Objective lens system for endoscopes

Claim 2

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 f 234 designates total focal length of said second, third and fourth lens components as a whole, the reference symbols r 2 , r 5 and r 7 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 n 1 through n 5 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.

Claim 3

An objective lens system for endoscopes according to claim 1 wherein said aperture stop is arranged in the vicinity of the object side focal point of said rear lens group consisting of said second, third and fourth lens components.

Claim 4

An objective lens system for endoscopes according to claim 1 having the following numerical data: ______________________________________ r.sub.1 = 40.340 d.sub.1 = 0.509 n.sub.1 = 1.58913 ν.sub.1 = 60.97 r.sub.2 = 0.844 d.sub.2 = 1.253 r.sub.3 = ∞ d.sub.3 = 0.372 r.sub.4 = -35.462 d.sub.4 = 1.067 n.sub.2 = 1.69680 ν.sub.2 = 55.52 r.sub.5 = -2.318 d.sub.5 = 0.124 r.sub.6 = 9.484 d.sub.6 = 1.129 n.sub.3 =1.51728 ν.sub.3 = 69.56 r.sub.7 = -2.955 d.sub.7 = 0.124 r.sub.8 = 2.782 d.sub.8 = 1.948 n.sub.4 = 1.61800 ν.sub.4 = 63.38 r.sub.9 = -1.608 d.sub.9 = 0.434 n.sub.5 = 1.84666 ν.sub.5 = 23.90 r.sub.10 = - 49.305 f = 1.0, 1 = 15.0, S = 0.81 IH = 0.881 2ω = 115.84°, ΣP = -0.014 NA = 0.0129, f.sub.234 /f = 1.614 ##STR16## ______________________________________ wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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, reference symbols IH represents height of the image, the reference symbol 2ω designates field angle, the reference symbol ΣP denotes Petzval's sum and the reference symbol NA represents numerical aperture.

Claim 5

An objective lens system for endoscopes according to claim 1 having the following numerical data: ______________________________________ r.sub.1 = 20.6504 d.sub.1 = 0.5001 n.sub.1 = 1.58913 ν.sub.1 = 60.97 r.sub.2 = 0.8479 d.sub.2 = 1.2476 r.sub.3 = ∞ d.sub.3 = 0.3770 r.sub.4 = -63.1598 d.sub.4 = 1.0635 n.sub.2 = 1.69680 ν.sub.2 = 55.52 r.sub.5 = -2.4379 d.sub.5 = 0.1251 r.sub.6 = 7.2310 d.sub.6 = 1.1253 n.sub.3 = 1.51728 ν.sub.3 = 69.56 r.sub.7 = -3.0381 d.sub.7 = 0.1255 r.sub.8 = 2.6453 d.sub.8 = 1.8743 n.sub.4 = 1.61800 ν.sub.4 = 63.38 r.sub.9 = -1.6289 d.sub.9 = 0.4375 n.sub.5 = 1.84666 ν.sub.5 = 23.90 r.sub.10 = -812.0951 f = 1.0, 1 = 15.0, S = 0.773 IH = 0.881, 2ω = 115.57°, ΣP = 0 NA = 0.0129, f.sub.234 /f = 1.587 ##STR17## ______________________________________ wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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 ΣP denotes Petzval's sum and the reference symbol NA represents numerical aperture.

