component arranged in said front lens group, the reference symbols ν 1 and ν 2 represent Abbe's numbers of both the elements respectively of said first lens component, the reference symbols ν p and ν n designate Abbe's numbers of the positive and negative elements respectively of the cemented doublet component arranged in addition to said first lens component in said front lens group, the reference symbols f 1 and f 2 denote focal lengths of said front lens group and said rear lens group respectively, and the reference symbol f represents focal length of the objective lens system as a whole.

Claim 3

An objective lens system for microscopes according to claim 1 satisfying additionally the following condition (5): (5) 0.4<f/d 8 <0.6 wherein the reference symbol d 8 represents airspace reserved between said third lens component and said fourth lens component.

Claim 4

An objective lens system for microscopes according to claim 1 wherein said second lens component is a positive single-element lens and said third lens component is a positive cemented doublet consisting of a negative lens element and a positive lens element.

Claim 5

An objective lens system for microscopes according to claim 3 having the following numerical data: ______________________________________ r.sub.1 = -0.9781 d.sub.1 = 0.3089 n.sub.1 = 1.61659 ν.sub.1 = 36.63 r.sub.2 = 1.2260 d.sub.2 = 0.6425 n.sub.2 = 1.43389 ν.sub.2 = 95.15 r.sub.3 = -0.8122 d.sub.3 = 0.0124 r.sub.4 = 5.4807 d.sub.4 = 0.4571 n.sub.3 = 1.49700 ν.sub.3 = 81.60 r.sub.5 = -1.4916 d.sub.5 = 0.0259 r.sub.6 = 3.8496 d.sub.6 = 0.1730 n.sub.4 = 1.56883 ν.sub.4 = 56.14 r.sub.7 = 1.4447 d.sub.7 = 0.6177 n.sub.5 = 1.43389 ν.sub.5 = 95.15 r.sub.8 = -2.1480 d.sub.8 = 2.0385 r.sub.9 = 2.9945 d.sub.9 = 0.2076 n.sub.6 = 1.50847 ν.sub.6 = 60.83 r.sub.10 = 1.1828 d.sub.10 = 0.6177 n.sub.7 = 1.43389 ν.sub.7 = 95.15 r.sub.11 = -1.0258 d.sub.11 = 0.2051 n.sub.8 = 1.64250 ν.sub.8 = 58.37 r.sub.12 = -11.4926 f = 1 NA = 0.65 β = -20X f.sub.1 = 1.11 f.sub.2 = -35.27 ______________________________________ wherein the reference symbols r 1 through r 12 represent radii of curvature on the surfaces of the respective lens elements, the reference symbols d 1 through d 11 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 8 denote refractive indices of the respective lens elements, the reference symbols ν 1 through ν 8 represent Abbe's numbers of the respective lens elements, the reference symbol f designates focal length of the objective lens system as a whole, the reference symbols f 1 and f 2 denote focal lengths of said front lens group and said rear lens group respectively, the reference symbol N.A. designates numerical aperture, and the reference symbol β represents magnification.

Claim 6

An objective lens system for microscopes according to claim 3 having the following numerical data: ______________________________________ r.sub.1 = -0.9200 d.sub.1 = 0.3116 n.sub.1 = 1.64769 ν.sub.1 = 33.80 r.sub.2 = 1.7248 d.sub.2 = 0.6484 n.sub.2 = 1.43389 ν.sub.2 = 95.15 r.sub.3 = -0.7913 d.sub.3 = 0.0125 r.sub.4 = -10.7611 d.sub.4 = 0.4612 n.sub.3 = 1.49700 ν.sub.3 = 81.60 r.sub.5 = -1.3783 d.sub.5 = 0.0262 r.sub.6 = 3.3946 d.sub.6 = 1.1745 n.sub.4 = 1.64769 ν.sub.4 = 33.80 r.sub.7 = 2.5315 d.sub.7 = 0.6232 n.sub.5 = 1.43389 ν.sub.5 = 95.15 r.sub.8 = -2.1188 d.sub.8 = 2.0566 r.sub.9 = 2.3414 d.sub.9 = 0.2094 n.sub.6 = 1.64250 ν.sub.6 = 58.37 r.sub.10 = 1.0474 d.sub.10 = 0.6232 n.sub.7 = 1.43389 ν.sub.7 = 95.15 r.sub.11 = -0.9294 d.sub.11 = 0.2069 n.sub.8 = 1.50847 ν.sub.8 = 60.83 r.sub.12 = 10.1701 f = 1 NA = 0.65 β = -20X f.sub.1 = 1.14 f.sub.2 = -25.79 ______________________________________ wherein the reference symbols r 1 through r 12 represent radii of curvature on the surfaces of the respective lens elements, the reference symbols d 1 through d 11 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 8 denote refractive indices of the respective lens elements, the reference symbols ν 1 through ν 8 represent Abbe's numbers of the respective lens elements, the reference symbol f designates focal length of the objective lens system as a whole, the reference symbols f 1 and f 2 denote focal lengths of said front lens group and said rear lens group respectively, the reference symbol N.A. designates numerical aperture, and the reference symbol β represents magnification.

