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US 4,182,550 AGranted
Modified gauss type lens system
AssigneeMinolta Camera Kabushiki Kaisha
InventorTamikazu Yamaguchi
Life of this patent
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Abstract
An improved Gauss type lens system having a relatively large aperture ratio is provided. The lens system comprises seven components between object and image as follows; a first positive meniscus lens element, a second positive meniscus lens element, a third negative meniscus lens element, a fourth meniscus shaped doublet, a fifth positive meniscus lens element, and a sixth positive lens element. The entire lens system is capable of providing a relative aperture of F No. 1.2, an angle of view of 50.degree. and a back focus at least 0.7 times the overall focal length of the lens system.
Claims4
A modified Gauss type lens system comprising six separate lens groups consisting, consecutively from the object to the image side, of:
- a first front group consisting of a positive meniscus single lens element convex to the object side;
- a second group consisting of a positive meniscus single lens element convex to the object side;
- a third group consisting of a negative meniscus single lens element convex to the object side;
- a fourth group consisting of a meniscus shaped doublet element concave to the object side formed by cementing negative and positive sub-elements;
- a fifth group consisting of a positive meniscus single lens element concave to the object side;
- and
- a sixth rear group consisting of a positive single lens element, wherein the lens system fulfills the following conditions:
- -0.4<(.PHI..sub.4 +.PHI..sub.5)f<-0.24
- -1.21<(.PHI..sub.1 +.PHI..sub.3)/.PHI..sub.6 <-1.12
- -1.21<(.PHI..sub.9 +.PHI..sub.11)/.PHI..sub.7 <-1.13
- 0.85<(D.sub.7 +D.sub.8 +D.sub.9 +D.sub.10)/(D.sub.1 +D.sub.2 +D.sub.3 +D.sub.4 +D.sub.5)<1.1
- N.sub.3 <1.67, N.sub.4 <1.67
- .nu..sub.4 <.nu..sub.3
- -0.1<f/R.sub.8 <0.2
- wherein:
- R.sub.i represents the radius of curvature of the i-th refractive surface counted from the object side;
- D.sub.i represents the i-th axial distance (i.e., airspace or lens thickness) counted from the object side;
- N.sub.i represents the refractive index with respect to d-line of the i-th glass material counted from the object side;
- .nu..sub.i represents the Abbe number of the i-th glass material counted from the object side;
- .PHI..sub.i represents the refractive power of the i-th refractive surface counted from the object side, the refractive power .PHI..sub.i being defined by the radius of curvature R.sub.i of the i-th refractive surface, the refractive index n of the medium on the object side of the i-th refractive surface and the refractive index n' of the medium on the image side of the i-th refractive surface as follows:
- .PHI..sub.i =(n'-n)/R.sub.i ;
- and
- f represents the focal length of the whole lens system.