Claim 6

An objective lens system for endoscopes according to claim 1 having the following numerical data: ______________________________________ r.sub.1 = 21.3790 d.sub.1 = 0.5062 n.sub.1 = 1.58913 ν.sub.1 = 60.97 r.sub.2 = 0.8417 d.sub.2 = 1.2469 r.sub.3 = ∞ d.sub.3 = 0.3704 r.sub.4 = -35.9354 d.sub.4 = 1.0617 n.sub.2 = 1.69680 ν.sub.2 = 55.52 r.sub.5 = -2.2956 d.sub.5 = 0.1246 r.sub.6 = 8.7810 d.sub.6 = 1.1235 n.sub.3 = 1.51728 ν.sub.3 = 69.56 r.sub.7 = -3.0240 d.sub.7 = 0.1235 r.sub.8 = 2.6730 d.sub.8 = 1.8765 n.sub.4 = 1.61800 ν.sub.4 = 63.38 r.sub.9 = -1.6290 d.sub.9 = 0.4321 n.sub.5 = 1.84666 ν.sub.5 = 23.90 r.sub.10 = -206.3722 f = 1.0, 1 = 15.0, S = 0.794 IH = 0.881, 2ω = 114.86°, ΣP = -0.006 NA = 0.0129, f.sub.234 /f = 1.589 ##STR18## ______________________________________ wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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 ΣP denotes Petzval's sum and the reference symbol NA represents numerical aperture.

Claim 7

An objective lens system for endoscopes according to claim 1 having the following numerical data: ______________________________________ r.sub.1 = 17.6741 d.sub.1 = 0.4938 n.sub.1 = 1.58913 ν.sub.1 = 60.97 r.sub.2 = 0.8373 d.sub.2 = 0.9877 r.sub.3 = ∞ d.sub.3 = 0.6173 r.sub.4 = -36.3478 d.sub.4 = 1.0494 n.sub.2 = 1.69680 ν.sub.2 = 55.52 r.sub.5 = -2.4411 d.sub.5 = 0.1246 r.sub.6 = 6.5303 d.sub.6 = 1.0864 n.sub.3 = 1.48749 ν.sub.3 = 70.15 r.sub.7 = -2.8037 d.sub.7 = 0.1235 r.sub.8 = 2.5290 d.sub.8 = 1.7284 n.sub.4 = 1.61800 ν.sub.4 = 63.38 r.sub.9 = -1.5909 d.sub.9 = 0.4321 n.sub.5 = 1.84666 ν.sub.5 = 23.90 r.sub.10 = 89.7642 f = 1.0, 1 = 15.0, S = 0.863 IH = 0.881, 2ω = 115.53°, ΣP = 0 NA = 0.0129, f.sub.234 /f = 1.574 ##STR19## ______________________________________ wherein reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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 ΣP denotes Petzval's sum and the reference symbol NA represents numerical aperture.

Claim 8

An objective lens system for endoscopes according to claim 1 having the following numerical data: ______________________________________ r.sub.1 = 20.3968 d.sub.1 = 0.4938 n.sub.1 = 1.58913 ν.sub.1 = 60.97 r.sub.2 = 0.8374 d.sub.2 = 0.9877 r.sub.3 = ∞ d.sub.3 = 0.6173 r.sub.4 = -62.3951 d.sub.4 = 1.0494 n.sub.2 = 1.6968 ν.sub.2 = 55.52 r.sub.5 = -2.4077 d.sub.5 = 0.1235 r.sub.6 = 7.1414 d.sub.6 = 1.1110 n.sub.3 = 1.51728 ν.sub.3 = 69.56 r.sub.7 = -3.0005 d.sub.7 = 0.1236 r.sub.8 = 2.6126 d.sub.8 = 1.7284 n.sub.4 = 1.61800 ν.sub.4 = 63.38 r.sub.9 = -1.6088 d.sub.9 = 0.4321 n.sub.5 = 1.84666 ν.sub.5 = 23.90 r.sub.10 = - 796.822 f = 1, 1 = 15.0, S = 0.863 IH = 0.881, 2ω = 115.71°, ΣP = 0 NA = 0.013, f.sub.234 /f = 1.584 ##STR20## ______________________________________ wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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 ΣP denotes Petzval's sum and the reference symbol NA represents numerical aperture.

