Image formation optical system and image reading apparatus using the same
AssigneeCanon Kabushiki Kaisha
InventorTadao Hayashide
Life of this patent
Estimating the term…
Abstract
To provide an image formation optical system which is excellent in image formation performance while reducing an opening angle of an anamorphic lens, and an image reading apparatus using the same. When a thickness of an anamorphic lens is da, a thickness of a meniscus lens arranged adjacent to the anamorphic lens is dm, an interval between the anamorphic lens and the meniscus lens adjacent thereto is tin, and a distance between a lens surface of the lens, of both the lenses, nearest an aperture stop, and a lens surface of the lens, other than both the lenses, facing that lens surface is tout, the constituent elements are set so as to satisfy the following condition: tin<dm+da<tout.
Claims19
An image formation optical system for imaging image information of an original on a photoelectric conversion device having a plurality of pixels arranged in one-dimensional direction,
- wherein a lens barrel for holding at least one of rotation symmetric lens having a shape which is rotation symmetric with respect to an optical axis, and a lens barrel for holding a rotation asymmetric lens having a rotation asymmetric shape are assembled so as to be mutually rotatable for adjustment.
An image formation optical system for imaging image information of an original on a photoelectric conversion device having a plurality of pixels arranged in one-dimensional direction, comprising:
- at least one of rotation symmetric lens having a shape which is rotation symmetric with respect to an optical axis and held inside a lens barrel;
- and
- a rotation asymmetric lens having a rotation asymmetric shape and held outside the lens barrel,
- wherein the at least one of rotation symmetric lens and the rotation asymmetric lens are assembled so as to be mutually rotatable for adjustment.
An image reading apparatus having:
- an image formation optical system for imaging image information of an original;
- a barrel for holding the image formation optical system;
- barrel supporting means for supporting the barrel;
- and reading means arranged in an image formation position of the image formation optical system and having a plurality of light receiving elements arranged in one-dimensional direction,
- wherein the image formation optical system has at least one of rotation asymmetric lens having a rotation asymmetric shape, and a second alignment reference surface provided in the rotation asymmetric lens is brought into contact with a first alignment reference surface provided in the barrel supporting means to align certain one direction of a refracting power of the rotation asymmetric lens with the direction of arrangement of the plurality of light receiving elements.
An image formation optical system for imaging image information of an original on a photoelectric conversion device having a plurality of pixels arranged in one-dimensional direction,
- wherein the image formation optical system has an aperture stop, at least one of a plurality of lenses constituting the image formation optical system is an anamorphic lens, and a meniscus lens is arranged adjacent to the anamorphic lens, and
- when a thickness of the anamorphic lens is da, a thickness of the meniscus lens is dm, an interval between the anamorphic lens and the meniscus lens adjacent thereto is tin, and a distance between a lens surface of the lens of both the lenses nearest the aperture stop and a lens surface of the lens, other than both the lenses, facing the lens surface of the lens of both the lenses nearest the aperture stop is tout, the following condition is satisfied:
- tin<dm+da<tout.
Dependencies are inferred from the claim text.