Thin type photographic lens system

Claim 2

A photographic objective lens system consisting of: positive meniscus lens means of forward convexity, bi-concave lens means arranged toward the image end of said positive meniscus means, biconvex lens means arranged toward the image end of said bi-concave lens means, and negative meniscus lens means of forward concavity arranged toward the image end of said bi-convex lens means, said positive meniscus lens means, said bi-concave lens means, and said bi-convex means being arranged for movement along a common optical axis for effecting focusing of said photographic lens system, said lens means having surfaces satisfying the following: 2.

Claim 3

2<r 2 /r 1 <3.8 where r 1 is the radius of curvature of the front surface of the positive meniscus lens and r 2 is the radius of curvature of the rear surface of the positive mensicus lens; said negative meniscus lens means having at least one aspheric surface, and wherein 0.6<|f A |/f<1.0, f A <0 where f is the focal length of the entire system and f A is the focal length of the air lens formed between the positive meniscus lens means and the bi-concave lens means, said lens means satisfying the following conditions:

Claim 4

2<r 2 /r 1 <3.8 where r 1 is the radius of curvature of the front surface of the positive meniscus lens and r 2 is the radius of curvature of the rear surface of the positive mensicus lens; said negative meniscus lens means having at least one aspheric surface, and wherein 0.6<|f A |/f<1.0, f A <0 where f is the focal length of the entire system and f A is the focal length of the air lens formed between the positive meniscus lens means and the bi-concave lens means, said lens means satisfying the following conditions:

Claim 5

6<r 5 /r 4 <1.2 where r 4 is the radius of curvature of the rear surface of the bi-concave lens means and r 5 is the radius of curvature of the front

Claim 6

6<r 5 /r 4 <1.2 where r 4 is the radius of curvature of the rear surface of the bi-concave lens means and r 5 is the radius of curvature of the front

Claim 7

surface of the bi-concave lens means. 2. A photographic objective lens system comprising: positive meniscus lens means of forward convexity, bi-concave lens means arranged toward the image end of said positive meniscus means, biconvex lens means arranged toward the image end of said bi-concave lens means, and negative meniscus lens means of forward concavity arranged toward the image end of said bi-convex lens means, said positive meniscus lens means, said bi-concave lens means, and said bi-convex means being arranged for movement along a common optical axis for effecting focusing of said photographic lens system, said lens means having surfaces satisfying the following:

Claim 8

surface of the bi-concave lens means. 2. A photographic objective lens system comprising: positive meniscus lens means of forward convexity, bi-concave lens means arranged toward the image end of said positive meniscus means, biconvex lens means arranged toward the image end of said bi-concave lens means, and negative meniscus lens means of forward concavity arranged toward the image end of said bi-convex lens means, said positive meniscus lens means, said bi-concave lens means, and said bi-convex means being arranged for movement along a common optical axis for effecting focusing of said photographic lens system, said lens means having surfaces satisfying the following:

Claim 9

2<r 2 /r 1 <3.8 where r 1 is the radius of curvature of the front surface of the positive meniscus lens and r 2 is the radius of curvature of the rear surface of the positive mensicus lens, said negative meniscus lens means having at least one aspheric surface, and wherein 0.6<|f A |/f<1.0, f A <0 where f is the focal length of the entire system and f A is the focal length of the air lens formed between the positive meniscus lens means and the bi-concave lens means, said lens means satisfying the following conditions: 0.6<r 5 /r 4 <1.2 where r 4 is the radius of curvature of the rear surface of the bi-concave lens means and r 5 is the radius of curvature of the front surface of the bi-concave lens means, said lens means defining an axial direction and a perpendicular direction transverse to the axial direction, and taking the axial direction as an X-axis with the orgin at the vertex of the front surface of said negative meniscus lens means and the perpendicular direction as a Y-axis and using an equation X=F(Y) in expressing this symmetric front surface with respect to the optical axis, the following conditions being satisfied: × 1 - <Δ X(0.7R)/f<2×10 -3 1×10 -4 <ΔX(0.5R)/f<5×10 -4 where ΔX(0.7R) and ΔX(0.5R) represent the values which the amount of deviation of the aspheric surface from the paraxial surface (the radius of curvature R) as defined below takes when Y=0.7R and Y=0.5R respectively, and f is the focal length of the entire system, and wherein ##EQU3##

