Apochromatically corrected microscope objective
View Patent ↗A microscope objective with high aperture, large object field and apochromatic correction in the wavelength range from ultraviolet to infrared. The microscope objective includes, starting from the object level: a first group of lenses with overall positive refraction power, including a cemented group with positive-negative refraction power effect, made out of one of two lenses, and of a further lens with positive refraction power, a second group of lenses with positive refraction power, including three cemented lenses, a third group of lenses with negative refraction power, including three cemented lenses, in which the side that faces the image plane is convex, a fourth group of lenses, consisting of a lens with positive refraction power and a cemented group of two lenses with positive-negative refraction power, and a fifth group of lenses, including two lenses in a cemented group with negative-positive refraction power.
1. An apochromatically corrected microscope objective, including, from an object end:
a first group of lenses (G 1 ) having overall positive refractive power, comprising a cemented group having two lenses (L 1 , L 2 ), including a first lens having positive refractive power and a second lens having a negative refractive power and a further lens (L 3 ) having positive refractive power,
a second group of lenses (G 2 ) having overall positive refractive power, comprising three cemented lenses (L 4 , L 5 , L 6 ),
a third group of lenses (G 3 ) having overall negative refractive power, comprising three cemented lenses (L 7 , L 8 , L 9 ), wherein the side of the third group of lenses that faces the image plane is convex,
a fourth group of lenses (G 4 ), comprising a lens (L 10 ) with positive refractive power and a cemented group of two lenses (L 11 , L 12 ) including a third lens having positive refractive power and a fourth lens having negative refraction power, and
a fifth group of lenses (G 5 ), comprising two lenses (L 13 , L 14 ) in a cemented group including a fifth lens having negative refractive power and a sixth lens having positive refractive power.
2. A microscope objective according to claim 1 , in which the magnitude of the focal length of the second group of lenses (G 2 ) is greater than or about equal to 15 mm.
3. A microscope objective according to claim 1 , in which the magnitude of the focal length of the third group of lenses (G 3 ) is greater than or about equal to 20 mm.
4. A microscope objective according to claim 1 , in which the magnitudes of the focal lengths of the lenses (L 5 , L 8 ) are each greater than or about equal to 20 mm.
5. A microscope objective according to claim 1 , built as an immersion objective, which is planapochromatically corrected within a spectral range from 365 nm to 850 nm, and which makes possible an enlargement of about 40× with an intermediate image of 2 y′ about equal to 25 mm and an aperture of about 1.2 with a working distance less than or equal to about 0.28 mm (plus cover glass), meeting the following criteria wherein radii are represented by r, thicknesses are represented by D and distances are represented by A in mm, refractive indices are represented by n e at a wavelength of 546.07 nm and Abbe numbers are represented by ν e as follows:
Object level
r
D
A
ne
v e
G1
∞
L1
0.82
1.46008
67.7
−0.892
L2
3.24
1.88815
40.5
−3.351
0.06
−13.143
L3
2.8
1.53019
76.6
−5.957
0.16
G2
11.965
L4
6.15
1.53430
48.6
−10.291
L5
0.95
1.64132
42.2
18.566
L6
3.87
1.43985
94.5
−15.8495
0.06
G3
46.9796
L7
3.15
1.43985
94.5
−12.496
L8
0.95
1.73739
51.2
8.7856
L9
5.18
1.43985
94.5
−25.2995
0.16
G4
11.8839
L10
5.1
1.45720
89.9
−43.0888
0.122
7.606
L11
5.95
1.53019
76.6
−17.151
L12
0.9
1.64132
42.2
4.529
5.196
G5
−4.598
L13
0.92
1.62247
63.2
−10.82
L14
2.07
1.62408
36.1
−6.2197
126.8
6. A microscope objective according to claim 1 , built as an immersion objective, which is planapochromatically corrected within a spectral range from 365 nm to 850 nm and which makes possible an enlargement of about 40× with an intermediate image of 2 y′ about equal to 25 mm, and an aperture of about 1.1 with a working distance less than or equal to about 0.62 mm (plus a cover glass), meeting the following criteria wherein radii are represented by r, thicknesses are represented by D and distances are represented by A in mm, refractive indices are represented by n e with a wavelength of 546.07 nm and Abbe numbers are represented by ν e :
Object level
r
D
A
ne
v e
G1
∞
L1
0.86
1.46008
67.7
−1.06
L2
3.7
1.88815
40.5
−3.813
0.06
−15.732
L3
2.8
1.48794
84.1
−6.778
0.16
G2
13.046
L4
6
1.53430
48.6
−10.745
L5
0.95
1.64132
42.2
21.9103
L6
4
1.43985
94.5
−15.2898
0.067
G3
23.207
L7
4
1.43985
94.5
−11.965
L8
0.95
1.73739
51.2
8.913
L9
4.2
1.43985
94.5
−40.0981
0.166
G4
11.141
L10
3.9
1.43985
94.5
−60.4312
0.123
7.829
L11
5.37
1.48794
84.1
−18.836
L12
2.03
1.61664
44.3
4.598
4.494
G5
−4.468
L13
1.05
1.62247
63.2
−12.6822
L14
2.51
1.65803
39.4
−6.541
96.378