Optical film, including a set of elements disposed adjacent to each other
and an external surface made of optically transparent material, each
element including a lower pyramid being a truncated pyramid, an upper
pyramid being a non-truncated pyramid and a plurality of element planes.
A lower base of the lower pyramid defines the base of the element and an
upper base of the lower pyramid coincides with a lower base of the upper
pyramid. The element bases disposed adjacent to each other form a common
surface of the set of the elements and the lower and upper pyramids
protrude from one side of the common surface. The external surface covers
the plurality of element planes.