Image forming optical system and electronic image pickup apparatus using the same

An image forming optical system comprising:

• a lens component which comprises a lens L1 which is made of a transparent material having Abbe's number νd1, an intermediate layer L2 which is made of a transparent material having Abbe's number νd2, and a lens L3 which is made of a transparent material having Abbe's number νd3, wherein
• the intermediate layer L2 is in a close contact with an optical surface B of the lens L1, and
• a shape of an optical surface C of the intermediate layer L2 is an aspheric shape, and
• the lens L3 is in a close contact with the optical surface C, and
• the image forming optical system satisfies the following conditions
• 0.012<1/νd3−1/νd1<0.090 (1)
• 0.010<1/νd3−1/νd2 (2)
• 1.65<nd1 (4)
• where,
• νd1 denotes Abbe's number (nd1−1)/(nF1−nC1) of the lens L1,
• νd2 denotes Abbe's number (nd2−1)/(nF2−nC2) of the intermediate layer L2, and
• νd3 denotes Abbe's number (nd3−1)/(nF3−nC3) of the lens L3,
• where,
• nd1, nC1, and nF1 denote refractive indices of the lens L1 for a d-line, a C-line, and an F-line respectively,
• nd2, nC2, and nF2 denote refractive indices of the intermediate layer L2 for the d-line, the C-line, and the F-line respectively, and
• nd3, nC3, and nF3 denote refractive indices of the lens L3 for the d-line, the C-line, and the F-line respectively,
• wherein the image forming optical system satisfies the following condition
• −0.70<φ3/φ1<−0.10 (5)
• |φ1|>|φ3|>|φ2| (6)
• where,
• φ1 denotes a refractive power in air, of the lens L1,
• φ2 denotes a refractive power in air, of the intermediate layer L2, and
• φ3 denotes a refractive power in air, of the lens L3.

An image forming optical system comprising:

• a lens component which comprises a lens L1 which is made of a transparent material having Abbe's number νd1, an intermediate layer L2 which is made of a transparent material having Abbe's number νd2, and a lens L3 which is made of a transparent material having Abbe's number νd3, wherein
• the intermediate layer L2 is in a close contact with an optical surface B of the lens L1, and
• a shape of an optical surface C of the intermediate layer L2 is an aspheric shape, and
• the lens L3 is in a close contact with the optical surface C, and
• the image forming optical system satisfies the following conditions
• 0.012<1/νd3−1/νd1<0.090 (1)
• 0.010<1/νd3−1/νd2 (2)
• 1.65<nd1 (4)
• where,
• νd1 denotes Abbe's number (nd1−1)/(nF1−nC1) of the lens L1,
• νd2 denotes Abbe's number (nd2−1)/(nF2−nC2) of the intermediate layer L2, and
• νd3 denotes Abbe's number (nd3−1)/(nF3−nC3) of the lens L3,
• where,
• nd1, nC1, and nF1 denote refractive indices of the lens L1 for a d-line, a C-line, and an F-line respectively,
• nd2, nC2, and nF2 denote refractive indices of the intermediate layer L2 for the d-line, the C-line, and the F-line respectively, and
• nd3, nC3, and nF3 denote refractive indices of the lens L3 for the d-line, the C-line, and the F-line respectively,
• wherein the intermediate layer L2 is made of an energy curable resin, and a thickness on an optical axis, of the intermediate layer L2 is in a range of 0.03 mm to 2.00 mm.

An image forming optical system comprising:

• a lens component which comprises a lens L1 which is made of a transparent material having Abbe's number νd1, an intermediate layer L2 which is made of a transparent material having Abbe's number νd2, and a lens L3 which is made of a transparent material having Abbe's number νd3, wherein
• the intermediate layer L2 is in a close contact with an optical surface B of the lens L1, and
• a shape of an optical surface C of the intermediate layer L2 is an aspheric shape, and
• the lens L3 is in a close contact with the optical surface C, and
• the image forming optical system satisfies the following conditions
• 0.012<1/νd3−1/νd1<0.090 (1)
• 0.010<1/νd3−1/νd2 (2)
• 1.65<nd1 (4)
• where,
• νd1 denotes Abbe's number (nd1−1)/(nF1−nC1) of the lens L1,
• νd2 denotes Abbe's number (nd2−1)/(nF2−nC2) of the intermediate layer L2, and
• νd3 denotes Abbe's number (nd3−1)/(nF3−nC3) of the lens L3,
• where,
• nd1, nC1, and nF1 denote refractive indices of the lens L1 for a d-line, a C-line, and an F-line respectively,
• nd2, nC2, and nF2 denote refractive indices of the intermediate layer L2 for the d-line, the C-line, and the F-line respectively, and
• nd3, nC3, and nF3 denote refractive indices of the lens L3 for the d-line, the C-line, and the F-line respectively,
• wherein the lens L3 is made of an energy curable resin, and a thickness on the optical axis, of the lens L3 is in a range of 0.03 mm to 2.00 mm.

