High-aperture immersion objective
A high-aperture immersion objective, in particular for confocal applications in fluorescence microscopy and for TIRF applications, having three subsystems of lenses and/or lens groups. The design of the subsystems has made it possible for a relatively large object field of 0.25 mm to be present in the case of a high-resolution numerical aperture of 1.49. Furthermore, improved transparency is possible up to a wavelength of 340 nm.
1. A high-aperture immersion objective, adapted for confocal applications in fluorescence microscopy and for total internal reflection fluorescence (TIRF) applications, comprising:
three subsystems, each of the three subsystems comprising lenses and/or lens groups, the three subsystems including a first subsystem, a second subsystem and a third subsystem, wherein proceeding from the object side,
the first subsystem comprises a double cemented element with a high positive refractive power and three following collecting lenses, including a first collecting lens, a second collecting lens and a third collecting lens, wherein the double cemented element has a plano surface facing the object side and wherein the first collecting lens is followed by a first meniscus lens bent toward the object side and having a negative refractive power,
further wherein the second subsystem comprises a double cemented element with a low positive refractive power and a triple cemented element with a low positive refractive power, wherein the double cemented element comprises a fifth collecting lens and a first diverging lens and the triple cemented element has a second diverging lens encompassed by a sixth collecting lens and a seventh collecting lens, and
further wherein the third subsystem comprises a second meniscus lens and a fifth meniscus lens with a low positive refractive power, which surround a triple cemented element with a very high negative refractive power, the triple cemented element including a third meniscus lens and a fourth meniscus lens and a third diverging lens.
2. The high-aperture immersion objective according to claim 1 , wherein the second collecting lens, the third collecting lens and a fourth collecting lens of the first subsystem are made of Fluorkron glass, wherein the second collecting lens is made of a glass with a refractive index greater than 1.59 and a side of the second collecting lens facing away from the object side comprises a hyper-hemispherical surface.
3. The high-aperture immersion objective according to claim 1 , wherein the fifth collecting lens of the double cemented element of the second subsystem is made of Fluorkron glass or CaF2 and the second diverging lens is made of short flint glass.
4. The high-aperture immersion objective according to claim 1 , wherein the second diverging lens of the triple cemented element of the second subsystem is made of short flint glass, and further wherein the sixth collecting lens and the seventh collecting lens are each made of Fluorkron glass or calcium fluoride (CaF2).
5. The high-aperture immersion objective according to claim 1 , wherein at least one of the third meniscus lens the fourth meniscus lens and/or the third diverging lens of the triple cemented element of the third subsystem has an Abbe number less than 29.5.
6. The high-aperture immersion objective according to claim 1 , having the following design data with radii of curvature r being designated in mm, thicknesses d designated in mm, refractive indices n e , Abbe numbers ν e , and the use of an oil immersion at a magnification of 100, a numerical aperture of 1.49, a cover glass thickness of 0.17 mm, and a working distance of 0.12 mm:
Refractive
Radius of
index n e
Abbe
SurfaceFL
curvature r
Thickness d
Oil immersion
number ν e
1
infinite
1.000
1.525
59.2
2
−1.413
1.900
1.888
40.5
3
−3.026
0.100
4
−4.038
2.700
1.594
68.0
5
−4.004
0.100
6
−62.194
4.300
1.440
94.5
7
−9.567
0.100
8
28.800
5.240
1.440
94.5
9
−18.700
0.100
10
15.962
6.700
1.440
94.5
11
−13.143
1.090
1.617
44.3
12
70.796
0.100
13
8.1756
4.319
1.440
94.5
14
52.334
1.000
1.725
34.5
15
5.332
5.292
1.440
94.5
16
−12.320
0.300
17
8.5343
1.365
1.594
68.0
18
29.639
0.992
19
−6.451
3.487
1.723
29.3
20
−4.340
2.205
1.839
42.5
21
−3.301
1.675
1.737
51.2
22
4.598
1.491
23
−3.078
2.323
1.743
32.0
24
−3.9243
7. The high-aperture immersion objective according to claim 1 , having the following design data with radii of curvature r designated in mm, thicknesses d designated in mm, refractive indices n e , Abbe numbers ν e , and the use of an oil immersion at a magnification of 100, a numerical aperture of 1.49, a cover glass thickness of 0.17 mm, and a working distance of 0.11 mm:
Refractive
Abbe
Radius of
index n e
number
Surface FL
curvature r
Thickness d
Oil immersion
ν e
1
infinite
1.024
1.525
59.2
2
−1.402
1.220
1.888
40.5
3
−2.548
0.100
4
−3.924
2.750
1.635
63.5
5
−3.704
0.216
6
−110.60
5.000
1.440
94.5
7
−9.858
0.100
8
39.809
5.540
1.440
94.5
9
−18.303
0.100
10
20.834
7.000
1.440
94.5
11
−12.230
1.100
1.617
44.3
12
−44.344
0.100
13
8.913
5.400
1.440
94.5
14
−30.506
0.900
1.725
34.5
15
5.870
6.670
1.440
94.5
16
−10.146
0.219
17
7.802
1.800
1.594
68.0
18
19.670
1.150
19
−4.433
1.080
1.725
34.5
20
−21.287
1.800
1.839
42.5
21
−2.820
0.700
1.737
51.2
22
4.279
1.600
23
−2.820
2.401
1.762
27.4
24
−3.704