Zoom lens system
AssigneeMinolta Co., Ltd.
InventorsKeijiro Sakamoto, Kazuharu Kagoshima
Life of this patent
Estimating the term…
Abstract
A zoom lens system consists of, in order from the enlargement side to the reduction side, a first lens unit having a negative optical power and a second lens unit having a positive optical power. In the zoom lens system, either the first or the second lens unit has at least one surface having an optical power of diffraction.
Claims5
A zoom lens system, comprising, in order from an enlargement side to a reduction side:
- a first lens unit having a negative optical power;
- and
- a second lens unit having a positive optical power,
- wherein said first lens unit has a surface having an optical power of diffraction and wherein said zoom lens system fulfills the following conditions:
- 0.001<|φDn/φn|<0.15
- where
- φDn represents the optical power of diffraction of the surface included in said first lens unit;
- and
- φn represents a composite optical power of refraction of all surfaces included in said first lens unit.
A zoom lens system, comprising, in order from an enlargement side to a reduction side:
- a first lens unit having a negative optical power;
- and
- a second lens unit having a positive optical power,
- wherein said first lens unit has a surface having an optical power of diffraction and wherein said zoom lens system fulfills the following conditions:
- |φDn/φ1<0.07
- where
- φDn represents the optical power of diffraction of the surface included in said first lens unit;
- and
- φ1 represents a composite optical power of refraction and diffraction of the lens element which has the surface having an optical power of diffraction and which is included in said first lens unit.
A zoom lens system, comprising, in order from an enlargement side to a reduction side:
- a first lens unit having a negative optical power;
- and
- a second lens unit having a positive optical power,
- wherein said second lens unit has a surface having an optical power of diffraction and wherein said zoom lens system fulfills the following conditions:
- 0.01<φDp/φp<0.025
- where
- φDp represents the optical power of diffraction of the surface included in said second lens unit;
- and
- φp represents a composite optical power of refraction of all surfaces included in said second lens unit.
A zoom lens system, comprising, in order from an enlargement side to a reduction side:
- a first lens unit having a negative optical power;
- and
- a second lens unit having a positive optical power,
- wherein said second lens unit has a surface having an optical power of diffraction and wherein said zoom lens system fulfills the following conditions:
- 0.005<φDp/φ2<0.08
- where
- φDp represents the optical power of diffraction of the surface included in said second lens unit;
- and
- φ2 represents a composite optical power of refraction and diffraction of the lens element which has the surface having an optical power of diffraction and which is included in said second lens unit.
A zoom lens system, comprising, in order from an enlargement side to a reduction side:
- a first lens unit having a negative optical power;
- and
- a second lens unit having a positive optical power.
- wherein either said first or second lens unit has at least one surface having an optical power of diffraction and wherein said zoom lens system fulfills the following condition:
- −1<φn/φp<−0.5
- where
- φn represents a composite optical power of refraction of all surfaces included in said first lens unit;
- and
- φp represents a composite optical power of refraction of all surfaces included in said second lens unit.
Dependencies are inferred from the claim text.