An image forming optical system comprising:

• a lens component which comprises a lens L1 which is made of a transparent material having Abbe's number νd1, an intermediate layer L2 which is made of a transparent material having Abbe's number νd2, and a lens L3 which is made of a transparent material having Abbe's number νd3, wherein
• the intermediate layer L2 is in a close contact with an optical surface B of the lens L1, and
• a shape of an optical surface C of the intermediate layer L2 is an aspheric shape, and
• the lens L3 is in a close contact with the optical surface C, and
• the image forming optical system satisfies the following conditions
• 0.012<1/νd3−1/νd1<0.090 (1)
• 0.010<1/νd3−1/νd2 (2)
• 1.65<nd1 (4)
• where,
• νd1 denotes Abbe's number (nd1−1)/(nF1−nC1) of the lens L1,
• νd2 denotes Abbe's number (nd2−1)/(nF2−nC2) of the intermediate layer L2, and
• νd3 denotes Abbe's number (nd3−1)/(nF3−nC3) of the lens L3,
• where,
• nd1, nC1, and nF1 denote refractive indices of the lens L1 for a d-line, a C-line, and an F-line respectively,
• nd2, nC2, and nF2 denote refractive indices of the intermediate layer L2 for the d-line, the C-line, and the F-line respectively, and
• nd3, nC3, and nF3 denote refractive indices of the lens L3 for the d-line, the C-line, and the F-line respectively,
• wherein the image forming optical system satisfies the following condition
• −0.0700≦θgF3−θgF1≦0.1500 (11)
• where,
• θgF1 denotes a partial dispersion ratio (ng1−nF1)/(nF1−nC1) of the lens L1,
• θgF3 denotes a partial dispersion ratio (ng3−nF3)/(nF3−nC3) of the lens L3,
• where,
• nd1, nC1, nF1, and ng1 denote refractive indices of the lens L1 for the d-line, the C-line, the F-line, and the g-line respectively.

An image forming optical system comprising:

• a lens component which comprises a lens L1 which is made of a transparent material having Abbe's number νd1, an intermediate layer L2 which is made of a transparent material having Abbe's number νd2, and a lens L3 which is made of a transparent material having Abbe's number νd3, wherein
• the intermediate layer L2 is in a close contact with an optical surface B of the lens L1, and
• a shape of an optical surface C of the intermediate layer L2 is an aspheric shape, and
• the lens L3 is in a close contact with the optical surface C, and
• the image forming optical system satisfies the following conditions
• 0.012<1/νd3−1/νd1<0.090 (1)
• 0.010<1/νd3−1/νd2 (2)
• 1.65<nd1 (4)
• where,
• νd1 denotes Abbe's number (nd1−1)/(nF1−nC1) of the lens L1,
• νd2 denotes Abbe's number (nd2−1)/(nF2−nC2) of the intermediate layer L2, and
• νd3 denotes Abbe's number (nd3−1)/(nF3−nC3) of the lens L3,
• where,
• nd1, nC1, and nF1 denote refractive indices of the lens L1 for a d-line, a C-line, and an F-line respectively,
• nd2, nC2, and nF2 denote refractive indices of the intermediate layer L2 for the d-line, the C-line, and the F-line respectively, and
• nd3, nC3, and nF3 denote refractive indices of the lens L3 for the d-line, the C-line, and the F-line respectively,
• wherein the lens component has a combined positive refractive power.