Claim 7

An objective lens system for microscopes according to claim 3 having the following numerical data: ______________________________________ r.sub.1 = -1.0680 d.sub.1 = 0.3074 n.sub.1 = 1.64769 ν.sub.1 = 33.80 r.sub.2 = 1.5381 d.sub.2 = 0.6393 n.sub.2 = 1.43389 ν.sub.2 = 95.15 r.sub.3 = -0.7434 d.sub.3 = 0.0369 r.sub.4 = 9.7852 d.sub.4 = 0.4303 n.sub.3 = 1.49700 ν.sub.3 = 81.60 r.sub.5 = -1.3552 d.sub.5 = 0.0258 r.sub.6 = 4.7414 d.sub.6 = 0.1721 n.sub.4 = 1.64769 ν.sub.4 = 33.80 r.sub.7 = 2.7423 d.sub.7 = 0.6147 n.sub.5 = 1.43389 ν.sub.5 = 95.15 r.sub.8 = -2.7416 d.sub.8 = 2.0285 r.sub.9 = 2.2594 d.sub.9 = 0.1820 n.sub.6 = 1.64250 ν.sub.6 = 58.37 r.sub.10 = 1.0714 d.sub.10 = 0.6393 n.sub.7 = 1.43389 ν.sub.7 = 95.15 r.sub.11 = -0.9407 d.sub.11 = 0.2041 n.sub.8 = 1.50378 ν.sub.8 = 66.81 r.sub.12 = 15.0200 f = 1 NA = 0.65 β = -20X f.sub.1 = 1.09 f.sub.2 = -255.69 ______________________________________ wherein the reference symbols r 1 through r 12 represent radii of curvature on the surfaces of the respective lens elements, the reference symbols d 1 through d 11 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 8 denote refractive indices of the respective lens elements, the reference symbols ν 1 through ν 8 represent Abbe's numbers of the respective lens elements, the reference symbol f designates focal length of the objective lens system as a whole, the reference symbols f 1 and f 2 denote focal lengths of said front lens group and said rear lens group respectively, the reference symbol N.A. designates numerical aperture, and the reference symbol β represents magnification.

Claim 8

An objective lens system for microscopes according to claim 1 wherein said second lens component is a positive cemented doublet consisting of a negative lens element and a positive lens element, and said third lens component is a positive single-element lens.

Claim 9

An objective lens system for microscopes according to claim 7 having the following numerical data: ______________________________________ r.sub.1 = -0.9636 d.sub.1 = 0.3121 n.sub.1 = 1.64769 ν.sub.1 = 33.80 r.sub.2 = 1.8749 d.sub.2 = 0.6493 n.sub.2 = 1.43389 ν.sub.2 = 95.15 r.sub.3 = -0.7219 d.sub.3 = 0.0125 r.sub.4 = 3.7964 d.sub.4 = 0.1748 n.sub.3 = 1.64769 ν.sub.3 = 33.80 r.sub.5 = 2.5147 d.sub.5 = 0.6243 n.sub.4 = 1.43389 ν.sub.4 = 95.15 r.sub.6 = -1.7094 d.sub.6 = 0.0262 r.sub.7 = 6.3585 d.sub.7 = 0.4620 n.sub.5 = 1.49700 ν.sub.5 = 81.60 r.sub.8 = -3.0137 d.sub.8 = 2.0602 r.sub.9 = 1.9644 d.sub.9 = 0.2098 n.sub.6 = 1.64250 ν.sub.6 = 58.37 r.sub.10 = 0.9655 d.sub.10 = 0.6243 n.sub.7 = 1.43389 ν.sub.7 = 95.15 r.sub.11 = -0.9838 d.sub.11 = 0.2073 n.sub.8 = 1.49782 ν.sub.8 = 66.83 r.sub.12 = 4.8303 f = 1 NA = 0.65 β = -20X f.sub.1 = 1.16 f.sub.2 = -31.91 ______________________________________ wherein the reference symbols r 1 through r 12 represent radii of curvature on the surfaces of the respective lens elements, the reference symbols d 1 through d 11 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 8 denote refractive indices of the respective lens elements, the reference symbols ν 1 through ν 8 represent Abbe's numbers of the respective lens elements, the reference symbol f designates focal length of the objective lens system as a whole, the reference symbols f 1 and f 2 denote focal lengths of said front lens group and said rear lens group respectively, the reference symbol N.A. designates numerical aperture, and the reference symbol β represents magnification.