JP2009093118A5 - - Google Patents

Claims (9)

In order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a plurality of lens groups as a whole are configured by a subsequent lens group having a positive refractive power. in the zoom lens spacing group adjacent lens changes, the second lens group is composed of a negative lens, and a compound optical element resin layer is formed of a positive refractive power on the surface of the negative lens, wherein the radius of curvature of the object side and the image side of the resin layer each r1, r2, wherein each [nu ₂₂₂ material Abbe number and the partial dispersion ratio of the resin layer, theta _222, the focal length of the resin layer f _222, -0.95 <(r1 + r2) / (r1-r2) <0 when the focal lengths at the wide-angle end and the telephoto end of the entire system are fw and ft, respectively.
0.755 <θ ₂₂₂ − (− 1.665 × 10 ⁻⁷ · ν ₂₂₂ ³ + 5.213 × 10 ⁻⁵ · ν ₂₂₂ ² −5.656 × 10 ⁻³ · ν ₂₂₂ ) <1.011
5 <ν ₂₂₂ <30
0.38 <√ (fw · ft) / f ₂₂₂ <0.80
A zoom lens satisfying the following conditional expression: 2. The zoom lens according to claim 1, wherein the surface of the resin layer in contact with air is an aspherical surface having a positive refractive power that increases from the central portion toward the peripheral portion. When the focal length of the negative lens and the Abbe number of the material constituting the composite optical element are respectively f ₂₂₁ and ν ₂₂₁ ,
0.007 <(√ (fw · ft)) · (1 / (f ₂₂₁ · ν ₂₂₁ ) + 1 / (f ₂₂₂ · ν ₂₂₂ )) <0.05
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the focal length of the composite optical element is f ₂₂ ,
−0.05 <√ (fw · ft) / f ₂₂ <0.50
The zoom lens according to any one of claims 1 to 3, characterized by satisfying the conditional expression. When the center thickness of the negative lens constituting the composite optical element is t ₂₂₁ and the center thickness of the resin layer is t ₂₂₂ ,
0.1 <t ₂₂₂ / t ₂₂₁ <1.5
The zoom lens according to any one of claims 1 to 4, characterized by satisfying the conditional expression. When the refractive index of the material of the resin layer is N ₂₂₂ ,
1.60 <N ₂₂₂ <1.85
The zoom lens according to any one of claims 1 to 5, characterized by satisfying the conditional expression. When the Abbe number of the material of the negative lens constituting the composite optical element is ν ₂₂₁ , 25 <ν ₂₂₁ −ν ₂₂₂ <60
The zoom lens according to any one of claims 1 to 6, characterized by satisfying the conditional expression. The zoom lens according to any one of claims 1 to 7, all the lens groups during zooming to the telephoto end from the wide-angle end, characterized in that movement. A zoom lens according to any one of claims 1 to 8, the image pickup apparatus characterized by comprising a solid-state image sensor for receiving an image formed by the zoom lens.