Claim 9

An objective lens system for endoscopes according to claim 1 having the following numerical data: ______________________________________ r.sup.1 = 46.5568 d.sub.1 = 0.5043 n.sub.1 = 1.58913 ν.sub.1 = 60.97 r.sub.2 = 0.8358 d.sub.2 = 1.2423 r.sub.3 = ∞ d.sub.3 = 0.3690 r.sub.4 = -39.4208 d.sub.4 = 1.0578 n.sub.2 = 1.6968 ν.sub.2 = 55.52 r.sub.5 = -2.2932 d.sub.5 = 0.1230 r.sub.6 = 8.9076 d.sub.6 = 1.1193 n.sub.3 = 1.5728 ν.sub.3 = 69.56 r.sub.7 = -2.9702 d.sub.7 = 0.1230 r.sub.8 = 2.7349 d.sub.8 = 1.8696 n.sub.4 = 1.61800 ν.sub.4 = 63.38 r.sub.9 = -1.5664 d.sub.9 = 0.4305 n.sub.5 = 1.84666 ν.sub.5 = 23.90 r.sub.10 = -363.0739 f = 1.0, l = 15.0, S = 0.838 IH = 0.881, 2ω = 115.646°, ΣP = -0.022 NA = 0.0129, f.sub.234 /f = 1.53 ##STR21## ______________________________________ wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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 sybmol IH represents height of the image, the reference symbol 2ω designates field angle, the reference symbol ΣP denotes Petzval's sum and the reference symbol NA represents numerical aperture.

Claim 10

An objective lens system for endoscopes according to claim 1 having the following numerical data: ______________________________________ r.sub.1 = 75.582 d.sub.1 = 0.523 n.sub.1 = 1.58913 ν.sub.1 = 60.97 r.sub.2 = 0.872 d.sub.2 = 1.264 r.sub.3 = ∞ d.sub.3 = 0.376 r.sub.4 = -31.949 d.sub.4 = 1.076 n.sub.2 = 1.69680 ν.sub.2 = 55.52 r.sub.5 = -2.309 d.sub.5 = 0.125 r.sub.6 = 10.102 d.sub.6 = 1.139 n.sub.3 = 1.51728 ν.sub.3 = 69.56 r.sub.7 = -2.963 d.sub.7 = 0.125 r.sub.8 = 2.737 d.sub.8 = 1.965 n.sub.4 = 1.6180 ν.sub.4 = 63.38 r.sub.9 = -1.602 d.sub.9 = 0.439 n.sub.5 = 1.84666 ν.sub.5 = 23.90 r.sub.10 = - 72.703 f = 1.0, l = 15.0, S = 0.78 IH = 0.888. 2ω = 117.85°, ΣP = -0.009 NA = 0.0132, f.sub.234 /f = 1.563 ##STR22## ______________________________________ wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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 ΣP denotes Petzval's sum and the reference symbol NA represents numerical aperture.

Claim 11

An objective lens system for endoscopes according to claim 1 having the following numerical data: ______________________________________ r.sub.1 = 76.346 d.sub.1 = 0.5277 n.sub.1 = 1.58913 ν.sub.1 = 60.97 r.sub.2 = 0.880 d.sub.2 = 1.2771 r.sub.3 = ∞ d.sub.3 = 0.38 r.sub.4 = -31.030 d.sub.4 = 1.0872 n.sub.2 = 1.670 ν.sub.2 = 57.33 r.sub.5 = -2.242 d.sub.5 = 0.1010 r.sub.6 = 10.204 d.sub.6 = 1.1505 n.sub.3 = 1.51728 ν.sub.3 = 69.56 r.sub.7 = -2.993 d.sub.7 = 0.1010 r.sub.8 = 2.764 d.sub.8 = 2.0202 n.sub.4 = 1.618 ν.sub.4 = 63.38 r.sub.9 = -1.618 d.sub.9 = 0.4433 n.sub.5 = 1.84666 ν.sub.5 = 23.90 r.sub.10 = -73.4376 f = 1.0, l = 15.0, S = 0.762 IH = 0.899, 2ω = 120.19°, ΣP = -0.006 NA = 0.013, f.sub.234 /f = 1.612 ##STR23## ______________________________________ wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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 ΣP denotes Petzval's sum and the reference symbol NA represents numerical aperture.

