A laser beam incident on a rod lens has a greater cross-sectional diameter
than that of a rod lens main body, and mirrors are provided near the rod
lens main body to reflect incident light toward the same. Since light of a
strong beam intensity reflected onto the rod lens main body by the mirrors
produces a greater angle than light of weak beam intensity, this
configuration has an effect of increasing the light intensity on the ends
of a resulting line beam and, thus, expands the spreading angle of visible
light in the line beam.
