Abstract: A light source unit and reader can include a line light source that is attached to a radiator and a rod lens that is attached above the line light source. The radiator with the line light source and the rod lens attached thereto, and a linear strip-shaped reflector arranged in front of the rod lens, are housed in a carriage. The carriage is supported beneath a contact glass and movable in a direction normal to a longitudinal axis of the line light source. The lens has a section in a plane normal to a longitudinal axis of the lens, in which a surface of the lens facing the light source has a curved line that expands or is convexly facing toward the light source. The opposite surface of the lens from the light source has composite curves including a plurality of continuous curves with different radii of curvature. The composite curves are located on both sides of a plane containing the optical axis of the LED and expand or are convex in an opposite direction from the light source.

Abstract: A light source unit and reader can include a line light source that is attached to a radiator and a rod lens that is attached above the line light source. The radiator with the line light source and the rod lens attached thereto, and a linear strip-shaped reflector arranged in front of the rod lens, are housed in a carriage. The carriage is supported beneath contact glass and movable in a direction normal to a longitudinal axis of the line light source. The lens has a section in a plane normal to a longitudinal axis of the lens, in which a surface of the lens facing the light source has a curved line that expands or is convexly facing toward the light source. The opposite surface of the lens from the light source has composite curves including a plurality of continuous curves with different radii of curvature. The composite curves are located on both sides of a plane containing the optical axis of the LED and expand or are convex in an opposite direction from the light source.