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US 6,633,431 B2Granted
Optical system and optical apparatus having the same
AssigneeCanon Kabushiki Kaisha
InventorTakeshi Akiyama
Life of this patent
Estimating the term…
Abstract
An optical system comprises, in succession from the object side, a first optical element of negative optical power, a second optical element of positive optical power, and a third optical element of negative optical power, at least one of the first to third optical elements being a refracting optical element having a reflecting curved surface.
Claims12
An optical system comprising, in succession from the light entrance side:
- a first optical element of negative optical power;
- a second optical element of positive optical power;
- and
- a third optical element of negative optical power,
- wherein at least one of said first to third optical elements is a reflecting optical element having a plurality of reflecting curved surfaces,
- wherein said optical system further comprises an aperture stop disposed between two of said first to third optical elements, and
- wherein the image of said aperture stop by the optical element disposed more adjacent to the object side than said aperture stop is formed at a negative magnification.
4 more elements
An optical system comprising, in succession from the light entrance side:
- a first optical unit of negative optical power;
- a second optical unit of positive optical power;
- and
- a third optical unit of negative optical power,
- wherein the positions of at least two of said first to third optical units relative to the imaging plane are changed to change distances between said first to third optical units and thereby effect zooming, and
- wherein at least one of said first to third optical units has a reflecting optical element having a plurality of reflecting curved surfaces.
3 more elements
Dependencies are inferred from the claim text.