Ocular lens system

Claim 2

An ocular system composed of at least three lens elements for constituting, in order from the eye side, at least first and second lens units, at least one of said lens elements being made of resin, at least two of said lens elements being substantially cemented together and at least said lens element closest to the eye comprising glass.

Claim 3

The system according to claim 1, wherein said first lens unit has a positive focal length.

Claim 4

The system according to claim 2, wherein said second lens unit has a positive focal length.

Claim 6

The system according to claim 2, wherein said first lens unit is composed, in order from the eye side, of a positive first lens element and a negative meniscus second lens element, and said second lens unit is composed, in order from the eye side, of a positive third lens element and a negative fourth lens element.

Claim 7

The system according to claim 3, wherein said first lens unit is composed of a positive first lens element and said second lens unit is composed of a second lens element and a third lens element, in order from the eye side.

Claim 8

The system according to claim 6, wherein said second lens element has a positive focal length.

Claim 9

The system according to claim 7, wherein said third lens element has a positive focal length.

Claim 10

The system according to claim 7, wherein said third lens element has a negative focal length.

Claim 11

The system according to claim 1, wherein the lens element closest to an eye piece is made of glass.

Claim 12

The system according to claim 5, wherein said third and fourth lens elements are cemented together.

Claim 13

The system according to claim 6, wherein said second and third lens elements are cemented together.

Claim 14

The system according to claim 4, wherein the aspherical surface meets the following condition: ##EQU2## where X is an amount of deviation from an apex of the aspherical lens in an axial direction, Y is the amount of deviation from the apex in a vertical direction relative to the axial direction, C is the inverted number of the radius of curvature thereof, K is the conical constant, and A 4 , A 6 , . . . are the aspherical surface coefficients.

Claim 15

The system according to claim 5, further satisfying the following conditions: n<1.60, and (4) -4.0<f.sub.4 /f<-0.5 (6) where n is the average value of the refractive indexes of all the lens elements on d-line, f 4 is the focal length of the fourth lens element, and f is the focal length of the overall system.

Claim 16

The system according to claim 12, further satisfying the following conditions: |r.sub.4 /r.sub.n |<0.47 (1) 0.10<f/f.sub.II <0.65 (2) where r 4 is the radius of curvature of the bonded surface of the second lens unit, r n is the radius of curvature of the surface other than the bonded surface of the negative lens element of said second lens unit, f is the focal length of the overall system, and f II is the focal length of the second lens unit.

Claim 17

The system according to claim 5, further satisfying the following conditions: |r.sub.p /r.sub.n |<1.55 (3) n<1.60 (4) where r p is the radius of curvature other than the bonded surface of the positive lens element of the second lens unit, and r n is the average value of the refractive indexes of the three lens elements on d-line.

Claim 18

The system according to claim 5, further satisfying the following conditions: -1.70<r.sub.2 /r.sub.1 ≦0 (5) where r 1 and r 2 are the radii of curvature of the surfaces, on the eye side and the image side, of the first lens unit.

Claim 19

The system according to claim 1, satisfying the following conditions: ______________________________________ f = 1.0 F.sub.NO = 1:4.0 2ω = 56° Surface No. r d n v ______________________________________ 1 1.901 0.340 1.51633 64.1 2 -1.162 0.017 3 1.675 0.531 1.492 57.4 (resin) 4 -0.632 0.169 1.585 29.9 (resin) 5 -2.301 ______________________________________ aspherical third surface ______________________________________ K = 5.138 A.sub.4 = -2.17588 × 10.sup.-1 A.sub.6 = -3.22044 × 10.sup.-1 (1) |r.sub.4 /r.sub.n | = 0.275 (2) f/f.sub.II = 0.385 (3) |r.sub.p /r.sub.n | = 0.728 (4) - n = 1.531 (5) r.sub.2 /r.sub.1 = -0.611 ______________________________________ where f is the overall focal length, F NO is the F-number, 2ω is the viewing angle, r is the radius of curvature of each lens surface, d is the lens thickness or the interval between the adjacent lenses, n is the refractive index of each lens at d-line, v is the Abbe number, f II is the focal length of the second lens unit, n is the average value of the refractive indexes of all of the lens elements on d-line, K is the conical constant, A 4 and A 6 are the aspherical surface coefficients and r p and r n are the radii of curvature of surfaces other than the bonded surface of the positive lens element and the negative lens element, respectively, of the second lens unit.