Claim 12

An objective lens system for endoscopes according to claim 1 having the following numerical data: ______________________________________ r.sub.1 = 75.582 d.sub.1 = 0.523 n.sub.1 = 1.58913 ν.sub.1 = 60.97 r.sub.2 = 0.872 d.sub.2 = 1.264 r.sub.3 = ∞ d.sub.3 = 0.376 r.sub.4 = -31.949 d.sub.4 = 1.076 n.sub.2 = 1.6968 ν.sub.2 = 55.52 r.sub.5 = -2.309 d.sub.5 = 0.125 r.sub.6 = 10.102 d.sub.6 = 1.139 n.sub.3 = 1.51728 ν.sub.3 = 69.56 r.sub.7 = -2.963 d.sub.7 = 0.125 r.sub.8 = 3.074 d.sub.8 = 1.965 n.sub.4 = 1.69249 ν.sub.4 = 58.56 r.sub.9 = -1.602 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 = 0.853 IH = 0.89, 2ω = 117.6°, ΣP = -0.005 NA = 0.0129, f.sub.234 /f = 1.583 ##STR24## ______________________________________ wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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 ΣP denotes Petzval's sum and the reference symbol NA represents numerical aperture.

Claim 13

An objective lens system for endoscopes according to claim 1 having the following numerical data: ______________________________________ r.sub.1 = 39.261 d.sub.1 = 0.45 n.sub.1 = 1.58913 ν.sub.1 = 60.97 r.sub.2 = 0.834 d.sub.2 = 1.28 r.sub.3 = ∞ d.sub.3 = 0.38 r.sub.4 = -33.554 d.sub.4 = 1.05 n.sub.2 = 1.6968 ν.sub.2 = 55.52 r.sub.5 = -2.325 d.sub.5 = 0.1 r.sub.6 = 10.771 d.sub.6 = 1.06 n.sub.3 = 1.51728 ν.sub.3 = 69.56 r.sub.7 = -2.962 d.sub.7 = 0.1 r.sub.8 = 2.907 d.sub.8 = 1.85 n.sub.4 = 1.6180 ν.sub.4 = 63.38 r.sub.9 = -1.659 d.sub.9 = 0.44 n.sub.5 = 1.84666 ν.sub.5 = 23.90 r.sub.10 = - 22.0281 f = 1.0, l = 15.0, S = 0.986 IH = 0.9, 2ω = 118°, ΣP = -0.018 NA = 0.0133, f.sub.234 /f = 1.651 ##STR25## ______________________________________ wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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 ΣP denotes Petzval's sum and the reference symbol NA represents numerical aperture.

Claim 14

An objective lens system for endoscopes according to claim 1 having the following numerical data: ______________________________________ r.sub.1 = 53.309 d.sub.1 = 0.444 n.sub.1 = 1.58913 ν.sub.1 = 60.97 r.sub.2 = 0.833 d.sub.2 = 1.262 r.sub.3 = ∞ d.sub.3 = 0.375 r.sub.4 = -31.892 d.sub.4 = 1.036 n.sub.2 = 1.6968 ν.sub.2 = 55.52 r.sub.5 = -2.305 d.sub.5 = 0.099 r.sub.6 = 10.489 d.sub.6 = 1.045 n.sub.3 = 1.51728 ν.sub.3 = 69.56 r.sub.7 = -2.934 d.sub.7 = 0.099 r.sub.8 = 2.852 d.sub.8 = 1.825 n.sub.4 = 1.6180 ν.sub.4 = 63.38 r.sub.9 = -1.638 d.sub.9 = 0.434 n.sub.5 = 1.84666 ν.sub.5 = 23.90 r.sub.10 = -22.031 f = 1.0, 1 = 15.0, S = 0.974 IH = 0.89, 2ω = 118.0°, ΣP = -0.016 NA = 0.0129, f.sub.234 /f = 1.630 ##STR26## ______________________________________ wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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 ΣP denotes Petzval's sum and the reference symbol NA represents numerical aperture.