An image forming optical system comprising:

• a lens component which comprises a lens L1 which is made of a transparent material having Abbe's number νd1, an intermediate layer L2 which is made of a transparent material having Abbe's number νd2, and a lens L3 which is made of a transparent material having Abbe's number νd3, wherein
• the intermediate layer L2 is in a close contact with an optical surface B of the lens L1, and
• a shape of an optical surface C of the intermediate layer L2 is an aspheric shape, and
• the lens L3 is in a close contact with the optical surface C, and
• the image forming optical system satisfies the following conditions
• 0.012<1/νd3−1/νd1<0.090 (1)
• 0.010<1/νd3−1/νd2 (2)
• 1.65<nd1 (4)
• where,
• νd1 denotes Abbe's number (nd1−1)/(nF1−nC1) of the lens L1,
• νd2 denotes Abbe's number (nd2−1)/(nF2−nC2) of the intermediate layer L2, and
• νd3 denotes Abbe's number (nd3−1)/(nF3−nC3) of the lens L3,
• where,
• nd1, nC1, and nF1 denote refractive indices of the lens L1 for a d-line, a C-line, and an F-line respectively,
• nd2, nC2, and nF2 denote refractive indices of the intermediate layer L2 for the d-line, the C-line, and the F-line respectively, and
• nd3, nC3, and nF3 denote refractive indices of the lens L3 for the d-line, the C-line, and the F-line respectively,
• wherein
• the image forming optical system is a zooming optical system, and
• the zooming optical system, in order from an object side, comprises a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a rear group having a positive refractive power, and
• the rear group comprises a plurality of lens groups of which, relative distances are variable at the time of zooming, and
• relative distances between the first lens group, the second lens group, and the rear group are variable at the time of zooming, and
• the lens component is used in the first lens group.

An image forming optical system comprising:

• a lens component which comprises a lens L1 which is made of a transparent material having Abbe's number νd1, an intermediate layer L2 which is made of a transparent material having Abbe's number νd2, and a lens L3 which is made of a transparent material having Abbe's number νd3, wherein
• the intermediate layer L2 is in a close contact with an optical surface B of the lens L1, and
• a shape of an optical surface C of the intermediate layer L2 is an aspheric shape, and
• the lens L3 is in a close contact with the optical surface C, and
• the image forming optical system satisfies the following conditions
• 0.012<1/νd3−1/νd1<0.090 (1)
• 0.010<1/νd3−1/νd2 (2)
• 1.65<nd1 (4)
• where,
• νd1 denotes Abbe's number (nd1−1)/(nF1−nC1) of the lens L1,
• νd2 denotes Abbe's number (nd2−1)/(nF2−nC2) of the intermediate layer L2, and
• νd3 denotes Abbe's number (nd3−1)/(nF3−nC3) of the lens L3,
• where,
• nd1, nC1, and nF1 denote refractive indices of the lens L1 for a d-line, a C-line, and an F-line respectively,
• nd2, nC2, and nF2 denote refractive indices of the intermediate layer L2 for the d-line, the C-line, and the F-line respectively, and
• nd3, nC3, and nF3 denote refractive indices of the lens L3 for the d-line, the C-line, and the F-line respectively,
• wherein
• the lens L1 has the optical surface A, and
• the lens L3 has an optical surface D, and
• both the optical surface A and the optical surface D are surfaces in contact with air,
• wherein
• when coordinate axes are let to be such that, an optical axial direction is z, and a direction perpendicular to the optical axis is h, R is let to be a radius of curvature on an optical axis, of a spherical surface component, k is let to be a conical constant, and A4, A6, A8, A10, . . . are let to be aspherical coefficients, and when a shape of the aspheric surface is expressed by the following expression (13)
• z=h2/R[1+{1−(1+k)h2/R2}1/2]+A4h4+A6h6+A8h8+A10h10+ (13), and
• when an amount of deviation is expressed by the following expression (14)
• Δz=z−h2/R[1+{1−h2/R2}1/2] (14)
• the image forming optical system satisfies the following conditional expression (15)
• (ΔzA(h)+ΔzD(h))/2≦Δzc(h)≦10·(ΔzA(h)+ΔzD(h))/2(provided that h=2.5a) (15)
• where,
• zA is a shape of the optical surface A, which is according to expression (13),
• zD is a shape of the optical surface D, which is according to expression (13), and
• zC is a shape of the optical surface C, which is according to expression (13), and
• ΔzA denotes an amount of deviation at the optical surface A, which is an amount according to expression (14),
• ΔzD denotes an amount of deviation at the optical surface D, which is an amount according to expression (14),
• ΔzC denotes an amount of deviation at the optical surface C, which is an amount according to expression (14),
• RC is a paraxial radius of curvature of the optical surface C(≦0),
• a is an amount according to the following conditional expression (16)
• a=(y10)2·log10γ/fw (16)
• and moreover in expression (16),
• y10 is the maximum image height,
• fw is a focal length of the overall image forming optical system at a wide angle end,
• γ is a zooming ratio in the image forming optical system (a focal length of the overall image forming optical system at a telephoto end/a focal length of the overall image forming optical system at the wide angle end), and
• moreover, for letting an apex of each surface to be an origin point, z(0)=0 all the time.