Claim 10

2<r 2 /r 1 <3.8 where r 1 is the radius of curvature of the front surface of the positive meniscus lens and r 2 is the radius of curvature of the rear surface of the positive mensicus lens, said negative meniscus lens means having at least one aspheric surface, and wherein 0.6<|f A |/f<1.0, f A <0 where f is the focal length of the entire system and f A is the focal length of the air lens formed between the positive meniscus lens means and the bi-concave lens means, said lens means satisfying the following conditions: 0.6<r 5 /r 4 <1.2 where r 4 is the radius of curvature of the rear surface of the bi-concave lens means and r 5 is the radius of curvature of the front surface of the bi-concave lens means, said lens means defining an axial direction and a perpendicular direction transverse to the axial direction, and taking the axial direction as an X-axis with the orgin at the vertex of the front surface of said negative meniscus lens means and the perpendicular direction as a Y-axis and using an equation X=F(Y) in expressing this symmetric front surface with respect to the optical axis, the following conditions being satisfied: × 1 - <Δ X(0.7R)/f<2×10 -3 1×10 -4 <ΔX(0.5R)/f<5×10 -4 where ΔX(0.7R) and ΔX(0.5R) represent the values which the amount of deviation of the aspheric surface from the paraxial surface (the radius of curvature R) as defined below takes when Y=0.7R and Y=0.5R respectively, and f is the focal length of the entire system, and wherein ##EQU3##

Claim 11

A photographic objective lens system comprising: positive meniscus lens means of forward convexity, bi-concave lens means arranged toward the image end of said positive meniscus means, biconvex lens means arranged toward the image end of said bi-concave lens means, and negative meniscus lens means of forward concavity arranged toward the image end of said bi-convex lens means, said positive meniscus lens means, said bi-concave lens means, and said bi-convex means being arranged for movement along a common optical axis for effecting focusing of said photographic lens system, said lens means having surfaces satisfying the following: 2.2<r 2 /r 1 <3.8 where r 1 is the radius of curvature of the front surface of the positive meniscus lens and r 2 is the radius of curvature of the rear surface of the positive mensicus lens, said lens means defining an axial direction and a perpendicular direction transverse to the axial direction, and taking the axial direction to an X-axis with the origin at the vertex of the front surface of said negative meniscus lens means and the perpendicular direction as a Y-axis and using an equation X=F(Y) in expressing this symmetric front surface with respect to the optical axis, the following conditions being satisfied: 1×10 -3 <ΔX(0.7R)/f<2×10 -3 1×10 -4 <ΔX(0.5R)/f<5×10 -4 where ΔX(0.7R) and ΔX(0.5R) represent the values which the amount of deviation of the aspheric surface from the paraxial surface (the radius of curvature R) as described below takes when Y=0.7R and Y=0.5R respectively, and f is the focal length of the entire system, and wherein ##EQU4##

Claim 12

A photographic objective lens system comprising: positive meniscus lens means of forward convexity, bi-concave lens means arranged toward the image end of said positive meniscus means, biconvex lens means arranged toward the image end of said bi-concave lens means, and negative meniscus lens means of forward concavity arranged toward the image end of said bi-convex lens means, said positive meniscus lens means, said bi-concave lens means, and said bi-convex means being arranged for movement along a common optical axis for effecting focusing of said photographic lens system, said lens means having surfaces satisfying the following: 2.2<r 2 /r 1 <3.8 where r 1 is the radius of curvature of the front surface of the positive meniscus lens and r 2 is the radius of curvature of the rear surface of the positive mensicus lens, said lens means defining an axial direction and a perpendicular direction transverse to the axial direction, and taking the axial direction to an X-axis with the origin at the vertex of the front surface of said negative meniscus lens means and the perpendicular direction as a Y-axis and using an equation X=F(Y) in expressing this symmetric front surface with respect to the optical axis, the following conditions being satisfied: 1×10 -3 <ΔX(0.7R)/f<2×10 -3 1×10 -4 <ΔX(0.5R)/f<5×10 -4 where ΔX(0.7R) and ΔX(0.5R) represent the values which the amount of deviation of the aspheric surface from the paraxial surface (the radius of curvature R) as described below takes when Y=0.7R and Y=0.5R respectively, and f is the focal length of the entire system, and wherein ##EQU4##

