Illuminating device, image reading apparatus, and image forming apparatus

摘要

Provided is an illuminating device including a cylindrical lens in which a light incidence surface and a light emission surface, which are opposite to each other, extend in a longitudinal direction, and a light source that is disposed in such a manner that a positional relationship between a paraxial virtual image of the light source due to the light incidence surface of the cylindrical lens and a center of curvature of the light emission surface is in a predetermined range.

主权项

1. An illuminating device comprising:
a cylindrical lens in which a light incidence surface and a light emission surface, which are opposite to each other, extend in a longitudinal direction; and a light source that is disposed in such a manner that a paraxial virtual image of the light source due to the light incidence surface of the cylindrical lens is set to be in a predetermined range including a center of curvature of the light emission surface so that convergence characteristics with respect to skew light beams due to a distance between a light source and a light incidence surface are reduced.