Claims
- 1. An inverse telescopic wide angle lens comprising:
- a diaphragm;
- a front lens group of an integral positive or negative refractive power, positioned in the object side in front of said diaphragm and having a first lens group of a negative refractive power including a negative lens of which an image-side air-contacting surface is formed as an aspherical surface concave to the image side, and a second lens group of a positive refractive power positioned between said first lens group and said diaphragm; and
- a rear lens group of an integral positive refractive power, positioned behind said diaphragm and having plural lenses;
- wherein said negative lens in said first lens group is so constructed that the absolute value of the refractive power of said concave surface on the optical axis is larger than that of the refractive power of the surface at the object side on the optical axis, that the curvature of said concave surface decreases monotonously with the distance from the optical axis, and that the form of said concave surface of said negative lens at the image side, when represented by an equation:
- x=Cy.sup.2 /{1+(1-.kappa.C.sup.2 y.sup.2).sup.1/2 }+C.sub.4 y.sup.4 +C.sub.6 y.sup.6 + . . .
- defining the axial distance x from the peak point of a curve constituting said aspherical surface as a function of the distance y of said curve from the optical axis, with a curvature C at said peak point of the curve, a conical constant .kappa. and aspherical constants C.sub.4, C.sub.6, . . . , satisfies a condition -5<.kappa.<0.5; and
- said aspherical surface satisfies a condition:
- 0. 8<.vertline.h.sub.p /r.sub.A .vertline.<1.5
- wherein r.sub.A is the paraxial radius of curvature of said aspherical surface and h.sub.p is the height, from the optical axis, of the crossing point of the principal ray at the maximum image angle on said aspherical surface.
- 2. An inverse telescopic wide angle lens according to claim 1, wherein said first lens group is so constructed as to further satisfy a condition:
- 0.4<.vertline.f.sub.1 /f.vertline.<2.0
- wherein f is the focal distance of the entire lens system, and f.sub.1 is the focal distance of said first lens group.
- 3. An inverse telescopic wide angle lens according to claim 1, wherein the concave surface, at the image side, of said negative lens in said first lens group is formed as a parabolic surface satisfying the following condition:
- x=y.sup.2 /2.multidot.r.sub.2 (.kappa.=0, C.sub.4, C.sub.6, . . . =0)
- defining the distance x along the optical axis from the peak point of said curved surface as a function of distance y of said curved surface from the optical axis, wherein r.sub.2 is the radius of curvature at said peak point of the curved surface.
- 4. An inverse telescopic wide angle lens according to claim 1, wherein said first lens group in said front lens group is composed solely of a negative meniscus lens convex to the object side, and having a concave surface at the image side, formed as an aspherical surface of which curvature decreases monotonously with the distance from the optical axis; said second lens group is composed, in the order from the object side, of an adhered lens consisting of a negative meniscus lens convex to the object side and a positive meniscus lens convex to the object side, and a biconvex positive lens; and said rear lens group is composed, in the order from the object side, of an adhered lens consisting of a positive meniscus lens convex to the image side and a negative meniscus Lens convex to the image side, an adhered lens consisting of a positive meniscus Lens convex to the image side and a biconcave negative lens, a positive meniscus lens convex to the image side, and a biconvex positive lens having a surface of a stronger curvature at the image side.
- 5. An inverse telescopic wide angle lens according to claim 1, wherein said first lens group in said front lens group is composed, in the order from the object side, of a negative meniscus lens convex to the object side, having a concave surface at the image side, formed as an aspherical surface of which curvature decreases monotonously with the distance from the optical axis, an adhered lens consisting of a biconvex positive lens and a negative meniscus lens convex to the image side, and a negative meniscus lens convex to the object side; said second lens group is composed, in the order from the object side, of an adhered lens consisting of a biconvex positive lens and a biconcave negative lens, and a biconvex positive lens; and said rear lens group is composed, in the order from the object side, of an adhered lens consisting of a biconvex positive lens and a biconcave negative lens, an adhered lens consisting of a biconcave negative lens and a biconvex positive lens, and a biconvex positive lens having a surface of a stronger curvature at the image side.
