  We derive local microscopic optical potentials $U$ systematically for
polarized proton scattering at 65~MeV using the local-potential version of the
Melbourne $g$-matrix folding model. As target nuclei, we take $^{6}$He and
neutron-rich Ne isotopes in addition to stable nuclei of mass number
$A=4$--$208$ in order to clarify mass-number and isotope dependence of $U$. The
local potentials reproduce the experimental data systematically and have
geometries similar to the phenomenological optical potentials for stable
targets. The target density is broadened by the weak-binding nature and/or
deformation of unstable nuclei. For the real spin-orbit part of $U$ the density
broadening weakens the strength and enlarges the radius, whereas for the
central part it enlarges both of the strength and the radius. The
density-broadening effect is conspicuous for halo nuclei such as $^{6}$He and
$^{31}$Ne. Similar discussions are made briefly for proton scattering at
200~MeV. We briefly investigate how the isovector and the non spherical
components of $U$ affect proton scattering.