Claim 20

The system according to claim 1, further satisfying the following conditions: ______________________________________ f = 1.0 F.sub.NO = 1:4.0 2ω = 56° Surface No. r d n v ______________________________________ 1 5.255 0.318 1.51633 64.1 2 -1.031 0.017 3 0.943 0.548 1.492 57.4 (resin) 4 -0.842 0.168 1.585 29.9 (resin) 5 8.573 ______________________________________ aspherical third surface ______________________________________ K = 0.414 A.sub.4 = 1.06217 × 10.sup.-1 A.sub.6 = 1.38306 × 10.sup.-1 (1) |r.sub.4 /r.sub.n | = 0.098 (2) f/f.sub.II = 0.380 (3) |r.sub.p /r.sub.n | = 0.110 (4) - n = 1.531 (5) r.sub.2 /r.sub.1 = -0.196 ______________________________________ where f is the overall focal length, F NO is the F-number, 2ω is the viewing angle, r is the radius of curvature of each lens surface, d is the lens thickness or the interval between the adjacent lenses, n is the refractive index of each lens at d-line, v is the Abbe number, f II is the focal length of the second lens unit, n is the average value of the refractive indexes of all of the lens elements on d-line, K is the conical constant, A 4 and A 6 are the aspherical surface coefficients and r p and r n are the radii of curvature of surfaces other than the bonded surface of the positive lens element and the negative lens element, respectively, of the second lens unit.

Claim 21

The system according to claim 1, further satisfying the following conditions: ______________________________________ f = 1.0 F.sub.NO = 1:4.0 2ω = 56° Surface No. r d n v ______________________________________ 1 1.523 0.382 1.51633 64.1 2 -1.433 0.017 3 1.011 0.604 1.492 57.4 (resin) 4 -0.752 0.126 1.585 29.9 (resin) 5 4.216 ______________________________________ aspherical third surface ______________________________________ K = 0.619 A.sub.4 = -1.05992 × 10.sup.-1 A.sub.6 = -3.44424 × 10.sup.-1 (1) |r.sub.4 /r.sub.n | = 0.178 (2) f/f.sub.II = 0.279 (3) |r.sub.p /r.sub.n | = 0.240 (4) - n = 1.531 (5) r.sub.2 /r.sub.1 = -0.941 ______________________________________ where f is the overall focal length, F NO is the F-number, 2ω is the viewing angle, r is the radius of curvature of each lens surface, d is the lens thickness or the interval between the adjacent lenses, n is the refractive index of each lens at d-line, v is the Abbe number, f II is the focal length of the second lens unit, n is the average value of the refractive indexes of all of the lens elements on d-line, K is the conical constant, A 4 and A 6 are the aspherical surface coefficients and r p and r n are the radii of curvature of surfaces other than the bonded surface of the positive lens element and the negative lens element, respectively, of the second lens unit.

Claim 22

The system according to claim 1, further satisfying the following conditions: ______________________________________ f = 1.0 F.sub.NO = 1:4.0 2ω = 56° Surface No. r d n v ______________________________________ 1 1.276 0.415 1.51633 64.1 2 -1.276 0.017 3 3.212 0.126 1.585 29.9 (resin) 4 0.730 0.573 1.492 57.4 (resin) 5 -1.340 ______________________________________ aspherical third surface ______________________________________ K = -16.561 A.sub.4 = -2.26060 × 10.sup.-1 A.sub.6 = -4.32136 × 10.sup.-1 (1) |r.sub.4 /r.sub.n | = 0.227 (2) f/f.sub.II = 0.410 (3) |r.sub.p /r.sub.n | = 0.417 (4) - n = 1.531 (5) r.sub.2 /r.sub.1 = -1.000 ______________________________________ wherein f is the overall focal length, F NO is the F-number, 2ω is the viewing angle, r is the radius of curvature of each lens surface, d is the lens thickness or the interval between the adjacent lenses, n is the refractive index of each lens at d-line, v is the Abbe number, f II is the focal length of the second lens unit, n is the average value of the refractive indexes of all of the lens elements on d-line, K is the conical constant, A 4 and A 6 are the aspherical surface coefficients and r p and r n are the radii of curvature of surfaces other than the bonded surface of the positive lens element and the negative lens element, respectively, of the second lens unit.