Claim 15

An objective lens system for endoscopes according to claim 1 having the following numerical data: ______________________________________ r.sub.1 = 87.350 d.sub.1 = 0.523 n.sub.1 = 1.58913 ν.sub.1 = 60.97 r.sub.2 = 0.871 d.sub.2 = 1.264 r.sub.3 = ∞ d.sub.3 = 0.376 r.sub.4 = -34.593 d.sub.4 = 1.076 n.sub.2 = 1.6968 ν.sub.2 = 55.52 r.sub.5 = -2.281 d.sub.5 = 0.125 r.sub.6 = 11.081 d.sub.6 = 1.080 n.sub.3 = 1.48749 ν.sub.3 = 70.15 r.sub.7 = -2.839 d.sub.7 = 0.120 r.sub.8 = 2.693 d.sub.8 = 1.965 n.sub.4 = 1.6180 ν.sub.4 = 63.38 r.sub.9 = -1.604 d.sub.9 = 0.439 n.sub.5 = 1.84666 ν.sub.5 = 23.90 r.sub.10 = -62.149 f = 1.0, 1 = 15.0, S = 0.794 IH = 0.89, 2ω = 118.58°, ΣP = -0.007 NA = 0.0127, f.sub.234 /f = 1.610 ##STR27## ______________________________________ wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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 ΣP denotes Petzval's sum and the reference symbol NA represents numerical aperture.

Claim 16

An objective lens system for endoscopes according to claim 1 having the following numerical data: ______________________________________ r.sub.1 = 42.483 d.sub.1 = 0.423 n.sub.1 = 1.51633 ν.sub.1 = 64.15 r.sub.2 = 0.809 d.sub.2 = 1.259 r.sub.3 = ∞ d.sub.3 = 0.374 r.sub.4 = -42.497 d.sub.4 = 1.032 n.sub.2 = 1.69680 ν.sub.2 = 55.52 r.sub.5 = -2.358 d.sub.5 = 0.098 r.sub.6 = 7.206 d.sub.6 = 1.032 n.sub.3 = 1.51728 ν.sub.3 = 69.56 r.sub.7 = -3.096 d.sub.7 = 0.098 r.sub.8 = 2.615 d.sub.8 = 1.770 n.sub.4 = 1.61800 ν.sub.4 = 63.38 r.sub.9 = -1.658 d.sub.9 = 0.433 n.sub.5 = 1.84666 ν.sub.5 = 23.90 r.sub.10 = -76.590 f = 1.0, 1 = 15.0, S = 0.794 IH = 0.885, 2ω = 118°, ΣP = 0.015 NA = 0.0129, f.sub.234 /f = 1.562 ##STR28## ______________________________________ wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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 ΣP denotes Petzval's sum and the reference symbol NA represents numerical aperture.

Claim 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: ______________________________________ 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°, ΣP = 0 NA = 0.0129, f.sub.234 /f = 1.591 ##STR29## ______________________________________ wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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 ΣP 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 f 234 designates total focal length of said second, third and fourth lens components as a whole.

Claim 18

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: ______________________________________ 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°, ΣP = 0 NA = 0.0129, f.sub.234 /f = 1.591 ##STR29## ______________________________________ wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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 ΣP 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 f 234 designates total focal length of said second, third and fourth lens components as a whole.

Claim 19

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: ______________________________________ 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°, ΣP = -0.036 NA = 0.0128, f.sub.234 /f = 1.666 ##STR30## ______________________________________ wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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 ΣP 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 f 234 designates total focal length of said second, third and fourth lens components as a whole.

Claim 20

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: ______________________________________ 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°, ΣP = -0.036 NA = 0.0128, f.sub.234 /f = 1.666 ##STR30## ______________________________________ wherein the reference symbols r 1 through r 10 represent radii of curvature on the surfaces of the respective lens elements including said stop, the reference symbols d 1 through d 9 designate thicknesses of the respective lens elements and airspaces reserved therebetween, the reference symbols n 1 through n 5 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 ΣP 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 f 234 designates total focal length of said second, third and fourth lens components as a whole.