ROD LENS ARRAY AND IMAGE SENSOR HEAD THAT USES SAME

摘要

The purpose of the present invention is to provide a rod lens array, which has a deep depth of focus and a small depth of focus spot. The present invention provides a rod lens array that is equipped with at least one line of rod lenses between two substrates, said line of rod lenses having a plurality of columnar rod lenses wherein the refractive index decreases toward the outer periphery from the center, said rod lenses being arranged in such a manner that the center axes of the rod lenses are substantially parallel to each other. The rod lens array is characterized in that the average value (DOFave) of the depth of focus (DOF) is at least 0.9 mm, and the depth of focus spot (DOFcv) in the scanning direction of the line of rod lenses is not more than 12%.