- 6. An inverse telescopic wide angle lens according to claim 1, wherein said first lens group in said front lens group is composed, in the order from the object side, of a negative meniscus lens convex to the object side, having a concave surface at the image side, formed as an aspherical surface of which curvature decreases monotonously with the distance from the optical axis, an adhered lens consisting of a negative meniscus lens convex to the object side and a positive meniscus lens convex to the object side, and a negative meniscus lens convex to the object side; said second lens group is composed, in the order from the object side, of an adhered lens consisting of a negative meniscus lens convex to the object side and a positive meniscus lens convex to the object side, and a positive meniscus lens convex to the object side; and said rear lens group is composed, in the order from the object side, of an adhered lens consisting of a biconvex lens and a biconcave lens, an adhered lens consisting of a biconcave lens and a biconvex lens, and a biconvex positive lens having a surface of a stronger curvature at the image side.
- 7. An inverse telescopic wide angle lens according to claim 1, wherein said first lens group in said front lens group is composed, in the order from the object side, of a negative meniscus lens convex to the object side, having a concave surface at the image side, formed as an aspherical surface of which curvature decreases monotonously with the distance from the optical axis, an adhered lens consisting of a negative .meniscus lens convex to the object side and a biconvex positive lens, and a negative meniscus lens convex to the object side; said second lens group is composed, in the order from the object side, of an adhered lens consisting of a negative meniscus lens convex to the object side and a positive meniscus lens convex to the object side, and a biconvex positive lens; and said rear lens group is composed, in the order from the object side, of an adhered lens consisting of a biconvex positive lens and a biconcave negative lens, an adhered lens consisting of a negative meniscus lens convex to the object side and a biconvex positive lens, and a biconvex positive lens having a surface of a stronger curvature at the image side.
- 8. An inverse telescopic wide angle lens according to claim 1, wherein said first lens group in said front lens group is composed solely of an adhered lens consisting of a planoconvex positive lens convex to the object side and a planoconcave negative lens having a concave surface at the image side, formed as an aspherical surface of which curvature decreases monotonously with the distance from the optical axis; said second lens group is composed, in the order from the object side, of an adhered lens consisting of a negative meniscus lens convex to the object side and a positive meniscus lens convex to the object side, and a biconvex positive lens; and said rear lens group is composed, in the order from the object side, of an adhered lens consisting of a positive meniscus lens convex to the image side and a negative meniscus lens convex to the image side, a biconcave negative lens, a positive meniscus lens convex to the image side, and a biconvex positive lens having a surface of a stronger curvature at the image side.
- 9. An inverse telescopic wide angle lens according to claim 1, wherein said first lens group in said front lens group is composed solely of a negative meniscus lens convex to the object side and having a concave surface at the image side, formed as an aspherical surface of which curvature decreases monotonously with the distance from the optical axis; said second lens group is composed, in the order from the object side, of an adhered lens consisting of a negative meniscus lens convex to the object side and a biconvex positive lens, and an adhered lens consisting of a biconvex positive lens and a negative meniscus lens concave to the object side; and said rear lens group is composed, in the order from the object side, of an adhered lens consisting of a positive meniscus lens convex to the image side and a biconcave negative lens, a positive meniscus lens convex to the image side, and a biconvex positive lens having a surface of a stronger curvature at the image side.