Claim 23

The system according to claim 1, further satisfying the following conditions: ______________________________________ f = 1.0 F.sub.NO = 1:4.0 2ω = 56° Surface No. r d n v ______________________________________ 1 1.427 0.422 1.492 57.4 2 -0.796 0.046 3 9.313 0.126 1.585 29.9 (resin) 4 0.632 0.560 1.492 57.4 (resin) 5 -1.446 ______________________________________ aspherical second surface ______________________________________ K = -0.064 A.sub.4 = 5.46435 × 10.sup.-1 A.sub.6 = 2.80405 × 10.sup.-1 (1) |r.sub.4 /r.sub.n | = 0.068 (2) f/f.sub.II = 0.265 (3) |r.sub.p /r.sub.n | = 0.155 (4) - n = 1.523 (5) r.sub.2 /r.sub.1 = -0.558 ______________________________________ where f is the overall focal length, F NO is the F-number, 2ω is the viewing angle, r is the radius of curvature of each lens surface, d is the lens thickness or the interval between the adjacent lenses, n is the refractive index of each lens at d-line, v is the Abbe number, f II is the focal length of the second lens unit, n is the average value of the refractive indexes of all of the lens elements on d-line, K is the conical constant, A 4 and A 6 are the aspherical surface coefficients and r p and r n are the radii of curvature of surfaces other than the bonded surface of the positive lens element and the negative lens element, respectively, of the second lens unit.

Claim 24

The system according to claim 1, further satisfying the following conditions: ______________________________________ f = 1.0 F.sub.NO = 1:4.0 2ω = 56° Surface No. r d n v ______________________________________ 1 1.276 0.415 1.51633 64.1 2 -1.276 0.017 3 3.212 0.126 1.585 29.9 (resin) 4 0.730 0.600 1.51633 64.1 5 -1.586 ______________________________________ aspherical third surface ______________________________________ K = -16.561 A.sub.4 = -2.26060 × 10.sup.-1 A.sub.6 = -4.32136 × 10.sup.-1 (1) |r.sub.4 /r.sub.n | = 0.227 (2) f/f.sub.II = 0.398 (3) |r.sub.p /r.sub.n | = 0.494 (4) - n = 1.539 (5) r.sub.2 /r.sub.1 = -1.000 ______________________________________ where f is the overall focal length, F NO is the F-number, 2ω is the viewing angle, r is the radius of curvature of each lens surface, d is the lens thickness or the interval between the adjacent lenses, n is the refractive index of each lens at d-line, v is the Abbe number, f II is the focal length of the second lens unit, n is the average value of the refractive indexes of all of the lens elements on d-line, K is the conical constant, A 4 and A 6 are the aspherical surface coefficients and r p and r n are the radii of curvature of surfaces other than the bonded surface of the positive lens element and the negative lens element, respectively, of the second lens unit.

Claim 25

The system according to claim 1, further satisfying the following conditions: ______________________________________ f = 1.0 F.sub.NO = 1:4.0 2ω = 56° Surface No. r d n v ______________________________________ 1 1.427 0.422 1.492 57.4 (resin) 2 -0.796 0.046 3 9.313 0.126 1.69895 30.1 4 0.800 0.560 1.51633 64.1 5 -1.208 ______________________________________ aspherical second surface ______________________________________ K = -0.070 A.sub.4 = -5.46435 × 10.sup.-1 A.sub.6 = -4.00000 × 10.sup.-1 (1) |r.sub.4 /r.sub.n | = 0.086 (2) f/f.sub.II = 0.297 (3) |r.sub.p /r.sub.n | = 0.130 (4) - n = 1.569 (5) r.sub.2 /r.sub.1 = -0.558 ______________________________________ where f is the overall focal length, F NO is the F-number, 2ω is the viewing angle, r is the radius of curvature of each lens surface, d is the lens thickness or the interval between the adjacent lenses, n is the refractive index of each lens at d-line, v is the Abbe number, f II is the focal length of the second lens unit, n is the average value of the refractive indexes of all of the lens elements on d-line, K is the conical constant, A 4 and A 6 are the aspherical surface coefficients and r p and r n are the radii of curvature of surfaces other than the bonded surface of the positive lens element and the negative lens element, respectively, of the second lens unit.