20 more elements
An improved Gauss type lens system comprising the following design parameters:
- ______________________________________ f = 100 1 :
- 1.2 2.omega.== 46.degree. Radius of Axial Refractive Abbe Curvature Distance Index Number ______________________________________ R.sub.1 = 88.05 D.sub.1 = 11.0 N.sub.1 = 1.7885 .nu..sub.1 = 45.7 R.sub.2 = 404.87 D.sub.2 = 0.44 R.sub.3 = 51.06 D.sub.3 = 10.0 N.sub.2 = 1.7856 .nu..sub.2 = 42.8 R.sub.4 = 80.10 D.sub.4 = 3.7 R.sub.5 = 99.43 D.sub.5 = 3.6 N.sub.3 = 1.7174 .nu..sub.3 = 29.4 R.sub.6 = 33.09 D.sub.6 = 32.13 R.sub.7 = -35.98 D.sub.7 = 3.5 N.sub.4 32 1.7618 .nu..sub.4 = 26.6 R.sub.8 = 519.44 D.sub.8 = 16.7 N.sub. 5 = 1.7885 .nu..sub.5 = 45.7 R.sub.9 = -59.97 D.sub.9 = 0.3 R.sub.10 = -335.50 D.sub.10 = 10.4 N.sub.6 = 1.7885 .nu..sub.6 = 45.7 R.sub.11 = -71.84 D.sub.11 = 0.31 R.sub.12 = 208.23 D.sub.12 = 5.5 N.sub.7 = 1.7495 .nu..sub.7 = 50.1 R.sub.13 = -513.55 ______________________________________ where the Back Focal Distance f.sub.b ' = 71.9
An improved Gauss type lens system comprising the following design parameters:
- ______________________________________ f = 100 1 :
- 1.4 2.omega. = 46.degree. Radius of Axial Refractive Abbe Curvature Distance Index Number ______________________________________ R.sub.1 = 75.00 D.sub.1 = 10.0 N.sub.1 = 1.7885 .nu..sub.1 = 45.7 R.sub.2 = 314.55 D.sub.2 = 0.3 R.sub.3 = 48.50 D.sub.3 = 8.4 N.sub.2 = 1.7650 .nu..sub.2 = 46.3 R.sub.4 = 76.46 D.sub.4 = 4.2 R.sub.5 = 105.61 D.sub.5 = 4.0 N.sub.3 = 1.7006 .nu..sub.3 = 30.1 R.sub.6 = 30.38 D.sub.6 = 29.3 R.sub.7 = -32.49 D.sub.7 = 2.8 N.sub.4 = 1.7552 .nu..sub.4 = 27.5 R.sub.8 = 800.0 D.sub.8 = 11.2 N.sub.5 = 1.7440 .nu..sub.5 = 45.0 R.sub.9 = -56.32 D.sub.9 = 0.3 R.sub.10 = -232.68 D.sub.10 = 9.1 N.sub.6 = 1.7810 .nu..sub.6 = 44.5 R.sub.11 = -57.45 D.sub.11 = 0.3 R.sub.12 = 482.00 D.sub.12 = 5.2 N.sub.7 = 1.7200 .nu..sub.7 = 50.2 R.sub.13 = -164.25 ______________________________________ where the Back Focal Distance f.sub.b ' = 72.35
An improved Gauss type lens system comprising the following design parameters:
- ______________________________________ f = 100 1 :
- 1.8 2.omega. = 52.degree. Radius of Axial Refractive Abbe Curvature Distance Index Number ______________________________________ R.sub.1 = 117.07 D.sub.1 = 8.99 N.sub.1 = 1.7885 .nu..sub.1 = 45.7 R.sub.2 = 1226.07 D.sub.2 = 0.36 R.sub.3 = 44.18 D.sub.3 = 8.02 N.sub.2 = 1.8070 .nu..sub.2 = 39.8 R.sub.4 = 72.96 D.sub.4 = 3.10 R.sub.5 = 100.86 D.sub.5 = 2.79 N.sub.3 = 1.7174 .nu..sub.3 = 29.4 R.sub.6 = 34.49 D.sub.6 = 20.0 R.sub.7 = -36.50 D.sub.7 = 3.01 N.sub.4 = 1.7400 .nu..sub.4 = 28.3 R.sub.8 = 704.64 D.sub.8 = 12.01 N.sub. 5 = 1.7883 .nu..sub.5 = 47.3 R.sub.9 = -64.77 D.sub.9 = 0.35 R.sub.10 = -167.88 D.sub.10 = 6.20 N.sub.6 = 1.7885 .nu..sub.6 = 45.7 R.sub.11 = -69.80 D.sub.11 = 0.33 R.sub.12 = -4791.6 D.sub.12 = 5.0 N.sub.7 = 1.7810 .nu..sub.7 = 44.5 R.sub.13 = -112.46 ______________________________________ where the Back Focal Distance f.sub.b ' = 79.8
Dependencies are inferred from the claim text.