- 10. An inverse telescopic wide angle lens according to claim 1, constructed according to the following data, wherein r.sub.i is the radius of curvature of an i-th surface (i=1, 2, 3, . . . ) numbered from the object side, d.sub.i is the axial distance between i-th and (i+1)-th lens surfaces, n.sub.di is the refractive index for d-line, of the medium between the i-th and (i+1)-th surfaces, and .nu..sub.di is Abbe's number of the medium between the i-th and (i+1)-th surfaces (Abbe's number for air being left blank), F.sub.NO is the F number, and asterisk (*) indicates an aspherical surface:
- ______________________________________f = 100, F.sub.NO = 2.8, 2.theta. = 100.degree.i r.sub.i d.sub.i n.sub.di .nu..sub.di______________________________________1 736.951 5.490 1.77279 49.45*2 99.559 105.968 1.000003 227.925 26.847 1.77279 45.454 86.498 106.517 1.60342 38.035 848.627 1.647 1.000006 159.826 43.924 1.60342 38.037 -6698.393 16.471 1.000008 -3216.170 19.766 1.57501 41.429 -58.390 10.981 1.74810 52.3010 -210.440 11.530 1.0000011 -283.318 28.002 1.80411 46.5512 -104.074 5.490 1.80518 25.3513 333.225 7.686 1.0000014 -226.181 14.824 1.62041 60.1415 -93.959 1.098 1.0000016 458.139 19.217 1.62041 60.1417 -219.467 205.941 1.00000______________________________________ .vertline.h.sub.p /r.sub.A .vertline. = 0.900 conical constant .kappa. = 0.
- 11. An inverse telescopic wide angle lens according to claim 1, constructed according to the following data, wherein r.sub.i is the radius of curvature of an i-th surface (i=1, 2, 3 . . . ) numbered from the object side, d.sub.i is the axial distance between i-th and (i+1)-th lens surfaces n.sub.di is the refractive index, for d-line, of the medium between the i-th and (i+1)-th surfaces, and .nu..sub.di is Abbe's number of the medium between the i-th and (i+1)-th surfaces (Abbe's number for air being left blank), F.sub.NO is the F number, and asterisk (*) indicates an aspherical surface:
- ______________________________________f = 100, F.sub.NO = 3.5 2.theta. = 110.degree.i r.sub.i d.sub.i n.sub.di .nu..sub.di______________________________________1 1141.843 9.868 1.77279 49.45*2 94.601 85.526 1.000003 590.915 85.449 1.61293 36.984 -210.851 71.236 1.71300 53.935 -495.018 1.315 1.000006 139.541 9.868 1.65160 58.507 97.296 23.026 1.000008 176.250 39.473 1.62004 36.279 -201.482 84.210 1.80411 46.5510 208.521 1.315 1.0000011 131.381 13.157 1.58144 40.7612 -540.218 24.342 1.0000013 211.677 19.736 1.51680 64.1014 -96.540 6.578 1.79631 40.9015 243.213 7.894 1.0000016 -3841.914 4.605 1.79504 28.5717 159.372 34.210 1.51680 64.1018 -110.558 1.315 1.0000019 1646.110 23.026 1.51680 64.1020 -172.890 250.995 1.00000______________________________________ .vertline.h.sub.p /r.sub.A .vertline. = 1.194 conical constant .kappa. = 0.
- 12. An inverse telescopic wide angle lens according to claim 1, constructed according to the following data, wherein r.sub.i is the radius of curvature of an i-th surface (i=1, 2, 3 . . . ) numbered from the object side, d.sub.i is the axial distance between i-th and (i+1)-th lens surfaces, n.sub.di is the refractive index, for d-line, of the medium between the i-th and (i+1)-th surfaces, and .nu..sub.di is Abbe's number of the medium between the i-th and (i+1)-th surfaces (Abbe's number for air being left blank), F.sub.NO is the F number, and asterisk (*) indicates an aspherical surface:
- ______________________________________f = 100, F.sub.NO = 3.5, 2.theta. = 110.degree.i r.sub.i d.sub.i n.sub.di .nu..sub.di______________________________________1 1333.575 9.868 1.74810 52.30*2 106.710 98.305 1.000003 221.380 23.026 1.71300 53.934 138.762 106.382 1.59507 35.515 923.259 1.315 1.000006 192.744 9.868 1.65160 58.507 109.801 32.894 1.000008 187.842 16.447 1.74810 52.309 88.457 132.099 1.62004 36.2710 356.513 1.315 1.0000011 139.600 13.157 1.51680 64.1012 348.181 24.342 1.0000013 178.124 19.736 1.51680 64.1014 -108.565 6.578 1.79668 45.3715 311.912 11.184 1.0000016 -2911.027 4.605 1.80384 33.9217 158.548 34.210 1.51680 64.1018 -112.805 1.315 1.0000019 342.313 29.605 1.51680 64.1020 -239.277 258.613 1.00000______________________________________ .vertline.h.sub.p /r.sub.A .vertline. = 1.348 conical constant .kappa. = 0.