Claim 26

The system according to claim 1, further satisfying the following conditions: ______________________________________ f = 1.0 F.sub.NO = 1:4.0 2ω = 56° Surface No. r d n v ______________________________________ 1 1.427 0.422 1.492 57.4 (resin) 2 -0.796 0.046 3 9.313 0.126 1.69895 30.1 4 0.800 0.560 1.492 57.4 (resin) 5 -1.042 ______________________________________ aspherical second surface ______________________________________ K = -0.070 A.sub.4 = -5.46435 × 10.sup.-1 A.sub.6 = -6.00000 × 10.sup.-1 (1) |r.sub.4 /r.sub.n | = 0.086 (2) f/f.sub.II = 0.319 (3) |r.sub.p /r.sub.n | = 0.112 (4) - n = 1.561 (5) r.sub.2 /r.sub.1 = -0.558 ______________________________________ where f is the overall focal length, F NO is the F-number, 2ω is the viewing angle, r is the radius of curvature of each lens surface, d is the lens thickness or the interval between the adjacent lenses, n is the refractive index of each lens at d-line, v is the Abbe number, f II is the focal length of the second lens unit, n is the average value of the refractive indexes of all of the lens elements on d-line, K is the conical constant, A 4 and A 6 are the aspherical surface coefficients and r p and r n are the radii of curvature of surfaces other than the bonded surface of the positive lens element and the negative lens element, respectively, of the second lens unit.

Claim 27

The system according to claim 1, further satisfying the following conditions: ______________________________________ f = 1.0 F.sub.NO = 1:4.0 2ω = 56° Surface No. r d n v ______________________________________ 1 1.427 0.422 1.492 57.4 (resin) 2 -0.796 0.046 3 9.313 0.126 1.585 29.9 (resin) 4 0.632 0.560 1.51633 64.1 5 -1.851 ______________________________________ aspherical second surface ______________________________________ K = -0.064 A.sub.4 = -5.46435 × 10.sup.-1 A.sub.6 = -2.80405 × 10.sup.-1 (1) |r.sub.4 /r.sub.n | = 0.068 (2) f/f.sub.II = 0.236 (3) |r.sub.p /r.sub.n | = 0.199 (4) - n = 1.531 (5) r.sub.2 /r.sub.1 = -0.558 ______________________________________ where f is the overall focal length, F no is the F-number, 2ω is the viewing angle, r is the radius of curvature of each lens surface, d is the lens thickness or the interval between the adjacent lenses, n is the refractive index of each lens at d-line, v is the Abbe number, f II is the focal length of the second lens unit, n is the average value of the refractive indexes of all of the lens elements on d-line, K is the conical constant, A 4 and A 6 are the aspherical surface coefficients and r p and r n are the radii of curvature of surfaces other than the bonded surface of the positive lens element and the negative lens element, respectively, of the second lens unit.

Claim 28

The system according to claim 1, further satisfying the following conditions: ______________________________________ f = 1.0 F.sub.NO = 1:4.0 2ω = 56° Surface No. r d n v ______________________________________ 1 1.901 0.340 1.51633 64.1 2 -1.162 0.017 3 1.675 0.531 1.492 57.4 (resin) 4 0.680 0.169 1.69895 30.1 5 -1.636 ______________________________________ aspherical third surface ______________________________________ K = 5.138 A.sub.4 = -2.17588 × 10.sup.-1 A.sub.6 = -2.00000 × 10.sup.-1 (1) |r.sub.4 /r.sub.n | = 0.406 (2) f/f.sub.II = 0.403 (3) |r.sub.p /r.sub.n | = 0.977 (4) - n = 1.569 (5) r.sub.2 /r.sub.1 = -0.611 ______________________________________ where f is the overall focal length, F no is the F-number, 2ω is the viewing angle, r is the radius of curvature of each lens surface, d is the lens thickness or the interval between the adjacent lenses, n is the refractive index of each lens at d-line, v is the Abbe number, f II is the focal length of the second lens unit, n is the average value of the refractive indexes of all of the lens elements on d-line, K is the conical constant, A 4 and A 6 are the aspherical surface coefficients and r p and r n are the radii of curvature of surfaces other than the bonded surface of the positive lens element and the negative lens element, respectively, of the second lens unit.

