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US 10,591,842 B2Granted
Lens array, lens unit, exposure device, LED head, and image forming apparatus
AssigneeOki Data Corporation
InventorAkihiro Yamamura
Life of this patent
Estimating the term…
Abstract
Provided are a lens array, a lens unit, an exposure device, an LED head, and an image forming apparatus. The lens array includes a plurality of lenses arranged so as to form an array. Each of the plurality of lenses is configured so that a contour focal length which is a focal length of a ray incident on a first position separate from an optical axis is longer than a paraxial focal length which is a focal length of a ray incident on a second position in the vicinity of the optical axis.
Claims11
A lens array comprising a plurality of lenses arranged so as to form an array, wherein
- each of the plurality of lenses has an optical axis,
- each of the plurality of lenses is configured so that a contour focal length which is a focal length of a ray incident on a first position separate from the optical axis is longer than a paraxial focal length which is a focal length of a ray incident on a second position in a vicinity of the optical axis, and
- in each of the plurality of lenses, the second position is closer to the optical axis than is the first position.
A lens unit comprising:
- a first lens array including a plurality of first lenses arranged so as to form an array;
- and
- a second lens array including a plurality of second lenses arranged so as to form an array, wherein
- optical axes of the plurality of second lenses respectively coincide with optical axes of the plurality of first lenses,
- each of the plurality of first lenses is configured so that a first contour focal length which is a focal length of a ray incident on a first position separate from the optical axis is longer than a first paraxial focal length which is a focal length of a ray incident on a second position in the vicinity of the optical axis,
- each of the plurality of second lenses is configured so that a second contour focal length which is a focal length of a ray incident on a third position separate from the optical axis is longer than a second paraxial focal length which is a focal length of a ray incident on a fourth position in the vicinity of the optical axis,
- in each of the plurality of first lenses, the second position is closer to the optical axis than is the first position, and
- in each of the plurality of second lenses, the fourth position is closer to the optical axis than is the third position.
5 more elements
Dependencies are inferred from the claim text.