- 13. An inverse telescopic wide angle lens according to claim 1, constructed according to the following data, wherein r.sub.i is the radius of curvature of an i-th surface (i=1, 2, 3, . . . ) numbered from the object side, d.sub.i is the axial distance between i-th and (i+1)-th lens surfaces, n.sub.di is the refractive index for d-line, of the medium between the i-th and (i+1)-th surfaces .nu..sub.di is Abbe's number of the medium between the i-th and (i+1)-th faces (Abbe's number for air being left blank), F.sub.NO is the F number, and asterisk (*) indicates as aspherical surface:
- ______________________________________f = 100, F.sub.NO = 2.8, 2.theta. = 110.degree.i r.sub.i d.sub.i n.sub.di .nu..sub.di______________________________________1 1319.491 9.868 1.74810 52.30*2 108.017 82.236 1.000003 288.869 23.026 1.71300 53.934 147.353 108.552 1.59507 35.515 -1375.554 1.315 1.000006 187.777 9.868 1.65160 58.507 99.315 32.894 1.000009 212.517 16.447 1.74810 52.309 83.032 114.728 1.62004 36.2710 217.920 1.315 1.0000011 146.295 13.157 1.51680 64.1012 -986.512 24.342 1.0000013 120.646 19.736 1.51680 64.1014 -411.297 6.578 1.79668 45.3715 150.107 11.184 1.0000016 800.896 4.605 1.80384 33.9217 127.565 34.210 1.51680 64.1018 -136.158 1.315 1.0000019 589.798 29.605 1.51680 64.1020 -220.870 248.442 1.00000______________________________________ .vertline.h.sub.p /r.sub.A .vertline. = 1.211 conical constant .kappa. = 0.
- 14. An inverse telescopic wide angle lens according to claim 1, constructed according to the following data, wherein r.sub.i is the radius of curvature of an i-th surface (i=1, 2, 3, . . . ) numbered from the object side, d.sub.i is the axial distance between i-th and (i+1)-th lens surfaces, n.sub.di is the refractive index, for d-line, of the medium between the i-th and (i+1)-th surfaces, .nu..sub.di is Abbe's number of the medium between the i-th and (i+1)-th surfaces (Abbe's number for air being left blank), F.sub.NO is the F number, and asterisk (*) indicates an aspherical surface:
- ______________________________________f = 100, F.sub.NO = 2.8, 2.theta. = 100.degree.i r.sub.i d.sub.i n.sub.di .nu..sub.di______________________________________1 765.025 21.857 1.78470 26.052 .infin. 5.464 1.77279 49.45*3 97.480 105.464 1.000004 191.485 24.590 1.77279 49.455 81.967 107.650 1.60342 38.026 497.718 1.639 1.000007 157.923 43.715 1.62374 47.108 -8253.032 16.393 1.000009 -790.556 19.672 1.58913 61.0910 -55.464 10.928 1.74443 49.5211 -183.059 11.475 1.0000012 -250.013 29.508 1.80518 25.3513 353.551 10.928 1.0000014 -245.901 14.754 1.62041 60.1415 -98.360 1.092 1.0000016 398.906 20.764 1.62041 60.1417 -216.742 201.662 1.00000______________________________________ .vertline.h.sub.p /r.sub.A .vertline. = 0.927 effective diameter .phi. 275 mm, 4 .multidot. f .multidot. tan.theta. = 416 mm, conical constant .kappa. = 0.
