Image scanner overall length reduced compared to conventional scanners; errors in the relative positions of lens and image scanning element are reduced

摘要

The image scanner has a refractive index distribution lens (1) with a refractive index distribution which is essentially proportional to the square of the distance from the optical axis (2) in a cross-section vertical to the optical axis. This lens is used as an imaging lens near the imaging surface (5) of an image scanning element (4).