An electronic image pickup apparatus comprising:

• an image forming optical system comprising;
• a lens component which comprises a lens L1 which is made of a transparent material having Abbe's number νd1, an intermediate layer L2 which is made of a transparent material having Abbe's number νd2, and a lens L3 which is made of a transparent material having Abbe's number νd3, wherein
• the intermediate layer L2 is in a close contact with an optical surface B of the lens L1, and
• a shape of an optical surface C of the intermediate layer L2 is an aspheric shape, and
• the lens L3 is in a close contact with the optical surface C, and
• the image forming optical system satisfies the following conditions
• 0.012<1/νd3−1/νd1<0.090 (1)
• 0.010<1/νd3−1/νd2 (2)
• 1.65<nd1 (4)
• where,
• νd1 denotes Abbe's number (nd1−1)/(nF1−nC1) of the lens L1,
• νd2 denotes Abbe's number (nd2−1)/(nF2−nC2) of the intermediate layer L2, and
• νd3 denotes Abbe's number (nd3−1)/(nF3−nC3) of the lens L3,
• where,
• nd1, nC1, and nF1 denote refractive indices of the lens L1 for a d-line, a C-line, and an F-line respectively,
• nd2, nC2, and nF2 denote refractive indices of the intermediate layer L2 for the d-line, the C-line, and the F-line respectively, and
• nd3, nC3, and nF3 denote refractive indices of the lens L3 for the d-line, the C-line, and the F-line respectively,
• an electronic image pickup element;
• and
• an image processing unit which processes image data which has been obtained by picking up an image formed by the image forming optical system by the electronic image pickup element, and outputs as image data in which, a shape of the image has been changed, wherein
• the image forming optical system is a zoom lens, and
• the zoom lens satisfies the following conditional expression (16) at the time of infinite object point focusing,
• 0.7<y07/(fw·tan ω07w)<0.97 (16)
• where,
• y07 is expressed as y07=0.7·y10, when a distance (the maximum image height) from a center up to the farthest point on an effective image pickup surface (on a surface on which an image can be picked up) of the electronic image pickup element is let to be y10,
• ω07w is an angle with respect to an optical axis in an object-point direction corresponding to an image point from a center on the image pickup surface up to a position of y07, at a wide angle end, and
• fw is a focal length of the overall image forming zoom lens system at the wide angle end.

An image forming optical system comprising:

• a lens component which comprises a lens L1 which is made of a transparent material having Abbe's number νd1, an intermediate layer L2 which is made of a transparent material having Abbe's number νd2, and a lens L3 which is made of a transparent material having Abbe's number νd3, wherein
• the intermediate layer L2 is in a close contact with an optical surface B of the lens L1,
• a shape of an optical surface C of the intermediate layer L2 is an aspheric shape, and
• the lens L3 is in a close contact with the optical surface C,
• the lens L1 has the optical surface A, and
• the lens L3 has an optical surface D, and
• both the optical surface A and the optical surface D are surfaces in contact with air,
• when coordinate axes are let to be such that, an optical axial direction is z, and a direction perpendicular to the optical axis is h, R is let to be a radius of curvature on an optical axis, of a spherical surface component, k is let to be a conical constant, and A4, A6, A8, A10, . . . are let to be aspherical coefficients, and when a shape of the aspheric surface is expressed by the following expression (13)
• z=h2/R[1+{1−(1+k)h2/R2}1/2]+A4h4+A6h6+A8h8+A10h10+ (13), and
• when an amount of deviation is expressed by the following expression (14)
• Δz=z−h2/R[1+{1−h2/R2}1/2] (14)
• the image forming optical system satisfies the following conditions(1), (2) and (15),
• 0.012<1/νd3−1/νd1<0.090 (1)
• 0.010<1/νd3−1/νd2 (2)
• (ΔzA(h)+ΔzD(h))/2≦ΔzC(h)≦10·(ΔzA(h)+ΔzD(h))/2(provided that h=2.5a) (15)
• where,
• νd1 denotes Abbe's number (nd1−1)/(nF1−nC1) of the lens L1,
• νd2 denotes Abbe's number (nd2−1)/(nF2−nC2) of the intermediate layer L2, and
• νd3 denotes Abbe's number (nd3−1)/(nF3−nC3) of the lens L3,
• where,
• nd1, nC1, and nF1 denote refractive indices of the lens L1 for a d-line, a C-line, and an F-line respectively,
• nd2, nC2, and nF2 denote refractive indices of the intermediate layer L2 for the d-line, the C-line, and the F-line respectively, and
• nd3, nC3, and nF3 denote refractive indices of the lens L3 for the d-line, the C-line, and the F-line respectively,
• zA is a shape of the optical surface A, which is according to expression (13),
• zD is a shape of the optical surface D, which is according to expression (13), and
• zC is a shape of the optical surface C, which is according to expression (13), and
• ΔzA denotes an amount of deviation at the optical surface A, which is an amount according to expression (14),
• ΔzD denotes an amount of deviation at the optical surface D, which is an amount according to expression (14),
• ΔzC denotes an amount of deviation at the optical surface C, which is an amount according to expression (14),
• RC is a paraxial radius of curvature of the optical surface C(≦0),
• a is an amount according to the following conditional expression (16)
• a=(y10)2·log10γ/fw (16)
• and moreover in expression (16),
• y10 is the maximum image height,
• fw is a focal length of the overall image forming optical system at a wide angle end,
• γ is a zooming ratio in the image forming optical system (a focal length of the overall image forming optical system at a telephoto end/a focal length of the overall image forming optical system at the wide angle end), and
• moreover, for letting an apex of each surface to be an origin point, z(0)=0 all the time.

An image forming optical system comprising:

• a lens component which comprises a lens L1 which is made of a transparent material having Abbe's number νd1, an intermediate layer L2 which is made of a transparent material having Abbe's number νd2, and a lens L3 which is made of a transparent material having Abbe's number νd3, wherein
• the intermediate layer L2 is in a close contact with an optical surface B of the lens L1, and
• a shape of an optical surface C of the intermediate layer L2 is an aspheric shape, and
• the lens L3 is in a close contact with the optical surface C, and
• the image forming optical system satisfies the following conditions (1) and (2),
• further in a rectangular coordinate system with a horizontal axis let to be νd3 and a vertical axis let to be θgF3, when a straight line expressed by
• θgF3=α3×νd3+βgF3 (provided that α3=−0.00566) is set,
• an area which is determined by a straight line when it is a lower limit value of a range of the following conditional expression (7) and a straight line when it is an upper limit value of the range of the following conditional expression (7), and
• an area determined by the following conditional expression (9) include θgF3 and νd3 of the lens L3,
• in a rectangular coordinate system with a horizontal axis let to be νd3 and a vertical axis let to be nd3, when a straight line expressed by
• nd3=a3×νd3+b3 (provided that a3=−0.0267) is set,
• an area which is determined by a straight line when it is a lower limit value of a range of the following conditional expression (8) and a straight line when it is an upper limit value of the range of the following conditional expression (8), and
• an area determined by the following conditional expression (9) include nd3 and νd3 of the lens L3,
• 0.012<1/νd3−1/νd1<0.090 (1)
• 0.010<1/νd3−1/νd2 (2)
• 0.6520<βgF3<0.8150 (7)
• 2.0<b3<2.4 (provided that nd3>1.3) (8)
• 10<νd3<35 (9)
• where,
• νd1 denotes Abbe's number (nd1−1)/(nF1−nC1) of the lens L1,
• νd2 denotes Abbe's number (nd2−1)/(nF2−nC2) of the intermediate layer L2, and
• νd3 denotes Abbe's number (nd3−1)/(nF3−nC3) of the lens L3,
• θgF3 denotes a partial dispersion ratio (ng3−nF3)/(nF3−nC3) of the lens L3, where,
• nd1, nC1, and nF1 denote refractive indices of the lens L1 for a d-line, a C-line, and an F-line respectively,
• nd2, nC2, and nF2 denote refractive indices of the intermediate layer L2 for the d-line, the C-line, and the F-line respectively, and
• nd3, nC3, and nF3 denote refractive indices of the lens L3 for the d-line, the C-line, and the F-line respectively.