Objective lens system for endoscopes
First Claim
1. An objective lens system for endoscopes comprising a first negative meniscus lens component having a concave surface on the image side, an aperture stop, a second positive meniscus lens component, a third biconvex lens component and a fourth positive cemented doublet component consisting of a positive lens element and a negative lens element, said lens system being so designed as to satisfy the following conditions:
- ##EQU2## wherein the reference symbol f represents total focal length of the entire lens system as a whole, the reference symbol f234 designates total focal length of said second, third and fourth lens components as a whole, the reference symbols r2 , r5 and r7 denote radii of curvature on the image side surface of said first lens component, image side surface of said second lens component and image side surface of said third lens component, the reference symbols n1 through n5 represent refractive indices of the respective lens elements and the reference symbols ν
1, ν
2 and ν
3 designate Abbe'"'"'s numbers of said first, second and third lens components respectively.
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Accused Products
Abstract
An objective lens system for endoscopes comprising a first negative meniscus lens component, a second positive meniscus lens component, a third biconvex lens component and a fourth positive cemented doublet component consisting of a positive lens element and a negative lens element, said lens system having a super-wide angle and favorably corrected aberrations, especially spherical aberration and lateral chromatic aberration.
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Citations
17 Claims
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1. An objective lens system for endoscopes comprising a first negative meniscus lens component having a concave surface on the image side, an aperture stop, a second positive meniscus lens component, a third biconvex lens component and a fourth positive cemented doublet component consisting of a positive lens element and a negative lens element, said lens system being so designed as to satisfy the following conditions:
- ##EQU2## wherein the reference symbol f represents total focal length of the entire lens system as a whole, the reference symbol f234 designates total focal length of said second, third and fourth lens components as a whole, the reference symbols r2 , r5 and r7 denote radii of curvature on the image side surface of said first lens component, image side surface of said second lens component and image side surface of said third lens component, the reference symbols n1 through n5 represent refractive indices of the respective lens elements and the reference symbols ν
1, ν
2 and ν
3 designate Abbe'"'"'s numbers of said first, second and third lens components respectively. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
- ##EQU2## wherein the reference symbol f represents total focal length of the entire lens system as a whole, the reference symbol f234 designates total focal length of said second, third and fourth lens components as a whole, the reference symbols r2 , r5 and r7 denote radii of curvature on the image side surface of said first lens component, image side surface of said second lens component and image side surface of said third lens component, the reference symbols n1 through n5 represent refractive indices of the respective lens elements and the reference symbols ν
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16. An objective lens system for endoscopes comprising a first negative meniscus lens component having a concave surface on the image side, an aperture stop, a second positive meniscus lens component, a third biconvex lens component and a fourth positive cemented doublet component consisting of a positive lens element and a negative lens element, said lens system having the following numerical data:
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space="preserve" listing-type="tabular">______________________________________ r.sub.1 = 28.7611 d.sub.1 = 0.4938 n.sub.1 = 1.58913 ν
.sub.1 = 60.97 r.sub.2 = 0.8457 d.sub.2 = 0.9877 r.sub.3 = ∞
d.sub.3 = 0.6173 r.sub.4 = -99,2330 d.sub.4 = 1.0494 n.sub.2 = 1.6968 ν
.sub.2 = 55.52 r.sub.5 = -2,1786 d.sub.5 = 0.1235 r.sub.6 = 9.2568 d.sub.6 = 1.1111 n.sub.3 = 1.6968 ν
.sub.3 = 55.52 r.sub.7 = -4.4531 d.sub.7 = 0.1235 r.sub.8 = 3.0441 d.sub.8 = 1.7284 n.sub.4 = 1.6180 ν
.sub.4 = 63.38 r.sub.9 = -1.6506 d.sub.9 = 0.4321 n.sub.5 = 1.84666 ν
.sub.5 = 23.90 r.sub.10 = -18.0296 f = 1.0, 1 = 15.0, S = 0.863 IH = 0.889, 2ω
= 117.08°
, Σ
P = 0 NA = 0.0129, f.sub.234 /f = 1.591 ##STR29## ______________________________________wherein the reference symbols r1 through r10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d1 through d9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n1 through n5 denote refractive indices of the respective lens elements, the reference symbols ν
1 through ν
5 represent Abbe'"'"'s numbers of the respective lens elements, the reference symbol 1 designates distance as measured from an object to be observed or photographed to the front surface of the lens system, the reference symbol S denotes distance as measured from the rear surface of the lens system to the image, the reference symbol IH represents height of the image, the reference symbol 2ω
designates field angle, the reference symbol Σ
P denotes Petzval'"'"'s sum, the reference sumbol NA represents numerical aperture, the reference symbol f represents total focal length of the entire lens system as a whole, and the reference symbol f234 designates total focal length of said second, third and fourth lens components as a whole.
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17. An objective lens system for endoscopes comprising a first negative meniscus lens component having a concave surface on the image side, an aperture stop, a second positive meniscus lens component, a third biconvex lens component and a fourth positive cemented doublet component consisting of a positive lens element and a negative lens element, said lens system having the following numerical data:
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space="preserve" listing-type="tabular">______________________________________ r.sub.1 = 80.059 d.sub.1 = 0.523 n.sub.1 = 1.726 ν
.sub.1 = 53.56 r.sub.2 = 0.945 d.sub.2 = 1.264 r.sub.3 = ∞
d.sub.3 = 0.376 r.sub.4 = -30.452 d.sub.4 = 1.076 n.sub.2 = 1.6968 ν
.sub.2 = 55.52 r.sub.5 = -2.227 d.sub.5 = 0.126 r.sub.6 = 12.588 d.sub.6 = 1.139 n.sub.3 = 1.51728 ν
.sub.3 = 69.56 r.sub.7 = -2.878 d.sub.7 = 0.126 r.sub.8 = 3.426 d.sub.8 = 1.965 n.sub.4 = 1.69249 ν
.sub.4 = 58.56 r.sub.9 = -1.557 d.sub.9 = 0.439 n.sub.5 = 1.92286 ν
.sub.5 = 21.29 r.sub.10 = -36.333 f = 1.0, l = 15.0, S = 1.05 IH = 0.89, 2ω
= 116.69°
, Σ
P = -0.036 NA = 0.0128, f.sub.234 /f = 1.666 ##STR30## ______________________________________wherein the reference symbols r1 through r10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d1 through d9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n1 through n5 denote refractive indices of the respective lens elements, the reference symbols ν
1 through ν
5 represent Abbe'"'"'s numbers of the respective lens elements, the reference symbol 1 designates distance as measured from an object to be observed or photographed to the front surface of the lens system, the reference symbol S denotes distance as measured from the rear surface of the lens system to the image, the reference symbol IH represents height of the image, the reference symbol 2.sub.ω
designates field angle, the reference symbol Σ
P denotes Petzval'"'"'s sum, the reference symbol NA represents numerical aperture, the reference symbol f represents total focal length of the entire lens system as a whole, and the reference symbol f234 designates total focal length of said second, third and fourth lens components as a whole.
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Specification