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US 2003/0112531 A1Published application
Molded lens, scanning lens, optical scanner and image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorsMasaaki Kuroda, Osamu Suzuki
Life of this patent
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Abstract
The present invention provides a plastic lens, used in an optical system of an optical image recording apparatus, which is low in birefringence, and is less susceptible to displacement of focus caused by resistance to environment. At least a part of a non-effective area is concave, and there is a sink mark in the concave portion. The shape of the concave portion is determined so as to achieve a GI ratio (Δf/f0)≦5%.
Claims13
A molded lens used in an optical system of an image recorder, wherein:
- at least a part of a non-effective area through which an image forming flux does not pass, has a concave shape.
A molded scanning lens, wherein:
- within the sub-scanning section, at least a part of the non-effective area through which the scanning flux does not pass is convex in shape.
Dependencies are inferred from the claim text.