Patent ID: 7852522
Filing Date: 2010-12-14
Classification: G03B

Abstract:
1. An original-document illumination apparatus illuminating an illuminated area having a length and a width, comprising: a light-source unit configured to emit a light flux, and including a plurality of light-emitting elements aligned in a main-scanning direction, wherein a direction of the length is the main-scanning direction and a direction of the width is a sub-scanning direction; and a convergent lengthy lens disposed between the illuminated area and the light-source unit, and having a light-incident plane and a light-output plane of the light flux, wherein a longitudinal direction of the convergent lengthy lens corresponds to the main-scanning direction, wherein the light flux emitted from the light-source unit is irradiated onto the illuminated area through the lengthy lens, and wherein at least one of the light-incident plane and the light-output plane of the lengthy lens has a shape, within a cross-section in the sub-scanning-direction of the lengthy lens as a specific light-flux-passing-surface shape, which varies in accordance with positions of the shape of the specific light-flux-passing surface in the main-scanning direction, and wherein the specific light-flux-passing-surface shape cyclically varies in accordance with the positions of the specific light-flux-passing-surface shape in the main-scanning direction.