Claim 29

An ocular system composed of at least three lens elements for constituting, in order from the eye side, at least first and second lens units, all of said lens elements being made of resin.

Claim 30

An ocular system composed of at least three lens elements for constituting, in order from the eye side, at least first and second lens units, all of said lens elements being made of resin.

Claim 31

The system according to claim 28, wherein said first lens unit has a positive focal length.

Claim 32

The system according to claim 28, wherein said second lens unit has a positive focal length.

Claim 34

The system according to claim 29, wherein said first lens unit is composed, in order from the eye side, of a positive first lens element and a negative meniscus second lens element, and said second lens unit is composed, in order from the eye side, of a positive third lens element and a negative fourth lens element.

Claim 35

The system according to claim 30, wherein said first lens unit is composed of a positive first lens element and said second lens unit is composed of a second lens element and a third lens element, in order from the eye side.

Claim 36

The system according to claim 31, wherein the aspherical surface meets the following condition: ##EQU3## where X is an amount of deviation from an apex of the aspherical lens in an axial direction, y is the amount of deviation from the apex in a vertical direction relative to the axial direction, C is the inverted number of the radius of curvature thereof, K is the conical constant, and A 4 , A 6 , . . . are the aspherical surface coefficients.

Claim 37

An ocular system composed, in order from the eye side, of a positive first lens element, a negative meniscus second lens element, a positive third lens element and a negative fourth lens element, at least third and fourth lens elements are made of resinous optical material.

Claim 38

An ocular system composed, in order from the eye side, of a positive first lens element, a negative meniscus second lens element, a positive third lens element and a negative fourth lens element, at least third and fourth lens elements are made of resinous optical material.

Claim 39

The system according to claim 35, wherein an aspherical surface is formed in said at least one of said lens elements made of resin.

Claim 40

The system according to claim 36, wherein the aspherical surface meets the following condition: ##EQU4## where X is an amount of deviation from an apex of the aspherical lens in an axial direction, y is the amount of deviation from the apex in a vertical direction relative to the axial direction, C is the inverted number of the radius of curvature thereof, K is the conical constant, and A 4 , A 6 , . . . are the aspherical surface coefficients.

Claim 41

The system according to claim 35, further satisfying the following conditions: ______________________________________ f = 1.0 F.sub.NO = 1:4.0 2ω = 56° Surface No. r d n v ______________________________________ 1 1.531 0.464 1.58913 61.2 2 -0.816 0.012 3 -0.795 0.084 1.585 29.9 (resin) 4 -1.539 0.017 5 1.085 0.411 1.492 57.4 (resin) 6 -1.444 0.027 7 -1.220 0.118 1.585 29.9 (resin) 8 8.585 ______________________________________ aspherical fifth surface ______________________________________ K = -0.487 A.sub.4 = -3.62572 × 10.sup.-2 (1) - n = 1.563 (2) f.sub.4 /f = -1.816 ______________________________________ where f is the overall focal length, F NO is the F-number, 2ω is the viewing angle, r is the radius of curvature of each lens surface, d is the lens thickness or the interval between the adjacent lenses, n is the refractive index of each lens at d-line, v is the Abbe number, n is the average value of the refractive indexes of all of the lens elements on d-line, K is the conical constant, A 4 is the aspherical surface coefficient and f 4 is the focal length of the fourth lens element.