- 15. An inverse telescopic wide angle lens according to claim 1, constructed according to the following data, wherein r.sub.i is the radius of curvature of an i-th surface (i=1, 2, 3, . . . ) numbered from the object side, d.sub.i is the axial distance between i-th and (i+1)-th lens surfaces, n.sub.di is the refractive index, for d-line, of the medium between the i-th and (i+1)-th surfaces, .nu..sub.di is Abbe's number of the medium between the i-th and (i+1)-th surfaces (Abbe's number for air being left blank), F.sub.NO is the F number, and asterisk (*) indicates an aspherical surface:
- ______________________________________f = 100, F.sub.NO = 2.8, 2.theta. = 100.degree.i r.sub.i d.sub.i n.sub.di .nu..sub.di______________________________________1 979.796 5.413 1.77279 49.45*2 94.079 99.066 1.000003 276.586 29.774 1.77279 49.454 126.733 104.566 1.62004 36.275 -525.890 18.135 1.000006 169.788 43.307 1.57501 41.427 -71.525 10.826 1.74810 52.308 -3830.195 16.240 1.000009 -16113.440 37.352 1.77279 49.4510 -104.122 10.826 1.80518 25.3511 234.356 7.037 1.0000012 -303.505 14.616 1.62041 60.1413 -98.727 1.082 1.0000014 751.268 18.947 1.62041 60.1415 -212.510 206.762 1.00000______________________________________ .vertline.h.sub.p /r.sub.A .vertline. = 0.913 conical constant .kappa. = 0.
- 16. An inverse telescopic wide angle lens comprising:
- a diaphragm;
- a front lens group of an integral positive or negative refractive power, positioned in the object side in front of said diaphragm and having a first lens group of a negative refractive power including a negative lens of which an image-side air-contacting surface is formed as an aspherical surface concave to the image side, and a second lens group of a positive refractive power positioned between said first lens group and said diaphragm; and
- a rear lens group of an integral positive refractive power, positioned behind said diaphragm and having plural lenses;
- wherein said negative lens in said first lens group is so constructed that the absolute value of the refractive power of said concave surface on the optical axis is larger than that of the refractive power of the surface at the object side on the optical axis, that the curvature of said concave surface decreases monotonously with the distance from the optical axis, and that said aspherical surface satisfies a condition:
- 0.8<.vertline.h.sub.p /r.sub.A .vertline.<1.5
- wherein r.sub.A is the paraxial radius of curvature of said aspherical surface, and h.sub.P is the height, from the optical axis, of the crossing point of the principal ray at the maximum image angle on said aspherical surface.
- 17. An inverse telescopic wide angle lens according to claim 16, wherein said first lens group is so constructed as to further satisfy a condition:
- 0.7<.vertline.f.sub.1 /f.vertline.<1.28
- wherein f is the focal distance of the entire lens system, and f.sub.1 is the focal distance of said first lens group.
Priority Claims (3)
Number |
Date |
Country |
Kind |
3-207704 |
Aug 1991 |
JPX |
|
3-306683 |
Oct 1991 |
JPX |
|
5-037216 |
Feb 1993 |
JPX |
|
Parent Case Info
This is a continuation-in-part application of U.S. patent application Ser. No. 093,727 filed Jul. 20, 1993, which is a continuation of Ser. No. 931,347 filed Aug. 18, 1992, abandoned.
US Referenced Citations (4)
Foreign Referenced Citations (1)
Number |
Date |
Country |
62-78520 |
Apr 1987 |
JPX |
Continuations (1)
|
Number |
Date |
Country |
Parent |
931347 |
Aug 1992 |
|
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
93727 |
Jul 1993 |
|