Achromatic microscope objective

Claim 2

An achromatic microscope objective with a magnification within the range of 35× and 45× and a numerical aperture greater than 0.60, the complete objective having only four lens elements forming three lens components, the first component, numbering the components consecutively from front to rear, being a single positive element, the second component also being a single positive element, and the third component being a cemented doublet consisting of a front negative element and a rear biconvex positive element, the refractive index n d and the Abbe number v d of each element being within the range indicated in the following table: ______________________________________ Element 1 [1.70] 1.63 > n.sub.d > 1.55 [68] 64 > v.sub.d > 56 [45] Element 2 1.70 > n.sub.d > 1.57 [1.55] [68] 62 > v.sub.d > 55 [45] Element 3 [1.97] 1.93 > n.sub.d > 1.75 [1.65] [40] 29 > v.sub.d > 21 [20] Element 4 [1.57] 1.53 > n.sub.d > 1.47 [1.46] 85 > v.sub.d > 51 [50] ______________________________________

Claim 3

The invention defined in claim 1, wherein the air spacing between the second component and the third component is not more than 0.8 times the equivalent focal length of the objective.

Claim 4

An achromatic microscope objective as defined in claim 1, wherein the characteristics of the lens elements and their spatial relationship to each other are substantially in the proportions indicated by the data in the following table, the radii of the respective surfaces being designated by r with a numerical subscript indentifying the particular surface numbered consecutively from front to rear, the thicknesses and spacings being designated by d with a numerical subscript identifying the particular thickness or space numbered in a single series from front to rear, linear dimensions being in millimeters, the respective indices of refraction of the elements being given in the column headed n d , and the Abbe numbers being given in the column headed v d : __________________________________________________________________________ Radius Thickness Spacing Refraction Abbe-number Lens r d d index n.sub.d ν.sub.d __________________________________________________________________________ d.sub.1 = 0.130 I r.sub.1 = -1.089 d.sub.2 = 0.624 1.60738 56.65 r.sub.2 = -0.640 d.sub.3 = 0.098 II r.sub.3 = 7.938 d.sub.4 = 0.520 1.62041 60.33 r.sub.4 = -1.371 d.sub.5 = 0.704 III r.sub.5 = 4.902 d.sub.6 = 0.217 1.78470 26.08 r.sub.6 = 1.105 d.sub.7 = 0.761 1.51112 60.41 r.sub.7 = -2.143 __________________________________________________________________________

Claim 5

An achromatic microscope objective as defined in claim 1, wherein the characteristics of the lens elements and their spatial relationship to each other are substantially in the proportions indicated by the data in the following table, the radii of the respective surfaces being designated by r with a numerical subscript indentifying the particular surface numbered consecutively from front to rear, the thicknesses and spacings being designated by d with a numerical subscript identifying the particular thickness or space numbered in a single series from front to rear, linear dimensions being in millimeters, the respective indices of refraction of the elements being given in the column headed n d , and the Abbe numbers being given in the column headed v d : __________________________________________________________________________ Radius Thickness Spacing Refraction Abbe-number Lens r d d index n.sub.d ν.sub.d __________________________________________________________________________ d.sub.1 = 0.140 I r.sub.1 = -1.058 d.sub.2 = 0.623 1.60738 56.65 r.sub.2 = -0.639 d.sub.3 = 0.098 II r.sub.3 = 7.935 d.sub.4 = 0.519 1.62041 60.33 r.sub.4 = -1.371 d.sub.5 = 0.690 III r.sub.5 = 4.904 d.sub.6 = 0.192 1.78470 26.08 r.sub.6 = 1.092 d.sub.7 = 0.760 1.51112 60.41 r.sub.7 = -2.142 __________________________________________________________________________

Claim 6

An achromatic microscope objective as defined in claim 1, wherein the characteristics of the lens elements and their spatial relationship to each other are substantially in the proportions indicated by the data in the following table, the radii of the respective surfaces being designated by r with a numerical subscript indentifying the particular surface numbered consecutively from front to rear, the thicknesses and spacings being designated by d with a numerical subscript identifying the particular thickness or space numbered in a single series from front to rear, linear dimensions being in millimeters, the respective indices of refraction of the elements being given in the column headed n d , and the Abbe numbers being given in the column headed v d : __________________________________________________________________________ Radius Thickness Spacing Refraction Abbe-number Lens r d d index n.sub.d ν.sub.d __________________________________________________________________________ d.sub.1 = 0.134 I r.sub.1 = -1.149 d.sub.2 = 0.622 1.60738 56.65 r.sub.2 = -0.646 d.sub.3 = 0.097 II r.sub.3 = 8.017 d.sub.4 = 0.524 1.62041 60.33 r.sub.4 = -1.385 d.sub.5 = 0.700 III r.sub.5 = 4.951 d.sub.6 = 0.244 1.78470 26.08 r.sub.6 = 1.116 d.sub.7 = 0.768 1.51112 60.41 r.sub.7 = -2.164 __________________________________________________________________________

