USH1763HExpiredUtilityPatentIndex 73
Microscope objective lens
Est. expiryFeb 28, 2016(expired)· nominal 20-yr term from priority
Inventors:MIZUSAWA MASAYUKI
G02B 27/0068G02B 21/02
73
PatentIndex Score
8
Cited by
12
References
8
Claims
Abstract
Apochromatic-type microscope objective lenses are disclosed having a high numeral aperture number with few component lenses. The objective lenses are operable to correct any of various aberrations arising due to use of the objective lens with cover glasses having variable thickness. The objective lenses comprise a first positive lens group comprising a positive meniscus lens with a concave surface facing objectwise, a second positive lens group comprising a positive cemented lens in which the cemented surface has negative refractive power and a negative cemented lens in which the cemented surface has positive refractive power, and a third (negative) lens group comprising at least one cemented lens. The second and third lens groups are movable on the optical axis relative to the first lens group so as to facilitate correction of aberrations arising from use of cover glasses having variable thickness.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1. A microscope objective lens comprising, on an optical axis from the object side to the image side: (a) a first lens group (G1) having a positive refractive power, a second lens group (G2) having a positive refractive power, and a third lens group (G3) having a negative refractive power; (b) the first lens group (G1) comprising first, second, and third positive meniscus lenses each having a concave surface facing the object side; (c) the second lens group (G2) comprising a first cemented lens (L21) including a negative lens (L2n) cemented to a positive lens (L2p) and a cemented surface having a negative refractive power, and a second cemented lens (L22) including a cemented surface having a positive refractive power; (d) the third lens group (G3) comprising a cemented lens consisting of a biconcave lens and a biconvex lens; (e) the second and third lens groups being movable along the optical axis relative to the first lens group so as to correct aberrations arising as a result of using the objective lens with a cover glass having variable thickness; and (f) the lens satisfying the following conditional expressions: 0.33<n.sub.2n -n.sub.2p 0.02<(D.sub.12)/f<1.3 wherein n 2n is the refractive index (relative to the D-line) of the negative lens (L2n), n 2p is the refractive index (relative to the D-line) of the positive lens (L2p), (D 12 ) is the axial air space between the first lens group (G1) and the second lens group (G2), and f is the focal length of the objective lens.
2. The microscope objective lens of claim 1, having a mangification of 40×.
3. The microscope objective lens of claim 1, further having the following characteristics: (a) a focal length f=5.0 mm (b) a numerical aperture NA=0.95 (c) a magnification β=40× (d) a working distance WD=0.14 mm (e) surfaces, curvature radii (r), inter-surface axial distances (d), indices of refraction (n d ), and Abbe numbers (v d ), as follows: ______________________________________
Surface No.
r (mm) d (mm) n.sub.d
ν.sub.d
______________________________________
1 -2.1418 4.30 1.6935
53.76
2 -3.7147 0.10
3 -15.3747 3.30 1.4978
82.52
4 -7.6264 0.15
5 -34.5141 3.75 1.4978
82.52
6 -12.3011 0.10
7 34.7490 1.15 1.6889
31.08
8 12.2878 7.50 1.4978
95.57
9 -12.2878 (d.sub.9 = D.sub.12 = variable)
10 38.3740 1.15 1.8052
25.35
11 8.4327 6.80 1.4339
95.57
12 -33.7370 1.80
13 203.9400 5.50 1.8052
25.41
14 -10.9804 1.60 1.4339
95.57
15 124.9710 6.60
16 -27.1710 1.00 1.7668
46.80
17 10.4119 3.00 1.5481
45.87
18 -60.8420 150
______________________________________
4. The microscope objective lens of claim 1, wherein the first lens group (G1) further comprises a cemented lens including a negative meniscus lens cemented to a biconvex lens, the cemented lens being situated imagewise of the first, second, and third positive meniscus lenses.
5. The microscope objective lens of claim 1, exhibiting a numerical aperature of at least 0.85.
6. The microscope objective lens of claim 1, wherein the first lens group (G1) further comprises a cemented lens including a negative meniscus lens cemented to a biconvex lens, the cemented lens being situated imagewise of the first positive meniscus lens.
7. The microscope objective lens of claim 1, wherein the second cemented lens (L22) in the second lens group (G2) comprises a biconvex lens cemented to a biconcave lens.
8. The microscope objective lens of claim 1, further having the following characteristics: (a) a focal length f=5.0 mm (b) a numerical aperture NA=0.9 (c) a magnification β=40× (d) a working distance WD=0.14 mm (e) surfaces, curvature radii (r), inter-surface axial distances (d), indices of refraction (n d ), and Abbe numbers (v d ), as follows: ______________________________________
Surface No.
r (mm) d (mm) n.sub.d
ν.sub.d
______________________________________
1 -2.1461 4.25 1.6935
53.76
2 -3.7862 0.10
3 -15.7896 3.30 1.4978
82.52
4 -7.6264 0.15
5 -38.7484 3.75 1.4978
82.52
6 -12.2561 0.10
7 34.7490 1.20 1.6889
31.08
8 12.2881 7.50 1.4978
95.57
9 -12.2933 (d.sub.9 = D.sub.12 = variable)
10 43.1326 1.15 1.8052
25.35
11 8.4532 6.80 1.4339
95.57
12 -32.0003 1.80
13 -411.5836
5.50 1.8052
25.41
14 -10.5541 1.60 1.4339
95.57
15 132.4293 6.60
16 41.9894 3.00 1.5481
45.87
17 10.7049 1.00 1.7668
46.80
18 29.1202 150
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