Claim 13

A photographic objective lens system comprising: positive meniscus lens means of forward convexity, bi-concave lens means arranged on the image side of said positive meniscus lens means, bi-convex lens means arranged on the image side of said bi-concave lens means, and negative meniscus lens means of forward concavity arranged on the image side of said bi-convex lens means, said positive meniscus lens means, said bi-concave lens means and said bi-convex lens means being arranged to be moved along a common optical axis for effecting focusing of said photographic lens system, the front surface of said negative meniscus lens means is aspheric, taking the axial direction as X-axis with the original point at the vertex of the front surface of said negative meniscus lens means and the perpendicular direction as Y-axis and using an equation X=F(Y) in expressing the symmetric front surface with respect to the optical axis, the following conditions are satisfied: 1×10 -3 <ΔX(0.7R)/f2×10 -3 1×10 -4 <ΔX(0.5R)/f5×10 -4 where ΔX(0.7R) and ΔX(0.5R) represent the values which the amount of deviation of the aspheric surface from the paraxial surface (the radius of curvature R) as defined below takes when Y=0.7R and Y=0.5R respectively, and f is the focal length of the entire system ##EQU5##

Claim 14

A photographic objective lens system comprising: positive meniscus lens means of forward convexity, bi-concave lens means arranged on the image side of said positive meniscus lens means, bi-convex lens means arranged on the image side of said bi-concave lens means, and negative meniscus lens means of forward concavity arranged on the image side of said bi-convex lens means, said positive meniscus lens means, said bi-concave lens means and said bi-convex lens means being arranged to be moved along a common optical axis for effecting focusing of said photographic lens system, the front surface of said negative meniscus lens means is aspheric, taking the axial direction as X-axis with the original point at the vertex of the front surface of said negative meniscus lens means and the perpendicular direction as Y-axis and using an equation X=F(Y) in expressing the symmetric front surface with respect to the optical axis, the following conditions are satisfied: 1×10 -3 <ΔX(0.7R)/f2×10 -3 1×10 -4 <ΔX(0.5R)/f5×10 -4 where ΔX(0.7R) and ΔX(0.5R) represent the values which the amount of deviation of the aspheric surface from the paraxial surface (the radius of curvature R) as defined below takes when Y=0.7R and Y=0.5R respectively, and f is the focal length of the entire system ##EQU5##

Claim 15

A photographic lens system according to claim 4, satisfying the following conditions: ##EQU6## where f is the focal length of the entire system, fA is the focal length of the air lens formed between said positive meniscus lens means and said bi-concave lens means, r 1 is the radius of curvature on the front surface of said positive meniscus lens means, r 2 is the radius of curvature of the rear surface of said positive meniscus lens means, r 4 is the radius of curvature of the rear surface of said bi-concave lens means, and r 5 is the radius of curvature of the front surface of said bi-convex lens means.

Claim 16

A photographic lens system according to claim 5, satisfying the following condition: 0.08<n 4 -n 3 <0.3 where n 3 is the index of refraction of the said positive lens and n 4 is the index of refraction of said negative lens.

Claim 17

A photographic objective lens system consisting of: positive meniscus lens means of forward convexity, bi-concave lens means arranged toward the image end of said positive meniscus lens means, bi-convex lens means arranged toward the image end of said bi-concave lens means, and negative meniscus lens means of forward concavity arranged toward the image end of said bi-convex lens means, said positive meniscus lens means, said bi-concave lens means, and said bi-convex means being arranged for movement along a common optical axis for effecting focusing of said photographic lens system, said lens means having surfaces satisfying the following:

Claim 18

A photographic objective lens system consisting of: positive meniscus lens means of forward convexity, bi-concave lens means arranged toward the image end of said positive meniscus lens means, bi-convex lens means arranged toward the image end of said bi-concave lens means, and negative meniscus lens means of forward concavity arranged toward the image end of said bi-convex lens means, said positive meniscus lens means, said bi-concave lens means, and said bi-convex means being arranged for movement along a common optical axis for effecting focusing of said photographic lens system, said lens means having surfaces satisfying the following:

Claim 19

2<r 2 /r 1 <3.8 where r 1 is the radius of curvature of the front surface of the positive meniscus lens and r 2 is the radius of curvature of the rear surface of the positive meniscus lens, and wherein 0.6<|f A |/f<1.0, f A <0 where f is the focal length of the entire system and f A is the focal length of the air lens formed between the positive meniscus lens means and the bi-concave lens means.

Claim 20

2<r 2 /r 1 <3.8 where r 1 is the radius of curvature of the front surface of the positive meniscus lens and r 2 is the radius of curvature of the rear surface of the positive meniscus lens, and wherein 0.6<|f A |/f<1.0, f A <0 where f is the focal length of the entire system and f A is the focal length of the air lens formed between the positive meniscus lens means and the bi-concave lens means.