Claim 7

An achromatic microscope objective as defined in claim 1, wherein the characteristics of the lens elements and their spatial relationship to each other are substantially in the proportions indicated by the data in the following table, the radii of the respective surfaces being designated by r with a numerical subscript indentifying the particular surface numbered consecutively from front to rear, the thicknesses and spacings being designated by d with a numerical subscript identifying the particular thickness or space numbered in a single series from front to rear, linear dimensions being in millimeters, the respective indices of refraction of the elements being given in the column headed n d , and the Abbe numbers being given in the column headed v d : __________________________________________________________________________ Radius Thickness Spacing Refraction Abbe-number Lens r d d index n.sub.d ν.sub.d __________________________________________________________________________ d.sub.1 = 0.155 I r.sub.1 = -0.798 d.sub.2 = 0.493 1.62014 63.52 r.sub.2 = -0.546 d.sub.3 = 0.044 II r.sub.3 = 68.959 d.sub.4 = 0.653 1.58913 61.27 r.sub.4 = -1.106 d.sub.5 = 0.737 III r.sub.5 = 5.377 d.sub.6 = 0.318 1.75520 27.58 r.sub.6 = 1.152 d.sub.7 = 0.778 1.49782 66.95 r.sub.7 = -1.945 __________________________________________________________________________

Claim 8

An achromatic microscope objective as defined in claim 1, wherein the characteristics of the lens elements and their spatial relationship to each other are substantially in the proportions indicated by the data in the following table, the radii of the respective surfaces being designated by r with a numerical subscript indentifying the particular surface numbered consecutively from front to rear, the thicknesses and spacings being designated by d with a numerical subscript identifying the particular thickness or space numbered in a single series from front to rear, linear dimensions being in millimeters, the respective indices of refraction of the elements being given in the column headed n d , and the Abbe numbers being given in the column headed v d : __________________________________________________________________________ Radius Thickness Spacing Refraction Abbe-number Lens r d d index n.sub.d ν.sub.d __________________________________________________________________________ d.sub.1 = 0.164 I r.sub.1 = -1.057 d.sub.2 = 0.613 1.55232 63.46 r.sub.2 = -0.660 d.sub.3 = 0.027 II r.sub.3 = -51.411 d.sub.4 = 0.361 1.69680 55.41 r.sub.4 = -1.188 d.sub.5 = 0.687 III r.sub.5 = 3.862 d.sub.6 = 0.435 1.91761 21.51 r.sub.6 = 1.175 d.sub.7 = 0.868 1.51118 51.01 r.sub.7 = -1.804 __________________________________________________________________________

Claim 9

An achromatic microscope objective as defined in claim 1, wherein the characteristics of the lens elements and their spatial relationship to each other are substantially in the proportions indicated by the data in the following table, the radii of the respective surfaces being designated by r with a numerical subscript indentifying the particular surface numbered consecutively from front to rear, the thicknesses and spacings being designated by d with a numerical subscript identifying the particular thickness of space numbered in a single series from front to rear, linear dimensions being in millimeters, the respective indices of refraction of the elements being given in the column headed n d , and the Abbe numbers being given in the column headed v d : __________________________________________________________________________ Radius Thickness Spacing Refraction Abbe-number Lens r d d index n.sub.d ν.sub.d __________________________________________________________________________ d.sub.1 = 0.155 I r.sub.1 = -1.373 d.sub.2 = 0.651 1.55232 63.46 r.sub.2 = -0.669 d.sub.3 = 0.035 II r.sub.3 = 17.657 d.sub.4 = 0.536 1.69680 55.41 r.sub.4 = -1.380 d.sub.5 = 0.631 III r.sub.5 = 3.765 d.sub.6 = 0.361 1.79504 28.39 r.sub.6 = 1.097 d.sub.7 = 0.853 1.48656 84.47 r.sub.7 = -2.125 __________________________________________________________________________