LD(Laser Diode) as a light source generates laser beam with a specific angle and wavelength.
Transmitted laser beam through a lens is collimated and elliptical dot beam.
An user can adjust the beam size by movement of lens group.
The lens called a collimator can’t make an ideal collimated beam.
The collimated beam always have very low divergence angle.
Because LD emits a beam of different divergence angles of vertical and horizontal direction,
the shape of dot has an elliptical beam shape.