  Optical vortex beam of fractional order is generated by the diffraction of a
Gaussian beam using computer generated hologram embedded with mixed screw-edge
dislocation. Unfolding of the generated fractional vortex beam into
eigen-polarization components inside a birefringent crystal results in the
conversion of scalar phase singularity to vector polarization singularities in
the beam cross-section. The evolution of the singularities of the ellipse field
namely C-points (points of undefined major axis) and L-lines (lines of
undefined handedness) across the beam quantifies the transformation. The effect
of the phase morphology dictated by the fractional order of the dislocation,
transverse spatial separation and longitudinal relative phase of the two
eigen-polarization components on determining the complex transverse
polarization structure is investigated. The nature of the generated Poincar\'e
beam is also indicated by projecting the states of polarization on to the
Poincar\'e sphere. With increasing order of dislocation from 0.0 to 1.0 in
fractional steps and increasing relative phase, the partial Poincar\'e beam is
transformed to a full Poincar\'e beam. The transformation of the local
structure around the C-points is measured through the geometric phase due to
the Poincar\'e sphere contour around the C-points for different dynamic phase
difference of the unfolded FOV beams. This study can be useful for different
geometric phase based application of optical vortex beams.
