  Valleytronics, which makes use of the two valleys in graphenes, attracts
considerable attention and a valley filter is expected to be the central
component in valleytronics. We propose the application of the graphene valley
filter using blister defects to the investigation of the valley-dependent
transport properties of the Stone--Wales and blister defects of graphenes by
density functional theory calculations. It is found that the intervalley
transition from the $\mathbf{K}$ valley to the $\mathbf{K}^\prime$ valleys is
completely suppressed in some defects. Using a large bipartite honeycomb cell
including several carbon atoms in a cell and replacing atomic orbitals with
molecular orbitals in the tight-binding model, we demonstrate analytically and
numerically that the symmetry between the A and B sites of the bipartite
honeycomb cell contributes to the suppression of the intervalley transition. In
addition, the universal rule for the atomic structures of the blisters
suppressing the intervalley transition is derived. Furthermore, by introducing
additional carbon atoms to graphenes to form blister defects, we can split the
energies of the states at which resonant scattering occurs on the $\mathrm{K}$
and $\mathrm{K}^\prime$ channel electrons. Because of this split, the fully
valley-polarized current will be achieved by the local application of a gate
voltage.