Claim 42

The system according to claim 35, further satisfying the following conditions: ______________________________________ f = 1.0 F.sub.NO = 1:4.0 2ω = 56° Surface No. r d n v ______________________________________ 1 1.239 0.528 1.51633 64.1 2 -0.759 0.084 1.64769 33.8 3 -1.328 0.017 4 -0.969 0.460 1.492 57.4 (resin) 5 -1.286 0.034 6 -1.079 0.121 1.585 29.9 (resin) 7 4.744 ______________________________________ aspherical third surface ______________________________________ K = -0.946 A.sub.4 = 2.30838 × 10.sup.-2 (1) - n = 1.560 (2) f.sub.4 /f = -1.490 ______________________________________ where f is the overall focal length, F NO is the F-number, 2ω is the viewing angle, r is the radius of curvature of each lens surface, d is the lens thickness or the interval between the adjacent lenses, n is the refractive index of each lens at d-line, and v is the Abbe number, n is the average value of the refractive indexes of all of the lens elements on d-line, K is the conical constant, A 4 is the aspherical surface coefficient and f 4 is the focal length of the fourth lens element.

Claim 43

The system according to claim 35, further satisfying the following conditions: ______________________________________ f = 1.0 F.sub.NO = 1:4.0 2ω = 56° Surface No. r d n v ______________________________________ 1 1.316 0.494 1.492 57.4 (resin) 2 -0.770 0.015 3 -0.744 0.084 1.585 29.9 (resin) 4 -1.205 0.017 5 1.065 0.443 1.492 57.4 (resin) 6 -1.108 0.026 7 -0.977 0.118 1.585 29.9 (resin) 8 -37.946 ______________________________________ aspherical first surface ______________________________________ K = 0.215 A.sub.4 = 3.72173 × 10.sup.-2 ______________________________________ aspherical fifth surface ______________________________________ K = -0.765 A.sub.4 = -8.73876 × 10.sup.-2 (1) - n = 1.539 (2) f.sub.4 /f = -1.714 ______________________________________ where f is the overall focal length, F NO is the F-number, 2ω is the viewing angle, r is the radius of curvature of each lens surface, d is the lens thickness or the interval between the adjacent lenses, n is the refractive index of each lens at d-line, and v is the Abbe number, n is the average value of the refractive indexes of all of the lens elements on d-line, K is the conical constant, A 4 is the aspherical surface coefficient, and f 4 is the focal length of the fourth lens element.

Claim 44

The system according to claim 35, further satisfying the following conditions: ______________________________________ f = 1.0 F.sub.NO = 1:4.0 2ω = 56° Surface No. r d n v ______________________________________ 1 1.671 0.642 1.51633 64.1 2 -0.675 0.084 1.64769 33.8 3 -1.049 0.017 4 0.888 0.574 1.492 57.4 (resin) 5 -1.945 0.188 1.585 29.9 (resin) 6 -1.889 ______________________________________ aspherical fourth surface ______________________________________ K = -1.015 A.sub.4 = 9.16712 × 10.sup.-2 (1) - n = 1.560 (2) f.sub.4 /f = -1.059 ______________________________________ where f is the overall focal length, F NO is the F-number, 2ω is the viewing angle, r is the radius of curvature of each lens surface, d is the lens thickness or the interval between the adjacent lenses, n is the refractive index of each lens at d-line, v is the Abbe number, n is the average value of the refractive indexes of all of the lens elements on d-line, K is the conical constant, A 4 is the aspherical surface coefficient and f 4 is the focal length of the fourth lens element.

Claim 45

The system according to claim 35, further satisfying the following conditions: ______________________________________ f = 1.0 F.sub.NO = 1:4.0 2ω = 56° Surface No. r d n v ______________________________________ 1 1.239 0.500 1.492 57.4 (resin) 2 -0.759 0.084 1.64769 33.8 3 -1.328 0.017 4 0.969 0.460 1.492 57.4 (resin) 5 -1.286 0.034 6 -1.079 1.021 1.585 29.9 (resin) 7 41.319 ______________________________________ aspherical fourth surface ______________________________________ K = -0.946 A.sub.4 = 2.30838 × 10.sup.-2 (1) - n = 1.554 (2) f.sub.4 /f = -1.795 ______________________________________ where f is the overall focal length, F NO is the F-number, 2ω is the viewing angle, r is the radius of curvature of each lens surface, d is the lens thickness or the interval between the adjacent lenses, n is the refractive index of each lens at d-line, v is the Abbe number, n is the average value of the refractive indexes of all of the lens elements on d-line, K is the conical constant, A 4 is the aspherical surface coefficient and f 4 is the focal length of the fourth lens element.