Lighting unit and image scanner using same

摘要

A lighting unit is provided with: LED arrays in which light-emitting elements are positioned in an array in a main scanning direction; cylindrical parabolic mirrors that project light emitted from the LED arrays on an illumination region of an illuminated item; and a housing that houses or holds the LED arrays and the cylindrical parabolic mirrors. Each cylindrical parabolic mirror forms a shape in which a cylindrical paraboloid having curvature with respect to a sub-scanning direction has been clipped by an axial plane that is perpendicular to the vertex of the cylindrical paraboloid in the main scanning direction. The LED arrays are positioned so as to include the focal position of the cylindrical paraboloid in the light-emitting region, the central axis in the light-emitting direction being perpendicular to the axial plane.

主权项

1. A lighting unit, comprising:
a light source in which light-emitting elements are positioned in an array in a main scanning direction; a parabolic mirror that projects light emitted from the light source on an illumination region of an illuminated item; and a housing that houses or supports the light source and the parabolic mirror; wherein the parabolic mirror forms a shape in which a cylindrical paraboloid having curvature with respect to a sub-scanning direction has been clipped by an axial plane that is perpendicular to a vertex of the cylindrical paraboloid in the main scanning direction; and the light source is positioned such that a center or an edge of the light-emitting elements is caused to match a focal position of the cylindrical paraboloid, a central axis in the light-emitting direction of the light-emitting elements being perpendicular to the axial plane.