Projection optical system and projector
AssigneeKonica Minolta, Inc.
InventorAtsuo Masui
Life of this patent
Estimating the term…
Abstract
A projection optical system capable of performing magnification projection of an image displayed on an image display surface, with a 40° half angle of view, or more includes, in an order from a magnification side: a first optical system; and a second optical system, wherein the second optical system forms an intermediate image of the image, the first optical system performs magnification projection of the intermediate image, and the following conditional expressions (1) and (2) are satisfied: 1<Ff/|Fw|<2 . . . (1), 0.4<Lf/Lw<0.6 . . . (2), where, Ff: a focal length of the first optical system, Fw: a focal length of an entire system, Lf: a distance on optical axis, from a most-magnification-side surface vertex to the intermediate image, in the first optical system, Lw: an entire length of a lens.
Claims11
A projection optical system capable of performing magnification projection of an image displayed on an image display surface, with a 40° half angle of view, or more, the projection optical system comprising, in an order from a magnification side:
- a first optical system;
- and
- a second optical system,
- wherein the second optical system forms an intermediate image of the image,
- the first optical system performs magnification projection of the intermediate image, and
- the following conditional expressions (1) and (2) are satisfied:
- 1.3<Ff/|Fw|<1.7 (1)
- 0.4<Lf/Lw<0.6 (2),
- where,
- Ff:
- a focal length of the first optical system,
- Fw:
- a focal length of an entire system at a maximum angle of view in a case where the projection optical system is a zoom lens,
- Lf:
- a distance on optical axis, from a most-magnification-side surface vertex to the intermediate image, in the first optical system, and
- Lw:
- an entire length of a lens, at the maximum angle of view in a case where the projection optical system is a zoom lens.
A projector comprising:
- an image display element having the image display surface;
- and
- a projection optical system that performs magnification projection of an image displayed on the image display surface, onto a screen surface, the projection optical system comprising:
- a second optical system,
- wherein the second optical system forms an intermediate image of the image,
- the first optical system performs magnification projection of the intermediate image, and
- the following conditional expressions (1) and (2) are satisfied:
- 1.3<Ff/|Fw|<1.7 (1)
- 0.4<Lf/Lw<0.6 (2),
- where,
- Ff:
- a focal length of the first optical system,
- Fw:
- a focal length of an entire system at a maximum angle of view in a case where the projection optical system is a zoom lens,
- Lf:
- a distance on optical axis, from a most-magnification-side surface vertex to the intermediate image, in the first optical system, and
- Lw:
- an entire length of a lens at the maximum angle of view in a case where the projection optical system is a zoom lens.
Dependencies are inferred from the claim text.