A micro prismatic structure is formed inside the light transmission face of a
gradient-index
lens, in which the projections have a height of at least 0.25 and the distance
between the neighboring projections is at most , based on the applied wavelength
. Preferably, the micro prismatic structure has conical projection units
that are aligned in the light transmission face of the lens in a mode of hexagonal,
tetragonal or orthorhombic arrangement. The conical projections may be in any form
of circular cones, polygonal cones, flat-headed circular cones (circular cones
of which the apex has been cut horizontally) or flat-headed polygonal cones .
